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Sample records for aerobic soil conditions

  1. Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

    PubMed

    Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

    2014-10-01

    The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities.

  2. Nutrient Transformations in Soils Under Aerobic and Anaerobic Conditions

    NASA Astrophysics Data System (ADS)

    Owens, P.; Lee, L.

    2003-12-01

    Poultry litter is most commonly land applied as a fertilizer for pastures. Soils vary according to landscape position and the biogeochemistry changes within the soils depending on the landscape position. This research focuses on nutrient speciation in aerobic and anaerobic environments. A 3.4 kg Ha-1 chicken litter application rate was used to determine the speciation of nutrients in these two environments. A 50 g sample of Ruston soil was placed in 250 mL centrifuge tubes and continuously stirred in anaerobic and aerobic environments. The Eh and pH were measured daily and a sample was collected at 0, 3, 7, 14 and 21 days. The Eh decreased from around 600 mV at day 0 to near 100 at day 2; whereas the aerobic sample had a decrease to around 450 mV. The pH increased from 6.5 to 7.0 in the anaerobic soil and from 6.5 to around 8.0 in the aerobic soil. The anaerobic soils had a rapid decrease in NO3- and a sharp increase in NH4+ to around 100 mg NH4+ kg-1 soil at day 7. The aerobic soil had an increase in NH4+ to 70 mg Nh4+ kg-1 soil at day 7 then decrease in NH4+ with a corresponding increase in NO3-. Both the anaerobic and aerobic soil had a rapid decrease in PO42- concentrations and remained low for 21 d.

  3. Microbial bioavailability of pyrene in three laboratory-contaminated soils under aerobic and anaerobic conditions.

    PubMed

    Pravecek, Tasha L; Christman, Russell F; Pfaender, Frederic K

    2006-06-30

    Changes in bioavailability of pyrene in three uncontaminated soils were examined under aerobic and anaerobic conditions. Three soils were aerobically aged with pyrene and [(14)C]pyrene for 63 days, then incubated with water, nitrate, or sulfate under aerobic or anaerobic conditions for one year. Under aerobic conditions, microorganisms in two soils mineralized 58-82% of the added [(14)C]pyrene. The two soils amended with nitrate were seen to have enhanced aerobic mineralization rates. In one of these soils, non-extractable pyrene was seen to decrease over the course of the study due to desorption and mineralization, nitrate amendment enhanced this effect. Under anaerobic conditions, generated with a N(2):CO(2)(g) headspace, two soils with nitrate or sulfate amendment showed an increase in extractable [(14)C]pyrene at 365 days relative to inhibited controls, presumably due to microbially mediated oxidation-reduction potential and pH alteration of the soil environment. These observations in different soils incubated under aerobic and anaerobic conditions have important implications relative to the impact of microbial electron acceptors on bioavailability and transport of non-polar organic compounds in the environment suggesting that, given enough time, under the appropriate environmental conditions, non-extractable material becomes bioavailable. This information should be considered when assessing site specific exposure risks at PAH contaminated locations. PMID:16574273

  4. Soil metabolism of [14C]methiozolin under aerobic and anaerobic flooded conditions.

    PubMed

    Hwang, Ki-Hwan; Lim, Jong-Soo; Kim, Sung-Hun; Chang, Hee-Ra; Kim, Kyun; Koo, Suk-Jin; Kim, Jeong-Han

    2013-07-17

    Methiozolin is a new turf herbicide controlling annual bluegrass in various cool- and warm-season turfgrasses. This study was conducted to investigate the fate of methiozolin in soil under aerobic and anaerobic flooded conditions using two radiolabeled tracers, [benzyl-(14)C]- and [isoxazole-(14)C]methiozolin. The mass balance of applied radioactivity ranged from 91.7 to 104.5% in both soil conditions. In the soil under the aerobic condition, [(14)C]methiozolin degraded with time to remain by 17.9 and 15.9% of the applied in soil at 120 days after treatment (DAT). [(14)C]Carbon dioxide and the nonextractable radioactivity increased as the soil aged to reach up to 41.5 and 35.7% for [benzyl-(14)C]methiozolin at 120 DAT, respectively, but 36.1 and 39.8% for [isoxazole-(14)C]methiozolin, respectively, during the same period. The nonextractable residue was associated more with humin and fulvic acid fractions under the aerobic condition. No significant volatile products or metabolites were detected during this study. The half-life of [(14)C]methiozolin was approximately 49 days in the soil under the aerobic condition; however, it could not be estimated in the soil under the anaerobic flooded condition because [(14)C]methiozolin degradation was limited. On the basis of these results, methiozolin is considered to undergo fast degradation by aerobic microbes, but not by anaerobic microbes in soil. PMID:23772889

  5. Soil metabolism of [14C]methiozolin under aerobic and anaerobic flooded conditions.

    PubMed

    Hwang, Ki-Hwan; Lim, Jong-Soo; Kim, Sung-Hun; Chang, Hee-Ra; Kim, Kyun; Koo, Suk-Jin; Kim, Jeong-Han

    2013-07-17

    Methiozolin is a new turf herbicide controlling annual bluegrass in various cool- and warm-season turfgrasses. This study was conducted to investigate the fate of methiozolin in soil under aerobic and anaerobic flooded conditions using two radiolabeled tracers, [benzyl-(14)C]- and [isoxazole-(14)C]methiozolin. The mass balance of applied radioactivity ranged from 91.7 to 104.5% in both soil conditions. In the soil under the aerobic condition, [(14)C]methiozolin degraded with time to remain by 17.9 and 15.9% of the applied in soil at 120 days after treatment (DAT). [(14)C]Carbon dioxide and the nonextractable radioactivity increased as the soil aged to reach up to 41.5 and 35.7% for [benzyl-(14)C]methiozolin at 120 DAT, respectively, but 36.1 and 39.8% for [isoxazole-(14)C]methiozolin, respectively, during the same period. The nonextractable residue was associated more with humin and fulvic acid fractions under the aerobic condition. No significant volatile products or metabolites were detected during this study. The half-life of [(14)C]methiozolin was approximately 49 days in the soil under the aerobic condition; however, it could not be estimated in the soil under the anaerobic flooded condition because [(14)C]methiozolin degradation was limited. On the basis of these results, methiozolin is considered to undergo fast degradation by aerobic microbes, but not by anaerobic microbes in soil.

  6. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  7. Diversity of methanotrophs in Zoige wetland soils under both anaerobic and aerobic conditions.

    PubMed

    Yun, Juanli; Ma, Anzhou; Li, Yaoming; Zhuang, Guoqiang; Wang, Yanfen; Zhang, Hongxun

    2010-01-01

    Zoige wetland is one of the most important methane emission centers in China. The oxidation of methane in the wetland affects global warming, soil ecology and atmospheric chemistry. Despite their global significance, microorganisms that consume methane in Zoige wetland remain poorly characterized. In this study, we investigated methanotrophs diversity in soil samples from both anaerobic site and aerobic site in Zoige wetland using pmoA gene as a molecular marker. The cloning library was constructed according to the pmoA sequences detected. Four clusters of methanotrophs were detected. The phylogenetic tree showed that all four clusters detected were affiliated to type I methanotrophs. Two novel clusters (cluster 1, cluster 2) were found to relate to none of the recognized genera of methanotrophs. These clusters have no cultured representatives and reveal an ecological adaptation of particular uncultured methanotrophs in Zoige wetland. Two clusters were belonging to Methylobacter and Methylococcus separately. Denaturing gradient gel electrophoresis gel bands pattern retrieved from these two samples revealed that the community compositions of anaerobic soil and aerobic soil were different from each other while anaerobic soil showed a higher metanotrophs diversity. Real-time PCR assays of the two samples demonstrated that aerobic soil sample in Zoige wetland was 1.5 times as much copy numbers as anaerobic soil. These data illustrated that methanotrophs are a group of microorganisms influence the methane consumption in Zoige wetland.

  8. Using a tank flow model with PEARL to measure the variation in pesticide persistence between anaerobic and aerobic soil conditions

    NASA Astrophysics Data System (ADS)

    Real, Joaquin; Seiterle-Winn, Natalie; Frances, Felix

    2013-04-01

    Pesticide leaching is very sensitive to the transformation rate (Boesten and Linden, 1991). The values of the transformation rates of the pesticides differ between aerobic and anaerobic soil conditions. The main objective is to determine if there is a significant variation in pesticide persistence between aerobic and anaerobic soil conditions. An auxiliary hydrological model is used with the PEARL model (Leistra et al, 2001). The auxiliary model determines the degree of saturation of the soil at each time step. The value of the degradation rate for a given pesticide in the PEARL model varies depending on the time periods with saturated or unsaturated soil conditions. The proposed auxiliary model has been conceptualized as a static tank flow model based on the actual evapotranspiration of the crop plants. It is based on the RIBAV model (Garcia-Arias et al. 2012) used for the modeling of riparian vegetation zonation. The tank represents a soil column which also includes the superficial root layer. The lower capacity limit of this tank is the permanent wilting moisture of the soil. The upper capacity limit represents the saturated condition of the soil. The tanks input flows are precipitation and irrigation. In contrast, output flows are the actual evapotranspiration and the discharge of the tank. The most relevant model parameters are the soil retention curves, the crop parameters (specially related to root depths and crop coefficients) and the daily meteorological data (such as precipitation and potential evapotranspiration). The main output of the auxiliary model is the relative soil moisture, which determines if the PEARL model should use the transformation rate value for aerobic or for anaerobic conditions. In order to prove the applicability of the model, it was tested with various pesticides, which cover a wide range of transformation rates. The results show that the auxiliary tank model is able to determine the partition of the pesticides degrading in both

  9. Nitrite-Driven Nitrous Oxide Production Under Aerobic Soil Conditions: Kinetics and Biochemical Controls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrite (NO2-) can accumulate during nitrification in soil following fertilizer application. While the role of NO2- as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a functi...

  10. [Population development characteristics of rice crop cultivated on aerobic soil with mulching].

    PubMed

    Sheng, Haijun; Shen, Qirong; Feng, Ke

    2004-01-01

    Field experiments were carried out to study the population development characteristics of rice crop cultivated both on aerobic and waterlogged soil conditions. The results showed that the whole growth duration of rice growing on aerobic soil was one week longer than that on waterlogged soil. Shorter and narrower leaves and smaller LAI of rice population were found on aerobic soil than on waterlogged soil, which resulted in a decreased photosynthesis, smaller amount and lighter weight of rice grains on aerobic soil, compared with those on waterlogged soil. Among the aerobic treatments, more tillers, lower percentage of filled grains and shorter duration of grain forming were found on soils covered with plastic film than on soils covered with semi-decomposed straw or without mulching. The rice grain yield was decreased in the order of waterlogged soil > aerobic soil covered with plastic film > aerobic soil covered with semi-decomposed straw > aerobic soil without mulching.

  11. Degradation of polycyclic aromatic hydrocarbons at low temperature under aerobic and nitrate-reducing conditions in enrichment cultures from northern soils.

    PubMed

    Eriksson, Mikael; Sodersten, Erik; Yu, Zhongtang; Dalhammar, Gunnel; Mohn, William W

    2003-01-01

    The potential for biodegradation of polycyclic aromatic hydrocarbons (PAHs)at low temperature and under anaerobic conditions is not well understood, but such biodegradation would be very useful for remediation of polluted sites. Biodegradation of a mixture of 11 different PAHs with two to five aromatic rings, each at a concentration of 10 micro g/ml, was studied in enrichment cultures inoculated with samples of four northern soils. Under aerobic conditions, low temperature severely limited PAH biodegradation. After 90 days, aerobic cultures at 20 degrees C removed 52 to 88% of the PAHs. The most extensive PAH degradation under aerobic conditions at 7 degrees C,53% removal, occurred in a culture from creosote-contaminated soil. Low temperature did not substantially limit PAH biodegradation under nitrate-reducing conditions. Under nitrate-reducing conditions,naphthalene, 2-methylnaphthalene, fluorene, and phenanthrene were degraded. The most extensive PAH degradation under nitrate-reducing conditions at 7 degrees C, 39% removal, occurred in a culture from fuel-contaminated Arctic soil. In separate transfer cultures from the above Arctic soil, incubated anaerobically at 7 degrees C, removal of 2-methylnaphthalene and fluorene was stoichiometrically coupled to nitrate removal. Ribosomal intergenic spacer analysis suggested that enrichment resulted in a few predominant bacterial populations,including members of the genera Acidovorax,Bordetella, Pseudomonas, Sphingomonas, and Variovorax. Predominant populations from different soils often included phylotypes with nearly identical partial 16S rRNA gene sequences (i.e., same genus) but never included phylotypes with identical ribosomal intergenic spacers (i.e., different species or subspecies). The composition of the enriched communities appeared to be more affected by presence of oxygen, than by temperature or source of the inoculum. PMID:12514005

  12. Degradation of Polycyclic Aromatic Hydrocarbons at Low Temperature under Aerobic and Nitrate-Reducing Conditions in Enrichment Cultures from Northern Soils

    PubMed Central

    Eriksson, Mikael; Sodersten, Erik; Yu, Zhongtang; Dalhammar, Gunnel; Mohn, William W.

    2003-01-01

    The potential for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at low temperature and under anaerobic conditions is not well understood, but such biodegradation would be very useful for remediation of polluted sites. Biodegradation of a mixture of 11 different PAHs with two to five aromatic rings, each at a concentration of 10 μg/ml, was studied in enrichment cultures inoculated with samples of four northern soils. Under aerobic conditions, low temperature severely limited PAH biodegradation. After 90 days, aerobic cultures at 20°C removed 52 to 88% of the PAHs. The most extensive PAH degradation under aerobic conditions at 7°C, 53% removal, occurred in a culture from creosote-contaminated soil. Low temperature did not substantially limit PAH biodegradation under nitrate-reducing conditions. Under nitrate-reducing conditions, naphthalene, 2-methylnaphthalene, fluorene, and phenanthrene were degraded. The most extensive PAH degradation under nitrate-reducing conditions at 7°C, 39% removal, occurred in a culture from fuel-contaminated Arctic soil. In separate transfer cultures from the above Arctic soil, incubated anaerobically at 7°C, removal of 2-methylnaphthalene and fluorene was stoichiometrically coupled to nitrate removal. Ribosomal intergenic spacer analysis suggested that enrichment resulted in a few predominant bacterial populations, including members of the genera Acidovorax, Bordetella, Pseudomonas, Sphingomonas, and Variovorax. Predominant populations from different soils often included phylotypes with nearly identical partial 16S rRNA gene sequences (i.e., same genus) but never included phylotypes with identical ribosomal intergenic spacers (i.e., different species or subspecies). The composition of the enriched communities appeared to be more affected by presence of oxygen, than by temperature or source of the inoculum. PMID:12514005

  13. The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Gorbacheva, M.

    2012-04-01

    M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for

  14. Quantitative assessment of the toxic effects of heavy metals on 1,2-dichloroethane biodegradation in co-contaminated soil under aerobic condition.

    PubMed

    Olaniran, Ademola Olufolahan; Balgobind, Adhika; Pillay, Balakrishna

    2011-10-01

    1,2-Dichloroethane (1,2-DCA) is one of the most hazardous pollutant of soil and groundwater, and is produced in excess of 5.44×10⁹ kg annually. Owing to their toxicity, persistence and potential for bioaccumulation, there is a growing interest in technologies for their removal. Heavy metals are known to be toxic to soil microorganisms at high concentrations and can hinder the biodegradation of organic contaminants. In this study, the inhibitory effect of heavy metals, namely; arsenic, cadmium, mercury and lead, on the aerobic biodegradation of 1,2-DCA by autochthonous microorganisms was evaluated in soil microcosm setting. The presence of heavy metals was observed to have a negative impact on the biodegradation of 1,2-DCA in both soil samples tested, with the toxic effect being more pronounced in loam soil, than in clay soil. Generally, 75 ppm As³⁺, 840 ppm Hg²⁺, and 420 ppm Pb²⁺ resulted in 34.24%, 40.64%, and 45.94% increase in the half live (t½) of 1,2-DCA, respectively, in loam soil, while concentrations above 127.5 ppm Cd²⁺, 840 ppm Hg²⁺ and 420 ppm of Pb²⁺ and less than 75 ppm As³⁺ was required to cause a >10% increase in the t½ of 1,2-DCA in clay soil. A dose-dependent relationship between degradation rate constant (k₁) of 1,2-DCA and metal ion concentrations was observed for all the heavy metals tested, except for Hg²⁺. This study demonstrated that different heavy metals have different impacts on the degree of 1,2-DCA degradation. Results also suggest that the degree of inhibition is metal specific and is also dependent on several factors including; soil type, pH, moisture content and available nutrients.

  15. Aerobic biodegradation of 4-methylquinoline by a soil bacterium.

    PubMed Central

    Sutton, S D; Pfaller, S L; Shann, J R; Warshawsky, D; Kinkle, B K; Vestal, J R

    1996-01-01

    Methylquinolines and related N-heterocyclic aromatic compounds are common contaminants associated with the use of hydrocarbons in both coal gasification and wood treatment processes. These compounds have been found in groundwater, and many are known mutagens. A stable, five-member bacterial consortium able to degrade 4-methylquinoline was established by selective enrichment using soil collected from an abandoned coal gasification site. The consortium was maintained for 5 years by serial transfer in a medium containing 4-methylquinoline. A gram-negative soil bacterium, strain Lep1, was isolated from the consortium and shown to utilize 4-methylquinoline as a source of carbon and energy during growth in liquid medium. A time course experiment demonstrated that both the isolate Lep1 and the consortium containing Lep1 were able to degrade 4-methylquinoline under aerobic conditions. Complete degradation of 4-methylquinoline by either strain Lep1 alone or the consortium was characterized by the production and eventual disappearance of 2-hydroxy-4-methylquinoline, followed by the appearance and persistence of a second metabolite tentatively identified as a hydroxy-4-methylcoumarin. Currently, there is no indication that 4-methylquinoline degradation proceeds differently in the consortium culture compared with Lep1 alone. This is the first report of 4-methylquinoline biodegradation under aerobic conditions. PMID:8702284

  16. Conditioning and Aerobics for Older Americans.

    ERIC Educational Resources Information Center

    Hansen, Joyce

    1980-01-01

    A class designed for the maintenance and gradual improvement of senior citizens' physical fitness includes relaxation training, flexibility and stretching exercises, interval training activities (designed as a link between less strenuous exercise and more strenuous activities), and aerobic exercises. (CJ)

  17. Degradation of 1,3-dichloropropene in aerobic soils

    SciTech Connect

    Batzer, F.; Balcer, J.L.; Wolt, J.D.

    1995-12-31

    The degradation of the soil fumigant, 1,3-dichloropropene (1,3-D), was investigated to determine its rate of degradation and the identify of metabolites in aerobic soils. Studies were conducted in the dark at 25{degrees}C with uniformly {sup 14}C-labeled 1,3-D at a concentration of approximately 100 ug/g on three soils: Wahiawa silty clay, Catlin silt loam and Fuquay loamy sand. Aerobic soil half-lives for 1,3-D were 1.8, 11.5 and 52.5 days on the Wahiawa silty clay, Catlin silt loam, and Fuquay loamy sand, respectively. Degradation of 1,3-D resulted in the formation of cis- and trans-3-chloroallyl alcohol, cis- and trans-3-chloroacrylic acid, numerous minor carboxylic acid metabolites, and carbon dioxide. In addition, there was also extensive incorporation of {sup 14}C labeled material into the soil organic matter of both soils.

  18. Spectroscopic characterization of organic matter of a soil and vinasse mixture during aerobic or anaerobic incubation

    SciTech Connect

    Doelsch, Emmanuel Masion, Armand; Cazevieille, Patrick

    2009-06-15

    Mineralization potentials are often used to classify organic wastes. These methods involve measuring CO{sub 2} production during batch experiments, so variations in chemical compounds are not addressed. Moreover, the physicochemical conditions are not monitored during the reactions. The present study was designed to address these deficiencies. Incubations of a mixture of soil and waste (vinasse at 20% dry matter from a fermentation industry) were conducted in aerobic and anaerobic conditions, and liquid samples obtained by centrifugation were collected at 2 h, 1 d and 28 d. Dissolved organic carbon (DOC) patterns highlighted that: there was a 'soil effect' which increased organic matter (OM) degradation in all conditions compared to vinasse incubated alone; and OM degradation was faster under aerobic conditions since 500 mg kg{sup -1} of C remained after aerobic incubation, as compared to 4000 mg kg{sup -1} at the end of the anaerobic incubation period. No changes were detected by Fourier transform infrared spectroscopy (FTIR) between 2 h and 1 d incubation. At 28 days incubation, the FTIR signal of the aerobic samples was deeply modified, thus confirming the high OM degradation. Under anaerobic conditions, the main polysaccharide contributions ({nu}(C-O)) disappeared at 1000 and 1200 cm{sup -1}, as also confirmed by the {sup 13}C NMR findings. Under aerobic incubation, a 50% decrease in the polysaccharide proportion was observed. Under anaerobic conditions, significant chemical modifications of the organic fraction were detected, namely formation of low molecular weight organic acids.

  19. Decomposition Dynamics and Changes in Chemical Composition of Wheat Straw Residue under Anaerobic and Aerobic Conditions

    PubMed Central

    Gao, Hongjian; Chen, Xi; Wei, Junling; Zhang, Yajie; Zhang, Ligan; Chang, Jiang; Thompson, Michael L.

    2016-01-01

    Soil aeration is a crucial factor that regulates crop residue decomposition, and the chemical composition of decomposing crop residues may change the forms and availability of soil nutrients, such as N and P. However, to date, differences in the chemical composition of crop straw residues after incorporation into soil and during its decomposition under anaerobic vs. aerobic conditions have not been well documented. The objective of the present study was to assess changes in the C-containing functional groups of wheat straw residue during its decomposition in anaerobic and aerobic environments. A 12-month incubation experiment was carried out to investigate the temporal variations of mass, carbon, and nitrogen loss, as well as changes in the chemical composition of wheat (Triticum aestivum L) straw residues under anaerobic and aerobic conditions by measuring C-containing functional groups using solid state nuclear magnetic resonance (NMR) spectroscopy. The residual mass, carbon content, and nitrogen content of the straw residue sharply declined during the initial 3 months, and then slowly decreased during the last incubation period from 3 to 12 months. The decomposition rate constant (k) for mass loss under aerobic conditions (0.022 d-1) was higher than that under anaerobic conditions (0.014 d-1). The residual mass percentage of cellulose and hemicellulose in the wheat straw gradually declined, whereas that of lignin gradually increased during the entire 12-month incubation period. The NMR spectra of C-containing functional groups in the decomposing straw under both aerobic and anaerobic conditions were similar at the beginning of the incubation as well as at 1 month, 6 months, and 12 months. The main alterations in C-containing functional groups during the decomposition of wheat straw were a decrease in the relative abundances of O-alkyl C and an increase in the relative abundances of alkyl C, aromatic C and COO/N-C = O functional groups. The NMR signals of alkyl C

  20. Decomposition Dynamics and Changes in Chemical Composition of Wheat Straw Residue under Anaerobic and Aerobic Conditions.

    PubMed

    Gao, Hongjian; Chen, Xi; Wei, Junling; Zhang, Yajie; Zhang, Ligan; Chang, Jiang; Thompson, Michael L

    2016-01-01

    Soil aeration is a crucial factor that regulates crop residue decomposition, and the chemical composition of decomposing crop residues may change the forms and availability of soil nutrients, such as N and P. However, to date, differences in the chemical composition of crop straw residues after incorporation into soil and during its decomposition under anaerobic vs. aerobic conditions have not been well documented. The objective of the present study was to assess changes in the C-containing functional groups of wheat straw residue during its decomposition in anaerobic and aerobic environments. A 12-month incubation experiment was carried out to investigate the temporal variations of mass, carbon, and nitrogen loss, as well as changes in the chemical composition of wheat (Triticum aestivum L) straw residues under anaerobic and aerobic conditions by measuring C-containing functional groups using solid state nuclear magnetic resonance (NMR) spectroscopy. The residual mass, carbon content, and nitrogen content of the straw residue sharply declined during the initial 3 months, and then slowly decreased during the last incubation period from 3 to 12 months. The decomposition rate constant (k) for mass loss under aerobic conditions (0.022 d-1) was higher than that under anaerobic conditions (0.014 d-1). The residual mass percentage of cellulose and hemicellulose in the wheat straw gradually declined, whereas that of lignin gradually increased during the entire 12-month incubation period. The NMR spectra of C-containing functional groups in the decomposing straw under both aerobic and anaerobic conditions were similar at the beginning of the incubation as well as at 1 month, 6 months, and 12 months. The main alterations in C-containing functional groups during the decomposition of wheat straw were a decrease in the relative abundances of O-alkyl C and an increase in the relative abundances of alkyl C, aromatic C and COO/N-C = O functional groups. The NMR signals of alkyl C

  1. Decomposition Dynamics and Changes in Chemical Composition of Wheat Straw Residue under Anaerobic and Aerobic Conditions.

    PubMed

    Gao, Hongjian; Chen, Xi; Wei, Junling; Zhang, Yajie; Zhang, Ligan; Chang, Jiang; Thompson, Michael L

    2016-01-01

    Soil aeration is a crucial factor that regulates crop residue decomposition, and the chemical composition of decomposing crop residues may change the forms and availability of soil nutrients, such as N and P. However, to date, differences in the chemical composition of crop straw residues after incorporation into soil and during its decomposition under anaerobic vs. aerobic conditions have not been well documented. The objective of the present study was to assess changes in the C-containing functional groups of wheat straw residue during its decomposition in anaerobic and aerobic environments. A 12-month incubation experiment was carried out to investigate the temporal variations of mass, carbon, and nitrogen loss, as well as changes in the chemical composition of wheat (Triticum aestivum L) straw residues under anaerobic and aerobic conditions by measuring C-containing functional groups using solid state nuclear magnetic resonance (NMR) spectroscopy. The residual mass, carbon content, and nitrogen content of the straw residue sharply declined during the initial 3 months, and then slowly decreased during the last incubation period from 3 to 12 months. The decomposition rate constant (k) for mass loss under aerobic conditions (0.022 d-1) was higher than that under anaerobic conditions (0.014 d-1). The residual mass percentage of cellulose and hemicellulose in the wheat straw gradually declined, whereas that of lignin gradually increased during the entire 12-month incubation period. The NMR spectra of C-containing functional groups in the decomposing straw under both aerobic and anaerobic conditions were similar at the beginning of the incubation as well as at 1 month, 6 months, and 12 months. The main alterations in C-containing functional groups during the decomposition of wheat straw were a decrease in the relative abundances of O-alkyl C and an increase in the relative abundances of alkyl C, aromatic C and COO/N-C = O functional groups. The NMR signals of alkyl C

  2. Photoautotrophic hydrogen production by eukaryotic microalgae under aerobic conditions.

    PubMed

    Hwang, Jae-Hoon; Kim, Hyun-Chul; Choi, Jeong-A; Abou-Shanab, R A I; Dempsey, Brian A; Regan, John M; Kim, Jung Rae; Song, Hocheol; Nam, In-Hyun; Kim, Su-Nam; Lee, Woojung; Park, Donghee; Kim, Yongje; Choi, Jaeyoung; Ji, Min-Kyu; Jung, Woosik; Jeon, Byong-Hun

    2014-01-01

    Eukaryotic algae and cyanobacteria produce hydrogen under anaerobic and limited aerobic conditions. Here we show that novel microalgal strains (Chlorella vulgaris YSL01 and YSL16) upregulate the expression of the hydrogenase gene (HYDA) and simultaneously produce hydrogen through photosynthesis, using CO2 as the sole source of carbon under aerobic conditions with continuous illumination. We employ dissolved oxygen regimes that represent natural aquatic conditions for microalgae. The experimental expression of HYDA and the specific activity of hydrogenase demonstrate that C. vulgaris YSL01 and YSL16 enzymatically produce hydrogen, even under atmospheric conditions, which was previously considered infeasible. Photoautotrophic H2 production has important implications for assessing ecological and algae-based photolysis.

  3. Degradation of triclosan under aerobic, anoxic, and anaerobic conditions.

    PubMed

    Gangadharan Puthiya Veetil, Prajeesh; Vijaya Nadaraja, Anupama; Bhasi, Arya; Khan, Sudheer; Bhaskaran, Krishnakumar

    2012-07-01

    Triclosan (2, 4, 4'-trichloro-2'-hydroxyl diphenyl ether) is a broad-spectrum antimicrobial agent present in a number of house hold consumables. Aerobic and anaerobic enrichment cultures tolerating triclosan were developed and 77 bacterial strains tolerating triclosan at different levels were isolated from different inoculum sources. Biodegradation of triclosan under aerobic, anoxic (denitrifying and sulphate reducing conditions), and anaerobic conditions was studied in batch cultures with isolated pure strains and enrichment consortium developed. Under aerobic conditions, the isolated strains tolerated triclosan up to 1 g/L and degraded the compound in inorganic-mineral-broth and agar media. At 10 mg/L level triclosan, 95 ± 1.2% was degraded in 5 days, producing phenol, catechol and 2, 4-dichlorophenol as the degradation products. The strains were able to metabolize triclosan and its degradation products in the presence of monooxygenase inhibitor 1-pentyne. Under anoxic/anaerobic conditions highest degradation (87%) was observed in methanogenic system with acetate as co-substrate and phenol, catechol, and 2, 4-dichlorophenol were among the products. Three of the isolated strains tolerating 1 g/L triclosan were identified as Pseudomonas sp. (BDC 1, 2, and 3).

  4. Enhanced biodegradation of methoxychlor in soil under sequential environmental conditions.

    PubMed Central

    Fogel, S; Lancione, R L; Sewall, A E

    1982-01-01

    Ring-U-[14C]methoxychlor [1,1-bis(p-methoxyphenyl)-2,2,2-trichloroethane] was incubated in soil under aerobic and anaerobic conditions. Primary degradation of methoxychlor occurred under anaerobic conditions, but not under aerobic conditions, after 3 months of incubation. Analysis of soil extracts, using gas chromatography, demonstrated that only 10% of the compound remained at initial concentrations of 10 and 100 ppm (wt/wt) of methoxychlor. Evidence is presented that a dechlorination reaction was responsible for primary degradation of methoxychlor. Analysis of soils treated with 100 ppm of methoxychlor in the presence of 2% HgCl2 showed that 100% of the compound remained after 3 months, indicating that degradation in the unpoisoned flasks was biologically mediated. Methanogenic organisms, however, are probably not involved, as strong inhibition of methane production was observed in all soils treated with methoxychlor. During the 3-month incubation period, little or no evaluation of 14CO2 or 14CH4 occurred under either aerobic or anaerobic conditions. Cometabolic processes may be responsible for the extensive molecular changes which occurred with methoxychlor because the rate of its disappearance from soil was observed to level off after exhaustion of soil organic matter. After this incubation period, soils previously incubated under anaerobic conditions were converted to aerobic conditions. The rates of 14CO2 evolution from soils exposed to anaerobic and aerobic sequences of environments ranged from 10- to 70-fold greater than that observed for soils exposed solely to an aerobic environment. PMID:7125645

  5. Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

    PubMed

    Tuovinen, Olli H; Deshmukh, Vaidehi; Özkaya, Bestamin; Radosevich, Mark

    2015-01-01

    The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another. PMID:26273756

  6. Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

    PubMed

    Tuovinen, Olli H; Deshmukh, Vaidehi; Özkaya, Bestamin; Radosevich, Mark

    2015-01-01

    The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another.

  7. Aerobic Conditions are Required for Rapid Carbon Losses following Permafrost Thaw

    NASA Astrophysics Data System (ADS)

    Cooper, M. D. A.; Estop-Aragones, C.

    2015-12-01

    Permafrost soils store between 1,330-1,580 billion tonnes of carbon (C), which may start to be released to the atmosphere if warming promotes widespread thaw. Considerable uncertainty remains regarding how rapidly this C may be released and what proportion will be released as the more powerful greenhouse gas, methane (CH4), rather than carbon dioxide (CO2). Central to answering these questions, is quantifying in situ rates of old, previously-frozen C release under aerobic conditions versus anaerobic conditions. To meet this aim, we investigated the amount and form (CH4 versus CO2) of previously-frozen C released in response to 1) forest fire-induced permafrost thaw (aerobic soil conditions) and 2) permafrost plateau collapse in peatlands which results in waterlogging (anaerobic conditions), in the Yukon and Northwest Territories of Canada. We quantified in situ rates of CO2 and CH4 release, using a novel collar design to either include or exclude C released from deep soil layers, and collected samples for 14CO2 and 14CH4 analysis. Our 14CO2 results identified substantial rates of old C release from burnt forests where the organic horizon was thick and deep thaw was observed. In contrast, in the wetlands old C release was barely detectable as CO2 (<1%), and, although high CH4 fluxes were measured, a maximum of 1.5-2g m-2 yr-1 was derived from previously-frozen C. Furthermore, because peat accumulation increased substantially (>4 times), , thaw resulted in net C gain in the wetland. However, the high rate of CH4 release, albeit derived mainly from contemporary sources, means that permafrost plateau collapse can still represent a positive feedback to climate change in terms of global warming potential. Overall, our results indicate a much greater release of permafrost C under aerobic conditions, with little release of previously-frozen C as either CO2 or CH4 under anaerobic conditions.

  8. Stabilisation of microalgae: Iodine mobilisation under aerobic and anaerobic conditions.

    PubMed

    Han, Wei; Clarke, William; Pratt, Steven

    2015-10-01

    Mobilisation of iodine during microalgae stabilisation was investigated, with the view of assessing the potential of stabilised microalgae as an iodine-rich fertiliser. An iodine-rich waste microalgae (0.35 ± 0.05 mg I g(-1) VS(added)) was stabilised under aerobic and anaerobic conditions. Iodine mobilisation was linearly correlated with carbon emission, indicating iodine was in the form of organoiodine. Comparison between iodine and nitrogen mobilisation relative to carbon emission indicated that these elements were, at least in part, housed separately within the cells. After stabilisation, there were 0.22 ± 0.05 and 0.19 ± 0.01 mg g(-1) VS(added) iodine remaining in the solid in the aerobic and anaerobic processed material respectively, meaning 38 ± 5.0% (aerobic) and 50 ± 8.6% (anaerobic) of the iodine were mobilised, and consequently lost from the material. The iodine content of the stabilised material is comparable to the iodine content of some seaweed fertilisers, and potentially satisfies an efficient I-fertilisation dose.

  9. Microbial removal of atmospheric carbon tetrachloride in bulk aerobic soils.

    PubMed

    Mendoza, Y; Goodwin, K D; Happell, J D

    2011-09-01

    Atmospheric concentrations of carbon tetrachloride (CCl(4)) were removed by bulk aerobic soils from tropical, subtropical, and boreal environments. Removal was observed in all tested soil types, indicating that the process was widespread. The flux measured in field chamber experiments was 0.24 ± 0.10 nmol CCl(4) (m(2) day)(-1) (average ± standard deviation [SD]; n = 282). Removal of CCl(4) and removal of methane (CH(4)) were compared to explore whether the two processes were linked. Removal of both gases was halted in laboratory samples that were autoclaved, dry heated, or incubated in the presence of mercuric chloride (HgCl(2)). In marl soils, treatment with antibiotics such as tetracycline and streptomycin caused partial inhibition of CCl(4) (50%) and CH(4) (76%) removal, but removal was not affected in soils treated with nystatin or myxothiazol. These data indicated that bacteria contributed to the soil removal of CCl(4) and that microeukaryotes may not have played a significant role. Amendments of methanol, acetate, and succinate to soil samples enhanced CCl(4) removal by 59%, 293%, and 72%, respectively. Additions of a variety of inhibitors and substrates indicated that nitrification, methanogenesis, or biological reduction of nitrate, nitrous oxide, or sulfate (e.g., occurring in possible anoxic microzones) did not play a significant role in the removal of CCl(4). Methyl fluoride inhibited removal of CH(4) but not CCl(4), indicating that CH(4) and CCl(4) removals were not directly linked. Furthermore, CCl(4) removal was not affected in soils amended with copper sulfate or methane, supporting the results with MeF and suggesting that the observed CCl(4) removal was not significantly mediated by methanotrophs.

  10. Climatic thresholds for pedogenic iron oxides under aerobic conditions: Processes and their significance in paleoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    Long, Xiaoyong; Ji, Junfeng; Barrón, Vidal; Torrent, José

    2016-10-01

    Iron oxides are widely distributed across the surface of the Earth as a result of the aerobic weathering of primary Fe-bearing minerals. Pedogenic iron oxides which consist mainly of hematite (Hm), goethite (Gt), maghemite (Mgh), are often concentrated synchronously in aerobic soils under low to moderate rainfall regimes. Magnetic susceptibility (χ) and redness, which respectively reflect the content of Mgh and Hm in soils, are considered reasonable pedogenic and climatic indicators in soil taxonomy and paleorainfall reconstruction. However, under high rainfall regimes, the grain growth of Mgh and transformation to Hm, combined with the prior formation of Gt under conditions of high relative humidity (RH), can result in magnetic reduction and dramatic yellowing of soils and sediments, which explains the existence of rainfall thresholds for Mgh and Hm at a large scale even before the pedogenic environment turns anaerobic. In order to capture the rainfall thresholds for Mgh and Hm occurring under aerobic conditions, we explored a tropical transect across a granitic region where the soil color turned from red to yellow under a wide rainfall range of 900-2200 mm/yr and a corresponding mean annual RH range of 77%-85%. We observed a lower rainfall threshold of ∼1500 mm/yr and a corresponding RH ∼80% for Mgh and Hm along this transect, as well as a higher rainfall threshold of ∼1700 mm/yr and a corresponding RH of ∼81% for Gt and total pedogenic iron oxides (citrate/bicarbonate/dithionite-extractable Fe, Fed). Cross-referencing with comparable studies in temperate and subtropical regions, we noted that the rainfall or RH thresholds for Fed and Hm or Mgh likewise increase with temperature. Moreover, the different thresholds for total and individual iron oxide phase indicates that a negative correlation between chemical weathering intensity and redness or χ in sediment sequences can occur under the prevalent climate regime just between their thresholds. Finally

  11. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  12. Aerobic biodegradation of propylene glycol by soil bacteria.

    PubMed

    Toscano, Giuseppe; Cavalca, Lucia; Letizia Colarieti, M; Scelza, Rosalia; Scotti, Riccardo; Rao, Maria A; Andreoni, Vincenza; Ciccazzo, Sonia; Greco, Guido

    2013-09-01

    Propylene glycol (PG) is a main component of aircraft deicing fluids and its extensive use in Northern airports is a source of soil and groundwater contamination. Bacterial consortia able to grow on PG as sole carbon and energy source were selected from soil samples taken along the runways of Oslo Airport Gardermoen site (Norway). DGGE analysis of enrichment cultures showed that PG-degrading populations were mainly composed by Pseudomonas species, although Bacteroidetes were found, as well. Nineteen bacterial strains, able to grow on PG as sole carbon and energy source, were isolated and identified as different Pseudomonas species. Maximum specific growth rate of mixed cultures in the absence of nutrient limitation was 0.014 h(-1) at 4 °C. Substrate C:N:P molar ratios calculated on the basis of measured growth yields are in good agreement with the suggested values for biostimulation reported in literature. Therefore, the addition of nutrients is suggested as a suitable technique to sustain PG aerobic degradation at the maximum rate by autochthonous microorganisms of unsaturated soil profile.

  13. Cyanide toxicity in hepatocytes under aerobic and anaerobic conditions.

    PubMed

    Aw, T Y; Jones, D P

    1989-09-01

    The effect of cyanide on cell viability and mitochondrial function was studied in hepatocytes exposed to air or argon. Cells were more susceptible to cyanide toxicity under air than under argon. Analysis of the disposition of cyanide showed that the difference in susceptibility to KCN was not due to O2-dependent differences in cyanide metabolism or elimination. Studies of mitochondrial function revealed that cyanide under aerobic conditions resulted in substantial swelling of the mitochondria, which corresponded to a matrix loading of phosphate. In addition, cyanide caused a loss of the mitochondrial protonmotive force. This was in contrast to the results for cells exposed to 30 min of anoxia alone in which there was no loss of mitochondrial delta pH, no detectable change in mitochondrial volume, and little matrix loading of phosphate. These results show that at least some of the protective mechanisms elicited by anoxia (B. S. Andersson, T. Y. Aw, and D. P. Jones. Am. J. Physiol. 252 (Cell Physiol. 21): C349-C355, 1987) are not elicited by cyanide alone. Thus cyanide under aerobic conditions does not provide a completely valid model for simple anoxia. Moreover, the results suggest that the molecular sensor necessary to signal suppression of metabolic and transport functions during neahypoxia is dependent on O2 and is neither stimulated nor antagonized by KCN. PMID:2782387

  14. Aerobic versus Anaerobic Microbial Degradation of Clothianidin under Simulated California Rice Field Conditions.

    PubMed

    Mulligan, Rebecca A; Tomco, Patrick L; Howard, Megan W; Schempp, Tabitha T; Stewart, Davis J; Stacey, Phillip M; Ball, David B; Tjeerdema, Ronald S

    2016-09-28

    Microbial degradation of clothianidin was characterized under aerobic and anaerobic California rice field conditions. Rate constants (k) and half-lives (DT50) were determined for aerobic and anaerobic microcosms, and an enrichment experiment was performed at various nutrient conditions and pesticide concentrations. Temperature effects on anaerobic degradation rates were determined at 22 ± 2 and 35 ± 2 °C. Microbial growth was assessed in the presence of various pesticide concentrations, and distinct colonies were isolated and identified. Slow aerobic degradation was observed, but anaerobic degradation occurred rapidly at both 25 and 35 °C. Transformation rates and DT50 values in flooded soil at 35 ± 2 °C (k = -7.16 × 10(-2) ± 3.08 × 10(-3) day(-1), DT50 = 9.7 days) were significantly faster than in 25 ± 2 °C microcosms (k= -2.45 × 10(-2) ± 1.59 × 10(-3) day(-1), DT50 = 28.3 days). At the field scale, biodegradation of clothianidin will vary with extent of oxygenation.

  15. Aerobic versus Anaerobic Microbial Degradation of Clothianidin under Simulated California Rice Field Conditions.

    PubMed

    Mulligan, Rebecca A; Tomco, Patrick L; Howard, Megan W; Schempp, Tabitha T; Stewart, Davis J; Stacey, Phillip M; Ball, David B; Tjeerdema, Ronald S

    2016-09-28

    Microbial degradation of clothianidin was characterized under aerobic and anaerobic California rice field conditions. Rate constants (k) and half-lives (DT50) were determined for aerobic and anaerobic microcosms, and an enrichment experiment was performed at various nutrient conditions and pesticide concentrations. Temperature effects on anaerobic degradation rates were determined at 22 ± 2 and 35 ± 2 °C. Microbial growth was assessed in the presence of various pesticide concentrations, and distinct colonies were isolated and identified. Slow aerobic degradation was observed, but anaerobic degradation occurred rapidly at both 25 and 35 °C. Transformation rates and DT50 values in flooded soil at 35 ± 2 °C (k = -7.16 × 10(-2) ± 3.08 × 10(-3) day(-1), DT50 = 9.7 days) were significantly faster than in 25 ± 2 °C microcosms (k= -2.45 × 10(-2) ± 1.59 × 10(-3) day(-1), DT50 = 28.3 days). At the field scale, biodegradation of clothianidin will vary with extent of oxygenation. PMID:27499061

  16. Parallel pathways of ethoxylated alcohol biodegradation under aerobic conditions.

    PubMed

    Zembrzuska, Joanna; Budnik, Irena; Lukaszewski, Zenon

    2016-07-01

    Non-ionic surfactants (NS) are a major component of the surfactant flux discharged into surface water, and alcohol ethoxylates (AE) are the major component of this flux. Therefore, biodegradation pathways of AE deserve more thorough investigation. The aim of this work was to investigate the stages of biodegradation of homogeneous oxyethylated dodecanol C12E9 having 9 oxyethylene subunits, under aerobic conditions. Enterobacter strain Z3 bacteria were chosen as biodegrading organisms under conditions with C12E9 as the sole source of organic carbon. Bacterial consortia of river water were used in a parallel test as an inoculum for comparison. The LC-MS technique was used to identify the products of biodegradation. Liquid-liquid extraction with ethyl acetate was selected for the isolation of C12E9 and metabolites from the biodegradation broth. The LC-MS/MS technique operating in the multiple reaction monitoring (MRM) mode was used for quantitative determination of C12E9, C12E8, C12E7 and C12E6. Apart from the substrate, the homologues C12E8, C12E7 and C12E6, being metabolites of C12E9 biodegradation by shortening of the oxyethylene chain, as well as intermediate metabolites having a carboxyl end group in the oxyethylene chain (C12E8COOH, C12E7COOH, C12E6COOH and C12E5COOH), were identified. Poly(ethylene glycols) (E) having 9, 8 and 7 oxyethylene subunits were also identified, indicating parallel central fission of C12E9 and its metabolites. Similar results were obtained with river water as inoculum. It is concluded that AE, under aerobic conditions, are biodegraded via two parallel pathways: by central fission with the formation of PEG, and by Ω-oxidation of the oxyethylene chain with the formation of carboxylated AE and subsequent shortening of the oxyethylene chain by a single unit. PMID:27037882

  17. Iron plaque formed under aerobic conditions efficiently immobilizes arsenic in Lupinus albus L roots.

    PubMed

    Fresno, Teresa; Peñalosa, Jesús M; Santner, Jakob; Puschenreiter, Markus; Prohaska, Thomas; Moreno-Jiménez, Eduardo

    2016-09-01

    Arsenic is a non-threshold carcinogenic metalloid. Thus, human exposure should be minimised, e.g. by chemically stabilizing As in soil. Since iron is a potential As immobiliser, it was investigated whether root iron plaque, formed under aerobic conditions, affects As uptake, metabolism and distribution in Lupinus albus plants. White lupin plants were cultivated in a continuously aerated hydroponic culture containing Fe/EDDHA or FeSO4 and exposed to arsenate (5 or 20 μM). Only FeSO4 induced surficial iron plaque in roots. LA-ICP-MS analysis accomplished on root sections corroborated the association of As to this surficial Fe. Additionally, As(V) was the predominant species in FeSO4-treated roots, suggesting less efficient As uptake in the presence of iron plaque. Fe/EDDHA-exposed roots neither showed such surficial FeAs co-localisation nor As(V) accumulation; in contrast As(III) was the predominant species in root tissue. Furthermore, FeSO4-treated plants showed reduced shoot-to-root As ratios, which were >10-fold lower compared to Fe/EDDHA treatment. Our results highlight the role of an iron plaque formed in roots of white lupin under aerobic conditions on As immobilisation. These findings, to our knowledge, have not been addressed before for this plant and have potential implications on soil remediation (phytostabilisation) and food security (minimising As in crops). PMID:27263113

  18. Iron plaque formed under aerobic conditions efficiently immobilizes arsenic in Lupinus albus L roots.

    PubMed

    Fresno, Teresa; Peñalosa, Jesús M; Santner, Jakob; Puschenreiter, Markus; Prohaska, Thomas; Moreno-Jiménez, Eduardo

    2016-09-01

    Arsenic is a non-threshold carcinogenic metalloid. Thus, human exposure should be minimised, e.g. by chemically stabilizing As in soil. Since iron is a potential As immobiliser, it was investigated whether root iron plaque, formed under aerobic conditions, affects As uptake, metabolism and distribution in Lupinus albus plants. White lupin plants were cultivated in a continuously aerated hydroponic culture containing Fe/EDDHA or FeSO4 and exposed to arsenate (5 or 20 μM). Only FeSO4 induced surficial iron plaque in roots. LA-ICP-MS analysis accomplished on root sections corroborated the association of As to this surficial Fe. Additionally, As(V) was the predominant species in FeSO4-treated roots, suggesting less efficient As uptake in the presence of iron plaque. Fe/EDDHA-exposed roots neither showed such surficial FeAs co-localisation nor As(V) accumulation; in contrast As(III) was the predominant species in root tissue. Furthermore, FeSO4-treated plants showed reduced shoot-to-root As ratios, which were >10-fold lower compared to Fe/EDDHA treatment. Our results highlight the role of an iron plaque formed in roots of white lupin under aerobic conditions on As immobilisation. These findings, to our knowledge, have not been addressed before for this plant and have potential implications on soil remediation (phytostabilisation) and food security (minimising As in crops).

  19. Aerobic biotransformation of 2,4-dinitroanisole in soil and soil Bacillus sp.

    PubMed

    Perreault, Nancy N; Manno, Dominic; Halasz, Annamaria; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2012-04-01

    2,4-Dinitroanisole (DNAN) is a low sensitive melt-cast chemical being tested by the Military Industry as a replacement for 2,4,6-trinitrotoluene (TNT) in explosive formulations. Little is known about the fate of DNAN and its transformation products in the natural environment. Here we report aerobic biotransformation of DNAN in artificially contaminated soil microcosms. DNAN was completely transformed in 8 days in soil slurries supplemented with carbon and nitrogen sources. DNAN was completely transformed in 34 days in slurries supplemented with carbons alone and persisted in unamended microcosms. A strain of Bacillus (named 13G) that transformed DNAN by co-metabolism was isolated from the soil. HPLC and LC-MS analyses of cell-free and resting cell assays of Bacillus 13G with DNAN showed the formation of 2-amino-4-nitroanisole as the major end-product via the intermediary formation of the arylnitroso (ArNO) and arylhydroxylamino (ArNHOH) derivatives, indicating regioselective reduction of the ortho-nitro group. A series of secondary reactions involving ArNO and ArNHOH gave the corresponding azoxy- and azo-dimers. Acetylated and demethylated products were identified. Overall, this paper provides the evidence of fast DNAN transformation by the indigenous microbial populations of an amended soil with no history of contamination with explosives and a first insight into the aerobic metabolism of DNAN by the soil isolate Bacillus 13G.

  20. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  1. Pyrosequence analysis of bacterial communities in aerobic bioreactors treating polycyclic aromatic hydrocarbon-contaminated soil

    PubMed Central

    Richardson, Stephen D.; Aitken, Michael D.

    2011-01-01

    Two aerobic, lab-scale, slurry-phase bioreactors were used to examine the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and the associated bacterial communities. The two bioreactors were operated under semi-continuous (draw-and-fill) conditions at a residence time of 35 days, but one was fed weekly and the other monthly. Most of the quantified PAHs, including high-molecular-weight compounds, were removed to a greater extent in the weekly-fed bioreactor, which achieved total PAH removal of 76%. Molecular analyses, including pyrosequencing of 16S rRNA genes, revealed significant shifts in the soil bacterial communities after introduction to the bioreactors and differences in the abundance and types of bacteria in each of the bioreactors. The weekly-fed bioreactor displayed a more stable bacterial community with gradual changes over time, whereas the monthly-fed bioreactor community was less consistent and may have been more strongly influenced by the influx of untreated soil during feeding. Phylogenetic groups containing known PAH-degrading bacteria previously identified through stable-isotope probing of the untreated soil were differentially affected by bioreactor conditions. Sequences from members of the Acidovorax and Sphingomonas genera, as well as the uncultivated ‘‘Pyrene Group 2’’ were abundant in the bioreactors. However, the relative abundances of sequences from the Pseudomonas, Sphingobium, and Pseudoxanthomonas genera, as well as from a group of unclassified anthracene degraders, were much lower in the bioreactors compared to the untreated soil. PMID:21369833

  2. Effects of three feedback conditions on aerobic swim speeds

    PubMed Central

    Pérez, Pedro; Llana, Salvador; Brizuela, Gabriel; Encarnación, Alberto

    2009-01-01

    The purpose of this study was twofold: (a) to develop an underwater chronometer capable to provide feedback while the athlete is swimming, as well as being a control tool for the coach, and (b) to analyse its feedback effect on swim pace control compared with feedback provided by the coach and with no feedback, in 25 m and 50 m swimming pools. 30 male swimmers of national level volunteer to participate. Each swimmer swam 3 x 200 m at aerobic speed (AS) and 3 x 200 m just under the anaerobic threshold speed (AnS), each swam repetition with a different feedback condition: chronometer, coach and without feedback. Results (a) validate the chronometer system developed and (b) show that swimmers pace control is affected by the type of feedback provided, the swim speed elected and the size of the swimming pool. Key points Providing concurrent feedback to swimmers improves theis swimming pace control. It is more important to provide feedback to control swim pace when the swimming pool is 50m long. Technological development as this chronometer system, could offload coach work, so coach can focus its time and attention on other performance aspects or other swimmers. Technological developments are more accepted by coaches when they don’t interfere on swimmers execution, that is, whet it is not necessary to implement the swimmer with cables and apparatus. PMID:24150553

  3. Aerobic conditions increase isoprenoid biosynthesis pathway gene expression levels for carotenoid production in Enterococcus gilvus.

    PubMed

    Hagi, Tatsuro; Kobayashi, Miho; Nomura, Masaru

    2015-06-01

    Some lactic acid bacteria that harbour carotenoid biosynthesis genes (crtNM) can produce carotenoids. Although aerobic conditions can increase carotenoid production and crtNM expression levels, their effects on the pathways that synthesize carotenoid precursors such as mevalonate and isoprene are not completely understood. In this study, we investigated whether aerobic conditions affected gene expression levels involved in the isoprenoid biosynthesis pathway that includes the mevalonate and isoprene biosynthesis pathways in Enterococcus gilvus using real-time quantitative reverse transcription PCR. NADH oxidase (nox) and superoxide dismutase (sod) gene expression levels were investigated as controls for aerobic conditions. The expression levels of nox and sod under aerobic conditions were 7.2- and 8.0-fold higher, respectively, than those under anaerobic conditions. Aerobic conditions concomitantly increased the expression levels of crtNM carotenoid biosynthesis genes. HMG-CoA synthase gene expression levels in the mevalonate pathway were only slightly increased under aerobic conditions, whereas the expression levels of HMG-CoA reductase and five other genes in the isoprene biosynthesis pathways were 1.2-2.3-fold higher than those under anaerobic conditions. These results demonstrated that aerobic conditions could increase the expression levels of genes involved in the isoprenoid biosynthesis pathway via mevalonate in E. gilvus.

  4. Remediation of explosive-polluted soil in slurry phase by aerobic biostimulation

    NASA Astrophysics Data System (ADS)

    Xin, Baoping; Shen, Mengyue; Aslam, Hina; Wu, Feng

    2013-06-01

    There is a great volume of polluted soil by 2,4,6-trinitrotoluene (TNT) manufacturing wastewater containing dozen of nitrocompounds in China. In this study, biostimulation was used for remediating the explosive-polluted soil in aerobic bioslurry by monitoring the removal of total organic carbon (TOC). The results showed that the pulp density had almost no effect on TOC removal; whereas the acetone addition evidently improved remediation efficiency of the polluted soil by intrinsic microorganism, and the TOC removal increased from 25% to 38.4% when dose of acetone increased from 0% to 4% (v/v). The maximum TOC removal of 49.1% was achieved through further adjusting pH at 9.0 and temperature at 30 °C. The second order reaction fits well removal dynamics of TOC under the optimum conditions. With the average conditions, liquid phase TOC decreased from 3404 to 3144 mg/L and solid phase TOC dropped from 1022 to 104 mg/L, leading to toxicity decline by 35%; the optimum condition witnessed 48.9% of TOC removal from 4500 to 2300 mg/L in liquid phase, causing toxicity drop by 62%.

  5. Microbial transformation of 2,4,6-trinitrotoluene in aerobic soil columns

    SciTech Connect

    Bruns-Nagel, D.; Breitung, J.; Loew, E. von

    1996-07-01

    The explosive 2,4,6-trinitrotoluene (TNT) is a common contaminant of soil and groundwater at former muntion plants and their dumping sites. TNT is toxic to numerous organisms. This paper reports on an efficient aerobic circulating percolation reactor system for the microbial detoxification of TNT-contaminated soil. 36 refs., 4 figs., 1 tab.

  6. AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

    EPA Science Inventory

    The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

  7. Biodegradation of three selected benzotriazoles in aquifer materials under aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Liu, You-Sheng; Ying, Guang-Guo; Shareef, Ali; Kookana, Rai S.

    2013-08-01

    We investigated the biodegradation of three selected benzotriazoles (BTs), namely benzotriazole (BT), 5-methyl-benzotriazole (5-TTri) and 5-chloro-benzotriazole (CBT), in aquifer materials. Biodegradation experiments were conducted in microcosms with fresh groundwater and aquifer sediment materials under aerobic and anaerobic (nitrate, sulfate, and Fe (III) reducing) conditions. All three BTs were degraded by microorganisms in aquifer materials under aerobic and anaerobic conditions. Under aerobic conditions, BT and 5-TTri were found to be degraded fastest with their half-lives of 43 days and 31 days, respectively, among the redox conditions used. Under anaerobic conditions, CBT was found to be degraded better with its half-life of 21 days under nitrate reducing conditions than under aerobic conditions with its half-life of 47 days. The two BT derivatives 5-TTri and CBT could be biotransformed into BT via demethylation and dechlorination reactions, respectively.

  8. Acetic Acid Increases Stability of Silage under Aerobic Conditions

    PubMed Central

    Danner, H.; Holzer, M.; Mayrhuber, E.; Braun, R.

    2003-01-01

    The effects of various compounds on the aerobic stability of silages were evaluated. It has been observed that inoculation of whole-crop maize with homofermentative lactic acid bacteria leads to silages which have low stability against aerobic deterioration, while inoculation with heterofermentative lactic acid bacteria, such as Lactobacillus brevis or Lactobacillus buchneri, increases stability. Acetic acid has been proven to be the sole substance responsible for the increased aerobic stability, and this acid acts as an inhibitor of spoilage organisms. Therefore, stability increases exponentially with acetic acid concentration. Only butyric acid has a similar effect. Other compounds, like lactic acid, 1,2-propanediol, and 1-propanol, have been shown to have no effect, while fructose and mannitol reduce stability. PMID:12514042

  9. Biochar increases plant available water in a sandy soil under an aerobic rice cropping system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Meinke, H.

    2014-03-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 t ha-1) on the water retention capacity (WRC) of a sandy Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields at 2 and 3 years after application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each t ha-1 of biochar amendment at 2 and 3 years after application. The impact of biochar on soil WRC was most likely related to an increase in overall porosity of the sandy soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5% and 1.6% for each t ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under water limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  10. The effects of long-term aerobic conditioning on +Gz tolerance.

    PubMed

    Whinnery, J E; Parnell, M J

    1987-03-01

    Aerobic conditioning programs for aircrews of high performance fighter type aircraft are very important in assuring optimum fitness and health. The aerobic conditioning resulting from running alters the physiologic state of the individual, and whether or not this alteration affects +Gz tolerance is unknown. In this study, 27 long-term (2 years of running) aerobically conditioned subjects were tested for gradual (1 G x 15 s-1) and rapid onset (1 G x s-1) +Gz tolerance. Maximum VO2 and percent body fat measurements were also performed and correlated to the +Gz-tolerance measurements. Although beneficial for optimum health and fitness, increased aerobic condition (VO2max) resulting from long-term running was not found to enhance +Gz-tolerance. No relationship was observed between aerobic condition and +Gz tolerance. An increased susceptibility to motion sickness was found to be associated with long-term aerobic conditioning. Certain individuals were found to be predisposed to cardiac rate and rhythm disturbances (A-V dissociation and transient asystole) which could potentially alter +Gz-tolerance. Optimum physical conditioning programs for aircrew of fighter aircraft have yet to be determined and implemented. Specificity of exercise training and assurance of the absence of exaggerated cardiovascular response to +Gz stress resulting from physiologic alteration of autonomic tone are critical to the design of optimum conditioning programs for fighter aircraft aircrews. PMID:3579801

  11. Microbial Transformation of 2,4,6-Trinitrotoluene in Aerobic Soil Columns

    PubMed Central

    Bruns-Nagel, D.; Breitung, J.; von Low, E.; Steinbach, K.; Gorontzy, T.; Kahl, M.; Blotevogel, K.; Gemsa, D.

    1996-01-01

    2,4,6-Trinitrotoluene (TNT)-contaminated soil material of a former TNT production plant was percolated aerobically in soil columns. Nineteen days of percolation with a potassium phosphate buffer supplemented with glucose or glucose plus ammonium sulfate caused an over 90% decline in the amount of extractable nitroaromatics in soils containing 70 to 2,100 mg of TNT per kg (dry weight). In the percolation solution, a complete elimination of TNT was achieved. Mutagenicity and soil toxicity were significantly reduced by the percolation process. 4-N-Acetylamino-2-amino-6-nitrotoluene was generated in soil and percolation fluid as a labile TNT metabolite. PMID:16535369

  12. Impact of redox conditions on metolachlor and metribuzin degradation in Mississippi flood plain soils.

    PubMed

    Mulbach, C K; Porthouse, J D; Jugsujinda, A; DeLaune, R D; Johnson, A B

    2000-11-01

    The effect of soil redox conditions on the degradation of metolachlor and metribuzin in two Mississippi soils (Forrestdale silty clay loam and Loring silt loam) were examined in the laboratory. Herbicides were added to soil in microcosms and incubated either under oxidized (aerobic) or reduced (anaerobic) conditions. Metolachlor and metribuzin degradation under aerobic condition in the Forrestdale soil proceeded at rates of 8.83 ngd(-1) and 25 ngd(-1), respectively. Anaerobic degradation rates for the two herbicides in the Forestdale soil were 8.44 ngd(-1) and 32.5 ngd(-1), respectively. Degradation rates for the Loring soil under aerobic condition were 24.8 ngd(-1) and 12.0 ngd(-1) for metolachlor and metribuzin, respectively. Metolachlor and metribuzin degradation rates under anaerobic conditions in the Loring soil were 20.9 ngd(-1) and 5.35 ngd(-1). Metribuzin degraded faster (12.0 ngd(-1)) in the Loring soil under aerobic conditions as compared to anaerobic conditions (5.35 ngd(-1)).

  13. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

    PubMed

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-09-24

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation.

  14. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment

    PubMed Central

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-01-01

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5–10) and temperatures (20–37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation. PMID:27669304

  15. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

    PubMed

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-01-01

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation. PMID:27669304

  16. Chemotactic Motility of Pseudomonas fluorescens F113 under Aerobic and Denitrification Conditions

    PubMed Central

    Redondo-Nieto, Miguel; Rivilla, Rafael; Martín, Marta

    2015-01-01

    The sequence of the genome of Pseudomonas fluorescens F113 has shown the presence of multiple traits relevant for rhizosphere colonization and plant growth promotion. Among these traits are denitrification and chemotactic motility. Besides aerobic growth, F113 is able to grow anaerobically using nitrate and nitrite as final electron acceptors. F113 is able to perform swimming motility under aerobic conditions and under anaerobic conditions when nitrate is used as the electron acceptor. However, nitrite can not support swimming motility. Regulation of swimming motility is similar under aerobic and anaerobic conditions, since mutants that are hypermotile under aerobic conditions, such as gacS, sadB, kinB, algU and wspR, are also hypermotile under anaerobic conditions. However, chemotactic behavior is different under aerobic and denitrification conditions. Unlike most pseudomonads, the F113 genome encode three complete chemotaxis systems, Che1, Che2 and Che3. Mutations in each of the cheA genes of the three Che systems has shown that the three systems are functional and independent. Mutation of the cheA1 gene completely abolished swimming motility both under aerobic and denitrification conditions. Mutation of the cheA2 gene, showed only a decrease in swimming motility under both conditions, indicating that this system is not essential for chemotactic motility but is necessary for optimal motility. Mutation of the cheA3 gene abolished motility under denitrification conditions but only produced a decrease in motility under aerobic conditions. The three Che systems proved to be implicated in competitive rhizosphere colonization, being the cheA1 mutant the most affected. PMID:26161531

  17. Genome Sequence of "Pedosphaera parvula" Ellin514, an Aerobic Verrucomicrobial Isolate from Pasture Soil

    SciTech Connect

    Kant, Ravi; Van Passel, Mark W.J.; Palva, Airi; Lucas, Susan; Copeland, A; Lapidus, Alla L.; Glavina Del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Chertkov, Olga; Larimer, Frank W; Land, Miriam L; Hauser, Loren John; Brettin, Thomas S; Detter, J. Chris; Han, Cliff; De Vos, Willem M.; Janssen, Peter H.; Smidt, Hauke

    2011-01-01

    Pedosphaera parvula Ellin514 is an aerobically grown verrucomicrobial isolate from pasture soil. In contrast to the high abundance of members of Verrucomicrobia subdivision 3 based on molecular surveys in terrestrial environments, Ellin514 is one of the few cultured representatives of this group.

  18. Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

    PubMed Central

    Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

    2013-01-01

    N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway. PMID:24116023

  19. Field assessment of semi-aerobic condition and the methane correction factor for the semi-aerobic landfills provided by IPCC guidelines

    SciTech Connect

    Jeong, Sangjae; Nam, Anwoo; Yi, Seung-Muk; Kim, Jae Young

    2015-02-15

    Highlights: • CH{sub 4}/CO{sub 2} and CH{sub 4} + CO{sub 2}% are proposed as indices to evaluate semi-aerobic landfills. • A landfill which CH{sub 4}/CO{sub 2} > 1.0 is difficult to be categorized as semi-aerobic landfill. • Field conditions should be carefully investigated to determine landfill types. • The MCF default value for semi-aerobic landfills underestimates the methane emissions. - Abstract: According to IPCC guidelines, a semi-aerobic landfill site produces one-half of the amount of CH{sub 4} produced by an equally-sized anaerobic landfill site. Therefore categorizing the landfill type is important on greenhouse gas inventories. In order to assess semi-aerobic condition in the sites and the MCF value for semi-aerobic landfill, landfill gas has been measured from vent pipes in five semi-aerobically designed landfills in South Korea. All of the five sites satisfied requirements of semi-aerobic landfills in 2006 IPCC guidelines. However, the ends of leachate collection pipes which are main entrance of air in the semi-aerobic landfill were closed in all five sites. The CH{sub 4}/CO{sub 2} ratio in landfill gas, indicator of aerobic and anaerobic decomposition, ranged from 1.08 to 1.46 which is higher than the values (0.3–1.0) reported for semi-aerobic landfill sites and is rather close to those (1.0–2.0) for anaerobic landfill sites. The low CH{sub 4} + CO{sub 2}% in landfill gas implied air intrusion into the landfill. However, there was no evidence that air intrusion has caused by semi-aerobic design and operation. Therefore, the landfills investigated in this study are difficult to be classified as semi-aerobic landfills. Also MCF of 0.5 may significantly underestimate methane emissions compared to other researches. According to the carbon mass balance analyses, the higher MCF needs to be proposed for semi-aerobic landfills. Consequently, methane emission estimate should be based on field evaluation for the semi-aerobically designed landfills.

  20. Degradation of vinyl acetate by soil, sewage, sludge, and the newly isolated aerobic bacterium V2.

    PubMed Central

    Nieder, M; Sunarko, B; Meyer, O

    1990-01-01

    Vinyl acetate is subject to microbial degradation in the environment and by pure cultures. It was hydrolyzed by samples of soil, sludge, and sewage at rates of up to 6.38 and 1 mmol/h per g (dry weight) under aerobic and anaerobic conditions, respectively. Four yeasts and thirteen bacteria that feed aerobically on vinyl acetate were isolated. The pathway of vinyl acetate degradation was studied in bacterium V2. Vinyl acetate was degraded to acetate as follows: vinyl acetate + NAD(P)+----2 acetate + NAD(P)H + H+. The acetate was then converted to acetyl coenzyme A and oxidized through the tricarboxylic acid cycle and the glyoxylate bypass. The key enzyme of the pathway is vinyl acetate esterase, which hydrolyzed the ester to acetate and vinyl alcohol. The latter isomerized spontaneously to acetaldehyde and was then converted to acetate. The acetaldehyde was disproportionated into ethanol and acetate. The enzymes involved in the metabolism of vinyl acetate were studied in extracts. Vinyl acetate esterase (Km = 6.13 mM) was also active with indoxyl acetate (Km = 0.98 mM), providing the basis for a convenient spectrophotometric test. Substrates of aldehyde dehydrogenase were formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. The enzyme was equally active with NAD+ or NADP+. Alcohol dehydrogenase was active with ethanol (Km = 0.24 mM), 1-propanol (Km = 0.34 mM), and 1-butanol (Km = 0.16 mM) and was linked to NAD+. The molecular sizes of aldehyde dehydrogenase and alcohol dehydrogenase were 145 and 215 kilodaltons, respectively. PMID:2285314

  1. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils.

    PubMed

    Rigby, H; Smith, S R

    2013-12-01

    Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH4Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application, indicating greater microbial activity in amended soil and reflecting the lower stability of this OM source, compared to the other, anaerobic digestate types, which showed no consistent effects on MBN compared to the control. Thus, the overall net release of digestate N in different soil types was not regulated by N transfer into the soil microbial biomass, but was determined primarily by digestate properties and the capacity of the soil type to process and

  2. Degradation of municipal solid waste in simulated landfill bioreactors under aerobic conditions.

    PubMed

    Slezak, Radoslaw; Krzystek, Liliana; Ledakowicz, Stanislaw

    2015-09-01

    In this study the municipal solid waste degradation processes in simulated landfill bioreactors under aerobic and anaerobic conditions is investigated. The effect of waste aeration on the dynamics of the aerobic degradation processes in lysimeters as well as during anaerobic processes after completion of aeration is presented. The results are compared with the anaerobic degradation process to determine the stabilization stage of waste in both experimental modes. The experiments in aerobic lysimeters were carried out at small aeration rate (4.41⋅10(-3)lmin(-1)kg(-1)) and for two recirculation rates (24.9 and 1.58lm(-3)d(-1)). The change of leachate and formed gases composition showed that the application of even a small aeration rate favored the degradation of organic matter. The amount of CO2 and CH4 released from anaerobic lysimeter was about 5 times lower than that from the aerobic lysimeters. Better stabilization of the waste was obtained in the aerobic lysimeter with small recirculation, from which the amount of CO2 produced was larger by about 19% in comparison with that from the aerobic lysimeter with large leachate recirculation.

  3. Euglena gracilis rhodoquinone:ubiquinone ratio and mitochondrial proteome differ under aerobic and anaerobic conditions.

    PubMed

    Hoffmeister, Meike; van der Klei, Anita; Rotte, Carmen; van Grinsven, Koen W A; van Hellemond, Jaap J; Henze, Katrin; Tielens, Aloysius G M; Martin, William

    2004-05-21

    Euglena gracilis cells grown under aerobic and anaerobic conditions were compared for their whole cell rhodoquinone and ubiquinone content and for major protein spots contained in isolated mitochondria as assayed by two-dimensional gel electrophoresis and mass spectrometry sequencing. Anaerobically grown cells had higher rhodoquinone levels than aerobically grown cells in agreement with earlier findings indicating the need for fumarate reductase activity in anaerobic wax ester fermentation in Euglena. Microsequencing revealed components of complex III and complex IV of the respiratory chain and the E1beta subunit of pyruvate dehydrogenase to be present in mitochondria of aerobically grown cells but lacking in mitochondria from anaerobically grown cells. No proteins were identified as specific to mitochondria from anaerobically grown cells. cDNAs for the E1alpha, E2, and E3 subunits of mitochondrial pyruvate dehydrogenase were cloned and shown to be differentially expressed under aerobic and anaerobic conditions. Their expression patterns differed from that of mitochondrial pyruvate:NADP(+) oxidoreductase, the N-terminal domain of which is pyruvate:ferredoxin oxidoreductase, an enzyme otherwise typical of hydrogenosomes, hydrogen-producing forms of mitochondria found among anaerobic protists. The Euglena mitochondrion is thus a long sought intermediate that unites biochemical properties of aerobic and anaerobic mitochondria and hydrogenosomes because it contains both pyruvate:ferredoxin oxidoreductase and rhodoquinone typical of hydrogenosomes and anaerobic mitochondria as well as pyruvate dehydrogenase and ubiquinone typical of aerobic mitochondria. Our data show that under aerobic conditions Euglena mitochondria are prepared for anaerobic function and furthermore suggest that the ancestor of mitochondria was a facultative anaerobe, segments of whose physiology have been preserved in the Euglena lineage.

  4. Differential Isotopic Fractionation during Cr(VI) Reduction by an Aquifer-Derived Bacterium under Aerobic versus Denitrifying Conditions

    SciTech Connect

    Han, R.; Qin, L.; Brown, S. T.; Christensen, J. N.; Beller, H. R.

    2012-01-27

    We studied Cr isotopic fractionation during Cr(VI) reduction by Pseudomonas stutzeri strain RCH2. Finally, despite the fact that strain RCH2 reduces Cr(VI) cometabolically under both aerobic and denitrifying conditions and at similar specific rates, fractionation was markedly different under these two conditions (ε was ~2‰ aerobically and ~0.4‰ under denitrifying conditions).

  5. An integrated anaerobic/aerobic bioprocess for the remediation of chlorinated phenol-contaminated soil and groundwater.

    PubMed

    Ehlers, George A; Rose, Peter D

    2006-07-01

    An investigation of biodegradation of chlorinated phenol in an anaerobic/aerobic bioprocess environment was made. The reactor configuration used consisted of linked anaerobic and aerobic reactors, which served as a model for a proposed bioremediation strategy. The proposed strategy was studied in two reactors before linkage. In the anaerobic compartment, the transformation of the model contaminant, 2,4,6-trichlorophenol (2,4,6-TCP), to lesser-chlorinated metabolites was shown to occur during reductive dechlorination under sulfate-reducing conditions. The consortium was also shown to desorb and mobilize 2,4,6-TCP in soils. This was followed, in the aerobic compartment, by biodegradation of the pollutant and metabolites, 2,4-dichlorophenol, 4-chlorophenol, and phenol, by immobilized white-rot fungi. The integrated process achieved elimination of the compound by more than 99% through fungal degradation of metabolites produced in the dechlorination stage. pH correction to the anaerobic reactor was found to be necessary because acidic effluent from the fungal reactor inhibited sulfate reduction and dechlorination.

  6. Detoxification of furfural in Corynebacterium glutamicum under aerobic and anaerobic conditions.

    PubMed

    Tsuge, Yota; Hori, Yoshimi; Kudou, Motonori; Ishii, Jun; Hasunuma, Tomohisa; Kondo, Akihiko

    2014-10-01

    The toxic fermentation inhibitors in lignocellulosic hydrolysates raise serious problems for the microbial production of fuels and chemicals. Furfural is considered to be one of the most toxic compounds among these inhibitors. Here, we describe the detoxification of furfural in Corynebacterium glutamicum ATCC13032 under both aerobic and anaerobic conditions. Under aerobic culture conditions, furfuryl alcohol and 2-furoic acid were produced as detoxification products of furfural. The ratio of the products varied depending on the initial furfural concentration. Neither furfuryl alcohol nor 2-furoic acid showed any toxic effect on cell growth, and both compounds were determined to be the end products of furfural degradation. Interestingly, unlike under aerobic conditions, most of the furfural was converted to furfuryl alcohol under anaerobic conditions, without affecting the glucose consumption rate. Both the NADH/NAD(+) and NADPH/NADP(+) ratio decreased in the accordance with furfural concentration under both aerobic and anaerobic conditions. These results indicate the presence of a single or multiple endogenous enzymes with broad and high affinity for furfural and co-factors in C. glutamicum ATCC13032.

  7. Characterization of methanotrophic bacterial populations in natural and agricultural aerobic soils of the European Russia

    NASA Astrophysics Data System (ADS)

    Kravchenko, Irina; Sukhacheva, Marina; Kizilova, Anna

    2014-05-01

    Atmospheric methane contributes to about 20% of the total radiative forcing by long-lived greenhouse gases, and microbial methane oxidation in upland soils is the only biological sink of methane. Microbial methane oxidation in aerated upland soils is estimated as 15 - 45 Tg yr-1 or 3-9% of the annual sink. Therefore there is need of extensive research to characterize methanotrophic activity in various ecosystems for possible application to reduce atmospheric methane fluxes and to minimize global climate change. The vast majority of known aerobic methanotrophs belongs to the Proteobacteria and placed in the families Methylococcaceae in the Gammaproteobacteria, and Methylocystaceae and Beijerinckiaceae in the Alphaproteobacteria. Known exceptions include the phylum Verrucomicrobia and uncultured methanotrophs such as Candidatus 'Methylomirabilis oxyfera' affiliated with the 'NC10' phylum. Plenty of studies of aerobic methane oxidation and key players of the process have been performed on various types of soils, and it was found that Methylocystis spp and uncultivated methanotrophs are abundant in upland soils. Two of the uncultured groups are upland soil cluster alphaproteobacteria (USCa) and gammaproteobacteria (USCg), as revealed by cultivation-independent surveys of pmoA diversity. Russia is extremely rich in soil types due to its vast territories, and most of these soils have never been investigated from the aspect of methanotrophy. This study addresses methane oxidation activity and diversity of aerobic methanotrophic bacteria in eight types of natural aerobic soils, four of which also had been under agricultural use. Methane fluxes have been measured by in situ static chamber method and methane oxidation rates in soil samples - by radioisotope tracer (14CH4) technique. Changes in methanotroph diversity and abundance were assessed by cloning and Sanger sequencing, and quantitative real-time PCR of pmoA genes. Methanotrophic population of unmanaged soils turned

  8. Aerobic biogenesis of selenium nanospheres by Bacillus cereus isolated from coalmine soil

    PubMed Central

    2010-01-01

    Background Microorganisms that are exposed to pollutants in the environment, such as metals/metalloids, have a remarkable ability to fight the metal stress by various mechanisms. These metal-microbe interactions have already found an important role in biotechnological applications. It is only recently that microorganisms have been explored as potential biofactories for synthesis of metal/metalloid nanoparticles. Biosynthesis of selenium (Se0) nanospheres in aerobic conditions by a bacterial strain isolated from the coalmine soil is reported in the present study. Results The strain CM100B, identified as Bacillus cereus by morphological, biochemical and 16S rRNA gene sequencing [GenBank:GU551935.1] was studied for its ability to generate selenium nanoparticles (SNs) by transformation of toxic selenite (SeO32-) anions into red elemental selenium (Se0) under aerobic conditions. Also, the ability of the strain to tolerate high levels of toxic selenite ions was studied by challenging the microbe with different concentrations of sodium selenite (0.5 mM-10 mM). ESEM, AFM and SEM studies revealed the spherical Se0 nanospheres adhering to bacterial biomass as well as present as free particles. The TEM microscopy showed the accumulation of spherical nanostructures as intracellular and extracellular deposits. The deposits were identified as element selenium by EDX analysis. This is also indicated by the red coloration of the culture broth that starts within 2-3 h of exposure to selenite oxyions. Selenium nanoparticles (SNs) were further characterized by UV-Visible spectroscopy, TEM and zeta potential measurement. The size of nanospheres was in the range of 150-200 nm with high negative charge of -46.86 mV. Conclusions This bacterial isolate has the potential to be used as a bionanofactory for the synthesis of stable, nearly monodisperse Se0 nanoparticles as well as for detoxification of the toxic selenite anions in the environment. A hypothetical mechanism for the biogenesis

  9. Nesterenkonia sp. strain F, a halophilic bacterium producing acetone, butanol, and ethanol under aerobic conditions

    PubMed Central

    Amiri, Hamid; Azarbaijani, Reza; Parsa Yeganeh, Laleh; Shahzadeh Fazeli, Abolhassan; Tabatabaei, Meisam; Hosseini Salekdeh, Ghasem; Karimi, Keikhosro

    2016-01-01

    The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol, and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid, and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50, and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid, and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp., and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated. PMID:26725518

  10. Probing the ArcA regulon under aerobic/ROS conditions in Salmonella enterica serovar Typhimurium

    PubMed Central

    2013-01-01

    Background Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS), which is part of the oxidative burst encountered upon internalization of Salmonella enterica serovar Typhimurium (S. Typhimurium) by phagocytic cells. It has previously been established that, the ArcAB two-component system plays a critical role in ROS resistance, but the genes regulated by the system remained undetermined to date. We therefore investigated the ArcA regulon in aerobically growing S. Typhimurium before and after exposure to H2O2 by querying gene expression and other physiological changes in wild type and ΔarcA strains. Results In the ΔarcA strain, expression of 292 genes showed direct or indirect regulation by ArcA in response to H2O2, of which 141were also regulated in aerobiosis, but in the opposite direction. Gene set enrichment analysis (GSEA) of the expression data from WT and ΔarcA strains, revealed that, in response to H2O2 challenge in aerobically grown cells, ArcA down regulated multiple PEP-PTS and ABC transporters, while up regulating genes involved in glutathione and glycerolipid metabolism and nucleotide transport. Further biochemical analysis guided by GSEA results showed that deletion of arcA during aerobic growth lead to increased reactive oxygen species (ROS) production which was concomitant with an increased NADH/NAD+ ratio. In absence of ArcA under aerobic conditions, H2O2 exposure resulted in lower levels of glutathione reductase activity, leading to a decreased GSH (reduced glutathione)/GSSG (oxidized glutathione) ratio. Conclusion The ArcA regulon was defined in 2 conditions, aerobic growth and the combination of peroxide treatment and aerobic growth in S. Typhimurium. ArcA coordinates a response that involves multiple aspects of the carbon flux through central metabolism, which ultimately modulates the reducing potential of the cell. PMID:24044554

  11. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils

    SciTech Connect

    Rigby, H.; Smith, S.R.

    2013-12-15

    Highlights: • Nitrogen release in digestate-amended soil depends on the digestate type. • Overall N release is modulated by digestate mineral and mineralisable N contents. • Microbial immobilisation does not influence overall release of digestate N in soil. • Digestate physical properties and soil type interact to affect overall N recovery. • High labile C inputs in digestate may promote denitrification in fine-textured soil. - Abstract: Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH{sub 4}Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application

  12. 24 CFR 3285.201 - Soil conditions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Soil conditions. 3285.201 Section... DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.201 Soil conditions. To help prevent settling or sagging, the foundation must be constructed on firm, undisturbed soil or...

  13. 24 CFR 3285.201 - Soil conditions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Soil conditions. 3285.201 Section... DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.201 Soil conditions. To help prevent settling or sagging, the foundation must be constructed on firm, undisturbed soil or...

  14. 24 CFR 3285.201 - Soil conditions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Soil conditions. 3285.201 Section... DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.201 Soil conditions. To help prevent settling or sagging, the foundation must be constructed on firm, undisturbed soil or...

  15. 24 CFR 3285.201 - Soil conditions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Soil conditions. 3285.201 Section... DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.201 Soil conditions. To help prevent settling or sagging, the foundation must be constructed on firm, undisturbed soil or...

  16. 24 CFR 3285.201 - Soil conditions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Soil conditions. 3285.201 Section... DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.201 Soil conditions. To help prevent settling or sagging, the foundation must be constructed on firm, undisturbed soil or...

  17. Reductive dechlorination of Tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions.

    PubMed Central

    Kästner, M

    1991-01-01

    Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 mumol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 mumol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 to -150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions. PMID:1892393

  18. P450-catalyzed asymmetric cyclopropanation of electron-deficient olefins under aerobic conditions.

    PubMed

    Renata, Hans; Wang, Z Jane; Kitto, Rebekah Z; Arnold, Frances H

    2014-10-01

    A variant of P450 from Bacillus megaterium five mutations away from wild type is a highly active catalyst for cyclopropanation of a variety of acrylamide and acrylate olefins with ethyl diazoacetate (EDA). The very high rate of reaction enabled by histidine ligation allowed the reaction to be conducted under aerobic conditions. The promiscuity of this catalyst for a variety of substrates containing amides has enabled synthesis of a small library of precursors to levomilnacipran derivatives. PMID:25221671

  19. The effect of cyclic anaerobic-aerobic conditions on biodegradation of azo dyes.

    PubMed

    Yaşar, Semra; Cirik, Kevser; Cinar, Ozer

    2012-03-01

    The effect of cyclic anaerobic-aerobic conditions on the biodegradative capability of the mixed microbial culture for the azo dye Remazol Brilliant Violet 5R (RBV-5R) was investigated in the sequencing batch reactor (SBR) fed with a synthetic textile wastewater. The SBR had a 12-h cycle time with anaerobic-aerobic periods of 3/9, 6/6 and 9/3 h. General SBR performance was assessed by measurement of catabolic enzymes (catechol 2,3-dioxygenase, azo reductase), chemical oxygen demand (COD), color and amount of aromatic amines. In this study, under steady-state conditions, the anaerobic period of the cyclic SBR was found to allow the reductive decolorization of azo dye. Longer anaerobic periods resulted in higher color removal efficiencies, approximately 71% for the 3-h, 87% for 6-h and 92% for the 9-h duration. Total COD removal efficiencies were over 84% under each of the cyclic conditions and increased as the length of the anaerobic period was increased; however, the highest color removal rate was attained for the cycle with the shortest anaerobic period of 3 h. During the decolorization of RBV-5R, two sulfonated aromatic amines (benzene based and naphthalene based) were formed. Additionally, anaerobic azo reductase enzyme was found to be positively affected with the increasing duration of the anaerobic period; however; it was vice versa for the aerobic catechol 2,3-dioxygenase (C23DO) enzyme.

  20. Degradation of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea by nanoscale zerovalent iron under aerobic and anaerobic conditions.

    PubMed

    Lin, Haiying; Hou, Shaogang; Xie, Guohong; Yao, Ziwei; Zhou, Qingxiang

    2012-01-01

    The goal of present study was to investigate the applicability of nanoscale zerovalent iron (NZVI) on the degradation of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea (CCU) under aerobic and anaerobic conditions, respectively. The experimental results showed that NZVI could effectively degrade CCU, but the removal efficiencies were different under these two different conditions. The best removal efficiencies for CCU were 90.2 and 75.8% under aerobic and anaerobic conditions, respectively. The highly oxidative hydroxyl radicals and reductively hydrogen would account for the rapid degradation of CCU under aerobic and anaerobic conditions, respectively. The experimental results also showed that surfactant Tween 20 significantly inhibited the degradation of CCU under aerobic conditions. However it markedly enhanced the degradation of CCU under anaerobic condition.

  1. Aerobic capacity in wild satin bowerbirds: repeatability and effects of age, sex and condition.

    PubMed

    Chappell, Mark A; Savard, Jean-Francois; Siani, Jennifer; Coleman, Seth W; Keagy, Jason; Borgia, Gerald

    2011-10-01

    Individual variation in aerobic capacity has been extensively studied, especially with respect to condition, maturity or pathogen infection, and to gain insights into mechanistic foundations of performance. However, its relationship to mate competition is less well understood, particularly for animals in natural habitats. We examined aerobic capacity [maximum rate of O2 consumption (VO2,max) in forced exercise] in wild satin bowerbirds, an Australian passerine with a non-resource based mating system and strong intermale sexual competition. We tested for repeatability of mass and VO2,max, differences among age and sex classes, and effects of several condition indices. In adult males, we examined interactions between aerobic performance and bower ownership (required for male mating success). There was significant repeatability of mass and VO2,max within and between years, but between-year repeatability was lower than within-year repeatability. VO2,max varied with an overall scaling to mass(0.791), but most variance in VO2,max was not explained by mass. Indicators of condition (tarsus and wing length asymmetry, the ratio of tarsus length to mass) were not correlated to VO2,max. Ectoparasite counts were weakly correlated to VO2,max across all age-sex classes but not within any class. Adult males, the cohort with the most intense levels of mating competition, had higher VO2,max than juvenile birds or adult females. However, there was no difference between the VO2,max of bower-owning males and that of males not known to hold bowers. Thus one major factor determining male reproductive success was not correlated to aerobic performance. PMID:21900466

  2. Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions.

    PubMed

    Benadé, Eliska; Stone, Wendy; Mouton, Marnel; Postma, Ferdinand; Wilsenach, Jac; Botha, Alfred

    2016-04-01

    We used both aerobic and anaerobic liquid co-cultures, prepared with Luria Bertani broth, to study the effect of bacteria on the survival of Candida albicans in the external environment, away from an animal host. The bacteria were represented by Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Clostridium, Enterobacter, Klebsiella pneumoniae, Kluyvera ascorbata and Serratia marcescens. Under aerobic conditions, the yeast's growth was inhibited in the presence of bacterial growth; however, under anaerobic conditions, yeast and bacterial growth in co-cultures was similar to that observed for pure cultures. Subsequent assays revealed that the majority of bacterial strains aerobically produced extracellular hydrolytic enzymes capable of yeast cell wall hydrolysis, including chitinases and mannan-degrading enzymes. In contrast, except for the A. hydrophila strain, these enzymes were not detected in anaerobic bacterial cultures, nor was the antimicrobial compound prodigiosin found in anaerobic cultures of S. marcescens. When we suspended C. albicans cells in crude extracellular enzyme preparations from K. pneumoniae and S. marcescens, we detected no negative effect on yeast viability. However, we found that these preparations enhance the toxicity of prodigiosin towards the yeast, especially in combination with mannan-degrading enzymes. Analyses of the chitin and mannan content of yeast cell walls revealed that less chitin was produced under anaerobic than aerobic conditions; however, the levels of mannan, known for its low permeability, remained the same. The latter phenomenon, as well as reduced production of the bacterial enzymes and prodigiosin, may contribute to anaerobic growth and survival of C. albicans in the presence of bacteria.

  3. Binary Interactions of Antagonistic Bacteria with Candida albicans Under Aerobic and Anaerobic Conditions.

    PubMed

    Benadé, Eliska; Stone, Wendy; Mouton, Marnel; Postma, Ferdinand; Wilsenach, Jac; Botha, Alfred

    2016-04-01

    We used both aerobic and anaerobic liquid co-cultures, prepared with Luria Bertani broth, to study the effect of bacteria on the survival of Candida albicans in the external environment, away from an animal host. The bacteria were represented by Aeromonas hydrophila, Bacillus cereus, Bacillus subtilis, Clostridium, Enterobacter, Klebsiella pneumoniae, Kluyvera ascorbata and Serratia marcescens. Under aerobic conditions, the yeast's growth was inhibited in the presence of bacterial growth; however, under anaerobic conditions, yeast and bacterial growth in co-cultures was similar to that observed for pure cultures. Subsequent assays revealed that the majority of bacterial strains aerobically produced extracellular hydrolytic enzymes capable of yeast cell wall hydrolysis, including chitinases and mannan-degrading enzymes. In contrast, except for the A. hydrophila strain, these enzymes were not detected in anaerobic bacterial cultures, nor was the antimicrobial compound prodigiosin found in anaerobic cultures of S. marcescens. When we suspended C. albicans cells in crude extracellular enzyme preparations from K. pneumoniae and S. marcescens, we detected no negative effect on yeast viability. However, we found that these preparations enhance the toxicity of prodigiosin towards the yeast, especially in combination with mannan-degrading enzymes. Analyses of the chitin and mannan content of yeast cell walls revealed that less chitin was produced under anaerobic than aerobic conditions; however, the levels of mannan, known for its low permeability, remained the same. The latter phenomenon, as well as reduced production of the bacterial enzymes and prodigiosin, may contribute to anaerobic growth and survival of C. albicans in the presence of bacteria. PMID:26566932

  4. Antimicrobial Susceptibility of Enteric Gram Negative Facultative Anaerobe Bacilli in Aerobic versus Anaerobic Conditions

    PubMed Central

    Amachawadi, Raghavendra G.; Renter, David G.; Volkova, Victoriya V.

    2016-01-01

    Antimicrobial treatments result in the host’s enteric bacteria being exposed to the antimicrobials. Pharmacodynamic models can describe how this exposure affects the enteric bacteria and their antimicrobial resistance. The models utilize measurements of bacterial antimicrobial susceptibility traditionally obtained in vitro in aerobic conditions. However, in vivo enteric bacteria are exposed to antimicrobials in anaerobic conditions of the lower intestine. Some of enteric bacteria of food animals are potential foodborne pathogens, e.g., Gram-negative bacilli Escherichia coli and Salmonella enterica. These are facultative anaerobes; their physiology and growth rates change in anaerobic conditions. We hypothesized that their antimicrobial susceptibility also changes, and evaluated differences in the susceptibility in aerobic vs. anaerobic conditions of generic E. coli and Salmonella enterica of diverse serovars isolated from cattle feces. Susceptibility of an isolate was evaluated as its minimum inhibitory concentration (MIC) measured by E-Test® following 24 hours of adaptation to the conditions on Mueller-Hinton agar, and on a more complex tryptic soy agar with 5% sheep blood (BAP) media. We considered all major antimicrobial drug classes used in the U.S. to treat cattle: β-lactams (specifically, ampicillin and ceftriaxone E-Test®), aminoglycosides (gentamicin and kanamycin), fluoroquinolones (enrofloxacin), classical macrolides (erythromycin), azalides (azithromycin), sulfanomides (sulfamethoxazole/trimethoprim), and tetracyclines (tetracycline). Statistical analyses were conducted for the isolates (n≥30) interpreted as susceptible to the antimicrobials based on the clinical breakpoint interpretation for human infection. Bacterial susceptibility to every antimicrobial tested was statistically significantly different in anaerobic vs. aerobic conditions on both media, except for no difference in susceptibility to ceftriaxone on BAP agar. A satellite experiment

  5. Antimicrobial Susceptibility of Enteric Gram Negative Facultative Anaerobe Bacilli in Aerobic versus Anaerobic Conditions.

    PubMed

    DeMars, Zachary; Biswas, Silpak; Amachawadi, Raghavendra G; Renter, David G; Volkova, Victoriya V

    2016-01-01

    Antimicrobial treatments result in the host's enteric bacteria being exposed to the antimicrobials. Pharmacodynamic models can describe how this exposure affects the enteric bacteria and their antimicrobial resistance. The models utilize measurements of bacterial antimicrobial susceptibility traditionally obtained in vitro in aerobic conditions. However, in vivo enteric bacteria are exposed to antimicrobials in anaerobic conditions of the lower intestine. Some of enteric bacteria of food animals are potential foodborne pathogens, e.g., Gram-negative bacilli Escherichia coli and Salmonella enterica. These are facultative anaerobes; their physiology and growth rates change in anaerobic conditions. We hypothesized that their antimicrobial susceptibility also changes, and evaluated differences in the susceptibility in aerobic vs. anaerobic conditions of generic E. coli and Salmonella enterica of diverse serovars isolated from cattle feces. Susceptibility of an isolate was evaluated as its minimum inhibitory concentration (MIC) measured by E-Test® following 24 hours of adaptation to the conditions on Mueller-Hinton agar, and on a more complex tryptic soy agar with 5% sheep blood (BAP) media. We considered all major antimicrobial drug classes used in the U.S. to treat cattle: β-lactams (specifically, ampicillin and ceftriaxone E-Test®), aminoglycosides (gentamicin and kanamycin), fluoroquinolones (enrofloxacin), classical macrolides (erythromycin), azalides (azithromycin), sulfanomides (sulfamethoxazole/trimethoprim), and tetracyclines (tetracycline). Statistical analyses were conducted for the isolates (n≥30) interpreted as susceptible to the antimicrobials based on the clinical breakpoint interpretation for human infection. Bacterial susceptibility to every antimicrobial tested was statistically significantly different in anaerobic vs. aerobic conditions on both media, except for no difference in susceptibility to ceftriaxone on BAP agar. A satellite experiment

  6. The preferential growth of branched GDGT source microorganisms under aerobic conditions in peat revealed by stable isotope probing experiments

    NASA Astrophysics Data System (ADS)

    Huguet, Arnaud; Meador, Travis B.; Laggoun-Défarge, Fatima; Könneke, Martin; Derenne, Sylvie; Hinrichs, Kai-Uwe

    2016-04-01

    Branched glycerol dialkyl glycerol tetraether (brGDGTs) membrane lipids are widely distributed in aquatic and terrestrial environments and are being increasingly used as temperature proxies. Nevertheless, little is known regarding the microorganisms that produce these lipids, which are found in especially high abundance in the anaerobic horizons of peat bogs. We initiated stable isotope probing incubations of peat samples from a Sphagnum-dominated peatland (Jura Mountains, France) to measure the incorporation of (D)-D2O and 13C-labeled dissolved inorganic carbon (DIC) into brGDGTs, and thus gauge the activity, growth, and turnover times of their source organisms. Peat samples were collected from two adjacent sites with contrasting humidity levels (hereafter called "fen" and "bog" sites). For each site, samples from the surficial aerobic layer (acrotelm) and deeper anaerobic layer (catotelm) were collected and were incubated under both anaerobic and aerobic conditions for the acrotelm samples and only anaerobic conditions for the catotelm. The incubations were performed at 12 ° C, consistent with the mean summer air temperature at the sampling site. After two months of incubation, there was no incorporation of 13C label in brGDGTs for samples incubated under either aerobic or anaerobic conditions, showing that brGDGT-producing bacteria are heterotrophic microorganisms, as previously observed in organo-mineral soils (Weijers et al., 2011). Similarly, little to no deuterium incorporation was observed for brGDGTs isolated from anaerobically-incubated deep samples. In contrast, in the aerobic incubations of acrotelm samples from bog and fen, the weighted average δD of brGDGT core lipids (CLs) increased by up to 3332‰ and 933‰ after two months, respectively, indicating that fresh brGDGT CLs were biosynthesized at the peat surface. D incorporation into brGDGT CLs converted to production rates ranging from 30-106 ng cm-3y-1 in the aerobic acrotelm from bog and fen

  7. The preferential growth of branched GDGT source microorganisms under aerobic conditions in peat revealed by stable isotope probing experiments

    NASA Astrophysics Data System (ADS)

    Huguet, Arnaud; Meador, Travis B.; Laggoun-Défarge, Fatima; Könneke, Martin; Derenne, Sylvie; Hinrichs, Kai-Uwe

    2016-04-01

    Branched glycerol dialkyl glycerol tetraether (brGDGTs) membrane lipids are widely distributed in aquatic and terrestrial environments and are being increasingly used as temperature proxies. Nevertheless, little is known regarding the microorganisms that produce these lipids, which are found in especially high abundance in the anaerobic horizons of peat bogs. We initiated stable isotope probing incubations of peat samples from a Sphagnum-dominated peatland (Jura Mountains, France) to measure the incorporation of (D)-D2O and 13C-labeled dissolved inorganic carbon (DIC) into brGDGTs, and thus gauge the activity, growth, and turnover times of their source organisms. Peat samples were collected from two adjacent sites with contrasting humidity levels (hereafter called "fen" and "bog" sites). For each site, samples from the surficial aerobic layer (acrotelm) and deeper anaerobic layer (catotelm) were collected and were incubated under both anaerobic and aerobic conditions for the acrotelm samples and only anaerobic conditions for the catotelm. The incubations were performed at 12 ° C, consistent with the mean summer air temperature at the sampling site. After two months of incubation, there was no incorporation of 13C label in brGDGTs for samples incubated under either aerobic or anaerobic conditions, showing that brGDGT-producing bacteria are heterotrophic microorganisms, as previously observed in organo-mineral soils (Weijers et al., 2011). Similarly, little to no deuterium incorporation was observed for brGDGTs isolated from anaerobically-incubated deep samples. In contrast, in the aerobic incubations of acrotelm samples from bog and fen, the weighted average δD of brGDGT core lipids (CLs) increased by up to 3332‰ and 933‰ after two months, respectively, indicating that fresh brGDGT CLs were biosynthesized at the peat surface. D incorporation into brGDGT CLs converted to production rates ranging from 30-106 ng cm‑3y‑1 in the aerobic acrotelm from bog and

  8. Biochar increases plant-available water in a sandy loam soil under an aerobic rice crop system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Marimon, B. H., Jr.; Meinke, H.

    2014-09-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha-1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha-1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  9. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

    PubMed

    Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

    2013-02-01

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition. PMID:23202642

  10. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

    PubMed

    Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

    2013-02-01

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition.

  11. Fate of aerobic bacterial granules with fungal contamination under different organic loading conditions.

    PubMed

    Li, An-jie; Zhang, Tong; Li, Xiao-yan

    2010-01-01

    Aerobic sludge granulation is an attractive new technology for biological wastewater treatment. However, the instability of aerobic granules caused by fungal growth is still one of the main problems encountered in granular bioreactors. In this study, laboratory experiments were conducted to investigate the fate and transformation of aerobic granules under different organic loading conditions. Bacterial granules (2-3mm) in a poor condition with fungi-like black filamentous growth were seeded into two 1L batch reactors. After more than 100d of cultivation, the small seed granules in the two reactors had grown into two different types of large granules (>20mm) with different and unique morphological features. In reactor R1 with a high organic loading rate of 2.0g COD L(-1)d(-1), the black filaments mostly disappeared from the granules, and the dominance of rod-shaped bacteria was recovered. In contrast, at a low loading of 0.5g COD L(-1)d(-1) in reactor R2, the filaments eventually became dominant in the black fungal granules. The bacteria in R1 granules had a unique web-like structure with large pores of a few hundred microm in size, which would allow for effective substrate and oxygen transport into the interior of the granules. DNA-based molecular analysis indicated the evolution of the bacterial population in R1 and that of the eukaryal community in R2. The experimental results suggest that a high loading rate can be an effective means of helping to control fungal bloom, recover bacterial domination and restore the stability of aerobic granules that suffer from fungal contamination.

  12. Modeling of yeast Brettanomyces bruxellensis growth at different acetic acid concentrations under aerobic and anaerobic conditions.

    PubMed

    Yahara, Garcia Alvarado; Javier, Mendez Ancona; Tulio, Mata Jimenez Marco; Javier, Gómez Rodriguez; Guadalupe, Aguilar Uscanga Maria

    2007-11-01

    Glucose utilization by Brettanomyces bruxellensis at different acetic acid concentrations under aerobic and anaerobic conditions was investigated. The presence of the organic acid disturbs the growth and fermentative activity of the yeast when its concentration exceeds 2 g l(-1). A mathematical model is proposed for the kinetic behavior analysis of yeast growing in batch culture. A Matlab algorithm was used for estimation of model parameters, whose confidence intervals were also calculated at a 0.95 probability level using a t-Student distribution for f degrees of freedom. The model successfully simulated the batch kinetics observed at different concentrations of acetic acid under both oxygen conditions.

  13. Aerobic biodegradation of biphenyl and polychlorinated biphenyls by Arctic soil microorganisms.

    PubMed Central

    Mohn, W W; Westerberg, K; Cullen, W R; Reimer, K J

    1997-01-01

    We examined the degradation of biphenyl and the commercial polychlorinated biphenyl (PCB) mixture Aroclor 1221 by indigenous Arctic soil microorganisms to assess both the response of the soil microflora to PCB pollution and the potential of the microflora for bioremediation. In soil slurries, Arctic soil microflora and temperate-soil microflora had similar potentials to mineralize [14C]biphenyl. Mineralization began sooner and was more extensive in slurries of PCB-contaminated Arctic soils than in slurries of uncontaminated Arctic soils. The maximum mineralization rates at 30 and 7 degrees C were typically 1.2 to 1.4 and 0.52 to 1.0 mg of biphenyl g of dry soil-1 day-1, respectively. Slurries of PCB-contaminated Arctic soils degraded Aroclor 1221 more extensively at 30 degrees C (71 to 76% removal) than at 7 degrees C (14 to 40% removal). We isolated from Arctic soils organisms that were capable of psychrotolerant (growing at 7 to 30 degrees C) or psychrophilic (growing at 7 to 15 degrees C) growth on biphenyl. Two psychrotolerant isolates extensively degraded Aroclor 1221 at 7 degrees C (54 to 60% removal). The soil microflora and psychrotolerant isolates degraded all mono-, most di-, and some trichlorobiphenyl congeners. The results suggest that PCB pollution selected for biphenyl-mineralizing microorganisms in Arctic soils. While low temperatures severely limited Aroclor 1221 removal in slurries of Arctic soils, results with pure cultures suggest that more effective PCB biodegradation is possible under appropriate conditions. PMID:9292988

  14. Biodegradation of methyl t-butyl ether by aerobic granules under a cosubstrate condition.

    PubMed

    Zhang, L L; Chen, J M; Fang, F

    2008-03-01

    Aerobic granules efficient at degrading methyl tert-butyl ether (MTBE) with ethanol as a cosubstrate were successfully developed in a well-mixed sequencing batch reactor (SBR). Aerobic granules were first observed about 100 days after reactor startup. Treatment efficiency of MTBE in the reactor during stable operation exceeded 99.9%, and effluent MTBE was in the range of 15-50 microg/L. The specific MTBE degradation rate was observed to increase with increasing MTBE initial concentration from 25 to 500 mg/L, which peaked at 22.7 mg MTBE/g (volatile suspended solids).h and declined with further increases in MTBE concentration as substrate inhibition effects became significant. Microbial-community deoxyribonucleic acid profiling was carried out using denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal ribonucleic acid. The reactor was found to be inhabited by several diverse bacterial species, most notably microorganisms related to the genera Sphingomonas, Methylobacterium, and Hyphomicrobium vulgare. These organisms were previously reported to be associated with MTBE biodegradation. A majority of the bands in the reactor represented a group of organisms belonging to the Flavobacteria-Proteobacteria-Actinobacteridae class of bacteria. This study demonstrates that MTBE can be effectively degraded by aerobic granules under a cosubstrate condition and gives insight into the microorganisms potentially involved in the process. PMID:18183384

  15. Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

    PubMed Central

    2014-01-01

    Background Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. Results A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. Conclusions C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction. PMID:25098921

  16. Comparison of Proteomics Profiles of Campylobacter jejuni Strain Bf under Microaerobic and Aerobic Conditions

    PubMed Central

    Rodrigues, Ramila C.; Haddad, Nabila; Chevret, Didier; Cappelier, Jean-Michel; Tresse, Odile

    2016-01-01

    Campylobacter jejuni accounts for one of the leading causes of foodborne bacterial enteritis in humans. Despite being considered an obligate microaerobic microorganism, C. jejuni is regularly exposed to oxidative stress. However, its adaptive strategies to survive the atmospheric oxygen level during transmission to humans remain unclear. Recently, the clinical C. jejuni strain Bf was singled out for its unexpected ability to grow under ambient atmosphere. Here, we aimed to understand better the biological mechanisms underlying its atypical aerotolerance trait using two-dimensional protein electrophoresis, gene expression, and enzymatic activities. Forty-seven proteins were identified with a significantly different abundance between cultivation under microaerobic and aerobic conditions. The over-expressed proteins in aerobiosis belonged mainly to the oxidative stress response, enzymes of the tricarboxylic acid cycle, iron uptake, and regulation, and amino acid uptake when compared to microaerobic conditions. The higher abundance of proteins related to oxidative stress was correlated to dramatically higher transcript levels of the corresponding encoding genes in aerobic conditions compared to microaerobic conditions. In addition, a higher catalase-equivalent activity in strain Bf was observed. Despite the restricted catabolic capacities of C. jejuni, this study reveals that strain Bf is equipped to withstand oxidative stress. This ability could contribute to emergence and persistence of particular strains of C. jejuni throughout food processing or macrophage attack during human infection. PMID:27790195

  17. Aerobic Conditioning Might Protect Against Liver and Muscle Injury Caused by Short-Term Military Training.

    PubMed

    Koury, Josely C; Daleprane, Julio B; Pitaluga-Filho, Mario V; de Oliveira, Cyntia F; Gonçalves, Mariana C; Passos, Magna C F

    2016-02-01

    This study aimed to compare the biochemical markers of muscle and liver injury and total antioxidant capacity in army cadets after a traditional army physical training program and to correlate these effects with aerobic conditioning. Male army cadets (n = 87; age, 20 ± 2 years) were evaluated 12 hours before the start of training (T0), 12 hours after a 30-km march (T1), and 48 hours after military training (T2). Creatine kinase (CK), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) serum levels were measured using an autoanalyzer. Total antioxidant capacity was determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (Sc%). Seventy-four percent of army cadets were classified as having excellent aerobic conditioning (53.9 ± 3.0 ml · kg(-) · min(-1) predicted VO2max from the Cooper test). The median serum concentration of all enzymes increased 12 hours after marching (T1: CK 675%; ALT 59%; AST 336%; AST/ALT ratio 85%; p = 0.001) and 48 hours after the end of training (T2: CK 878%; ALT 256%; AST 418%; AST/ALT ratio 180%; p = 0.001). Sc% was higher in T2 (31.1 ± 9.8%; p = 0.01) than in T0 (3.4% change). Maximal oxygen consumption (ml · kg(-1) · min(-1)) correlated negatively with CK (r = -0.25; p = 0.009) and ALT (r = -0.21; p = 0.03) serum levels, and positively with the change in Sc% (r = 0.22; p = 0.04) at T2. The results indicate that intense military training can cause liver and muscle injury and that aerobic conditioning can be considered as a protective factor for these injuries. PMID:26813633

  18. Impact of oxidative stress defense on bacterial survival and morphological change in Campylobacter jejuni under aerobic conditions.

    PubMed

    Oh, Euna; McMullen, Lynn; Jeon, Byeonghwa

    2015-01-01

    Campylobacter jejuni, a microaerophilic foodborne pathogen, inescapably faces high oxygen tension during its transmission to humans. Thus, the ability of C. jejuni to survive under oxygen-rich conditions may significantly impact C. jejuni viability in food and food safety as well. In this study, we investigated the impact of oxidative stress resistance on the survival of C. jejuni under aerobic conditions by examining three mutants defective in key antioxidant genes, including ahpC, katA, and sodB. All the three mutants exhibited growth reduction under aerobic conditions compared to the wild-type (WT), and the ahpC mutant showed the most significant growth defect. The CFU reduction in the mutants was recovered to the WT level by complementation. Higher levels of reactive oxygen species were accumulated in C. jejuni under aerobic conditions than microaerobic conditions, and supplementation of culture media with an antioxidant recovered the growth of C. jejuni. The levels of lipid peroxidation and protein oxidation were significantly increased in the mutants compared to WT. Additionally, the mutants exhibited different morphological changes under aerobic conditions. The ahpC and katA mutants developed coccoid morphology by aeration, whereas the sodB mutant established elongated cellular morphology. Compared to microaerobic conditions, interestingly, aerobic culture conditions substantially induced the formation of coccoidal cells, and antioxidant treatment reduced the emergence of coccoid forms under aerobic conditions. The ATP concentrations and PMA-qPCR analysis supported that oxidative stress is a factor that induces the development of a viable-but-non-culturable state in C. jejuni. The findings in this study clearly demonstrated that oxidative stress resistance plays an important role in the survival and morphological changes of C. jejuni under aerobic conditions. PMID:25914692

  19. Changes in Soil Minerology Reduce Phosphorus Mobility During Anoxic Soil Conditions

    NASA Astrophysics Data System (ADS)

    Giri, S. K.; Geohring, L. D.; Richards, B. K.; Walter, M.; Steenhuis, T. S.

    2008-05-01

    soil incubation showed higher P sorption than aerobic soil due to reduced iron (Fe+2) - P mineral formation. Some of the readily available P in the soil solution tended to co-precipitate quickly with Fe, Al, Ca, and Mn, but it also resulted in the formation of earthy masses of vivianite [Fe2+3(PO4)2 . 8 H20], thus almost completely immobilizing P. These findings suggest that where conditions in the landscape are saturated, but remain stagnant for extended time periods, P additions may not necessarily enhance leaching once hydrological transport resumes. The temporal nature of P mobilization processes combined with rapid (i.e., preferential flow) hydrological transport appears to have a more important role in controlling P transport through the landscape.

  20. Bioremediation of endosulfan contaminated soil and water -- optimization of operating conditions in laboratory scale reactors.

    PubMed

    Kumar, Mathava; Philip, Ligy

    2006-08-21

    A mixed bacterial culture consisted of Staphylococcus sp., Bacillus circulans-I and -II has been enriched from contaminated soil collected from the vicinity of an endosulfan processing industry. The degradation of endosulfan by mixed bacterial culture was studied in aerobic and facultative anaerobic conditions via batch experiments with an initial endosulfan concentration of 50mg/L. After 3 weeks of incubation, mixed bacterial culture was able to degrade 71.58+/-0.2% and 75.88+/-0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively. The addition of external carbon (dextrose) increased the endosulfan degradation in both the conditions. The optimal dextrose concentration and inoculum size was estimated as 1g/L and 75mg/L, respectively. The pH of the system has significant effect on endosulfan degradation. The degradation of alpha endosulfan was more compared to beta endosulfan in all the experiments. Endosulfan biodegradation in soil was evaluated by miniature and bench scale soil reactors. The soils used for the biodegradation experiments were identified as clayey soil (CL, lean clay with sand), red soil (GM, silty gravel with sand), sandy soil (SM, silty sand with gravel) and composted soil (PT, peat) as per ASTM (American society for testing and materials) standards. Endosulfan degradation efficiency in miniature soil reactors were in the order of sandy soil followed by red soil, composted soil and clayey soil in both aerobic and anaerobic conditions. In bench scale soil reactors, endosulfan degradation was observed more in the bottom layers. After 4 weeks, maximum endosulfan degradation efficiency of 95.48+/-0.17% was observed in red soil reactor where as in composted soil-I (moisture 38+/-1%) and composted soil-II (moisture 45+/-1%) it was 96.03+/-0.23% and 94.84+/-0.19%, respectively. The high moisture content in compost soil reactor-II increased the endosulfan concentration in the leachate. Known intermediate metabolites of

  1. Silicification-induced cell aggregation for the sustainable production of H2 under aerobic conditions.

    PubMed

    Xiong, Wei; Zhao, Xiaohong; Zhu, Genxing; Shao, Changyu; Li, Yaling; Ma, Weimin; Xu, Xurong; Tang, Ruikang

    2015-10-01

    Photobiological hydrogen production is of great importance because of its promise for generating clean renewable energy. In nature, green algae cannot produce hydrogen as a result of the extreme sensitivity of hydrogenase to oxygen. However, we find that silicification-induced green algae aggregates can achieve sustainable photobiological hydrogen production even under natural aerobic conditions. The core-shell structure of the green algae aggregates creates a balance between photosynthetic electron generation and hydrogenase activity, thus allowing the production of hydrogen. This finding provides a viable pathway for the solar-driven splitting of water into hydrogen and oxygen to develop green energy alternatives by using rationally designed cell-material complexes.

  2. Transformation of (14)C-pyrimidynyloxybenzoic herbicide ZJ0273 in aerobic soils.

    PubMed

    Haiyan, Wang; Zhiyang, Yu; Ling, Yue; Ailiang, Han; Yanfei, Zhang; Juying, Li; Qingfu, Ye; Zhengmin, Yang; Long, Lu

    2010-04-15

    A soil metabolism study of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate (ZJ0273), a novel broad-spectrum herbicide, was carried out using (14)C labeled on two different rings, i.e., [pyrimidine-4,6-(14)C] ZJ0273 and [benzyl-U-(14)C] ZJ0273. Ultralow liquid scintillation counting and LC-MS/MS were used to identify the degradation intermediates and quantify their dynamics in aerobic soils. Four aromatic intermediates, 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoic acid (M1), 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzamido)benzoic acid (M2), 2-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M3), and 4,6-dimethoxypyrimidin-2-ol (M4), were identified and their identity was further confirmed against authentic standards. Analysis of metabolites suggested two degradation pathways: (1) Upon loss of the propyl group, M1 was produced via hydrolysis of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate after which the C-N bond between rings A and B was cleaved by oxidation and biochemical degradation to yield M3, which was further converted into M4 and finally mineralized to CO(2); and (2) the first step was the same as in pathway 1, but M1 first underwent a carbonylation to form M2. The C-N bond between rings A and B of M2 was cleaved by hydrolysis to yield M3. Dynamic changes in the four metabolites in aerobic soils were also investigated by HPLC coupled analysis of radioactivity of isolated peaks. After a 100-day incubation, 1.7-9.7% of applied (14)C was found as M1, 0.3-1.1% as M2, 14.5-20.9% as M3, and 3.7-6.7% as M4 in the soils, and pH appeared to be the most influential soil property affecting the formation and dissipation of these metabolites.

  3. Biodegradability of biodegradable/degradable plastic materials under aerobic and anaerobic conditions.

    PubMed

    Mohee, R; Unmar, G D; Mudhoo, A; Khadoo, P

    2008-01-01

    A study was conducted on two types of plastic materials, Mater-Bi Novamont (MB) and Environmental Product Inc. (EPI), to assess their biodegradability under aerobic and anaerobic conditions. For aerobic conditions, organic fractions of municipal solid wastes were composted. For the anaerobic process, anaerobic inoculum from a wastewater treatment plant was used. Cellulose filter papers (CFP) were used as a positive control for both mediums. The composting process was monitored in terms of temperature, moisture and volatile solids and the biodegradation of the samples were monitored in terms of mass loss. Monitoring results showed a biodegradation of 27.1% on a dry basis for MB plastic within a period of 72 days of composting. Biodegradability under an anaerobic environment was monitored in terms of biogas production. A cumulative methane gas production of 245 ml was obtained for MB, which showed good degradation as compared to CFP (246.8 ml). However, EPI plastic showed a cumulative methane value of 7.6 ml for a period of 32 days, which was close to the blank (4.0 ml). The EPI plastic did not biodegrade under either condition. The cumulative carbon dioxide evolution after 32 days was as follows: CFP 4.406 cm3, MB 2.198 cm3 and EPI 1.328 cm3. The cumulative level of CO2 varying with time fitted sigmoid type curves with R2 values of 0.996, 0.996 and 0.995 for CFP, MB and EPI, respectively.

  4. Antibacterial Action of Nitric Oxide-Releasing Chitosan Oligosaccharides against Pseudomonas aeruginosa under Aerobic and Anaerobic Conditions

    PubMed Central

    Reighard, Katelyn P.

    2015-01-01

    Chitosan oligosaccharides were modified with N-diazeniumdiolates to yield biocompatible nitric oxide (NO) donor scaffolds. The minimum bactericidal concentrations and MICs of the NO donors against Pseudomonas aeruginosa were compared under aerobic and anaerobic conditions. Differential antibacterial activities were primarily the result of NO scavenging by oxygen under aerobic environments and not changes in bacterial physiology. Bacterial killing was also tested against nonmucoid and mucoid biofilms and compared to that of tobramycin. Smaller NO payloads were required to eradicate P. aeruginosa biofilms under anaerobic versus aerobic conditions. Under oxygen-free environments, the NO treatment was 10-fold more effective at killing biofilms than tobramycin. These results demonstrate the potential utility of NO-releasing chitosan oligosaccharides under both aerobic and anaerobic environments. PMID:26239983

  5. Effect of passivator on Cu form transformation in pig manure aerobic composting and application in soil.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun; Zhang, Hui; Fu, Jie

    2015-10-01

    A sequential extraction approach was used to evaluate the effects of various combinations of passivators (sepiolite, phosphate rock, and coal fly ash) on the concentration and speciation of Cu in swine manure aerobic compost along with soil to which the compost had been applied. The results indicate that the various passivators altered the bound forms of Cu in pig manure and soil; the concentrations of exchangeable and Fe-Mn-bound Cu decreased, whereas the residual Cu concentration increased, indicating that Cu transformed to low-availability forms after the passivator treatments. The concentrations of the carbonate-bound and organic-bound Cu varied widely. Among all treatments, the treatment of the control + straw + sepiolite + coal fly ash (2.5 %) + phosphate rock (5.0 %) resulted in the most efficient passivation of Cu; the percentage of residual Cu reached 3.91-21.14 %, obviously surpassing the percentage for the control without passivation. The treatment of the control + straw + sepiolite + phosphate rock (2.5 %) resulted in the lowest residual Cu fraction (0.85 %) among passivator treatments. These results show that the addition of suitable combinations of passivators to the composting process reduced the availability of Cu and the risk of Cu pollution during the application of composted pig manure to soil. Passivation also decreased the Cu content of Apium graveolens.

  6. Effect of passivator on Cu form transformation in pig manure aerobic composting and application in soil.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun; Zhang, Hui; Fu, Jie

    2015-10-01

    A sequential extraction approach was used to evaluate the effects of various combinations of passivators (sepiolite, phosphate rock, and coal fly ash) on the concentration and speciation of Cu in swine manure aerobic compost along with soil to which the compost had been applied. The results indicate that the various passivators altered the bound forms of Cu in pig manure and soil; the concentrations of exchangeable and Fe-Mn-bound Cu decreased, whereas the residual Cu concentration increased, indicating that Cu transformed to low-availability forms after the passivator treatments. The concentrations of the carbonate-bound and organic-bound Cu varied widely. Among all treatments, the treatment of the control + straw + sepiolite + coal fly ash (2.5 %) + phosphate rock (5.0 %) resulted in the most efficient passivation of Cu; the percentage of residual Cu reached 3.91-21.14 %, obviously surpassing the percentage for the control without passivation. The treatment of the control + straw + sepiolite + phosphate rock (2.5 %) resulted in the lowest residual Cu fraction (0.85 %) among passivator treatments. These results show that the addition of suitable combinations of passivators to the composting process reduced the availability of Cu and the risk of Cu pollution during the application of composted pig manure to soil. Passivation also decreased the Cu content of Apium graveolens. PMID:25982987

  7. Novel aerobic benzene degrading microorganisms identified in three soils by stable isotope probing.

    PubMed

    Xie, Shuguang; Sun, Weimin; Luo, Chunling; Cupples, Alison M

    2011-02-01

    The remediation of benzene contaminated groundwater often involves biodegradation and although the mechanisms of aerobic benzene biodegradation in laboratory cultures have been well studied, less is known about the microorganisms responsible for benzene degradation in mixed culture samples or at contaminated sites. To address this knowledge gap, DNA based stable isotope probing (SIP) was utilized to identify active benzene degraders in microcosms constructed with soil from three sources (a contaminated site and two agricultural sites). For this, replicate microcosms were amended with either labeled (¹³C) or unlabeled benzene and the extracted DNA samples were ultracentrifuged, fractioned and subject to terminal restriction fragment length polymorphism (TRFLP). The dominant benzene degraders (responsible for ¹³C uptake) were determined by comparing relative abundance of TRFLP phylotypes in heavy fractions of labeled benzene (¹³C) amended samples to the controls (from unlabeled benzene amended samples). Two phylotypes (a Polaromonas sp. and an Acidobacterium) were the major benzene degraders in the microcosms constructed from the contaminated site soil, whereas one phylotype incorporated the majority of the benzene-derived ¹³C in each of the agricultural soils ("candidate" phylum TM7 and an unclassified Sphingomonadaceae).

  8. America's Soil and Water: Condition and Trends.

    ERIC Educational Resources Information Center

    1981

    A review of conditions and trends regarding soil and water resources of rural nonfederal lands of the United States is presented in this publication. Maps, charts, and graphs illustrate the data collected on various aspects of soil and water use and practice. Topic areas considered include: (1) land use patterns; (2) classes of land; (3)…

  9. Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions.

    PubMed

    Jahren, Sigrun J; Rintala, Jukka A; Odegaard, Hallvard

    2002-02-01

    The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards. During the 107 days of experiment, the 60-65% SCOD removals were achieved at organic loading rates of 2.5-3.5 kg SCODm(-3) d(-1), the highest loading rates applied during the run and HRT of 13-22h. Carbohydrates, which contributed to 50-60% of the influent SCOD. were removed by 90-95%, while less than 15% of the lignin-like material (30-35% of SCODin) was removed. The sludge yield was 0.23g VSSg SCOD(-1)removed. The results show that the aerobic biofilm process can be successfully operated under thermophilic conditions. PMID:11848344

  10. Diversity of aerobic methanotrophic bacteria in a permafrost active layer soil of the Lena Delta, Siberia.

    PubMed

    Liebner, Susanne; Rublack, Katja; Stuehrmann, Torben; Wagner, Dirk

    2009-01-01

    With this study, we present first data on the diversity of aerobic methanotrophic bacteria (MOB) in an Arctic permafrost active layer soil of the Lena Delta, Siberia. Applying denaturing gradient gel electrophoresis and cloning of 16S ribosomal ribonucleic acid (rRNA) and pmoA gene fragments of active layer samples, we found a general restriction of the methanotrophic diversity to sequences closely related to the genera Methylobacter and Methylosarcina, both type I MOB. In contrast, we revealed a distinct species-level diversity. Based on phylogenetic analysis of the 16S rRNA gene, two new clusters of MOB specific for the permafrost active layer soil of this study were found. In total, 8 out of 13 operational taxonomic units detected belong to these clusters. Members of these clusters were closely related to Methylobacter psychrophilus and Methylobacter tundripaludum, both isolated from Arctic environments. A dominance of MOB closely related to M. psychrophilus and M. tundripaludum was confirmed by an additional pmoA gene analysis. We used diversity indices such as the Shannon diversity index or the Chao1 richness estimator in order to compare the MOB community near the surface and near the permafrost table. We determined a similar diversity of the MOB community in both depths and suggest that it is not influenced by the extreme physical and geochemical gradients in the active layer. PMID:18592300

  11. Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; Gaspari, Daniel P; McQueen, Andrew D; Rodgers, John H; Castle, James W; Friesen, Vanessa; Haakensen, Monique

    2016-10-01

    Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios.

  12. Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

    PubMed

    Kinley, Ciera M; Gaspari, Daniel P; McQueen, Andrew D; Rodgers, John H; Castle, James W; Friesen, Vanessa; Haakensen, Monique

    2016-10-01

    Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios. PMID:27459161

  13. Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils.

    PubMed

    Royer, Laurel A; Lee, Linda S; Russell, Mark H; Nies, Loring F; Turco, Ronald F

    2015-06-01

    Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates.

  14. Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils.

    PubMed

    Royer, Laurel A; Lee, Linda S; Russell, Mark H; Nies, Loring F; Turco, Ronald F

    2015-06-01

    Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates. PMID:25449186

  15. Silicification-induced cell aggregation for the sustainable production of H2 under aerobic conditions.

    PubMed

    Xiong, Wei; Zhao, Xiaohong; Zhu, Genxing; Shao, Changyu; Li, Yaling; Ma, Weimin; Xu, Xurong; Tang, Ruikang

    2015-10-01

    Photobiological hydrogen production is of great importance because of its promise for generating clean renewable energy. In nature, green algae cannot produce hydrogen as a result of the extreme sensitivity of hydrogenase to oxygen. However, we find that silicification-induced green algae aggregates can achieve sustainable photobiological hydrogen production even under natural aerobic conditions. The core-shell structure of the green algae aggregates creates a balance between photosynthetic electron generation and hydrogenase activity, thus allowing the production of hydrogen. This finding provides a viable pathway for the solar-driven splitting of water into hydrogen and oxygen to develop green energy alternatives by using rationally designed cell-material complexes. PMID:26302695

  16. Mood after various brief exercise and sport modes: aerobics, hip-hop dancing, ice skating, and body conditioning.

    PubMed

    Kim, Sungwoon; Kim, Jingu

    2007-06-01

    To investigate the potential psychological benefits of brief exercise and sport activities on positive mood alterations, 45 Korean high school and 232 undergraduate students enrolled in physical education and stress management classes voluntarily participated and were randomly assigned to one of four activities: aerobic exercise, body conditioning, hip-hop dancing, and ice skating. Mood changes from before to after exercise (2 pm to 3 pm) were measured based on a Korean translation of the Subjective Exercise Experiences Scale. The findings suggested that the aerobics and hip-hop dancing groups rated positive well-being higher than the body conditioning and ice skating groups. Immediately after exercise, psychological distress was rated lower in the aerobics and hip-hop dancing groups, as was fatigue.

  17. Biodegradation of three- and four-ring polycyclic aromatic hydrocarbons under aerobic and denitrifying conditions

    SciTech Connect

    McNally, D.L.; Mihelcic, J.R.; Lueking, D.R.

    1998-09-01

    PAHs are thought to be particularly persistent in environments where anaerobic conditions exist. This study presents evidence for the biodegradation of three- and four-ringed PAHs (anthracene, phenanthrene, and pyrene) under strict anaerobic, denitrifying conditions. Three pseudomonad strains, isolated from contrasting environments, were used in this study. All three strains were known PAH degraders and denitrifiers. Degradation proceeded to nondetectable levels in 12--80 h for anthracene, 12--44 h for phenanthrene, and 24--72 h for pyrene. The rates of anaerobic degradation were typically slower than under aerobic conditions in almost all cases, except for strain SAG-R which had similar removal rates for all three and four-ring PAHs. Denitrification activity was verified by monitoring nitrate utilization and nitrous oxide production. Although none of the pseudomonads were adapted to the denitrifying conditions, only the pseudomonad isolated from a noncontaminated site consistently exhibited an adaptation period which approximated 12 h. This study supports growing evidence that the degradation of aromatic hydrocarbons coupled to denitrification may be an important factor affecting the fate of these compounds in natural and engineered systems.

  18. Decolorization of azo dyes under batch anaerobic and sequential anaerobic/aerobic conditions.

    PubMed

    Işik, Mustafa; Sponza, Delia Teresa

    2004-01-01

    Batch anaerobic and sequential anaerobic upflow anaerobic sludge blanket (UASB)/aerobic continuous stirred tank reactor (CSTR) were used to determine the color and COD removals under anaerobic/aerobic conditions. Two azo dyes namely "Reactive Black 5 (RB 5)," "Congo Red (CR)," and glucose as a carbon source were used for synthetic wastewater. The course of the decolorization process approximates to first order and zero order kinetics with respect to dye concentration for RB 5 and Congo Red azo dyes, respectively, in batch conditions. The decolorization kinetic constant (K0) values increased from 3.6 to 11.8 mg(L h)(-1) as increases in dye concentrations from 200 to 3200 mg L(-1) for CR. Increases in dye concentrations from 0 to 3200 mg L(-1) reduce the decolorization rate constant (k1) values from 0.0141 to 0.0019 h(-1) in batch studies performed with RB 5. Decolorization was achieved effectively under test conditions but ultimate decolorization of azo dyes was not observed at all dye concentrations in batch assay conditions. Dye concentrations of 100 mg L(-1) and 3000 mg L(-1) of glucose-COD containing basal medium were used for continuous studies. The effect of organic loadings and HRT, on the color removal efficiencies and methane gas productions were monitored. 94.1-45.4% COD and 79-73% color removal efficiencies were obtained at an organic system during decolorization of Reactive Black 5. 92.3-77.0% COD and 95.3-92.2% decolorization efficiencies were achieved at a organic loading rate of 1.03-6.65 kg (m3 day)(-1) and a HRT of 3.54-0.49 for Congo Red treatment. The results of this study showed that, although decolorization continued, COD removal efficiencies and methane gas production were depressed at high organic loadings under anaerobic conditions. Furthermore, VFA accumulation, alkalinity consumption, and methane gas percentage were monitored at organic loading as high as 2.49-4.74 kg (m3 day)(-1) and 24.60-30.62 kg (m3 day)(-1), respectively, through the

  19. On-farm treatment of dairy soiled water using aerobic woodchip filters.

    PubMed

    Ruane, Eimear M; Murphy, Paul N C; Healy, Mark G; French, Padraig; Rodgers, Michael

    2011-12-15

    Dairy soiled water (DSW) is produced on dairy farms through the washing-down of milking parlours and holding areas, and is generally applied to land. However, there is a risk of nutrient loss to surface and ground waters from land application. The aim of this study was to use aerobic woodchip filters to remove organic matter, suspended solids (SS) and nutrients from DSW. This novel treatment method would allow the re-use of the final effluent from the woodchip filters to wash down yards, thereby reducing water usage and environmental risks associated with land spreading. Three replicate 100 m(2) farm-scale woodchip filters, each 1 m deep, were constructed and operated to treat DSW from 300 cows over an 11-month study duration. The filters were loaded at a hydraulic loading rate of 30 L m(-2) d(-1), applied in four doses through a network of pipes on the filter surface. Average influent concentrations of chemical oxygen demand (COD), SS and total nitrogen (TN) of 5750 ± 1441 mg L(-1), 602 ± 303 mg L(-1) and 357 ± 100 mg L(-1), respectively, were reduced by 66, 86 and 57% in the filters. Effluent nutrient concentrations remained relatively stable over the study period, indicating the effectiveness of the filter despite increasing and/or fluctuating influent concentrations. Woodchip filters are a low cost, minimal maintenance treatment system, using a renewable resource that can be easily integrated into existing farm infrastructure.

  20. Can hydromorphic conditions accelerate soil development?

    NASA Astrophysics Data System (ADS)

    Ringer, Marianna; Kiss, Klaudia; Horváth-Szabó, Kata; Réka Balázs, Brigitta; Németh, Tibor; Sipos, Péter; Szabó, Máté; Jakab, Gergely; Madarász, Balázs; Szalai, Zoltán

    2016-04-01

    The formation and development of waterlogged (hydromorphic) soils are primarily determined by long-term water saturation. The presence of water in the profile can result increasing speed of soil forming processes including the accumulation of organic matter or other components and mineralogical transformations. Original papers refer more than hundreds of years for this kinds of mineral transformations. We suppose that this process could be more rapid. This study focuses on the mineralogical investigation of a sandy meadow soil (calcic, gleyic Phaeozem ferric, arenic) located in a swampy area in Central Hungary. The starting time of the soil formation is a well documented fact: the parent material deposited during an extremely heavy flood event in the 1960s. Therefore, the studied soil profile is the result of the last half century. Our aim was to explore the degree of mineral phase alteration via soil formation during a half-century under hydromorphic conditions. Routine laboratory measurements (selective dissolution methods for the determination of amorphous and crystalline Fe, and Mn content, X-ray fluorescence spectroscopy measurements for elemental composition determination, X-ray powder diffraction for mineralogical composition, and particle sizing by laser diffraction) were implemented. Morphological and chemical study of carbonate and iron nodules was carried out by electron microprobe. Simple chemical tests (eg. Fe2+ indication by dipiridil test) and morphological observations were performed on the field. Redox potential (Eh) and pH were measured in 20 cm and 40 cm depths by field monitoring station during the vegetation period. Results show that well developed horizons have emerged during fifty years in the studied soil profile. The most intense mineralogical transformations developed in the zone of the heaviest redox oscillation. Soil formation under hydromorphic conditions proceeds at higher speeds contrariwise to the century time scale reported in

  1. Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions.

    PubMed

    Menahem, Adi; Dror, Ishai; Berkowitz, Brian

    2016-02-01

    The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions.

  2. Intensification of the aerobic bioremediation of an actual site soil historically contaminated by polychlorinated biphenyls (PCBs) through bioaugmentation with a non acclimated, complex source of microorganisms

    PubMed Central

    Di Toro, Sara; Zanaroli, Giulio; Fava, Fabio

    2006-01-01

    Background The biotreatability of actual-site polychlorinated biphenyl (PCB)-contaminated soils is often limited by their poor content of autochthonous pollutant-degrading microorganisms. In such cases, inoculation might be the solution for a successful bioremediation. Some pure and mixed cultures of characterized PCB degrading bacteria have been tested to this purpose. However, several failures have been recorded mostly due to the inability of inoculated microbes to compete with autochthonous microflora and to face the toxicity and the scarcity of nutrients occurring in the contaminated biotope. Complex microbial systems, such as compost or sludge, normally consisting of a large variety of robust microorganisms and essential nutrients, would have better chances to succeed in colonizing degraded contaminated soils. However, such sources of microorganisms have been poorly applied in soil bioremediation and in particular in the biotreatment of soil with PCBs. Thus, in this study the effects of Enzyveba, i.e. a consortium of non-adapted microorganisms developed from composted material, on the slurry- and solid-phase aerobic bioremediation of an actual-site, aged PCB-contaminated soil were studied. Results A slow and only partial biodegradation of low-chlorinated biphenyls, along with a moderate depletion of initial soil ecotoxicity, were observed in the not-inoculated reactors. Enzyveba significantly increased the availability and the persistence of aerobic PCB- and chlorobenzoic acid-degrading cultivable bacteria in the bioreactors, in particular during the earlier phase of treatment. It also markedly enhanced PCB-biodegradation rate and extent (from 50 to 100%) as well as the final soil detoxification, in particular under slurry-phase conditions. Taken together, data obtained suggest that Enzyveba enhanced the biotreatability of the selected soil by providing exogenous bacteria and fungi able to remove inhibitory or toxic intermediates of PCB biodegradation and

  3. Effect of particulate organic substrate on aerobic granulation and operating conditions of sequencing batch reactors.

    PubMed

    Wagner, Jamile; Weissbrodt, David Gregory; Manguin, Vincent; da Costa, Rejane Helena Ribeiro; Morgenroth, Eberhard; Derlon, Nicolas

    2015-11-15

    The formation and application of aerobic granules for the treatment of real wastewaters still remains challenging. The high fraction of particulate organic matter (XS) present in real wastewaters can affect the granulation process. The present study aims at understanding to what extent the presence of XS affects the granule formation and the quality of the treated effluent. A second objective was to evaluate how the operating conditions of an aerobic granular sludge (AGS) reactor must be adapted to overcome the effects of the presence of XS. Two reactors fed with synthetic wastewaters were operated in absence (R1) or presence (R2) of starch as proxy for XS. Different operating conditions were evaluated. Our results indicated that the presence of XS in the wastewater reduces the kinetic of granule formation. After 52 d of operation, the fraction of granules reached only 21% in R2, while in R1 this fraction was of 54%. The granules grown in presence of XS had irregular and filamentous outgrowths in the surface, which affected the settleability of the biomass and therefore the quality of the effluent. An extension of the anaerobic phase in R2 led to the formation of more compact granules with a better settling ability. A high fraction of granules was obtained in both reactors after an increase of the selection pressure for fast-settling biomass, but the quality of the effluent remained low. Operating the reactors in a simultaneous fill-and-draw mode at a low selection pressure for fast-settling biomass showed to be beneficial for substrate removal efficiency and for suppressing filamentous overgrowth. Average removal efficiencies for total COD, soluble COD, ammonium, and phosphate were 87 ± 4%, 95 ± 1%, 92 ± 10%, and 87 ± 12% for R1, and 72 ± 12%, 86 ± 5%, 71 ± 12%, and 77 ± 11% for R2, respectively. Overall our study demonstrates that the operating conditions of AGS reactors must be adapted according to the wastewater composition. When treating effluents that

  4. Cr(VI) reduction under aerobic and denitrifying conditions by an aquifer-derived Pseudomonad

    NASA Astrophysics Data System (ADS)

    Beller, H. R.; Han, R.; Geller, J. T.

    2009-12-01

    Chromium contamination of groundwater is widespread within the Department of Energy (DOE) complex. For example, at DOE’s Hanford 100 Area in Washington state, the volume of Cr-contaminated groundwater is estimated to be 1.5 billion gallons. Bioremediation (in situ reductive immobilization) studies involving injection of a lactate-containing polymer have been conducted in the Hanford 100H area, where we have observed sequential use of the dissolved electron acceptors present in groundwater, namely, oxygen, nitrate, and sulfate. As part of an effort to explore Cr(VI) reduction under relevant electron-accepting conditions and with relevant bacteria, we have conducted studies with strain RCH2, a denitrifying bacterium similar to Pseudomonas stutzeri that was isolated from the Hanford 100H aquifer. Cell suspension studies with lactate demonstrated that Cr(VI) reduction could occur under either denitrifying or aerobic conditions (at comparable rates), and that reduction was much more rapid when the terminal electron acceptor (i.e., nitrate or O2) was present. It appears that, under both aerobic and denitrifying conditions, the chromate reductase gene(s) are not inducible by Cr; this conclusion is based on the fact that these cell suspension studies were conducted with cells grown in the absence of Cr and resuspended in a buffer that included chloramphenicol, which inhibits protein synthesis. As our studies indicate that anaerobic Cr(VI) reduction by strain RCH2 is much more rapid in the presence of nitrate (i.e., during denitrification) than in its absence, we explored molecular methods that could readily assess in situ denitrification. Specifically, we investigated whether the gene and transcript copy number of diagnostic denitrification genes (nirS and narG) in groundwater could be used to estimate in situ denitrification rates. Continuous culture (chemostat) studies showed strong correlations (r2 values > 0.93) between denitrification rate and either nirS or nar

  5. Plutonium Oxidation State Distribution under Aerobic and Anaerobic Subsurface Conditions for Metal-Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Reed, D. T.; Swanson, J.; Khaing, H.; Deo, R.; Rittmann, B.

    2009-12-01

    The fate and potential mobility of plutonium in the subsurface is receiving increased attention as the DOE looks to cleanup the many legacy nuclear waste sites and associated subsurface contamination. Plutonium is the near-surface contaminant of concern at several DOE sites and continues to be the contaminant of concern for the permanent disposal of nuclear waste. The mobility of plutonium is highly dependent on its redox distribution at its contamination source and along its potential migration pathways. This redox distribution is often controlled, especially in the near-surface where organic/inorganic contaminants often coexist, by the direct and indirect effects of microbial activity. The redox distribution of plutonium in the presence of facultative metal reducing bacteria (specifically Shewanella and Geobacter species) was established in a concurrent experimental and modeling study under aerobic and anaerobic conditions. Pu(VI), although relatively soluble under oxidizing conditions at near-neutral pH, does not persist under a wide range of the oxic and anoxic conditions investigated in microbiologically active systems. Pu(V) complexes, which exhibit high chemical toxicity towards microorganisms, are relatively stable under oxic conditions but are reduced by metal reducing bacteria under anaerobic conditions. These facultative metal-reducing bacteria led to the rapid reduction of higher valent plutonium to form Pu(III/IV) species depending on nature of the starting plutonium species and chelating agents present in solution. Redox cycling of these lower oxidation states is likely a critical step in the formation of pseudo colloids that may lead to long-range subsurface transport. The CCBATCH biogeochemical model is used to explain the redox mechanisms and final speciation of the plutonium oxidation state distributions observed. These results for microbiologically active systems are interpreted in the context of their importance in defining the overall migration

  6. Complete remediation of PCE contaminated unsaturated soils by sequential anaerobic-aerobic bioventing.

    PubMed

    Mihopoulos, P G; Suidan, M T; Sayles, G D

    2001-01-01

    Bioventing principles have been applied to completely dechlorinate tetrachloroethylene vapors in the unsaturated zone in a sequential anaerobic-aerobic pattern. The aerobic step yields trans-DCE and VC as PCE reductive dechlorination byproducts, while TCE and cis-DCE are observed as intermediates. The aerobic step results in rapid oxidation of the VC and trans-DCE to carbon dioxide. Hydrogen was delivered in the gas phase as a reducing agent for the anaerobic step at levels of 1%, and oxygen at 4.2% was used as an electron acceptor in the aerobic step. PCE and VC half lives in the anaerobic and aerobic steps respectively, where less than 10 min.

  7. Quantitative proteome and transcriptome analysis of the archaeon Thermoplasma acidophilum cultured under aerobic and anaerobic conditions.

    PubMed

    Sun, Na; Pan, Cuiping; Nickell, Stephan; Mann, Matthias; Baumeister, Wolfgang; Nagy, István

    2010-09-01

    A comparative proteome and transcriptome analysis of Thermoplasma acidophilum cultured under aerobic and anaerobic conditions has been performed. One-thousand twenty-five proteins were identified covering 88% of the cytosolic proteome. Using a label-free quantitation method, we found that approximately one-quarter of the identified proteome (263 proteins) were significantly induced (>2 fold) under anaerobic conditions. Thirty-nine macromolecular complexes were identified, of which 28 were quantified and 15 were regulated under anaerobiosis. In parallel, a whole genome cDNA microarray analysis was performed showing that the expression levels of 445 genes were influenced by the absence of oxygen. Interestingly, more than 40% of the membrane protein-encoding genes (145 out of 335 ORFs) were up- or down-regulated at the mRNA level. Many of these proteins are functionally associated with extracellular protein or peptide degradation or ion and amino acid transport. Comparison of the transcriptome and proteome showed only a weak positive correlation between mRNA and protein expression changes, which is indicative of extensive post-transcriptional regulatory mechanisms in T. acidophilum. Integration of transcriptomics and proteomics data generated hypotheses for physiological adaptations of the cells to anaerobiosis, and the quantitative proteomics data together with quantitative analysis of protein complexes provide a platform for correlation of MS-based proteomics studies with cryo-electron tomography-based visual proteomics approaches.

  8. Monitoring of growth and physiological activities of biofilm during succession on polystyrene from activated sludge under aerobic and anaerobic conditions.

    PubMed

    Naz, Iffat; Batool, Syeda Ain-ul; Ali, Naeem; Khatoon, Nazia; Atiq, Niama; Hameed, Abdul; Ahmed, Safia

    2013-08-01

    The present research work monitored the successive biofilm development and its catabolic role in the degradation of polystyrene (PS). PS material was artificially colonized with biofilm by incubating it with activated sludge under aerobic and anaerobic conditions. Biofilm formation was monitored by gravimetric weight analysis, spectrophotometric absorbance technique, heterotrophic plate count, and scanning electron microscopy under aerobic and anaerobic conditions. The wet weight (1.59 and 1.17 g) and dry weight (0.41 and 0.08 g) of a biofilm showed a significant constant increase under aerobic and anaerobic conditions, respectively, from first till 9 weeks of incubation. Plate count of the selected bacteria (Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Pseudomonas aeruginosa) considerably declined (90-99 %) in the biofilm after seventh and fifth weeks of incubation under aerobic and anaerobic conditions, respectively, indicating a positive shift from pathogenic to beneficial microbial community. While most probable number index of fecal coliforms and E. coli in the sludge showed more reduction (98 and 99 %) under aerobic as compare to anaerobic conditions (86 and 91 %) after 9 weeks of biofilm formation on PS cubes. Correspondingly, the decreasing levels of chemical oxygen demand and biochemical oxygen demand (up to 73 %) showed signs of sludge digestion. Scanning electron microscope coupled with energy dispersive X-ray spectroscope revealed nature of PS media containing high carbon content. However, biofilm development proved to be involved in the biochemical transformation of the PS medium as indicated by Fourier transform infrared spectroscopy.

  9. Impact of ArcA loss in Shewanella oneidensis revealed by comparative proteomics under aerobic and anaerobic conditions

    SciTech Connect

    Yuan, Jie; Wei, Buyun; Lipton, Mary S.; Gao, Haichun

    2012-06-01

    Shewanella inhabit a wide variety of niches in nature and can utilize a broad spectrum of electron acceptors under anaerobic conditions. How they modulate their gene expression to adapt is poorly understood. ArcA, homologue of a global regulator controlling hundreds of genes involved in aerobic and anaerobic respiration in E. coli, was shown to be important in aerobiosis/anaerobiosis of S. oneidensis as well. Loss of ArcA, in addition to altering transcription of many genes, resulted in impaired growth under aerobic condition, which was not observed in E. coli. To further characterize the impact of ArcA loss on gene expression on the level of proteome under aerobic and anaerobic conditions, liquid-chromatography-mass-spectrometry (LC-MS) based proteomic approach was employed. Results show that ArcA loss led to globally altered gene expression, generally consistent with that observed with transcripts. Comparison of transcriptomic and proteomic data permitted identification of 17 high-confidence ArcA targets. Moreover, our data indicate that ArcA is required for regulation of cytochrome c proteins, and the menaquinone level may play a role in regulating ArcA as in E. coli. Proteomic-data-guided growth assay revealed that the aerobic growth defect of ArcA mutant is presumably due to impaired peptide utilization.

  10. Electrolysis of trichloromethylated organic compounds under aerobic conditions catalyzed by the B12 model complex for ester and amide formation.

    PubMed

    Shimakoshi, Hisashi; Luo, Zhongli; Inaba, Takuya; Hisaeda, Yoshio

    2016-06-21

    The electrolysis of benzotrichloride at -0.9 V vs. Ag/AgCl in the presence of the B12 model complex, heptamethyl cobyrinate perchlorate, in ethanol under aerobic conditions using an undivided cell equipped with a platinum mesh cathode and a zinc plate anode produced ethylbenzoate in 56% yield with 92% selectivity. The corresponding esters were obtained when the electrolysis was carried out in various alcohols such as methanol, n-propanol, and i-propanol. Benzoyl chloride was detected by GC-MS during the electrolysis as an intermediate for the ester formation. When the electrolysis was carried out under anaerobic conditions, partially dechlorinated products, 1,1,2,2-tetrachloro-1,2-diphenylethane and 1,2-dichlorostilibenes (E and Z forms), were obtained instead of an ester. ESR spin-trapping experiments using 5,5,-dimethylpyrroline N-oxide (DMPO) revealed that the corresponding oxygen-centered radical and carbon-centered radical were steadily generated during the electrolyses under aerobic and anaerobic conditions, respectively. Applications of the aerobic electrolysis to various organic halides, such as substituted benzotrichlorides, are described. Furthermore, the formation of amides with moderate yields by the aerobic electrolysis of benzotrichloride catalyzed by the B12 model complex in the presence of amines in acetonitrile is reported. PMID:27071703

  11. Efficient production and secretion of pyruvate from Halomonas sp. KM-1 under aerobic conditions.

    PubMed

    Kawata, Yoshikazu; Nishimura, Taku; Matsushita, Isao; Tsubota, Jun

    2016-03-01

    The alkaliphilic, halophilic bacterium Halomonas sp. KM-1 can utilize both hexose and pentose sugars for the intracellular storage of bioplastic poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. In this study, we investigated the effects of the sodium nitrate concentration on PHB accumulation in the KM-1 strain. Unexpectedly, we observed the secretion of pyruvate, a central intermediate in carbon- and energy-metabolism processes in all organisms; therefore, pyruvate is widely used as a starting material in the industrial biosynthesis of pharmaceuticals and is employed for the production of crop-protection agents, polymers, cosmetics, and food additives. We then further analyzed pyruvate productivity following changes in culture temperature and the buffer concentration. In 48-h batch-cultivation experiments, we found that wild-type Halomonas sp. KM-1 secreted 63.3 g/L pyruvate at a rate of 1.32 g/(L·h), comparable to the results of former studies using mutant and recombinant microorganisms. Thus, these data provided important insights into the production of pyruvate using this novel strain.

  12. Optimization of polyhydroxybutyrate production by mixed cultures submitted to aerobic dynamic feeding conditions.

    PubMed

    Serafim, Luísa S; Lemos, Paulo C; Oliveira, Rui; Reis, Maria A M

    2004-07-20

    Activated sludge submitted to aerobic dynamic feeding conditions showed a good and stable capacity to store polyhydroxybutyrate (PHB). The system, working for 2 years, selected a microbial population with a high PHB storage capacity. The influence of carbon and nitrogen concentrations on the PHB accumulation yield was studied in a range of 15-180 Cmmol/l for acetate and 0-2.8 Nmmol/l for ammonia. Low ammonia concentrations favored PHB accumulation. The maximum PHB content, 67.5%, was obtained for 180 Cmmol/l of acetate supplied in one pulse. However, such high substrate concentration proved to be inhibitory for the storage mechanism, causing a slowdown of the specific PHB storage rate. In order to avoid substrate inhibition, 180 Cmmol/l of acetate was supplied in different ways: continuously fed and in three pulses of 60 Cmmol/l each. In both cases the specific PHB storage rate increased and the PHB content obtained were 56.2% and 78.5%, respectively. The latter value of PHB content is similar to that obtained by pure cultures and was never reported for mixed cultures. Addition of acetate by pulses controlled by the oxygen concentration was kept for 16 days, the PHB content being always above 70% of cell dry weight.

  13. Oxidation of aquatic pollutants by ferrous-oxalate complexes under dark aerobic conditions.

    PubMed

    Lee, Jaesang; Kim, Jungwon; Choi, Wonyong

    2014-06-15

    This study evaluates the ability of Fe(II)-oxalate complexes for the generation of OH through oxygen reduction and the oxidative degradation of aquatic pollutants under dark aerobic conditions (i.e., with oxygen but without light). The degradation of 4-chlorophenol (4-CP) was rapid in the mixture of Fe(2+) and oxalate prepared using ultrapure water, but was absent without either Fe(2+) or oxalate. The formation of Fe(II)-oxalate complexes enables two-electron reduction of oxygen to generate H2O2 and subsequent production of OH. The significant inhibition of 4-CP degradation in the presence of H2O2 and OH scavenger confirms such mechanisms. The degradation experiments with varying [Fe(2+)], [oxalate], and initial pH demonstrated that the degradation rate depends on [Fe(II)(Ox)2(2-)], but the degree of degradation is primarily determined by [Fe(II)(Ox)2(2-)]+[Fe(II)(Ox)(0)]. Efficient degradation of diverse aquatic pollutants, especially phenolic pollutants, was observed in the Fe(II)-oxalate complexes system, wherein the oxidation efficacy was primarily correlated with the reaction rate constant between pollutant and OH. The effect of various organic ligands (oxalate, citrate, EDTA, malonate, and acetate) on the degradation kinetics of 4-CP was investigated. The highest efficiency of oxalate for the oxidative degradation is attributed to its high capability to enhance the reducing power and low reactivity with OH.

  14. Understanding the physiological roles of polyhydroxybutyrate (PHB) in Rhodospirillum rubrum S1 under aerobic chemoheterotrophic conditions.

    PubMed

    Narancic, Tanja; Scollica, Elisa; Kenny, Shane T; Gibbons, Helena; Carr, Eibhlin; Brennan, Lorraine; Cagney, Gerard; Wynne, Kieran; Murphy, Cormac; Raberg, Matthias; Heinrich, Daniel; Steinbüchel, Alexander; O'Connor, Kevin E

    2016-10-01

    Polyhydroxybutyrate (PHB) is an important biopolymer accumulated by bacteria and associated with cell survival and stress response. Here, we make two surprising findings in the PHB-accumulating species Rhodospirillum rubrum S1. We first show that the presence of PHB promotes the increased assimilation of acetate preferentially into biomass rather than PHB. When R. rubrum is supplied with (13)C-acetate as a PHB precursor, 83.5 % of the carbon in PHB comes from acetate. However, only 15 % of the acetate ends up in PHB with the remainder assimilated as bacterial biomass. The PHB-negative mutant of R. rubrum assimilates 2-fold less acetate into biomass compared to the wild-type strain. Acetate assimilation proceeds via the ethylmalonyl-CoA pathway with (R)-3-hydroxybutyrate as a common intermediate with the PHB pathway. Secondly, we show that R. rubrum cells accumulating PHB have reduced ribulose 1,5-bisphosphate carboxylase (RuBisCO) activity. RuBisCO activity reduces 5-fold over a 36-h period after the onset of PHB. In contrast, a PHB-negative mutant maintains the same level of RuBisCO activity over the growth period. Since RuBisCO controls the redox potential in R. rubrum, PHB likely replaces RuBisCO in this role. R. rubrum is the first bacterium found to express RuBisCO under aerobic chemoheterotrophic conditions. PMID:27480532

  15. Efficient production and secretion of pyruvate from Halomonas sp. KM-1 under aerobic conditions.

    PubMed

    Kawata, Yoshikazu; Nishimura, Taku; Matsushita, Isao; Tsubota, Jun

    2016-03-01

    The alkaliphilic, halophilic bacterium Halomonas sp. KM-1 can utilize both hexose and pentose sugars for the intracellular storage of bioplastic poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. In this study, we investigated the effects of the sodium nitrate concentration on PHB accumulation in the KM-1 strain. Unexpectedly, we observed the secretion of pyruvate, a central intermediate in carbon- and energy-metabolism processes in all organisms; therefore, pyruvate is widely used as a starting material in the industrial biosynthesis of pharmaceuticals and is employed for the production of crop-protection agents, polymers, cosmetics, and food additives. We then further analyzed pyruvate productivity following changes in culture temperature and the buffer concentration. In 48-h batch-cultivation experiments, we found that wild-type Halomonas sp. KM-1 secreted 63.3 g/L pyruvate at a rate of 1.32 g/(L·h), comparable to the results of former studies using mutant and recombinant microorganisms. Thus, these data provided important insights into the production of pyruvate using this novel strain. PMID:26989057

  16. Comparative studies on heavy metal uptake by plants from anaerobically and aerobically digested sludge-amended soil

    SciTech Connect

    Joseph, K.T.

    1983-01-01

    A study was undertaken to compare and contrast the effects of cropland application of varying quantities of anaerobically and aerobically digested sludge from a municipal wastewater treatment plant, on the uptake of certain heavy metals such as Zn, Cd, Cu, Ni, and Pb by six different types of plants (bean, tomato, carrot, cucumber, cantaloupe and sweet corn) grown on the sludge-applied soil and the accumulation of these metals in the sludge-amended soil. The main aspects of the study were the evaluation of 1) the extent of bioconcentration of heavy metals by the different kinds of plants, and 2) the availability of the metals from soil to plants, following sludge application. Field investigations involving plot-scale gardening were conducted using the two types of sludge, at application rates of 0, 2.2, 4.4, 8.8, 17.6 and 70.4 tons/acre. At application rates of 17.6 and 70.4 tons/acre, delays in germination of seeds were observed in some instances, with no apparent adverse effects on the plant's later stages of life and the yield produced. The uptake of heavy metals from sludge-amended soil by plants did not increase in direct proportion to the increase in rate of sludge application and plant species differ considerably in their uptake of heavy metals from soil which received the same amount of sludge. In general, plants grown on anaerobically digested sludge-applied soil showed higher uptake of heavy metals than those grown on aerobically digested sludge. Among the plants investigated, sweet corn was identified to be the low accumulator of heavy metals in the edible part of the plant.

  17. Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

    PubMed

    Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

    2015-06-01

    Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly. PMID:25845997

  18. Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

    PubMed

    Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

    2015-06-01

    Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly.

  19. Bacterial survival and association with sludge flocs during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions.

    PubMed Central

    Farrah, S R; Bitton, G

    1983-01-01

    The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the percentage of bacteria in the supernatant. The major factor influencing survival of Salmonella typhimurium and indicator bacteria during aerobic digestion was the temperature of sludge digestion. At 28 degrees C with greater than 4 mg of dissolved oxygen per liter, the daily change in numbers of these bacteria was approximately -1.0 log10/ml. At 6 degrees C, the daily change was less than -0.3 log10/ml. Most of the bacteria were associated with the sludge flocs during aerobic digestion of sludge at 28 degrees C with greater than 2.4 mg of dissolved oxygen per liter. Lowering the temperature or the amount of dissolved oxygen decreased the fraction of bacteria associated with the flocs and increased the fraction found in the supernatant. PMID:6401978

  20. Modeling the influence of varying hydraulic conditions on aerobic respiration and denitrification in the hyporheic zone

    NASA Astrophysics Data System (ADS)

    Trauth, N.; Schmidt, C.; Fleckenstein, J. H.

    2013-12-01

    Exchange of water and solutes across the stream-sediment interface is an important control for biogeochemical transformations in the hyporheic zone (HZ) with measurable impacts on nutrient cycling and solute attenuation in fluvial systems. Here we investigate the interplay between turbulent stream flow and HZ flow under various hydraulic conditions applied to two cases: a) three-dimensional generic pool-riffle sequences with different morphological properties, and b) a real mid-stream gravel-bar. Stream flow is simulated by the open source computational fluid dynamics (CFD) software OpenFOAM which provides the hydraulic head distribution at the streambed. It is sequentially coupled to the top of the groundwater model code MIN3P, simulating flow, solute transport, aerobic respiration (AR) and denitrification (DN) in the HZ. Flow in the HZ is directly influenced by the hydraulic head distribution at the streambed surface and the ambient groundwater flow. Three reactive transport scenarios are considered: 1) stream water as the primary source of dissolved oxygen (DO), nitrate (NO3) and dissolved organic carbon (DOC), 2) upwelling groundwater as an additionally source of NO3, and 3) upwelling groundwater as an additional source of DO in various concentrations. Results show an increase in hyporheic exchange flow for increasing stream discharge with a concurrent decrease in residence time. The fraction of circulating stream water through the HZ is in the range of 1x10-5 to 1x10-6 per unit stream length, decreasing with increasing discharge. Ambient groundwater flow in both the up- and downwelling direction diminishes significantly the hyporheic exchange flow and extent. Biogeochemical processes in the HZ are strongly controlled by ambient groundwater flow, even more so than by changes in stream discharge. AR and DN efficiencies of the HZ are significantly reduced by up- and downwelling groundwater and are positively correlated with median residence times. AR occurs in

  1. Physiological activities associated with biofilm growth in attached and suspended growth bioreactors under aerobic and anaerobic conditions.

    PubMed

    Naz, Iffat; Seher, Shama; Perveen, Irum; Saroj, Devendra P; Ahmed, Safia

    2015-01-01

    This research work evaluated the biofilm succession on stone media and compared the biochemical changes of sludge in attached and suspended biological reactors operated under aerobic and anaerobic conditions. Stones incubated (30±2°C) with activated sludge showed a constant increase in biofilm weight up to the fifth and seventh week time under anaerobic and aerobic conditions, respectively, where after reduction (>80%) the most probable number index of pathogen indicators on ninth week was recorded. Reduction in parameters such as biological oxygen demand (BOD) (47.7%), chemical oxygen demand (COD, 41%), nitrites (60.2%), nitrates (105.5%) and phosphates (58.9%) and increase in dissolved oxygen (176.5%) of sludge were higher in aerobic attached growth reactors as compared with other settings. While, considerable reductions in these values were also observed (BOD, 53.8%; COD, 2.8%; nitrites, 28.6%; nitrates, 31.7%; phosphates, 41.4%) in the suspended growth system under anaerobic conditions. However, higher sulphate removal was observed in suspended (40.9% and 54.9%) as compared with biofilm reactors (28.2% and 29.3%). Six weeks biofilm on the stone media showed maximum physiological activities; thus, the operational conditions should be controlled to keep the biofilm structure similar to six-week-old biofilm, and can be used in fixed biofilm reactors for wastewater treatment.

  2. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions

    NASA Astrophysics Data System (ADS)

    Lahvis, Matthew A.; Baehr, Arthur L.; Baker, Ronald J.

    1999-03-01

    Aerobic biodegradation and volatilization near the water table constitute a coupled pathway that contributes significantly to the natural attenuation of hydrocarbons at gasoline spill sites. Rates of hydrocarbon biodegradation and volatilization were quantified by analyzing vapor transport in the unsaturated zone at a gasoline spill site in Beaufort, South Carolina. Aerobic biodgradation rates decreased with distance above the water table, ranging from 0.20 to 1.5 g m-3 d-1 for toluene, from 0.24 to 0.38 g m-3 d-1 for xylene, from 0.09 to 0.24 g m-3 d-1 for cyclohexene, from 0.05 to 0.22 g m-3 d-1 for ethylbenzene, and from 0.02 to 0.08 g m-3 d-1 for benzene. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Hydrocarbons were nearly completely degraded within 1m above the water table. This large loss underscores the importance of aerobic biodradation in limiting the transport of hydrocarbon vapors in the unsaturated zone and implies that vapor-plume migration to basements and other points of contact may only be significant if a source of free product is present. Furthermore, because transport of the hydrocarbon in the unsaturated zone can be limited relative to that of oxygen and carbon dioxide, soil-gas surveys conducted at hydrocarbon-spill sites would benefit by the inclusion of oxygen- and carbon-dioxide-gas concentration measurements. Aerobic degradation kinetics in the unsaturated zone were approximately first-order. First-order rate constants near the water table were highest for cyclohexene (0.21-0.65 d-1) and nearly equivalent for ethylbenzene (0.11-0.31 d-1), xylenes (0.10-0.31 d-1), toluene (0.09-0.30 d-1), and benzene (0.07-0.31 d-1). Hydrocarbon mass loss rates at the water table resulting from the coupled aerobic biodgradation and volatilization process were determined by extrapolating gas transport rates through the capillary zone. Mass loss

  3. The bifunctional aldehyde-alcohol dehydrogenase controls ethanol and acetate production in Entamoeba histolytica under aerobic conditions.

    PubMed

    Pineda, Erika; Encalada, Rusely; Olivos-García, Alfonso; Néquiz, Mario; Moreno-Sánchez, Rafael; Saavedra, Emma

    2013-01-16

    By applying metabolic control analysis and inhibitor titration we determined the degree of control (flux control coefficient) of pyruvate:ferredoxin oxidoreductase (PFOR) and bifunctional aldehyde-alcohol dehydrogenase (ADHE) over the fluxes of fermentative glycolysis of Entamoeba histolytica subjected to aerobic conditions. The flux-control coefficients towards ethanol and acetate formation determined for PFOR titrated with diphenyleneiodonium were 0.07 and 0.09, whereas for ADHE titrated with disulfiram were 0.33 and -0.19, respectively. ADHE inhibition induced significant accumulation of glycolytic intermediates and lower ATP content. These results indicate that ADHE exerts significant flux-control on the carbon end-product formation of amoebas subjected to aerobic conditions. PMID:23201265

  4. Chromium isotopic fractionation during Cr(VI) reduction by Bacillus sp. under aerobic conditions.

    PubMed

    Xu, Fen; Ma, Teng; Zhou, Lian; Hu, Zhifang; Shi, Liu

    2015-07-01

    This study investigated the fractionation of chromium isotopes during chromium reduction by Bacillus sp. under aerobic condition, variable carbon source (glucose) concentration (0, 0.1, 1, 2.5 and 10mM), and incubation temperatures (4, 15, 25 and 37°C). The results revealed that the δ(53)Cr values in the residual Cr(VI) increased with the degree of Cr reduction, and followed a Rayleigh fractionation model. The addition of glucose only slightly affected cell-specific Cr(VI) reduction rates (cSRR). However, the value of ε (2.00±0.21‰) in the experiments with different concentrations of glucose (0.1, 1, 2.5 and 10mM) was smaller than that from the experiment without glucose (3.74±0.16‰). The results indicated that the cell-specific reduction rate is not the sole control on the degree of isotopic fractionation, and different metabolic pathways would result in differing degrees of Cr isotopic fractionation. The cSRR decreased with decreasing temperature, showing that the values of ε were 7.62±0.36‰, 4.59±0.28‰, 3.09±0.16‰ and 1.99±0.23‰ at temperatures of 4, 15, 25 and 37°C, respectively. It shown that increasing cSRR linked to decreasing fractionations has been associated with increasing temperatures. Overall, our results revealed that temperature is a primary factor affecting Cr isotopic fractionation under microbial actions.

  5. A Model of the Cardiorespiratory Response to Aerobic Exercise in Healthy and Heart Failure Conditions.

    PubMed

    Fresiello, Libera; Meyns, Bart; Di Molfetta, Arianna; Ferrari, Gianfranco

    2016-01-01

    The physiological response to physical exercise is now recognized as an important tool which can aid the diagnosis and treatment of cardiovascular diseases. This is due to the fact that several mechanisms are needed to accommodate a higher cardiac output and a higher oxygen delivery to tissues. The aim of the present work is to provide a fully closed loop cardiorespiratory simulator reproducing the main physiological mechanisms which arise during aerobic exercise. The simulator also provides a representation of the impairments of these mechanisms in heart failure condition and their effect on limiting exercise capacity. The simulator consists of a cardiovascular model including the left and right heart, pulmonary and systemic circulations. This latter is split into exercising and non-exercising regions and is controlled by the baroreflex and metabolic mechanisms. In addition, the simulator includes a respiratory model reproducing the gas exchange in lungs and tissues, the ventilation control and the effects of its mechanics on the cardiovascular system. The simulator was tested and compared to the data in the literature at three different workloads whilst cycling (25, 49 and 73 watts). The results show that the simulator is able to reproduce the response to exercise in terms of: heart rate (from 67 to 134 bpm), cardiac output (from 5.3 to 10.2 l/min), leg blood flow (from 0.7 to 3.0 l/min), peripheral resistance (from 0.9 to 0.5 mmHg/(cm(3)/s)), central arteriovenous oxygen difference (from 4.5 to 10.8 ml/dl) and ventilation (6.1-25.5 l/min). The simulator was further adapted to reproduce the main impairments observed in heart failure condition, such as reduced sensitivity of baroreflex and metabolic controls, lower perfusion to the exercising regions (from 0.6 to 1.4 l/min) and hyperventilation (from 9.2 to 40.2 l/min). The simulator we developed is a useful tool for the description of the basic physiological mechanisms operating during exercise. It can reproduce

  6. A Model of the Cardiorespiratory Response to Aerobic Exercise in Healthy and Heart Failure Conditions

    PubMed Central

    Fresiello, Libera; Meyns, Bart; Di Molfetta, Arianna; Ferrari, Gianfranco

    2016-01-01

    The physiological response to physical exercise is now recognized as an important tool which can aid the diagnosis and treatment of cardiovascular diseases. This is due to the fact that several mechanisms are needed to accommodate a higher cardiac output and a higher oxygen delivery to tissues. The aim of the present work is to provide a fully closed loop cardiorespiratory simulator reproducing the main physiological mechanisms which arise during aerobic exercise. The simulator also provides a representation of the impairments of these mechanisms in heart failure condition and their effect on limiting exercise capacity. The simulator consists of a cardiovascular model including the left and right heart, pulmonary and systemic circulations. This latter is split into exercising and non-exercising regions and is controlled by the baroreflex and metabolic mechanisms. In addition, the simulator includes a respiratory model reproducing the gas exchange in lungs and tissues, the ventilation control and the effects of its mechanics on the cardiovascular system. The simulator was tested and compared to the data in the literature at three different workloads whilst cycling (25, 49 and 73 watts). The results show that the simulator is able to reproduce the response to exercise in terms of: heart rate (from 67 to 134 bpm), cardiac output (from 5.3 to 10.2 l/min), leg blood flow (from 0.7 to 3.0 l/min), peripheral resistance (from 0.9 to 0.5 mmHg/(cm3/s)), central arteriovenous oxygen difference (from 4.5 to 10.8 ml/dl) and ventilation (6.1–25.5 l/min). The simulator was further adapted to reproduce the main impairments observed in heart failure condition, such as reduced sensitivity of baroreflex and metabolic controls, lower perfusion to the exercising regions (from 0.6 to 1.4 l/min) and hyperventilation (from 9.2 to 40.2 l/min). The simulator we developed is a useful tool for the description of the basic physiological mechanisms operating during exercise. It can reproduce

  7. A Model of the Cardiorespiratory Response to Aerobic Exercise in Healthy and Heart Failure Conditions.

    PubMed

    Fresiello, Libera; Meyns, Bart; Di Molfetta, Arianna; Ferrari, Gianfranco

    2016-01-01

    The physiological response to physical exercise is now recognized as an important tool which can aid the diagnosis and treatment of cardiovascular diseases. This is due to the fact that several mechanisms are needed to accommodate a higher cardiac output and a higher oxygen delivery to tissues. The aim of the present work is to provide a fully closed loop cardiorespiratory simulator reproducing the main physiological mechanisms which arise during aerobic exercise. The simulator also provides a representation of the impairments of these mechanisms in heart failure condition and their effect on limiting exercise capacity. The simulator consists of a cardiovascular model including the left and right heart, pulmonary and systemic circulations. This latter is split into exercising and non-exercising regions and is controlled by the baroreflex and metabolic mechanisms. In addition, the simulator includes a respiratory model reproducing the gas exchange in lungs and tissues, the ventilation control and the effects of its mechanics on the cardiovascular system. The simulator was tested and compared to the data in the literature at three different workloads whilst cycling (25, 49 and 73 watts). The results show that the simulator is able to reproduce the response to exercise in terms of: heart rate (from 67 to 134 bpm), cardiac output (from 5.3 to 10.2 l/min), leg blood flow (from 0.7 to 3.0 l/min), peripheral resistance (from 0.9 to 0.5 mmHg/(cm(3)/s)), central arteriovenous oxygen difference (from 4.5 to 10.8 ml/dl) and ventilation (6.1-25.5 l/min). The simulator was further adapted to reproduce the main impairments observed in heart failure condition, such as reduced sensitivity of baroreflex and metabolic controls, lower perfusion to the exercising regions (from 0.6 to 1.4 l/min) and hyperventilation (from 9.2 to 40.2 l/min). The simulator we developed is a useful tool for the description of the basic physiological mechanisms operating during exercise. It can reproduce

  8. A study of the thermal decomposition of adulterated cocaine samples under optimized aerobic pyrolytic conditions.

    PubMed

    Gostic, T; Klemenc, S; Stefane, B

    2009-05-30

    The pyrolysis behaviour of pure cocaine base as well as the influence of various additives was studied using conditions that are relevant to the smoking of illicit cocaine by humans. For this purpose an aerobic pyrolysis device was developed and the experimental conditions were optimized. In the first part of our study the optimization of some basic experimental parameters of the pyrolysis was performed, i.e., the furnace temperature, the sampling start time, the heating period, the sampling time, and the air-flow rate through the system. The second part of the investigation focused on the volatile products formed during the pyrolysis of a pure cocaine free base and mixtures of cocaine base and adulterants. The anaesthetics lidocaine, benzocaine, procaine, the analgesics phenacetine and paracetamol, and the stimulant caffeine were used as the adulterants. Under the applied experimental conditions complete volatilization of the samples was achieved, i.e., the residuals of the studied compounds were not detected in the pyrolysis cell. Volatilization of the pure cocaine base showed that the cocaine recovery available for inhalation (adsorbed on traps) was approximately 76%. GC-MS and NMR analyses of the smoke condensate revealed the presence of some additional cocaine pyrolytic products, such as anhydroecgonine methyl ester (AEME), benzoic acid (BA) and carbomethoxycycloheptatrienes (CMCHTs). Experiments with different cocaine-adulterant mixtures showed that the addition of the adulterants changed the thermal behaviour of the cocaine. The most significant of these was the effect of paracetamol. The total recovery of the cocaine (adsorbed on traps and in a glass tube) from the 1:1 cocaine-paracetamol mixture was found to be only 3.0+/-0.8%, versus 81.4+/-2.9% for the pure cocaine base. The other adulterants showed less-extensive effects on the recovery of cocaine, but the pyrolysis of the cocaine-procaine mixture led to the formation of some unique pyrolytic products

  9. Biodegradation of alpha- and beta-hexachlorocyclohexane in a soil slurry under different redox conditions.

    PubMed Central

    Bachmann, A; Walet, P; Wijnen, P; de Bruin, W; Huntjens, J L; Roelofsen, W; Zehnder, A J

    1988-01-01

    Aerobic conditions proved to be best for the microbiol conversion of alpha-hexachlorocyclohexane (alpha-HCH) in a soil slurry. The dry soil contained 400 mg of alpha-HCH per kg. This xenobiotic compound was mineralized within about 18 days at an initial rate of 23 mg/kg of soil per day by the mixed native microbial population of the soil. The only intermediate that was detected during breakdown was pentachlorocyclohexene, which was detected at very small concentrations. Alpha-HCH was also bioconverted under methanogenic conditions. However, a rather long acclimation period (about 30 days) was necessary before degradation started, at a rate of 13 mg/kg of soil per day. Mass balance calculations showed that about 85% of the initial alpha-HCH that was present was converted to monochlorobenzene, 3,5-dichlorophenol, and a trichlorophenol isomer, possibly 2,4,5-trichlorophenol. Under both denitrifying and sulfate-reducing conditions, no significant bioconversion of alpha-HCH was observed. The beta isomer of HCH was recalcitrant at all of the four redox conditions studied. We propose that the specific spatial chloride arrangement of the beta isomer is responsible for its stability. The results reported here with complex soil slurry systems showed that alpha-HCH is, in contrast to the existing data in the literature, best degraded biologically in the presence of oxygen. PMID:2449868

  10. BIODEGRADATION KINETICS AND TOXICITY OF VEGETABLE OIL TRIACYLGLYCEROLS UNDER AEROBIC CONDITIONS

    EPA Science Inventory

    The aerobic biodegradation of five triacylglycerols (TAGs), three liquids [triolein (OOO), trilinolein (LLL), and trilinolenin (LnLnLn)] and two solids [tripalmitin (PPP) and tristearin (SSS)] was studied in water. Respirometry tests were designed and conducted to determine the b...

  11. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.; Baker, R.J.

    1999-01-01

    Aerobic biodegradation and volatilization near the water table constitute a coupled pathway that contributes significantly to the natural attenuation of hydrocarbons at gasoline spill sites. Rates of hydrocarbon biodegradation and volatilization were quantified by analyzing vapor transport in the unsaturated zone at a gasoline spill site in Beaufort, South Carolina. Aerobic biodegradation rates decreased with distance above the water table, ranging from 0.20 to 1.5g m-3 d-1 for toluene, from 0.24 to 0.38 g m-3 d-1 for xylene, from 0.09 to 0.24 g m-3 d-1 for cyclohexene, from 0.05 to 0.22 g m-3 d-1 for ethylbenzene, and from 0.02 to 0.08 g m-3 d-1 for benzene. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Hydrocarbons were nearly completely degraded within 1 m above the water table. This large loss underscores the importance of aerobic biodegradation in limiting the transport of hydrocarbon vapors in the unsaturated zone and implies that vapor-plume migration to basements and other points of contact may only be significant if a source of free product is present. Furthermore, because transport of the hydrocarbon in the unsaturated zone can be limited relative to that of oxygen and carbon dioxide, soil, gas surveys conducted at hydrocarbon-spill sites would benefit by the inclusion of oxygen- and carbon-dioxide-gas concentration measurements. Aerobic degradation kinetics in the unsaturated zone were approximately first-order. First-order rate constants near the water table were highest for cyctohexene (0.21-0.65 d-1) and nearly equivalent for ethylbenzene (0.11-20.31 d-1), xylenes (0.10-0.31 d-1), toluene (0.09-0.30 d-1), and benzene (0.07,0.31 d-1). Hydrocarbon mass loss rates at the water table resulting from the coupled aerobic biodegradation and volatilization process were determined by extrapolating gas transport rates through the capillary zone. Mass

  12. Aerobic bioremediation of chlorobenzene source-zone soil in flow-through columns: performance assessment using quantitative PCR.

    PubMed

    Dominguez, Rosa F; da Silva, Marcio L B; McGuire, Travis M; Adamson, David; Newell, Charles J; Alvarez, Pedro J J

    2008-07-01

    Flow-through aquifer columns were operated for 12 weeks to evaluate the benefits of aerobic biostimulation for the bioremediation of source-zone soil contaminated with chlorobenzenes (CBs). Quantitative Polymerase Chain Reaction (qPCR) was used to measure the concentration of total bacteria (16S rRNA gene) and oxygenase genes involved in the biodegradation of aromatic compounds (i.e., toluene dioxygenase, ring hydroxylating monooxygenase, naphthalene dioxygenase, phenol hydroxylase, and biphenyl dioxygenase). Monochlorobenzene, which is much more soluble than dichlorobenzenes, was primarily removed by flushing, and biostimulation showed little benefit. In contrast, dichlorobenzene removal was primarily due to biodegradation, and the removal efficiency was much higher in oxygen-amended columns compared to a control column. To our knowledge, this is the first report that oxygen addition can enhance CB source-zone soil bioremediation. Analysis by qPCR showed that whereas the biphenyl and toluene dioxygenase biomarkers were most abundant, increases in the concentration of the phenol hydroxylase gene reflected best the higher dichlorobenzene removal due to aerobic biostimulation. This suggests that quantitative molecular microbial ecology techniques could be useful to assess CB source-zone bioremediation performance.

  13. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  14. Bioconversion of 2,4-diamino-6-nitrotoluene to a novel metabolite under anoxic and aerobic conditions

    SciTech Connect

    Gilcrease, P.C.; Murphy, V.G.

    1995-12-01

    Under nitrate-reducing, nongrowth conditions, a Pseudomonas fluorescens species reduced 2,4,6-trinitrotoluene to aminodinitrotoluenes, which were then further reduced to diaminonitrotoluenes. 2,4-Diamino-6-nitrotoluene (2,4-DANT) was further transformed to a novel metabolite, 4-N-acetylamino-2-amino-6-nitrotoluene (4-N-AcANT), while 2,6-diamino-4-nitrotoluene (2,6-DANT) was persistent. Efforts to further degrade 2,4-DANT and 2,6-DANT under aerobic, nitrogen-limited conditions were unsuccessful; 2,6-DANT remained persistent, and 2,4-DANT was again transformed to the 4-N-AcANT compound.

  15. Bioconversion of 2,4-diamino-6-nitrotoluene to a novel metabolite under anoxic and aerobic conditions.

    PubMed Central

    Gilcrease, P C; Murphy, V G

    1995-01-01

    Under nitrate-reducing, nongrowth conditions, a Pseudomonas fluorescens species reduced 2,4,6-trinitrotoluene to aminodinitrotoluenes, which were then further reduced to diaminonitrotoluenes. 2,4-Diamino-6-nitrotoluene (2,4-DANT) was further transformed to a novel metabolite, 4-N-acetylamino-2-amino-6-nitrotoluene (4-N-AcANT), while 2,6-diamino-4-nitrotoluene (2,6-DANT) was persistent. Efforts to further degrade 2,4-DANT and 2,6-DANT under aerobic, nitrogen-limited conditions were unsuccessful; 2,6-DANT remained persistent, and 2,4-DANT was again transformed to the 4-N-AcANT compound. PMID:8534088

  16. Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions.

    PubMed

    Menahem, Adi; Dror, Ishai; Berkowitz, Brian

    2016-02-01

    The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions. PMID:26408978

  17. Molecular characterization of a microbial consortium involved in methane oxidation coupled to denitrification under micro-aerobic conditions

    PubMed Central

    Liu, Jingjing; Sun, Faqian; Wang, Liang; Ju, Xi; Wu, Weixiang; Chen, Yingxu

    2014-01-01

    Methane can be used as an alternative carbon source in biological denitrification because it is nontoxic, widely available and relatively inexpensive. A microbial consortium involved in methane oxidation coupled to denitrification (MOD) was enriched with nitrite and nitrate as electron acceptors under micro-aerobic conditions. The 16S rRNA gene combined with pmoA phylogeny of methanotrophs and nirK phylogeny of denitrifiers were analysed to reveal the dominant microbial populations and functional microorganisms. Real-time quantitative polymerase chain reaction results showed high numbers of methanotrophs and denitrifiers in the enriched consortium. The 16S rRNA gene clone library revealed that Methylococcaceae and Methylophilaceae were the dominant populations in the MOD ecosystem. Phylogenetic analyses of pmoA gene clone libraries indicated that all methanotrophs belonged to Methylococcaceae, a type I methanotroph employing the ribulose monophosphate pathway for methane oxidation. Methylotrophic denitrifiers of the Methylophilaceae that can utilize organic intermediates (i.e. formaldehyde, citrate and acetate) released from the methanotrophs played a vital role in aerobic denitrification. This study is the first report to confirm micro-aerobic denitrification and to make phylogenetic and functional assignments for some members of the microbial assemblages involved in MOD. PMID:24245852

  18. Optimization of operation conditions for preventing sludge bulking and enhancing the stability of aerobic granular sludge in sequencing batch reactors.

    PubMed

    Zhou, Jun; Wang, Hongyu; Yang, Kai; Ma, Fang; Lv, Bin

    2014-01-01

    Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

  19. Molecular characterization of a microbial consortium involved in methane oxidation coupled to denitrification under micro-aerobic conditions.

    PubMed

    Liu, Jingjing; Sun, Faqian; Wang, Liang; Ju, Xi; Wu, Weixiang; Chen, Yingxu

    2014-01-01

    Methane can be used as an alternative carbon source in biological denitrification because it is nontoxic, widely available and relatively inexpensive. A microbial consortium involved in methane oxidation coupled to denitrification (MOD) was enriched with nitrite and nitrate as electron acceptors under micro-aerobic conditions. The 16S rRNA gene combined with pmoA phylogeny of methanotrophs and nirK phylogeny of denitrifiers were analysed to reveal the dominant microbial populations and functional microorganisms. Real-time quantitative polymerase chain reaction results showed high numbers of methanotrophs and denitrifiers in the enriched consortium. The 16S rRNA gene clone library revealed that Methylococcaceae and Methylophilaceae were the dominant populations in the MOD ecosystem. Phylogenetic analyses of pmoA gene clone libraries indicated that all methanotrophs belonged to Methylococcaceae, a type I methanotroph employing the ribulose monophosphate pathway for methane oxidation. Methylotrophic denitrifiers of the Methylophilaceae that can utilize organic intermediates (i.e. formaldehyde, citrate and acetate) released from the methanotrophs played a vital role in aerobic denitrification. This study is the first report to confirm micro-aerobic denitrification and to make phylogenetic and functional assignments for some members of the microbial assemblages involved in MOD.

  20. Lignin decomposition and microbial community in paddy soils: effects of alternating redox conditions

    NASA Astrophysics Data System (ADS)

    Cerli, Chiara; Liu, Qin; Hanke, Alexander; Kaiser, Klaus; Kalbitz, Karsten

    2013-04-01

    Paddy soils are characterised by interchanging cycles of anaerobic and aerobic conditions. Such fluctuations cause continuous changes in soil solution chemistry as well as in the composition and physiological responses of the microbial community. Temporary deficiency in oxygen creates conditions favourable to facultative or obligates anaerobic bacteria, while aerobic communities can thrive in the period of water absence. These alterations can strongly affect soil processes, in particular organic matter (OM) accumulation and mineralization. In submerged soils, lignin generally constitutes a major portion of the total OM because of hampered degradation under anoxic conditions. The alternating redox cycles resulting from paddy soil management might promote both degradation and preservation of lignin, affecting the overall composition and reactivity of total and dissolved OM. We sampled soils subjected to cycles of anoxic (rice growing period) and oxic (harvest and growth of other crops) conditions since 700 and 2000 years. We incubated suspended Ap material, sampled from the two paddy plus two corresponding non-paddy control soils under oxic and anoxic condition, for 3 months, interrupted by a short period of three weeks (from day 21 to day 43) with reversed redox conditions. At each sampling time (day 2, 21, 42, 63, 84), we determined lignin-derived phenols (by CuO oxidation) as well as phospholipids fatty acids contents and composition. We aimed to highlight changes in lignin decomposition as related to the potential rapid changes in microbial community composition. Since the studied paddy soils had a long history of wet rice cultivation, the microbial community should be well adapted to interchanging oxic and anoxic cycles, therefore fully expressing its activity at both conditions. In non-paddy soil changes in redox conditions caused modification of quantity and composition of the microbial community. On the contrary, in well-established paddy soils the microbial

  1. Bacterially Induced Dolomite Formation in the Presence of Sulfate Ions under Aerobic Conditions

    NASA Astrophysics Data System (ADS)

    Sanchez-Roman, M.; McKenzie, J. A.; Vasconcelos, C.; Rivadeneyra, M.

    2005-12-01

    The origin of dolomite remains a long-standing enigma in sedimentary geology because, although thermodynamically favorable, precipitation of dolomite from modern seawater does not occur. Experiments conducted at elevated temperatures (200 oC) indicated that the presence of small concentrations of sulfate ions inhibits the transformation of calcite to dolomite [1]. Indeed, sulfate ions appeared to inhibit dolomite formation above 2 mM concentration (versus 28 mM in modern seawater). Recently, culture experiments have demonstrated that sulfate-reducing bacteria mediate the precipitation of dolomite at Earth surface conditions in the presence of sustained sulfate ion concentrations [2,3]. Additionally, in a number of modern hypersaline environments, dolomite forms from solutions with high sulfate ion concentrations (2 to 70 times seawater). These observations suggest that the experimentally observed sulfate-ion inhibition [1] may not apply to all ancient dolomite formation. Here, we report aerobic culture experiments conducted at low temperatures (25 and 35 oC) and variable sulfate ion concentrations (0, 0.5, 1 and 2 x seawater values) using moderately halophilic bacteria, Halomonas meridiana. After an incubation period of 15 days, experiments at 35 oC with variable sulfate ion concentrations (0, 0.5 x and seawater values) contained crystals of Ca-dolomite and stochiometric dolomite. The experiment at 35 oC with 2 x seawater sulfate ion concentration produced dolomite crystals after 20 days of incubation. In a parallel set of experiments at 25 oC, precipitation of dolomite was observed after 25 days of incubation in cultures with variable sulfate ion concentrations (0, 0.5 x and seawater values). In the culture with 2 x seawater sulfate ion concentration, dolomite crystals were observed after 30 days. Our study demonstrates that halophilic bacteria (or heterotrophic microorganisms), which do not require sulfate ions for metabolism, can mediate dolomite precipitation

  2. Aerobic biodegradation of [14C] 6:2 fluorotelomer alcohol in a flow-through soil incubation system.

    PubMed

    Liu, Jinxia; Wang, Ning; Buck, Robert C; Wolstenholme, Barry W; Folsom, Patrick W; Sulecki, Lisa M; Bellin, Cheryl A

    2010-08-01

    The aerobic biodegradation of [1,2-(14)C] 6:2 FTOH [F(CF(2))(6)(14)CH(2)(14)CH(2)OH] in a flow-through soil incubation system is described. Soil samples dosed with [1,2-(14)C] 6:2 FTOH were analyzed by liquid scintillation counting, LC/ARC (liquid chromatography/accurate radioisotope counting), LC/MS/MS, and thermal combustion to account for 6:2 FTOH and its transformation products over 84 d. Half of the [1,2-(14)C] 6:2 FTOH disappeared from soil in 1.3 d, undergoing simultaneous microbial degradation and partitioning of volatile transformation product(s) and the 6:2 FTOH precursor into the air phase. The overall (14)C (radioactivity) mass balance in live and sterile treatments was 77-87% over 84-d incubation. In the live test system, 36% of total (14)C dosed was captured in the airflow (headspace), 25% as soil-bound residues recovered via thermal combustion, and 16% as soil extractable. After 84 d, [(14)C] 5:2 sFTOH [F(CF(2))(5)CH(OH)(14)CH(3)] was the dominant transformation product with 16% molar yield and primarily detected in the airflow. The airflow also contained [1,2-(14)C] 6:2 FTOH and (14)CO(2) at 14% and 6% of total (14)C dosed, respectively. The other significant stable transformation products, all detected in soil, were 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH, 12%], PFHxA [F(CF(2))(5)COOH, 4.5%] and PFPeA [F(CF(2))(4)COOH, 4.2%]. Soil-bound residues as well as conjugates between fluorinated transformation products and dissolved soil components were only observed in the live test system and absent in the sterile soil, suggesting that such binding and complexation are microbially or enzymatically driven processes. At day 84, 5:3 acid is postulated to be the major transformation product in soil-bound residues, which may not be available for further biodegradation in soil environment.

  3. Construction of CoA-dependent 1-butanol synthetic pathway functions under aerobic conditions in Escherichia coli.

    PubMed

    Kataoka, Naoya; Vangnai, Alisa S; Pongtharangkul, Thunyarat; Tajima, Takahisa; Yakushi, Toshiharu; Matsushita, Kazunobu; Kato, Junichi

    2015-06-20

    1-Butanol is an important industrial platform chemical and an advanced biofuel. While various groups have attempted to construct synthetic pathways for 1-butanol production, efforts to construct a pathway that functions under aerobic conditions have met with limited success. Here, we constructed a CoA-dependent 1-butanol synthetic pathway that functions under aerobic conditions in Escherichia coli, by expanding the previously reported (R)-1,3-butanediol synthetic pathway. The pathway consists of phaA (acetyltransferase) and phaB (NADPH-dependent acetoacetyl-CoA reductase) from Ralstonia eutropha, phaJ ((R)-specific enoyl-CoA hydratase) from Aeromonas caviae, ter (trans-enoyl-CoA reductase) from Treponema denticola, bld (butylraldehyde dehydrogenase) from Clostridium saccharoperbutylacetonicum, and inherent alcohol dehydrogenase(s) from E. coli. To evaluate the potential of this pathway for 1-butanol production, culture conditions, including volumetric oxygen transfer coefficient (kLa) and pH were optimized in a mini-jar fermenter. Under optimal conditions, 1-butanol was produced at a concentration of up to 8.60gL(-1) after 46h of fed-batch cultivation.

  4. Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

    SciTech Connect

    Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C; Coleman, M A

    2006-04-22

    Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.

  5. A laboratory study of the bioremediation of 2,4,6-trinitrotoluene-contaminated soil using aerobic/anoxic soil slurry reactor.

    SciTech Connect

    Boopathy, R.; Manning, J.; Kulpa, C. F.; Environmental Research; Univ. of Notre Dame

    1998-01-01

    The successful operation of an aerobic/anoxic laboratory-scale soil slurry reactor showed that soil contaminated with 2,4,6-trinitrotoluene (TNT) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) could be treated in batches or semicontinuously. Batch treatment resulted in the transformation of TNT. Semicontinuous treatment resulted in complete degradation of TNT. In addition to removing TNT, the slurry reactor also removed contaminants such as trinitrobenzene, 2,4-dinitrotoluene, RDX, and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetraazocine (HMX). Radiolabeled TNT incubated with reactor biomass showed that 23% of [{sup 14}C]TNT was mineralized, 27% was converted to biomass, and 8% was adsorbed onto the soil. The rest of the [{sup 14}C]TNT was accounted for as metabolites, including a ring cleavage product identified as 2,3-butanediol. Increasing the frequency of soil addition from once to two or three times weekly did not affect the TNT removal rates. The soil slurry reactor also maintained the bacterial population fairly well, needing only 0.3% molasses as a cosubstrate.

  6. Aerobic biotransformation of N-nitrosodimethylamine and N-nitrodimethylamine in methane and benzene amended soil columns.

    PubMed

    Weidhaas, Jennifer; Dupont, R Ryan

    2013-07-01

    Aerobic biotransformation of N-nitrosodimethylamine (NDMA), an emerging contaminant of concern, and its structural analog N-nitrodimethylamine (DMN), was evaluated in benzene and methane amended groundwater passed through laboratory scale soil columns. Competitive inhibition models were used to model the kinetics for NDMA and DMN cometabolism accounting for the concurrent degradation of the growth and cometabolic substrates. Transformation capacities for NDMA and DMN with benzene (13 and 23μg (mgcells)(-1)) and methane (0.14 and 8.4μg (mgcells)(-1)) grown cultures, respectively are comparable to those presented in the literature, as were first order endogenous decay rates estimated to be 2.1×10(-2)±1.7×10(-3)d(-1) and 6.5×10(-1)±7.1×10(-1)d(-1) for the methane and benzene amended cultures, respectively. These studies highlight possible attenuation mechanisms and rates for NDMA and DMN biotransformation in aerobic aquifers undergoing active remediation, natural attenuation or managed aquifer recharge with treated wastewater (i.e., reclaimed water).

  7. Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide- and metal-contaminated subsurface soils.

    PubMed

    Martinez, Robert J; Beazley, Melanie J; Taillefert, Martial; Arakaki, Adrian K; Skolnick, Jeffrey; Sobecky, Patricia A

    2007-12-01

    In this study, the immobilization of toxic uranium [U(VI)] mediated by the intrinsic phosphatase activities of naturally occurring bacteria isolated from contaminated subsurface soils was examined. The phosphatase phenotypes of strains belonging to the genera, Arthrobacter, Bacillus and Rahnella, previously isolated from subsurface soils at the US Department of Energy's (DOE) Oak Ridge Field Research Center (ORFRC), were determined. The ORFRC represents a unique, extreme environment consisting of highly acidic soils with co-occurring heavy metals, radionuclides and high nitrate concentrations. Isolates exhibiting phosphatase-positive phenotypes indicative of constitutive phosphatase activity were subsequently tested in U(VI) bioprecipitation assays. When aerobically grown in synthetic groundwater (pH 5.5) amended with 10 mM glycerol-3-phosphate (G3P), phosphatase-positive Bacillus and Rahnella spp. strains Y9-2 and Y9602 liberated sufficient phosphate to precipitate 73% and 95% of total soluble U added as 200 microM uranyl acetate respectively. In contrast, an Arthrobacter sp. X34 exhibiting a phosphatase-negative phenotype did not liberate phosphate from G3P or promote U(VI) precipitation. This study provides the first evidence of U(VI) precipitation via the phosphatase activity of naturally occurring Bacillus and Rahnella spp. isolated from the acidic subsurface at the DOE ORFRC.

  8. New generic mathematical model for WWTP sludge digesters operating under aerobic and anaerobic conditions: Model building and experimental verification.

    PubMed

    de Gracia, M; Grau, P; Huete, E; Gómez, J; García-Heras, J L; Ayesa, E

    2009-10-01

    This paper presents a new mathematical model developed to reproduce the performance of a generic sludge digester working either under aerobic or anaerobic operational conditions. The digester has been modelled as two completely mixed tanks associated with gaseous and liquid volumes. The conversion model has been developed based on a plant wide modelling methodology (PWM) and comprises biochemical transformations, physicochemical reactions and thermodynamic considerations. The model predicts the reactor temperature and the temporary evolution of an extensive vector of model components which are completely defined in terms of elemental mass fractions (C, H, O, N and P) and charge density. Thus, the comprehensive definition of the model components guarantees the continuity of elemental mass and charge in all the model transformations and between any two systems defined by the model. The aim of the generic digester model is to overcome the problems that arise when trying to connect aerobic and anaerobic digestion processes working in series or to connect water and sludge lines in a WWTP. The modelling methodology used has allowed the systematic construction of the biochemical model which acts as an initial illustrative example of an application that has been experimentally verified. The variation of the temperature is also predicted based on a thermal dynamic model. Real data from four different facilities and a straightforward calibration have been used to successfully verify the model predictions in the cases of mesophilic and thermophilic anaerobic digestion as well as autothermal thermophilic aerobic digestion (ATAD). The large amount of data from the full scale ATAD and the anaerobic digestion pilot plants, all of them working under different conditions, has allowed the validation of the model for that case study. PMID:19720390

  9. Fate of Pharmaceuticals and Personal Care Products (PPCPs) in Saturated Soil Under Various Redox Conditions

    NASA Astrophysics Data System (ADS)

    Dror, I.; Menahem, A.; Berkowitz, B.

    2014-12-01

    The growing use of PPCPs results in their increasing release to the aquatic environment. Consequently, understanding the fate of PPCPs under environmentally relevant conditions that account for dynamic flow and varying redox states is critical. In this study, the transport of two organometallic PPCPs, Gd-DTPA and Roxarsone (As complex) and their metal salts (Gd(NO3)3, AsNaO2), is investigated. The former is used widely as a contrasting agent for MRI, while the latter is applied extensively as a food additive in the broiler poultry industry. Both of these compounds are excreted from the body, almost unchanged chemically. Gadolinium complexes are not fully eliminated in wastewater treatment and can reach groundwater via irrigation with treated wastewater; Roxarsone can enter groundwater via leaching from manure used as fertilizer. Studies have shown that the transport of PPCPs in groundwater is affected by environmental conditions such as redox states, pH, and soil type. For this study, column experiments using sand or Mediterranean red sandy clay soil were performed under several redox conditions: aerobic, nitrate-reducing, iron-reducing, sulfate-reducing, methanogenic, and very strongly chemical reducing. Batch experiments to determine adsorption isotherms were also performed for the complexes and metal salts. We found that Gd-DTPA transport was affected by the soil type and was not affected by the redox conditions. In contrast, Roxarsone transport was affected mainly by the different redox conditions, showing delayed breakthrough curves as the conditions became more biologically reduced (strong chemical reducing conditions did not affect the transport). We also observed that the metal salts show essentially no transport while the organic complexes display much faster breakthrough. The results suggest that transport of these PPCPs through soil and groundwater is determined by the redox conditions, as well as by soil type and the form of the applied metal (as salt

  10. Interaction between phosphorus removal and hybrid granular sludge formation under low hydraulic selection pressure at alternating anaerobic/aerobic conditions.

    PubMed

    Lang, Longqi; Wan, Junfeng; Zhang, Jing; Wang, Jie; Wang, Yan

    2015-01-01

    The hybrid granular sludge (HGS) formation and its performances on phosphorus removal were investigated in a sequencing batch airlift reactor. Under conditions of low superficial air velocity (SAV = 0.68 cm s(-1)) and relatively long settling time (15-30 min), aerobic granules appeared and coexisted with bio-flocs after 120 days operation. At the stable phase, 54% of total suspended solid (m/m) was granular sludge with the two typical sizes (D(mean) = 1.77 ± 0.33 and 0.89 ± 0.11 mm) in the reactor, where the settling velocity was 98.7 ± 12.4 and 37.8 ± 0.9 m h(-1) for the big and small granules. With progressive extension of anaerobic time from 15 to 60 min before aerobic condition per cycle during the whole experiment, the HGS system can be maintained at a high total phosphorus removal efficiency (ca. 99%) since Day-270. The phosphorus content (wt %) in biomass was respectively 9.54 ± 0.29, 7.60 ± 0.48 and 6.15 ± 0.59 for the big granules, small granules and flocs.

  11. Characterization of the Enterobacteriaceae community that developed during storage of minced beef under aerobic or modified atmosphere packaging conditions.

    PubMed

    Doulgeraki, Agapi I; Paramithiotis, Spiros; Nychas, George-John E

    2011-01-31

    The whole cell protein and macrorestriction analysis of DNA of Enterobacteriaceae isolates recovered from minced beef stored at 0, 5, 10 and 15 °C aerobically and under modified atmosphere packaging consisting of 40% CO(2)-30% O(2)-30% N(2) in the presence (MAP+) and absence (MAP-) of oregano essential oil were studied. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profiles obtained from whole cell protein analysis of the Enterobacteriaceae isolates revealed seven groups. Moreover, application of a modified PFGE protocol with XbaI restriction, resulted into 19 different fingerprints. The Enterobacteriaceae community of fresh meat consisted of Serratia liquefaciens and Serratia proteamaculans. S. liquefaciens strain VK23 was the dominant isolate of Enterobacteriaceae for the most conditions adopted, except 10 °C and 15 °C under MAP + and 10 °C under MAP-. In the latter cases, Hafnia alvei represented the dominant fingerprint. Citrobacter freundii was recovered from minced beef stored aerobically, while H. alvei and Proteus vulgaris were recovered under MAP. Storage conditions affected the Enterobacteriaceae community; modified atmosphere packaging increased both species and strain diversity. PMID:21216482

  12. Dietary citrus pulp improves protein stability in lamb meat stored under aerobic conditions.

    PubMed

    Gravador, Rufielyn S; Jongberg, Sisse; Andersen, Mogens L; Luciano, Giuseppe; Priolo, Alessandro; Lund, Marianne N

    2014-06-01

    The antioxidant effects of dried citrus pulp on proteins in lamb meat, when used as a replacement of concentrate in the feed, was studied using meat from 26 male Comisana lambs. The lambs of age 90 days had been grouped randomly to receive one of the three dietary treatments: (1) commercial concentrate with 60% barley (Control, n=8), (2) concentrate with 35% barley and 24% citrus pulp (Cp24, n=9), or (3) concentrate with 23% barley and 35% citrus pulp (Cp35, n=9). Slices from the longissimus thoracis et lomborum muscle were packed aerobically and stored for up to 6days at 4°C in the dark. The citrus pulp groups, Cp24 and Cp35, significantly decreased protein radicals and carbonyls, and preserved more thiols within six days of storage compared to the Control group. The citrus pulp groups significantly slowed down the rate of protein oxidation, indicating that dietary citrus pulp reduced oxidative changes in meat proteins.

  13. Adhesion, Biofilm Formation, and Genomic Features of Campylobacter jejuni Bf, an Atypical Strain Able to Grow under Aerobic Conditions.

    PubMed

    Bronnec, Vicky; Turoňová, Hana; Bouju, Agnès; Cruveiller, Stéphane; Rodrigues, Ramila; Demnerova, Katerina; Tresse, Odile; Haddad, Nabila; Zagorec, Monique

    2016-01-01

    Campylobacter jejuni is the leading cause of bacterial enteritis in Europe. Human campylobacteriosis cases are frequently associated to the consumption of contaminated poultry meat. To survive under environmental conditions encountered along the food chain, i.e., from poultry digestive tract its natural reservoir to the consumer's plate, this pathogen has developed adaptation mechanisms. Among those, biofilm lifestyle has been suggested as a strategy to survive in the food environment and under atmospheric conditions. Recently, the clinical isolate C. jejuni Bf has been shown to survive and grow under aerobic conditions, a property that may help this strain to better survive along the food chain. The aim of this study was to evaluate the adhesion capacity of C. jejuni Bf and its ability to develop a biofilm. C. jejuni Bf can adhere to abiotic surfaces and to human epithelial cells, and can develop biofilm under both microaerobiosis and aerobiosis. These two conditions have no influence on this strain, unlike results obtained with the reference strain C. jejuni 81-176, which harbors only planktonic cells under aerobic conditions. Compared to 81-176, the biofilm of C. jejuni Bf is more homogenous and cell motility at the bottom of biofilm was not modified whatever the atmosphere used. C. jejuni Bf whole genome sequence did not reveal any gene unique to this strain, suggesting that its unusual property does not result from acquisition of new genetic material. Nevertheless some genetic particularities seem to be shared only between Bf and few others strains. Among the main features of C. jejuni Bf genome we noticed (i) a complete type VI secretion system important in pathogenicity and environmental adaptation; (ii) a mutation in the oorD gene involved in oxygen metabolism; and (iii) the presence of an uncommon insertion of a 72 amino acid coding sequence upstream from dnaK, which is involved in stress resistance. Therefore, the atypical behavior of this strain under

  14. Adhesion, Biofilm Formation, and Genomic Features of Campylobacter jejuni Bf, an Atypical Strain Able to Grow under Aerobic Conditions

    PubMed Central

    Bronnec, Vicky; Turoňová, Hana; Bouju, Agnès; Cruveiller, Stéphane; Rodrigues, Ramila; Demnerova, Katerina; Tresse, Odile; Haddad, Nabila; Zagorec, Monique

    2016-01-01

    Campylobacter jejuni is the leading cause of bacterial enteritis in Europe. Human campylobacteriosis cases are frequently associated to the consumption of contaminated poultry meat. To survive under environmental conditions encountered along the food chain, i.e., from poultry digestive tract its natural reservoir to the consumer’s plate, this pathogen has developed adaptation mechanisms. Among those, biofilm lifestyle has been suggested as a strategy to survive in the food environment and under atmospheric conditions. Recently, the clinical isolate C. jejuni Bf has been shown to survive and grow under aerobic conditions, a property that may help this strain to better survive along the food chain. The aim of this study was to evaluate the adhesion capacity of C. jejuni Bf and its ability to develop a biofilm. C. jejuni Bf can adhere to abiotic surfaces and to human epithelial cells, and can develop biofilm under both microaerobiosis and aerobiosis. These two conditions have no influence on this strain, unlike results obtained with the reference strain C. jejuni 81-176, which harbors only planktonic cells under aerobic conditions. Compared to 81-176, the biofilm of C. jejuni Bf is more homogenous and cell motility at the bottom of biofilm was not modified whatever the atmosphere used. C. jejuni Bf whole genome sequence did not reveal any gene unique to this strain, suggesting that its unusual property does not result from acquisition of new genetic material. Nevertheless some genetic particularities seem to be shared only between Bf and few others strains. Among the main features of C. jejuni Bf genome we noticed (i) a complete type VI secretion system important in pathogenicity and environmental adaptation; (ii) a mutation in the oorD gene involved in oxygen metabolism; and (iii) the presence of an uncommon insertion of a 72 amino acid coding sequence upstream from dnaK, which is involved in stress resistance. Therefore, the atypical behavior of this strain under

  15. Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity.

    PubMed

    Chibwe, Leah; Geier, Mitra C; Nakamura, Jun; Tanguay, Robert L; Aitken, Michael D; Simonich, Staci L Massey

    2015-12-01

    The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (prebioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (postbioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, postbioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, postbioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, postbioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and postbioremediation. The increased toxicity measured postbioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase postbioremediation. However, the increased toxicity measured postbioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1

  16. Phosphorus Release to Floodwater from Calcareous Surface Soils and Their Corresponding Subsurface Soils under Anaerobic Conditions.

    PubMed

    Jayarathne, P D K D; Kumaragamage, D; Indraratne, S; Flaten, D; Goltz, D

    2016-07-01

    Enhanced phosphorus (P) release from soils to overlying water under flooded, anaerobic conditions has been well documented for noncalcareous and surface soils, but little information is available for calcareous and subsurface soils. We compared the magnitude of P released from 12 calcareous surface soils and corresponding subsurface soils to overlying water under flooded, anaerobic conditions and examined the reasons for the differences. Surface (0-15 cm) and subsurface (15-30 cm) soils were packed into vessels and flooded for 8 wk. Soil redox potential and concentrations of dissolved reactive phosphorus (DRP) and total dissolved Ca, Mg, Fe, and Mn in floodwater and pore water were measured weekly. Soil test P was significantly smaller in subsurface soils than in corresponding surface soils; thus, the P release to floodwater from subsurface soils was significantly less than from corresponding surface soils. Under anaerobic conditions, floodwater DRP concentration significantly increased in >80% of calcareous surface soils and in about 40% of subsurface soils. The increase in floodwater DRP concentration was 2- to 17-fold in surface soils but only 4- to 7-fold in subsurface soils. With time of flooding, molar ratios of Ca/P and Mg/P in floodwater increased, whereas Fe/P and Mn/P decreased, suggesting that resorption and/or reprecipitation of P took place involving Fe and Mn. Results indicate that P release to floodwater under anaerobic conditions was enhanced in most calcareous soils. Surface and subsurface calcareous soils in general behaved similarly in releasing P under flooded, anaerobic conditions, with concentrations released mainly governed by initial soil P concentrations. PMID:27380087

  17. Differential sensitivities of the growth of Escherichia coli to acrylate under aerobic and anaerobic conditions and its effect on product formation.

    PubMed

    Arya, Ajay S; Lee, Sarah A; Eiteman, Mark A

    2013-11-01

    The effect of acrylate on the growth of Escherichia coli was determined under aerobic and anaerobic conditions in glucose-defined medium. Growth occurred with up to 35 mM acrylate under aerobic conditions but ceased at 5 mM acrylate under anaerobic conditions. This differential sensitivity can be attributed to inhibition of pyruvate formate lyase and/or pflB gene repression, as this enzyme is necessary for anaerobic growth of E. coli. The effect of acrylate on end-product distribution was also determined by growing E. coli first aerobically, then switching to anaerobic conditions. In the absence of acrylate, E. coli generated the typical distribution of mixed-acid products, with about 12 % of pyruvate being metabolically converted to lactate. In contrast, in the presence of 5 mM acrylate, E. coli converted 83 % of pyruvate to lactate, consistent with a reduction in pyruvate formate lyase activity.

  18. Interaction of Cr(VI) reduction and denitrification by strain Pseudomonas aeruginosa PCN-2 under aerobic conditions.

    PubMed

    He, Da; Zheng, Maosheng; Ma, Tao; Li, Can; Ni, Jinren

    2015-06-01

    Inhibition of efficient denitrification in presence of toxic heavy metals is one of the current problems encountered in municipal wastewater treatment plants. This paper presents how to remove hexavalent chromium (Cr(VI)) and nitrate simultaneously by the novel strain Pseudomonas aeruginosa PCN-2 under aerobic conditions. The capability of strain PCN-2 for Cr(VI) and nitrate reduction was confirmed by PCR analysis of gene ChrR, napA, nirS, cnorB, nosZ, while Cr(VI) reduction was proved via an initial single-electron transfer through Cr(V) detection using electron paramagnetic resonance. Experimental results demonstrated that Cr(VI) and nitrate reduction by strain PCN-2 was much faster at pH 8-9 and higher initial cell concentration. However, increasing Cr(VI) concentration would inhibit aerobic denitrification process and result in an significant delay of nitrate reduction or N2O accumulation, which was attributed to competition between three electron acceptors, i.e., Cr(VI), O2 and nitrate in the electron transport chain.

  19. Bioaugmented composting of Jatropha de-oiled cake and vegetable waste under aerobic and partial anaerobic conditions.

    PubMed

    Chaturvedi, Shivani; Kumar, Ashwani; Singh, Balraj; Nain, Lata; Joshi, Monica; Satya, Santosh

    2013-04-01

    This study was conducted to assess the effect of microbial inoculation in Jatropha cake composting with different vegetable waste. The microbial inoculums composed of fungal strains (Aspergillus awamori, Aspergillus nidulans, Trichoderma viride, Phanerochaete chrysosporium) and bacterial inoculums (Pseudomonas striata as phosphorus solublizer and Azotobacter chroococcum as nitrogen fixer) were added to the compost mixture after the thermophilic phase was over for bioaugmenting of Jatropha cake under aerobic and partial anaerobic conditions. Addition of both fungal and bacterial inoculum with mixed substrate (Jatropha cake + vegetable waste) during composting (aerobic and partial anaerobic) showed, better results as compared to compost with only fungal inoculants. Increased enzymatic activity initially, during composting (like dehydrogenase, alkaline phosphatase activity and FDA) proved role of inoculated microbes in rapid decomposition. Analysis of compost (with both bacterial and fungal inoculum) showed presence of high humus (12.7%), humic acid (0.5%), fulvic acid (5.68%), soluble protein content and low C/N ratio. Decreased in concentration of extractable metals (Cu, Fe and Mn) were recorded at maturity in all the substrate composts. The C/N ratio was significantly correlated to parameters like humic acid, humus, fulvic acid, protein and also microbial activity parameters. We conclude that the composting of de-oiled Jatropha cake with different vegetables waste could be feasible and sustainable approach in recycling of agricultural and industrial residues in huge quantities.

  20. Mechanisms involved in soil conditioning by polymers

    SciTech Connect

    Wallace, A.; Wallace, G.A.; Cha, J.W.

    1986-05-01

    Three different soils (two sodic and calcareous and one very acid and serpentine-like) was mixed with polyanion and polycation polymers and with a polysaccharide in suspension and passed the flocculated particles through sieves of different size openings for measurement of components. Including (NH/sub 4/)/sub 2/SO/sub 4/ in the suspension resulted in more complete flocculation with high pH soils and less with the acid soil. In contrast, with the polycation the (NH/sub 4/)/sub 2/SO/sub 4/ resulted in less flocculation for all three soils. Liming the acid soil to pH 7 increased flocculation for both the polyanion and the polycation. The polyanion resulted in more flocculation on calcareous than on acid soil, and the reverse occurred for the polycation. These results indicate that the salt effect was that of bringing clay particles closely enough together so that several of them could be bound with a common polyanion. The binding then would occur many times with polyanions for each aggregate of clay particles. Ion bridging is an important phenomenon in which polyvalent cations may be shared with polymer and clay in the flocculation-aggregation process. The addition of a polysaccharide with the polyanion gives additive to synergistic responses, indicating that there is cross-linking between the two polymers. The total effect resembles a brush heap that secures stability for the flocculated particles.

  1. Transcript profiles in cortical cells of maize primary root during ethylene-induced lysigenous aerenchyma formation under aerobic conditions

    PubMed Central

    Takahashi, Hirokazu; Yamauchi, Takaki; Rajhi, Imene; Nishizawa, Naoko K.; Nakazono, Mikio

    2015-01-01

    Background and Aims Internal aeration is important for plants to survive during periods of waterlogging, and the ability to form aerenchyma contributes by creating a continuous gas space between the shoots and the roots. Roots of maize (Zea mays) react to prolonged waterlogging by forming aerenchyma in root cortical cells by programmed cell death (PCD) in response to ethylene. The aim of this study was to understand the molecular mechanisms of ethylene-induced aerenchyma formation by identifying genes that are either up- or downregulated by ethylene treatment in maize root cortical cells. Methods Three-day-old maize seedlings were treated with ethylene for several hours under aerobic conditions. Cortical cells were isolated from the primary roots using laser microdissection (LM), and transcript profiles with and without ethylene treatment were compared by microarray. In addition, the effect on ethylene-induced aerenchyma formation of diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases, was examined in order to assess the involvement of reactive oxygen species (ROS). Key Results A total of 223 genes were identified whose transcript levels were significantly increased or decreased by ethylene treatment in root cortical cells under aerobic conditions. Subsequent tissue-specific quantitative reverse-transcription PCR analyses revealed that ethylene increased the transcript levels of genes related to ethylene signalling in all of the root tissues examined (stelar cells, cortical cells and outer cell layers), whereas it increased the transcript levels of genes related to cell wall modification and proteolysis specifically in the cortical cells. DPI treatment inhibited the ethylene-induced aerenchyma formation and suppressed expression of some cell wall modification-related genes. Conclusions Several genes related to cell wall modification and proteolysis are specifically up- or downregulated in cortical cells during lysigenous aerenchyma formation under aerobic

  2. Arsenic distribution and speciation near rice roots influenced by iron plaques and redox conditions of the soil matrix.

    PubMed

    Yamaguchi, Noriko; Ohkura, Toshiaki; Takahashi, Yoshio; Maejima, Yuji; Arao, Tomohito

    2014-01-01

    Elevated arsenic (As) concentrations in rice and the soil solution result from changes in soil redox conditions, influenced by the water management practices during rice cultivation. Microscale changes in redox conditions from rhizosphere to soil matrix affect the As speciation and Fe plaque deposition. In order to focus on the rhizosphere environment, we observed microscale distribution and speciation of As around the rhizosphere of paddy rice with X-ray fluorescence mapping and X-ray absorption spectroscopy. When the soil matrix was anaerobic during rice growth, Fe-plaque did not cover the entire root, and As(III) was the dominant arsenic species in the soil matrix and rhizosphere. Draining before harvest led the conditions to shift to aerobic. Oxidation of As(III) to As(V) occurred faster in the Fe-plaque than the soil matrix. Arsenic was scavenged by iron mottles originating from Fe-plaque around the roots. The ratio of As(V) to As(III) decreased toward the outer-rim of the subsurface Fe mottles where the soil matrix was not completely aerated. These results provide direct evidence that speciation of As near rice roots depends on spatial and temporal redox variations in the soil matrix. PMID:24384039

  3. Diastereoselective metabolism of a novel cis-nitromethylene neonicotinoid paichongding in aerobic soils.

    PubMed

    Fu, Qiuguo; Zhang, Jianbo; Xu, Xiaoyong; Wang, Haiyan; Wang, Wei; Ye, Qingfu; Li, Zhong

    2013-09-17

    Many pesticides are chiral but used as racemic mixtures, even though their stereoisomers are often degraded stereoselectively in soils. Evaluation of degradation of chiral compounds is mostly focused on the enantioselectivity rather than diastereoselectivity/epimer preferences. In this study, we explored the diastereoselective transformation of paichongding (IPP), a novel chiral neonicotinoid with broad-spectrum insecticidal activity, to several degradation intermediates in different soils. (14)C-Labeling coupled with LC-MS/MS and high resolution MS were used to track residues of IPP and identify major transformation metabolites. The stereoisomers of IPP known as 5R, 7R-IPP (RR-IPP), 5S, 7S-IPP (SS-IPP), 5S, 7R-IPP (SR-IPP), and 5R, 7S-IPP (RS-IPP) showed diastereoselective/epimer-selective persistence in all soils except an acidic clay soil. Moreover, IPP was transformed to a range of degradation intermediates (M1-M6), which also showed significant diastereoselective and soil preferential formation. Depropylation, nitrosylation, denitration, demethylation, dehydroxylation, and ketonization contributed to IPP transformation. The diastereoselective degradation of the parent compound and formation of incomplete intermediates implies that diastereomers/epimers should be regarded as different chemicals. The approach of coupling (14)C and MS may be used as an effective tool to understand the environmental processes and risks of other man-made chiral compounds. PMID:23924365

  4. Dissipation of phenanthrene and pyrene at the aerobic-anaerobic soil interface: differentiation induced by the rhizosphere of PAH-tolerant and PAH-sensitive rice (Oryza sativa L.) cultivars.

    PubMed

    He, Yan; Xia, Wen; Li, Xinfeng; Lin, Jiajiang; Wu, Jianjun; Xu, Jianming

    2015-03-01

    A pot experiment was conducted to reveal the removal of two polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, PHE, and pyrene, PYR) during rice cultivation in a paddy field. The rhizosphere effect on facilitating dissipation of PAHs varied simultaneously as a function of soil properties, PAH types, cultivation time, and genotypes within rice cultivars, with differences performed for PYR but not PHE. Changes in soil PLFA profiles evidenced that the growth of rice roots modified the dominant species within rhizosphere microbial communities and induced a selective enrichment of Gram-negative aerobic bacteria capable of degrading, thereby resulting in the differentiated dissipation of PYR. While the insignificant differences in PHE dissipation might be attributed to its higher solubility and availability under flooded condition that concealed the differences in improvement of bioavailability for microorganisms between rhizosphere and non-rhizosphere, and between both soils and both rice cultivars. Our findings illustrate that the removal of PAHs in paddy soils was more complex relative to those in dryland soils. This was possibly due to the specialty of rice roots for oxygen secretion that provides development of redox heterogeneous microbial habitats at root-soil interface under flooded condition.

  5. Light-Driven Hydrogen Production by Hydrogenases and a Ru-Complex inside a Nanoporous Glass Plate under Aerobic External Conditions.

    PubMed

    Noji, Tomoyasu; Kondo, Masaharu; Jin, Tetsuro; Yazawa, Tetsuo; Osuka, Hisao; Higuchi, Yoshiki; Nango, Mamoru; Itoh, Shigeru; Dewa, Takehisa

    2014-07-17

    Hydrogenases are powerful catalysts for light-driven H2 production using a combination of photosensitizers. However, except oxygen-tolerant hydrogenases, they are immediately deactivated under aerobic conditions. We report a light-driven H2 evolution system that works stably even under aerobic conditions. A [NiFe]-hydrogenase from Desulfovibrio vulgaris Miyazaki F was immobilized inside nanoporous glass plates (PGPs) with a pore diameter of 50 nm together with a ruthenium complex and methyl viologen as a photosensitizer and an electron mediator, respectively. After immersion of PGP into the medium containing the catalytic components, an anaerobic environment automatically established inside the nanopores even under aerobic external conditions upon irradiation with solar-simulated light; this system constantly evolved H2 with an efficiency of 3.7 μmol H2 m(-2) s(-1). The PGP system proposed in this work represents a promising first step toward the development of an O2-tolerant solar energy conversion system.

  6. Effects of redox conditions on the adsorption of dissolved organic matter to soil minerals and differently aged paddy soils

    NASA Astrophysics Data System (ADS)

    Sauerwein, Meike; Hanke, Alexander; Kaiser, Klaus; Kalbitz, Karsten

    2010-05-01

    Effects of redox conditions on the adsorption of dissolved organic matter to soil minerals and differently aged paddy soils Meike Sauerwein1, Alexander Hanke2, Klaus Kaiser3, Karsten Kalbitz2 1) Dept. of Soil Ecology, Bayreuth Centre of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany, meike.sauerwein@gmail.com 2) Institute of ecosystem dynamics and biodiversity, University of Amsterdam, 1018 WV, Netherlands, a.hanke@uva.nl, k.kalbitz@uva.nl 3) Soil Sciences, Martin Luther University Halle, 06099 Halle, Germany, klaus.kaiser@landw.uni-halle.de Current knowledge on dissolved organic matter (DOM) in soils is based mainly on observations and experiments in aerobic environments. Adsorption to soil minerals is an important mechanism of DOM retention and stabilization against microbial decay under oxic conditions. Under anoxic conditions where hydrous iron oxides, the potential main adsorbents of DOM, possibly dissolve, the importance of adsorption seems questionable. Therefore, we studied the adsorption of DOM to selected soil minerals and to mineral soils under oxic and anoxic conditions. In detail, we tested the following hypotheses: 1. Minerals and soils adsorb less DOM under anoxic conditions than under oxic ones. 2. The reduced adsorption under anoxic conditions is result of the smaller adsorption to hydrous Fe oxides whereas adsorption to clay minerals and Al hydroxides is not sensitive to changes in redox conditions 3. DOM adsorption will increase with the number of redox cycles, thus time of soil formation, due to increasing contents of poorly crystalline Fe oxides. This will, however, cause a stronger sensitivity to redox changes as poor crystalline Fe oxides are more reactive. 4. Aromatic compounds, being preferentially adsorbed under oxic conditions, will be less strongly adsorbed under anoxic conditions. We chose paddy soils as models because their periodically and regular exposure to changing redox cycles, with

  7. Effects of microbial inoculants on corn silage fermentation, microbial contents, aerobic stability, and milk production under field conditions.

    PubMed

    Kristensen, N B; Sloth, K H; Højberg, O; Spliid, N H; Jensen, C; Thøgersen, R

    2010-08-01

    The present study aimed to investigate the effects of 2 corn silage inoculation strategies (homofermentative vs. heterofermentative inoculation) under field conditions and to monitor responses in silage variables over the feeding season from January to August. Thirty-nine commercial dairy farms participated in the study. Farms were randomly assigned to 1 of 3 treatments: control (nonactive carrier; Chr. Hansen A/S, Hørsholm, Denmark), Lactisil (inoculation with 1 x 10(5)Lactobacillus pentosus and 2.5 x 10(4)Pediococcus pentosaceus per gram of fresh matter; Chr. Hansen A/S), and Lalsil Fresh (inoculation with 3 x 10(5)Lactobacillus buchneri NCIMB 40788 per gram of fresh matter; Lallemand Animal Nutrition, Blagnac, France). Inoculation with Lactisil had no effects on fermentation variables and aerobic stability. On the contrary, inoculation with Lalsil Fresh doubled the aerobic stability: 37, 38, and 80+/-8h for control, Lactisil, and Lalsil Fresh, respectively. The effect of Lalsil Fresh on aerobic stability tended to differ between sampling times, indicating a reduced difference between treatments in samples collected in April. Lalsil Fresh inoculation increased silage pH and contents of acetic acid, propionic acid, propanol, propyl acetate, 2-butanol, propylene glycol, ammonia, and free AA. The contents and ratios of DL-lactic acid, L-lactic acid relative to DL-lactic acid, free glucose, and DL-lactic acid relative to acetic acid decreased with Lalsil Fresh inoculation. Lalsil Fresh inoculation increased the silage counts of total lactic acid bacteria and reduced yeast counts. The Fusarium toxins deoxynivalenol, nivalenol, and zearalenone were detected in all silages at all collections, but the contents were not affected by ensiling time or by inoculation treatment. The effect of inoculation treatments on milk production was assessed by collecting test-day results from the involved farms and comparing the actual milk production with predicted milk production

  8. Biodegradation of benzene by halophilic and halotolerant bacteria under aerobic conditions.

    PubMed

    Nicholson, Carla A; Fathepure, Babu Z

    2004-02-01

    A highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production facility in Oklahoma. The enrichment completely degraded benzene, toluene, ethylbenzene, and xylenes within 1 to 2 weeks. Also, [14C]benzene was converted to 14CO2, suggesting the culture's ability to mineralize benzene. Community structure analysis revealed that Marinobacter spp. were the dominant members of the enrichment.

  9. Requirement of ArcA for redox regulation in Escherichia coli under microaerobic but not anaerobic or aerobic conditions.

    PubMed

    Alexeeva, Svetlana; Hellingwerf, Klaas J; Teixeira de Mattos, M Joost

    2003-01-01

    In Escherichia coli, the two-component regulatory ArcAB system functions as a major control system for the regulation of expression of genes encoding enzymes involved in both aerobic and anaerobic catabolic pathways. Previously, we have described the physiological response of wild-type E. coli to changes in oxygen availability through the complete range from anaerobiosis to full aerobiosis (S. Alexeeva, B. de Kort, G. Sawers, K. J. Hellingwerf, and M. J. Teixeira de Mattos, J. Bacteriol. 182:4934-4940, 2000, and S. Alexeeva, K. J. Hellingwerf, and M. J. Teixeira de Mattos, J. Bacteriol. 184:1402-1406, 2002). Here, we address the question of the contribution of the ArcAB-dependent transcriptional regulation to this response. Wild-type E. coli and a mutant lacking the ArcA regulator were grown in glucose-limited chemostat cultures at controlled levels of oxygen availability ranging from full aerobiosis to complete anaerobiosis. A flux analysis of the distribution of catabolic fluxes over parallel pathways was carried out, and the intracellular redox state (as reflected by the NADH/NAD ratio) was monitored for all steady states. Deletion of ArcA neither significantly altered the in vivo activity of the pyruvate dehydrogenase complex and pyruvate formate lyase nor significantly affected catabolism under fully aerobic and fully anaerobic conditions. In contrast, profound effects of the absence of ArcA were seen under conditions of oxygen-restricted growth: increased respiration, an altered electron flux distribution over the cytochrome o- and d-terminal oxidases, and a significant change in the intracellular redox state were observed. Thus, the ArcA regulator was found to exert major control on flux distribution, and it is concluded that the ArcAB system should be considered a microaerobic redox regulator.

  10. [Effects of aerobic physical conditioning on the profile of plasma lipoproteins in a group of healthy volunteers].

    PubMed

    Ahumada Ayala, M; Cervera, A; Cardoso, G; Sienra, J C; Fernández de la Vega, P; Marin, J; Posadas, C

    1989-01-01

    To evaluate the effects of aerobic physical conditioning on plasma lipoproteins, we studied 26 previously untrained, apparently healthy, non obese volunteers. All participants underwent a treadmill test performed according to the protocol of Bruce with the direct measurement of maximal oxygen consumption (VO2max). A program of aerobic exercise was prescribed for each volunteer at 70% of their corresponding VO2max. At baseline and at the end of weeks 4, 8 and 12 of the exercise program, cholesterol and triglycerides were measured by enzymatic analysis in total plasma and in the lipoprotein fractions separated by preparative ultracentrifugation and precipitation methods. At the end of week 12, the VO2max measurement was repeated. At the end of the protocol, mean VO2max increased from the value of 39.9 observed at baseline to 94.4 ml/kg/min (p less than 0.01). There were no variations in mean body weight, diet or smoking status of the participants during the exercise program. Cholesterol associated with High-density lipoproteins (C-HDL) increased from 42.5 to 46.1 mg/dl (p less than 0.05). This effect was first noticeable at week 8. We didn't observe significant changes in Total Cholesterol nor the Cholesterol fraction associated with Low-density lipoproteins (C-LDL). Total triglycerides decreased at weeks 4 and 8 but returned to near baseline values at week 12. The C-LDL/C-HDL ratio considered as an index of a high coronary risk decreased from 2.32 at baseline to 2.02 (p less than 0.05) at week 12. Thirteen of the twenty six initial volunteers completed the physical conditioning program as planned, the rest were eliminated at different stages of the protocol due to incomplete adherence to their exercise schedules.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Activity and species composition of aerobic methanotrophic communities in tundra soils.

    PubMed

    Vecherskaya, M S; Galchenko, V F; Sokolova, E N; Samarkin, V A

    1993-09-01

    The low-temperature, methane-oxidizing activities and species composition of methanotrophic communities in various tundra bog soils were investigated by radioisotopic and immunofluorescent methods. Methanotrophic bacteria carried out the methane oxidation process through all horizons of seasonally thawed layers down to permafrost. The highest activity of the process has been observed in the water surface layer of overmoistured soils and in water-logged moss covers. Up to 40% of(14)CH4 added was converted into(14)CO2, bacterial biomass, and organic exometabolites. By immunofluoresecent analysis it was demonstrated that the representatives of I+X (Methylomonas, Methylobacter, andMethylococcus) and II (Methylosinus, Methylocystis) methanotrophic groups occurred simultaneously in all samples at 61.6% and 38.4%, respectively. The number of methane-oxidizing bacteria in the ecosystems studied was 0.1-22.9×10(6) cells per gram of soil. Methanotrophic organisms ranged from 1% to 23% of the total bacterial number. PMID:23835752

  12. Electrokinetic remediation of fluorine-contaminated soil: conditioning of anolyte.

    PubMed

    Kim, Do-Hyung; Jeon, Chil-Sung; Baek, Kitae; Ko, Sung-Hwan; Yang, Jung-Seok

    2009-01-15

    The feasibility of anolyte conditioning on electrokinetic remediation of fluorine-contaminated soil was investigated with a field soil. The initial concentration of fluorine, pH and water content in the soil were 414mg/kg, 8.91 and 15%, respectively. Because the extraction of fluorine generally increased with the soil pH, the pH of the anode compartment was controlled by circulating strong alkaline solution to enhance the extraction of fluorine during electrokinetic remediation. The removal of fluorine increased with the concentration of the alkaline solution and applied current density and fluorine removed up to 75.6% within 14 days. Additionally, anolyte conditioning sharply increased the electro-osmotic flow, which enhanced the removal of fluorine in this study. In many respects, anolyte conditioning in electrokinetic remediation of fluorine-contaminated soil will be a promising technology.

  13. TBA biodegradation in surface-water sediments under aerobic and anaerobic conditions

    USGS Publications Warehouse

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    2002-01-01

    The potential for [U-14C] TBA biodegradation was examined in laboratory microcosms under a range of terminal electron accepting conditions. TBA mineralization to CO2 was substantial in surface-water sediments under oxic, denitrifying, or Mn(IV)-reducing conditions and statistically significant but low under SO4-reducing conditions. Thus, anaerobic TBA biodegradation may be a significant natural attenuation mechanism for TBA in the environment, and stimulation of in situ TBA bioremediation by addition of suitable terminal electron acceptors may be feasible. No degradation of [U-14C] TBA was observed under methanogenic or Fe(III)-reducing conditions.

  14. Butachlor degradation in tropical soils: effect of application rate, biotic-abiotic interactions and soil conditions.

    PubMed

    Pal, R; Das, P; Chakrabarti, K; Chakraborty, A; Chowdhury, A

    2006-01-01

    The degradative characteristics of butachlor (N-Butoxymethyl-2-chloro-2',6'-diethyla- cetanilide) were studied under controlled laboratory conditions in clay loam alluvial (AL) soil (Typic udifluvent) and coastal saline (CS) soil (Typic endoaquept) from rice cultivated fields. The application rates included field rate (FR), 2-times FR (2FR) and 10-times FR (10FR). The incubation study was carried out at 30 degrees C with and without decomposed cow manure (DCM) at 60% of maximum water holding capacity (WHC) and waterlogged soil condition. The half-life values depended on the soil types and initial concentrations of butachlor. Butachlor degraded faster in AL soil and in soil amended with DCM under waterlogged condition. Microbial degradation is the major avenue of butachlor degradation from soils.

  15. Characteristics of the soil-like substrates produced with a novel technique combining aerobic fermentation and earthworm treatment

    NASA Astrophysics Data System (ADS)

    Kang, Wenli; He, Wenting; Li, Leyuan; Liu, Hong

    2012-12-01

    The soil-like substrate (SLS) technique is key for improving the closure of bioregenerative life support system (BLSS) by recycling the inedible biomass of higher plants. In this study, a novel SLS technique (NSLST) was proposed: aerobic fermentations at 35 °C for 1 day, then 60 °C for 6 days, finally 30 °C for 3 days, followed by earthworm treatment for 70 days. Comparing with the original SLS technique (OSLST), its process cycle was 13 days shorter, and the dry weight loss rate (81.1%) was improved by 24.77%. The cellulose and lignin degradation rates were 96.6% and 94.6%. The concentrations of available N, P and K in mature SLS were respectively 776.1 mg/L, 348.0 mg/L and 7943.0 mg/L. Low CH4 and NH3 production was observed, but no accumulation. According to the seed germination test, the SLSs were feasible for plant growth. This investigation will provide a preliminary foundation for BLSS design.

  16. Humitalea rosea gen. nov., sp. nov., an aerobic bacteriochlorophyll-containing bacterium of the family Acetobacteraceae isolated from soil.

    PubMed

    Margesin, Rosa; Zhang, De-Chao

    2013-04-01

    A Gram-staining-negative, pale-pink-pigmented, non-motile, obligately aerobic and rod-shaped bacterium, designated strain W37(T), was isolated from soil and subjected to a taxonomic investigation using a polyphasic approach. The strain grew at 1-30 °C, oxidized thiosulfate and accumulated polyhydroxyalkanoates. Photosynthetic pigments were represented by bacteriochlorophyll a and carotenoids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain W37(T) was most closely related to members of the genera Roseococcus and Rubritepida (with sequence similarities of <92.8 %) but formed a distinct lineage in the family Acetobacteraceae. The polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, three unidentified aminolipids and one other unidentified lipid. The predominant cellular fatty acids were C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain W37(T) was 68.2 mol%. On the basis of phenotypic characteristics and phylogenetic analysis, strain W37(T) represents a novel species of a new genus in the family Acetobacteraceae, for which the name Humitalea rosea gen. nov., sp. nov. is proposed. The type strain of the type species is W37(T) ( = CIP 110261(T) = LMG 26243(T)).

  17. Intracellular Accumulation of Glycine in Polyphosphate-Accumulating Organisms in Activated Sludge, a Novel Storage Mechanism under Dynamic Anaerobic-Aerobic Conditions

    PubMed Central

    Nguyen, Hien Thi Thu; Kristiansen, Rikke; Vestergaard, Mette; Wimmer, Reinhard

    2015-01-01

    Dynamic anaerobic-aerobic feast-famine conditions are applied to wastewater treatment plants to select polyphosphate-accumulating organisms to carry out enhanced biological phosphorus removal. Acetate is a well-known substrate to stimulate this process, and here we show that different amino acids also are suitable substrates, with glycine as the most promising. 13C-labeled glycine and nuclear magnetic resonance (NMR) were applied to investigate uptake and potential storage products when activated sludge was fed with glycine under anaerobic conditions. Glycine was consumed by the biomass, and the majority was stored intracellularly as free glycine and fermentation products. Subsequently, in the aerobic phase without addition of external substrate, the stored glycine was consumed. The uptake of glycine and oxidation of intracellular metabolites took place along with a release and uptake of orthophosphate, respectively. Fluorescence in situ hybridization combined with microautoradiography using 3H-labeled glycine revealed uncultured actinobacterial Tetrasphaera as a dominant glycine consumer. Experiments with Tetrasphaera elongata as representative of uncultured Tetrasphaera showed that under anaerobic conditions it was able to take up labeled glycine and accumulate this and other labeled metabolites to an intracellular concentration of approximately 4 mM. All components were consumed under subsequent aerobic conditions. Intracellular accumulation of amino acids seems to be a novel storage strategy for polyphosphate-accumulating bacteria under dynamic anaerobic-aerobic feast-famine conditions. PMID:25956769

  18. Intracellular Accumulation of Glycine in Polyphosphate-Accumulating Organisms in Activated Sludge, a Novel Storage Mechanism under Dynamic Anaerobic-Aerobic Conditions.

    PubMed

    Nguyen, Hien Thi Thu; Kristiansen, Rikke; Vestergaard, Mette; Wimmer, Reinhard; Nielsen, Per Halkjær

    2015-07-01

    Dynamic anaerobic-aerobic feast-famine conditions are applied to wastewater treatment plants to select polyphosphate-accumulating organisms to carry out enhanced biological phosphorus removal. Acetate is a well-known substrate to stimulate this process, and here we show that different amino acids also are suitable substrates, with glycine as the most promising. (13)C-labeled glycine and nuclear magnetic resonance (NMR) were applied to investigate uptake and potential storage products when activated sludge was fed with glycine under anaerobic conditions. Glycine was consumed by the biomass, and the majority was stored intracellularly as free glycine and fermentation products. Subsequently, in the aerobic phase without addition of external substrate, the stored glycine was consumed. The uptake of glycine and oxidation of intracellular metabolites took place along with a release and uptake of orthophosphate, respectively. Fluorescence in situ hybridization combined with microautoradiography using (3)H-labeled glycine revealed uncultured actinobacterial Tetrasphaera as a dominant glycine consumer. Experiments with Tetrasphaera elongata as representative of uncultured Tetrasphaera showed that under anaerobic conditions it was able to take up labeled glycine and accumulate this and other labeled metabolites to an intracellular concentration of approximately 4 mM. All components were consumed under subsequent aerobic conditions. Intracellular accumulation of amino acids seems to be a novel storage strategy for polyphosphate-accumulating bacteria under dynamic anaerobic-aerobic feast-famine conditions. PMID:25956769

  19. Biodegradation of malachite green by Pseudomonas sp. strain DY1 under aerobic condition: characteristics, degradation products, enzyme analysis and phytotoxicity.

    PubMed

    Du, Lin-Na; Wang, Sheng; Li, Gang; Wang, Bing; Jia, Xiao-Ming; Zhao, Yu-Hua; Chen, Yun-Long

    2011-03-01

    Malachite green (MG), a widely-used and recalcitrant dye, has been confirmed to be carcinogenic and mutagenic against many organisms. The main objective of this study is to investigate the capability of Pseudomonas sp. strain DY1 to decolorize MG, and to explore the possible mechanism. The results showed that this strain demonstrated high decolorizing capability (90.3-97.2%) at high concentrations of MG (100-1,000 mg/l) under shaking condition within 24 h. In static conditions, lower but still effective decolorization (78.9-84.3%) was achieved. The optimal pH and temperature for the decolorization was pH 6.6 and 28-30°C, respectively. Mg(2+) and Mn(2+) (1 mM) were observed to significantly enhance the decolorization. The intermediates of the MG degradation under aerobic condition identified by UV-visible, GC-MS and LC-MS analysis included malachite green carbinol, (dimethyl amino-phenyl)-phenyl-methanone, N,N-dimethylaniline, (methyl amino-phenyl)-phenyl-methanone, (amino phenyl)-phenyl methanone and di-benzyl methane. The enzyme analysis indicated that Mn-peroxidase, NADH-DCIP and MG reductase were involved in the biodegradation of MG. Moreover, phytotoxicity of MG and detoxification for MG by the strain were observed. Therefore, this strain could be potentially used for bioremediation of MG.

  20. Higher Water Temperature and Incubation under Aerobic and Microaerobic Conditions Increase the Recovery and Diversity of Arcobacter spp. from Shellfish

    PubMed Central

    Levican, Arturo; Collado, Luis; Yustes, Clara; Aguilar, Carme

    2014-01-01

    Some Arcobacter species are considered emerging food-borne and waterborne pathogens, and shellfish have been suggested as one of their reservoirs. However, only a few studies have investigated the presence of Arcobacter in this kind of food. This study assesses the prevalence and diversity of Arcobacter spp. in shellfish by multiplex PCR (m-PCR) and culturing methods (under different atmospheric conditions) and evaluates the possible influence of environmental parameters (temperature, salinity, and harvesting bay). Arcobacter was detected by m-PCR and/or culturing in 61 (29.9%) of 204 shellfish samples. Of the positive samples by culturing, 41.1% were obtained under only aerobic incubation conditions, while 23.2% were obtained under only microaerobic conditions. Of 476 investigated isolates, 118 belonged to different enterobacterial repetitive intergenic consensus (ERIC)-PCR genotypes (strains) and to 11 different species. This study shows the highest diversity of Arcobacter species ever observed in samples from any origin. The most prevalent species was Arcobacter butzleri (60.2%), followed by Arcobacter molluscorum (21.2%). The prevalence of Arcobacter was significantly higher during the summer than in other seasons, being associated with an increase in water temperature. Results confirm that shellfish are a reservoir for a remarkable diversity of Arcobacter spp. PMID:24185851

  1. Influence of climatic conditions and soil type on 99TcO4- uptake by rye grass.

    PubMed

    Echevarria, Guillaume; Morel, Jean Louis; Florentin, Louis; Leclerc-Cessac, Elisabeth

    2003-01-01

    Climatic changes over the long term will modify significantly the biosphere, with glaciation events probably taking place in the next 100 000 years. This is important to safety assessments of nuclear waste disposal facilities that contain high-level and long-lived waste. The soils will evolve toward new situations, and their properties will be consequently modified (e.g. an increase of soil organic matter may be expected in a cooler climate). These changes in soil properties would affect the mobility and the soil-to-plant transfer of radionuclides such as (99)Tc. This study aimed at simulating the cooling of climatic conditions for soils representative of a Jurassic limestone plateau, and the effect on transfer parameters of (99)TcO(4)(-) in the soil-plant systems was investigated. The cooler conditions were simulated by increasing elevation, a surrogate for climate change. Soils were sampled in similar geological background and topography at different elevations in the north east of France (Lorraine and Jura). Soil/solution distribution coefficients (K(d)) of (99)TcO(4)(-) were measured on soil samples in short-term batch experiments with 1:10 soil:solution ratio. Rye grass was grown on the soils spiked with (99)TcO(4)(-) at temperature regimes adapted to each soil. Also, two different temperature regimes (cold and temperate) were applied to one soil to test the effect of plant physiology and evapotranspiration on (99)TcO(4)(-) uptake. K(d) values did not show significant differences among soils in aerobic conditions, and were not significantly different from 0. During plant culture, reduction of (99)Tc was never totally achieved in soils, including in a peaty OM soil. Concentration ratios (CR) were calculated on a dry weight basis and ranged from 20 to 370. CR were always higher in high temperature regimes than in cold temperatures. They were also inversely correlated with soil organic matter (OM) content. A decrease of CR values from 5 to 10-fold was observed

  2. Volatile chemical spoilage indexes of raw Atlantic salmon (salmo salar)stored under aerobic condition in relation to microbiological and sensory shelf lives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this investigation was to identify and quantify the volatile chemical spoilage indexes (CSIs) for raw Atlantic salmon (Salmo salar) fillets stored under aerobic storage conditions at 4, 10 and 21 degrees C in relation to the determined microbial and sensory shelf lives. The volatile o...

  3. Model based evaluation of a contaminant plume development under aerobic and anaerobic conditions in 2D bench-scale tank experiments.

    PubMed

    Ballarini, E; Beyer, C; Bauer, R D; Griebler, C; Bauer, S

    2014-06-01

    The influence of transverse mixing on competitive aerobic and anaerobic biodegradation of a hydrocarbon plume was investigated using a two-dimensional, bench-scale flow-through laboratory tank experiment. In the first part of the experiment aerobic degradation of increasing toluene concentrations was carried out by the aerobic strain Pseudomonas putida F1. Successively, ethylbenzene (injected as a mixture of unlabeled and fully deuterium-labeled isotopologues) substituted toluene; nitrate was added as additional electron acceptor and the anaerobic denitrifying strain Aromatoleum aromaticum EbN1 was inoculated to study competitive degradation under aerobic /anaerobic conditions. The spatial distribution of anaerobic degradation was resolved by measurements of compound-specific stable isotope fractionation induced by the anaerobic strain as well as compound concentrations. A fully transient numerical reactive transport model was employed and calibrated using measurements of electron donors, acceptors and isotope fractionation. The aerobic phases of the experiment were successfully reproduced using a double Monod kinetic growth model and assuming an initial homogeneous distribution of P. putida F1. Investigation of the competitive degradation phase shows that the observed isotopic pattern cannot be explained by transverse mixing driven biodegradation only, but also depends on the inoculation process of the anaerobic strain. Transient concentrations of electron acceptors and donors are well reproduced by the model, showing its ability to simulate transient competitive biodegradation. PMID:24122285

  4. Rhythm of carbon and nitrogen fixation in unicellular cyanobacteria under turbulent and highly aerobic conditions.

    PubMed

    Krishnakumar, S; Gaudana, Sandeep B; Viswanathan, Ganesh A; Pakrasi, Himadri B; Wangikar, Pramod P

    2013-09-01

    Nitrogen fixing cyanobacteria are being increasingly explored for nitrogenase-dependent hydrogen production. Commercial success however will depend on the ability to grow these cultures at high cell densities. Photo-limitation at high cell densities leads to hindered photoautotrophic growth while turbulent conditions, which simulate flashing light effect, can lead to oxygen toxicity to the nitrogenase enzyme. Cyanothece sp. strain ATCC 51142, a known hydrogen producer, is reported to grow and fix nitrogen under moderately oxic conditions in shake flasks. In this study, we explore the growth and nitrogen fixing potential of this organism under turbulent conditions with volumetric oxygen mass transfer coefficient (KL a) values that are up to 20-times greater than in shake flasks. In a stirred vessel, the organism grows well in turbulent regime possibly due to a simulated flashing light effect with optimal growth at Reynolds number of approximately 35,000. A respiratory burst lasting for about 4 h creates anoxic conditions intracellularly with near saturating levels of dissolved oxygen in the extracellular medium. This is concomitant with complete exhaustion of intracellular glycogen storage and upregulation of nifH and nifX, the genes encoding proteins of the nitrogenase complex. Further, the rhythmic oscillations in exhaust gas CO2 and O2 profiles synchronize faithfully with those in biochemical parameters and gene expression thereby serving as an effective online monitoring tool. These results will have important implications in potential commercial success of nitrogenase-dependent hydrogen production by cyanobacteria.

  5. Simultaneous phosphorus uptake and denitrification by EBPR-r biofilm under aerobic conditions: effect of dissolved oxygen.

    PubMed

    Wong, Pan Yu; Ginige, Maneesha P; Kaksonen, Anna H; Cord-Ruwisch, Ralf; Sutton, David C; Cheng, Ka Yu

    2015-01-01

    A biofilm process, termed enhanced biological phosphorus removal and recovery (EBPR-r), was recently developed as a post-denitrification approach to facilitate phosphorus (P) recovery from wastewater. Although simultaneous P uptake and denitrification was achieved despite substantial intrusion of dissolved oxygen (DO >6 mg/L), to what extent DO affects the process was unclear. Hence, in this study a series of batch experiments was conducted to assess the activity of the biofilm under various DO concentrations. The biofilm was first allowed to store acetate (as internal storage) under anaerobic conditions, and was then subjected to various conditions for P uptake (DO: 0-8 mg/L; nitrate: 10 mg-N/L; phosphate: 8 mg-P/L). The results suggest that even at a saturating DO concentration (8 mg/L), the biofilm could take up P and denitrify efficiently (0.70 mmol e(-)/g total solids*h). However, such aerobic denitrification activity was reduced when the biofilm structure was physically disturbed, suggesting that this phenomenon was a consequence of the presence of oxygen gradient across the biofilm. We conclude that when a biofilm system is used, EBPR-r can be effectively operated as a post-denitrification process, even when oxygen intrusion occurs. PMID:26398030

  6. Conditional independence mapping of DIGE data reveals PDIA3 protein species as key nodes associated with muscle aerobic capacity

    PubMed Central

    Burniston, Jatin G.; Kenyani, Jenna; Gray, Donna; Guadagnin, Eleonora; Jarman, Ian H.; Cobley, James N.; Cuthbertson, Daniel J.; Chen, Yi-Wen; Wastling, Jonathan M.; Lisboa, Paulo J.; Koch, Lauren G.; Britton, Steven L.

    2014-01-01

    Profiling of protein species is important because gene polymorphisms, splice variations and post-translational modifications may combine and give rise to multiple protein species that have different effects on cellular function. Two-dimensional gel electrophoresis is one of the most robust methods for differential analysis of protein species, but bioinformatic interrogation is challenging because the consequences of changes in the abundance of individual protein species on cell function are unknown and cannot be predicted. We conducted DIGE of soleus muscle from male and female rats artificially selected as either high- or low-capacity runners (HCR and LCR, respectively). In total 696 protein species were resolved and LC–MS/MS identified proteins in 337 spots. Forty protein species were differentially (P < 0.05, FDR < 10%) expressed between HCR and LCR and conditional independence mapping found distinct networks within these data, which brought insight beyond that achieved by functional annotation. Protein disulphide isomerase A3 emerged as a key node segregating with differences in aerobic capacity and unsupervised bibliometric analysis highlighted further links to signal transducer and activator of transcription 3, which were confirmed by western blotting. Thus, conditional independence mapping is a useful technique for interrogating DIGE data that is capable of highlighting latent features. PMID:24769234

  7. Metabolite analysis of Mycobacterium species under aerobic and hypoxic conditions reveals common metabolic traits.

    PubMed

    Drapal, Margit; Wheeler, Paul R; Fraser, Paul D

    2016-08-01

    A metabolite profiling approach has been implemented to elucidate metabolic adaptation at set culture conditions in five Mycobacterium species (two fast- and three slow-growing) with the potential to act as model organisms for Mycobacterium tuberculosis (Mtb). Analysis has been performed over designated growth phases and under representative environments (nutrient and oxygen depletion) experienced by Mtb during infection. The procedure was useful in determining a range of metabolites (60-120 compounds) covering nucleotides, amino acids, organic acids, saccharides, fatty acids, glycerols, -esters, -phosphates and isoprenoids. Among these classes of compounds, key biomarker metabolites, which can act as indicators of pathway/process activity, were identified. In numerous cases, common metabolite traits were observed for all five species across the experimental conditions (e.g. uracil indicating DNA repair). Amino acid content, especially glutamic acid, highlighted the different properties between the fast- and slow-growing mycobacteria studied (e.g. nitrogen assimilation). The greatest similarities in metabolite composition between fast- and slow-growing mycobacteria were apparent under hypoxic conditions. A comparison to previously reported transcriptomic data revealed a strong correlation between changes in transcription and metabolite content. Collectively, these data validate the changes in the transcription at the metabolite level, suggesting transcription exists as one of the predominant modes of cellular regulation in Mycobacterium. Sectors with restricted correlation between metabolites and transcription (e.g. hypoxic cultivation) warrant further study to elucidate and exploit post-transcriptional modes of regulation. The strong correlation between the laboratory conditions used and data derived from in vivo conditions, indicate that the approach applied is a valuable addition to our understanding of cell regulation in these Mycobacterium species.

  8. Conservation tillage and traffic effects on soil condition

    SciTech Connect

    Raper, R.L.; Reeves, D.W.; Burt, E.C.; Torbert, H.A.

    1994-05-01

    The soil condition resulting from a five-year cotton-wheat double cropping experiment in a sandy loam Coastal Plain soil was investigated using intensive measurements of cone index and dry bulk density. Four tillage treatments including a strip-till (no surface tillage with in-row subsoiling) conservation tillage practice were analyzed. The traffic was controlled in the experimental plots with the USDA-ARS Wide-Frame Tractive Vehicle. Besides the environmental benefits of maintaining the surface residue, the strip-till treatment decreased cone index directly beneath the row, decreased surface bulk density, increased surface moisture content, decreased energy usage, and increased yields. Controlled traffic was beneficial only when in-row subsoiling was not used as an annual tillage treatment. Although differences in soil condition were seen beneath the row middles where traffic occurred, this did not affect the soil condition directly beneath the row. 16 refs., 7 figs., 2 tabs.

  9. Biological sulfide removal under alkaline and aerobic conditions in a packed recycling reactor.

    PubMed

    González-Sánchez, A; Revah, S

    2009-01-01

    The biological sulfide removal from wastewater caustic streams can be achieved without significant dilution by alkaliphilic microorganisms which usually show lower growth and oxidation rates as compared with acidic and neutral bacteria. To improve volumetric removal rates under alkaline condition (pH 10), an Alkaliphilic Sulfide-oxidizing Bacteria Consortium (ASBC) was studied in a Packed Recycling Reactor (PRR). A commercial Nylon fiber resulted to be a convenient packing support for biofilm development as it has high specific area and similar hydrophobic propertie. The PRR reached a maximum sulfide oxidation rate of 100 mmol L(-1) d(-1) with efficiency close to 100%, representing an enhancement of 56% from the maximum sulfide oxidation rate reached for a free cell continuous culture. Higher sulfide loading rates induced oxygen limiting conditions reducing the biological activity despite the considerable biofilm attached on the nylon fiber.

  10. Biological sulfide removal under alkaline and aerobic conditions in a packed recycling reactor.

    PubMed

    González-Sánchez, A; Revah, S

    2009-01-01

    The biological sulfide removal from wastewater caustic streams can be achieved without significant dilution by alkaliphilic microorganisms which usually show lower growth and oxidation rates as compared with acidic and neutral bacteria. To improve volumetric removal rates under alkaline condition (pH 10), an Alkaliphilic Sulfide-oxidizing Bacteria Consortium (ASBC) was studied in a Packed Recycling Reactor (PRR). A commercial Nylon fiber resulted to be a convenient packing support for biofilm development as it has high specific area and similar hydrophobic propertie. The PRR reached a maximum sulfide oxidation rate of 100 mmol L(-1) d(-1) with efficiency close to 100%, representing an enhancement of 56% from the maximum sulfide oxidation rate reached for a free cell continuous culture. Higher sulfide loading rates induced oxygen limiting conditions reducing the biological activity despite the considerable biofilm attached on the nylon fiber. PMID:19381008

  11. Aerobic biodegradation of 2,4,6-trinitrotoluene (TNT) by Bacillus cereus isolated from contaminated soil.

    PubMed

    Mercimek, H Aysun; Dincer, Sadık; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih

    2013-10-01

    In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site. PMID:23715804

  12. Aerobic biodegradation of 2,4,6-trinitrotoluene (TNT) by Bacillus cereus isolated from contaminated soil.

    PubMed

    Mercimek, H Aysun; Dincer, Sadık; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih

    2013-10-01

    In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site.

  13. [Soil Microbial Respiration Under Different Soil Temperature Conditions and Its Relationship to Soil Dissolved Organic Carbon and Invertase].

    PubMed

    Wu, Jing; Chen, Shu-tao; Hu, Zheng-hua; Zhang, Xu

    2015-04-01

    In order to investigate the soil microbial respiration under different temperature conditions and its relationship to soil dissolved organic carbon ( DOC) and invertase, an indoor incubation experiment was performed. The soil samples used for the experiment were taken from Laoshan, Zijinshan, and Baohuashan. The responses of soil microbial respiration to the increasing temperature were studied. The soil DOC content and invertase activity were also measured at the end of incubation. Results showed that relationships between cumulative microbial respiration of different soils and soil temperature could be explained by exponential functions, which had P values lower than 0.001. The coefficient of temperature sensitivity (Q10 value) varied from 1.762 to 1.895. The Q10 value of cumulative microbial respiration decreased with the increase of soil temperature for all soils. The Q10 value of microbial respiration on 27 days after incubation was close to that of 1 day after incubation, indicating that the temperature sensitivity of recalcitrant organic carbon may be similar to that of labile organic carbon. For all soils, a highly significant ( P = 0.003 ) linear relationship between cumulative soil microbial respiration and soil DOC content could be observed. Soil DOC content could explain 31.6% variances of cumulative soil microbial respiration. For the individual soil and all soils, the relationship between cumulative soil microbial respiration and invertase activity could be explained by a highly significant (P < 0.01) linear regression function, which suggested that invertase was a good indicator of the magnitude of soil microbial respiration.

  14. [Soil Microbial Respiration Under Different Soil Temperature Conditions and Its Relationship to Soil Dissolved Organic Carbon and Invertase].

    PubMed

    Wu, Jing; Chen, Shu-tao; Hu, Zheng-hua; Zhang, Xu

    2015-04-01

    In order to investigate the soil microbial respiration under different temperature conditions and its relationship to soil dissolved organic carbon ( DOC) and invertase, an indoor incubation experiment was performed. The soil samples used for the experiment were taken from Laoshan, Zijinshan, and Baohuashan. The responses of soil microbial respiration to the increasing temperature were studied. The soil DOC content and invertase activity were also measured at the end of incubation. Results showed that relationships between cumulative microbial respiration of different soils and soil temperature could be explained by exponential functions, which had P values lower than 0.001. The coefficient of temperature sensitivity (Q10 value) varied from 1.762 to 1.895. The Q10 value of cumulative microbial respiration decreased with the increase of soil temperature for all soils. The Q10 value of microbial respiration on 27 days after incubation was close to that of 1 day after incubation, indicating that the temperature sensitivity of recalcitrant organic carbon may be similar to that of labile organic carbon. For all soils, a highly significant ( P = 0.003 ) linear relationship between cumulative soil microbial respiration and soil DOC content could be observed. Soil DOC content could explain 31.6% variances of cumulative soil microbial respiration. For the individual soil and all soils, the relationship between cumulative soil microbial respiration and invertase activity could be explained by a highly significant (P < 0.01) linear regression function, which suggested that invertase was a good indicator of the magnitude of soil microbial respiration. PMID:26164932

  15. Coenzyme B12 can be produced by engineered Escherichia coli under both anaerobic and aerobic conditions.

    PubMed

    Ko, Yeounjoo; Ashok, Somasundar; Ainala, Satish Kumar; Sankaranarayanan, Mugesh; Chun, Ah Yeong; Jung, Gyoo Yeol; Park, Sunghoon

    2014-12-01

    Coenzyme B12 (Vitamin B12 ) is one of the most complex biomolecules and an essential cofactor required for the catalytic activity of many enzymes. Pseudomonas denitrificans synthesizes coenzyme B12 in an oxygen-dependent manner using a pathway encoded by more than 25 genes that are located in six different operons. Escherichia coli, a robust and suitable host for metabolic engineering was used to produce coenzyme B12 . These genes were cloned into three compatible plasmids and expressed heterologously in E. coli BL21 (DE3). Real-time PCR, SDS-PAGE analysis and bioassay showed that the recombinant E. coli expressed the coenzyme B12 synthetic genes and successfully produced coenzyme B12 . However, according to the quantitative determination by inductively coupled plasma-mass spectrometry, the amount of coenzyme B12 produced by the recombinant E. coli (0.21 ± 0.02 μg/g cdw) was approximately 13-fold lower than that by P. denitrificans (2.75 ± 0.22 μg/g cdw). Optimization of the culture conditions to improve the production of coenzyme B12 by the recombinant E. coli was successful, and the highest titer (0.65 ± 0.03 μg/g cdw) of coenzyme B12 was obtained. Interestingly, although the synthesis of coenzyme B12 in P. denitrificans is strictly oxygen-dependent, the recombinant E. coli could produce coenzyme B12 under anaerobic conditions.

  16. Response of aerobic rice to Piriformospora indica.

    PubMed

    Das, Joy; Ramesh, K V; Maithri, U; Mutangana, D; Suresh, C K

    2014-03-01

    Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomusfasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P. indica resembling "Mayan temple" was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza. PMID:24669667

  17. Effect of operating conditions in soil aquifer treatment on the removals of pharmaceuticals and personal care products.

    PubMed

    He, Kai; Echigo, Shinya; Itoh, Sadahiko

    2016-09-15

    Soil aquifer treatment (SAT) is an alternative advanced treatment for wastewater reclamation, and it has the potential to control micropollutants including pharmaceuticals and personal care products (PPCPs). However, the relationship of operating conditions in SAT and removals of micropollutants was not clear. In this study, the effects of operating conditions on the removals of PPCPs were evaluated by using lab-scale columns and plant pilot-scale reactors under different operating conditions. Firstly, weathered granite soil (WGS), standard sand (SAND) and Toyoura standard sand (TS) have different soil characteristics such as total organic carbon (TOC) and cation exchange capacity (CEC). In the columns with these packing materials, the removals of carboxylic analgesics and antilipidemics were effective regardless packing materials. The removals of antibiotics were more effective in WGS than in TS and SAND, indicating high TOC and CEC enhance the sorption in SAT. Secondly, with the extension of hydraulic retention time (HRT), the removals of sulfamethoxazole, acetaminophen, crotamiton, and antipyrine were improved in WGS columns, and adaptable biodegradation for moderately removable PPCPs was formed. Thirdly, the removal efficiencies of sulfamethoxazole and crotamiton were higher in the WGS column under vadose condition than in the WGS column under saturated condition, because of aerobic condition in WGS column under vadose condition. Though long HRT and vadose condition had positive influence on the removals of several PPCPs such as sulfamethoxazole, WGS column with an HRT of 7days under saturated condition removed most PPCPs. PMID:27213846

  18. Effect of operating conditions in soil aquifer treatment on the removals of pharmaceuticals and personal care products.

    PubMed

    He, Kai; Echigo, Shinya; Itoh, Sadahiko

    2016-09-15

    Soil aquifer treatment (SAT) is an alternative advanced treatment for wastewater reclamation, and it has the potential to control micropollutants including pharmaceuticals and personal care products (PPCPs). However, the relationship of operating conditions in SAT and removals of micropollutants was not clear. In this study, the effects of operating conditions on the removals of PPCPs were evaluated by using lab-scale columns and plant pilot-scale reactors under different operating conditions. Firstly, weathered granite soil (WGS), standard sand (SAND) and Toyoura standard sand (TS) have different soil characteristics such as total organic carbon (TOC) and cation exchange capacity (CEC). In the columns with these packing materials, the removals of carboxylic analgesics and antilipidemics were effective regardless packing materials. The removals of antibiotics were more effective in WGS than in TS and SAND, indicating high TOC and CEC enhance the sorption in SAT. Secondly, with the extension of hydraulic retention time (HRT), the removals of sulfamethoxazole, acetaminophen, crotamiton, and antipyrine were improved in WGS columns, and adaptable biodegradation for moderately removable PPCPs was formed. Thirdly, the removal efficiencies of sulfamethoxazole and crotamiton were higher in the WGS column under vadose condition than in the WGS column under saturated condition, because of aerobic condition in WGS column under vadose condition. Though long HRT and vadose condition had positive influence on the removals of several PPCPs such as sulfamethoxazole, WGS column with an HRT of 7days under saturated condition removed most PPCPs.

  19. Extension of laboratory-measured soil spectra to field conditions

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Weismiller, R. A.; Biehl, L. L.; Robinson, B. F.

    1982-01-01

    Spectral responses of two glaciated soils, Chalmers silty clay loam and Fincastle silt loam, formed under prairie grass and forest vegetation, respectively, were measured in the laboratory under controlled moisture equilibria using an Exotech Model 20C spectroradiometer to obtain spectral data in the laboratory under artificial illumination. The same spectroradiometer was used outdoors under solar illumination to obtain spectral response from dry and moistened field plots with and without corn residue cover, representing the two different soils. Results indicate that laboratory-measured spectra of moist soil are directly proportional to the spectral response of that same field-measured moist bare soil over the 0.52 micrometer to 1.75 micrometer wavelength range. The magnitudes of difference in spectral response between identically treated Chalmers and Fincastle soils are greatest in the 0.6 micrometers to 0.8 micrometer transition region between the visible and near infrared, regardless of field condition or laboratory preparation studied.

  20. Molecular analysis of the biomass of a fluidized bed reactor treating synthetic vinasse at anaerobic and micro-aerobic conditions.

    PubMed

    Rodríguez, Elisa; Lopes, Alexandre; Fdz-Polanco, María; Stams, Alfons J M; García-Encina, Pedro A

    2012-03-01

    The microbial communities (Bacteria and Archaea) established in an anaerobic fluidized bed reactor used to treat synthetic vinasse (betaine, glucose, acetate, propionate, and butyrate) were characterized by denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis. This study was focused on the competitive and syntrophic interactions between the different microbial groups at varying influent substrate to sulfate ratios of 8, 4, and 2 and anaerobic or micro-aerobic conditions. Acetogens detected along the anaerobic phases at substrate to sulfate ratios of 8 and 4 seemed to be mainly involved in the fermentation of glucose and betaine, but they were substituted by other sugar or betaine degraders after oxygen application. Typical fatty acid degraders that grow in syntrophy with methanogens were not detected during the entire reactor run. Likely, sugar and betaine degraders outnumbered them in the DGGE analysis. The detected sulfate-reducing bacteria (SRB) belonged to the hydrogen-utilizing Desulfovibrio. The introduction of oxygen led to the formation of elemental sulfur (S(0)) and probably other sulfur compounds by sulfide-oxidizing bacteria (γ-Proteobacteria). It is likely that the sulfur intermediates produced from sulfide oxidation were used by SRB and other microorganisms as electron acceptors, as was supported by the detection of the sulfur respiring Wolinella succinogenes. Within the Archaea population, members of Methanomethylovorans and Methanosaeta were detected throughout the entire reactor operation. Hydrogenotrophic methanogens mainly belonging to the genus Methanobacterium were detected at the highest substrate to sulfate ratio but rapidly disappeared by increasing the sulfate concentration. PMID:21861082

  1. Fate of nonylphenol ethoxylate (NPEO) and its inhibitory impact on the biodegradation of acetate under aerobic conditions.

    PubMed

    Ekdal, Alpaslan

    2014-01-01

    This study evaluated the kinetics of nonylphenol ethoxylate (NPEO) and acetate biodegradation at a moderate sludge age by acclimated culture under aerobic conditions. A laboratory-scale sequencing batch reactor was set and fed only with acetate mixture. The system was operated at steady state with a sludge age of 8 days. Following this stage, a mixture of NPEO and acetate was fed to the mixed culture in order to assess the biodegradation kinetics of NPEO and its impact on acetate utilization. A mechanistic model was developed involving model components and kinetic parameters for both substrates. The model was calibrated with parameters such as oxygen uptake rate and polyhydroxyalkanoates. Biodegradation characteristics and kinetics of acetate and NPEO were estimated by using the model results. Evaluation of calibrated model indicated that exposure of NPEO to non-acclimated sludge caused significant inhibitory impact on the utilization and storage of acetate. However, acclimation ofbiomass greatly suppressed inhibitory effects of NPEO on growth process involved in the degradation of acetate.

  2. Laboratory Study of Chemical Speciation of Mercury in Lake Sediment and Water under Aerobic and Anaerobic Conditions

    PubMed Central

    Regnell, Olof; Tunlid, Anders

    1991-01-01

    Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems than in the aerobic systems. The composition and total concentration of fatty acids originating from bacterial phospholipids, as well as the concentration of vitamin B12, including related cobalamins, were similar in sediments from the anaerobic and aerobic systems. Bacterial cell numbers were, on average, 3.6 times higher in the anaerobic water columns than in the aerobic ones. Volatilization of 203Hg occurred in all systems except in an autoclaved control and was of similar magnitudes in the anaerobic and aerobic systems. Incorporation of 203Hg into the sediment was significantly faster in the aerobic systems than in the anaerobic systems. These results suggest that episodes of anoxia in bottom waters and sediment cause an increase in net mercury methylation and, hence, an increase in bioavailable mercury. PMID:16348444

  3. Fate of inoculated Escherichia coli O157:H7, cultured under different conditions, on fresh and decontaminated beef transitioned from vacuum to aerobic packaging.

    PubMed

    Ashton, Laura V; Geornaras, Ifigenia; Stopforth, Jarret D; Skandamis, Panagiotis N; Belk, Keith E; Scanga, John A; Smith, Gary C; Sofos, John N

    2006-06-01

    This study evaluated the behavior of Escherichia coli O157:H7 during aerobic storage, after storage in vacuum packages, on beef inoculated with cultures prepared (35 degrees C, 24 h) in tryptic soy broth without dextrose (TSB), nonacid hot water carcass decontamination runoff fluids (washings; pH 6.0; WASH), cells from biofilms formed on stainless steel coupons in WASH (WETB), or WETB dried (25 degrees C, 12 h) before harvesting of cells (DRYB). These inocula were applied to fresh beef pieces (40 cm2), which were then left untreated or treated by immersion in hot water (75 degrees C) followed by 2% lactic acid (55 degrees C; hot water/lactic acid [HW/LA]), for 30 s each. Inoculated samples were vacuum packaged and stored at 0 (30, 60, or 90 days), 4 (7 or 14 days), or 12 degrees C (4 or 8 days) and subsequently transferred to retail packages for aerobic storage at 7 degrees C for 5 days. Populations of E. coli O157:H117, regardless of inoculum type, remained generally unchanged (P > 0.05) after aerobic storage (7 degrees C, 5 days) of untreated or HW/LA-treated beef samples previously stored in vacuum packages at 0 or 4 degrees C. However, reductions in E. coli O157:H7 levels were generally obtained when vacuum packaged, untreated beef samples previously stored at 12 degrees C were transitioned to aerobic conditions. Additionally, despite similar (P > 0.05) levels of E. coli O157:H7 cells of TSB, WASH, WETB, and DRYB origin on vacuum-packaged, untreated samples after 8 days of storage at 12 degrees C, subsequent aerobic storage resulted in larger (P < 0.05) reductions of cells of WETB and DRYB origin than for cells of TSB and WASH origin. For HW/LA-treated beef previously stored at 12 degrees C in vacuum packages, populations of E. coli O157:H7 remained largely unchanged after aerobic storage in retail packages. Results thus indicated that aerobic storage of beef (7 degees C, 5 days) previously stored in vacuum packages at 0 or 4 degrees C did not lead to E. coli O

  4. Optimization of operation conditions for the startup of aerobic granular sludge reactors biologically removing carbon, nitrogen, and phosphorous.

    PubMed

    Lochmatter, Samuel; Holliger, Christof

    2014-08-01

    The transformation of conventional flocculent sludge to aerobic granular sludge (AGS) biologically removing carbon, nitrogen and phosphorus (COD, N, P) is still a main challenge in startup of AGS sequencing batch reactors (AGS-SBRs). On the one hand a rapid granulation is desired, on the other hand good biological nutrient removal capacities have to be maintained. So far, several operation parameters have been studied separately, which makes it difficult to compare their impacts. We investigated seven operation parameters in parallel by applying a Plackett-Burman experimental design approach with the aim to propose an optimized startup strategy. Five out of the seven tested parameters had a significant impact on the startup duration. The conditions identified to allow a rapid startup of AGS-SBRs with good nutrient removal performances were (i) alternation of high and low dissolved oxygen phases during aeration, (ii) a settling strategy avoiding too high biomass washout during the first weeks of reactor operation, (iii) adaptation of the contaminant load in the early stage of the startup in order to ensure that all soluble COD was consumed before the beginning of the aeration phase, (iv) a temperature of 20 °C, and (v) a neutral pH. Under such conditions, it took less than 30 days to produce granular sludge with high removal performances for COD, N, and P. A control run using this optimized startup strategy produced again AGS with good nutrient removal performances within four weeks and the system was stable during the additional operation period of more than 50 days.

  5. Investigation of oxidative phosphorylation in continuous cultures. A non-equilibrium thermodynamic approach to energy transduction for Escherichia coli in aerobic condition

    NASA Astrophysics Data System (ADS)

    Ghafuri, Mohazabeh; Nosrati, Mohsen; Hosseinkhani, Saman

    2015-03-01

    Adenosine triphosphate (ATP) production in living cells is very important. Different researches have shown that in terms of mathematical modeling, the domain of these investigations is essentially restricted. Recently the thermodynamic models have been suggested for calculation of the efficiency of oxidative phosphorylation process and rate of energy loss in animal cells using chemiosmotic theory and non-equilibrium thermodynamics equations. In our previous work, we developed a mathematical model for mitochondria of animal cells. In this research, according to similarities between oxidative phosphorylation process in microorganisms and animal cells, Golfar's model was developed to predict the non-equilibrium thermodynamic behavior of the oxidative phosphorylation process for bacteria in aerobic condition. With this model the rate of energy loss, P/O ratio, and efficiency of oxidative phosphorylation were calculated for Escherichia coli in aerobic condition. The results then were compared with experimental data given by other authors. The thermodynamic model had an acceptable agreement with the experimental data.

  6. Stability of immobilized 2,4,6-trinitrotoluene metabolites in soil under long-term leaching conditions.

    PubMed

    Achtnich, C; Lenke, H

    2001-02-01

    2,4,6-Trinitrotoluene (TNT)-contaminated soil was remediated by an anaerobic/aerobic slurry process. Prior to treatment, the soil was spiked with [14C]-TNT. Leaching experiments were carried out with the decontaminated soil to determine the degree of binding of the radiolabel under a variety of conditions. To simulate natural degradation processes of soil organic matter, each of three columns was subjected to a different treatment known to enhance biological transformation over a 92-week period. Only minor amounts of radioactivity (1.0% of the bound radioactivity) were released from treated soil incubated in the presence of the lignin-degrading fungus Phanerochaete chrysosporium. Simulation of seasonal variation in temperature, including freezing of the soil, did not cause a significant release of radioactivity (1.4%). Growth and flowering of the bush bean Phaseolus vulgaris only released 0.8% of the bound radioactivity to the eluate; however, during the decomposition phase, an additional 7.7% of the bound radioactivity was released. We propose that this radioactivity was bound to soluble humic material that was mobilized due to a pH shift during the decomposition of the plant organic matter. This is supported by the observation that neither free TNT nor its metabolites were present in the eluate. During the different incubation experiments, 3.9 to 8.5% of the bound radioactivity was found as 14CO2. The results indicate a slow turnover of even strongly bound immobilized metabolites of TNT.

  7. Unification of soil feedback patterns under different evaporation conditions to improve soil differentiation over flat area

    NASA Astrophysics Data System (ADS)

    Guo, Shanxin; Zhu, A.-Xing; Meng, Lingkui; Burt, James E.; Du, Fei; Liu, Jing; Zhang, Guiming

    2016-07-01

    Detailed and accurate information on the spatial variation of soil types and soil properties are critical components of environmental research and hydrological modeling. Early studies introduced a soil feedback pattern as a promising environmental covariate to predict spatial variation over low-relief areas. However, in practice, local evaporation can have a significant influence on these patterns, making them incomparable at different locations. This study aims to solve this problem by examining the concept of transforming the dynamic patterns of soil feedback from the original time-related space to a new evaporation-related space. A study area in northeastern Illinois with large low-relief farmland was selected to examine the effectiveness of this idea. Images from MODIS in Terra for every April-May period over 12 years (2000-2011) were used to extract the soil feedback patterns. Compared to the original time-related space, the results indicate that the patterns in the new evaporation-related space tend to be more stable and more easily captured from multiple rain events regardless of local evaporation conditions. Random samples selected for soil subgroups from the SSURGO soil map show that patterns in the new space reveal a difference between different soil types. And these differences in patterns are closely related to the difference in the soil structure of the surface layer.

  8. Transport and biotransformation of organic carbon and nitrate compounds in unsaturated soil conditions.

    PubMed

    Bunsri, Thidarat; Sivakumar, Muttucumaru; Hagare, Dharmappa

    2008-01-01

    The lack of drinking water was one of the hot environmental issues that focused on the contaminants released from the failure of sanitary systems. Organic carbon and nitrate compounds were concerned since they represented a potential risk to human health and environment. Mathematical modelling was an effective tool for understanding and estimating the fate and transport of contaminants. An organic carbon and nitrate compounds transport model was developed using the mass balance concept. Richards and multiplicative Monod equations supported the estimating of advection-dispersion transport and biodegradation processes, respectively. The numerical solutions were obtained using the MATLAB programme. The model capability was evaluated using pilot scale experimental data. The depth-averaged time series of pressure head and contaminants concentration profiles were measured several times a week during 91 days. Simulations were found to provide reasonable agreement with the observed data. The aerobic biodegradation zone was observed within 15 cm depth of soil column. Even though the column was operated for 91 days, soil microbes were enough to retard these contaminants. This confirmed that the developed model could be applied to simulate the transport of the contaminants under real time boundary conditions. PMID:19092190

  9. Mathematical modeling of electrochemical remediation for soils under galvanostatic conditions.

    PubMed

    Teutli León, M M; Oropeza Guzmán, M T; González, I

    2001-01-01

    This work proposes a mathematical model for the electrochemical remediation of clayey soils based on the total volume concept for a two-phase system. The mathematical formulation was done including contributions from theories for: groundwater, membranes, porous electrodes and environmental soil chemistry. The resulting model accounts for: free and complexed species in the soil matrix and the pore solution; chemical reactions taking place on either phase and/or between phases; a dynamic soil surface charge affected by the ion content of the pore solution; and electroneutrality of the total volume. Soil surface charge was included in a modified Ohm's law (voltage gradient) and in a modified Schlög's law (convective movement). Numerical implementation was done using orthogonal collocation on finite elements for spatial derivatives, and forward finite differences for time derivatives. Visual Fortran supported by IMSL subroutines was used for computer simulation. Model predictions were successfully compared with reported experimental data. Also, an analysis of pH profiles through the soil is provided for conditions when parameters including hydrostatic head, applied current density and initial pH are modified.

  10. Aerobic granulation utilizing fermented municipal wastewater under low pH and alkalinity conditions in a sequencing batch reactor.

    PubMed

    Leong, Jason; Rezania, Babak; Mavinic, Don S

    2016-01-01

    The aim of this study was to achieve aerobic granulation utilizing fermented municipal wastewater under low pH, and alkalinity conditions. Stable granulation was achieved after a 166-day start-up period. Due to low influent strength, supplemental carbon addition, in the form of sucrose, was added to the feed storage tank on the 82nd day of start-up to facilitate granulation. This increased the system's organic loading rate from 1.43 ± 0.14 to 2.53 ± 0.18 kg COD/m(3)/d, and reduced the influent pH due to fermentation of the added sucrose. Although granulation was successful, the nutrient removal was limited. Removal rates at an influent pH of 6.23 ± 0.06 were 54.4% ± 8.3% for phosphorus, 21.9% ± 4.1% for ammonium, and 84.0% ± 3.0% for total chemical oxygen demand (COD). During the second phase of experimentation, increased amounts of sucrose were added to the feed, which resulted in increased volatile fatty acid concentrations and pH reduction to 5.62 ± 0.12 due to fermentation. Under further reduced pH conditions, phosphorus, ammonium, and total COD removal were found to be 58.9% ± 4.7%, 37.9% ± 4.7%, and 87.1% ± 0.9%, respectively. Settling volume indexes, SVI10 and SVI30, were found to be 148.8 ± 28.9 mL/g, for the influent pH of 6.23 ± 0.06, and 157.5 ± 40.6 mL/g, for the influent pH of 5.62 ± 0.12. This high SVI is indicative of the formation of lower-density granules in comparison to high-ash-content granules. The absence of denitrification-induced chemical phosphorus precipitation within the granule was likely a contributing factor to the low granule density observed in the system.

  11. Influence of aerobic and anaerobic conditions on survival of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in Luria-Bertani broth, farm-yard manure and slurry.

    PubMed

    Semenov, Alexander V; van Overbeek, Leo; Termorshuizen, Aad J; van Bruggen, Ariena H C

    2011-03-01

    The influence of aerobic and anaerobic conditions on the survival of the enteropathogens Escherichia coli O157:H7 and Salmonella serovar Typhimurium was investigated in microcosms with broth, cattle manure or slurry. These substrates were inoculated with a green fluorescent protein transformed strain of the enteropathogens at 10(7) cells g(-1) dry weight. Survival data was fitted to the Weibull model. The survival curves in aerobic conditions generally showed a concave curvature, while the curvature was convex in anaerobic conditions. The estimated survival times showed that E. coli O157:H7 survived significantly longer under anaerobic than under aerobic conditions. Survival ranged from approximately. 2 weeks for aerobic manure and slurry to more than six months for anaerobic manure at 16 °C. On average, in 56.3% of the samplings, the number of recovered E. coli O157:H7 cells by anaerobic incubation of Petri plates was significantly (p < 0.05) higher in comparison with aerobic incubation. Survival of Salmonella serovar Typhimurium was not different between aerobic and anaerobic storage of LB broth or manure as well as between aerobic and anaerobic incubation of Petri dishes. The importance of changes in microbial community and chemical composition of manure and slurry was distinguished for the survival of E. coli O157:H7 in different oxygen conditions.

  12. Biodegradation of a Light NAPL under Varying Soil Environmental Conditions

    NASA Astrophysics Data System (ADS)

    Yadav, B. K.; Hassanizadeh, S. M.; Kleingeld, P. J.

    2009-12-01

    To see the impact of different soil environmental conditions on LNAPL biodegradation, a series of batch, microcosm, column and 2-D tank experiments under controlled conditions have been planned. Microcosms along with batch experiments have been designed for five different moisture contents ranging from residual to saturated, and under varying temperature condition. The batches are being used for two saturated soils containing toluene. For the unsaturated cases, fifteen microcosms are designed to mimic natural conditions more closely. The microcosms consist of a transparent outer column and an air permeable, but watertight, inner tube comprised of toluene phobic material. The space between the outer column and the inner porous tube is filled with a soil having a particular moisture content with a known amount of toluene. The inner porous tube is filled with air at atmospheric pressure, providing sufficient oxygen for the degradation of considered light NAPL. A special sampling mechanism has been fabricated to enable airtight soil sampling. Four columns have been designed for studying the impact of water table fluctuation on the LNAPL fate and transport in variably-saturated soil. Water table in two columns will be static and remaining two will be subjected to a fluctuation. Finally a 2-D tank setup, made of a steel box and a glass cover, has been refurbished for bioremediation process of LNAPL from start to finish. The main body is constructed of one piece of 1.5 mm thick stainless steel formed into a box with inner dimensions of 200cm-long x 94cm-high x 4cm-deep. The front cover is made of glass wall having 19-mm thickness. The soil is going to be packed between the two walls. The groundwater will be flowing horizontally from left to right and the water table level in the tank will be controlled by two end chambers. The chambers are separated from the soil by a fine meshed stainless steel sheet. The spatial and the temporal distributions of the LNAPL and its

  13. Temperature sensitivity of extracellular enzyme kinetics in subtropical wetland soils under different nutrient and water level conditions

    NASA Astrophysics Data System (ADS)

    Goswami, S.; Inglett, K.; Inglett, P.

    2012-12-01

    Microbial extracellular enzymes play an important role in the initial steps of soil organic matter decomposition and are involved in regulating nutrient cycle processes. Moreover, with the recent concern of climate change, microbial extracellular enzymes may affect the functioning (C losses, C sequestration, greenhouse gas emissions, vegetation changes) of different ecosystems. Hence, it is imperative to understand the biogeochemical processes that may be climate change sensitive. Here, we have measured the Michaelis Menten Kinetics [maximal rate of velocity (Vmax) and half-saturation constant (Km)] of 6 enzymes involved in soil organic matter decomposition (phosphatase, phosphodiesterase, β-D-glucosidase, cellobiohydrolase, leucine aminopeptidase, N-Acetyl-β-D glucosaminidase) in different nutrient(P) concentration both aerobically and anaerobically in Everglade water conservation area 2A (F1, F4-slough and U3-slough). Temperature sensitivity of different enzymes is assessed within soil of different P concentrations. We hypothesized that the temperature sensitivity of the enzyme changes with the biogeochemical conditions including water level and nutrient condition. Furthermore, we have tested specific hypothesis that higher P concentration will initiate more C demand for microbes leading to higher Vmax value for carbon processing enzymes in high P site. We found temperature sensitivity of all enzymes for Vmax and Km under both aerobic and anaerobic condition ranges from 0.6 to 3.2 for Vmax and 0.5 to 2.5 for Km. Q10 values of Km for glucosidase indicate more temperature sensitivity under anaerobic condition. Under aerobic condition higher temperature showed significant effect on Vmax for bisphosphatase between high P and low P site. Decreasing P concentration from F1 site to U3-S site had showed significant effect in all temperature on carbon processing enzyme. This suggests that in high P site, microbes will use more carbon-processing enzyme to get more carbon

  14. Soil Properties, Nutrient Dynamics, and Soil Enzyme Activities Associated with Garlic Stalk Decomposition under Various Conditions

    PubMed Central

    Han, Xu; Cheng, Zhihui; Meng, Huanwen

    2012-01-01

    The garlic stalk is a byproduct of garlic production and normally abandoned or burned, both of which cause environmental pollution. It is therefore appropriate to determine the conditions of efficient decomposition, and equally appropriate to determine the impact of this decomposition on soil properties. In this study, the soil properties, enzyme activities and nutrient dynamics associated with the decomposition of garlic stalk at different temperatures, concentrations and durations were investigated. Stalk decomposition significantly increased the values of soil pH and electrical conductivity. In addition, total nitrogen and organic carbon concentration were significantly increased by decomposing stalks at 40°C, with a 5∶100 ratio and for 10 or 60 days. The highest activities of sucrase, urease and alkaline phosphatase in soil were detected when stalk decomposition was performed at the lowest temperature (10°C), highest concentration (5∶100), and shortest duration (10 or 20 days). The evidence presented here suggests that garlic stalk decomposition improves the quality of soil by altering the value of soil pH and electrical conductivity and by changing nutrient dynamics and soil enzyme activity, compared to the soil decomposition without garlic stalks. PMID:23226411

  15. Soil microbial respiration from various microhabitats in Arctic landscape: impact of soil type, environmental conditions and soil age

    NASA Astrophysics Data System (ADS)

    Biasi, Christina; Jokinen, Simo; Marushchak, Maija; Trubnikova, Tatiana; Hämäläinen, Kai; Oinonen, Markku; Martikainen, Pertti

    2014-05-01

    methods applied. It seems that the lower decomposability of peat is largely outweighed by higher C stocks at field conditions. Surprisingly, the bare surfaces (peat circles) with 3500 years old C at the surface exhibited about the largest soil microbial respiration rates among all sites as shown by both methods. This is likely due to the immature status of the peat which was during the bulk of its developmental time protected by permafrost, together with high C-densities. The observation is particularly relevant for decomposition of deeper peat at the permafrost-active layer interface in the large vegetated peat plateaus, where soil material similar to the bare surfaces can be found. The results suggest that the chemical nature and high age of the soil SOC in deep peat does not solely guarantee for resistance to decay. Thus, the study highlights risks for potential re-mobilization of C in deep peat soils following thawing. Soil microbial respiration rates need to be better known when predicting the overall carbon sink/source character of tundra ecosystems in a warming climate. Biasi C., Jokinen S., Marushchak M., Hämäläinen K., Trubnikova T., Oinonen M., Martikainen P. (2013). Microbial respiration in Arctic upland and peat soils as source of CO2. Ecosystems. DOI: 10.1007/s10021-013-9710-z.

  16. Soil moisture under contrasted atmospheric conditions in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, César; Cerdà, Artemi; Vicente-Serrano, Sergio M.

    2014-05-01

    , Intraannual changes, Atmospheric parameters, Eastern Spain Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE FP7 project 603498 supported this research. References: Azorin-Molina, C., Connell, B.H., Baena-Calatrava, R. 2009. Sea-breeze convergence zones from AVHRR over the Iberian Mediterranean Area and the Isle of Mallorca, Spain. Journal of Applied Meteorology and Climatology 48 (10), 2069-2085. Azorin-Molina, C., Vicente-Serrano, S. M., Cerdà, A. 2013. Soil moisture changes in two experimental sites in Eastern Spain. Irrigation versus rainfed orchards under organic farming. EGU, Geophysical Research Abstracts, EGU2013-13286. Bodí, M.B., Mataix-Solera, J., Doerr, S.H. & Cerdà, A. 2011. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. 10.1016/j.geoderma.2010.11.009 Cerdà, A. 1995. Soil moisture regime under simulated rainfall in a three years abandoned field in Southeast Spain. Physics and Chemistry of The Earth, 20 (3-4), 271-279. Cerdà, A. 1999. Seasonal and spatial variations in infiltration rates in badland surfaces under Mediterranean climatic conditions. Water Resources Research, 35 (1) 319-328. Cerdà, A. 2002. The effect of season and parent material on water erosion on highly eroded soils in eastern Spain. Journal of Arid Environments, 52, 319-337. García-Fayos, P. García-Ventoso, B. Cerdà, A. 2000. Limitations to Plant establishment on eroded slopes in Southeastern Spain. Journal of Vegetation Science, 11- 77- 86. Ghafoor, A., Murtaza, G., Rehman, M. Z., Saifullah Sabir, M. 2012. Reclamation and salt leaching efficiency for tile drained saline-sodic soil using marginal quality water for irrigating rice and wheat crops. Land Degradation & Development, 23: 1 -9. DOI 10.1002/ldr.1033 Johnston, C. R., Vance, G. F., Ganjegunte, G. K. 2013. Soil properties changes following irrigation with coalbed natural

  17. Carbon black retention in saturated natural soils: Effects of flow conditions, soil surface roughness and soil organic matter.

    PubMed

    Lohwacharin, J; Takizawa, S; Punyapalakul, P

    2015-10-01

    We evaluated factors affecting the transport, retention, and re-entrainment of carbon black nanoparticles (nCBs) in two saturated natural soils under different flow conditions and input concentrations using the two-site transport model and Kelvin probe force microscopy (KPFM). Soil organic matter (SOM) was found to create unfavorable conditions for the retention. Despite an increased flow velocity, the relative stability of the estimated maximum retention capacity in soils may suggest that flow-induced shear stress forces were insufficient to detach nCB. The KPFM observation revealed that nCBs were retained at the grain boundary and on surface roughness, which brought about substantial discrepancy between theoretically-derived attachment efficiency factors and the ones obtained by the experiments using the two-site transport model. Thus, decreasing ionic strength and increasing solution pH caused re-entrainment of only a small fraction of retained nCB in the soil columns.

  18. Aerobic biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) monomers in soils.

    PubMed

    Dasu, Kavitha; Lee, Linda S

    2016-02-01

    Aerobic soil biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) (FTU) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) (HMU) in a forest soil and FTU in an agricultural silty clay loam soil was monitored for up to 6 months. Fluorotelomer alcohols were measured in headspace and parent monomers and all metabolites in soil extracts. Negligible degradation of FTU biodegradation occurred in the agricultural soil with 94 ± 15% recovered at day 180. However, in the forest soil, both FTU and HMU degradation was evident with significant losses of 24% (117 d) and 27% (180 day), respectively, and concomitant increases in the terminal metabolite, perfluorooctanoic acid (PFOA) concentrations were well above what could result from residual 8:2 FTOH. Kinetic modeling estimated half-lives for FTU (aromatic backbone) and HMU (aliphatic backbone) in the forest soil to be 3-5 months and 15.9-22.2 months, respectively. The addition of a structurally similar non-fluorinated FTU analog, toluene-2,4-dicarbamic acid diethyl ester (TDAEE) enhanced production of terminal end products from 8:2 FTOH degradation. However, there was no clear evidence that TDAEE enhanced cleavage of the urethane bond, thus TDAEE appeared to just serve as an additional carbon source. TDAEE's half-life was ∼ one week. A second addition of TDAEE appeared to retard subsequent degradation of FTU exemplifying the microbial dynamics and diversity impacting degradation of polyfluoroalkyl substances. Enhanced degradation of HMU was observed upon re-aeration indicating oxygen may have been limiting during some periods although degradation of intermediate metabolites to terminal metabolites was still occurring, albeit at slower rates.

  19. Aerobic biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) monomers in soils.

    PubMed

    Dasu, Kavitha; Lee, Linda S

    2016-02-01

    Aerobic soil biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) (FTU) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) (HMU) in a forest soil and FTU in an agricultural silty clay loam soil was monitored for up to 6 months. Fluorotelomer alcohols were measured in headspace and parent monomers and all metabolites in soil extracts. Negligible degradation of FTU biodegradation occurred in the agricultural soil with 94 ± 15% recovered at day 180. However, in the forest soil, both FTU and HMU degradation was evident with significant losses of 24% (117 d) and 27% (180 day), respectively, and concomitant increases in the terminal metabolite, perfluorooctanoic acid (PFOA) concentrations were well above what could result from residual 8:2 FTOH. Kinetic modeling estimated half-lives for FTU (aromatic backbone) and HMU (aliphatic backbone) in the forest soil to be 3-5 months and 15.9-22.2 months, respectively. The addition of a structurally similar non-fluorinated FTU analog, toluene-2,4-dicarbamic acid diethyl ester (TDAEE) enhanced production of terminal end products from 8:2 FTOH degradation. However, there was no clear evidence that TDAEE enhanced cleavage of the urethane bond, thus TDAEE appeared to just serve as an additional carbon source. TDAEE's half-life was ∼ one week. A second addition of TDAEE appeared to retard subsequent degradation of FTU exemplifying the microbial dynamics and diversity impacting degradation of polyfluoroalkyl substances. Enhanced degradation of HMU was observed upon re-aeration indicating oxygen may have been limiting during some periods although degradation of intermediate metabolites to terminal metabolites was still occurring, albeit at slower rates. PMID:26624955

  20. Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth.

    PubMed

    Abreu, Lilian D V; Johnson, Paul C

    2006-04-01

    Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed

  1. Recovery of Nickel and Cobalt from Laterite Tailings by Reductive Dissolution under Aerobic Conditions Using Acidithiobacillus Species.

    PubMed

    Marrero, J; Coto, O; Goldmann, S; Graupner, T; Schippers, A

    2015-06-01

    Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53-57%) and cobalt (55-60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach solution (PLS), facilitating the subsequent metal recovery. In addition, an aerobic acid regeneration stage is proposed. Therefore, AeRD process development can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD. PMID:25923144

  2. Recovery of Nickel and Cobalt from Laterite Tailings by Reductive Dissolution under Aerobic Conditions Using Acidithiobacillus Species.

    PubMed

    Marrero, J; Coto, O; Goldmann, S; Graupner, T; Schippers, A

    2015-06-01

    Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53-57%) and cobalt (55-60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach solution (PLS), facilitating the subsequent metal recovery. In addition, an aerobic acid regeneration stage is proposed. Therefore, AeRD process development can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD.

  3. Evaluation of antibiotic mobility in soil associated with swine-slurry soil amendment under cropping conditions.

    PubMed

    Domínguez, C; Flores, C; Caixach, J; Mita, L; Piña, B; Comas, J; Bayona, J M

    2014-11-01

    Interest in identifying pools of antibacterial-resistance genes has grown over the last decade, with veterinary antibiotics (VAs) receiving particular attention. In this paper, a mesoscale study aimed at evaluating the vertical transport of common VAs-namely, fluoroquinolones, tetracyclines, sulfonamides, and lincosamides in agricultural soil subjected to drip irrigation-was performed under greenhouse conditions. Accordingly, leachates of cropped and uncropped soil, amended with swine-slurry leading to 19-38 μg kg(-1) (dry mass) antibiotics in the soil, were analyzed over the course of the productive cycle of a lettuce (42 days) with three sampling campaigns (N = 24). High lincomycin (LCM) concentrations (30-39 μg L(-1)) were detected in the leachates collected from the swine-slurry-amended soil. The highest LCM mass recovered in the leachates (30.1 ± 1.63 %) was obtained from cropped experimental units. In addition, the LCM leaching constant and its leaching potential as obtained from the first-order model were higher in the leachates from the cropped experimental units. Lower concentrations of sulfadimethoxine were also detected in leachates and in soil. Enrofloxacin and oxytetracycline occurred only in soil, which is consistent with high soil interaction.

  4. The effect of the potential fuel additive isobutanol on benzene, toluene, ethylbenzene, and p-xylene degradation in aerobic soil microcosms.

    PubMed

    Ding, Liang; Cupples, Alison M

    2015-01-01

    Isobutanol is being considered as a fuel additive; however, the effect of this chemical on gasoline degradation (following a spill) has yet to be fully explored. To address this, the current study investigated the effect of isobutanol on benzene, toluene, ethylbenzene and p-xylene (BTEX) degradation in 14 sets of experiments in saturated soils. This involved four hydrocarbons for three soils (12 experiments) and two extra experiments with a lower level of isobutanol (for toluene only). Each soil and hydrocarbon combination involved four abiotic control microcosms and 12 sample microcosms (six with and six without isobutanol). The time for complete degradation of each hydrocarbon varied between treatments. Both toluene and ethylbenzene were rapidly degraded (5-13 days for toluene and 3-13 days for ethylbenzene). In contrast, the time for complete degradation for benzene ranged from 5 to 47 days. The hydrocarbon p-xylene was the most recalcitrant chemical (time for removal ranged from 14 to 86 days) and, in several microcosms, no p-xylene degradation was observed. The effect of isobutanol on hydrocarbon degradation was determined by comparing degradation lag times with and without isobutanol addition. From the 14 treatments, isobutanol only affected degradation lag times in three cases. In two cases (benzene and p-xylene), an enhancement of degradation (reduced lag times) was observed in the presence of isobutanol. In contrast, toluene degradation in one soil was inhibited (increased lag time). These results indicate that co-contamination with isobutanol should not inhibit aerobic BTEX degradation rates.

  5. Soil moisture under contrasted atmospheric conditions in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, César; Cerdà, Artemi; Vicente-Serrano, Sergio M.

    2014-05-01

    , Intraannual changes, Atmospheric parameters, Eastern Spain Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE FP7 project 603498 supported this research. References: Azorin-Molina, C., Connell, B.H., Baena-Calatrava, R. 2009. Sea-breeze convergence zones from AVHRR over the Iberian Mediterranean Area and the Isle of Mallorca, Spain. Journal of Applied Meteorology and Climatology 48 (10), 2069-2085. Azorin-Molina, C., Vicente-Serrano, S. M., Cerdà, A. 2013. Soil moisture changes in two experimental sites in Eastern Spain. Irrigation versus rainfed orchards under organic farming. EGU, Geophysical Research Abstracts, EGU2013-13286. Bodí, M.B., Mataix-Solera, J., Doerr, S.H. & Cerdà, A. 2011. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. 10.1016/j.geoderma.2010.11.009 Cerdà, A. 1995. Soil moisture regime under simulated rainfall in a three years abandoned field in Southeast Spain. Physics and Chemistry of The Earth, 20 (3-4), 271-279. Cerdà, A. 1999. Seasonal and spatial variations in infiltration rates in badland surfaces under Mediterranean climatic conditions. Water Resources Research, 35 (1) 319-328. Cerdà, A. 2002. The effect of season and parent material on water erosion on highly eroded soils in eastern Spain. Journal of Arid Environments, 52, 319-337. García-Fayos, P. García-Ventoso, B. Cerdà, A. 2000. Limitations to Plant establishment on eroded slopes in Southeastern Spain. Journal of Vegetation Science, 11- 77- 86. Ghafoor, A., Murtaza, G., Rehman, M. Z., Saifullah Sabir, M. 2012. Reclamation and salt leaching efficiency for tile drained saline-sodic soil using marginal quality water for irrigating rice and wheat crops. Land Degradation & Development, 23: 1 -9. DOI 10.1002/ldr.1033 Johnston, C. R., Vance, G. F., Ganjegunte, G. K. 2013. Soil properties changes following irrigation with coalbed natural

  6. Experiments using new initial soil moisture conditions and soil map in the Eta model over La Plata Basin

    NASA Astrophysics Data System (ADS)

    Doyle, Moira E.; Tomasella, Javier; Rodriguez, Daniel A.; Chou, Sin Chan

    2013-08-01

    An effort towards a more accurate representation of soil moisture and its impact on the modeling of weather systems is presented. Sensitivity tests of precipitation to soil type and soil moisture changes are carried out using the atmospheric Eta model for the numerical simulation of the development of a mesoscale convective system over northern Argentina. Modified initial soil moisture conditions were obtained from a hydrological balance model developed and running operationally at INPE. A new soil map was elaborated using the available soil profile information from Brazil, Paraguay, Uruguay, and Argentina and depicts 18 different soil types. Results indicate that more accurate initial soil moisture conditions and incorporating a new soil map with hydraulic parameters, more representative of South American soils, improve daily total precipitation forecasts both in quantitative and spatial representations.

  7. Three Gorges Reservoir Area: soil erosion under natural condition vs. soil erosion under current land use

    NASA Astrophysics Data System (ADS)

    Schönbrodt, Sarah; Behrens, Thorsten; Scholten, Thomas

    2010-05-01

    Apparently, the current most prominent human-induced example for large scale environmental impact is the Three Gorges Dam in China. The flooding alongside the Yangtze River, and its tributaries results in a vast loss of settlement and farmland area with productive, fertile valley soils. Due to the associated high land use dynamic on uphill-sites, the soil resources are underlying high land use pressure. Within our study, the soil erosion under natural conditions is compared to the soil erosion under current land use after the impoundment. Both were modeled using the empirical Universal Soil Loss Equation (USLE) which is able to predict long-term annual soil loss with limited data. The database consists of digital terrain data (45 m resolution DEM, erosive slope length based on Monte-Carlo-Aggregation according to Behrens et al. (2008)), field investigations of recent erosion forms, and literature studies. The natural disposition to soil erosion was calculated considering the USLE factors R, S, and K. The soil erosion under current land use was calculated taking into account all USLE factors. The study area is the catchment of the Xiangxi River in the Three Gorges Reservoir area. Within the Xiangxi Catchment (3,200 km²) the highly dynamic backwater area (580 km²), and two micro-scale study sites (Xiangjiaba with 2.8 km², and Quyuan with 88 km²) are considered more detailed as they are directly affected by the river impoundment. Central features of the Xiangxi Catchment are the subtropical monsoon climate, an extremely steep sloping relief (mean slope angle 39°, SD 22.8°) artificially fractured by farmland terraces, and a high soil erodibility (mean K factor 0.37, SD 0.13). On the catchment scale the natural disposition to soil erosion makes up to mean 518.0 t ha-1 a-1. The maximum potential soil loss of 1,730.1 t ha-1 a-1 under natural conditions is reached in the Quyuan site (mean 635.8 t ha-1 a-1) within the backwater area (mean 582.9 t ha-1 a-1). In the

  8. Laboratory investigation of boundary condition impacts on nitrate anion exclusion in an unsaturated soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transient unsaturated horizontal column experiments were conducted with a loam soil, under variable boundary conditions, to obtain added insight on anion exclusion processes that impact nitrate transport in soil. The boundary conditions evaluated were column inlet soil water content, initial soil w...

  9. Effects of permafrost thaw on carbon emissions under aerobic and anaerobic environments in the Great Hing'an Mountains, China.

    PubMed

    Song, Changchun; Wang, Xianwei; Miao, Yuqing; Wang, Jiaoyue; Mao, Rong; Song, Yanyu

    2014-07-15

    The carbon (C) pool of permafrost peatland is very important for the global C cycle. Little is known about how permafrost thaw could influence C emissions in the Great Hing'an Mountains of China. Through aerobic and anaerobic incubation experiments, we studied the effects of permafrost thaw on CH4 and CO2 emissions. The rates of CH4 and CO2 emissions were measured at -10, 0 and 10°C. Although there were still C emissions below 0°C, rates of CH4 and CO2 emissions significantly increased with permafrost thaw under aerobic and anaerobic conditions. The C release under aerobic conditions was greater than under anaerobic conditions, suggesting that permafrost thaw and resulting soil environment change should be important influences on C emissions. However, CH4 stored in permafrost soils could affect accurate estimation of CH4 emissions from microbial degradation. Calculated Q10 values in the permafrost soils were significantly higher than values in active-layer soils under aerobic conditions. Our results highlight that permafrost soils have greater potential decomposability than soils of the active layer, and such carbon decomposition would be more responsive to the aerobic environment.

  10. Bioremediation of carbofuran contaminated soil under saturated condition: soil column study.

    PubMed

    Plangklang, Pensri; Reungsang, Alissara; Suphannafai, Wisarut

    2012-06-01

    Disturbed soil columns, 5.8 cm in diameter and 25 cm in length, were used as a basic model to simulate the movement of carbofuran in rice field soil under saturated conditions. Bioaugmentation using a specific carbofuran degrader, Burkholderia sp. PCL3, in free and immobilized cell forms and biostimulation using rice straw as organic amendment were applied with the aim of enhancing the degradation of carbofuran in soil and to prevent the movement of carbofuran along with the flow through. In the abiotic control and the treatment with only indigenous microorganisms, the mass recovery percentage of carbofuran in the effluent was 52.1 and 22.5%, respectively. The application of bioaugmentation or biostimulation significantly enhanced carbofuran degradation in soil and reduced the movement of carbofuran as indicated by a low mass recovery percentage of carbofuran in the effluent of 14.6-15.5%. A low efficiency of carbofuran removal was obtained from the soil column with bioaugmentation together with biostimulation treatments in which the mass recovery percentage of carbofuran in the effluent was in the range of 22.1-22.6%. Sorption of carbofuran to soil, rice straw and corncob, formation of carbofuran metabolite and colony forming unit (CFU) and pH variation with the time were also investigated during column operation.

  11. Aerobic degradation of a hydrocarbon mixture in natural uncontaminated potting soil by indigenous microorganisms at 20 degrees C and 6 degrees C.

    PubMed

    Eriksson, M; Dalhammar, G; Borg-Karlson, A K

    1999-04-01

    A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C14 to C17) was aerobically degraded without lag phase by a natural uncontaminated potting soil at 20 degrees C and 6 degrees C. Starting concentrations were approximately 46 ppm for the aromatic and 13 ppm for the aliphatic compounds. All aliphatic hydrocarbons were degraded within 5 days at 20 degrees C, to levels below detection (ppb levels) but only down to 10% of initial concentration at 6 degrees C. Naphthalene was degraded within 12 days at 20 degrees C and unaffected at 6 degrees C. At 20 degrees C p-xylene was degraded within 20 days, but no degradation occurred at 6 degrees C. Br-naphthalene was only removed down to 30% of initial concentration at 20 degrees C, with no significant effect at 6 degrees C. The biodegradation was monitored with head space solid-phase microextraction and gas chromatography-mass spectrometry.

  12. The effects of aerobic and anaerobic exercise conditioning on resting metabolic rate and the thermic effect of a meal.

    PubMed

    Schmidt, W D; Hyner, G C; Lyle, R M; Corrigan, D; Bottoms, G; Melby, C L

    1994-12-01

    This study examined resting metabolic rate (RMR) and thermic effect of a meal (TEM) among athletes who had participated in long-term anaerobic or aerobic exercise. Nine collegiate wrestlers were matched for age, weight, and fat-free weight with 9 collegiate swimmers. Preliminary testing included maximal oxygen consumption, maximal anaerobic capacity (MAnC) for both the arms and the legs, and percent body fat. On two separate occasions, RMR and TEM were measured using indirect calorimetry. VO2max was significantly higher in the swimmers while MAnC was significantly higher in the wrestlers for both the arms and the legs. RMR adjusted for fat-free weight was not significantly different between groups. The differences in total and percentage of TEM between the groups were not statistically significant, and there were no differences in baseline thyroid hormones. These data suggest that despite significant differences in VO2max and WAnT values following long-term aerobic and anaerobic exercise training, resting energy expenditure does not differ between these college athletes. PMID:7874150

  13. Survival of a microbial soil community under Martian conditions

    NASA Astrophysics Data System (ADS)

    Hansen, A. A.; Noernberg, P.; Merrison, J.; Lomstein, B. Aa.; Finster, K. W.

    2003-04-01

    Because of the similarities between Earth and Mars early history the hypothesis was forwarded that Mars is a site where extraterrestrial life might have and/or may still occur(red). Sample-return missions are planned by NASA and ESA to test this hypothesis. The enormous economic costs and the logistic challenges of these missions make earth-based model facilities inevitable. The Mars simulation system at University of Aarhus, Denmark allows microbiological experiments under Mars analogue conditions. Thus detailed studies on the effect of Mars environmental conditions on the survival and the activity of a natural microbial soil community were carried out. Changes in the soil community were determined with a suite of different approaches: 1) total microbial respiration activity was investigated with 14C-glucose, 2) the physiological profile was investigated by the EcoLog-system, 3) colony forming units were determined by plate counts and 4) the microbial diversity on the molecular level was accessed with Denaturing Gradient Gel Electrophoresis. The simulation experiments showed that a part of the bacterial community survived Martian conditions corresponding to 9 Sol. These and future simulation experiments will contribute to our understanding of the possibility for extraterrestrial and terrestrial life on Mars.

  14. Gas-geochemical condition and ecological functions of urban soils in areas with gas generating grounds

    NASA Astrophysics Data System (ADS)

    Mozharova, Nadezhda; Lebed-Sharlevich, Iana; Kulachkova, Svetlana

    2014-05-01

    important ecological functions of such soils, is initiated. Due to high rate of this process (25-30 ng*g-1*h-1) accumulation of methane in the profile does not observed, its content in soil averages 2-5 ppm. Methane emission from soils is low (0.01-0.03 mg*m-2*h-1) or there is a weak consumption of atmospheric CH4, whereby its concentration in the air corresponds to the average content of this gas. Active methane oxidation and decomposition of organic matter under aerobic conditions result to intensive formation of carbon dioxide and, thus, increase its emission (600 mg*m-2*h-1), concentration in soils (0.2-0.9%) and in atmosphere (up to 0.5%). Fixed concentration of CO2 in the air is dangerous for human health. Thus, presence of gas generating grounds with high content of organic matter leads to methane formation, causing its intensive emission to atmosphere. At upper layers of soils and grounds bacterial oxidation of methane occurs and results in complete CH4 utilization. During this process significant amounts of carbon dioxide are released and accumulated in the atmosphere up to concentration dangerous for people. Carbon dioxide emission increases current level of this gas in the urban atmosphere.

  15. Tools to support maintenance strategies under soft soil conditions

    NASA Astrophysics Data System (ADS)

    Lambert, J. W. M.; van Meerten, J. J.; Woning, M. P.; Eijbersen, M. J.; Huber, M.

    2015-11-01

    Costs for maintenance of infrastructure in municipalities with soft soil underground conditions, are estimated to be almost 40 % higher than in others. As a result, these municipalities meet financial problems that cause overdue maintenance. In some cases municipalities are even afraid to be unable to offer a minimum service level in future. In common, traditional practice, roads and sewerage systems have been constructed in trenches that consist of sandy material that replaces the upper meters of the soft soil. Under influence of its weight, this causes accelerated settlements of the construction. A number of alternative constructions have been developed, e.g. using light-weight materials to limit settlement velocity. In order to limit future maintenance costs, improvement of maintenance strategies is desired. Tools have been and will be developed to support municipalities in improving their maintenance strategies and save money by doing that. A model (BALANS) that weighs the attractiveness of alternative solutions under different soil, environmental and economic circumstances, will be presented.

  16. Phytoremediation of pyrene in a Cecil soil under field conditions.

    PubMed

    Lalande, T L; Skipper, H D; Wolf, D C; Reynolds, C M; Freedman, D L; Pinkerton, B W; Hartel, P G; Grimes, L W

    2003-01-01

    We evaluated the effects of annual ryegrass (Lolium multiflorum Lam.) and phosphorus (P) availability on the dissipation of pyrene added at a concentration of approximately 600 mg kg-1 dry soil in the top 7.5 cm of a Cecil loamy sand (fine, kaolinitic, thermic Typic Kanhapludults) in a 10-month experiment under field conditions in Clemson, South Carolina. Plastic canopies were installed to prevent flooding of plots and raindrop dispersion of pyrene. Treatment factors were pyrene, vegetation, and available P levels. Each of the eight treatments had four replicates. The soil was adjusted to low and high P concentrations (an average of 41 and 66 kg extractable P ha-1, respectively). After a 175-d lag period for all treatments, the rate of pyrene removal followed first-order kinetics. The first-order rate constant was significantly higher in nonvegetated (0.098 d-1) than vegetated treatments (0.034 d-1). These data suggest that the presence of easily biodegradable organic matter from plant roots slowed the removal rate of pyrene. The levels of available P did not affect the rate of pyrene dissipation. Pyrene decreased below the detection limit of 6.25 mg kg-1 dry soil in all treatments after 301 d.

  17. Characterization of Apollo Bulk Soil Samples Under Simulated Lunar Conditions

    NASA Astrophysics Data System (ADS)

    Donaldson Hanna, K. L.; Pieters, C. M.; Thomas, I.; Bowles, N. E.; Greenhagen, B. T.

    2013-12-01

    Remote observations provide key insights into the composition and evolution of planetary surfaces. A fundamentally important component to any remote compositional analysis of planetary surfaces is laboratory measurements of well-characterized samples measured under the appropriate environmental conditions. The vacuum environment of airless bodies like the Moon creates a steep thermal gradient in the upper hundreds of microns of regolith. Lab studies of particulate rocks and minerals as well as selected lunar soils under vacuum and lunar-like conditions have identified significant effects of this thermal gradient on thermal infrared (TIR) spectral measurements [e.g. Logan et al. 1973, Salisbury and Walter 1989, Thomas et al. 2012, Donaldson Hanna et al. 2012]. Such lab studies demonstrate the high sensitivity of TIR emissivity spectra to environmental conditions under which they are measured. To best understand the effects of the near surface-environment of the Moon, a consortium of four institutions with the capabilities of characterizing lunar samples was created. The goal of the Thermal Infrared Emission Studies of Lunar Surface Compositions Consortium (TIRES-LSCC) is to characterize Apollo bulk soil samples with a range of compositions and maturities in simulated lunar conditions to provide better context for the spectral effects due to varying compositions and soil maturity as well as for the interpretation of data obtained by the LRO Diviner Lunar Radiometer and future lunar and airless body thermal emission spectrometers. An initial set of thermal infrared emissivity measurements of the bulk lunar soil samples will be made in three of the laboratories included in the TIRES-LSCC: the Asteroid and Lunar Environment Chamber (ALEC) in RELAB at Brown University, the Simulated Lunar Environment chamber in the Planetary Spectroscopy Facility (PSF) at the University of Oxford, and the Simulated Airless Body Emission Laboratory (SABEL) at the Jet Propulsion Laboratory

  18. Activated sludge mass reduction and biodegradability of the endogenous residues by digestion under different aerobic to anaerobic conditions: Comparison and modeling.

    PubMed

    Martínez-García, C G; Fall, C; Olguín, M T

    2016-03-01

    This study was performed to identify suitable conditions for the in-situ reduction of excess sludge production by intercalated digesters in recycle-activated sludge (RAS) flow. The objective was to compare and model biological sludge mass reduction and the biodegradation of endogenous residues (XP) by digestion under hypoxic, aerobic, anaerobic, and five intermittent-aeration conditions. A mathematical model based on the heterotrophic endogenous decay constant (bH) and including the biodegradation of XP was used to fit the long-term data from the digesters to identify and estimate the parameters. Both the bH constant (0.02-0.05 d(-1)) and the endogenous residue biodegradation constant (bP, 0.001-0.004 d(-1)) were determined across the different mediums. The digesters with intermittent aeration cycles of 12 h-12 h and 5 min-3 h (ON/OFF) were the fastest, compared to the aerobic reactor. The study provides a basis for rating RAS-digester volumes to avoid the accumulation of XP in aeration tanks.

  19. Activated sludge mass reduction and biodegradability of the endogenous residues by digestion under different aerobic to anaerobic conditions: Comparison and modeling.

    PubMed

    Martínez-García, C G; Fall, C; Olguín, M T

    2016-03-01

    This study was performed to identify suitable conditions for the in-situ reduction of excess sludge production by intercalated digesters in recycle-activated sludge (RAS) flow. The objective was to compare and model biological sludge mass reduction and the biodegradation of endogenous residues (XP) by digestion under hypoxic, aerobic, anaerobic, and five intermittent-aeration conditions. A mathematical model based on the heterotrophic endogenous decay constant (bH) and including the biodegradation of XP was used to fit the long-term data from the digesters to identify and estimate the parameters. Both the bH constant (0.02-0.05 d(-1)) and the endogenous residue biodegradation constant (bP, 0.001-0.004 d(-1)) were determined across the different mediums. The digesters with intermittent aeration cycles of 12 h-12 h and 5 min-3 h (ON/OFF) were the fastest, compared to the aerobic reactor. The study provides a basis for rating RAS-digester volumes to avoid the accumulation of XP in aeration tanks. PMID:26720137

  20. Effect of local soil conditions on site amplification

    SciTech Connect

    Chen, J.C.; Bernreuter, D.L.; Johnson, J.J.

    1983-02-18

    The Seismic Safety Margins Research Program (SSMRP) is developing a complete fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. The analysis procedure is based upon a state-of-the-art evaluation of the current seismic analysis and design process and explicitly accounts for uncertainties inherent in such a process. In Phase I, the seismic input, the soil-structure interaction, dynamic response of structures and subsystems, and fragility were developed and combined using a probabilistic computational procedure. Demonstration calculations were completed for the Zion nuclear power plant. In Phase II, presently ongoing, additional models, improvements to existing models, and improvements to the probabilistic computational assessment of Zion have been developed. Local site amplification has significant effect on structural response and is a major source of uncertainty. As part of the final Zion analysis in Phase II, an assessment of the local site effect at the Zion site was made using new time histories modified for the Zion soil conditions. In this paper, we briefly describe the approach used to correct the seismic hazard curve and time histories developed in Phase I for local site effects and discuss in some detail the results of our efforts to validate the approach. The principle step in the approach was the use of an equivalent linear iterative technique assuming vertically incident waves to correct a set of time histories appropriate for a rock outcrop for the local soil column. For the Zion soil column this led to large correction factors.

  1. Pore-scale insights to the rate of organic carbon degradation and biofilm formation under variable hydro-biogeochemical conditions in soils and sediments

    NASA Astrophysics Data System (ADS)

    Liu, C.; Yan, Z.; Liu, Y.; Li, M.; Bailey, V. L.

    2015-12-01

    Biogeochemical processes that control microbial growth, organic carbon degradation, and CO2 production and migration are fundamentally occur at the pore scale. In this presentation, we will describe our recent results of a pore-scale simulation research to investigate: 1) how moisture content and distribution affects oxygen delivery, organic carbon availability, and microbial activities that regulate the rate of organic carbon degradation and CO2 production in aerobic systems; and 2) how pore-scale reactive transport processes affect local microbial growth, biofilm formation, and overall rate of microbial reactions in anoxic systems. The results revealed that there is an optimal moisture content for aerobic bacterial respiration and CO2 production. When moisture is below the optimal value, organic carbon availability limits its degradation due to diffusion and osmotic stress to bacterial reactivity; and when moisture is above the optimal value, oxygen delivery limits microbial respiration. The optimal moisture condition is, however, a function of soil texture and physical heterogeneity, bioavailable soil organic carbon, and microbial community function. In anoxic and saturated system, simulation results show that biofilm preferentially forms in concave areas around sand particles and macro aggregates where cross-directional fluxes of organic carbon and electron acceptors (e.g., nitrate) favor microbial growth and attachment. The results provide important insights to the establishment of constitutive relationships between the macroscopic rates of soil organic carbon degradation and moisture content, and to the development of biogeochemical reactive transport models that incorporate biofilm structures and physio-chemical heterogeneity in soils and sediments.

  2. Soil organic carbon of European forest soils: current stock and projections under climate change conditions

    NASA Astrophysics Data System (ADS)

    Caddeo, Antonio; Marras, Serena; Spano, Donatella; Sirca, Costantino

    2016-04-01

    Soil organic carbon (SOC) represents the largest terrestrial carbon pool, and it is subjected to climate change impacts. In Europe, a limited number of studies makes a wide-scale comparison of SOC stock and changes under climate change conditions, and most of them are related to agricultural soils. In this work, the SOC stock of the forested areas of Europe (obtained from the CORINE 2006 Land Use Map) was assessed at 1 km resolution using the agro-ecosystem SOC model CENTURY. The results of the model were compared with independent observational datasets (i.e. LUCAS Topsoil Survey Database). In addition, climate simulations (RCPs 4.5 and 8.5) using the CMCC (Euro-Mediterranean Centre on Climate Change) and the CORDEX dataset were used to estimate the SOC changes of these areas under climate change conditions.

  3. Biodegradation potential of MTBE in a fractured chalk aquifer under aerobic conditions in long-term uncontaminated and contaminated aquifer microcosms.

    PubMed

    Shah, Nadeem W; Thornton, Steven F; Bottrell, Simon H; Spence, Michael J

    2009-01-26

    The potential for aerobic biodegradation of MTBE in a fractured chalk aquifer is assessed in microcosm experiments over 450 days, under in situ conditions for a groundwater temperature of 10 degrees C, MTBE concentration between 0.1 and 1.0 mg/L and dissolved O2 concentration between 2 and 10 mg/L. Following a lag period of up to 120 days, MTBE was biodegraded in uncontaminated aquifer microcosms at concentrations up to 1.2 mg/L, demonstrating that the aquifer has an intrinsic potential to biodegrade MTBE aerobically. The MTBE biodegradation rate increased three-fold from a mean of 6.6+/-1.6 microg/L/day in uncontaminated aquifer microcosms for subsequent additions of MTBE, suggesting an increasing biodegradation capability, due to microbial cell growth and increased biomass after repeated exposure to MTBE. In contaminated aquifer microcosms which also contained TAME, MTBE biodegradation occurred after a shorter lag of 15 or 33 days and MTBE biodegradation rates were higher (max. 27.5 microg/L/day), probably resulting from an acclimated microbial population due to previous exposure to MTBE in situ. The initial MTBE concentration did not affect the lag period but the biodegradation rate increased with the initial MTBE concentration, indicating that there was no inhibition of MTBE biodegradation related to MTBE concentration up to 1.2 mg/L. No minimum substrate concentration for MTBE biodegradation was observed, indicating that in the presence of dissolved O2 (and absence of inhibitory factors) MTBE biodegradation would occur in the aquifer at MTBE concentrations (ca. 0.1 mg/L) found at the front of the ether oxygenate plume. MTBE biodegradation occurred with concomitant O2 consumption but no other electron acceptor utilisation, indicating biodegradation by aerobic processes only. However, O2 consumption was less than the stoichiometric requirement for complete MTBE mineralization, suggesting that only partial biodegradation of MTBE to intermediate organic

  4. Effects of Soil Oxygen Conditions and Soil pH on Remediation of DDT-contaminated Soil by Laccase from White Rot Fungi

    PubMed Central

    Zhao, Yuechun; Yi, Xiaoyun

    2010-01-01

    High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5–4.5. PMID:20617049

  5. Effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase from white rot fungi.

    PubMed

    Zhao, Yuechun; Yi, Xiaoyun

    2010-04-01

    High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5-4.5. PMID:20617049

  6. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  7. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Astrophysics Data System (ADS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-03-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  8. Development of a predictive model for the growth kinetics of aerobic microbial population on pomegranate marinated chicken breast fillets under isothermal and dynamic temperature conditions.

    PubMed

    Lytou, Anastasia; Panagou, Efstathios Z; Nychas, George-John E

    2016-05-01

    The aim of this study was the development of a model to describe the growth kinetics of aerobic microbial population of chicken breast fillets marinated in pomegranate juice under isothermal and dynamic temperature conditions. Moreover, the effect of pomegranate juice on the extension of the shelf life of the product was investigated. Samples (10 g) of chicken breast fillets were immersed in marinades containing pomegranate juice for 3 h at 4 °C following storage under aerobic conditions at 4, 10, and 15 °C for 10 days. Total Viable Counts (TVC), Pseudomonas spp and lactic acid bacteria (LAB) were enumerated, in parallel with sensory assessment (odor and overall appearance) of marinated and non-marinated samples. The Baranyi model was fitted to the growth data of TVC to calculate the maximum specific growth rate (μmax) that was further modeled as a function of temperature using a square root-type model. The validation of the model was conducted under dynamic temperature conditions based on two fluctuating temperature scenarios with periodic changes from 6 to 13 °C. The shelf life was determined both mathematically and with sensory assessment and its temperature dependence was modeled by an Arrhenius type equation. Results showed that the μmax of TVC of marinated samples was significantly lower compared to control samples regardless temperature, while under dynamic temperature conditions the model satisfactorily predicted the growth of TVC in both control and marinated samples. The shelf-life of marinated samples was significantly extended compared to the control (5 days extension at 4 °C). The calculated activation energies (Ea), 82 and 52 kJ/mol for control and marinated samples, respectively, indicated higher temperature dependence of the shelf life of control samples compared to marinated ones. The present results indicated that pomegranate juice could be used as an alternative ingredient in marinades to prolong the shelf life of chicken.

  9. Degradation of 3-chlorobenzoate under low-oxygen conditions in pure and mixed cultures of the anoxygenic photoheterotroph Rhodopseudomonas palustris DCP3 and an aerobic Alcaligenes species.

    PubMed

    Krooneman, J; van den Akker, S; Pedro Gomes, T M; Forney, L J; Gottschal, J C

    1999-01-01

    The presence or absence of molecular oxygen has been shown to play a crucial role in the degradability of haloaromatic compounds. In the present study, it was shown that anaerobic phototrophic 3-chlorobenzoate (3CBA) metabolism by Rhodopseudomonas palustris DCP3 is oxygen tolerant up to a concentration of 3 microM O2. Simultaneous oxidation of an additional carbon source permitted light-dependent anaerobic 3CBA degradation at oxygen input levels which, in the absence of such an additional compound, would result in inhibition of light-dependent dehalogenation. Experiments under the same experimental conditions with strain DCP3 in coculture with an aerobic 3CBA-utilizing heterotroph, Alcaligenes sp. strain L6, revealed that light-dependent dehalogenation of 3CBA did not occur. Under both oxygen limitation (O2 < 0.1 microM) and low oxygen concentrations (3 microM O2), all the 3CBA was metabolized by the aerobic heterotroph. These data suggest that biodegradation of (halo)aromatics by photoheterotrophic bacteria such as R. palustris DCP3 may be restricted to anoxic photic environments. PMID:9872770

  10. Nitrososphaera viennensis gen. nov., sp. nov., an aerobic and mesophilic, ammonia-oxidizing archaeon from soil and a member of the archaeal phylum Thaumarchaeota

    PubMed Central

    Stieglmeier, Michaela; Klingl, Andreas; Alves, Ricardo J. E.; Rittmann, Simon K.-M. R.; Melcher, Michael; Leisch, Nikolaus

    2014-01-01

    A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76T, was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6–0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76T had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76T had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76T is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85 % 16S rRNA gene sequence identity with the closest cultivated relative ‘Candidatus Nitrosopumilus maritimus’ SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81 % 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. ‘Korarchaeota’ and ‘Aigarchaeota’). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76T. The type strain of Nitrososphaera viennensis is strain EN76T ( = DSM 26422T = JMC 19564T). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov. PMID:24907263

  11. The effect of environmental conditions and soil physicochemistry on phosphate stabilisation of Pb in shooting range soils.

    PubMed

    Sanderson, Peter; Naidu, Ravi; Bolan, Nanthi

    2016-04-01

    The stabilisation of Pb in the soil by phosphate is influenced by environmental conditions and physicochemical properties of the soils to which it is applied. Stabilisation of Pb by phosphate was examined in four soils under different environmental conditions. The effect of soil moisture and temperature on stabilisation of Pb by phosphate was examined by measurement of water extractable and bioaccessible Pb, sequential fractionation and X-ray absorption spectroscopy. The addition of humic acid, ammonium nitrate and chloride was also examined for inhibition or improvement of Pb stability with phosphate treatment. The effect of moisture level varied between soils. In soil MB and DA a soil moisture level of 50% water holding capacity was sufficient to maximise stabilisation of Pb, but in soil TV and PE reduction in bioaccessible Pb was inhibited at this moisture level. Providing moisture at twice the soil water holding capacity did not enhance the effect of phosphate on Pb stabilisation. The difference of Pb stability as a result of incubating phosphate treated soils at 18 °C and 37 °C was relatively small. However wet-dry cycles decreased the effectiveness of phosphate treatment. The reduction in bioaccessible Pb obtained was between 20 and 40% with the most optimal treatment conditions. The reduction in water extractable Pb by phosphate was substantial regardless of incubation conditions and the effect of different temperature and soil moisture regimes was not significant. Selective sequential extraction showed phosphate treatment converted Pb in fraction 1 (exchangeable, acid and water soluble) to fraction 2 (reducible). There were small difference in fraction 4 (residual) Pb and fraction 1 as a result of treatment conditions. X-ray absorption spectroscopy of stabilised PE soil revealed small differences in Pb speciation under varying soil moisture and temperature treatments. The addition of humic acid and chloride produced the greatest effect on Pb speciation in

  12. The effect of environmental conditions and soil physicochemistry on phosphate stabilisation of Pb in shooting range soils.

    PubMed

    Sanderson, Peter; Naidu, Ravi; Bolan, Nanthi

    2016-04-01

    The stabilisation of Pb in the soil by phosphate is influenced by environmental conditions and physicochemical properties of the soils to which it is applied. Stabilisation of Pb by phosphate was examined in four soils under different environmental conditions. The effect of soil moisture and temperature on stabilisation of Pb by phosphate was examined by measurement of water extractable and bioaccessible Pb, sequential fractionation and X-ray absorption spectroscopy. The addition of humic acid, ammonium nitrate and chloride was also examined for inhibition or improvement of Pb stability with phosphate treatment. The effect of moisture level varied between soils. In soil MB and DA a soil moisture level of 50% water holding capacity was sufficient to maximise stabilisation of Pb, but in soil TV and PE reduction in bioaccessible Pb was inhibited at this moisture level. Providing moisture at twice the soil water holding capacity did not enhance the effect of phosphate on Pb stabilisation. The difference of Pb stability as a result of incubating phosphate treated soils at 18 °C and 37 °C was relatively small. However wet-dry cycles decreased the effectiveness of phosphate treatment. The reduction in bioaccessible Pb obtained was between 20 and 40% with the most optimal treatment conditions. The reduction in water extractable Pb by phosphate was substantial regardless of incubation conditions and the effect of different temperature and soil moisture regimes was not significant. Selective sequential extraction showed phosphate treatment converted Pb in fraction 1 (exchangeable, acid and water soluble) to fraction 2 (reducible). There were small difference in fraction 4 (residual) Pb and fraction 1 as a result of treatment conditions. X-ray absorption spectroscopy of stabilised PE soil revealed small differences in Pb speciation under varying soil moisture and temperature treatments. The addition of humic acid and chloride produced the greatest effect on Pb speciation in

  13. Arsenopyrite weathering under conditions of simulated calcareous soil.

    PubMed

    Lara, René H; Velázquez, Leticia J; Vazquez-Arenas, Jorge; Mallet, Martine; Dossot, Manuel; Labastida, Israel; Sosa-Rodríguez, Fabiola S; Espinosa-Cristóbal, León F; Escobedo-Bretado, Miguel A; Cruz, Roel

    2016-02-01

    Mining activities release arsenopyrite into calcareous soils where it undergoes weathering generating toxic compounds. The research evaluates the environmental impacts of these processes under semi-alkaline carbonated conditions. Electrochemical (cyclic voltammetry, chronoamperometry, EIS), spectroscopic (Raman, XPS), and microscopic (SEM, AFM, TEM) techniques are combined along with chemical analyses of leachates collected from simulated arsenopyrite weathering to comprehensively examine the interfacial mechanisms. Early oxidation stages enhance mineral reactivity through the formation of surface sulfur phases (e.g., S n (2-)/S(0)) with semiconductor properties, leading to oscillatory mineral reactivity. Subsequent steps entail the generation of intermediate siderite (FeCO3)-like, followed by the formation of low-compact mass sub-micro ferric oxyhydroxides (α, γ-FeOOH) with adsorbed arsenic (mainly As(III), and lower amounts of As(V)). In addition, weathering reactions can be influenced by accessible arsenic resulting in the formation of a symplesite (Fe3(AsO4)3)-like compound which is dependent on the amount of accessible arsenic in the system. It is proposed that arsenic release occurs via diffusion across secondary α, γ-FeOOH structures during arsenopyrite weathering. We suggest weathering mechanisms of arsenopyrite in calcareous soil and environmental implications based on experimental data.

  14. Effective selenium volatilization under aerobic conditions and recovery from the aqueous phase by Pseudomonas stutzeri NT-I.

    PubMed

    Kagami, Tsubasa; Narita, Takanobu; Kuroda, Masashi; Notaguchi, Emi; Yamashita, Mitsuo; Sei, Kazunari; Soda, Satoshi; Ike, Michihiko

    2013-03-01

    Selenium is an important rare metal and its recovery from waste and wastewater is necessary for its sustainable utilization. Microbial selenium volatilization is suitable for selenium recovery from industrial wastewater because volatile selenium can be recovered in recyclable forms free from other chemicals. We found that Pseudomonas stutzeri NT-I can aerobically transform selenate, selenite, and biogenic elemental selenium into dimethyldiselenide as well as dimethylselenide; these were temporarily accumulated in the aqueous phase and then transferred into the gaseous phase. The rate of selenium volatilization using strain NT-I ranged 6.5-7.6 μmol/L/h in flask experiments and was much higher than the rates reported previously for other microbes. The selenium volatilization rate accelerated to 14 μmol/L/h in a jar fermenter. Furthermore, 82% of the selenium volatilized using strain NT-I was recovered with few impurities within 48 h in a simple gas trap with nitric acid, demonstrating that strain NT-I is a promising biocatalyst for selenium recovery through biovolatilization from the aqueous phase.

  15. Lab scale experiments using a submerged MBR under thermophilic aerobic conditions for the treatment of paper mill deinking wastewater.

    PubMed

    Simstich, Benjamin; Beimfohr, Claudia; Horn, Harald

    2012-10-01

    This paper describes the results of laboratory experiments using a thermophilic aerobic MBR (TMBR) at 50 °C. An innovative use of submerged flat-sheet MBR modules to treat circuit wastewater from the paper industry was studied. Two experiments were conducted with a flux of 8-13 L/m(2)/h without chemical membrane cleaning. COD and BOD(5) elimination rates were 83% and 99%, respectively. Calcium was reduced from 110 to 180 mg/L in the inflow to 35-60 mg/L in the permeate. However, only negligible membrane scaling occurred. The observed sludge yield was very low and amounted to 0.07-0.29 g MLSS/g COD(eliminated). Consequently, the nutrient supply of ammonia and phosphate can be lower compared to a mesophilic process. Molecular-biological FISH analysis revealed a likewise high diversity of microorganisms in the TMBR compared to the mesophilic sludge used for start-up. Furthermore, ammonia-oxidising bacteria were detected at thermophilic operation. PMID:22595101

  16. Attenuation of aqueous benzene in soils under saturated flow conditions.

    PubMed

    Kim, S-B; Kim, D-J; Yun, S-T

    2006-01-01

    The fate of aqueous benzene in subsurface was investigated in this study, focusing on the role of sorption and biodegradation on the benzene attenuation under dynamic flow conditions. Two sets of column tests were conducted in Plexiglass flow cells packed uniformly with sandy aquifer materials. The first set of the experiment was conducted with a step-type injection of benzene with different powder activated carbon (PAC) contents: (1) PAC = 0 %; (2) PAC = 0.5 %; (3) PAC = 2.0%. The second set was performed as a pulse-type with different test conditions: (4) benzene; (5) benzene and bacteria (Pseudomonas aeruginosa); (6) benzene and bacteria (P. aeruginosa) with hydrogen peroxide. In addition, numerical experiments were performed to examine the role of sorption processes on the benzene attenuation. In the step mode experiments, the KCl breakthrough curves (BTCs) reached the input concentration while the benzene BTCs were considerably lower than those of KCl with slight retardation for all cases, indicating that both reversible/retardation and irreversible sorption occurred. The pulse type tests showed that attenuation of benzene increased in the presence of bacteria due to biodegradation. The benzene attenuation by microbial degradation increased furthermore in the presence of hydrogen peroxide owing to sufficient supply of dissolved oxygen in soil column. Numerical experiments demonstrated that retardation could not contribute to the attenuation of benzene in soils but could only extend its breakthrough time. Experimental results indicated that aqueous benzene could be attenuated by irreversible sorption and biodegradation during transport through the subsurface. Additionally, the attenuation of aqueous benzene is closely related to organic carbon content and oxygen level existing in contaminated aquifers.

  17. Water Retention of Extremophiles and Martian Soil Simulants Under Close to Martian Environmental Conditions

    NASA Astrophysics Data System (ADS)

    Jänchen, J.; Bauermeister, A.; Feyh, N.; deVera, J.-P.

    2012-05-01

    We report data about interaction of moisture with soil simulants and extremophiles under Martian environmental conditions contributing on atmosphere/surface modelling and on effects determining the water inventory of the upper soil layer of Mars.

  18. Can arbuscular mycorrhizal fungi improve grain yield, As uptake and tolerance of rice grown under aerobic conditions?

    PubMed

    Li, H; Ye, Z H; Chan, W F; Chen, X W; Wu, F Y; Wu, S C; Wong, M H

    2011-10-01

    The effects of arbuscular mycorrhizal fungi (AMF) -Glomus intraradices and G. geosporum on arsenic (As) and phosphorus (P) uptake by lowland (Guangyinzhan) and upland rice (Handao 502) were investigated in soil, spiked with and without 60 mg As kg(-1). In As-contaminated soil, Guangyinzhan inoculated with G. intraradices or Handao 502 inoculated with G. geosporum enhanced As tolerance, grain P content, grain yield. However, Guangyinzhan inoculated with G. geosporum or Handao 502 inoculated with G. intraradices decreased grain P content, grain yield and the molar ratio of grain P/As content, and increased the As concentration and the ratio of grain/straw As concentration. These results show that rice/AMF combinations had significant (p < 0.05) effects on grain As concentration, grain yield and grain P uptake. The variation in the transfer and uptake of As and P reflected strong functional diversity in AM (arbuscular mycorrhizal) symbioses. PMID:21737190

  19. Wireless sensor network for monitoring soil moisture and weather conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network (WSN) was developed and deployed in three fields to monitor soil water status and collect weather data for irrigation scheduling. The WSN consists of soil-water sensors, weather sensors, wireless data loggers, and a wireless modem. Soil-water sensors were installed at three...

  20. Healthy soil as a necessary condition of human life

    NASA Astrophysics Data System (ADS)

    Sokolov, M. S.; Dorodnykh, Yu. L.; Marchenko, A. I.

    2010-07-01

    The extent of soil degradation and soil pathology in Russia is discussed. The concept of a federal target program “National System of the Chemical and Biological Security of the Russian Federation (2009-2013)” is examined. A definition is given to healthy soil of agrocenoses and its main functional characteristic—ecological stability (including balanced biodiversity, self-cleaning capacity, and suppressive activity of the phytopedocenosis). Urgent applied scientific problems of regional soil sanitation are formulated. Criteria and modern methods of ecological monitoring and assessment of soil quality and health are considered. A systems approach to sanitation of soils infected by highly harmful phytopathogens—the causative agents of root rots of cereal crops—is demonstrated using the induction of soil suppressiveness as an example.

  1. Determination of arsenic species in soil solution under flooded conditions

    SciTech Connect

    Onken, B.M.; Hossner, L.R.

    1996-09-01

    Greenhouse experiments were conducted to evaluate the relationships between the species and concentrations of As in the soil solution of flooded soils with other parameters including soil pe, pH, Fe, Mn, and type and amount of As added. Two soils were treated with 0, 5, 15, 25, 35, and 45 mg As kg{sup -1} soil added as either Na-arsenate or Na-arsenite and planted with rice (Oryza sativa L.). Soil solution samples were collected during a period of 60 d and analyzed for As. Selective hydrides generation was employed to evaluate both type and quality of As present in the samples. Inorganic As in the form of arsenate and arsenite was found in the soil solution of both soils. The conversion of added arsenite to arsenate occurred within the first 10 d of the experiment when the pe/pH of the soil was not conducive to arsenite stability. Added arsenate was converted to arsenite during the source of the experiment as the pe/pH of the soil declined due to flooding. Arsenate reached a maximum in soil solution at 10 to 20 d after flooding while maximum arsenite concentrations occurred at 20 to 30 d after flooding. The total concentration of As in soil solution generally reached a maximum at 20 to 30 d after flooding, after which time precipitous losses of As from soil solution occurred in all but the highest As treatments. Soil solution As concentrations were not statistically different between planted and unplanted controls. 30 refs., 6 figs., 3 tabs.

  2. Constitutive expression of Campylobacter jejuni truncated hemoglobin CtrHb improves the growth of Escherichia coli cell under aerobic and anaerobic conditions.

    PubMed

    Yang, Jiang-Ke; Xiong, Wei; Xu, Li; Li, Jia; Zhao, Xiu-Ju

    2015-01-01

    Bacteria hemoglobin could bind to the oxygen, transfer it from the intracellular microenvironment to the respiration process and sustain the energy for the metabolism and reproduction of cells. Heterologous expression of bacteria hemoglobin gene could improve the capacity of the host on oxygen-capturing and allow it to grow even under microaerophilic condition. To develop a system based on hemoglobin to help bacteria cells overcome the oxygen shortage in fermentation, in this study, Campylobacter jejuni truncated hemoglobin (CtrHb) gene was synthesized and expressed under the control of constitutive expression promoters P2 and P(SPO1-II) in Escherichia coli. As showed by the growth curves of the two recombinants P2-CtrHb and P(SPO1-II)-CtrHb, constitutive expression of CtrHb improved cell growth under aerobic shaking-flasks, anaerobic capped-bottles and bioreactor conditions. According to the NMR analysis, this improvement might come from the expression of hemoglobin which could boost the metabolism of cells by supplying more oxygen to the respiratory chain processes. Through semi-quantitative RT-PCR and CO differential spectrum assays, we further discussed the connection between the growth patterns of the recombinants, the expression level of CtrHb and oxygen binding capacity of CtrHb in cells. Based on the growth patterns of these recombinants in bioreactor, a possible choice on different type of recombinants under specific fermentation conditions was also suggested in this study.

  3. The effect of salinization and freshening events in coastal aquifers on nutrient characteristics as deduced from column experiments under aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Russak, A.; Sivan, O.; Herut, B.; Lazar, B.; Yechieli, Y.

    2015-10-01

    This study experimentally quantified the effect of seawater intrusion (salinization) and freshening events in coastal aquifers on nutrient (N, P and DSi) dynamics across the fresh-saline groundwater interface. Laboratory column experiments were conducted under aerobic and anaerobic conditions in order to simulate the processes occurring in the fresh-saline interface. They were performed with aquifer sediments, simulating the natural conditions during alterations of natural fresh groundwater to seawater and vice versa. The salinization and freshening experiments showed that NH4+ and PO43- and DSi were affected mainly by ion exchange processes while microbial activity controlled the nitrogen species NO3- and NO2-. Due to the cation exchange, salinization generated enrichment (above the expected conservative behavior) of NH4+, up to 80 μmol L-1 (an order of magnitude higher than in seawater or fresh groundwater). Under anaerobic conditions NO3- was removed by denitrification, as demonstrated by the decrease in NO3- concentrations, the increase in NO2- concentrations, and the increase in δ15N by 15-25‰. Clear evidence was shown for anion exchange of PO43-, which competes with HCO3- and boron on adsorption sites. DSi seems to take part in the exchange process, similar to PO43-.

  4. Constitutive expression of Campylobacter jejuni truncated hemoglobin CtrHb improves the growth of Escherichia coli cell under aerobic and anaerobic conditions.

    PubMed

    Yang, Jiang-Ke; Xiong, Wei; Xu, Li; Li, Jia; Zhao, Xiu-Ju

    2015-01-01

    Bacteria hemoglobin could bind to the oxygen, transfer it from the intracellular microenvironment to the respiration process and sustain the energy for the metabolism and reproduction of cells. Heterologous expression of bacteria hemoglobin gene could improve the capacity of the host on oxygen-capturing and allow it to grow even under microaerophilic condition. To develop a system based on hemoglobin to help bacteria cells overcome the oxygen shortage in fermentation, in this study, Campylobacter jejuni truncated hemoglobin (CtrHb) gene was synthesized and expressed under the control of constitutive expression promoters P2 and P(SPO1-II) in Escherichia coli. As showed by the growth curves of the two recombinants P2-CtrHb and P(SPO1-II)-CtrHb, constitutive expression of CtrHb improved cell growth under aerobic shaking-flasks, anaerobic capped-bottles and bioreactor conditions. According to the NMR analysis, this improvement might come from the expression of hemoglobin which could boost the metabolism of cells by supplying more oxygen to the respiratory chain processes. Through semi-quantitative RT-PCR and CO differential spectrum assays, we further discussed the connection between the growth patterns of the recombinants, the expression level of CtrHb and oxygen binding capacity of CtrHb in cells. Based on the growth patterns of these recombinants in bioreactor, a possible choice on different type of recombinants under specific fermentation conditions was also suggested in this study. PMID:26047918

  5. Isolation of high-salinity-tolerant bacterial strains, Enterobacter sp., Serratia sp., Yersinia sp., for nitrification and aerobic denitrification under cyanogenic conditions.

    PubMed

    Mpongwana, N; Ntwampe, S K O; Mekuto, L; Akinpelu, E A; Dyantyi, S; Mpentshu, Y

    2016-01-01

    Cyanides (CN(-)) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH(4)-N in the presence of 65.91 mg/L of free cyanide (CN(-)) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH(4)-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h(-1) (I), 4.21 h(-1) (H) and 3.79 h(-1) (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH. PMID:27148718

  6. The Impact of Organic Amendments on Soil Properties Under Mediterranean Climatic Conditions

    NASA Astrophysics Data System (ADS)

    Hueso Gonzalez, Paloma; Francisco Martinez Murillo, Juan; Damian Ruiz Sinoga, Jose

    2014-05-01

    Soil erosion and unsustainable land uses produce adverse effect on SOC content. Soil management techniques and corrections can be applied for soil recovery, especially, with afforestation purposes. This study presents the short term effects of the application of different treatments and amendments on soil properties for soils included in several sets of closed plots located in the experimental area of Pinarillo (Nerja, Spain). The analysed soil properties were: pH, EC, Organic Carbon, total Nitrogen and total Carbon. In order to verify possible differences, we applied the test of Mann-Whitney U in corroboration with the previous homogeneity test of variance. The result of each strategy set compared to the initial condition shows at least one significant modification in the analysed soil properties. Electrical conductivity was the most changeable soil property respect to the initial condition. Similarly, organic carbon content and total organic carbon remained quite similar. However, when all of the strategy sets are compared among them, total carbon was the most significantly changeable property. Mulching, polymers and urban residue seem to highly modify the soil initial conditions. Although soil physic-chemical parameters generally used to evaluate soil quality change very slowly. The analysed soil properties shows significant differences between dry and wet season. This fact, could be indicating the effect of certain seasonality as it is usual in Mediterranean condition.

  7. Radiochlorine concentration ratios for agricultural plants in various soil conditions.

    PubMed

    Kashparov, V; Colle, C; Levchuk, S; Yoschenko, V; Zvarich, S

    2007-01-01

    Long-term field experiments have been carried out in the Chernobyl exclusion zone in order to determine the parameters governing radiochlorine ((36)Cl) transfer to plants from four types of soil, namely, Podzoluvisol, Greyzem, Phaeozem and Chernozem. Radiochlorine concentration ratios (CR=concentration of (36)Cl in the fresh plant material divided by its concentration in the dried soil in the upper 20 cm layer) were obtained in green peas (2.6+/-0.4), onions (1.5+/-0.5), potatoes (8+/-1), clover (90+/-26) and ryegrass (158+/-88) hay, oat seeds (36+/-23) and straw (305+/-159), wheat seeds (35+/-10) and straw (222+/-82). These values correlate with the stable chlorine values for the same plants. It was shown that (36)Cl plant/soil CR in radish roots (CR=9.7+/-1.4) does not depend on the stable chlorine content in the soil (up to 150 mgkg(-1)), soil type and thus, that stable chlorine CR values (9.4+/-1.2) can also be used for (36)Cl. Injection of additional quantities of stable chlorine into the soil (100 mgkg(-1) of dry soil) with fertilizer does not change the soil-to-plant transfer of (36)Cl. The results from a batch experiment showed that chlorine is retained in the investigated soils only by live biota and transfers quickly (in just a few hours) into the soil solution from dry vegetation even without decomposition of dead plants and is integrated in the migration processes in soil.

  8. Black locust--successful invader of a wide range of soil conditions.

    PubMed

    Vítková, Michaela; Tonika, Jaroslav; Müllerová, Jana

    2015-02-01

    Black locust (Robinia pseudoacacia, BL), a species native to North America, has successfully invaded many types of habitats over the world. This study provides an overall assessment of BL soil conditions to determine the range of physical-chemical soil properties it can tolerate. 511 BL stands (for the soil types) and 33 permanent plots (for the soil chemistry) were studied in the Czech Republic. Relationships among different environmental variables (physical-chemical soil properties, vegetation characteristics and habitat conditions) were investigated and variables with the highest effect on species composition were detected. The results were compared with data in the literature for other parts of the secondary and native distributions of this species. This assessment showed that BL is able to tolerate extremely diverse soil physical-chemical conditions, from extremely acid to strongly alkaline, and from medium to highly base saturated soils with a gradient of different subsurface stoniness. Soil nitrate, N mineralization and nitrification rates also varied considerably and the concentrations of exchangeable phosphorus and ammonium were consistently low. N mineralization rate, incubated inorganic nitrogen and nitrates were positively correlated with base saturation and cation exchange capacity. The most common soil types were young soils (Cambisols, Leptosols, Arenosols, and coarsely textured Fluvisols). BL seems to be limited by water supply and soil aeration and prefers well aerated and drained soils, and tolerates desiccation but avoids compact soils and areas where the soils are frequently waterlogged. On steep slopes, BL was less vigorous, stunted and less competitive. By contrast, the tallest BL trees were found on sandy soils in a flat landscape. Number and share of nitrophytes in the herb layer were positively related to basic bedrock, soil reaction and N-NO3/N ratio. Soil reaction was determined as the most important environmental characteristic

  9. Greenhouse gas emissions from soil under changing environmental conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This manuscript is the Guest Editors’ Introduction to a special issue on greenhouse gas emissions from agriculture. The papers were assembled following presentation at EuroSoil 2012. Exchange of greenhouse gases between soils and the atmosphere is a natural consequence of several ecosystem process...

  10. [Morphology of soil iron oxides and its correlation with soil-forming process and forming conditions in a karst mountain].

    PubMed

    Zhang, Zhi-Wei; Zhu, Zhang-Xiong; Fu, Wa-Li; Wen, Zhi-Lin

    2012-06-01

    The quantity and morphology of iron oxides are indicators of soil forming-process and forming conditions. In order to analyze the connection between soil iron oxides and soil forming conditions and degenerative process of karst ecosystem, we have chosen 14 soil profiles on the top and middle section of Jinfo Mountain, a typical karst slope in Chongqing, China. Morphology and contents of soil iron oxides were studied by using chemical selective extraction techniques. We draw conclusions: 1) total iron (Fe(t)) is mainly controlled by parent material and lithology. Significant difference of Fe(t) content exists between soils in Top Mountain (51.49 g x kg(-1), mean value from 5 profiles) and soils at the middle sector of North Slope (86.29 g x kg(-1), mean value of 9 profiles); 2) the results show low concentration of F(d) (29.16 g x kg(-1)) and low ratio of Fe(d) to Fe(t)(35.40%) in soil clay under conditions of high elevation and low temperature on Top Mountain. In contrast, the results indicate advanced weathering and soil-forming process at middle slope sites due to high temperature; this is supported by high mean values of Fe(d) (43.92 g x kg(-1)) and ratio of Fe(d)/Fe(t) in clay (60.41%); 3) long humid climatic setting and large numbers of soil organic matter on top of the mountain result in high activation degrees (F(o)/Fe(d)) and high complexation degrees (Fe(p)/Fe(d)); mean values of them are 73.51%, 17.21% respectively, which are higher than that of soils at middle slope sites (13.06%, 0.41%); 4) after degradation or deforestation of secondary forestland (pines massoniana among bushes) at middle section of the hillslope, soil free iron oxides (Fe(d)) and total iron oxides (Fe(t)) decrease as well as soil organic carbon and clay, because of progressively increasing of soil erosion. Average contents of Fe(t) and Fe(d) in clay from 2 shrub profiles are 98.25 g x kg(-1), 50.81 g x kg(-1) respectively. However, the four tillage soils we have studied reveal lower

  11. Microbial aerobic and anaerobic degradation of acrylamide in sludge and water under environmental conditions--case study in a sand and gravel quarry.

    PubMed

    Guezennec, A G; Michel, C; Ozturk, S; Togola, A; Guzzo, J; Desroche, N

    2015-05-01

    Polyacrylamides (PAMs) are used in sand and gravel quarries as water purification flocculants for recycling process water in a recycling loop system where the flocculants remove fine particles in the form of sludge. The PAM-based flocculants, however, contain residual amounts of acrylamide (AMD) that did not react during the polymerization process. This acrylamide is released into the environment when the sludge is discharged into a settling basin. Here, we explore the microbial diversity and the potential for AMD biodegradation in water and sludge samples collected in a quarry site submitted to low AMD concentrations. The microbial diversity, analyzed by culture-dependent methods and the denaturing gradient gel electrophoresis approach, reveals the presence of Proteobacteria, Cyanobacteria, and Actinobacteria, among which some species are known to have an AMD biodegradation activity. Results also show that the two main parts of the water recycling loop-the washing process and the settling basin-display significantly different bacterial profiles. The exposure time with residual AMD could, thus, be one of the parameters that lead to a selection of specific bacterial species. AMD degradation experiments with 0.5 g L(-1) AMD showed a high potential for biodegradation in all parts of the washing process, except the make-up water. The AMD biodegradation potential in samples collected from the washing process and settling basin was also analyzed taking into account on-site conditions: low (12 °C) and high (25 °C) temperatures reflecting the winter and summer seasons, and AMD concentrations of 50 μg L(-1). Batch tests showed rapid (as little as 18 h) AMD biodegradation under aerobic and anaerobic conditions at both the winter and summer temperatures, although there was a greater lag time before activity started with the AMD biodegradation at 12 °C. This study, thus, demonstrates that bacteria present in sludge and water samples exert an in situ and rapid

  12. SUBSURFACE SOIL CONDITIONS BENEATH AND NEAR BUILDINGS AND THE POTENTIAL EFFECTS ON SOIL VAPOR INTRUSION

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion. Volatile organic chemicals in contaminated soils or groundwater can emit vapors that may migrate through subsurface soils and enter indoor air spaces of overlying buildings. T...

  13. Alkanindiges illinoisensis gen. nov., sp. nov., an obligately hydrocarbonoclastic, aerobic squalane-degrading bacterium isolated from oilfield soils.

    PubMed

    Bogan, Bill W; Sullivan, Wendy R; Kayser, Kevin J; Derr, K D; Aldrich, Henry C; Paterek, J Robert

    2003-09-01

    An alkane-degrading bacterium, designated GTI MVAB Hex1(T), was isolated from chronically crude oil-contaminated soil from an oilfield in southern Illinois. The isolate grew very weakly or not at all in minimal or rich media without hydrocarbons. Straight-chain aliphatic hydrocarbons, such as hexadecane and heptadecane, greatly stimulated growth; shorter-chain (

  14. Mobility of spiromesifen in packed soil columns under laboratory conditions.

    PubMed

    Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

    2014-11-01

    On percolating water equivalent to 1,156 mm of rainfall, spiromesifen formulation did not leach out of 25-cm long columns, and 62.7 % of this was recovered in 5-10-cm soil depth. In columns treated with the analytical grade, 52.40 % of the recovered spiromesifen was confined to 0-5-cm soil depth, with 0.04 % in leachate fraction, suggesting high adsorption in soil. Results revealed that percolating 400 mL of water, residues of enol metabolite of spiromesifen was detected up to 20-25-cm soil layer, with 23.50 % residues of spiromesifen in this layer and 1.73 % in the leachate fraction indicating that metabolite is more mobile as compared to the parent compound. Results suggested a significant reduction in leaching losses of enol metabolite in amended soil columns with 5 % nano clay, farmyard manure (FYM), and vermicompost. No enol spiromesifen was recovered in the leachate in columns amended with nano clay, vermicompost, and FYM; however, 85.30, 70.5, and 65.40 %, respectively, was recovered from 0-5 cm-soil depth of column after percolating water equivalent to 1,156 mm of rainfall. Spiromesifen formulation is less mobile in sandy loam soil than analytical grade spiromesifen. The metabolite, enol spiromesifen, is relatively more mobile than the parent compound and may leach into groundwater. The study suggested that amendments were very effective in reducing the downward mobility of enol metabolite in soil column. Further, it resulted in greater retention of enol metabolite in the amendment application zone. PMID:25060860

  15. Quantifying factors limiting aerobic degradation during aerobic bioreactor landfilling.

    PubMed

    Yazdani, Ramin; Mostafid, M Erfan; Han, Byunghyun; Imhoff, Paul T; Chiu, Pei; Augenstein, Don; Kayhanian, Masoud; Tchobanoglous, George

    2010-08-15

    A bioreactor landfill cell at Yolo County, California was operated aerobically for six months to quantify the extent of aerobic degradation and mechanisms limiting aerobic activity during air injection and liquid addition. The portion of the solid waste degraded anaerobically was estimated and tracked through time. From an analysis of in situ aerobic respiration and gas tracer data, it was found that a large fraction of the gas-filled pore space was in immobile zones where it was difficult to maintain aerobic conditions, even at relatively moderate landfill cell-average moisture contents of 33-36%. Even with the intentional injection of air, anaerobic activity was never less than 13%, and sometimes exceeded 65%. Analyses of gas tracer and respiration data were used to quantify rates of respiration and rates of mass transfer to immobile gas zones. The similarity of these rates indicated that waste degradation was influenced significantly by rates of oxygen transfer to immobile gas zones, which comprised 32-92% of the gas-filled pore space. Gas tracer tests might be useful for estimating the size of the mobile/immobile gas zones, rates of mass transfer between these regions, and the difficulty of degrading waste aerobically in particular waste bodies. PMID:20704218

  16. Nitrogen mineralization, immobilization, and nitrification following urea fertilization of a forest soil under field and laboratory conditions

    SciTech Connect

    Johnson, D.W.; Edwards, N.T.; Todd, D.E.

    1980-05-01

    Following a 200-kg urea-N/ha fertilization in a loblolly pine stand (Pinus taeda), soil mineral N levels (almost entirely NH/sub 4//sup +/) declined from 200 ppM 20 days after fertilization to < 10 ppM within 161 days. Similar patterns had been previously observed following urea fertilization in a Douglas-fir stand. After the decline in soil mineral N, 20% (40 ppM) of fertilizer N was mineralized within 4 weeks of aerobic incubation in the laboratory at 25/sup 0/C. Nitrogen mineralization in control soils did not occur after 7 weeks incubation.

  17. Biotoxicity of Mars soils: 1. Dry deposition of analog soils on microbial colonies and survival under Martian conditions

    NASA Astrophysics Data System (ADS)

    Schuerger, Andrew C.; Golden, D. C.; Ming, Doug W.

    2012-11-01

    Six Mars analog soils were created to simulate a range of potentially biotoxic geochemistries relevant to the survival of terrestrial microorganisms on Mars, and included basalt-only (non-toxic control), salt, acidic, alkaline, aeolian, and perchlorate rich geochemistries. Experiments were designed to simulate the dry-deposition of Mars soils onto spacecraft surfaces during an active descent landing scenario with propellant engines. Six eubacteria were initially tested for tolerance to desiccation, and the spore-former Bacillus subtilis HA101 and non-spore former Enterococcus faecalis ATCC 29212 were identified to be strongly resistant (HA101) and moderately resistant (29212) to desiccation at 24 °C. Furthermore, tests with B. subtilis and E. faecalis demonstrated that at least 1 mm of Mars analog soil was required to fully attenuate the biocidal effects of a simulated Mars-normal equatorial UV flux. Biotoxicity experiments were conducted under simulated Martian conditions of 6.9 mbar, -10 °C, CO2-enriched anoxic atmosphere, and a simulated equatorial solar spectrum (200-1100 nm) with an optical depth of 0.1. For B. subtilis, the six analog soils were found, in general, to be of low biotoxicity with only the high salt and acidic soils exhibiting the capacity to inactivate a moderate number of spores (<1 log reductions) exposed 7 days to the soils under simulated Martian conditions. In contrast, the overall response of E. faecalis to the analog soils was more dramatic with between two and three orders of magnitude reductions in viable cells for most soils, and between six and seven orders of magnitude reductions observed for the high-salt soil. Results suggest that Mars soils are likely not to be overtly biotoxic to terrestrial microorganisms, and suggest that the soil geochemistries on Mars will not preclude the habitability of the Martian surface.

  18. The impact of standard preparation practice on the runoff and soil erosion rates under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Khaledi Darvishan, Abdulvahed; Homayounfar, Vafa; Hamidreza Sadeghi, Seyed

    2016-09-01

    The use of laboratory methods in soil erosion studies, rainfall simulation experiments, Gerlach troughs, and other measurements such as ring infiltrometer has been recently considered more and more because of many advantages in controlling rainfall properties and high accuracy of sampling and measurements. However, different stages of soil removal, transfer, preparation and placement in laboratory plots cause significant changes in soil structure and, subsequently, the results of runoff, sediment concentration and soil loss. Knowing the rate of changes in sediment concentration and soil loss variables with respect to the soil preparation for laboratory studies is therefore inevitable to generalize the laboratory results to field conditions. However, there has been little attention given to evaluate the effects of soil preparation on sediment variables. The present study was therefore conducted to compare sediment concentration and soil loss in natural and prepared soil. To achieve the study purposes, 18 field 1 × 1 m plots were adopted in an 18 % gradient slope with sandy-clay-loam soil in the Kojour watershed, northern Iran. A portable rainfall simulator was then used to simulate rainfall events using one or two nozzles of BEX: 3/8 S24W for various rainfall intensities with a constant height of 3 m above the soil surface. Three rainfall intensities of 40, 60 and 80 mm h-1 were simulated on both prepared and natural soil treatments with three replications. The sediment concentration and soil loss at five 3 min intervals after time to runoff were then measured. The results showed the significant increasing effects of soil preparation (p ≤ 0.01) on the average sediment concentration and soil loss. The increasing rates of runoff coefficient, sediment concentration and soil loss due to the study soil preparation method for laboratory soil erosion plots were 179, 183 and 1050 % (2.79, 2.83 and 11.50 times), respectively.

  19. Effects of agricultural practices of three crops on the soil communities under Mediterranean conditions: field evaluation.

    NASA Astrophysics Data System (ADS)

    Leitão, Sara; José Cerejeira, Maria; Abreu, Manuela; Sousa, José Paulo

    2014-05-01

    Sustainable agricultural production relies on soil communities as the main actors in key soil processes necessary to maintain sustainable soil functioning. Soil biodiversity influences soil physical and chemical characteristics and thus the sustainability of crop and agro-ecosystems functioning. Agricultural practices (e.g.: soil tillage, pesticides and fertilizer applications, irrigation) may affects negatively or positively soil biodiversity and abundances by modifying the relationships between organisms in the soil ecosystem. The present study aimed to study the influence of agricultural practices of three crops (potato, onion and maize) under Mediterranean climate conditions on soil macro- and mesofauna during their entire crop cycles. Effects on soil communities were assessed at a higher tier of environmental risk assessment comprising field testing of indigenous edaphic communities in a selected study-site located in a major agriculture region of Central Portugal, Ribatejo e Oeste, neighbouring protected wetlands. A reference site near the agricultural field site was selected as a Control site to compare the terrestrial communities' composition and variation along the crop cycle. The field soil and Control site soil are sandy loam soils. Crops irrigation was performed by center-pivot (automated sprinkler that rotates in a half a circle area) and by sprinklers. Soil macro- and mesofauna were collected at both sites (field and Control) using two methodologies through pitfall trapping and soil sampling. The community of soil macro- and mesofauna of the three crops field varied versus control site along the crops cycles. Main differences were due to arachnids, coleopterans, ants and adult Diptera presence and abundance. The feeding activity of soil fauna between control site and crop areas varied only for potato and onion crops vs. control site but not among crops. Concentration of pesticides residues in soil did not cause apparent negative effects on the soil

  20. Biodegradability of Poly-3-hydroxybutyrate/Bacterial Cellulose Composites under Aerobic Conditions, Measured via Evolution of Carbon Dioxide and Spectroscopic and Diffraction Methods.

    PubMed

    Ruka, Dianne R; Sangwan, Parveen; Garvey, Christopher J; Simon, George P; Dean, Katherine M

    2015-08-18

    Poly-3-hydroxybutyrate (PHB) and bacterial cellulose (BC) are both natural polymeric materials that have the potential to replace traditional, nonrenewable polymers. In particular, the nanofibrillar form of bacterial cellulose makes it an effective reinforcement for PHB. Neat PHB, bacterial cellulose, and a composite of PHB/BC produced with 10 wt % cellulose were composted under accelerated aerobic test conditions, with biodegradability measured by the carbon dioxide evolution method, in conjunction with spectroscopic and diffraction methods to assess crystallinity changes during the biodegradation process. The PHB/BC composite biodegraded at a greater rate and extent than that of PHB alone, reaching 80% degradation after 30 days, whereas PHB did not reach this level of degradation until close to 50 days of composting. The relative crystallinity of PHB and PHB in the PHB/BC composite was found to increase in the initial weeks of degradation, with degradation occurring primarily in the amorphous region of the material and some recrystallization of the amorphous PHB. Small angle X-ray scattering indicates that the change in PHB crystallinity is accompanied by a change in morphology of semicrystalline lamellae. The increased rate of biodegradability suggests that these materials could be applicable to single-use applications and could rapidly biodegrade in compost on disposal.

  1. Modelling agricultural suitability along soil transects under current conditions and improved scenario of soil factors

    NASA Astrophysics Data System (ADS)

    Abd-Elmabod, Sameh K.; Jordán, Antonio; Fleskens, Luuk; van der Ploeg, Martine; Muñoz-Rojas, Miriam; Anaya-Romero, María; van der Salm, Renée J.; De la Rosa, Diego

    2015-04-01

    Agricultural land suitability analysis and improvement of soils by addressing major limitations may be a strategy for climate change adaptation. This study aims to investigate the influence of topography and variability of soil factors on the suitability of 12 annual, semiannual and perennial Mediterranean crops in the province of Seville (southern Spain). In order to represent the variability in elevation, lithology and soil, two latitudinal and longitudinal (S-N and W-E) soil transects (TA and TB) were considered including 63 representative points at regular 4 km intervals. These points were represented by 41 soil profiles from the SDBm soil database -Seville. Almagra model, a component of the agro-ecological decision support system MicroLEIS, was used to assess soil suitability. Results were grouped into five soil suitability classes: S1-optimum, S2-high, S3-moderate, S4-marginal and S5-not suitable. Each class was divided in subclasses according to the main soil limiting factors: depth (p), texture (t), drainage (d), carbonate content (c), salinity (s), sodium saturation (a), and the degree of development of the soil profile (g). This research also aimed to maximize soil potential by improving limiting factors d, c, s and a after soil restoration. Therefore, management techniques were also considered as possible scenarios in this study. The results of the evaluation showed that soil suitability ranged between S1 and S5p - S5s along of the transects. In the northern extreme of transect TA, high content of gravels and coarse texture are limiting factors (soils are classified as S4t) In contrast, the limiting factor in the eastern extreme of transect TB is the shallow useful depth (S5p subclass). The absence of calcium carbonate becomes a limiting factor in some parts of TA. In contrast, the excessive content of calcium carbonate appeared to be a limiting factor for crops in some intermediate points of TB transect. For both transects, soil salinity is the main

  2. Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

    PubMed

    Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O

    2014-09-01

    During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the

  3. Tellurite-mediated damage to the Escherichia coli NDH-dehydrogenases and terminal oxidases in aerobic conditions.

    PubMed

    Díaz-Vásquez, Waldo A; Abarca-Lagunas, María J; Cornejo, Fabián A; Pinto, Camilo A; Arenas, Felipe A; Vásquez, Claudio C

    2015-01-15

    Escherichia coli exposed to tellurite shows augmented membrane lipid peroxidation and ROS content. Also, reduced thiols, protein carbonylation, [Fe-S] center dismantling, and accumulation of key metabolites occur in these bacteria. In spite of this, not much is known about tellurite effects on the E. coli electron transport chain (ETC). In this work, tellurite-mediated damage to the E. coli ETC's NADH dehydrogenases and terminal oxidases was assessed. Mutant lacking ETC components showed delayed growth, decreased oxygen consumption and increased ROS in the presence of the toxicant. Membranes from tellurite-exposed E. coli exhibited decreased oxygen consumption and dNADH/NADH dehydrogenase activity, showing an impairment of NDH-I but not of NDH-II activity. Regarding terminal oxidases, only the bo oxidase complex was affected by tellurite. When assaying NDH-I and NDH-II activity in the presence of superoxide, the NDH-I complex was preferentially damaged. The activity was partly restored in the presence of reducing agents, sulfide and Fe(2+) under anaerobic conditions, suggesting that damage affects NDH-I [4Fe-4S] centers. Finally, augmented membrane protein oxidation along with reduced oxidase activity was observed in the presence of the toxicant. Also, the increased expression of genes encoding alternative terminal oxidases probably reflects a cell's change towards anaerobic respiration when facing tellurite. PMID:25447814

  4. Hydrogen photoproduction by nutrient-deprived Chlamydomonas reinhardtii cells immobilized within thin alginate films under aerobic and anaerobic conditions.

    PubMed

    Kosourov, Sergey N; Seibert, Michael

    2009-01-01

    A new technique for immobilizing H2-photoproducing green algae within a thin (<400 microm) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 microg Chl mL(-1) of matrix), (b) kinetics of H2 photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 micromol mg(-1) Chl h(-1)) of H2 evolution, (d) light conversion efficiencies to H2 of over 1% and (e) unexpectedly high resistance of the H2-photoproducing system to inactivation by atmospheric O2. The algal cells, entrapped in alginate and then placed in vials containing 21% O2 in the headspace, evolved up to 67% of the H2 gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H2-producing system to inactivation by O2 depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O2 in the liquid and headspace and restrict O2 diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications. PMID:18823051

  5. Nitrogen release from rock and soil under simulated field conditions

    USGS Publications Warehouse

    Holloway, J.M.; Dahlgren, R.A.; Casey, W.H.

    2001-01-01

    A laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate. Two rock types containing nitrogen, slate (1370 mg N kg-1) and greenstone (480 mg N kg-1), were used along with saprolite and BC horizon sand from soils derived from these rock types. The fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season. Nitrogen was released from rock and soil materials at rates between 10-20 and 10-19 mo1 N cm-2 s-1. Results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the BC horizon of both soils. Concentrations of mineral nitrogen (NO3- + NH4+) in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching. This seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a KCl solution. Estimates based on these laboratory release rates bracket stream water NO3-N fluxes and changes in the available mineral nitrogen pool over the active leaching period. These results confirm that geologic nitrogen, when present, may be a large and reactive pool that may contribute as a non-point source of nitrate contamination to surface and ground waters. ?? 2001 Elsevier Science B.V. All rights reserved.

  6. Hydrogen Photoproduction by Nutrient-Deprived Chalamydomonas reinhardtii Cells Immobilized Within Thin Alginate Films Under Aerobic and Anaerobic Conditions

    SciTech Connect

    Kosourov, S. N.; Seibert, M.

    2009-01-01

    A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells, entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 2} depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O{sub 2} in the liquid and headspace and restrict O{sub 2} diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications.

  7. Optimization of operation conditions for the mitigation of nitrous oxide (N2O) emissions from aerobic nitrifying granular sludge system.

    PubMed

    Liu, Rui-Ting; Wang, Xin-Hua; Zhang, Yan; Wang, Ming-Yu; Gao, Ming-Ming; Wang, Shu-Guang

    2016-05-01

    The optimization of operation parameters is a key consideration to minimize nitrous oxide (N2O) emissions in biological nitrogen removal processes. So far, different parameters have only been investigated individually, making it difficult to compare their specific effects and combined influences. In this study, we applied the Plackett-Burman (PB) multifactorial experimental design and response surface methodology (RSM) analysis to find the optimized condition for the mitigation of N2O release in a nitrifying granular sludge system. Seven parameters (temperature, pH, feeding strategy, C/N ratio, aeration rate, Cu(2+) concentration, and aeration mode) were tested in parallel. Five of them (other than chemical oxygen demand/nitrogen (C/N) ratio and Cu(2+) concentration) were selected as influential factors. Since the type of feeding strategies and aeration modes cannot be quantified, continuous feed strategy and anoxic/oxic aeration mode were applied for the following study. Influences of temperature, pH, and aeration rate on N2O emissions were tested with RSM analysis to further investigate the mutual interactions among the parameters and to identify the optimal values that would minimize N2O release. Results showed the minimum emission value could be obtained under the temperature of 22.3 °C, pH of 7.1 and aeration rate of 0.20 m(3)/h. Predicted results were then verified by subsequent validation experiments. The estimated N2O emission value of each design by RSM was also observed in good relationships with experimental result.

  8. Release of Pharmaceuticals under Reducing Conditions in a Wastewater-Irrigated Mexican Soil.

    PubMed

    Dalkmann, Philipp; Dresemann, Tim-Fabian; Siebe, Christina; Mansfeldt, Tim; Amelung, Wulf; Siemens, Jan

    2014-11-01

    Wastewater irrigation is often performed by flood irrigation, leading to changes in redox potential (Eh) of irrigated soils. In addition to soil organic matter, Fe-(hydr)oxides are important sorbents for pollutants, and biotransformation of pollutants can be accelerated under reducing conditions. Here, the influence of reducing conditions on the release of sorbed pharmaceuticals from soil and their potential accelerated dissipation was investigated in a microcosm study. Samples of a soil from the Mezquital Valley (Mexico) irrigated for 85 yr with untreated wastewater were incubated under oxidizing (Eh of 500 ± 20 mV), weakly reducing (Eh of 100 ± 20 mV), and moderately reducing (Eh of -100 ± 20 mV) soil conditions for 30 to 31 d. The concentrations of nine pharmaceuticals (bezafibrate, carbamazepine, ciprofloxacin, sulfamethoxazole, trimethoprim, enrofloxacin, clarithromycin, diclofenac, and naproxen) were extracted via solid-phase extraction from soil slurries and analyzed by liquid chromatography-tandem mass spectrometry. Low Eh did not lead to a release of formerly sorbed pharmaceuticals from the wastewater irrigated soil. High pH values (>8) of the examined soil resulting from denitrification under reducing conditions prevented the dissolution of Fe-(hydr)oxides and, hence, the potential release of pharmaceuticals. A trend of decreasing concentrations of sulfamethoxazole and bezafibrate with time under moderately reducing conditions supports previous findings of a transformation of these compounds under anaerobic conditions. PMID:25602209

  9. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Software development for a computer-aided crop and soil survey system is nearing completion. Computer-aided variety classification accuracies using LANDSAT-1 MSS data for a 600 hectare citrus farm were 83% for Redblush grapefruit and 91% for oranges. These accuracies indicate that there is good potential for computer-aided inventories of grapefruit and orange citrus orchards with LANDSAT-type MSS data. Mean digital values of clouds differed statistically from those for crop, soil, and water entities, and those for cloud shadows were enough lower than sunlit crop and soil to be distinguishable. The standard errors of estimate for the calibration of computer compatible tape coordinate system (pixel and record) to earth coordinate system (longitude and latitude) for 6 LANDSAT scenes ranged from 0.72 to 1.50 pixels and from 0.58 to 1.75 records.

  10. Organic phosphorus fractions in organically amended paddy soils in continuously and intermittently flooded conditions.

    PubMed

    Yang, Changming; Yang, Linzhang; Jianhua, Lee

    2006-01-01

    Soil organic phosphorus (SOP) can greatly contribute to plant-available P and P nutrition. The study was conducted to determine the effects of organic amendments on organic P fractions and microbiological activities in paddy soils. Samples were collected at the Changshu Agro-ecological Experiment Station in Tahu Lake Basin, China, from an experiment that has been performed from 1999 to 2004, on a paddy soil (Gleysols). Treatments consisted of swine manure (SM), wheat straw (WS), swine manure plus wheat straw (SM + WS), and a control (chemical fertilization alone). Organic amendments markedly increased soil total organic phosphorus (TOP) and total organic carbon (TOC), especially in continuously flooded conditions. Based on the fractionation of SOP, organic amendments significantly increased soil labile organic phosphorus (LOP), moderately labile organic phosphorus (MLOP), and moderately stable organic phosphorus (MSOP) compared with the control. For SM and SM + WS treatments, LOP in continuously flooded soils decreased by 30.1 and 36.4%, respectively, compared to intermittently flooded soils. In organically amended soils, continuous flooding showed significantly lower microbial biomass phosphorus (MBP) and alkaline phosphatase activities (APA) than intermittent flooding. In intermittently flooded conditions, incorporating organic amendments into soil resulted in greater P uptake and biomass yield of rice than the control. In the intermittently flooded soils, APA (P < 0.05) and MBP (P < 0.01) were significantly and positively related to TOP, LOP, MLOP, and MSOP, whereas in continuously flooded soils, there was a significant (P < 0.05) negative relationship between MBP, TOP, and MSOP. Based on soil organic P fractions and soil enzymatic and microbiological activities, continuous flooding applied to paddy soils should be avoided, especially when swine manure is incorporated into paddy soil. PMID:16738400

  11. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1977-01-01

    The author has identified the following significant results. The best wavelengths in the 0.4 to 2.5 micron interval were determined for detecting lead toxicity and ozone damage, distinguishing succulent from woody species, and detecting silverleaf sunflower. A perpendicular vegetation index, a measure of the distance from the soil background line, in MSS 5 and MSS 7 data space, of pixels containing vegetation was developed and tested as an indicator of vegetation development and crop vigor. A table lookup procedure was devised that permits rapid identification of soil background and green biomass or phenological development in LANDSAT scenes without the need for training data.

  12. Soil-pore water distribution of silver and gold engineered nanoparticles in undisturbed soils under unsaturated conditions.

    PubMed

    Tavares, D S; Rodrigues, S M; Cruz, N; Carvalho, C; Teixeira, T; Carvalho, L; Duarte, A C; Trindade, T; Pereira, E; Römkens, P F A M

    2015-10-01

    Release of engineered nanoparticles (ENPs) to soil is well documented but little is known on the subsequent soil-pore water distribution of ENPs once present in soil. In this study, the availability and mobility of silver (Ag) and gold (Au) ENPs added to agricultural soils were assessed in two separate pot experiments. Pore water samples collected from pots from day 1 to 45 using porous (<0.17 μm) membrane samplers suggest that both Ag and Au are retained almost completely within 24 h with less than 13% of the total added amount present in pore water on day 1. UV-Vis and TEM results showed that AuENPs in pore water were present as both homoaggregates and heteroaggregates until day 3 after which the concentration in pore water was too low to detect the presence of aggregates. A close relation between the concentration of Au and Fe in pore water suggests that the short term solubility of Au is partly controlled by natural soil colloids. Results suggest that under normal aerated soil conditions the actual availability of Ag and AuENPs is low which is relevant in view of risk assessment even though the impact of environmental conditions and soil properties on the reactivity of ENPs (and/or large ENPs aggregates) retained in the solid matrix need to be addressed further. PMID:25965160

  13. Soil-pore water distribution of silver and gold engineered nanoparticles in undisturbed soils under unsaturated conditions.

    PubMed

    Tavares, D S; Rodrigues, S M; Cruz, N; Carvalho, C; Teixeira, T; Carvalho, L; Duarte, A C; Trindade, T; Pereira, E; Römkens, P F A M

    2015-10-01

    Release of engineered nanoparticles (ENPs) to soil is well documented but little is known on the subsequent soil-pore water distribution of ENPs once present in soil. In this study, the availability and mobility of silver (Ag) and gold (Au) ENPs added to agricultural soils were assessed in two separate pot experiments. Pore water samples collected from pots from day 1 to 45 using porous (<0.17 μm) membrane samplers suggest that both Ag and Au are retained almost completely within 24 h with less than 13% of the total added amount present in pore water on day 1. UV-Vis and TEM results showed that AuENPs in pore water were present as both homoaggregates and heteroaggregates until day 3 after which the concentration in pore water was too low to detect the presence of aggregates. A close relation between the concentration of Au and Fe in pore water suggests that the short term solubility of Au is partly controlled by natural soil colloids. Results suggest that under normal aerated soil conditions the actual availability of Ag and AuENPs is low which is relevant in view of risk assessment even though the impact of environmental conditions and soil properties on the reactivity of ENPs (and/or large ENPs aggregates) retained in the solid matrix need to be addressed further.

  14. Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source

    NASA Astrophysics Data System (ADS)

    Balint, Ramona; Said-Pullicino, Daniel; Ajmone-Marsan, Franco

    2015-02-01

    Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behavior of associated metallic elements (MEs). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing its susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behavior of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, was influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination.

  15. Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source.

    PubMed

    Balint, Ramona; Said-Pullicino, Daniel; Ajmone-Marsan, Franco

    2015-02-01

    Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behavior of associated metallic elements (MEs). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing its susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behavior of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, was influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination.

  16. Estimating steady-state evaporation rates from bare soils under conditions of high water table

    USGS Publications Warehouse

    Ripple, C.D.; Rubin, J.; Van Hylckama, T. E. A.

    1970-01-01

    A procedure that combines meteorological and soil equations of water transfer makes it possible to estimate approximately the steady-state evaporation from bare soils under conditions of high water table. Field data required include soil-water retention curves, water table depth and a record of air temperature, air humidity and wind velocity at one elevation. The procedure takes into account the relevant atmospheric factors and the soil's capability to conduct 'water in liquid and vapor forms. It neglects the effects of thermal transfer (except in the vapor case) and of salt accumulation. Homogeneous as well as layered soils can be treated. Results obtained with the method demonstrate how the soil evaporation rates·depend on potential evaporation, water table depth, vapor transfer and certain soil parameters.

  17. Improved Prediction of Quasi-Global Vegetation Conditions Using Remotely-Sensed Surface Soil Moisture

    NASA Technical Reports Server (NTRS)

    Bolten, John; Crow, Wade

    2012-01-01

    The added value of satellite-based surface soil moisture retrievals for agricultural drought monitoring is assessed by calculating the lagged rank correlation between remotely-sensed vegetation indices (VI) and soil moisture estimates obtained both before and after the assimilation of surface soil moisture retrievals derived from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) into a soil water balance model. Higher soil moisture/VI lag correlations imply an enhanced ability to predict future vegetation conditions using estimates of current soil moisture. Results demonstrate that the assimilation of AMSR-E surface soil moisture retrievals substantially improve the performance of a global drought monitoring system - particularly in sparsely-instrumented areas of the world where high-quality rainfall observations are unavailable.

  18. Soil heating and evaporation under extreme conditions: Forest fires and slash pile burns

    NASA Astrophysics Data System (ADS)

    Massman, W. J.

    2011-12-01

    Heating any soil during a sufficiently intense wild fire or prescribed burn can alter soil irreversibly, resulting in many significant and well known, long term biological, chemical, and hydrological effects. To better understand how fire impacts soil, especially considering the increasing probability of wildfires that is being driven by climate change and the increasing use of prescribe burns by land managers, it is important to better understand the dynamics of the coupled heat and moisture transport in soil during these extreme heating events. Furthermore, improving understanding of heat and mass transport during such extreme conditions should also provide insights into the associated transport mechanisms under more normal conditions as well. Here I describe the development of a new model designed to simulate soil heat and moisture transport during fires where the surface heating often ranges between 10,000 and 100,000 Wm-2 for several minutes to several hours. Model performance is tested against laboratory measurements of soil temperature and moisture changes at several depths during controlled heating events created with an extremely intense radiant heater. The laboratory tests employed well described soils with well known physical properties. The model, on the other hand, is somewhat unusual in that it employs formulations for temperature dependencies of the soil specific heat, thermal conductivity, and the water retention curve (relation between soil moisture and soil moisture potential). It also employs a new formulation for the surface evaporation rate as a component of the upper boundary condition, as well as the Newton-Raphson method and the generalized Thomas algorithm for inverting block tri-diagonal matrices to solve for soil temperature and soil moisture potential. Model results show rapid evaporation rates with significant vapor transfer not only to the free atmosphere above the soil, but to lower depths of the soil, where the vapor re

  19. Influence of sea salts on drainage water and soil chemistry of two different soil types: soil leaching experiments under laboratory conditions.

    PubMed

    Sariyildiz, Temel

    2004-07-01

    The effects of sea-salt on drainage water and soil chemistry was studied using two different soil types and setting up five soil-leaching experiments under controlled laboratory conditions. The objectives of the soil-leaching experiments were to provide information of the variability of soils and their drainage water chemistry following the input of different sea-salt solutions with different times which was similar to the precipitation input experienced during the storms in fields. Analyses were presented of major ions (Na+, Ca2+, Mg2+, Cl-, NO3-, SO4(2-) and NH4+) and pH for drainage water. At the end of the experiment, CEC (cation exchange capacity), %BS (percent base saturation), exchangeable capacity of Na, Ca and Mg and pH were also analysed for soil horizon chemistry. The results showed an increase in concentration of most of the major ions in the drainage water, though some adsorption of Na, Ca and Mg had taken place; so the result being a significant decrease in soil water pH. The chemical characteristics of each soil horizons also showed significant changes with the sea-salt applications compared to initial chemical characteristics. However, comparison of data from the four different sea-salt applications under different soil type or land-use didn't indicate the additional role that different land management could play in drainage water or soil chemistry.

  20. Load dissipation by corn residue on tilled soil in laboratory and field-wheeling conditions.

    PubMed

    Reichert, José M; Brandt, André A; Rodrigues, Miriam F; Reinert, Dalvan J; Braida, João A

    2016-06-01

    Crop residues may partially dissipate applied loads and reduce soil compaction. We evaluated the effect of corn residue on energy-applied dissipation during wheeling. The experiment consisted of a preliminary laboratory test and a confirmatory field test on a Paleaudalf soil. In the laboratory, an adapted Proctor test was performed with three energy levels, with and without corn residue. Field treatments consisted of three 5.1 Mg tractor wheeling intensities (0, 2, and 6), with and without 12 Mg ha(-1) corn residue on the soil surface. Corn residue on the soil surface reduced soil bulk density in the adapted Proctor test. By applying energy of 52.6 kN m m(-3) , soil dissipated 2.98% of applied energy, whereas with 175.4 kN m m(-3) a dissipation of 8.60% was obtained. This result confirms the hypothesis that surface mulch absorbs part of the compaction effort. Residue effects on soil compaction observed in the adapted Proctor test was not replicated under subsoiled soil field conditions, because of differences in applied pressure and soil conditions (structure, moisture and volume confinement). Nevertheless, this negative result does not mean that straw has no effect in the field. Such effects should be measured via stress transmission and compared to soil load-bearing capacity, rather than on bulk deformations. Wheeling by heavy tractor on subsoiled soil increased compaction, independently of surface residue. Two wheelings produced a significantly increase, but six wheelings did not further increase compaction. Reduced traffic intensity on recently tilled soil is necessary to minimize soil compaction, since traffic intensity show a greater effect than surface mulch on soil protection from excessive compaction. © 2015 Society of Chemical Industry. PMID:26304050

  1. Characterising soil surface condition and carbon vulnerability using spatial statistics and directional reflectance

    NASA Astrophysics Data System (ADS)

    Croft, H.; Anderson, K.

    2008-12-01

    Soils can experience rapid structural degradation in response to land cover changes, resulting in reduced soil productivity, increased erodibility and a loss of Soil Organic Matter (SOM). The breakdown of soil aggregates through slaking and raindrop impact is linked to soil organic matter turnover, with subsequently eroded material often displaying proportionally more SOM. A reduction in aggregate stability is reflected in a decline in soil surface roughness, indicating that a physical soil structural change can be used to highlight soil vulnerability to SOM loss through mineralisation or erosion. Remotely sensed data can provide a cost- effective means of monitoring changes in soil surface condition over broad spatial extents. Growing recognition of the importance of the directional reflectance domain has highlighted their potential application for monitoring changes in soil surface roughness, associated with the breakdown of macro-aggregates and therefore SOM release. This is particularly relevant for soil condition monitoring because during soil structural degradation, changes in the self-shadowing effects of soil aggregates has a measurable effect on directional reflectance factors measured by proximal remote sensing devices. Field and laboratory data are therefore required for an empirical understanding of soil directional reflectance, underpinning subsequent model development. This experiment details the use of hyperspectral multiple view angle, proximal reflectance data (400-2500 nm) for describing changes in soil surface structure. Five different soil crusting states were produced, simulating a progressive decline in soil surface structure using artificial rainfall. Each stage was characterised using a close-range laser scanning device with a 2 mm spatial sampling methodology. Data were analysed within a geostatistical framework, where variogram analysis quantitatively confirmed the change in soil surface structure during crusting (sill variance = 0

  2. Soil transport parameters of potassium under a tropical saline soil condition using STANMOD

    NASA Astrophysics Data System (ADS)

    Suzanye da Silva Santos, Rafaelly; Honorio de Miranda, Jarbas; Previatello da Silva, Livia

    2015-04-01

    Environmental responsibility and concerning about the final destination of solutes in soil, so more studies allow a better understanding about the solutes behaviour in soil. Potassium is a macronutrient that is required in high concentrations, been an extremely important nutrient for all agricultural crops. It plays essential roles in physiological processes vital for plant growth, from protein synthesis to maintenance of plant water balance, and is available to plants dissolved in soil water while exchangeable K is loosely held on the exchange sites on the surface of clay particles. K will tend to be adsorbed onto the surface of negatively charged soil particles. Potassium uptake is vital for plant growth but in saline soils sodium competes with potassium for uptake across the plasma membrane of plant cells. This can result in high Na+:K+ ratios that reduce plant growth and eventually become toxic. This study aimed to obtain soil transport parameters of potassium in saline soil, such as: pore water velocity in soil (v), retardation factor (R), dispersivity (λ) and dispersion coefficient (D), in a disturbed sandy soil with different concentrations of potassium chlorate solution (KCl), which is one of the most common form of potassium fertilizer. The experiment was carried out using soil samples collected in a depth of 0 to 20 cm, applying potassium chlorate solution containing 28.6, 100, 200 and 500 mg L-1 of K. To obtain transport parameters, the data were adjusted with the software STANMOD. At low concentrations, interaction between potassium and soil occur more efficiently. It was observed that only the breakthrough curve prepared with solution of 500 mg L-1 reached the applied concentration, and the solution of 28.6 mg L-1 overestimated the parameters values. The STANMOD proved to be efficient in obtaining potassium transport parameters; KCl solution to be applied should be greater than 500 mg L-1; solutions with low concentrations tend to overestimate

  3. Enhanced transformation of diphenylarsinic acid in soil under sulfate-reducing conditions.

    PubMed

    Guan, Ling; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2012-11-30

    Diphenylarsinic acid (DPAA) is known to be the major contaminant in soils where diphenylchloroarsine and diphenylcyanoarsine were abandoned after World Wars I and II. In this study, experimental model studies were performed to elucidate key factors regulating the transformation of DPAA under anaerobic soil conditions. The elimination of DPAA in Gleysol soils (Qiqihar and Shindori soils) was more rapid than in Mollisol and Regosol soils (Heihe and Ikarashi soils, respectively) during a 5-week incubation. No clear relationship between decreasing rates of DPAA concentrations and soil Eh values was found. The Ikarashi soil showed the slowest decrease in DPAA concentrations among the four soils, but the transformation of DPAA was notably enhanced by addition of exogenous sulfate together with acetate, cellulose or rice straw. Addition of molybdate, a specific inhibitor of sulfate reduction, resulted in the stagnation of DPAA transformation, suggesting that indigenous sulfate reducers play a role in DPAA transformation under anaerobic conditions. Arsenate, phenylarsonic acid, phenylmethylarsinic acid, diphenylmethylarsine oxide and three unknown compounds were detected as metabolites of DPAA. This is the first study to reveal enhancement of DPAA transformation under sulfate-reducing conditions. PMID:23069334

  4. Bioavailability of freshly added and aged naphthalene in soils under gastric pH conditions

    SciTech Connect

    Jin, Z.; Simkins, S.; Xing, B.

    1999-12-01

    The bioavailability of hydrophobic organic chemicals decreases with aging in soil because of sequestration. However, assessments of the risk of exposure to contaminated soils are usually dependent on either chemical concentrations, which are measured using vigorous extraction methods, or models that assume an equilibrium without considering the actual conditions. The objective of this research was to determine the availability and desorption kinetics of freshly added and aged naphthalene from a peat and a mineral soil; naphthalene was desorbed into solutions with pH levels that approximate those found in different gastric regions. Soil and peat samples were spiked with radiolabeled and unlabeled naphthalene at 2 and 20 {micro}g/g and were aged from 0 to 135 d. Desorption kinetics were determined using a simulated stomach solution and a neutral solution that represented the pH of intestinal conditions and most soils. Peat sorbed much more naphthalene than did soil, and it allowed little desorption. Though both acidic and neutral extracting solutions could desorb naphthalene, little apparent effect of aging was observed in peat, whereas desorption from soil declined markedly with aging. In addition, the percentage of naphthalene that desorbed from soil was greater for the higher incubation concentration. The desorption of naphthalene from the peat and soil was higher into the neutral solution than into the gastric solution. These results suggest that aging, exposure conditions, concentration effect, and organic matter content should be taken into account in predictive models and risk assessments.

  5. Aerobic Dancing--A Rhythmic Sport.

    ERIC Educational Resources Information Center

    Sorensen, Jacki

    Fitness programs now and in the future must offer built-in cardiovascular conditioning, variety, novelty, and change to meet the physical, mental, and emotional needs of our society. Aerobic dancing (dancing designed to train and strengthen the heart, lungs, and vascular system) is one of the first indoor group Aerobic exercise programs designed…

  6. Forest soil respiration rate and delta13C is regulated by recent above ground weather conditions.

    PubMed

    Ekblad, Alf; Boström, Björn; Holm, Anders; Comstedt, Daniel

    2005-03-01

    Soil respiration, a key component of the global carbon cycle, is a major source of uncertainty when estimating terrestrial carbon budgets at ecosystem and higher levels. Rates of soil and root respiration are assumed to be dependent on soil temperature and soil moisture yet these factors often barely explain half the seasonal variation in soil respiration. We here found that soil moisture (range 16.5-27.6% of dry weight) and soil temperature (range 8-17.5 degrees C) together explained 55% of the variance (cross-validated explained variance; Q2) in soil respiration rate (range 1.0-3.4 micromol C m(-2) s(-1)) in a Norway spruce (Picea abies) forest. We hypothesised that this was due to that the two components of soil respiration, root respiration and decomposition, are governed by different factors. We therefore applied PLS (partial least squares regression) multivariate modelling in which we, together with below ground temperature and soil moisture, used the recent above ground air temperature and air humidity (vapour pressure deficit, VPD) conditions as x-variables. We found that air temperature and VPD data collected 1-4 days before respiration measurements explained 86% of the seasonal variation in the rate of soil respiration. The addition of soil moisture and soil temperature to the PLS-models increased the Q2 to 93%. delta13C analysis of soil respiration supported the hypotheses that there was a fast flux of photosynthates to root respiration and a dependence on recent above ground weather conditions. Taken together, our results suggest that shoot activities the preceding 1-6 days influence, to a large degree, the rate of root and soil respiration. We propose this above ground influence on soil respiration to be proportionally largest in the middle of the growing season and in situations when there is large day-to-day shifts in the above ground weather conditions. During such conditions soil temperature may not exert the major control on root respiration. PMID

  7. Stress, deformation and micromorphological aspects of soil freezing under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Jetchick, Elizabeth

    In this thesis, frost heave is viewed as a process resulting from the interactions between thermodynamic conditions, soil environment controls such as texture, stress/deformation conditions and soil microstructure. A series of laboratory experiments was devised to investigate the links between these aspects. Because a limited number of studies exist on the development of internal stresses and strains in freezing soil, the work focussed on obtaining rheological data using conventional soil strain gauges and prototype stress transducers. A fine-grained unstructured silt was placed in a column (30 cm diameter by 100 cm length) and subjected to freezing and freeze-thaw cycles from the top down, lasting up to three months. Heat and water flows, as well as stresses and strains were monitored. The frozen soil was sectioned at the end of four of the experiments to examine the soil fabrics that had developed. From the experimental results, schematic stress and strain curves are proposed. For a single freeze cycle, compressive normal and tensile normal stresses were recorded simultaneously by the measuring devices within the freezing soil profile. Ice lens inception took place when the stress field changed, a condition which occurred either at the frost front level or at the base of the growing ice lens. Negative and positive strains reflected the different stress states that were sustained below and above the freezing front. Negative strains or soil consolidation took place as stresses increased before the passage of the frost line. Negligible soil strains were recorded as maximum soil consolidation was attained, before soil expansion. Distinct positive strain patterns indicating secondary and continuing heave, were recorded simultaneously throughout a thickness of soil, over a range of temperatures. Ice lens growth mostly took place as secondary frost heave, but continuing heave was measured, and the temperature conditions for both types of heave were determined. During

  8. Positive responses of coastal dune plants to soil conditioning by the invasive Lupinus nootkatensis

    NASA Astrophysics Data System (ADS)

    Hanslin, Hans Martin; Kollmann, Johannes

    2016-11-01

    Invasive nitrogen-fixing plants drive vegetation dynamics and may cause irreversible changes in nutrient-limited ecosystems through increased soil resources. We studied how soil conditioning by the invasive alien Lupinus nootkatensis affected the seedling growth of co-occurring native plant species in coastal dunes, and whether responses to lupin-conditioned soil could be explained by fertilisation effects interacting with specific ecological strategies of the native dune species. Seedling performance of dune species was compared in a greenhouse experiment using field-collected soil from within or outside coastal lupin stands. In associated experiments, we quantified the response to nutrient supply of each species and tested how addition of specific nutrients affected growth of the native grass Festuca arundinacea in control and lupin-conditioned soil. We found that lupin-conditioned soil increased seedling biomass in 30 out of 32 native species; the conditioned soil also had a positive effect on seedling biomass of the invasive lupin itself. Increased phosphorus mobilisation by lupins was the major factor driving these positive seedling responses, based both on growth responses to addition of specific elements and analyses of plant available soil nutrients. There were large differences in growth responses to lupin-conditioned soil among species, but they were unrelated to selected autecological indicators or plant strategies. We conclude that Lupinus nootkatensis removes the phosphorus limitation for growth of native plants in coastal dunes, and that it increases cycling of other nutrients, promoting the growth of its own seedlings and a wide range of dune species. Finally, our study indicates that there are no negative soil legacies that prevent re-establishment of native plant species after removal of lupins.

  9. Soil conditions and cereal root system architecture: review and considerations for linking Darwin and Weaver.

    PubMed

    Rich, Sarah M; Watt, Michelle

    2013-03-01

    Charles Darwin founded root system architecture research in 1880 when he described a root bending with gravity. Curving, elongating, and branching are the three cellular processes in roots that underlie root architecture. Together they determine the distribution of roots through soil and time, and hence the plants' access to water and nutrients, and anchorage. Most knowledge of these cellular processes comes from seedlings of the model dicotyledon, Arabidopsis, grown in soil-less conditions with single treatments. Root systems in the field, however, face multiple stimuli that interact with the plant genetics to result in the root system architecture. Here we review how soil conditions influence root system architecture; focusing on cereals. Cereals provide half of human calories, and their root systems differ from those of dicotyledons. We find that few controlled-environment studies combine more than one soil stimulus and, those that do, highlight the complexity of responses. Most studies are conducted on seedling roots; those on adult roots generally show low correlations to seedling studies. Few field studies report root and soil conditions. Until technologies are available to track root architecture in the field, soil analyses combined with knowledge of the effects of factors on elongation and gravitropism could be ranked to better predict the interaction between genetics and environment (G×E) for a given crop. Understanding how soil conditions regulate root architecture can be effectively used to design soil management and plant genetics that best exploit synergies from G×E of roots.

  10. Uranium partitioning under acidic conditions in a sandy soil aquifer

    SciTech Connect

    Johnson, W.H. |; Serkiz, S.M.; Johnson, L.M.

    1995-07-01

    The partitioning of uranium in an aquifer down gradient of two large mixed waste sites was examined with respect to the solution and soil chemistry (e.g., pH redox potential and contaminant concentration) and aqueous-phase chemical speciation. This involved generation of field-derived, batch sorption, and reactive mineral surface sorption data. Field-derived distribution coefficients for uranium at these waste sites were found to vary between 0.40 and 15,000. Based on thermodynamic speciation modeling and a comparison of field and laboratory data, gibbsite is a potential reactive mineral surface present in modified soils at the sites. Uranium partitioning data are presented from field samples and laboratory studies of background soil and the mineral surface gibbsite. Mechanistic and empirical sorption models fit to the field-derived uranium partitioning data show an improvement of over two orders of magnitude, as measured by the normalized sum of errors squared, when compared with the single K{sub d} model used in previous risk work. Models fit to batch sorption data provided a better fit of sorbed uranium than do models fit to the field-derived data.

  11. Breaking The Enzymatic Latch: Do Anaerobic Conditions Constrain Decomposition In Humid Tropical Forest Soil?

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.

    2011-12-01

    Anaerobic conditions have been proposed to impose a "latch" on soil organic matter decomposition by inhibiting the activity of extracellular enzymes that catalyze the transformation of organic polymers into monomers for microbial assimilation. Here, we tested the hypothesis that anaerobiosis inhibits soil hydrolytic enzyme activity in a humid tropical forest ecosystem in Puerto Rico. We sampled surface and sub-surface soil from each of 59 plots (n = 118) stratified across distinct topographical zones (ridges, slopes, and valleys) known to vary in soil oxygen (O2) concentrations, and measured the potential activity of five hydrolytic enzymes that decompose carbon (C), nitrogen (N), and phosphorus (P) substrates. We measured reduced iron (Fe (II)) concentrations in soil extractions to provide a spatially and temporally integrated index of anaerobic microbial activity, since iron oxides constitute the dominant anaerobic terminal electron acceptor in this ecosystem. Surprisingly, we observed positive relationships between Fe (II) concentrations and the activity of all enzymes that we assayed. Linear mixed effects models that included Fe (II) concentration, topographic position, and their interaction explained between 30 to 70 % of the variance of enzyme activity of β-1,4-glucosidase, β-cellobiohydrolase, β-xylosidase, N-acetylglucosaminidase, and acid phosphatase. Soils from ridges and slopes contained between 10 and 800 μg Fe (II) g-1 soil, and exhibited consistently positive relationships (p < 0.0001) between Fe (II) and enzyme activity. Valley soils did not display significant relationships between enzyme activity and Fe (II), although they displayed variation in soil Fe (II) concentrations similar to ridges and slopes. Overall, valleys exhibited lower enzyme activity and lower Fe (II) concentrations than ridges or slopes, possibly related to decreased root biomass and soil C. Our data provide no indication that anaerobiosis suppresses soil enzyme activity, but

  12. Volatile chemical spoilage indexes of raw Atlantic salmon (Salmo salar) stored under aerobic condition in relation to microbiological and sensory shelf lives.

    PubMed

    Mikš-Krajnik, Marta; Yoon, Yong-Jin; Ukuku, Dike O; Yuk, Hyun-Gyun

    2016-02-01

    The purpose of this investigation was to identify and quantify the volatile chemical spoilage indexes (CSIs) for raw Atlantic salmon (Salmo salar) fillets stored under aerobic storage conditions at 4, 10 and 21 °C in relation to microbial and sensory shelf lives. The volatile organic compounds (VOCs) were analyzed with SPME-GC-MS technique. Through multivariate chemometric method, hierarchical cluster analysis (HCA) and Pearson's correlations, the CSIs: trimethylamine (TMA), ethanol (EtOH), 3-methyl-1-butanol (3Met-1But), acetoin and acetic acid (C2) were selected from the group of 28 detected VOCs. At the moment of microbiological shelf life established at total viable count (TVC) of 7.0 log CFU/g, the CSIs achieved levels of 11.5, 38.3, 0.3, 24.0 and 90.7 μg/g of salmon for TMA, EtOH, 3M-1But, acetoin and C2, respectively. Pseudomonas spp. was found as major specific spoilage organism (SSOs), suitable for shelf life prediction using modified Gompertz model at the cut-off level of 6.5 log CFU/g. H2S producing bacteria and Brochothrix thermosphacta were considered as important spoilage microorganisms; however, they were not suitable for shelf life estimation. Partial least square (PLS) regression revealed possible associations between microorganisms and synthetized VOCs, showing correlations between Pseudomonas spp. and 3Met-1But and aldehydes synthesis, lactic acid bacteria were linked with EtOH, C2 and esters, and B. thermosphacta with acetoin formation. PMID:26678146

  13. Volatile chemical spoilage indexes of raw Atlantic salmon (Salmo salar) stored under aerobic condition in relation to microbiological and sensory shelf lives.

    PubMed

    Mikš-Krajnik, Marta; Yoon, Yong-Jin; Ukuku, Dike O; Yuk, Hyun-Gyun

    2016-02-01

    The purpose of this investigation was to identify and quantify the volatile chemical spoilage indexes (CSIs) for raw Atlantic salmon (Salmo salar) fillets stored under aerobic storage conditions at 4, 10 and 21 °C in relation to microbial and sensory shelf lives. The volatile organic compounds (VOCs) were analyzed with SPME-GC-MS technique. Through multivariate chemometric method, hierarchical cluster analysis (HCA) and Pearson's correlations, the CSIs: trimethylamine (TMA), ethanol (EtOH), 3-methyl-1-butanol (3Met-1But), acetoin and acetic acid (C2) were selected from the group of 28 detected VOCs. At the moment of microbiological shelf life established at total viable count (TVC) of 7.0 log CFU/g, the CSIs achieved levels of 11.5, 38.3, 0.3, 24.0 and 90.7 μg/g of salmon for TMA, EtOH, 3M-1But, acetoin and C2, respectively. Pseudomonas spp. was found as major specific spoilage organism (SSOs), suitable for shelf life prediction using modified Gompertz model at the cut-off level of 6.5 log CFU/g. H2S producing bacteria and Brochothrix thermosphacta were considered as important spoilage microorganisms; however, they were not suitable for shelf life estimation. Partial least square (PLS) regression revealed possible associations between microorganisms and synthetized VOCs, showing correlations between Pseudomonas spp. and 3Met-1But and aldehydes synthesis, lactic acid bacteria were linked with EtOH, C2 and esters, and B. thermosphacta with acetoin formation.

  14. An analysis of the dissipation of pharmaceuticals under thirteen different soil conditions.

    PubMed

    Kodešová, Radka; Kočárek, Martin; Klement, Aleš; Golovko, Oksana; Koba, Olga; Fér, Miroslav; Nikodem, Antonín; Vondráčková, Lenka; Jakšík, Ondřej; Grabic, Roman

    2016-02-15

    The presence of human and veterinary pharmaceuticals in the environment is recognized as a potential threat. Pharmaceuticals have the potential to contaminate soils and consequently surface and groundwater. Knowledge of contaminant behavior (e.g., sorption onto soil particles and degradation) is essential when assessing contaminant migration in the soil and groundwater environment. We evaluated the dissipation half-lives of 7 pharmaceuticals in 13 soils. The data were evaluated relative to the soil properties and the Freundlich sorption coefficients reported in our previous study. Of the tested pharmaceuticals, carbamazepine had the greatest persistence (which was mostly stable), followed by clarithromycin, trimethoprim, metoprolol, clindamycin, sulfamethoxazole and atenolol. Pharmaceutical persistence in soils was mostly dependent on the soil-type conditions. In general, lower average dissipation half-lives and variability (i.e., trimethoprim, sulfamethoxazole, clindamycin, metoprolol and atenolol) were found in soils of better quality (well-developed structure, high nutrition content etc.), and thus, probably better microbial conditions (i.e., Chernozems), than in lower quality soil (Cambisols). The impact of the compound sorption affinity onto soil particles on their dissipation rate was mostly negligible. Although there was a positive correlation between compound dissipation half-life and Freundlich sorption coefficient for clindamycin (R=0.604, p<0.05) and sulfamethoxazole (R=0.822, p<0.01), the half-life of sulfamethoxazole also decreased under better soil-type conditions. Based on the calculated dissipation and sorption data, carbamazepine would be expected to have the greatest potential to migrate in the soil water environment, followed by sulfamethoxazole, trimethoprim and metoprolol. The transport of clindamycin, clarithromycin and atenolol through the vadose zone seems less probable.

  15. Degradation of 4,5-dichloroguaiacol by soil microorganisms.

    PubMed

    González, B; Brezny, R; Herrera, M; Joyce, T W

    1995-09-01

    No microorganisms could be isolated from chemostats or from a soil column fed with 4,5-dichloroguaiacol as the only carbon source. If guaiacol was added to chemostats with 4,5-dichloroguaiacol, either soil microbial consortia or guaiacol-degrading bacteria could dechlorinate the 4,5-dichloroguaiacol provided it was <0.2MM. A microbial consortium from farm soil removed 4,5-dichloroguaiacol under aerobic or anoxic conditions, with or without chlorolignin. Dichlorocatechol was the only 4,5-dichloroguaiacol-derived metabolite detected. In aerobic incubations, 4,5-dichlorocatechol was further degraded whereas under anoxic conditions it accumulated. PMID:24414909

  16. Manganese-oxide-coated redox bars as an indicator of reducing conditions in soils.

    PubMed

    Dorau, Kristof; Mansfeldt, Tim

    2015-03-01

    Identification of reducing conditions in soils is of concern not only for pedogenesis but also for nutrient and pollutant dynamics. We manufactured manganese (Mn)-oxide-coated polyvinyl chloride bars and proved their suitability for the identification of reducing soil conditions. Birnessite was synthesized and coated onto white polyvinyl chloride bars. The dark brown coatings were homogenous and durable. As revealed by microcosm devices with adjusted redox potentials (E), under oxidizing conditions (E ∼450 mV at pH 7) there was no Mn-oxide removal. Reductive dissolution of Mn-oxides, which is expressed by the removal of the coatings, started under weakly reducing conditions (E ∼175 mV) and was more intensive under moderately reducing conditions (∼80 mV). According to thermodynamics, the removal of Mn-oxide coatings (225 mm d) exceeded the removal of iron (Fe)-oxide coatings (118 mm d) in soil column experiments. This was confirmed in a soil with a shallow and strongly fluctuating water table where both types of redox bars were inserted. Consequently, it was possible to identify reducing conditions in soils using Mn-oxide-coated bars. We recommend this methodology for short-term monitoring because tri- and tetravalent Mn is the preferred electron acceptor compared with trivalent Fe, and this additionally offers the possibility of distinguishing between weakly and moderately reducing conditions. If dissolved Fe is abundant in soils, the possibility of nonenzymatic reduction of Mn has to be taken into account.

  17. Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil

    NASA Astrophysics Data System (ADS)

    Won, Jongho; Borden, Robert C.

    2016-11-01

    Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate > 200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20 g/m3/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil.

  18. Changes in mineral soil biogeochemical cycling and environmental conditions following tree harvest in the Northeast

    NASA Astrophysics Data System (ADS)

    Vario, C.; Friedland, A.

    2012-12-01

    In the northeastern United States, reductions in carbon dioxide emissions have been attempted by using local wood as a renewable alternative to oil. Although woody biomass products are readily available, recent findings suggest that forest disturbance may cause release of carbon from the deeper mineral soil. Worldwide, deep soils sequester more than half of soil carbon, making it critical in the global carbon cycle; however, most studies on the effect of harvesting have focused on the organic soil horizon. Our research aimed to uncover changes in biogeochemistry and environmental conditions in deeper, mineral soil after clear cutting forests. We quantified post-harvest mineral soil carbon pools through a regional study. We utilized stands of different ages to measure the recovery of soil carbon over time since harvest. Stands included in this study were cut approximately 5, 12, 25, 50, or 120 ybp, in order to identify changes in soil carbon over time since harvest. We sampled harvested stands in six research or protected forests across New York, New Hampshire, Massachusetts, and Vermont. Soil samples were collected to a depth of 60 cm below the surface of the mineral soil using a gas-powered augur and 9.5 cm diameter drill bit. Soil samples were analyzed at Dartmouth College. In order to understand specific changes in mineral soil carbon dynamics following harvest, measurements of carbon fluxes, such as soil respiration and DOC transport were conducted at five different-aged stands at Bartlett Experimental Forest, NH. While parameters that may influence carbon storage—such as pH, clay content, tree cover and elevation— did not vary across the different-aged stands in each forest, carbon pools did vary over time. We found changes in carbon pools in at least three experimental forests across the northeast. At Bartlett Experimental Forest, we found a gradual decline in mineral soil carbon storage from between 85-87 Mg ha-1 in 120 year old and primary forest stands

  19. Differential sensitivity of aerobic gram-positive and gram-negative microorganisms to 2,4,6-trinitrotoluene (TNT) leads to dissimilar growth and TNT transformation: Results of soil and pure culture studies

    SciTech Connect

    Fuller, M.E.; Manning, J.F. Jr.

    1996-07-30

    The effects of 2,4,6-trinitrotoluene (TNT) on indigenous soil populations and pure bacterial cultures were examined. The number of colony-forming units (CFU) appearing when TNT-contaminated soil was spread on 0.3% molasses plates decreased by 50% when the agar was amended with 67 {mu}g TNT mL{sup -1}, whereas a 99% reduction was observed when uncontaminated soil was plated. Furthermore, TNT-contaminated soil harbored a greater number of organisms able to grow on plates amended with greater than 10 {mu}g TNT mL{sup -1}. The percentage of gram-positive isolates was markedly less in TNT-contaminated soil (7%; 2 of 30) than in uncontaminated soil (61%; 20 of 33). Pseudomonas aeruginosa, Pseudomonas corrugate, Pseudomonasfluorescens and Alcaligenes xylosoxidans made up the majority of the gram-negative isolates from TNT-contaminated soil. Gram-positive isolates from both soils demonstrated marked growth inhibition when greater than 8-16 {mu}g TNT mL{sup -1} was present in the culture media. Most pure cultures of known aerobic gram-negative organisms readily degraded TNT and evidenced net consumption of reduced metabolites. However, pure cultures of aerobic gram-positive bacteria were sensitive to relatively low concentrations of TNT as indicated by the 50% reduction in growth and TNT transformation which was observed at approximately 10 {mu}g TNT mL{sup -1}. Most non-sporeforming gram-positive organisms incubated in molasses media amended with 80 {mu}g TNT mL{sup -1} or greater became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 {mu}g TNT mL{sup -1}, indicating that TNT sensitivity is likely linked to cell growth. These results indicate that gram-negative organisms are most likely responsible for any TNT transformation in contaminated soil, due to their relative insensitivity to high TNT concentrations and their ability to transform TNT.

  20. Soil nitrous oxide emissions under climate change in Mediterranean dryland conditions

    NASA Astrophysics Data System (ADS)

    Álvaro-Fuentes, Jorge; Arrúe, José Luis; Plaza-Bonilla, Daniel; Cantero-Martínez, Carlos

    2016-04-01

    Soils play a double role in relation with climate change. Soils have the ability to decrease atmospheric carbon dioxide concentration throughout soil carbon sequestration and, concurrently, they are also a main source of greenhouse gases. Particularly, agricultural soils are major emitters of nitrous oxide (N2O) globally. Recent outputs from general circulation models show that in the near future drought stress would be especially critical in the Mediterranean basin. These predictions could have a noteworthy impact on soil N2O emissions. Consequently, current mitigation options might be no longer valid in the near future. The main objective of this work was to determine the capability of different land uses under climate change conditions to mitigate soil N2O emissions in Mediterranean dryland agroecosystems. Soil N2O emissions were measured during 18 months (from December 2011 to June 2013) under different land uses in a typical Mediterranean agroecosystem. The observed data was used to test the ability of the Daycent model to simulate N2O emissions in dryland Mediterranean soils. Next, the model was used to predict the impact of climate change on soil N2O emissions under different land use scenarios in Mediterranean conditions.

  1. Butachlor inhibits production and oxidation of methane in tropical rice soils under flooded condition.

    PubMed

    Mohanty, S R; Nayak, D R; Babu, Y J; Adhya, T K

    2004-01-01

    In laboratory incubation experiments, application of a commercial formulation of the herbicide butachlor (N-butoxymethyl-2-chloro-2',6'-diethyl acetanilide) to three tropical rice soils, widely differing in their physicochemical characteristics, under flooded condition inhibited methane (CH4) production. The inhibitory effect was concentration dependent and most remarkable in the alluvial soil. Thus, following application of butachlor at 5, 10, 50 and 100 microg g(-1) soil, respectively, cumulative CH4 production in the alluvial soil was inhibited by 15%, 31%, 91% and 98% over unamended control. Since CH4 production was less pronounced in the sandy loam and acid sulfate soil, the impact of amendment with butchalor, albeit inhibitory, was less extensive than the alluvial soil. Inhibition of CH4 production in butachlor-amended alluvial soil was related to the prevention in the drop in redox potential as well as low methanogenic bacterial population especially at high concentrations of butachlor. CH4 oxidation was also inhibited in butachlor-amended alluvial soil with the inhibitory effect being more prevalent under flooded condition. Inhibition in CH4 oxidation was related to a reduction in the population of soluble methane monooxygenase producing methanotrophs. Results demonstrate that butachlor, a commonly used herbicide in rice cultivation, even at very low concentrations can affect CH4 production and its oxidation, thereby influencing the biogeochemical cycle of CH4 in flooded rice soils.

  2. Soil, Water, and Vegetation Conditions in South Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Reflectance differences between the dead leaves of six crops (corn, cotton, sorghum, sugar cane, citrus, and avocado) and the respective bare soils where the dead leaves were lying on the ground were determined from laboratory spectrophotometric measurements over the 0.5- to 2.5 micron wavelength interval. The largest differences were in the near infrared waveband 0.75- to 1.35 microns. Leaf area index was predicted from plant height, percent ground cover, and plant population for irrigated and nonirrigated grain sorghum fields for the 1975 growing season.

  3. Sensitivity of Polygonum aviculare Seeds to Light as Affected by Soil Moisture Conditions

    PubMed Central

    Batlla, Diego; Nicoletta, Marcelo; Benech-Arnold, Roberto

    2007-01-01

    Background and Aims It has been hypothesized that soil moisture conditions could affect the dormancy status of buried weed seeds, and, consequently, their sensitivity to light stimuli. In this study, an investigation is made of the effect of different soil moisture conditions during cold-induced dormancy loss on changes in the sensitivity of Polygonum aviculare seeds to light. Methods Seeds buried in pots were stored under different constant and fluctuating soil moisture environments at dormancy-releasing temperatures. Seeds were exhumed at regular intervals during storage and were exposed to different light treatments. Changes in the germination response of seeds to light treatments during storage under the different moisture environments were compared in order to determine the effect of soil moisture on the sensitivity to light of P. aviculare seeds. Key Results Seed acquisition of low-fluence responses during dormancy release was not affected by either soil moisture fluctuations or different constant soil moisture contents. On the contrary, different soil moisture environments affected seed acquisition of very low fluence responses and the capacity of seeds to germinate in the dark. Conclusions The results indicate that under field conditions, the sensitivity to light of buried weed seeds could be affected by the soil moisture environment experienced during the dormancy release season, and this could affect their emergence pattern. PMID:17430979

  4. Bioactivity of Several Herbicides on the Nanogram Level Under Different Soil Moisture Conditions.

    PubMed

    Jung, S C; Kuk, Y I; Senseman, S A; Ahn, H G; Seong, C N; Lee, D J

    2015-01-01

    In this study, a double-tube centrifuge method was employed to determine the effects of soil moisture on the bioactivity of cafenstrole, pretilachlor, benfuresate, oxyfluorfen and simetryn. In general, the available herbicide concentration in soil solution (ACSS) showed little change as soil moisture increased for herbicides. The total available herbicide in soil solution (TASS) typically increased as soil moisture increased for all herbicides. The relationship between TASS and % growth rate based on dry weight showed strong linear relationships for both cafenstrole and pretilachlor, with r2 values of 0.95 and 0.84, respectively. Increasing TASS values were consistent with increasing herbicide water solubility, with the exception of the ionizable herbicide simetryn. Plant absorption and % growth rate exhibited a strong linear relationship with TASS. According to the results suggested that TASS was a better predictor of herbicidal bioactivity than ACSS for all herbicides under unsaturated soil moisture conditions. PMID:26328425

  5. Bioactivity of Several Herbicides on the Nanogram Level Under Different Soil Moisture Conditions.

    PubMed

    Jung, S C; Kuk, Y I; Senseman, S A; Ahn, H G; Seong, C N; Lee, D J

    2015-01-01

    In this study, a double-tube centrifuge method was employed to determine the effects of soil moisture on the bioactivity of cafenstrole, pretilachlor, benfuresate, oxyfluorfen and simetryn. In general, the available herbicide concentration in soil solution (ACSS) showed little change as soil moisture increased for herbicides. The total available herbicide in soil solution (TASS) typically increased as soil moisture increased for all herbicides. The relationship between TASS and % growth rate based on dry weight showed strong linear relationships for both cafenstrole and pretilachlor, with r2 values of 0.95 and 0.84, respectively. Increasing TASS values were consistent with increasing herbicide water solubility, with the exception of the ionizable herbicide simetryn. Plant absorption and % growth rate exhibited a strong linear relationship with TASS. According to the results suggested that TASS was a better predictor of herbicidal bioactivity than ACSS for all herbicides under unsaturated soil moisture conditions.

  6. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  7. Effect of soil surface conditions on runoff velocity and sediment mean aggregate diameter

    NASA Astrophysics Data System (ADS)

    César Ramos, Júlio; Bertol, Ildegardis; Paz González, Antonio; de Souza Werner, Romeu; Marioti, Juliana; Henrique Bandeira, Douglas; Andrighetti Leolatto, Lidiane

    2013-04-01

    Soil cover and soil management are the factors that most influence soil erosion by water, because they directly affect soil surface roughness and surface cover. The main effect of soil cover by crop residues consists in dissipation of kinetic energy of raindrops and also partly kinetic energy of runoff, so that the soil disaggregation is considerably reduced but, in addition, soil cover captures detached soil particles, retains water on its surface and decreases runoff volume and velocity. In turn, soil surface roughness, influences soil surface water storage and infiltration and also runoff volume and velocity, sediment retention and subsequently water and sediment losses. Based on the above rationale, we performed a field experiment to assess the influence of soil cover and soil surface roughness on decay of runoff velocity as well as on mean diameter of transported sediments (D50 index). The following treatments were evaluated: SRR) residues of Italian ryegrass (Lolium multiflorum) on a smooth soil surfcace, SRV) residues of common vetch (Vicia sativa) on a smooth soil surface, SSR) scarification after cultivation of Italian ryegrass resulting in a rough surface, SSV) scarification after cultivation of common vetch resulting in a rough surface, and SBS) scarified bare soil with high roughness as a control. The field experiments was performed on an Inceptisol in South Brazil under simulated rainfall conditions during 2012. Experimental plots were 11 m long and 3.5 m wide with an area of 38.5 m2. Six successive simulated rainfall tests were applied using a rotating-boom rain simulator. During each test, rain intensity was 60 mmhr-1, whereas rain duration was 90 minutes. Runoff velocity showed no significant differences between cultivated treatments. However, when compared to bare soil treatment, SBS (0.178 m s-1) and irrespective of the presence of surface crop residues or scarification operations, cultivated soil treatments significantly reduced runoff velocity

  8. The soil ecotoxicology of 1,3-dichloropropene under commercial growing conditions.

    PubMed

    Small, Graham; Miles, Mark; Barber, Ian; Tsakonas, Paris; Bucchi, Renzo

    2008-01-01

    Soil fumigants are used extensively in the protection of crops against parasitic nematodes and other soil borne pests. The active ingredient in Telone II soil fumigant is 1,3-Dichloropropene (1,3-D) which has a wide range of uses in Europe as a pre-plant nematocide. During the use of soil fumigants such as 1,3-D a range of non-target soil dwelling organisms has the potential to be exposed and impacted. We report here the results of a field study conducted in Italy to assess the impact of 1,3-D applications to soil-dwelling non-target organisms. This study was conducted under conditions of commercial tomato growing either without (untreated control) or with an application of 1,3-D at 224 kg a.i./hectare. Samples of arthropods and earthworms were taken before and up to 12 months after application to measure season long effects. A soil sample was taken at 4.5 months and a soil function test performed. By evaluating the effects of 1,3-D both in the Laboratory and under field conditions equivalent to commercial practices it was concluded that applications of 1,3-D would not adversely effect soil arthropods, but may have an effect on earthworms and soil microflora. These effects were, however, transient as full recovery was observed within six months of application for earthworms and 4.5 months for soil microflora. Consequently, the risk to non-target soil micro- and macro-organisms was considered acceptable according to current risk assessment guidelines within the European Union.

  9. Effect of the irrigation with waste water on two different mediterranean soils under greenhouse conditions

    NASA Astrophysics Data System (ADS)

    Pina, S.; Garcia-Orenes, F.; Mataix, J.; Jordan, M. M.; Mataix-Solera, J.

    2009-04-01

    The semi-arid zones as the Mediterranean coast are densely populated and their aquifers are being hardly exploited. The use of waste water for irrigation is an alternative for the water shortage. Consequently, it is considered necessary to improve the efforts to investigate changes of soil properties. The main objective of this work was to compare the short-term effects of irrigation with waste water on two different Mediterranean soils. It was used flowerpots with loquat (Eriobotrya japonica Lindl) under greenhouse conditions. Two different Mediterranean soils were selected from Alicante, SE of Spain, one gypsiferous soil and one calcareous soil with similar texture, to evaluate the different behaviour against waste water irrigation. The flowerpots were irrigated with two different treatments: fresh water (control) and treated waste water from secondary treatment. The experience lasted twelve months, the first six to adapt the plants into the greenhouse and then the soils were irrigated twice a week. Two soil sampling were taking in the beginning and in the end of the experiment to determinate EC, Na, P, OC and N. In both soils our results show a slight increase in electrical conductivity, being deeper in the calcareous soil as it is easier to drain. However it was found a higher increase of sodium concentrations in the gypsiferous soil. Fertility analysis in the secondary treatment of both soils presented an improvement in potassium and available phosphorus levels. In the other hand, organic carbon and nitrogen do not seem to change; the reason could be an enhancement in biological activity caused by irrigation. This biological activity and greenhouse conditions speed up organic matter mineralization. According to the short-term results in the soils studied parameters, except for electrical conductivity and sodium content, there is not a notable negative impact. Nevertheless, it must be necessary to extend the experience for long-term conclusions.

  10. Sensitivity of soil moisture initialization for decadal predictions under different regional climatic conditions in Europe

    NASA Astrophysics Data System (ADS)

    Khodayar, S.; Sehlinger, A.; Feldmann, H.; Kottmeier, C.

    2015-12-01

    The impact of soil initialization is investigated through perturbation simulations with the regional climate model COSMO-CLM. The focus of the investigation is to assess the sensitivity of simulated extreme periods, dry and wet, to soil moisture initialization in different climatic regions over Europe and to establish the necessary spin up time within the framework of decadal predictions for these regions. Sensitivity experiments consisted of a reference simulation from 1968 to 1999 and 5 simulations from 1972 to 1983. The Effective Drought Index (EDI) is used to select and quantify drought status in the reference run to establish the simulation time period for the sensitivity experiments. Different soil initialization procedures are investigated. The sensitivity of the decadal predictions to soil moisture initial conditions is investigated through the analysis of water cycle components' (WCC) variability. In an episodic time scale the local effects of soil moisture on the boundary-layer and the propagated effects on the large-scale dynamics are analysed. The results show: (a) COSMO-CLM reproduces the observed features of the drought index. (b) Soil moisture initialization exerts a relevant impact on WCC, e.g., precipitation distribution and intensity. (c) Regional characteristics strongly impact the response of the WCC. Precipitation and evapotranspiration deviations are larger for humid regions. (d) The initial soil conditions (wet/dry), the regional characteristics (humid/dry) and the annual period (wet/dry) play a key role in the time that soil needs to restore quasi-equilibrium and the impact on the atmospheric conditions. Humid areas, and for all regions, a humid initialization, exhibit shorter spin up times, also soil reacts more sensitive when initialised during dry periods. (e) The initial soil perturbation may markedly modify atmospheric pressure field, wind circulation systems and atmospheric water vapour distribution affecting atmospheric stability

  11. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  12. Influences of solution chemical conditions on mobilization of TNT from contaminated soil

    SciTech Connect

    Dante, D.A.; Tiller, C.L.; Pennell, K.D.

    1996-12-31

    2,4,6-trinitrotoluene (TNT) and its byproducts are common contaminants on US military installations. Many potential remediation processes are in part limited by the transfer of TNT from the contaminated soil into the aqueous phase. The purpose of this research is to assess the release of TNT from contaminated soil under varying solution chemical conditions. In particular, influences of pH, aquatic natural organic matter, and addition of two surfactants is investigated. Uncontaminated soil was collected from a near-surface site at the Alabama Army Ammunition Plant and was artificially contaminated with TNT prior to the mobilization experiments. Results for the pH experiments show that more TNT is mobilized at neutral pH conditions than at low pH conditions. The presence of dissolved organic matter enhances the release of TNT from soil, but not by a large amount. Surfactant addition has the most significant effect on TNT mobilization.

  13. Soil, water, and vegetation conditions in south Texas

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Field spectral measurements and laboratory densitometric measurements showed that tree canopy reflectance differences among the Marrs, Redblush, and Valencia varieties in the visible spectral region were due to their different leaf chlorophyll concentrations. Field measurements of visible light reflectance were directly related to the tonal responses on infrared color photos of the varietal tree canopies. Consequently, densitometric measurements of the foliage on the infrared color transparency with red-filtered light successfully discriminated among the three varieties. Reflectance measurements with a field spectroradiometer on nine dates the growing season of two wheat varieties, Milam and Penjamo, documented their spectra over the 0.45 to 2.50 micron wavelength interval associated with plant cover and physiological development. An image analyzer system was used to optically planimeter the percentage of soil background, vegetation and shadow in the vertical photographs taken within the FOV of the spectroradiometer on each measurement date.

  14. Use of exogenous specialized bacteria in the biological detoxification of a dump site-polychlorobiphenyl-contaminated soil in slurry phase conditions

    SciTech Connect

    Fava, F.; Bertin, L. . Dept. of Applied Chemistry and Material Science)

    1999-07-20

    The possibility of biologically detoxifying a contaminated soil from an Italian dump site containing about 1500 mg/kg (in dry soil) of polychlorinated biphenyls was studied in the laboratory in this work. The soil, which contained indigenous aerobic bacteria capable of growing on biphenyl or on monochlorobenzoic acids at concentration of about 300 CFU per g of air-dried soil, was amended with inorganic nutrients, saturated with water and treated in aerobic 3-L batch slurry reactors (soil suspension at 20% w/v). Either Pseudomonas sp. CPE1 strain, capable of cometabolizing low-chlorinated biphenyls into chlorobenzoic acids, or a bacterial coculture capable of aerobically dechlorinating polychlorobiphenyls constituted by this bacterium and the two chlorobenzoic acid degrading bacteria Pseudomonas sp. CPE2 strain and Alcaligenes sp. CPE3 strain, were used as inocula, in the absence and in the presence of biphenyl (4 g/kg of air dried soil). Significant soil polychlorobiphenyl depletions were observed in all the reactors after 119 days of treatment. The soil inoculation with the sole CPE1 was found to slightly enhance the polychlorobiphenyl depletions (about 20%) and the soil detoxification; the effect was higher in the presence of biphenyl.

  15. Assessment of possibilities and conditions of irrigation in Hungary by digital soil map products

    NASA Astrophysics Data System (ADS)

    Laborczi, Annamária; Bakacsi, Zsófia; Takács, Katalin; Szatmári, Gábor; Szabó, József; Pásztor, László

    2016-04-01

    Sustaining proper soil moisture is essentially important in agricultural management. However, irrigation can be really worth only, if we lay sufficient emphasis on soil conservation. Nationwide planning of irrigation can be taken place, if we have spatially exhaustive maps and recommendations for the different areas. Soil moisture in the pores originate from 'above' (precipitation), or from 'beneath' (from groundwater by capillary lift). The level of groundwater depends on topography, climatic conditions and water regime of the nearby river. The thickness of capillary zone is basicly related to the physical and water management properties of the soil. Accordingly the capillary rise of sandy soils - with very high infiltration rate and very poor water retaining capacity - are far smaller than in the case of clay soils - with very poor infiltration rate and high water retaining capacity. Applying irrigation water can be considered as a reinforcement from 'above', and it affects the salinity and sodicity as well as the soil structure, nutrient supply and soil formation. We defined the possibilities of irrigation according to the average salt content of the soil profile. The nationwide mapping of soil salinity was based on legacy soil profile data, and it was carried out by regression kriging. This method allows that environmental factors with exhaustive spatial extension, such as climatic-, vegetation-, topographic-, soil- and geologic layers can be taken into consideration to the spatial extension of the reference data. According to soil salinity content categories, the areas were delineated as 1. to be irrigated, 2. to be irrigated conditionally, 3. not to be irrigated. The conditions of irrigation was determined by the comparison of the 'actual' and the 'critical' depth of the water table. Since, if the water rises above the critical level, undesirable processes, such as salinization and alkalinization can be developed. The critical depth of the water table was

  16. Modeling soil heating and moisture transport under extreme conditions: Forest fires and slash pile burns

    NASA Astrophysics Data System (ADS)

    Massman, W. J.

    2012-10-01

    Heating any soil during a sufficiently intense wildfire or prescribed burn can alter it irreversibly, causing many significant, long-term biological, chemical, and hydrological effects. Given the climate-change-driven increasing probability of wildfires and the increasing use of prescribed burns by land managers, it is important to better understand the dynamics of the coupled heat and moisture transport in soil during these extreme heating events. Furthermore, improved understanding and modeling of heat and mass transport during extreme conditions should provide insights into the associated transport mechanisms under more normal conditions. The present study describes a numerical model developed to simulate soil heat and moisture transport during fires where the surface heating often ranges between 10,000 and 100,000 W m-2 for several minutes to several hours. Basically, the model extends methods commonly used to model coupled heat flow and moisture evaporation at ambient conditions into regions of extreme dryness and heat. But it also incorporates some infrequently used formulations for temperature dependencies of the soil specific heat, thermal conductivity, and the water retention curve, as well as advective effects due to the large changes in volume that occur when liquid water is rapidly volatilized. Model performance is tested against laboratory measurements of soil temperature and moisture changes at several depths during controlled heating events. Qualitatively, the model agrees with the laboratory observations, namely, it simulates an increase in soil moisture ahead of the drying front (due to the condensation of evaporated soil water at the front) and a hiatus in the soil temperature rise during the strongly evaporative stage of the soil drying. Nevertheless, it is shown that the model is incapable of producing a physically realistic solution because it does not (and, in fact, cannot) represent the relationship between soil water potential and soil

  17. Soil genotoxicity induced by successive applications of chlorothalonil under greenhouse conditions.

    PubMed

    Jin, Xiangxiang; Cui, Ning; Zhou, Wei; Khorram, Mahdi Safaei; Wang, Donghong; Yu, Yunlong

    2014-05-01

    Greenhouse production of vegetables has been developed rapidly in China. High temperature and humidity inside the greenhouse make this environment more suitable for fast reproduction of fungal diseases. Fungicides are among the chemicals used extensively in the greenhouse to prevent crops from invasive infections by phytopathogens; however, little is known about the accumulation of fungicides in soil and their effect on soil quality under greenhouse conditions. In the present study, the accumulation of the fungicide chlorothalonil (CT) and its toxic metabolite hydroxy-chlorothalonil (HCT) in soil as well as their related soil genotoxicity under greenhouse conditions was investigated. The results indicated that both CT and HCT accumulated in soil with repeated applications of CT, and the accumulation level was strongly correlated to application dosage and its frequency. In addition, soil genotoxicity, which was measured by Vicia faba, also increased with the accumulation of CT and HCT, and the main contributor to this phenomenon was CT rather than HCT. The data demonstrated that successive applications of fungicides may result in their accumulation in soil and thus a decline in soil quality.

  18. Soil metabolism of a new herbicide, [14C]Pyribenzoxim, under flooded conditions.

    PubMed

    Chang, Hee-Ra; Koo, Suk-Jin; Kim, Kyun; Ro, Hee-Myong; Moon, Joon-Kwan; Kim, Yong-Hwa; Kim, Jeong-Han

    2007-07-25

    To elucidate the fate of a new pyrimidinyloxybenzoic herbicide, pyribenzoxim, a soil metabolism study was carried out with [14C]pyribenzoxim applied to a sandy loam soil under flooded conditions. The material balance of applied radioactivity ranged from 96.4 to 104.4% and from 96.1 to 101.9% for nonsterile and sterile soils, respectively. The half-life of [14C]pyribenzoxim was calculated to be approximately 1.3 and 9.4 days for nonsterile and sterile soils, respectively. The metabolites identified during the study were 2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M1) and 2-hydroxy-6-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M2), resulting from the cleavage of the ester bond and subsequent hydrolysis. The nonextractable radioactivity levels increased to 37.8% for nonsterile conditions at 50 days after treatment and to 38.2% for sterile conditions at 60 days after treatment. Fractionation of the nonextractable soil residues indicated that bound radioactivity was associated mainly with humin fraction. No significant volatile products or [14C]carbon dioxide was observed during the study. On the basis of these results, pyribenzoxim is considered to undergo rapid degradation in soil by microbial and chemical reactions, mainly hydrolysis, which limits its transfer to and accumulation in lower soil layers and groundwater. Therefore, the possibility of environmental contamination from the use of pyribenzoxim is expected to be very low.

  19. Proliferation of diversified clostridial species during biological soil disinfestation incorporated with plant biomass under various conditions.

    PubMed

    Mowlick, Subrata; Takehara, Toshiaki; Kaku, Nobuo; Ueki, Katsuji; Ueki, Atsuko

    2013-09-01

    Biological soil disinfestation (BSD) involves the anaerobic decomposition of plant biomass by microbial communities leading to control of plant pathogens. We analyzed bacterial communities in soil of a model experiment of BSD, as affected by biomass incorporation under various conditions, to find out the major anaerobic bacterial groups which emerged after BSD treatments. The soil was treated with Brassica juncea plants, wheat bran, or Avena strigosa plants, irrigated at 20 or 30 % moisture content and incubated at 25-30 °C for 17 days. The population of Fusarium oxysporum f. sp. spinaciae incorporated at the start of the experiment declined markedly for some BSD conditions and rather high concentrations of acetate and butyrate were detected from these BSD-treated soils. The polymerase chain reaction-denaturing gradient gel electrophoresis analysis based on the V3 region of 16S rRNA gene sequences from the soil DNA revealed that bacterial profiles greatly changed according to the treatment conditions. Based on the clone library analysis, phylogenetically diverse clostridial species appeared exceedingly dominant in the bacterial community of BSD soil incorporated with Brassica plants or wheat bran, in which the pathogen was suppressed completely. Species in the class Clostridia such as Clostridium saccharobutylicum, Clostridium acetobutylicum, Clostridium xylanovorans, Oxobacter pfennigii, Clostridium pasteurianum, Clostridium sufflavum, Clostridium cylindrosporum, etc. were commonly recognized as closely related species of the dominant clone groups from these soil samples.

  20. Delayed formation of zero-valent selenium nanoparticles by Bacillus mycoides SeITE01 as a consequence of selenite reduction under aerobic conditions

    PubMed Central

    2014-01-01

    Background Selenite (SeO32−) oxyanion shows severe toxicity to biota. Different bacterial strains exist that are capable of reducing SeO32− to non-toxic elemental selenium (Se0), with the formation of Se nanoparticles (SeNPs). These SeNPs might be exploited for technological applications due to their physico-chemical and biological characteristics. The present paper discusses the reduction of selenite to SeNPs by a strain of Bacillus sp., SeITE01, isolated from the rhizosphere of the Se-hyperaccumulator legume Astragalus bisulcatus. Results Use of 16S rRNA and GyrB gene sequence analysis positioned SeITE01 phylogenetically close to B. mycoides. On agarized medium, this strain showed rhizoid growth whilst, in liquid cultures, it was capable of reducing 0.5 and 2.0 mM SeO32− within 12 and 24 hours, respectively. The resultant Se0 aggregated to form nanoparticles and the amount of Se0 measured was equivalent to the amount of selenium originally added as selenite to the growth medium. A delay of more than 24 hours was observed between the depletion of SeO32 and the detection of SeNPs. Nearly spherical-shaped SeNPs were mostly found in the extracellular environment whilst rarely in the cytoplasmic compartment. Size of SeNPs ranged from 50 to 400 nm in diameter, with dimensions greatly influenced by the incubation times. Different SeITE01 protein fractions were assayed for SeO32− reductase capability, revealing that enzymatic activity was mainly associated with the membrane fraction. Reduction of SeO32− was also detected in the supernatant of bacterial cultures upon NADH addition. Conclusions The selenite reducing bacterial strain SeITE01 was attributed to the species Bacillus mycoides on the basis of phenotypic and molecular traits. Under aerobic conditions, the formation of SeNPs were observed both extracellularly or intracellullarly. Possible mechanisms of Se0 precipitation and SeNPs assembly are suggested. SeO32− is proposed to be enzimatically reduced to

  1. Bacterial diversity of soil aggregates of different sizes in various land use conditions

    NASA Astrophysics Data System (ADS)

    Ivanova, Ekaterina; Azida, Thakahova; Olga, Kutovaya

    2014-05-01

    The patterns of soil microbiome structure may be a universal and very sensitive indicator of soil quality (soil "health") used for optimization and biologization of agricultural systems. The understanding of how microbial diversity influenses, and is influenced by, the environment can only be attained by analyses at scales relevant to those at which processes influencing microbial diversity actually operate. The basic structural and functional unit of the soil is a soil aggregate, which is actually a microcosm of the associative co-existing groups of microorganisms that form characteristic ecological food chains. It is known that many important microbial processes occur in spatially segregated microenvironments in soil leading to a microscale biogeography. The Metagenomic library of typical chernozem in conditions of different land use systems was created. Total genomic DNA was extracted from 0.5 g of the frozen soil after mechanical destruction. Sample preparation and sequencing was performed on a GS Junior ("Roche»", Switzerland) according to manufacturer's recommendations, using the universal primers to the variable regions V4 gene 16S - rRNA - F515 (GTGCCAGCMGCCGCGGTAA) and R806 (GGACT-ACVSGGGTATCTAAT). It is shown that the system of land use is a stronger determinant of the taxonomic composition of the soil microbial community, rather than the size of the structural units. In soil samples from different land use systems the presence of accessory components was revealed. They may be used as indicators of processes of soil recovery, soil degradation or soil exhaustion processes occuring in the agroecosystems. The comparative analysis of microbial communities of chernozem aggregates investigated demonstrates the statistically valuable differences in the amount of bacterial phyla and Archean domain content as well as the species richness in aggregates of various size fractions. The occurrence of specific components in the taxonomic structure of micro-and macro

  2. Molybdenum isotope fractionation in soils: Influence of redox conditions, organic matter, and atmospheric inputs

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Pett-Ridge, J. C.; Opfergelt, S.; Guicharnaud, R. A.; Halliday, A. N.; Burton, K. W.

    2015-08-01

    Molybdenum isotope fractionation accompanying soil development is studied across three pedogenic gradients encompassing a range of controlling factors. These factors include variable redox conditions, organic matter content, Fe and Mn oxy(hydr)oxide content, mineral composition, degree of weathering, pH, type and amount of atmospheric inputs, age, climate, and underlying rock type. Soil profiles from the island of Maui (Hawaii) along a precipitation gradient ranging from 850 to 5050 mm mean annual precipitation show a decrease in average soil δ98Mo from -0.04 ± 0.11‰ at the driest, most oxic site, which is indistinguishable from the basalt parent material (-0.09 ± 0.08‰), to -0.33 ± 0.10‰ at the wettest, most reducing site. A suite of 6 Icelandic soils display a broad trend with heavier δ98Mo values (up to +1.50 ± 0.09‰) in soil horizons that are more weathered and have higher organic matter content. Selective extractions of Mo from different soil components indicate that the association with organic matter and silicate or Ti-oxide residue dominates retention of Mo in these soils, with adsorption on Fe and Mn oxy(hydr)oxides playing a lesser role. Across all basaltic soils, δ98Mo values are lighter in soils that exhibit the most net Mo loss relative to the parent material, and δ98Mo values are heavier in soils that exhibit net Mo gains. A well-drained regolith profile in the Luquillo Mountains of Puerto Rico developed on quartz diorite shows heavier δ98Mo values than the parent material (up to +0.71 ± 0.10‰ with an integrated profile average of +0.28 ± 0.10‰) in soil and shallower saprolite, despite overall moderate loss of 28% of Mo relative to the bedrock. However, the deeper saprolite is unfractionated from bedrock (-0.01 ± 0.10‰, quartz diorite bedrock) indicating that rock weathering dissolution processes and secondary clay formation do not fractionate Mo isotopes. Our data suggest that the Mo mass balance and isotope composition of

  3. Influence of green waste compost on azimsulfuron dissipation and soil functions under oxic and anoxic conditions.

    PubMed

    García-Jaramillo, M; Cox, L; Hermosín, M C; Cerli, C; Kalbitz, K

    2016-04-15

    Concerns have been raised over the sustainability of intensive rice cultivation, where the use of chemical fertilizers and pesticides has been associated with numerous environmental problems. The objective of this study was to test the effect of the herbicide azimsulfuron on important soil functions as affected by amendment with a byproduct of the olive oil industry. Soil was collected from a Mediterranean rice field. Part of it was amended with alperujo compost (AC). Amended and unamended soils were incubated for 43days in presence or not of azimsulfuron, under anoxic-flooded (AF) and oxic-unflooded (OU) conditions. We monitored the dissipation of the herbicide azimsulfuron, C mineralization, soil microbial biomass (SMB) and dissolved organic carbon (DOC) content and its nature. Under AF conditions, the application of compost produced an increase in the dissipation of the herbicide (up to 12.4%). It was related with the higher DOC content, 4 times higher than under OU conditions. Though increases in carbon turnover (under AF and OU conditions) and reduction of SMBC after herbicide application (only under AF conditions) were observed, the differences were not statistically significant. The application of this organic amendment is presented as an efficient management strategy to increase C turnover in agricultural soils and reduce some of the negative effects derived from the application of azimsulfuron under flooded conditions.

  4. Influence of green waste compost on azimsulfuron dissipation and soil functions under oxic and anoxic conditions.

    PubMed

    García-Jaramillo, M; Cox, L; Hermosín, M C; Cerli, C; Kalbitz, K

    2016-04-15

    Concerns have been raised over the sustainability of intensive rice cultivation, where the use of chemical fertilizers and pesticides has been associated with numerous environmental problems. The objective of this study was to test the effect of the herbicide azimsulfuron on important soil functions as affected by amendment with a byproduct of the olive oil industry. Soil was collected from a Mediterranean rice field. Part of it was amended with alperujo compost (AC). Amended and unamended soils were incubated for 43days in presence or not of azimsulfuron, under anoxic-flooded (AF) and oxic-unflooded (OU) conditions. We monitored the dissipation of the herbicide azimsulfuron, C mineralization, soil microbial biomass (SMB) and dissolved organic carbon (DOC) content and its nature. Under AF conditions, the application of compost produced an increase in the dissipation of the herbicide (up to 12.4%). It was related with the higher DOC content, 4 times higher than under OU conditions. Though increases in carbon turnover (under AF and OU conditions) and reduction of SMBC after herbicide application (only under AF conditions) were observed, the differences were not statistically significant. The application of this organic amendment is presented as an efficient management strategy to increase C turnover in agricultural soils and reduce some of the negative effects derived from the application of azimsulfuron under flooded conditions. PMID:26849340

  5. Modeling Soil Sodicity Problems under Dryland and Irrigated Conditions: Case Studies in Argentina and Colombia

    NASA Astrophysics Data System (ADS)

    Pla-Sentís, Ildefonso

    2014-05-01

    Salt-affected soils, both saline and sodic, my develop both under dryland and irrigated conditions, affecting negatively the physical and chemical soil properties, the crop production and the animal and human health.Among the development processes of salt-affected soils, the processes of sodification have been generally received less attention and is less understood than the development of saline soils. Although in both of them, hydrological processes are involved in their development, in the case of sodic soils we have to consider some additional chemical and physicochemical reactions, making more difficult their modeling and prediction. In this contribution we present two case studies: one related to the development of sodic soils in the lowlands of the Argentina Pampas, under dryland conditions and sub-humid temperate climate, with pastures for cattle production; the other deals with the development of sodic soils in the Colombia Cauca Valley, under irrigated conditions and tropical sub-humid climate, in lands used for sugarcane cropping dedicated to sugar and ethanol production. In both cases the development of sodicity in the surface soil is mainly related to the effects of the composition and level of groundwater, affected in the case of Argentina Pampas by the off-site changes in dryland use and management in the upper zones and by the drainage conditions in the lowlands, and in the case of the Cauca Valley, by the on-site irrigation and drainage management in lands with sugarcane. There is shown how the model SALSODIMAR, developed by the main author, based on the balance of water and soluble componentes of both the irrigation water and groundwater under different water and land management conditions, may be adapted for the diagnosis and prediction of both problems, and for the selection of alternatives for their management and amelioration.

  6. Sensing technologies to measure metabolic activities in soil and assess its health conditions

    NASA Astrophysics Data System (ADS)

    De Cesare, Fabrizio; Macagnano, Antonella

    2013-04-01

    Soil is a complex ecosystem comprised of several and mutually interacting components, both abiotic (organo-mineral associations) and biotic (microbial and pedofaunal populations and plants), where a single parameter depends on other factors and affects the same and other factors, so that a network of influences among organisms coexists with the reciprocal actions between organisms and their environment. Therefore, it is difficult to undoubtedly determine what is the cause and what the effect within relationships between factors and processes. Soil is commonly studied through the evaluation and measurement of single parameters (e.g. the content of soil organic matter (SOM), microbial biomass, enzyme activities, pH, etc.), events (e.g. soil erosion, compaction, etc.) and processes (e.g. soil respiration, carbon fluxes, nitrification/denitrification, etc.), often carried out in laboratory conditions in order to limit the number of factors acting within the ecosystem under study, but missing the information about the global soil environment that way. In the last decade, several scientists have proposed and suggested the need for a holistic approach to soil ecosystems in different contexts. Recently, we have applied a sensing system developed in the last decades and capable of analysing complex mixtures of gases and volatiles (odours or aromas) in atmospheres, namely called electronic nose (EN). Typically, ENs are devices consisting of an array of differentially and partially specific, despite selective, sensors upon diverse coatings of sensitive films, i.e. interacting with single analytes of the same chemical class, despite not highly specific for a single substance, only, but showing also lower extent of cross-selectivity towards compounds of other chemical classes. ENs can be used in the classifications of odours by processing the collected responses of all sensors in the array through pattern recognition analyses, in order to obtain a chemical fingerprint

  7. Rates of Root and Organism Growth, Soil Conditions, and Temporal and Spatial Development of the Rhizosphere

    PubMed Central

    WATT, MICHELLE; SILK, WENDY K.; PASSIOURA, JOHN B.

    2006-01-01

    • Background Roots growing in soil encounter physical, chemical and biological environments that influence their rhizospheres and affect plant growth. Exudates from roots can stimulate or inhibit soil organisms that may release nutrients, infect the root, or modify plant growth via signals. These rhizosphere processes are poorly understood in field conditions. • Scope and Aims We characterize roots and their rhizospheres and rates of growth in units of distance and time so that interactions with soil organisms can be better understood in field conditions. We review: (1) distances between components of the soil, including dead roots remnant from previous plants, and the distances between new roots, their rhizospheres and soil components; (2) characteristic times (distance2/diffusivity) for solutes to travel distances between roots and responsive soil organisms; (3) rates of movement and growth of soil organisms; (4) rates of extension of roots, and how these relate to the rates of anatomical and biochemical ageing of root tissues and the development of the rhizosphere within the soil profile; and (5) numbers of micro-organisms in the rhizosphere and the dependence on the site of attachment to the growing tip. We consider temporal and spatial variation within the rhizosphere to understand the distribution of bacteria and fungi on roots in hard, unploughed soil, and the activities of organisms in the overlapping rhizospheres of living and dead roots clustered in gaps in most field soils. • Conclusions Rhizosphere distances, characteristic times for solute diffusion, and rates of root and organism growth must be considered to understand rhizosphere development. Many values used in our analysis were estimates. The paucity of reliable data underlines the rudimentary state of our knowledge of root–organism interactions in the field. PMID:16551700

  8. Contributions of groundwater conditions to soil and water salinization

    NASA Astrophysics Data System (ADS)

    Salama, Ramsis B.; Otto, Claus J.; Fitzpatrick, Robert W.

    Salinization is the process whereby the concentration of dissolved salts in water and soil is increased due to natural or human-induced processes. Water is lost through one or any combination of four main mechanisms: evaporation, evapotranspiration, hydrolysis, and leakage between aquifers. Salinity increases from catchment divides to the valley floors and in the direction of groundwater flow. Salinization is explained by two main chemical models developed by the authors: weathering and deposition. These models are in agreement with the weathering and depositional geological processes that have formed soils and overburden in the catchments. Five soil-change processes in arid and semi-arid climates are associated with waterlogging and water. In all represented cases, groundwater is the main geological agent for transmitting, accumulating, and discharging salt. At a small catchment scale in South and Western Australia, water is lost through evapotranspiration and hydrolysis. Saline groundwater flows along the beds of the streams and is accumulated in paleochannels, which act as a salt repository, and finally discharges in lakes, where most of the saline groundwater is concentrated. In the hummocky terrains of the Northern Great Plains Region, Canada and USA, the localized recharge and discharge scenarios cause salinization to occur mainly in depressions, in conjunction with the formation of saline soils and seepages. On a regional scale within closed basins, this process can create playas or saline lakes. In the continental aquifers of the rift basins of Sudan, salinity increases along the groundwater flow path and forms a saline zone at the distal end. The saline zone in each rift forms a closed ridge, which coincides with the closed trough of the groundwater-level map. The saline body or bodies were formed by evaporation coupled with alkaline-earth carbonate precipitation and dissolution of capillary salts. Résumé La salinisation est le processus par lequel la

  9. No-tillage lessens soil CO2 emissions the most under arid and sandy soil conditions: results from a meta-analysis

    NASA Astrophysics Data System (ADS)

    Abdalla, Khatab; Chivenge, Pauline; Ciais, Philippe; Chaplot, Vincent

    2016-06-01

    The management of agroecosystems plays a crucial role in the global carbon cycle with soil tillage leading to known organic carbon redistributions within soils and changes in soil CO2 emissions. Yet, discrepancies exist on the impact of tillage on soil CO2 emissions and on the main soil and environmental controls. A meta-analysis was conducted using 46 peer-reviewed publications totaling 174 paired observations comparing CO2 emissions over entire seasons or years from tilled and untilled soils across different climates, crop types and soil conditions with the objective of quantifying tillage impact on CO2 emissions and assessing the main controls. On average, tilled soils emitted 21 % more CO2 than untilled soils, which corresponded to a significant difference at P<0.05. The difference increased to 29 % in sandy soils from arid climates with low soil organic carbon content (SOCC < 1 %) and low soil moisture, but tillage had no impact on CO2 fluxes in clayey soils with high background SOCC (> 3 %). Finally, nitrogen fertilization and crop residue management had little effect on the CO2 responses of soils to no-tillage. These results suggest no-tillage is an effective mitigation measure of carbon dioxide losses from dry land soils. They emphasize the importance of including information on soil factors such as texture, aggregate stability and organic carbon content in global models of the carbon cycle.

  10. Bacterial diversity and spoilage-related microbiota associated with freshly prepared chicken products under aerobic conditions at 4°C.

    PubMed

    Liang, Rongrong; Yu, Xiaoqiao; Wang, Renhuan; Luo, Xin; Mao, Yanwei; Zhu, Lixian; Zhang, Yimin

    2012-06-01

    This study analyzed the bacterial diversity and spoilage-related microbiota associated with freshly prepared chicken products stored aerobically at 4°C, using "bone and chicken string," a product popular in the People's Republic of China, as the study subject. Samples collected from three different factories were tray packaged with cling film and stored at 4°C. Bacterial diversity and dominant bacteria were analyzed using PCR amplification and denaturing gradient gel electrophoresis. Combined with selective cultivation of the dominant bacteria and correlation analysis, the dominant spoilage microbiota was determined. The results showed that bacterial diversity varied with different manufacturers. Such bacteria as Acinetobacter sp., Carnobacterium sp., Rahnella sp., Pseudomonas sp., Brochothrix sp., and Weissella sp. were detected in freshly prepared chicken products during storage. And Carnobacterium sp., Pseudomonas sp., and Brochothrix sp. bacteria were the common dominant spoilage bacteria groups in most freshly prepared chicken products from different factories. Carnobacterium was, for the first time, shown to be an important contributor to the spoilage-related microflora of freshly prepared chicken products stored aerobically under refrigeration. Our work shows the bacterial diversity and dominant spoilage microbiota of freshly prepared chicken products stored aerobically under refrigeration.

  11. IT-based soil quality evaluation for agroecologically smart land-use planning in RF conditions

    NASA Astrophysics Data System (ADS)

    Vasenev, Ivan

    2016-04-01

    Activated in the first decades of XXI century global climate, economy and farming changes sharply actualized novel IT-based approaches in soil quality evaluation to address modern agricultural issues with agroecologically smart land-use planning. Despite global projected climate changes will affect a general decline of crop yields (IPCC 2014), RF boreal and subboreal regions will benefit from predicted and already particularly verified temperature warming and increased precipitation (Valentini, Vasenev, 2015) due to essential increasing of growing season length and mild climate conditions favorable for most prospective crops and best available agrotechnologies. However, the essential spatial heterogeneity is mutual feature for most natural and man-changed soils at the Central European region of Russia which is one of the biggest «food baskets» in RF. In these conditions potentially favorable climate circumstances will increase not only soil fertility and workability features but also their dynamics and spatial variability that determine crucial issues of IT-based soil quality evaluation systems development and agroecologically smart farming planning. Developed and verified within the LAMP project (RF Governmental projects #11.G34.31.0079 and #14.120.14.4266) regionally adapted DSS (ACORD-R - RF #2012612944) gives effective informational and methodological support for smart farming agroecological optimization in global climate and farming changes challenges. Information basis for agroecologically smart land-use planning consists of crops and agrotechnologies requirements, regional and local systems of agroecological zoning, local landscape and soil cover patterns, land quality and degradation risk assessments, current and previous farming practices results, agroclimatic predictions and production agroecological models, environmental limitations and planned profitability, fertilizing efficiency DSS ACORD-R. Smart land-use practice refers to sustainable balance

  12. Activity and stability of a complex bacterial soil community under simulated Martian conditions

    NASA Astrophysics Data System (ADS)

    Hansen, Aviaja Anna; Merrison, Jonathan; Nørnberg, Per; Aagaard Lomstein, Bente; Finster, Kai

    2005-04-01

    A simulation experiment with a complex bacterial soil community in a Mars simulation chamber was performed to determine the effect of Martian conditions on community activity, stability and survival. At three different depths in the soil core short-term effects of Martian conditions with and without ultraviolet (UV) exposure corresponding to 8 Martian Sol were compared. Community metabolic activities and functional diversity, measured as glucose respiration and versatility in substrate utilization, respectively, decreased after UV exposure, whereas they remained unaffected by Martian conditions without UV exposure. In contrast, the numbers of culturable bacteria and the genetic diversity were unaffected by the simulated Martian conditions both with and without UV exposure. The genetic diversity of the soil community and of the colonies grown on agar plates were evaluated by denaturant gradient gel electrophoresis (DGGE) on DNA extracts. Desiccation of the soil prior to experimentation affected the functional diversity by decreasing the versatility in substrate utilization. The natural dominance of endospores and Gram-positive bacteria in the investigated Mars-analogue soil may explain the limited effect of the Mars incubations on the survival and community structure. Our results suggest that UV radiation and desiccation are major selecting factors on bacterial functional diversity in terrestrial bacterial communities incubated under simulated Martian conditions. Furthermore, these results suggest that forward contamination of Mars is a matter of great concern in future space missions.

  13. [Optimizing remediation conditions of non-thermal plasma for DDTs heavily contaminated soil].

    PubMed

    Chen, Hai-Hong; Luo, Yong-Ming; Teng, Ying; Liu, Wu-Xing; Pan, Cheng; Li, Zhen-Gao; Huang, Yu-Juan

    2013-01-01

    A series of experiments were carried out in a non-thermal reactor to remove DDTs in heavily contaminated soil by dielectric barrier discharge (DBD). The study aims to investigate the effects of soil properties (including soil particle size and soil water content) and equipment working parameters (e. g. the plasma power, the processing time and discharge atmosphere) on the removal of DDTs from soil. The results showed that DDTs in soil were significantly degraded by the non-thermal plasma produced by dielectric barrier discharge. Removal rate of DDTs increased with increasing processing time. The removal efficiency of DDTs ranged from 95.3% to 99.9% in 20 minutes. The optimum conditions were as follows: 1 kW of the plasma power, 20 minutes of processing time in air discharge atmosphere, 0-0.9 mm soil particle size and 4.5% -10.5% of soil moisture content. The results also showed that o,p'-DDE might be the intermediate dechlorination and dehydrogenation product of the o,p'-DDT after the oxidization.

  14. Agricultural machineries wheeling and soil qualities mapping in climatic changes conditions

    NASA Astrophysics Data System (ADS)

    Bergonzoli, S.; Servadio, P.

    2012-04-01

    and on control areas, a software GIS was used. Results shown the highest level of soil compaction caused by the traffic of WTN in term of CI and SS. In fact, increment ratio respect to the control measured after the tractors pass were: CI = 0.65 and 0.14 for WTN and for WTEL respectively; SS = 0.65 and 0.46 for WTN and WTEL respectively. Comparing the two different tires, significant differences were found particularly in the surface layers (0-0.20 m depth): mean values of CI and SS were higher for WTN (0.47 and 1.60 respectively) respect to WTEL. Track area covered by the two treatments respect to the whole field (16.32 ha) were: 0.025 for treatment WTN (0.27 m tires width) having an operative work width of 24 m ; 0.075 for treatment WTEL (0.85 m tires width) having an operative work width of 14 m. Results of this study highlighted that, in these field conditions (clay soil, water content over field capacity), tractor pass with very narrow tires caused a soil compaction level too high up to be impossible to traffic into the field. To operate at these soil water content conditions a tractors fitted with low aspect ratio and low inflation pressure tires is necessary. With lower soil water content, narrow tires allow carrying out fertilization into the inter-row avoiding crop trampling and compacting less percentage of field area respect to the a tractor equipped with large tires. Key words: Tractor, Soil trafficability, Soil compaction, Tires, GPS, GIS. Acknowledgements This work was carried out under the auspices of the special project "Sceneries of adaptation of the Italian agriculture to the climatic changes" (AGROSCENARI) of the Agricultural Research Council, and Italian Ministry of the Agricultural and Forestry Politics.

  15. IT-based soil quality evaluation for agroecologically smart land-use planning in RF conditions

    NASA Astrophysics Data System (ADS)

    Vasenev, Ivan

    2016-04-01

    Activated in the first decades of XXI century global climate, economy and farming changes sharply actualized novel IT-based approaches in soil quality evaluation to address modern agricultural issues with agroecologically smart land-use planning. Despite global projected climate changes will affect a general decline of crop yields (IPCC 2014), RF boreal and subboreal regions will benefit from predicted and already particularly verified temperature warming and increased precipitation (Valentini, Vasenev, 2015) due to essential increasing of growing season length and mild climate conditions favorable for most prospective crops and best available agrotechnologies. However, the essential spatial heterogeneity is mutual feature for most natural and man-changed soils at the Central European region of Russia which is one of the biggest «food baskets» in RF. In these conditions potentially favorable climate circumstances will increase not only soil fertility and workability features but also their dynamics and spatial variability that determine crucial issues of IT-based soil quality evaluation systems development and agroecologically smart farming planning. Developed and verified within the LAMP project (RF Governmental projects #11.G34.31.0079 and #14.120.14.4266) regionally adapted DSS (ACORD-R - RF #2012612944) gives effective informational and methodological support for smart farming agroecological optimization in global climate and farming changes challenges. Information basis for agroecologically smart land-use planning consists of crops and agrotechnologies requirements, regional and local systems of agroecological zoning, local landscape and soil cover patterns, land quality and degradation risk assessments, current and previous farming practices results, agroclimatic predictions and production agroecological models, environmental limitations and planned profitability, fertilizing efficiency DSS ACORD-R. Smart land-use practice refers to sustainable balance

  16. How do soil physical conditions for crop growth vary over time under established contrasting tillage regimes?

    NASA Astrophysics Data System (ADS)

    Hallett, Paul; Stobart, Ron; Valentine, Tracy; George, Timothy; Morris, Nathan; Newton, Adrian; McKenzie, Blair

    2014-05-01

    When plant breeders develop modern cereal varieties for the sustainable intensification of agriculture, insufficient thought is given to the impact of tillage on soil physical conditions for crop production. In earlier work, we demonstrated that barley varieties that perform best in ploughed soil (the approach traditionally used for breeding trials) were not the same as those performing best under shallow non-inversion or zero-tillage. We also found that the Quantitative Trait Loci (QTL) associated with improved phosphorus uptake, and hence useful for marker assisted breeding, were not robust between different tillage regimes. The impact of the soil environment had greater impact than the genetics in GxE interactions. It is obvious that soil tillage should be considered when breeding the next generation of crops. Tillage may also have important impacts on carbon storage, but we found that despite greater soil carbon at shallow depths under non-inversion tillage, the carbon stored throughout the soil profile was not affected by tillage. Studies on soil tillage impacts to crop productivity and soil quality are often performed in one season, on single sites that have had insufficient time to develop. Our current research explores multiple sites, on different soils, with temporal measurements of soil physical conditions under contrasting tillage regimes. We use the oldest established contemporary tillage experiments in the United Kingdom, with all sites sharing ploughed and shallow (7cm) non-inversion tillage treatments. In eastern Scotland (Mid Pilmore), the site also has zero tillage and deep ploughing (40 cm) treatments, and was established 11 years ago. In east England there are two sites, both also having a deep non-inversion tillage treatment, and they were established 6 (New Farm Systems) and 8 (STAR) years ago. We measure a range of crop and soil properties at sowing, one month after sowing and post-harvest, including rapid lab based assays that allow high

  17. Optimal Thermolysis Conditions for Soil Carbon Storage on Plant Residue Burning: Modeling the Trade-Off between Thermal Decomposition and Subsequent Biodegradation.

    PubMed

    Kajiura, Masako; Wagai, Rota; Hayashi, Kentaro

    2015-01-01

    Field burning of plant biomass is a widespread practice that provides charred materials to soils. Its impact on soil C sequestration remains unclear due to the heterogeneity of burning products and difficulty in monitoring the material's biodegradation in fields. Basic information is needed on the relationship between burning conditions and the resulting quantity/quality of residue-derived C altered by thermal decomposition and biodegradation. In this study, we thermolyzed residues (rice straw and husk) at different temperatures (200-600°C) under two oxygen availability conditions and measured thermal mass loss, C compositional change by solid-state C NMR spectroscopy, and biodegradability of the thermally altered residues by laboratory aerobic incubation. A trade-off existed between thermal and microbial decomposition: when burned at higher temperatures, residues experience a greater mass loss but become more recalcitrant via carbonization. When an empirical model accounting for the observed trade-off was projected over 10 to 10 yr, we identified the threshold temperature range (330-400°C) above and below which remaining residue C is strongly reduced. This temperature range corresponded to the major loss of O-alkyl C and increase in aromatic C. The O/C molar ratios of the resultant residues decreased to 0.2 to 0.4, comparable to those of chars in fire-prone field soils reported previously. Although the negative impacts of biomass burning need to be accounted for, the observed relationship may help to assess the long-term fate of burning-derived C and to enhance soil C sequestration. PMID:25602338

  18. Effects of climatic conditions and soil properties on Cabernet Sauvignon berry growth and anthocyanin profiles.

    PubMed

    Cheng, Guo; He, Yan-Nan; Yue, Tai-Xin; Wang, Jun; Zhang, Zhen-Wen

    2014-01-01

    Climatic conditions and soil type have significant influence on grape ripening and wine quality. The reported study was conducted in two "Cabernet Sauvignon (Vitis vinifera L.V)" vineyards located in Xinjiang, a semiarid wine-producing region of China during two vintages (2011 and 2012). The results indicate that soil and climate affected berry growth and anthocyanin profiles. These two localities were within a distance of 5 km from each other and had soils of different physical and chemical composition. For each vineyard, the differences of anthocyanin concentrations, and parameters concerning berry growth and composition between the two years could be explained by different climatic conditions. Soil effect was studied by investigation of differences in berry composition and anthocyanin profiles between the two vineyards in the same year, which could be explained mainly by the different soil properties, vine water and nitrogen status. Specifically, the soils with less water and organic matter produced looser clusters, heavier berry skins and higher TSS, which contributed to the excellent performance of grapes. Compared with 2011, the increases in anthocyanin concentrations for each vineyard in 2012 could be attributed to smaller number of extreme temperature (>35 °C) days and rainfall, lower vine water status and N level. The explanation for higher anthocyanin concentrations in grape skins from the soils with less water and organic matter could be the vine status differences, lighter berry weight and heavier skin weight at harvest. In particular, grapes from the soils with less water and organic matter had higher levels of 3'5'-substituded, O-methylated and acylated anthocyanins, which represented a positive characteristic conferring more stable pigmentation to the corresponding wine in the future. The present work clarifies the effects of climate and soil on berry growth and anthocyanin profiles, thus providing guidance for production of high-quality wine grapes

  19. Effects of climatic conditions and soil properties on Cabernet Sauvignon berry growth and anthocyanin profiles.

    PubMed

    Cheng, Guo; He, Yan-Nan; Yue, Tai-Xin; Wang, Jun; Zhang, Zhen-Wen

    2014-09-02

    Climatic conditions and soil type have significant influence on grape ripening and wine quality. The reported study was conducted in two "Cabernet Sauvignon (Vitis vinifera L.V)" vineyards located in Xinjiang, a semiarid wine-producing region of China during two vintages (2011 and 2012). The results indicate that soil and climate affected berry growth and anthocyanin profiles. These two localities were within a distance of 5 km from each other and had soils of different physical and chemical composition. For each vineyard, the differences of anthocyanin concentrations, and parameters concerning berry growth and composition between the two years could be explained by different climatic conditions. Soil effect was studied by investigation of differences in berry composition and anthocyanin profiles between the two vineyards in the same year, which could be explained mainly by the different soil properties, vine water and nitrogen status. Specifically, the soils with less water and organic matter produced looser clusters, heavier berry skins and higher TSS, which contributed to the excellent performance of grapes. Compared with 2011, the increases in anthocyanin concentrations for each vineyard in 2012 could be attributed to smaller number of extreme temperature (>35 °C) days and rainfall, lower vine water status and N level. The explanation for higher anthocyanin concentrations in grape skins from the soils with less water and organic matter could be the vine status differences, lighter berry weight and heavier skin weight at harvest. In particular, grapes from the soils with less water and organic matter had higher levels of 3'5'-substituded, O-methylated and acylated anthocyanins, which represented a positive characteristic conferring more stable pigmentation to the corresponding wine in the future. The present work clarifies the effects of climate and soil on berry growth and anthocyanin profiles, thus providing guidance for production of high-quality wine grapes

  20. [Leaching Remediation of Copper and Lead Contaminated Lou Soil by Saponin Under Different Conditions].

    PubMed

    Deng, Hong-xia; Yang, Ya-li; Li, Zhen; Xu, Yan; Li, Rong-hua; Meng, Zhao-fu; Yang, Ya-ti

    2015-04-01

    In order to investigate the leaching remediation effect of the eco-friendly biosurfactant saponin for Cu and Pb in contaminated Lou soil, batch tests method was used to study the leaching effect of saponin solution on single Cu, Pb contaminated Lou soil and mixed Cu and Pb contaminated Lou soil under different conditions such as reaction time, mass concentration of saponin, pH, concentration of background electrolyte and leaching times. The results showed that the maximum leaching removal effect of Cu and Pb in contaminated Lou soil was achieved by complexation of the heavy metals with saponin micelle, when the mass concentration of saponin solution was 50 g x L(-1), pH was 5.0, the reaction time was 240 min, and there was no background electrolyte. In single and mixed contaminated Lou soil, the leaching percentages of Cu were 29.02% and 25.09% after a single leaching with 50 g x L(-1) saponin under optimal condition, while the single leaching percentages of Pb were 31.56% and 28.03%, respectively. The result indicated the removal efficiency of Pb was more significant than that of Cu. After 4 times of leaching, the cumulative leaching percentages of Cu reached 58.92% and 53.11%, while the cumulative leaching percentages of Pb reached 77.69% and 65.32% for single and mixed contaminated Lou soil, respectively. The fractionation results of heavy metals in soil before and after a single leaching showed that the contents of adsorbed and exchangeable Cu and Pb increased in the contaminated soil, while the carbonate-bound, organic bound and sulfide residual Cu and Pb in the contaminated Lou soil could be effectively removed by saponin.

  1. Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays

    NASA Astrophysics Data System (ADS)

    Bittelli, Marco; Valentino, Roberto; Salvatorelli, Fiorenzo; Rossi Pisa, Paola

    2012-11-01

    Shallow landslides frequently occur during transient rainfall infiltration and under partially saturated conditions. However, a detailed analysis of what triggers them, particularly in clayey soils, is often hindered by the lack of field measurements. It is uncommon, in fact, to capture their occurrence in an instrumented natural slope. This paper presents results from an integrated field experiment monitoring the soil-water and displacement conditions that lead to the occurrence of a shallow landslide in partially saturated clays. The integration of a variety of experimental techniques allowed for the examination of interplay between soil hydrological and mechanical properties. This research also evaluates a slope stability model based on the suction stress concept. Since the model was applied after the occurrence of the landslide, the results are interpreted as a hind-casting technique for model evaluation. Nevertheless, the detailed field measurements acquired during the monitoring activity and the occurrence of a landslide during the experiment provided significant information on model parameters and data interpretation. The station provides remote satellite monitoring of data on weather variables, soil water content and soil suction. A time domain reflectometry cable was installed vertically to detect potential soil failure. The experimental area had a high probability of landslide occurrence. Indeed, slope failure occurred during the observation period, showing the effectiveness of the station in detecting the occurrence, time and depth of landslides. The landslide was triggered in consequence of changes in suction stress. The failure plane occurred at a depth of 1.4 m, corresponding to the interface between a superficial layer of higher permeability of 1 to 1.45 m thickness, slipping over a compacted substrate having lower permeability. The analysis allowed for testing of the validity of the model and the description of the triggering mechanisms of the

  2. Volatilization modeling of two herbicides from soil in a wind tunnel experiment under varying humidity conditions.

    PubMed

    Schneider, Martina; Goss, Kai-Uwe

    2012-11-20

    Volatilization of pesticides from the bare soil surface is drastically reduced when the soil is under dry conditions (i.e., water content lower than the permanent wilting point). This effect is caused by the hydrated mineral surfaces that become available as additional sorption sites under dry conditions. However, established volatilization models do not explicitly consider the hydrated mineral surfaces as an independent sorption compartment and cannot correctly cover the moisture effect on volatilization. Here we integrated the existing mechanistic understanding of sorption of organic compounds to mineral surfaces and its dependence on the hydration status into a simple volatilization model. The resulting model was tested with reported experimental data for two herbicides from a wind tunnel experiment under various well-defined humidity conditions. The required equilibrium sorption coefficients of triallate and trifluralin to the mineral surfaces, K(min/air), at 60% relative humidity were fitted to experimental data and extrapolated to other humidity conditions. The model captures the general trend of the volatilization in different humidity scenarios. The results reveal that it is essential to have high quality input data for K(min/air), the available specific surface area (SSA), the penetration depth of the applied pesticide solution, and the humidity conditions in the soil. The model approach presented here in combination with an improved description of the humidity conditions under dry conditions can be integrated into existing volatilization models that already work well for humid conditions but still lack the mechanistically based description of the volatilization process under dry conditions.

  3. Selenium and sulfur relationships in alfalfa and soil under field conditions, San Joaquin Valley, California

    USGS Publications Warehouse

    Severson, R.C.; Gough, L.P.

    1992-01-01

    Relationships between total Se and S or soluble SeO4 and SO4 in soils and tissue concentrations in alfalfa (Medicago sativa L.), under field conditions in the San Joaquin Valley of California, suggest that the rate of accumulation of Se in alfalfa may be reduced in areas where high Se and S concentrations in soils were measured. These data suggest that the balance between carbonate and sulfate minerals in soil may have a greater influence on uptake of Se by alfalfa than does the balance of SeO4 and SO4 in soil solution. Soil and alfalfa were sampled from areas representing a wide range in soil Se and S concentrations. Specific sampling locations were selected based on a previous study of Se, S, and other elements where 721 soil samples were collected to map landscape variability and distribution of elements. Six multiple-linear regression equations were developed between total and/or soluble soil chemical constituents and tissue concentrations of Se in alfalfa. We chose a regression model that accounted for 72% of the variability in alfalfa Se concentrations based on an association of elements in soil (total C, S, Se, and Sr) determined by factor analysis. To prepare a map showing the spatial distribution of estimated alfalfa Se concentrations, the model was applied to the data from the previously collected 721 soil samples. Estimated alfalfa Se concentrations in most of the study area were within a range that is predicted to produce alfalfa with neither Se deficiency nor toxicity when consumed by livestock. A few small areas are predicted to produce alfalfa that potentially would not meet minimum dietary needs of livestock.

  4. Evaporation from soils subjected to natural boundary conditions at the land-atmospheric interface

    NASA Astrophysics Data System (ADS)

    Smits, K.; Illngasekare, T.; Ngo, V.; Cihan, A.

    2012-04-01

    Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance in semiarid and arid regions. However, there is no agreement on the best methodology to determine evaporation under different boundary conditions at the land surface. This becomes critical in developing models that couples land to the atmosphere. Because it is difficult to measure evaporation from soil, with the exception of using lysimeters, numerous formulations have been proposed to establish a relationship between the rate of evaporation and soil moisture and/or soil temperature and thermal properties. Different formulations vary in how they partition available energy. A need exists to systematically compare existing methods to experimental data under highly controlled conditions not achievable in the field. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmospheric interface to test different conceptual and mathematical formulations for the soil surface boundary conditions to develop appropriate numerical models to be used in simulations. In this study, to better understand the coupled water-vapor-heat flow processes in the shallow subsurface near the land surface, we modified a previously developed theory by Smits et al. [2011] that allows non-equilibrium liquid/gas phase change with gas phase vapor diffusion to better account for dry soil conditions. The model did not implement fitting parameters such as a vapor enhancement factor that is commonly introduced into the vapor diffusion coefficient as an arbitrary multiplication factor. In order to experimentally test the numerical formulations/code, we performed a two-dimensional physical model experiment under varying boundary conditions using test sand for which the hydraulic and thermal properties were well characterized. Precision data under well-controlled transient heat and

  5. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes.

    PubMed

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar ('Cocodrie' and 'Rondo'), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice.

  6. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes

    PubMed Central

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E.; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar (‘Cocodrie’ and ‘Rondo’), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice. PMID:26978525

  7. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes.

    PubMed

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar ('Cocodrie' and 'Rondo'), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice. PMID:26978525

  8. Analytical solution describing pesticide volatilization from soil affected by a change in surface condition.

    PubMed

    Yates, S R

    2009-01-01

    An analytical solution describing the fate and transport of pesticides applied to soils has been developed. Two pesticide application methods can be simulated: point-source applications, such as idealized shank or a hot-gas injection method, and a more realistic shank-source application method that includes a vertical pesticide distribution in the soil domain due to a soil fracture caused by a shank. The solutions allow determination of the volatilization rate and other information that could be important for understanding fumigant movement and in the development of regulatory permitting conditions. The solutions can be used to characterize differences in emissions relative to changes in the soil degradation rate, surface barrier conditions, application depth, and soil packing. In some cases, simple algebraic expressions are provided that can be used to obtain the total emissions and total soil degradation. The solutions provide a consistent methodology for determining the total emissions and can be used with other information, such as field and laboratory experimental data, to support the development of fumigant regulations. The uses of the models are illustrated by several examples.

  9. Leaching of oryzalin and diuron through undisturbed vineyard soil columns under outdoor conditions.

    PubMed

    Landry, David; Dousset, Sylvie; Andreux, Francis

    2006-03-01

    Field studies monitoring herbicide pollution in the vineyards of Burgundy (France) have revealed that drinking water reservoirs are contaminated with several pre-emergence herbicides. An assessment of the leaching of two such herbicides, diuron and oryzalin, was therefore performed using lysimeters, under outdoor conditions, from May 2001 to May 2002. Four vineyard soils from Vosne-Romanée (Burgundy) were chosen along a topolithosequence: a rendosol and three calcosols. After 673 mm of rainfall, greater amounts of diuron than oryzalin were measured in percolates: respectively 0.10-0.84% and 0.02-0.43% of applied herbicide, depending on soils. Measurements for diuron metabolites detected greater amounts of DCPMU than DCPU in the percolates: respectively 0.05-0.13% and 0-0.04% of the applied diuron. At the end of the monitoring period, more residues of diuron than oryzalin were recovered in the soil profiles: respectively 4.6-9% and 1.4-4.4%. The oryzalin residues were found mainly in the upper 10 cm of soil columns, whereas diuron residues were present in the whole core. The mobility of both oryzalin and diuron seems fairly well-related to soil organic carbon content; the mobility of diuron is also related to soil texture (sand and coarse material contents). Under such experimental conditions, this study confirms that diuron leaching, and therefore potential groundwater contamination, is greater than that of oryzalin.

  10. Green synthesis of Pd/CuO nanoparticles by Theobroma cacao L. seeds extract and their catalytic performance for the reduction of 4-nitrophenol and phosphine-free Heck coupling reaction under aerobic conditions.

    PubMed

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Rostami-Vartooni, Akbar; Bagherzadeh, Mojtaba

    2015-06-15

    We report the green synthesis of palladium/CuO nanoparticles (Pd/CuO NPs) using Theobroma cacao L. seeds extract and their catalytic activity for the reduction of 4-nitrophenol and Heck coupling reaction under aerobic conditions. The catalyst was characterized using the powder XRD, TEM, EDS, UV-vis and FT-IR. This method has the advantages of high yields, elimination of surfactant, ligand and homogeneous catalysts, simple methodology and easy work up. The catalyst can be recovered from the reaction mixture and reused several times without any significant loss of catalytic activity.

  11. One-pot approach to 1,2-disubstituted indoles via Cu(II)-catalyzed coupling/cyclization under aerobic conditions and its application for the synthesis of polycyclic indoles.

    PubMed

    Gao, Jilong; Shao, Yingying; Zhu, Jiaoyan; Zhu, Jiaqi; Mao, Hui; Wang, Xiaoxia; Lv, Xin

    2014-10-01

    A straightforward assembly of 1,2-disubstituted indoles has been developed through a Cu(II)-catalyzed domino coupling/cyclization process. Under aerobic conditions, a wide range of 1,2-disubstituted indole derivatives were efficiently and facilely synthesized from 2-alkynylanilines and boronic acids. 2-(2-Bromoaryl)-1-aryl-1H-indoles, which were selectively generated in one pot under the Cu catalysis, afforded the indolo[1,2-f]phenanthridines via Pd-catalyzed intramolecular direct C(sp(2))-H arylation. The one-pot tandem approaches to the polycyclic indole derivatives were also successfully achieved. PMID:25211172

  12. Modeling soil evaporation efficiency in a range of soil and atmospheric conditions using a meta-analysis approach

    NASA Astrophysics Data System (ADS)

    Merlin, O.; Stefan, V. G.; Amazirh, A.; Chanzy, A.; Ceschia, E.; Er-Raki, S.; Gentine, P.; Tallec, T.; Ezzahar, J.; Bircher, S.; Beringer, J.; Khabba, S.

    2016-05-01

    A meta-analysis data-driven approach is developed to represent the soil evaporative efficiency (SEE) defined as the ratio of actual to potential soil evaporation. The new model is tested across a bare soil database composed of more than 30 sites around the world, a clay fraction range of 0.02-0.56, a sand fraction range of 0.05-0.92, and about 30,000 acquisition times. SEE is modeled using a soil resistance (rss) formulation based on surface soil moisture (θ) and two resistance parameters rss,ref and θefolding. The data-driven approach aims to express both parameters as a function of observable data including meteorological forcing, cut-off soil moisture value θ1/2 at which SEE=0.5, and first derivative of SEE at θ1/2, named Δθ1/2-1. An analytical relationship between >(rss,ref;θefolding) and >(θ1/2;Δθ1/2-1>) is first built by running a soil energy balance model for two extreme conditions with rss = 0 and rss˜∞ using meteorological forcing solely, and by approaching the middle point from the two (wet and dry) reference points. Two different methods are then investigated to estimate the pair >(θ1/2;Δθ1/2-1>) either from the time series of SEE and θ observations for a given site, or using the soil texture information for all sites. The first method is based on an algorithm specifically designed to accomodate for strongly nonlinear SEE>(θ>) relationships and potentially large random deviations of observed SEE from the mean observed SEE>(θ>). The second method parameterizes θ1/2 as a multi-linear regression of clay and sand percentages, and sets Δθ1/2-1 to a constant mean value for all sites. The new model significantly outperformed the evaporation modules of ISBA (Interaction Sol-Biosphère-Atmosphère), H-TESSEL (Hydrology-Tiled ECMWF Scheme for Surface Exchange over Land), and CLM (Community Land Model). It has potential for integration in various land-surface schemes, and real calibration capabilities using combined thermal and microwave

  13. Prediction of soil and ground water contamination with fungicides of different classes according to soil and climate conditions in Ukrain and other European countries.

    PubMed

    Vavrinevych, O; Antonenko, A; Omelchuk, S; Korshun, M; Bardov, V

    2015-05-01

    It was established that most of tested pesticides are moderately and low persistent in soil and climatic conditions of Ukraine, but more stable in Western and Northern Europe countries due to peculiarities of their climate type and soil characteristics. In addition, it was determined that all studied fungicides pertain to non- and low mobile compound (except moderately mobile pyrimethanil). Recommendations on application of studied fungicides in soil and climatic conditions of Ukraine and other European countries were given. PMID:26042452

  14. Prediction of soil and ground water contamination with fungicides of different classes according to soil and climate conditions in Ukrain and other European countries.

    PubMed

    Vavrinevych, O; Antonenko, A; Omelchuk, S; Korshun, M; Bardov, V

    2015-05-01

    It was established that most of tested pesticides are moderately and low persistent in soil and climatic conditions of Ukraine, but more stable in Western and Northern Europe countries due to peculiarities of their climate type and soil characteristics. In addition, it was determined that all studied fungicides pertain to non- and low mobile compound (except moderately mobile pyrimethanil). Recommendations on application of studied fungicides in soil and climatic conditions of Ukraine and other European countries were given.

  15. Microhabitat Effects on N2O Emissions from Floodplain Soils under Controlled Conditions

    NASA Astrophysics Data System (ADS)

    Ley, Martin; Lehmann, Moritz; Niklaus, Pascal; Frey, Beat; Kuhn, Thomas; Luster, Jörg

    2015-04-01

    Semi-terrestrial soils such as floodplain soils are considered to be potential hotspots of nitrous oxide (N2O) emissions. The quantitative assessment of N2O release from these hot spots under field conditions, and of the microbial pathways that underlie net N2O production (ammonium oxidation, nitrifier-denitrification, and denitrification) is challenging in the environment because of the high spatial and temporal variability. The production and consumption of N2O appears to be linked to the presence or absence of micro-niches, providing specific conditions that may be favorable to either of the microbial pathways that produce or consume N2O. The availability of oxygen, reactive organic carbon, and dissolved nitrogen substrates likely play key roles with regards to the net production of N2O. Previous field studies demonstrated, for example, that flooding can trigger "hot moments" of enhanced N2O emission through a close coupling of niches with high and low oxygen availabilities. Such microhabitat effects likely depend on soil aggregate formation, plant soil interactions in the rhizosphere and the degradation of organic matter accumulations. In order to assess how these factors can modulate N2O production and consumption under simulated flooding/drying conditions, we have set up a mesocosm experiment with model soils comprising various mixtures of N-rich floodplain soil aggregates (4000 - 250 µm representing large aggregates, or <250 µm representing small aggregates) and inert matrix material (glass beads of 150 - 250 µm size, or quartz sand of 2000 - 3200 µm size, respectively). Soils containing the different aggregate size groups were either planted with willow (Salix viminalis L.), mixed with leaf litter or left untreated. At several time points before, during and after a simulated flood event, we measure the net efflux rate of N2O. In addition, soil water content, redox potential as well as carbon and nitrogen substrate availability are monitored. In order to

  16. Soil texture and climatc conditions for biocrust growth limitation: a meta analysis

    NASA Astrophysics Data System (ADS)

    Fischer, Thomas; Subbotina, Mariia

    2015-04-01

    Along with afforestation, attempts have been made to combat desertification by managing soil crusts, and is has been reported that recovery rates of biocrusts are dependent on many factors, including the type, severity, and extent of disturbance; structure of the vascular plant community; conditions of adjoining substrates; availability of inoculation material; and climate during and after disturbance (Belnap & Eldridge 2001). Because biological soil crusts are known to be more stable on and to prefer fine substrates (Belnap 2001), the question arises as to how successful crust management practices can be applied to coarser soil. In previous studies we observed similar crust biomasses on finer soils under arid and on coarser soils under temperate conditions. We hypothesized that the higher water holding capacity of finer substrates would favor crust development, and that the amount of silt and clay in the substrate that is required for enhanced crust development would vary with changes in climatic conditions. In a global meta study, climatic and soil texture threshold values promoting BSC growth were derived. While examining literature sources, it became evident that the amount of studies to be incorporated into this meta analysis was reversely related to the amount of common environmental parameters they share. We selected annual mean precipitaion, mean temperature and the amount of silt and clay as driving variables for crust growth. Response variable was the "relative crust biomass", which was computed per literature source as the ratio between each individual crust biomass value of the given study to the study maximum value reported. We distinguished lichen, green algal, cyanobacterial and moss crusts. To quantify threshold conditions at which crust biomass responded to differences in texture and climate, we (I) determined correlations between bioclimatic variables, (II) calculated linear models to determine the effect of typical climatic variables with soil

  17. Colloid-Facilitated Transport of Cations in an Unsaturated Fractured Soil Under Transient Conditions

    SciTech Connect

    Ryan, Joseph

    2015-01-31

    Rainfall experiments were conducted using intact soil cores and an instrumented soil pedon to examine the effect of physical heterogeneity and rainfall characteristics on the mobilization of colloids, organic matter, cesium, and strontium in a fractured soil. To measure the spatial variability of infiltration of colloids and contaminants, samples were collected through a 19-port grid placed below the soil core in laboratory study and in 27 samplers at multiple depths in the soil pedon in the field study. Cesium and strontium were applied to the soil cores and the soil pedon prior to mobilization experiments. Rainwater solutions of multiple ionic strengths and organic matter concentrations were applied to the soil cores and soil pedon to mobilize in situ colloids, cesium, and strontium. The mobilization of colloids and metal cations occurred through preferential flow paths in the soil cores. Compared to steady rainfall, greater amounts of colloids were mobilized during rainfall interrupted by pauses, which indicates that the supply of colloids to be mobilized was replenished during the pauses. A maximum in the amount of mobilized colloids were mobilized during a rainfall following a pause of 2.5 d. Pauses of shorter or longer duration resulted in less colloid mobilization. Freeze-thaw cycles, a transient condition in winter, enhanced colloid mobilization and colloid-facilitated transport of cesium and strontium in the soil cores. The exchange of solutes between the soil matrix and macropores caused a hysteretic mobilization of colloids, cesium, and strontium during changes in ionic strength. Colloid-facilitated mobilization of cesium and strontium was important at low ionic strength in fractures where slow flow allowed greater exchange of flow between the fractures and the surrounding matrix. The release of cesium and strontium by cation exchange occurred at high ionic strength in fractures where there is a little exchange of pore water with the surrounding matrix

  18. A non-equilibrium model for soil heating and evaporation under extreme conditions

    NASA Astrophysics Data System (ADS)

    Massman, W. J.

    2014-12-01

    Extreme heating of soils during fires can have long-term and irreversible consequences and given the increasing use of prescribed fire by land managers and the increasing probability of wildfires associated with global warming, one approach to improving understanding of these consequences is to better understand and model the dynamics of the coupled heat, (liquid) moisture, and vapor transport in soils during extreme heating events. The present study describes a model developed to simulate non-equilibrium soil evaporation and the transport of heat, moisture, and water vapor under conditions during fires where the surface heating of the soil often ranges between 10,000 and 100,000 Wm-2 for several minutes to several hours. The Hertz-Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. Model performance is tested against laboratory measurements of soil temperature and moisture changes. Testing the present model with different formulations for soil hydraulic conductivity, water retention curve, water activity, and the non-equilibrium evaporative source term, indicates that virtually all the model's successes result from the use of a temperature dependent condensation coefficient in the evaporative source term, a rather surprising and unexpected result. On the other hand, the model solution is not a completely faithful representation of the laboratory data. Nevertheless, this new non-equilibrium model circumvents many of the problems that plagued an equilibrium model developed for the same purpose (Massman 2012: Water Resources Research 48, WR011710) and provides a much more physically realistic simulation than the earlier model. Finally, the present model should provide insight into modeling of heat and mass transport and evaporation, not only during high temperature and low moisture conditions, but for modeling these soil processes under less extreme environmental conditions as well.

  19. Land agroecological quality assessment in conditions of high spatial soil cover variability at the Pereslavskoye Opolye.

    NASA Astrophysics Data System (ADS)

    Morev, Dmitriy; Vasenev, Ivan

    2015-04-01

    The essential spatial variability is mutual feature for most natural and man-changed soils at the Central region of European territory of Russia. The original spatial heterogeneity of forest soils has been further complicated by a specific land-use history and human impacts. For demand-driven land-use planning and decision making the quantitative analysis and agroecological interpretation of representative soil cover spatial variability is an important and challenging task that receives increasing attention from private companies, governmental and environmental bodies. Pereslavskoye Opolye is traditionally actively used in agriculture due to dominated high-quality cultivated soddy-podzoluvisols which are relatively reached in organic matter (especially for conditions of the North part at the European territory of Russia). However, the soil cover patterns are often very complicated even within the field that significantly influences on crop yield variability and have to be considered in farming system development and land agroecological quality evaluation. The detailed investigations of soil regimes and mapping of the winter rye yield have been carried in conditions of two representative fields with slopes sharply contrasted both in aspects and degrees. Rye biological productivity and weed infestation have been measured in elementary plots of 0.25 m2 with the following analysis the quality of the yield. In the same plot soil temperature and moisture have been measured by portable devices. Soil sampling was provided from three upper layers by drilling. The results of ray yield detailed mapping shown high differences both in average values and within-field variability on different slopes. In case of low-gradient slope (field 1) there is variability of ray yield from 39.4 to 44.8 dt/ha. In case of expressed slope (field 2) the same species of winter rye grown with the same technology has essentially lower yield and within-field variability from 20 to 29.6 dt/ha. The

  20. Chromium Release from a COPR-Contaminated Soil at Varying Water Content and Redox Conditions.

    PubMed

    Matern, Katrin; Mansfeldt, Tim

    2016-07-01

    Many soils in the region of Kanpur, North India, are heavily affected by the leather industry and its upstream supplier sector, as indicated by elevated chromium (Cr) contents. Under reducing conditions-for instance, at water saturation after monsoon rain or flood irrigation-the dynamic and species distribution of Cr may be affected due to changes in redox potential (E). In this study, the influence of E on the speciation and release of Cr from a contaminated agricultural soil was investigated. A soil sample that was affected by hyperalkaline leachate from chromite ore processing residue, was taken and packed in soil columns, and subjected to a saturation-drainage-saturation cycle. After initial water saturation, the E dropped slowly to minimum values of around ‒100 mV (calculated to pH 7), while E was controlled by CrO/CrO(s), or CrO/(Fe,Cr)OOH redox couples. Soil drainage resulted in a quick return to oxidizing conditions; i.e., E > 300 mV. The Cr species distribution and release showed a clear trend with E. At the beginning of the experiment, under oxidizing and weakly reducing conditions (E range from >100 to 300 mV), Cr(VI) was released in particular. However, under moderately reducing conditions (E range from 100 to -100 mV), Cr was gradually immobilized and irreversible sequestered via reductive precipitation. The results presented in this study provide an improved understanding of the mobility of Cr(VI) in contaminated soils at varying water contents, which is essential for the evaluation of environmental risks in this region. PMID:27380074

  1. Biological space experiments for the simulation of Martian conditions: UV radiation and Martian soil analogues

    NASA Astrophysics Data System (ADS)

    Rettberg, P.; Rabbow, E.; Panitz, C.; Horneck, G.

    2004-01-01

    The survivability of resistant terrestrial microbes, bacterial spores of Bacillus subtilis, was investigated in the BIOPAN facility of the European Space Agency onboard of Russian Earth-orbiting FOTON satellites (BIOPAN I -III missions). The spores were exposed to different subsets of the extreme environmental parameters in space (vacuum, extraterrestrial solar UV, shielding by protecting materials like artificial meteorites). The results of the three space experiments confirmed the deleterious effects of extraterrestrial solar UV radiation which, in contrast to the UV radiation reaching the surface of the Earth, also contains the very energy-rich, short wavelength UVB and UVC radiation. Thin layers of clay, rock or meteorite material were shown to be only successful in UV-shielding, if they are in direct contact with the spores. On Mars the UV radiation climate is similar to that of the early Earth before the development of a protective ozone layer in the atmosphere by the appearance of the first aerobic photosynthetic bacteria. The interference of Martian soil components and the intense and nearly unfiltered Martian solar UV radiation with spores of B. subtilis will be tested with a new BIOPAN experiment, MARSTOX. Different types of Mars soil analogues will be used to determine on one hand their potential toxicity alone or in combination with solar UV (phototoxicity) and on the other hand their UV protection capability. Two sets of samples will be placed under different cut-off filters used to simulate the UV radiation climate of Mars and Earth. After exposure in space the survival of and mutation induction in the spores will be analyzed at the DLR, together with parallel samples from the corresponding ground control experiment performed in the laboratory. This experiment will provide new insights into the principal limits of life and its adaptation to environmental extremes on Earth or other planets which and will also have implications for the potential for the

  2. Biological space experiments for the simulation of Martian conditions: UV radiation and Martian soil analogues.

    PubMed

    Rettberg, P; Rabbow, E; Panitz, C; Horneck, G

    2004-01-01

    The survivability of resistant terrestrial microbes, bacterial spores of Bacillus subtilis, was investigated in the BIOPAN facility of the European Space Agency onboard of Russian Earth-orbiting FOTON satellites (BIOPAN I -III missions). The spores were exposed to different subsets of the extreme environmental parameters in space (vacuum, extraterrestrial solar UV, shielding by protecting materials like artificial meteorites). The results of the three space experiments confirmed the deleterious effects of extraterrestrial solar UV radiation which, in contrast to the UV radiation reaching the surface of the Earth, also contains the very energy-rich, short wavelength UVB and UVC radiation. Thin layers of clay, rock or meteorite material were shown to be only successful in UV-shielding, if they are in direct contact with the spores. On Mars the UV radiation climate is similar to that of the early Earth before the development of a protective ozone layer in the atmosphere by the appearance of the first aerobic photosynthetic bacteria. The interference of Martian soil components and the intense and nearly unfiltered Martian solar UV radiation with spores of B. subtilis will be tested with a new BIOPAN experiment, MARSTOX. Different types of Mars soil analogues will be used to determine on one hand their potential toxicity alone or in combination with solar UV (phototoxicity) and on the other hand their UV protection capability. Two sets of samples will be placed under different cut-off filters used to simulate the UV radiation climate of Mars and Earth. After exposure in space the survival of and mutation induction in the spores will be analyzed at the DLR, together with parallel samples from the corresponding ground control experiment performed in the laboratory. This experiment will provide new insights into the principal limits of life and its adaptation to environmental extremes on Earth or other planets which and will also have implications for the potential for the

  3. Assessing the evolution of soil moisture and vegetation conditions during the 2012 United States flash drought

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examines the evolution of several model-based and satellite-derived drought metrics sensitive to soil moisture and vegetation conditions during the extreme flash drought event that impacted major agricultural areas across the central U.S. during 2012. Standardized anomalies from the remo...

  4. NATIONAL RESULTS FROM THE 2011 NATIONAL WETLAND CONDITION ASSESSMENT (NWCA) SOILS ANALYSIS

    EPA Science Inventory

    In 2011, US Environmental Protection Agency conducted the first National Wetland Condition Assessment (NWCA). Field crews conducted one-day surveys of over 1000 wetlands across the contiguous United States. For every wetland sampled, soils were collected by layer (i.e., horizon)...

  5. Bacillus spp. from rainforest soil promote plant growth under limited nitrogen conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: The aim of this study was to evaluate effects of PGPR (Plant Growth Promoting Rhizobacteria) isolated from rainforest on different plants under limited nitrogen conditions. Methods and Results: Bacterial isolates from a Peruvian rainforest soil were screened for plant growth promoting effects...

  6. Exploring transport dynamics of "new" and "old" tracers under varying hydrologic conditions in structured soils

    NASA Astrophysics Data System (ADS)

    Bishop, Joshua; Callaghan, Michael; Mikulic, Danijela; Cey, Edwin

    2016-04-01

    Fine-grained, structured soils are prone to preferential flow along macropores that can enhance vertical migration of surface applied contaminants ("new" solutes) due to water bypassing the soil matrix. This same bypass phenomenon can also inhibit the flushing of in situ salt or other contaminants ("old" solutes), thereby hampering reclamation of previously impacted soils. In all cases, mass exchange between the soil matrix and macropores is a significant control on water and solute movement in the soil profile. The dynamics of these mass exchange processes and the associated transport of both new and old tracers were studied in field- and core-scale experiments on low permeability, macroporous soils. A multi-year investigation of new (DFBA) and old (Cl) tracer transport was completed on two 20 x 20 m test plots within a tile-drained field. Irrigation water was applied to one test plot, while the second plot served as an unirrigated control. Detailed monitoring, including wells, lysimeters, tensiometers, soil cores, tile drains, and electrical resistivity tomography, revealed a comprehensive picture of the hydraulic system response and distribution of chemical tracers over multiple field seasons. A large difference in solute transport within and between seasons was attributed to temporally varying hydrologic (water table and soil moisture) conditions, despite similar total volumes of water application. Time-varying soil hydraulic properties and soil macropore saturation were believed to play a major role, and were explored in more detail with large, intact soil monolith experiments. Two paired-core infiltration experiments were completed using the same volumes of irrigation water, but different irrigation rates and durations. The migration of new (Br, I, and dye) and old (Cl) tracers was monitored throughout the experiments, and the final tracer distribution was characterized by destructive sampling at the conclusion of irrigation. The spatial and temporal

  7. Electrokinetic remediation of a Cu-Zn contaminated red soil by controlling the voltage and conditioning catholyte pH.

    PubMed

    Zhou, Dong-Mei; Deng, Chang-Fen; Cang, Long; Alshawabkeh, Akram N

    2005-10-01

    Electrokinetics is an innovative technique for treating heavy metals contaminated soil, especially low pH soils such as the Chinese red soil (Udic Ferrisols). In this paper, a Cu-Zn contaminated red soil is treated by electrokinetics. When the Cu-Zn contaminated red soil was treated without control of catholyte pH during the electrokinetic treatment, the soil pH in the soil sections near cathode after the experiment was high above 6, which resulted in accumulation of large amounts of Cu and Zn in the soil sections with such high pH values. Compared to soil Cu, soil Zn was more efficiently removed from the soil by a controlled electrokinetic method. Application of lactic acid as catholyte pH conditioning solution caused an efficient removal of Cu and Zn from the soil. Increasing the electrolyte strength (salt concentration) of the conditioning solution further increased Cu removal, but did not cause a significant improvement for soil Zn. Soil Cu and Zn fractions after the electrokinetic treatments were analyzed using sequential extraction method, which indicated that Cu and Zn precipitation in the soil section closest to the cathode in the treatments without catholyte pH control limited their removal from the soil column. When the catholyte pH was controlled by lactic acid and CaCl(2), the soil Cu and Zn removal percentage after 554 h running reached 63% and 65%, respectively. Moreover, both the residual soil Cu and Zn concentrations were lower than 100 mg kg(-1), which is adequate and meets the requirement of the Chinese soil environmental quality standards. PMID:16202805

  8. [Response of mineralization of dissolved organic carbon to soil moisture in paddy and upland soils in hilly red soil region].

    PubMed

    Chen, Xiang-Bi; Wang, Ai-Hua; Hu, Le-Ning; Huang, Yuan; Li, Yang; He, Xun-Yang; Su, Yi-Rong

    2014-03-01

    Typical paddy and upland soils were collected from a hilly subtropical red-soil region. 14C-labeled dissolved organic carbon (14C-DOC) was extracted from the paddy and upland soils incorporated with 14C-labeled straw after a 30-day (d) incubation period under simulated field conditions. A 100-d incubation experiment (25 degrees C) with the addition of 14C-DOC to paddy and upland soils was conducted to monitor the dynamics of 14C-DOC mineralization under different soil moisture conditions [45%, 60%, 75%, 90%, and 105% of the field water holding capacity (WHC)]. The results showed that after 100 days, 28.7%-61.4% of the labeled DOC in the two types of soils was mineralized to CO2. The mineralization rates of DOC in the paddy soils were significantly higher than in the upland soils under all soil moisture conditions, owing to the less complex composition of DOC in the paddy soils. The aerobic condition was beneficial for DOC mineralization in both soils, and the anaerobic condition was beneficial for DOC accumulation. The biodegradability and the proportion of the labile fraction of the added DOC increased with the increase of soil moisture (45% -90% WHC). Within 100 days, the labile DOC fraction accounted for 80.5%-91.1% (paddy soil) and 66.3%-72.4% (upland soil) of the cumulative mineralization of DOC, implying that the biodegradation rate of DOC was controlled by the percentage of labile DOC fraction.

  9. Global Evaporation Estimates from SMAP Passive Microwave Soil Moisture Retrievals Using Conditional Sampling.

    NASA Astrophysics Data System (ADS)

    Vreugdenhil, M.; Entekhabi, D.; Konings, A. G.; Salvucci, G.; Hogan, P.

    2015-12-01

    Evaporation links the water, energy and carbon cycles over land yet even its climatology on global scale is not observed. Tower-based flux measurements are sparse and do not cover diverse biomes and climates. In the last decades, many strategies to derive evaporation based on remote sensing measurements have been developed. However, these methods are dependent on a variety of assumptions and auxiliary data, making them more prone to error propagation. A more data-driven method was developed by Salvucci (2001), who found that under statistical stationary conditions the expected change in soil moisture storage is zero when conditioned to a certain storage for a certain time interval. Consequently, using the water balance, precipitation conditionally averaged to the soil moisture storage is equal to the total loss: evaporation and drainage. Using only soil moisture and precipitation data as model inputs reduces the sources of uncertainty. In this presentation we provide the first estimates of global evaporation from NASA's Soil Moisture Active Passive mission by applying the conditional sampling method to passive microwave soil moisture time series and in situ precipitation data. The obtained evaporation estimates show a good correspondence to measured evaporation from eddy correlation towers over selected field sites. Subsequently, a simple approach is developed to directly estimate evaporation from SMAP soil moisture data. This approach enables the investigation of dynamics in evaporation during the dry-down after storms. The timing of the transition between the different stages of evaporation is assessed for different climates especially the transition from stage 1 to stage 2 evaporation; atmosphere limited evaporation to soil limited evaporation respectively. Investigations into the dynamics of unstressed evaporation and transpiration and the transition from stage 1 to stage 2 evaporation increases our understanding of water stress and soil desiccation. It also

  10. Dissipation kinetics of tetraconazole in three types of soil and water under laboratory condition.

    PubMed

    Alam, Samsul; Sengupta, Dwaipayan; Kole, Ramen Kumar; Bhattacharyya, Anjan

    2013-12-01

    Laboratory experiment was conducted to understand the persistence behavior of tetraconazole in three soils of West Bengal (alluvial, red lateritic, and coastal saline) and also in water maintained at three different pH (4.0, 7.0, and 9.2) conditions. Processed soil samples (100 g) were spiked at two treatment doses: 2.5 μg/g (T₁) and 5.0 μg/g (T₂). Double distilled buffered water (200 ml) was spiked at two treatment doses: 1.0 μg/ml (T₁) and 2.00 μg/ml (T₂). The tetraconazole dissipation followed first-order reaction kinetics and the residual half-life (T₁/₂) values in soil were found to be in the range of 66.9-77.2 days for T₁ and 73.4-86.0 days for T₂. The persistence increased in the order red lateritic > new alluvial > coastal saline. Interestingly, the red lateritic soil exhibited the lowest pH (5.56) and organic carbon (0.52%) content as compared to other two soils. However, the dissipation of tetraconazole in case of water was not pH dependant. The T₁/₂ values in water were in the range of 94 to 125 days. The study indicated the persistent nature of tetraconazole in soil and water.

  11. Observing soil water dynamics under two field conditions by a novel sensor system

    NASA Astrophysics Data System (ADS)

    Sheng, W.; Sun, Y.; Schulze Lammers, P.; Schumann, H.; Berg, A.; Shi, C.; Wang, C.

    2011-10-01

    SummarySufficiently available soil water is a basic requirement in agricultural production. Monitoring soil water dynamics (SWD) in the root zone is an optimal approach for managing a crop's growth. This study presents a novel sensor system that simultaneously measures volumetric soil water content (VSWC), apparent electrical conductivity (EC a) and soil temperature at two different soil depths (shallow: 16 cm; deep: 36 cm). For testing its feasibility in the field, two prototypes were installed, one in bare soil and the other in a sugar beet ( Beta vulgaris L.) field in the summer of 2010. Following a sequence of rainfall events randomly distributed over the experimental period, we observed distinct responses from the sensors at each monitored depth in both field conditions. In addition to the multi-parameter measurements, the novel sensor design includes a series of technical advantages such as solar-powered operation, wireless communication, and being relatively easy to install/remove. Thus, the developed wireless sensor system is promising for networked applications in precision farming.

  12. Antimony retention and release from drained and waterlogged shooting range soil under field conditions.

    PubMed

    Hockmann, Kerstin; Tandy, Susan; Lenz, Markus; Reiser, René; Conesa, Héctor M; Keller, Martin; Studer, Björn; Schulin, Rainer

    2015-09-01

    Many soils polluted by antimony (Sb) are subject to fluctuating waterlogging conditions; yet, little is known about how these affect the mobility of this toxic element under field conditions. Here, we compared Sb leaching from a calcareous shooting range soil under drained and waterlogged conditions using four large outdoor lysimeters. After monitoring the leachate samples taken at bi-weekly intervals for >1.5 years under drained conditions, two of the lysimeters were subjected to waterlogging with a water table fluctuating according to natural rainfall water infiltration. Antimony leachate concentrations under drained conditions showed a strong seasonal fluctuation between 110 μg L(-1) in summer and <40 μg L(-1) in winter, which closely correlated with fluctuations in dissolved organic carbon (DOC) concentrations. With the development of anaerobic conditions upon waterlogging, Sb in leachate decreased to 2-5 μg L(-1) Sb and remained stable at this level. Antimony speciation measurements in soil solution indicated that this decrease in Sb(V) concentrations was attributable to the reduction of Sb(V) to Sb(III) and the stronger sorption affinity of the latter to iron (Fe) (hydr)oxide phases. Our results demonstrate the importance of considering seasonal and waterlogging effects in the assessment of the risks from Sb-contaminated sites.

  13. Microbial inoculants and organic amendment improves plant establishment and soil rehabilitation under semiarid conditions.

    PubMed

    Mengual, Carmen; Schoebitz, Mauricio; Azcón, Rosario; Roldán, Antonio

    2014-02-15

    The re-establishment of autochthonous shrub species is an essential strategy for recovering degraded soils under semiarid Mediterranean conditions. A field assay was carried out to determine the combined effects of the inoculation with native rhizobacteria (Bacillus megaterium, Enterobacter sp, Bacillus thuringiensis and Bacillus sp) and the addition of composted sugar beet (SB) residue on physicochemical soil properties and Lavandula dentata L. establishment. One year after planting, Bacillus sp. and B. megaterium + SB were the most effective treatments for increasing shoot dry biomass (by 5-fold with respect to control) and Enterobacter sp + SB was the most effective treatments for increasing dry root biomass. All the treatments evaluated significantly increased the foliar nutrient content (NPK) compared to control values (except B. thuringiensis + SB). The organic amendment had significantly increased available phosphorus content in rhizosphere soil by 29% respect to the control. Enterobacter sp combined with sugar beet residue improved total N content in soil (by 46% respect to the control) as well as microbiological and biochemical properties. The selection of the most efficient rhizobacteria strains and their combined effect with organic residue seems to be a critical point that drives the effectiveness of using these biotechnological tools for the revegetation and rehabilitation of degraded soils under semiarid conditions. PMID:24463051

  14. Bench scale studies of the soil aeration process for bioremediation of petroleum hydrocarbons

    SciTech Connect

    Hinchee, R.E.; Arthur, M.

    1991-12-31

    An alternative to traditional hydrocarbon bioremediation is to pump air through unsaturated soils to create aerobic conditions and induce biodegradation. This study examines the effects of moisture and nutrient augmentation on biodegradation of petroleum hydrocarbons in aerated soils. Findings indicate that forced aeration, coupled with additions of nutrients and moisture, stimulate hydrocarbon-degrading microorganisms and present a feasible approach to bioremediation management.

  15. Cadmium and zinc interactions and their transfer in soil-crop system under actual field conditions.

    PubMed

    Nan, Zhongren; Li, Jijun; Zhang, Jianming; Cheng, Guodong

    2002-02-21

    The transfer of Cd and Zn from calcareous soils nearby a non-ferrous mining and smelting bases to the spring wheat (Triticum aestivum L.) and corn (Zea mays L.) tissues and the interactions between the two metals concerned were investigated under actual field conditions. Samples of soils and entire crops were randomly collected during harvest time in 1998 in the Baiyin region. The soil metal contents showed that the furrows had been polluted (mean values: 3.16 mg kg(-1) for Cd; 146.78 mg kg(-1) for Zn) and the significant spatial variation of the soil contamination existed here (ranges, Cd: 0.14-19.3 mg kg(-1); Zn: 43.5-565.0 mg kg(-1)). The translocation ratios of the two metals from soil to crop parts in the region studied were relatively lower and the order of the element transfer in different plant tissues was root > stem > grain. The transfer ratio of element Cd was lower than that of element Zn. Cd and Zn uptake by the crop structures could be best described by four models (P < 0.01): linear; exponential; quadratic; and cubic. Apart from a linear relationship between the element Cd in the corn grains and soils, models were generally non-lincar. An analysis of Cd-Zn interaction mechanism led to the conclusion that the effects of the two metals were synergistic to each other under field conditions, in which increasing Cd and Zn contents in soils could increase the accumulations of Zn or Cd in the two crops.

  16. Mosses influence phosphorus cycling in rich fens by driving redox conditions in shallow soils.

    PubMed

    Crowley, Katherine F; Bedford, Barbara L

    2011-09-01

    Mosses play an integral role in the hydrologic regimes of ecosystems where they cover the soil surface, and thus affect biogeochemical cycling of elements influenced by soil oxidation-reduction (redox) reactions, including the plant growth-limiting nutrients, nitrogen and phosphorus (P). In rich fens where P often limits plant growth, we hypothesized that feedbacks between mosses and redox conditions would determine P availability to shallow-rooted forb species that constitute much of these wetlands' unusually high plant species diversity. In a moss removal experiment in three fens, forb tissue P and microbial P were greater while anion exchange membrane (AEM) resin P was lower where mosses occurred than where they were removed, suggesting both higher availability and greater demand for P in moss-covered soils. Coupled physicochemical and biological mechanisms drove moss effects on P cycling, ultimately through effects on soil oxygenation or reduction: higher redox potential underlying mosses corresponded to greater microbial activity, phosphatase enzyme activity, and colonization by arbuscular mycorrhizal fungi (AMF), all of which can promote greater P availability to plants. These more oxidized soils stimulated: (1) greater microbial activity and root vigor; (2) correspondingly greater P demand via microbial uptake, forb uptake, and iron (Fe)-P reactions; and (3) greater P supply through soil and root phosphatase activity and AMF colonization. This work demonstrates that mosses improve vascular plant P acquisition by alleviating stresses caused by reducing conditions that would otherwise prevail in shallow underlying soils, thus providing a mechanism by which mosses facilitate plant species diversity in rich fens.

  17. Temporal and spatial development of surface soil conditions at two created riverine marshes.

    PubMed

    Anderson, Christopher J; Mitsch, William J; Nairn, Robert W

    2005-01-01

    The amount of time it takes for created wetlands to develop soils comparable to natural wetlands is relatively unknown. Surface soil changes over time were evaluated in two created wetlands (approximately 1 ha each) at the Olentangy River Wetland Research Park in Columbus, Ohio. The two wetlands were constructed in 1993 to be identical in size and geomorphology, and maintained to have the same hydrology. The only initial difference between the wetlands was that one was planted with native macrophytes while the other was not. In May 2004, soil samples were collected (10 yr and 2 mo after the wetlands were flooded) and compared to samples collected in 1993 (after the wetlands were excavated but before flooding) and 1995 (18 mo after the wetlands were flooded). In all three years, soils were split into surface (0-8 cm) and subsurface (8-16 cm) depths and analyzed for soil organic matter, total C, total P, available P, exchangeable cations, and pH. Soils in the two wetlands have changed substantially through sedimentation and organic accretion. Between 1993 and 1995, soils were most influenced by the deposition of senescent macroalgae, the mobilization of soluble nutrients, and the precipitation of CaCO(3). Between 1995 and 2004, soil parameters were influenced more by the deposition of organic matter from colonized macrophyte communities. Mean percent organic matter at the surface increased from 5.3 +/- 0.1% in 1993, 6.1 +/- 0.2% in 1995, to 9.5 +/- 0.2% in 2004. Mean total P increased from 493 +/- 18 microg g(-1) in 1993, 600 +/- 23 microg g(-1) in 1995, to 724 +/- 20 microg g(-1) in 2004. Spatial analyses of percent organic matter (a commonly used indicator of hydric soil condition) at both wetlands in 1993, 1995, and 2004 showed that soil conditions have become increasingly more variable. High spatial structure (autocorrelation) between data points was detected in 1993 and 2004, with data in 2004 exhibiting a much higher overall variance and narrower range of

  18. Temporal and spatial development of surface soil conditions at two created riverine marshes.

    PubMed

    Anderson, Christopher J; Mitsch, William J; Nairn, Robert W

    2005-01-01

    The amount of time it takes for created wetlands to develop soils comparable to natural wetlands is relatively unknown. Surface soil changes over time were evaluated in two created wetlands (approximately 1 ha each) at the Olentangy River Wetland Research Park in Columbus, Ohio. The two wetlands were constructed in 1993 to be identical in size and geomorphology, and maintained to have the same hydrology. The only initial difference between the wetlands was that one was planted with native macrophytes while the other was not. In May 2004, soil samples were collected (10 yr and 2 mo after the wetlands were flooded) and compared to samples collected in 1993 (after the wetlands were excavated but before flooding) and 1995 (18 mo after the wetlands were flooded). In all three years, soils were split into surface (0-8 cm) and subsurface (8-16 cm) depths and analyzed for soil organic matter, total C, total P, available P, exchangeable cations, and pH. Soils in the two wetlands have changed substantially through sedimentation and organic accretion. Between 1993 and 1995, soils were most influenced by the deposition of senescent macroalgae, the mobilization of soluble nutrients, and the precipitation of CaCO(3). Between 1995 and 2004, soil parameters were influenced more by the deposition of organic matter from colonized macrophyte communities. Mean percent organic matter at the surface increased from 5.3 +/- 0.1% in 1993, 6.1 +/- 0.2% in 1995, to 9.5 +/- 0.2% in 2004. Mean total P increased from 493 +/- 18 microg g(-1) in 1993, 600 +/- 23 microg g(-1) in 1995, to 724 +/- 20 microg g(-1) in 2004. Spatial analyses of percent organic matter (a commonly used indicator of hydric soil condition) at both wetlands in 1993, 1995, and 2004 showed that soil conditions have become increasingly more variable. High spatial structure (autocorrelation) between data points was detected in 1993 and 2004, with data in 2004 exhibiting a much higher overall variance and narrower range of

  19. Compartmental modeling of PAH transport in soil column experiments under variably-saturated flow conditions

    NASA Astrophysics Data System (ADS)

    Sartori, F.; Sericano, J. L.; Wade, T. L.; Mohanty, B. P.

    2012-12-01

    Knowledge about the mobilization of polycyclic aromatic hydrocarbons (PAH) from PAH-laden soils or sediments is important to understand their bioavailability, and ultimately assess the environmental risk of PAH transport from surface soils into the groundwater. The transport and kinetics of three PAH from a spiked soil layer (2-3 cm soil depth), Phenanthrene-d10 (1900 ng/g), Naphthalene-d8 (1500 ng/g), and Pyrene-d10 (1800 ng/g), were investigated by performing a series of 8 rainfall events during 25 days in two large, replicate soil columns (length: 35 cm; diameter: 14.5 cm; 1 Pore Volume [PV]=2.29 L) under variably-saturated flow conditions. The water-methanol displacing solutions were at volumetric fractions of 0.3 and 0.6 during day 1 (E1) through E8 and E12-E22, respectively. Soil matric potential (h) was monitored at 5-cm and 20-cm depth and volumetric water content (θ) at 12.5-cm and 27.5-cm depth. Soil solution was sampled at 5 cm- (n=46) and 27.5-cm depth (n=46), and the effluent at the bottom of the column (n=163). HYDRUS-1D was used for inverse modeling of h and θ data and to predict θ at specific times and soil depth increments. First-order kinetics, compartmental models describing the transfer of PAH from the soil compartment to the soil solution compartment (desorption) and vice versa (sorption), were used to estimate mass transfer rates (φs, sorption; φd, desorption; φe, elimination), PAH mass in each compartment, and partition coefficients (Kd). Phenanthrene breakthrough curve could be interpreted through a two-parameter, two-compartment model corresponding to the common two-site sorption model, whose parameter estimates (and 95% confidence intervals) were φd=2.72 (2.31, 3.19) PV-1 and φe=4.67 (3.82, 5.7 ) PV-1. Naphthalene breakthrough curve followed a simple one-compartment elimination model, φe=2.0 (1.9, 2.1) PV-1, and that of Pyrene a three-parameter, two-compartment model, φs=0.0454 (0.00853, 0.0603) PV-1, φd=0.165 (0.0319, 0.855) PV

  20. Partitioning of Evapotranspiration Into Soil Evaporation and Plant Transpiration Using Isotopes of Water in Controlled Conditions

    NASA Astrophysics Data System (ADS)

    Rothfuss, Y.; Bariac, T.; Braud, I.; Biron, P.; Richard, P.; Canale, L.; Durand, J.; Gaudet, J.

    2007-12-01

    Rainfall recycling by evapotranspiration from continental surfaces is certainly the most unknown component of the global water cycle. This is due to the large variability of rainfall as well as the heterogeneity of these continental surfaces, both in time and space. Traditional measuring methods such as sap flow, micro lysimeter, water and energy balance estimation (Bowen ratio, eddy correlation) have been used since the 70s for a monitoring of real evapotranspiration fluxes over crops and others plant covers. A complementary method consists in using isotopic biogeochemistry. When making specific hypothesis, it is possible to identify and quantify the different sources of the atmospheric water vapour (vegetation and soil at different scales). Analysis of the heavy stable isotopic ratios of water in both liquid and vapour phases: 18O and 2H can allow determining the history of the water in the soil since the last rainfall event (infiltration, re-evaporation) or the root extraction depths. Field campaigns measurements (plants and soils), interpreted using the Keeling Plot method allowed some progress in the partition between evaporation and transpiration understanding. But the experimental design is not sufficient to mechanistically describe the water processes involved. The study of all the interactions is difficult due to the large number of controlling variables describing climate, vegetation and soil characteristics. A monolith experiment (including soil and growing plant) was carried out in a reactor called RUBIC (Reactor Used for Continental Isotopic Biogeochemistry, Bariac et al., Geochim. Cosmochim. Acta., 1991). Controlled conditions allowed a monitoring and regulation of climatic parameters (net radiation, air temperature, vapour pressure deficit, CO2 partial pressure, and wind speed). It was also necessary to fix soil (structure, texture, and water content) and vegetation (specie and seeding density) parameters. The collected data allow us to improve our

  1. A Lagrangian model for soil water dynamics during rainfall-driven conditions

    NASA Astrophysics Data System (ADS)

    Zehe, Erwin; Jackisch, Conrad

    2016-09-01

    Within this study we propose a stochastic approach to simulate soil water dynamics in the unsaturated zone by using a non-linear, space domain random walk of water particles. Soil water is represented by particles of constant mass, which travel according to the Itô form of the Fokker-Planck equation. The model concept builds on established soil physics by estimating the drift velocity and the diffusion term based on the soil water characteristics. A naive random walk, which assumes all water particles to move at the same drift velocity and diffusivity, overestimated depletion of soil moisture gradients compared to a Richards solver. This is because soil water and hence the corresponding water particles in smaller pore size fractions are, due to the non-linear decrease in soil hydraulic conductivity with decreasing soil moisture, much less mobile. After accounting for this subscale variability in particle mobility, the particle model and a Richards solver performed highly similarly during simulated wetting and drying circles in three distinctly different soils. Both models were in very good accordance during rainfall-driven conditions, regardless of the intensity and type of the rainfall forcing and the shape of the initial state. Within subsequent drying cycles the particle model was typically slightly slower in depleting soil moisture gradients than the Richards model. Within a real-world benchmark, the particle model and the Richards solver showed the same deficiencies in matching observed reactions of topsoil moisture to a natural rainfall event. The particle model performance, however, clearly improved after a straightforward implementation of rapid non-equilibrium infiltration, which treats event water as different types of particles, which travel initially in the largest pore fraction at maximum velocity and experience a slow diffusive mixing with the pre-event water particles. The proposed Lagrangian approach is hence a promising, easy

  2. Measurements of heat fluxes and soil moisture patterns in the field conditions

    NASA Astrophysics Data System (ADS)

    Sanda, M.; Snehota, M.; Haase, T.; Wild, J.

    2011-12-01

    New combined thermal and soil moisture unit coded TMS2 is presented. It is a prototype designed on good experience with TMS1. The device combines three thermometers for use approximately at -10, 0 and +15 cm relative to soil surface when installed vertically. Soil moisture measurement is performed based on time domain transmission (TDT) principle for the full range of soil moisture. Presented new version incorporates lifetime power supply for approximately 5 year operation and life time permanent data storage (0.5 mil logs) if values are acquired every 10 minutes. Lifetime operation log accompanies lifetime data storage with lockable data blocks. Data are retrieved by contact portable pocket collector. Both vertical/surface or buriable/subsurface installation is possible thanks to additional communication interface on demand. Original model TMS1, proved durability in harsh outdoor environment with good functioning in wet conditions withstanding mechanical destruction. Extended testing in the sandstone area of the National Park Bohemian Switzerland, Czech Republic is performed since 2009 by the Institute of Botany of the ASCR. Results of long-term measurement at hundreds of localities are successfully used for i) evaluation of species-specific environmental requirements (for different species of plants, bryophytes and fungi) and ii) extrapolation of microclimatic conditions over large areas of rugged sandstone relief with assistance of accurate, LiDAR based, digital terrain model. TMS1 units are also applied for continuous measurement of temperature and moisture of coarse woody debris, which serves as an important substrate for establishment and growth of seedlings and is thus crucial for natural regeneration of many forest ecosystems. The TMS1 sensors have been tested and calibrated in soil laboratories of Czech Technical University in Prague for three soil materials: arenic cambisol, podzol and quartz sand, showing good linearity and minor influence of the

  3. Integrating legacy soil information in a Digital Soil Mapping approach based on a modified conditioned Latin Hypercube Sampling design

    NASA Astrophysics Data System (ADS)

    Stumpf, Felix; Schmidt, Karsten; Behrens, Thorsten; Schoenbrodt-Stitt, Sarah; Scholten, Thomas

    2014-05-01

    One crucial component of a Digital Soil Mapping (DSM) framework is outlined by geo-referenced soil observations. Nevertheless, highly informative legacy soil information, acquired by traditional soil surveys, is often neglected due to lacking accordance with specific statistical DSM designs. The focus of this study is to integrate legacy data into a state-of-the-art DSM approach, based on a modified conditioned Latin Hypercube Sampling (cLHS) design and Random Forest. Furthermore, by means of the cLHS modification the scope of actually unique cLHS sampling locations is widened in order to compensate limited accessability in the field. As well, the maximally stratified cLHS design is not diluted by the modification. Exemplarily the target variables of the modelling are represented by sand and clay fractions. The study site is a small mountainous hydrological catchment of 4.2 km² in the reservoir of the Three Gorges Dam in Central China. The modification is accomplished by demarcating the histogram borders of each cLHS stratum, which are based on the multivariate cLHS feature space. Thereby, all potential sample locations per stratum are identified. This provides a possibility to integrate legacy data samples that match one of the newly created sample locations, and flexibility with respect to field accessibility. Consequently, six legacy data samples, taken from a total sample size of n = 30 were integrated into the sampling design and for all strata several potential sample locations are identified. The comparability of the modified and standard cLHS data sets is approved by (i) identifying their feature space coverage with respect to the cLHS stratifying variables, and (ii) by assessing the Random Forest accuracy estimates.

  4. Testing of Icy-Soil Sample Delivery in Simulated Martian Conditions (Animation)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation

    This movie clip shows testing under simulated Mars conditions on Earth in preparation for NASA's Phoenix Mars Lander using its robotic arm for delivering a sample to the doors of a laboratory oven.

    The icy soil used in the testing flowed easily from the scoop during all tests at Martian temperatures. On Mars, icy soil has stuck to the scoop, a surprise that may be related to composition of the soil at the landing site.

    This testing was done at Honeybee Robotics Spacecraft Mechanisms Corp., New York, which supplied the Phoenix scoop.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASAaE(TM)s Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. Microhabitat Effects on N2O Emissions from Floodplain Soils under Controlled Conditions

    NASA Astrophysics Data System (ADS)

    Ley, Martin; Lehmann, Moritz F.; Niklaus, Pascal A.; Kuhn, Thomas; Luster, Jörg

    2016-04-01

    Semi-terrestrial soils such as floodplain soils are considered to be potential hotspots of nitrous oxide (N2O) emissions. The quantitative assessment of N2O release from these hotspots under field conditions, and of the microbial pathways that underlie net N2O production (ammonium oxidation, nitrifier-denitrification, and denitrification) is challenging because of their high spatial and temporal variability. The production and consumption of N2O appears to be linked to the presence or absence of micro-niches, providing specific conditions that may be favorable to either of the relevant microbial pathways. Flood events have been shown to trigger moments of enhanced N2O emission through a close coupling of niches with high and low oxygen availabilities. This coupling might be modulated by microhabitat effects related to soil aggregate formation, root soil interactions and the degradation of organic matter accumulations. In order to assess how these factors can modulate N2O production and consumption under simulated flooding/drying conditions, we have set up a mesocosm experiment with N-rich floodplain soils comprising different combinations of soil aggregate size classes and inert matrix material. These model soils were either planted with basket willow (Salix viminalis L.), mixed with leaf litter, or left untreated. Throughout a simulated flood event, we repeatedly measured the net N2O production rate. In addition, soil water content, redox potential, as well as C and N substrate availability were monitored. In order to gain insight into the sources of, and biogeochemical controls on N2O production, we also measured the bulk δ15N signature of the produced N2O, as well as its intramolecular 15N site preference (SP). In this presentation we focus on a period of enhanced N2O emission during the drying phase after 48 hrs of flooding. We will discuss the observed emission patterns in the context of possible treatment effects. Soils with large aggregates showed a

  6. Interactions with soils conditioned by different vegetation: a potential explanation of bromus tectorum L. invasion into salt-deserts?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasion by Bromus tectorum L. may condition the soil and increase nutrient availability. We hypothesized that nutrient poor soils of the arid Honey Lake Valley of northeastern California U.S.A., similar in physical and chemical properties, but conditioned by either B. tectorum, Krascheninniko...

  7. Root responses to soil physical conditions; growth dynamics from field to cell.

    PubMed

    Bengough, A Glyn; Bransby, M Fraser; Hans, Joachim; McKenna, Stephen J; Roberts, Tim J; Valentine, Tracy A

    2006-01-01

    Root growth in the field is often slowed by a combination of soil physical stresses, including mechanical impedance, water stress, and oxygen deficiency. The stresses operating may vary continually, depending on the location of the root in the soil profile, the prevailing soil water conditions, and the degree to which the soil has been compacted. The dynamics of root growth responses are considered in this paper, together with the cellular responses that underlie them. Certain root responses facilitate elongation in hard soil, for example, increased sloughing of border cells and exudation from the root cap decreases friction; and thickening of the root relieves stress in front of the root apex and decreases buckling. Whole root systems may also grow preferentially in loose versus dense soil, but this response depends on genotype and the spatial arrangement of loose and compact soil with respect to the main root axes. Decreased root elongation is often accompanied by a decrease in both cell flux and axial cell extension, and recent computer-based models are increasing our understanding of these processes. In the case of mechanical impedance, large changes in cell shape occur, giving rise to shorter fatter cells. There is still uncertainty about many aspects of this response, including the changes in cell walls that control axial versus radial extension, and the degree to which the epidermis, cortex, and stele control root elongation. Optical flow techniques enable tracking of root surfaces with time to yield estimates of two-dimensional velocity fields. It is demonstrated that these techniques can be applied successfully to time-lapse sequences of confocal microscope images of living roots, in order to determine velocity fields and strain rates of groups of cells. In combination with new molecular approaches this provides a promising way of investigating and modelling the mechanisms controlling growth perturbations in response to environmental stresses.

  8. Atrazine degradation by fungal co-culture enzyme extracts under different soil conditions.

    PubMed

    Chan-Cupul, Wilberth; Heredia-Abarca, Gabriela; Rodríguez-Vázquez, Refugio

    2016-01-01

    This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g(-1)) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 2(4) factorial experimental design. The Trametes maxima-Paecilomyces carneus co-culture extract contained more laccase activity and hydrogen peroxide (H2O2) content (laccase = 18956.0 U mg protein(-1), H2O2 = 6.2 mg L(-1)) than the T. maxima monoculture extract (laccase = 12866.7 U mg protein(-1), H2O2 = 4.0 mg L(-1)). Both extracts were able to degrade atrazine at 100%; however, the T. maxima monoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture with P. carneus (1.2 h). The FEE type (p = 0.03) and soil pH (p = 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by the T. maxima monoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strain T. maxima and its co-culture with P. carneus can efficiently and quickly degrade atrazine in clay-loam soils.

  9. Chloride and organic chlorine in forest soils: storage, residence times, and influence of ecological conditions.

    PubMed

    Redon, Paul-Olivier; Abdelouas, Abdesselam; Bastviken, David; Cecchini, Sébastien; Nicolas, Manuel; Thiry, Yves

    2011-09-01

    Recent studies have shown that extensive chlorination of natural organic matter significantly affects chlorine (Cl) residence time in soils. This natural biogeochemical process must be considered when developing the conceptual models used as the basis for safety assessments regarding the potential health impacts of 36-chlorine released from present and planned radioactive waste disposal facilities. In this study, we surveyed 51 French forested areas to determine the variability in chlorine speciation and storage in soils. Concentrations of total chlorine (Cl(tot)) and organic chlorine (Cl(org)) were determined in litterfall, forest floor and mineral soil samples. Cl(org) constituted 11-100% of Cl(tot), with the highest concentrations being found in the humus layer (34-689 mg Cl(org) kg(-1)). In terms of areal storage (53 - 400 kg Cl(org) ha(-1)) the mineral soil dominated due to its greater thickness (40 cm). Cl(org) concentrations and estimated retention of organochlorine in the humus layer were correlated with Cl input, total Cl concentration, organic carbon content, soil pH and the dominant tree species. Cl(org) concentration in mineral soil was not significantly influenced by the studied environmental factors, however increasing Cl:C ratios with depth could indicate selective preservation of chlorinated organic molecules. Litterfall contributions of Cl were significant but generally minor compared to other fluxes and stocks. Assuming steady-state conditions, known annual wet deposition and measured inventories in soil, the theoretical average residence time calculated for total chlorine (inorganic (Cl(in)) and organic) was 5-fold higher than that estimated for Cl(in) alone. Consideration of the Cl(org) pool is therefore clearly important in studies of overall Cl cycling in terrestrial ecosystems. PMID:21761932

  10. Benefits and limitations of pig slurry to reclaim bare mine soils under Mediterranean semiarid conditions

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Faz, Ángel; Acosta, Jose A.; Kabas, Sebla; Martínez-Martínez, Silvia; Ángeles Muñoz, M.

    2013-04-01

    In this study, the effects of pig slurry application on reclamation of mine soils from Cartagena-La Unión Mining District (SE Spain) were investigated in a field experiment. Exchangeable metals (Cd, Cu, Pb and Zn), total organic carbon, total nitrogen, soluble carbon, microbial biomass and three enzyme activities were periodically monitored during 67 days. In addition, one year after the application of the pig slurry, soil and developed vegetation was sampled. Results showed that only exchangeable Cd and Zn significantly decreased in the amended plots, mainly for Cd, with decreases of 98%. The rest of metals and chemical properties did not change with time after application of amendments, showing values not significantly different than those present before pig slurry application. Soluble carbon, microbial biomass carbon and the enzyme activities increased after the application of pig slurry. However, after various days these parameters started a decreasing trend until reaching values similar to the control from approximately day 25. Thus, mainly precipitation as phosphate from the waste was very effective for Cd immobilization. No increments were observed in soil organic carbon because the organic carbon applied with the slurry was too low to be significantly detected. Nonetheless, pig slurry is a good fertilizer owing to the high quantity of nutrients provided, needed to promote the development of vegetation. One year after application, a native vegetation cover (25-30%) was reached by spontaneous colonization. Triggered plant growth by the effect of amendment improved soil conditions, particularly by the help of the medium created by their rhizosphere systems. Increments in soil organic carbon and total nitrogen, and decreases in the exchangeable metals fraction concentration were observed in rhizospheric soils when compared to the bare soils. This improvement in soil quality mediated by vegetation was more efficient than the direct effect of the amendment. In

  11. Testing of the hydromechanical prediction model of soil erosion under the conditions of Georgia

    NASA Astrophysics Data System (ADS)

    Gogichaishvili, G. P.; Kirvalidze, D. R.; Gorjomeladze, O. L.

    2014-09-01

    A hydromechanical model for predicting water (rain-induced) soil erosion was tested on the experimental plots of the Research Institute of Tea and Subtropical Crops in Zendidi village (the Ajara Autonomous Republic) and the Sabashvili Institute of Soil Science, Agrochemistry, and Melioration in Khevi and Kitskhi villages (Upper Imeretia, Western Georgia). A comparison of factual and predicted values of rain-induced erosion for the plots with permanent black fallow showed that the model overestimated the average annual soil loss for the yellow-brown strongly eroded soil in Zendidi village by 23.22 t/ha (133%). This value ranged in different years from 18 to 1052%. For the plots with corn, the predicted value of annual erosion was by 16.94 t/ha higher than the factual value (overestimation of 488%). A comparison of factual and predicted values of rainfall erosion for the plots under sprinkling irrigation also showed that the predicted soil loss was higher than the factual one by 4.14-30.40 t/ha for corn, 6.76-11.14 t/ha for winter wheat, and 15.75-24.12 t/ha for the plots with stubble of winter wheat and barley. Thus, the hydromechanical model for predicting water erosion inadequately describes it under the conditions of Western Georgia and has to be refined.

  12. Biotite weathering in podzolic soil under conditions of a model field experiment

    NASA Astrophysics Data System (ADS)

    Sokolova, T. A.; Tolpeshta, I. I.; Topunova, I. V.

    2010-10-01

    The biotite changes in the 1-5 μm fraction after its occurrence in the F, H, AE, and E horizons of a pale-podzolic soil for five years under conditions of a model field experiment were assessed by X-ray diffraction analysis. It was found that the main changes of the biotite in all the horizons included the degradational transformation of its crystal lattice to interstratified mica-vermiculite structures and vermiculite. The intensity of this process gradually decreased from the F horizon down the profile in parallel with the decrease in the amount of roots and the abundance and activity of microbiota. Chloritized structures were present among the products of the biotite weathering in the H, AE, and E horizons; the degree of chloritization gradually increased from the H horizon to the E horizon. The main identified products of the biotite weathering in the AE and E horizons formed during the 5 years of the model experiment were identified in the clay and fine-silt fractions from these horizons of the native pale-podzolic soils. Therefore, the vermiculite, soil chlorite, and mixed-layer illite-vermiculite minerals in the soils studied could be considered as products of the recent soil functioning. The obtained results and literature data showed that the weathering of biotite resulted in the formation of K- and Al-buffer systems.

  13. Methanogenic archaea are globally ubiquitous in aerated soils and become active under wet anoxic conditions

    PubMed Central

    Angel, Roey; Claus, Peter; Conrad, Ralf

    2012-01-01

    The prototypical representatives of the Euryarchaeota—the methanogens—are oxygen sensitive and are thought to occur only in highly reduced, anoxic environments. However, we found methanogens of the genera Methanosarcina and Methanocella to be present in many types of upland soils (including dryland soils) sampled globally. These methanogens could be readily activated by incubating the soils as slurry under anoxic conditions, as seen by rapid methane production within a few weeks, without any additional carbon source. Analysis of the archaeal 16S ribosomal RNA gene community profile in the incubated samples through terminal restriction fragment length polymorphism and quantification through quantitative PCR indicated dominance of Methanosarcina, whose gene copy numbers also correlated with methane production rates. Analysis of the δ13C of the methane further supported this, as the dominant methanogenic pathway was in most cases aceticlastic, which Methanocella cannot perform. Sequences of the key methanogenic enzyme methyl coenzyme M reductase retrieved from the soil samples before incubation confirmed that Methanosarcina and Methanocella are the dominant methanogens, though some sequences of Methanobrevibacter and Methanobacterium were also detected. The global occurrence of only two active methanogenic archaea supports the hypothesis that these are autochthonous members of the upland soil biome and are well adapted to their environment. PMID:22071343

  14. Nitrous oxide: emission from soils during nitrification of fertilizer nitrogen.

    PubMed

    Bremner, J M; Blackmer, A M

    1978-01-20

    Nitrous oxide is released from soils to the atmosphere during nitrification of ammonium and ammonium-producing fertilizers under aerobic conditions as well as by denitrification of nitrate under anaerobic conditions. Emissions of nitrous oxide during nitrification of fertilizer nitrogen may be significant in regard to the potential threat of fertilizer-derived nitrous oxide to the stratospheric ozone layer. Such emissions can be greatly reduced through the use of nitrapyrin, which inhibits nitrification of ammonium by soil microorganisms.

  15. [Light response of Wisteria sinensis leaves physiological parameters under different soil moisture conditions].

    PubMed

    Xia, Jiang-bao; Zhang, Guang-can; Liu, Gang; Han, Wei; Chen, Jian; Liu, Xia

    2007-01-01

    With two years old Wisteria sinensis as test material, this paper measured the light response of its leaves net photosynthetic rate (Pn), transpiration rate (Tr) and water use efficiency (WUE) under different soil moisture conditions, aimed to ascertain the optimal soil moisture and light conditions of W. sinensis growth. The results showed that the Pn, Tr and WUE had evident threshold responses to the variations of soil moisture and light intensity. To maintain the normal growth and higher levels P. and WUE of W. sinensis, soil volumetric moisture content (Wr) and relative moisture content (Wv) should be within the range of 15.3%-26.5% and 46.4%-80.3%, and the optimal Wv and Wr were 23.3% and 70.6%, respectively. W. sineasis leaves had stronger adaptability to light conditions. When the photosynthetic active radiation (PAR) was 600-1600 micromol x m(-2) x s(-1), the Pn and WUE were at higher level, and the light saturation points of Pn and WUE were all at about 800-1000 x micromol x m(-2) x s(-1). The appearance of non-stomatal limit was significantly correlated with soil moisture and light intensity. When W, ranged from 18.4% to 26.5%, the decline of Pn was mainly caused by stomatal limit rather than PAR. Out of this range, Pn was obviously affected by PAR, and the critical turning point of PAR was observed with the change from stomatal limit to non-stomatal limit. The minimal values of Wv and Wr for the normal growth of W. sinensis were 11.9% and 36.1%, respectively, and the maximal PAR was 1000 micromol x m(-2) x s(-1), the critical point of detriment in leaf photosynthetic organ.

  16. Screening variability and change of soil moisture under wide-ranging climate conditions: Snow dynamics effects.

    PubMed

    Verrot, Lucile; Destouni, Georgia

    2015-01-01

    Soil moisture influences and is influenced by water, climate, and ecosystem conditions, affecting associated ecosystem services in the landscape. This paper couples snow storage-melting dynamics with an analytical modeling approach to screening basin-scale, long-term soil moisture variability and change in a changing climate. This coupling enables assessment of both spatial differences and temporal changes across a wide range of hydro-climatic conditions. Model application is exemplified for two major Swedish hydrological basins, Norrström and Piteälven. These are located along a steep temperature gradient and have experienced different hydro-climatic changes over the time period of study, 1950-2009. Spatially, average intra-annual variability of soil moisture differs considerably between the basins due to their temperature-related differences in snow dynamics. With regard to temporal change, the long-term average state and intra-annual variability of soil moisture have not changed much, while inter-annual variability has changed considerably in response to hydro-climatic changes experienced so far in each basin.

  17. Impact of soil moisture initial conditions on multi model summer predictions over mid-latitudes

    NASA Astrophysics Data System (ADS)

    Ardilouze, Constantin; Prodhomme, Chloé; Batté, Lauriane; Déqué, Michel

    2016-04-01

    Land surface initial conditions have been recognized as a potential source of predictability at seasonal time scales. As an example, results from GLACE-2 (phase 2 of the Global Land-Atmosphere Coupling Experiment) highlighted the impact of spring soil moisture in summer near-surface air temperature prediction over Europe and Northern America with global long-range forecast systems (Koster et al., 2011, van den Hurk et al.,2012). Yet, few studies have explored such an influence over a sufficient hindcast period to produce a robust quantitative assessment. In the framework of the FP7-SPECS project, dedicated experiments have been carried out with June-August hindcasts from 5 distinct Atmosphere Ocean Global Climate Models initialized either by realistic or climatological soil moisture conditions on May 1st. Realistic initialization leads to an improved 2-meter temperature prediction skill over parts of Europe in the multi model, particularly the Balkans peninsula which had been identified as a hot spot of soil moisture-atmosphere coupling (Seneviratne et al. 2006) However no improvement was found over North-American Great Plains in spite of the high potential of this region. Further analyses suggest that this lack of skill stems from a common shortcoming of the models. All of them tend to overestimate the positive feedback between soil moisture, temperature and precipitation with respect to the observations. Hence, tackling model systematic biases over the US Southern Great Plains appears as a necessary prerequisite for summer predictability enhancement.

  18. Biodegradation of select organic pollutants in soil columns under denitrifying conditions

    SciTech Connect

    Ramanand, K.; Balba, M.T.; Duffy, J.

    1995-12-31

    The majority of the biotreatability studies has been confined to laboratory flask assay level. However, these studies may not provide sufficient information for extrapolation to full-scale bioremediation. In this study, laboratory soil columns were used to closely simulate in-situ field conditions and predict the fate of certain aromatic compounds under denitrifying conditions. The soil columns, after sufficient acclimation period, metabolized toluene rapidly with concomitant nitrate consumption. Approximately 6.48 moles of nitrate was utilized per mole of toluene metabolized. This stoichiometry suggested that about 90% of the substrate was mineralized. Increasing the toluene loading rate from 23.4 to 93.5 mg/kg soil/day had no detrimental influence on the microbial degradative capabilities. When sufficient time was allowed for acclimation, the soil microbiota was able to cross-adapt to degrade other aromatic substrates including ethylbenzene, 2-, and 3-fluorobenzoic acid, and 2-, and 3- chlorophenol but was ineffective for degrading o-xylene, 2,3-dichlorophenol (DCP), 3,4-DCP and 3,5-DCP. These findings help explain the fate of these organic contaminants in anoxic environments. 17 refs., 7 figs., 1 tab.

  19. Formation of diphenylthioarsinic acid from diphenylarsinic acid under anaerobic sulfate-reducing soil conditions.

    PubMed

    Hisatomi, Shihoko; Guan, Ling; Nakajima, Mami; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2013-11-15

    Diphenylarsinic acid (DPAA) is a toxic phenylarsenical compound often found around sites contaminated with phenylarsenic chemical warfare agents, diphenylcyanoarsine or diphenylchloroarsine, which were buried in soil after the World Wars. This research concerns the elucidation of the chemical structure of an arsenic metabolite transformed from DPAA under anaerobic sulfate-reducing soil conditions. In LC/ICP-MS analysis, the retention time of the metabolite was identical to that of a major phenylarsenical compound synthesized by chemical reaction of DPAA and hydrogen sulfide. Moreover the mass spectra for the two compounds measured using LC/TOF-MS were similar. Subsequent high resolution mass spectral analysis indicated that two major ions at m/z 261 and 279, observed on both mass spectra, were attributable to C12H10AsS and C12H12AsSO, respectively. These findings strongly suggest that the latter ion is the molecular-related ion ([M+H](+)) of diphenylthioarsinic acid (DPTA; (C6H5)2AsS(OH)) and the former ion is its dehydrated fragment. Thus, our results reveal that DPAA can be transformed to DPTA, as a major metabolite, under sulfate-reducing soil conditions. Moreover, formation of diphenyldithioarsinic acid and subsequent dimerization were predicted by the chemical reaction analysis of DPAA with hydrogen sulfide. This is the first report to elucidate the occurrence of DPAA