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Sample records for aerobic soil microcosms

  1. 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...

  2. TRANSFORMATION OF CHIRAL POLLUTANTS IN SOIL AND SEDIMENT MICROCOSMS

    EPA Science Inventory

    The transformation rates and enantiomeric ratios of several chiral pollutants were determined in laboratory microcosms (25oC). Aerobic and anaerobic agricultural soil slurries were separately dosed with the following chiral pesticides: o,p'-DDT, o,p'-methoxychlor, cis-chlordane, ...

  3. ANAEROBIC SOIL DISINFESTATION IN MICROCOSMS OF TWO SANDY SOILS.

    PubMed

    Stremińska, M A; Runia, W T; Termorshuizen, A J; Feil, H; Van Der Wurff, A W G

    2014-01-01

    In recent years, anaerobic soil disinfestation (ASD) has been proposed as an alternative control method of soil-borne plant pathogens. It involves adding a labile carbon source, irrigating the soil to stimulate decomposition of organic material and then covering the soil with air-tight plastic to limit gas exchange. During the ASD process, soil microorganisms switch from aerobic to anaerobic metabolism. As a result, by-products of anaerobic metabolism are released into the soil environment such as various organic acids and gases. These by-products are reported to have a negative effect on survival of soil-borne plant pathogens. However, the efficacy of ASD to reduce soil-borne pathogens in practice may vary significantly. Therefore, we studied the efficacy of the ASD process in two different soils. In addition, it was investigated whether a pre-treatment with an anaerobic bacterial inoculum prior to ASD affected the efficacy of the process. Two sandy soils (dune sand and glacial sand) were inoculated in 2 L soil microcosms. We tested the efficacy of ASD treatment against the potato cyst nematode Globodera pallida. For each soil, three treatments were used: control treatment (no Herbie addition, aerobic incubation), ASD 1 (organic substrate addition, anaerobic incubation) and ASD 2 (organic substrate and anaerobic bacterial inoculum addition, anaerobic incubation). Soil microcosms were incubated in the dark at 20°C for two weeks. We observed that anaerobic soil disinfestation treatments were highly effective against Potato Cyst Nematode (PCN), with pathogen being eradicated totally in all but one ASD treatment (glacial sand ASD2) within two weeks. The relative abundance of Firmicutes (spore-forming bacteria, often fermentative) in total bacteria increased significantly in ASD treated soils. Numbers of these bacteria correlated positively with increased concentrations of acetic and butyric acids in soil water phase in ASD treatments. PMID:26084078

  4. The influence of iron on the biodegradation of benzene in soil microcosms

    SciTech Connect

    Poor, N.D.; Wheeler, E.; Novak, J.T.

    1996-12-31

    Iron was positively-correlated with benzene biodegradation rate in a statistically-significant multiple linear regression model of rates measured in aerobic soil microcosm experiments regressed with corresponding soil nitrate, phosphorus, iron, organic matter and sand content for 10 different previously uncontaminated Virginia subsurface soils. The addition of ferric chloride or ferric hydroxide to soil microcosms prepared with Alaga series sand and spiked with 10 mg/L initial benzene significantly increased the biodegradation rate in unamended experiments, but had no observable influence on biodegradation rates in experiments amended with ammonium phosphate and potassium phosphate. Unamended soil microcosms degraded 10 mg/L initial benzene in 10 days, iron-amended in 5 days, and nutrient-amended in 2 days.

  5. Aerobic Biotransformation of Fluorotelomer Thioether Amido Sulfonate (Lodyne) in AFFF-Amended Microcosms.

    PubMed

    Harding-Marjanovic, Katie C; Houtz, Erika F; Yi, Shan; Field, Jennifer A; Sedlak, David L; Alvarez-Cohen, Lisa

    2015-07-01

    The aerobic biotransformation pathways of 4:2, 6:2, and 8:2 fluorotelomer thioether amido sulfonate (FtTAoS) were characterized by determining the fate of the compounds in soil and medium microcosms amended with an aqueous film-forming foam (AFFF) solution. The biotransformation of FtTAoS occurred in live microcosms over approximately 40 days and produced 4:2, 6:2, and 8:2 fluorotelomer sulfonate (FtS), 6:2 fluorotelomer unsaturated carboxylic acid (FtUCA), 5:3 fluorotelomer carboxylic acid (FtCA), and C4 to C8 perfluorinated carboxylic acids (PFCAs). Two biotransformation products corresponding to singly and doubly oxygenated forms of 6:2 FtTAoS were also identified through high resolution mass spectrometry (MS) analysis and liquid chromatography tandem-MS. An oxidative assay was used to indirectly quantify the total concentration of polyfluorinated compounds and check the mass balance. The assay produced near complete mass recovery of FtTAoS after biotransformation, with 10% (mol/mol) of the amended FtTAoS accounted for in FtS, FtCA, and PFCA products. The transformation rates of identified products appear to be slow relative to FtTAoS, indicating that some intermediates may persist in the environment. This study confirms some of the sources of FtS and PFCAs in groundwater and soil at AFFF-impacted sites and suggests that fluorinated intermediates that are not routinely measured during the biotransformation of PFASs may accumulate. PMID:26042823

  6. Morphological Alteration and Survival of Burkholderia pseudomallei in Soil Microcosms.

    PubMed

    Kamjumphol, Watcharaporn; Chareonsudjai, Pisit; Taweechaisupapong, Suwimol; Chareonsudjai, Sorujsiri

    2015-11-01

    The resilience of Burkholderia pseudomallei, the causative agent of melioidosis, was evaluated in control soil microcosms and in soil microcosms containing NaCl or FeSO4 at 30°C. Iron (Fe(II)) promoted the growth of B. pseudomallei during the 30-day observation, contrary to the presence of 1.5% and 3% NaCl. Scanning electron micrographs of B. pseudomallei in soil revealed their morphological alteration from rod to coccoid and the formation of microcolonies. The smallest B. pseudomallei cells were found in soil with 100 μM FeSO4 compared with in the control soil or soil with 0.6% NaCl (P < 0.05). The colony count on Ashdown's agar and bacterial viability assay using the LIVE/DEAD(®) BacLight(™) stain combined with flow cytometry showed that B. pseudomallei remained culturable and viable in the control soil microcosms for at least 120 days. In contrast, soil with 1.5% NaCl affected their culturability at day 90 and their viability at day 120. Our results suggested that a low salinity and iron may influence the survival of B. pseudomallei and its ability to change from a rod-like to coccoid form. The morphological changes of B. pseudomallei cells may be advantageous for their persistence in the environment and may increase the risk of their transmission to humans. PMID:26324731

  7. Pyrosequencing Analysis Reveals High Population Dynamics of the Soil Microcosm Degrading Octachlorodibenzofuran

    PubMed Central

    Chen, Wei-Yu; Wu, Jer-Horng; Chang, Juu-En

    2014-01-01

    A deeper understanding of the microbial community structure is very important in bioremediation for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs). However, this has been insufficiently addressed in previous studies. To obtain more information, we pyrosequenced the V4/V5 regions of the 16S rRNA genes of bacterial communities transited from polluted soil to batch microcosms that rapidly degraded high concentrations of octachlorodibenzofuran (OCDF). The analysis results contained an average of 11,842 reads per sample, providing the first detailed description of bacterial communities associated with PCDD/Fs. The community composition markedly changed to be concomitant with the degradation of OCDF, indicating that a distinctive population structure developed rapidly in the microcosm. Although oxygen gas was provided weekly to the microcosm, the growth of potential degraders, Sphingomonas, Pseudomonas, Rhodococcus, and Clostridium, was observed, but in consistently low quantities. While anaerobic Sedimentibacter initially emerged as an abundant pioneer, several aerobic participants, such as the genera Brevundimonas, Pseudoxanthomonas, and Lysobacter, exhibited a large increase in their 16S rRNA gene copies within the timeframe, which showed a temporal population dynamic, and indicated their collaborative contributions to the degradation of OCDF under hypoxic conditions. These results have provided a deeper insight into the microbial community structure and population dynamics of the OCDF-degrading microcosm. PMID:25491754

  8. Aerobic Vinyl Chloride Metabolism in Groundwater Microcosms by Methanotrophic and Etheneotrophic Bacteria.

    PubMed

    Findlay, Margaret; Smoler, Donna F; Fogel, Samuel; Mattes, Timothy E

    2016-04-01

    Vinyl chloride (VC) is a carcinogen generated in groundwater by reductive dechlorination of chloroethenes. Under aerobic conditions, etheneotrophs oxidize ethene and VC, while VC-assimilators can use VC as their sole source of carbon and energy. Methanotrophs utilize only methane but can oxidize ethene to epoxyethane and VC to chlorooxirane. Microcosms were constructed with groundwater from the Carver site in MA containing these three native microbial types. Methane, ethene, and VC were added to the microcosms singly or as mixtures. In the absence of VC, ethene degraded faster when methane was also present. We hypothesized that methanotroph oxidation of ethene to epoxyethane competed with their use of methane, and that epoxyethane stimulated the activity of starved etheneotrophs by inducing the enzyme alkene monooxygenase. We then developed separate enrichment cultures of Carver methanotrophs and etheneotrophs, and demonstrated that Carver methanotrophs can oxidize ethene to epoxyethane, and that starved Carver etheneotrophs exhibit significantly reduced lag time for ethene utilization when epoxyethane is added. In our groundwater microcosm tests, when all three substrates were present, the rate of VC removal was faster than with either methane or ethene alone, consistent with the idea that methanotrophs stimulate etheneotroph destruction of VC. PMID:26918370

  9. Acidic sandy soil improvement with biochar - A microcosm study.

    PubMed

    Molnár, Mónika; Vaszita, Emese; Farkas, Éva; Ujaczki, Éva; Fekete-Kertész, Ildikó; Tolner, Mária; Klebercz, Orsolya; Kirchkeszner, Csaba; Gruiz, Katalin; Uzinger, Nikolett; Feigl, Viktória

    2016-09-01

    Biochar produced from a wide range of organic materials by pyrolysis has been reported as a means to improve soil physical properties, fertility and crop productivity. However, there is a lack of studies on the complex effects of biochar both on the degraded sandy soil physico-chemical properties and the soil biota as well as on toxicity, particularly in combined application with fertilizer and compost. A 7-week microcosm experiment was conducted to improve the quality of an acidic sandy soil combining variations in biochar types and amounts, compost and fertilizer application rates. The applied biochars were produced from different feedstocks such as grain husks, paper fibre sludge and wood screenings. The main purpose of the microcosm experiment was to assess the efficiency and applicability of different biochars as soil amendment prior to field trials and to choose the most efficient biochar to improve the fertility, biological activity and physical properties of acidic sandy soils. We complemented the methodology with ecotoxicity assessment to evaluate the possible risks to the soil as habitat for microbes, plants and animals. There was clear evidence of biochar-soil interactions positively affecting both the physico-chemical properties of the tested acidic sandy soil and the soil biota. Our results suggest that the grain husk and the paper fibre sludge biochars applied to the tested soil at 1% and 0.5 w/w% rate mixed with compost, respectively can supply a more liveable habitat for plants and soil living animals than the acidic sandy soil without treatment. PMID:26850860

  10. Inhibition of nitrate reduction by chromium (VI) in anaerobic soil microcosms

    SciTech Connect

    Kourtev, P. S.; Nakatsu, C. H.; Konopka, Allan

    2009-10-01

    Chromium (VI) is often found as a co-contaminant at sites polluted with organic compounds. We used microcosms amended with glucose or protein, nitrate and increasing concentrations of chromium to study nitrate reduction in Cr(VI) polluted soils. Organic carbon stimulated bacterial activity, but the addition of Cr(VI) caused a lag and then slower rates 5 of CO2 accumulation. Nitrate reduction only occurred after Cr(VI) had been reduced. Bacterial activity was again inhibited when Cr(VI) was added a second time; thus not all Cr-sensitive bacteria were removed in the first phase. Glucose and protein selected for relatively similar bacterial communities, as assayed by PCR-DGGE of the 16S rRNA gene; this selection was modified by the addition of 10 Cr(VI). Cr-resistant bacteria isolated from microcosms were closely related to members of Bacillus, Enterococcus and Propionibacterium sp. Our results indicate that carbon utilization and nitrate reduction in these soils in the presence of Cr(VI) are contingent upon the reduction of the added heavy metal by a limited subset of the bacterial community. The amount of Cr(VI) required to inhibit nitrate reduction was 10-fold less than for aerobic catabolism of the same 15 substrate. We hypothesize that the resistance level of a microbial process is directly related to the diversity of microbes capable of conducting it.

  11. SURVIVAL OF SALMONELLA TYPHIMURIUM IN FOUR SOIL MICROCOSMS AS AFFECTED BY SOIL TYPE AND INCUBATION TEMPERATURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Survival of Salmonella typhimurium was determined in sterile and non-sterile microcosms in four soil series (Brooksville, Leeper, Marietta, and Ruston) held at 10, 15, 25 and 35 degrees C. Exponential linear destruction was observed for S. typhimurium in non-sterile soil stored at all temperatures....

  12. Saprophytic growth of inoculated Frankia sp. in soil microcosms.

    PubMed

    Mirza, Babur S; Welsh, Allana; Hahn, Dittmar

    2007-12-01

    The potential of two Frankia strains to grow saprophytically was studied in nonsterile soil microcosms with ground leaf litter of Alnus glutinosa as the sole carbon and nitrogen sources. Strains Ag45/Mut15 and ArI3, which represent two taxonomic subgroups within the Alnus host infection group were inoculated alone, or together to investigate potential competition. Their growth was analyzed by in situ and dot-blot hybridization. A significant increase in cell numbers and filament length was observed during the first 6 weeks after inoculation for strain Ag45/Mut15, both alone and in mixed culture with strain ArI3, followed by a decrease until the end of the study after 12 weeks. The number of filaments remained unchanged. In contrast, the cell numbers and filament length of strain ArI3 were reduced significantly during the first 2 weeks and were undetectable for the remainder of the study. These results were comparable with those obtained in sterile mineral medium amended with leaf litter of A. glutinosa, although reductions in cell numbers and filament length were less pronounced than in soil microcosms. In concomitant control studies without leaf litter amendments for both experimental setups, filaments of both strains could only be detected immediately after inoculation. These results were matched in all experimental setups by concomitant shifts in the rRNA content of both strains, i.e., an immediate decline in the rRNA content for strain ArI3 after inoculation, and an increase in the rRNA content, followed by a late decline during incubation for strain Ag45/Mut15. These results demonstrated that Frankia strain Ag45/Mut15 could grow saprophytically in soil with complex carbon and nitrogen sources such as leaf litter, while the growth of strain ArI3 was not supported. PMID:17916077

  13. Carbazole degradation in the soil microcosm by tropical bacterial strains

    PubMed Central

    Salam, Lateef B.; Ilori, Matthew O.; Amund, Olukayode O.

    2015-01-01

    In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g) after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized) soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg), 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg−1 h−1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg−1 h−1. In native soil amended with carbazole (100 mg/kg), 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg−1 h−1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days) and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments. PMID:26691461

  14. The transformation of hexabromocyclododecane in aerobic and anaerobic soils and aquatic sediments.

    PubMed

    Davis, J W; Gonsior, S; Marty, G; Ariano, J

    2005-03-01

    The biological transformation of hexabromocyclododecane (HBCD), a brominated fire retardant commonly used in a variety of consumer goods, was investigated in aerobic and anaerobic soils and freshwater sediments. Soil, river water, and aquatic sediments were collected from several locations in the United States and transformation of HBCD was evaluated in the correspondingly composed microcosms based on the Organisation for Economic Co-Operation and Development (OECD) Test Guidelines 307 (Aerobic and Anaerobic Transformation in Soil) or 308 (Aerobic and Anaerobic Transformation in Aquatic Sediment Systems). Soil and sediment reaction mixtures, prepared under either aerobic or anoxic conditions, were dosed with HBCD at a concentration ranging from approximately 10 to 80 ng/g dry weight. The soils and sediments were then placed at 20 degrees C for approximately 4 months and the concentration of HBCD in the microcosms was determined at selected time intervals utilizing high-performance liquid chromatography-mass spectrometry (LC-MS). HBCD loss was observed in both the aerobic and anaerobic soils and sediments although the rates were appreciable faster under anoxic conditions. Biologically mediated transformation processes (i.e., biotransformation) accelerated the rate of loss of HBCD when compared to the biologically inhibited (i.e., autoclaved) soils and sediments. Biotransformation half-lives for HBCD were determined to be 63 and 6.9 days in the aerobic and anaerobic soils, respectively, while biotransformation half-lives for HBCD in the two river systems ranged from 11 to 32 days and 1.1 to 1.5 days under aerobic and anaerobic conditions, respectively. Brominated degradation products were not detected in any of the soils or sediments during the course of the study. PMID:15766961

  15. SOME EFFECTS OF CADMIUM ON CONIFEROUS FOREST SOIL AND LITTER MICROCOSMS

    EPA Science Inventory

    Description and criticism is given of a preliminary design and use of a soil/litter microcosm in which oxygen, temperature, and humidity are kept constant, and oxygen generation and carbon dioxide and heat evolution rates are monitored. Using four microcosms, one acting as a dead...

  16. Biodegradation of veterinary ionophore antibiotics in broiler litter and soil microcosms.

    PubMed

    Sun, Peizhe; Cabrera, Miguel L; Huang, Ching-Hua; Pavlostathis, Spyros G

    2014-01-01

    Ionophore antibiotics (IPAs) are polyether compounds used in broiler feed to promote growth and control coccidiosis. Most of the ingested IPAs are excreted into broiler litter (BL), a mixture of excreta and bedding material. BL is considered a major source of IPAs released into the environment as BL is commonly used to fertilize agricultural fields. This study investigated IPA biodegradation in BL and soil microcosms, as a process affecting the fate of IPAs in the environment. The study focused on the most widely used IPAs, monensin (MON), salinomycin (SAL), and narasin (NAR). MON was stable in BL microcosms at 24-72% water content (water/wet litter, w/w) and 35-60 °C, whereas SAL and NAR degraded under certain conditions. Factor analysis was conducted to delineate the interaction of water and temperature on SAL and NAR degradation in the BL. A major transformation product of SAL and NAR was identified. Abiotic reaction(s) were primarily responsible for the degradation of MON and SAL in nonfertilized soil microcosms, whereas biodegradation contributed significantly in BL-fertilized soil microcosms. SAL biotransformation in soil microcosms yielded the same product as in the BL microcosms. A new primary biotransformation product of MON was identified in soil microcosms. A field study showed that MON and SAL were stable during BL stacking, whereas MON degraded after BL was applied to grassland. The biotransformation product of MON was also detected in the top soil layer where BL was applied. PMID:24494860

  17. Hydrocarbon Specificity During Aerobic oil Biodegradation Revealed in Marine Microcosms With the use of Comprehensive, Two-Dimensional Gas Chromatography.

    NASA Astrophysics Data System (ADS)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Valentine, D. L.

    2008-12-01

    In 2003 the National Research Council reported more than 380 million gallons of oil is emitted into the ocean each year from natural seepage and as a result of anthropogenic activities. Many of the hydrocarbons making up this oil are persistent and toxic to marine life. Petroleum emitted into biologically sensitive areas can lead to environmental stress and ecosystem collapse. As a result many studies and a substantial amount of resources have been devoted to creating efficient and effective remediation tools and developing a better understanding of natural hydrocarbon weathering processes occurring in marine environments. The goal of this study is to elucidate patterns and extent of aerobic hydrocarbon degradation in marine sediments. In order to assess the specific molecular transformations occurring in petroleum emitted into oxic marine environments, we prepared microcosm experiments using sediments and seawater collected from the natural oil seeps offshore Coal Oil Point, California. Petroleum recovered from Platform Holly in the Santa Barbara Channel, was added to a sediment-seawater mixture and the microcosm bottles were allowed to incubate under aerobic conditions for slightly more than 100 days. Comprehensive, two-dimensional gas chromatography was employed in this study to quantify changes in the concentrations of individual hydrocarbon compounds because of the increased resolution and resolving power provided with this robust analytical method. We show significant hydrocarbon mass loss due to aerobic biodegradation for hundreds of tracked compounds in the microcosm bottles. The results shown here provide quantitative evidence for broad-scale metabolic specificity during aerobic hydrocarbon degradation in surface and shallow subsurface marine sediments.

  18. INTACT SOIL-CORE MICROCOSMS FOR EVALUATING THE FATE AND ECOLOGICAL IMPACT OF THE RELEASE OF GENETICALLY ENGINEERED MICROORGANISMS

    EPA Science Inventory

    Intact soil-core microcosms were studied to determine their applicability for evaluating the transport, survival and potential ecosystem effects of genetically engineered microorganisms before they are released into the environment. oi1-core microcosms were planted with wheat and...

  19. Phosphate release from seasonally flooded soils: a laboratory microcosm study.

    PubMed

    Young, E O; Ross, D S

    2001-01-01

    Phosphorus derived from agricultural practices has been targeted as a leading cause of water quality degradation in Lake Champlain. Mobilization of P from seasonally flooded agricultural soils is a concern. Using 14 soils from a research farm in New York's Champlain Valley, we characterized the available P status, extractable Fe and Al, P sorption capacities, and soluble phosphate release in flooded laboratory microcosms. Quantities of NH4-acetate available P ranged from 3 to 100 mg kg(-1) and fluoride-extractable P from 10 to 211 mg kg(-1). Flooding soils induced significant release of phosphate to the porewater over a 60- to 90-d period in 13 of the 14 soils studied. Porewater phosphate increases ranged from 2.2 to 27.0 times the initial phosphate concentrations. However, floodwater phosphate increases were much lower, with a maximum of 3.6 times the initial concentration. Average porewater phosphate concentrations over the flooding period ranged from 0.046 to 7.0 mg L(-1) and average floodwater P from 0.032 to 3.70 mg L(-1). Ammonium-acetate P and the degree of phosphorus saturation (DPS) were highly correlated with the average porewater and floodwater phosphate concentration. Average ratio of porewater to floodwater phosphate concentrations ranged from 1.0 to 3.3. Five soils that were lower in fluoride-extractable P had increasing porewater phosphate accompanied by increasing porewater Fe2+ and decreasing floodwater phosphate. Results suggest that P solubility and mobility were a function of both the available P status and redox cycling. PMID:11215671

  20. Microbial community analysis of switchgrass planted and unplanted soil microcosms displaying PCB dechlorination

    PubMed Central

    Liang, Yi; Meggo, Richard; Hu, Dingfei; Schnoor, Jerald L.; Mattes, Timothy E.

    2015-01-01

    Polychlorinated biphenyls (PCBs) pose potential risks to human and environmental health because they are carcinogenic, persistent and bioaccumulative. In this study we investigated bacterial communities in soil microcosms spiked with PCB 52, 77 and 153. Switchgrass (Panicum virgatum) was employed to improve overall PCB removal and redox cycling (i.e. sequential periods of flooding followed by periods of no flooding) was performed in an effort to promote PCB dechlorination. Lesser chlorinated PCB transformation products were detected in all microcosms, indicating the occurrence of PCB dechlorination. Terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis showed that PCB spiking, switchgrass planting and redox cycling affected the microbial community structure. Putative organohalide-respiring Chloroflexi populations, which were not found in unflooded microcosms, were enriched after two weeks of flooding in the redox-cycled microcosms. Sequences classified as Geobacter sp. were detected in all microcosms, and were most abundant in the switchgrass-planted microcosm spiked with PCB congeners. The presence of possible organohalide-respiring bacteria in these soil microcosms suggests they play a role in PCB dechlorination therein. PMID:25820643

  1. Introduction of anaerobic dechlorinating bacteria into soil slurry microcosms and nested-PCR monitoring.

    PubMed Central

    el Fantroussi, S; Mahillon, J; Naveau, H; Agathos, S N

    1997-01-01

    Desulfomonile tiedjei and Desulfitobacterium dehalogenans were chosen as model bacteria to demonstrate the introduction of an anaerobic microbia reductive dechlorination activity into nonsterile soil slurry microcosms by inoculation. De novo 3-chlorobenzoate dechlorination activity was established with the bacterium D. tiedjei in microcosms normally devoid of this dechlorination capacity. The addition of D. tiedjei to microcosms supplemented with 20 mM pyruvate as the cosubstrate resulted in total biotransformation of 1.5 mM 3-chlorobenzoate within 7 days. The introduction of the bacterium Desulfitobacterium dehalogenans into nonsterile microcosms resulted in a shortening of the period required for dechlorination activity to be established. In microcosms inoculated with Desulfitobacterium dehalogenans, total degradation of 6 mM 3-chloro-4-hydroxy phenoxyacetic acid (3-Cl-4-OHPA) was observed after 4 days in contrast to the result in noninoculated microcosms, where the total degradation of 3-Cl-4-OHPA by indigenous microorganisms was observed after 11 days. Both externally introduced bacterial strains were detected in soil slurry microcosms by a nested-PCR methodology. PMID:9023963

  2. Soil microcosm for testing the effects of chemical pollutants on soil fauna communities and trophic structure

    SciTech Connect

    Parmelee, R.W. . Dept. of Entomology); Wentsel, R.S.; Phillips, C.T.; Checkai, R.T. ); Simini, M. )

    1993-08-01

    A microcosm technique is presented that uses community and trophic-level analysis of soil nematodes and microarthropods to determine the effects of chemicals on soil systems. Forest soil was treated with either copper, p-nitrophenol, or trinitrotoluene. Nematodes were sorted into bacterivore, fungivore, herbivore, and omnivore-predator trophic groups, and a hatchling category. Microarthropods were sorted to the acarine suborders Prostigmata, Mesostigmata, and Oribatida; the insectan order Collembola; and a miscellaneous group. Omnivore-predator nematodes and meso-stigmatid and oribatid mites were the groups most sensitive to copper and were significantly reduced at levels as low as 100 [mu]g g[sup [minus]1] copper. Total nematode and microarthropod numbers declined above 200 [mu]g g[sup [minus]1] copper. Trophic structure analysis suggested that high sensitivity of nematode predators to intermediate levels of copper reduced predation on herbivore nematodes and resulted in greater numbers of nematodes compared to controls. p-Nitrophenol was very toxic to the nematode community, and all trophic groups were significantly reduced above 20 [mu]g g[sup [minus]1]. However, there was no effect of p-nitrophenol on microarthropods. Trinitrotoluene had no significant negative effect on total abundance of either groups of soil fauna, but oribatids were significantly reduced at 200 [mu]g g[sup [minus]1]. The results demonstrated that soil nematodes and microarthropods were sensitive indicators of environmental contaminants and that trophic-structure and community analysis has the potential to detect more subtle indirect effects of chemicals on soil food-web structure. The authors conclude that microcosms with field communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

  3. A soil microcosm to test the effects of pollutants on soil nematode and microarthropod communities

    SciTech Connect

    Parmelee, R.W.; Wentsel, R.S.; Checkai, R.T.; Phillips, C.T.; Bohlen, P.J.

    1995-12-31

    Previous studies have demonstrated that microcosms with field collected soil nematode and microarthropod communities are suitable model systems to detect effects of toxins on soil food web structure and function. The authors investigated the toxicity of copper, cadmium, malathion, and Aroclor 1254 to nematodes (total, bacterivores, fungivores, herbivores, omnivore-predators, hatchlings) and microarthropods (Prostigmata, Mesostigmata, Oribatida, Collembola, other arthropods). Nematodes were sensitive indicators of copper application, and total numbers were reduced at 100 {micro}g g{sup {minus}1}. Fungivore, bacterivore and omnivore-predators were the most susceptible trophic groups. Cadmium had no effects on either nematode or microarthropod communities. Microarthropods were more sensitive to malathion than nematodes, and total microarthropod abundance was lower than controls at 320 {micro}g g{sup {minus}1}. Prostigmatid mites and other arthropods were the most affected groups. Only the herbivore nematode trophic group was affected by malathion, and numbers did not decline until 1,280 {micro}g g{sup {minus}1}. Aroclor 1254 also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g g{sup {minus}1}, while there was no effect on nematodes. Prostigmatid and oribatid mites were the most susceptible groups to PCB application. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups need to be examined to fully evaluate the impact of chemicals on soil systems. The authors conclude that microcosms with field-collected communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

  4. Identification of active oxalotrophic bacteria by Bromodeoxyuridine DNA labeling in a microcosm soil experiments.

    PubMed

    Bravo, Daniel; Martin, Gaëtan; David, Maude M; Cailleau, Guillaume; Verrecchia, Eric; Junier, Pilar

    2013-11-01

    The oxalate-carbonate pathway (OCP) leads to a potential carbon sink in terrestrial environments. This process is linked to the activity of oxalotrophic bacteria. Although isolation and molecular characterizations are used to study oxalotrophic bacteria, these approaches do not give information on the active oxalotrophs present in soil undergoing the OCP. The aim of this study was to assess the diversity of active oxalotrophic bacteria in soil microcosms using the Bromodeoxyuridine (BrdU) DNA labeling technique. Soil was collected near an oxalogenic tree (Milicia excelsa). Different concentrations of calcium oxalate (0.5%, 1%, and 4% w/w) were added to the soil microcosms and compared with an untreated control. After 12 days of incubation, a maximal pH of 7.7 was measured for microcosms with oxalate (initial pH 6.4). At this time point, a DGGE profile of the frc gene was performed from BrdU-labeled soil DNA and unlabeled soil DNA. Actinobacteria (Streptomyces- and Kribbella-like sequences), Gammaproteobacteria and Betaproteobacteria were found as the main active oxalotrophic bacterial groups. This study highlights the relevance of Actinobacteria as members of the active bacterial community and the identification of novel uncultured oxalotrophic groups (i.e. Kribbella) active in soils. PMID:24033776

  5. FIELD CALIBRATION OF SOIL-CORE MICROCOSMS FOR EVALUATING FATE AND EFFECTS OF GENETICALLY ENGINEERED MICROORGANISMS IN TERRESTRIAL ECOSYSTEMS

    EPA Science Inventory

    Pacific Northwest Laboratory compared intact soil-core microcosms and the field for ecosystem structural and functional properties after the introduction of a model genetically engineered microorganism (GEM). This project used two distinct microbial types as model GEMs, Gram nega...

  6. Intact soil-core microcosms for evaluating the fate and ecological impact of the release of genetically engineered microorganisms

    SciTech Connect

    Fredrickson, J.K.; Van Voris, P.; Li, S.W. ); Bentjen, S.A. )

    1989-01-01

    Intact soil-core microcosms were studied to determine their applicability for evaluating the transport, survival, and potential ecosystem effects of genetically engineered microorganisms before they are released into the environment. Soil-core microcosms were planted with wheat and maize seeds and inoculated with Azospirillum lipoferum SpBr17 and SpRG20a Tn5 mutants, respectively. Microcosm leachate, rhizosphere soil, plant endorhizosphere, insects, and xylem exudate were sampled for A. lipoferum Tn5 mutant populations. A. lipoferum TN5 populations, determined by most-probable-number technique-DNA hybridization, varied from bellow detection to 10{sup 6} g of dry root{sup {minus}1} in the rhizosphere, with smaller populations detected in the endorhizosphere. Intact soil-core microcosms were found to maintain some of the complexities of the natural ecosystem and should be particularly useful for initial evaluations of the fate of plant-associated genetically engineered bacteria.

  7. Microcosm Studies to Evaluate Aerobic Cometabolism of Low Concentrations of 1,4-Dioxane by Isobutane-utilizing Microorganisms in the Presence of Chlorinated Solvent Co-contaminants

    NASA Astrophysics Data System (ADS)

    Rolston, H. M.; Azizian, M.; Hyman, M. R.; Semprini, L.

    2015-12-01

    Due to its use as a stabilizer for chlorinated solvents, 1,4-dioxane (1,4D), a probable human carcinogen, is a common co-contaminant in solvent spills at industrial and military sites and landfills. Its persistence in large groundwater plumes at low concentrations makes it a relevant candidate for in-situ bioremediation via cometabolism. Microcosm studies are being performed to evaluate the capability of aerobic microorganisms to cometabolize mixtures of 1,4D and chlorinated solvents, such as trichloroethylene (TCE), 1,1,1-trichloroethane (1,1,1TCA), and 1,1-dichloroethene (1,1DCE), with isobutane as the primary substrate. Microcosms were constructed using aquifer solids from Fort Carson, Colorado, a site contaminated with 1,4D and TCE, to assess the isobutane uptake and transformation of 1,4D and chlorinated solvents by microorganisms native to the site. Additional microcosms were augmented with Rhodococcus rhodochrous, a bacterium shown to cometabolize 1,4D and chlorinated solvents. Results indicate that native microcosms cometabolized 1,4D upon stimulation with isobutane after a lag period of about 15 days. TCE was also transformed, but at significantly slower rates. The presence of 1,4D and TCE at 500 and 300 ppb, respectively, did not inhibit the growth of native microorganisms on isobutane, with isobutane uptake and 1,4D transformation occurring simultaneously. Bioaugmented microcosms transformed 1,4D immediately after inoculation with R. rhodochrous. Tests in bioaugmented microorganisms indicated that the presence of TCE at low concentrations inhibits but does not block the transformation of 1,4D. Results from the microcosms will be used to design field tests to be performed at Fort Carson. Additional microcosm studies will compare the stimulation of native and bioaugmented microcosms and the transformation of mixtures of 1,4D, 1,1,1TCA and 1,1DCE. Molecular methods will analyze the monoxygenase enzymes expressed in the native and bioaugmented microcosms.

  8. Plasmid Transfer between Spatially Separated Donor and Recipient Bacteria in Earthworm-Containing Soil Microcosms

    PubMed Central

    Daane, L. L.; Molina, J.; Sadowsky, M. J.

    1997-01-01

    Most gene transfer studies have been performed with relatively homogeneous soil systems in the absence of soil macrobiota, including invertebrates. In this study we examined the influence of earthworm activity (burrowing, casting, and feeding) on transfer of plasmid pJP4 between spatially separated donor (Alcaligenes eutrophus) and recipient (Pseudomonas fluorescens) bacteria in nonsterile soil columns. A model system was designed such that the activity of earthworms would act to mediate cell contact and gene transfer. Three different earthworm species (Aporrectodea trapezoides, Lumbricus rubellus, and Lumbricus terrestris), representing each of the major ecological categories (endogeic, epigeic, and anecic), were evaluated. Inoculated soil microcosms, with and without added earthworms, were analyzed for donor, recipient, and transconjugant bacteria at 5-cm-depth intervals by using selective plating techniques. Transconjugants were confirmed by colony hybridization with a mer gene probe. The presence of earthworms significantly increased dispersal of the donor and recipient strains. In situ gene transfer of plasmid pJP4 from A. eutrophus to P. fluorescens was detected only in earthworm-containing microcosms, at a frequency of (symbl)10(sup2) transconjugants per g of soil. The depth of recovery was dependent on the burrowing behavior of each earthworm species; however, there was no significant difference in the total number of transconjugants among the earthworm species. Donor and recipient bacteria were recovered from earthworm feces (casts) of all three earthworm species, with numbers up to 10(sup6) and 10(sup4) bacteria per g of cast, respectively. A. trapezoides egg capsules (cocoons) formed in the inoculated soil microcosms contained up to 10(sup7) donor and 10(sup6) recipient bacteria per g of cocoon. No transconjugant bacteria, however, were recovered from these microhabitats. To our knowledge, this is the first report of gene transfer between physically

  9. TRACE ELEMENT RESEARCH USING CONIFEROUS FOREST SOIL/LITTER MICROCOSMS

    EPA Science Inventory

    Respirometers have been designed, constructed and to a limited extent, tested to maintain and measure production and/or consumption of biogenic heat and carbon dioxide production and oxygen consumption for extended periods of time in approximately 0.5 1 soil and/or litter microco...

  10. Responses of oxidation rate and microbial communities to methane in simulated landfill cover soil microcosms.

    PubMed

    He, Ruo; Ruan, Aidong; Jiang, Chenjing; Shen, Dong-Sheng

    2008-10-01

    CH4 oxidation capacities and microbial community structures developed in response to the presence of CH4 were investigated in two types of landfill cover soil microcosms, waste soil (fine material in stabilized waste) and clay soil. CH4 emission fluxes were lower in the waste soil cover over the course of the experiment. After exposure to CH4 flow for 120 days, the waste soil developed CH4 oxidation capacity from 0.53 to 11.25-13.48micromol CH4gd.w.(-1)h(-1), which was ten times higher than the clay soil. The topsoils of the two soil covers were observed dried and inhibited CH4 oxidation. The maximum CH4 oxidation rate occurred at the depth of 10-20cm in the waste soil cover (the middle layer), whereas it took place mainly at the depth of 20-30cm in the clay soil cover (the bottom layer). The amounts of the phospholipid fatty acid (PLFA) biomarks 16:1omega8c and 18:1omega8c for type I and II methanotrophs, respectively, showed that type I methanotrophic bacteria predominated in the clay soil, while the type II methanotrophic bacteria were abundant in the waste soil, and the highest population in the middle layer. The results also indicated that a greater active methanotrophic community was developed in the waste soil relative to the clay soil. PMID:18294841

  11. Natural transformation and availability of transforming DNA to Acinetobacter calcoaceticus in soil microcosms.

    PubMed Central

    Nielsen, K M; van Weerelt, M D; Berg, T N; Bones, A M; Hagler, A N; van Elsas, J D

    1997-01-01

    A small microcosm, based on optimized in vitro transformation conditions, was used to study the ecological factors affecting the transformation of Acinetobacter calcoaceticus BD413 in soil. The transforming DNA used was A. calcoaceticus homologous chromosomal DNA with an inserted gene cassette containing a kanamycin resistance gene, nptII. The effects of soil type (silt loam or loamy sand), bacterial cell density, time of residence of A. calcoaceticus or of DNA in soil before transformation, transformation period, and nutrient input were investigated. There were clear inhibitory effects of the soil matrix on transformation and DNA availability. A. calcoaceticus cells reached stationary phase and lost the ability to be transformed shortly after introduction into sterile soil. The use of an initially small number of A. calcoaceticus cells and nutrients, resulting in bacterial growth, enhanced transformation frequencies within a limited period. The availability of introduced DNA for transformation of A. calcoaceticus cells disappeared within a few hours in soil. Differences in transformation frequencies between soils were found; A. calcoaceticus cells were transformed at a higher rate and for a longer period in a silt loam than in a loamy sand. Physical separation of DNA and A. calcoaceticus cells had a negative effect on transformation. Transformation was also detected in nonsterile soil microcosms, albeit only in the presence of added nutrients and at a reduced frequency. These results suggest that chromosomal DNA released into soil rapidly becomes unavailable for transformation of A. calcoaceticus. In addition, strain BD413 quickly loses the ability to receive, stabilize, and/or express exogenous DNA after introduction into soil. PMID:9143126

  12. Field calibration of soil-core microcosms for evaluating fate and effects of genetically engineered microorganisms in terrestrial ecosystems

    SciTech Connect

    Bolton, H Jr; Fredrickson, J K; Bentjen, S A; Workman, D J; Li, S W; Thomas, J M

    1991-04-01

    Pacific Northwest Laboratory compared intact soil-core microcosms and the field for ecosystem structural and functional properties after the introduction of a model genetically engineered microorganism (GEM). This project used two distinct microbial types as model GEMs, Gram-negative Pseudomonas sp. RC1, which was an aggressive root colonizer, and Gram-positive Streptomyces lividans TK24. The model GEMs were added to surface soil in separate studies, with RC1 studied throughout the growth of winter wheat (Triticum aestivum), while TK24 was studied throughout a ten month period. Also, RC1 was used in studies conducted during two consecutive field seasons (1988 to 1990) to determine how year-to-year field variability influenced the calibration of microcosms with the field. The main conclusions of this research were that intact soil-core microcosms can be useful to simulate the field for studies of microbial fate and effects on ecosystem structural and functional properties. In general, microcosms in the growth chamber, which simulated average field variations, were similar to the field for most parameters or differences could be attributed to the great extremes in temperature that occurred in the field compared to the microcosms. Better controls of environmental variables including temperature and moisture will be necessary to more closely simulate the field for future use of microcosms for risk assessment. 126 refs., 13 figs., 12 tabs.

  13. Final Technical Report: Optimization and Directed, Natural Evolution of Biologically-Mediated Chromate Reduction in Subsurface Soil Microcosms

    SciTech Connect

    Thompson, Dorothea K; Wickham, Gene S; Layton, Alice C

    2012-07-27

    The U.S. Department of Energy (DOE) is faced with the complex challenge of remediating or containing the various mixed wastes present in the subsurface environments of numerous DOE sites. The development of scientifically grounded strategies for the effective management and reclamation of these contaminated sites requires fundamental knowledge on the composition, dynamics, and metabolic potential of indigenous microbial communities, which are of primary importance in the fate and transport of heavy metals and radionuclides in subsurface environments. To date, the complex effect of environmental (both geochemical and biological) parameters on the bioremediative potential of subsurface microbial populations is only partially understood; this is primarily because the majority of microbial ecological studies have focused only on a qualitative analysis of subsurface microbial diversity, while the impact of quantitative changes in microbial communities as a function of environmental factors has been ignored. The project described here directly addresses the need for a more comprehensive, molecular understanding of how microbial growth and activity quantitatively relate to mineral and contaminant biotransformation (Science Element: Subsurface Microbial Ecology and Community, Notice DE-FG02-06ER06-12). The proposed study uses a truly novel combination of standard molecular phylogenetic analyses, rRNA-targeted fluorescence in situ hybridization, and mass spectrometry (MS)-based proteomics to investigate the biological response to experimentally controlled conditions and the concomitant effect on chromate reduction in situ. This response will be characterized in terms of microbial community structure (principally, population number and spatial distribution) and community proteome dynamics. Towards this overarching goal, we will (1) set up aerobic and anaerobic laboratory microcosms derived from subsurface soil collected from a chromate [Cr(VI)]-contaminated DOE site, and

  14. Microcosm enrichment of biphenyl-degrading microbial communities from soils and sediments

    SciTech Connect

    Wagner-Doebler, I.; Bennasar, A.; Stroempl, C.; Bruemmer, I.; Eichner, C.; Grammel, I.; Moore, E.R.B.; Vancanneyt, M.

    1998-08-01

    A microcosm enrichment approach was employed to isolate bacteria which are representative of long-term biphenyl-adapted microbial communities. Growth of microorganisms was stimulated by incubating soil and sediment samples from polluted and nonpolluted sites with biphenyl crystals. After 6 months, stable population densities between 8 {times} 10{sup 9} and 2 {times} 10{sup 11} CFU/ml were established in the microcosms, and a large percentage of the organisms were able to grow on biphenyl-containing minimal medium plates. A total of 177 biphenyl-degrading strains were subsequently isolated and characterized by their ability to grow on biphenyl in liquid culture and to accumulate a yellow meta cleavage product when they were sprayed with dihydroxy-biphenyl. Isolates were identified by using a polyphasic approach, including fatty acid methyl ester (FAME) analysis, 16S rRNA gene sequence comparison, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, and genomic fingerprinting based on sequence variability in the 16S-23S ribosomal DNA intergenic spacer region. In all of the microcosms, isolates identified as Rhodococcus opacus dominated the cultivable microbial community, comprising a cluster of 137 isolates with very similar FAME profiles (Euclidean distances, <10) and identical 16S rRNA gene sequences.

  15. EVALUATION OF INTACT SOIL-CORE MICROCOSMS FOR DETERMINING POTENTIAL IMPACTS ON NUTRIENT DYNAMICS BY GENETICALLY ENGINEERED MICROORGANISMS

    EPA Science Inventory

    Nutrient export from intact soil-core microcosms in leachate or by plant uptake was evaluated as a means to assess the ecosystem impacts from the environmental release of genetically modified root-colonizing bacteria. ntact cores of two soil types, a Burbank sandy loam and an Pal...

  16. FATE OF TN5 MUTANTS OF ROOT GROWTH-INHIBITING PSEUDOMONAS SP. IN INTACT SOIL-CORE MICROCOSMS

    EPA Science Inventory

    Transposon Tn5 mutants of a wheat root growth-inhibiting nonfluorescent Pseudomonas sp. were inoculated into intact soil-core microcosms to determine the utility of intact soil cores for evaluating the fate and transport of microorganisms in agricultural ecosystems. ransposon Tn5...

  17. Effect of application solvents on heterotrophic and nitrifying populations in soil microcosms

    SciTech Connect

    Miller, J.L.; Sardo, M.A.; Thompson, T.L.; Miller, R.M.

    1997-03-01

    Agricultural practices may cause contamination of soil and ground water with a combination of organic compounds (pesticides and fuel) and nitrogen fertilizers. In coupled microcosm studies that monitored the mineralization of naphthalene and the nitrification of ammonia, it was observed that the solvent (dichloromethane) used to apply naphthalene to the soil inhibited nitrification, although there was no effect on naphthalene mineralization. Further studies were performed with a series of application solvents: methanol, acetonitrile, trichloromethane, and dichloromethane. Soil and solvent were allowed to equilibrate with ambient air for various times before capping and incubation of microcosms. Results indicated that dichloromethane equilibrated for 5 mins inhibited nitrification for at least 3 weeks relative to the control (water). Acetonitrile and trichloromethane similarly inhibited nitrification. Methanol and dichloromethane equilibrated for 60 mins also significantly delayed nitrification, although to a lesser extent. Inhibition of nitrification was not permanent, and nitrification activity was eventually restored in all systems tested. None of the solvents inhibited mineralization of the added carbon source. These results indicate that special care must be taken to ensure that applications solvents do not affect the activity of sensitive microbial populations, such as the nitrifiers, that may be part of a study.

  18. A Coexisting Fungal-Bacterial Community Stabilizes Soil Decomposition Activity in a Microcosm Experiment

    PubMed Central

    Ushio, Masayuki; Miki, Takeshi; Balser, Teri C.

    2013-01-01

    How diversity influences the stability of a community function is a major question in ecology. However, only limited empirical investigations of the diversity–stability relationship in soil microbial communities have been undertaken, despite the fundamental role of microbial communities in driving carbon and nutrient cycling in terrestrial ecosystems. In this study, we conducted a microcosm experiment to investigate the relationship between microbial diversity and stability of soil decomposition activities against changes in decomposition substrate quality by manipulating microbial community using selective biocides. We found that soil respiration rates and degradation enzyme activities by a coexisting fungal and bacterial community (a taxonomically diverse community) are more stable against changes in substrate quality (plant leaf materials) than those of a fungi-dominated or a bacteria-dominated community (less diverse community). Flexible changes in the microbial community composition and/or physiological state in the coexisting community against changes in substrate quality, as inferred by the soil lipid profile, may be the mechanism underlying this positive diversity–stability relationship. Our experiment demonstrated that the previously found positive diversity–stability relationship could also be valid in the soil microbial community. Our results also imply that the functional/taxonomic diversity and community ecology of soil microbes should be incorporated into the context of climate–ecosystem feedbacks. Changes in substrate quality, which could be induced by climate change, have impacts on decomposition process and carbon dioxide emission from soils, but such impacts may be attenuated by the functional diversity of soil microbial communities. PMID:24260368

  19. Influence of temperature and soil water content on bacterial, archaeal and denitrifying microbial communities in drained fen grassland soil microcosms.

    PubMed

    Stres, Blaz; Danevcic, Tjasa; Pal, Levin; Fuka, Mirna Mrkonjić; Resman, Lara; Leskovec, Simona; Hacin, Janez; Stopar, David; Mahne, Ivan; Mandic-Mulec, Ines

    2008-10-01

    In this study, microcosms were used to investigate the influence of temperature (4 and 28 degrees C) and water content (45% and 90% WHC) on microbial communities and activities in carbon-rich fen soil. Bacterial, archaeal and denitrifier community composition was assessed during incubation of microcosms for 12 weeks using terminal restriction fragment length polymorphism (T-RFLP) profiling of 16S rRNA and nitrous oxide reductase (nosZ) genes. In addition, microbial and denitrifier abundance, potential denitrification activity and production of greenhouse gases were measured. No detectable changes were observed in prokaryote or denitrifier abundance. In general, cumulatively after 12 weeks more carbon was respired at the higher temperature (3.7 mg CO(2) g(-1) soil), irrespective of the water content, whereas nitrous oxide production was greater under wet conditions (98-336 microg N(2)O g(-1) soil). After an initial lag phase, methane emissions (963 microg CH(4) g(-1) soil) were observed only under warm and wet conditions. T-RFLP analyses of bacterial 16S rRNA and nosZ genes revealed small or undetectable community changes in response to temperature and water content, suggesting that bacterial and denitrifying microbial communities are stable and do not respond significantly to seasonal changes in soil conditions. In contrast, archaeal microbial community structure was more dynamic and was strongly influenced by temperature. PMID:18710395

  20. Arbuscular-mycorrhizal networks inhibit Eucalyptus tetrodonta seedlings in rain forest soil microcosms.

    PubMed

    Janos, David P; Scott, John; Aristizábal, Catalina; Bowman, David M J S

    2013-01-01

    Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM) networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta) host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments) separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks-previously unrecognized as contributors to the ashbed effect-probably help to maintain the rain forest-savanna boundary. PMID:23460899

  1. Arbuscular-Mycorrhizal Networks Inhibit Eucalyptus tetrodonta Seedlings in Rain Forest Soil Microcosms

    PubMed Central

    Janos, David P.; Scott, John; Aristizábal, Catalina; Bowman, David M. J. S.

    2013-01-01

    Eucalyptus tetrodonta, a co-dominant tree species of tropical, northern Australian savannas, does not invade adjacent monsoon rain forest unless the forest is burnt intensely. Such facilitation by fire of seedling establishment is known as the "ashbed effect." Because the ashbed effect might involve disruption of common mycorrhizal networks, we hypothesized that in the absence of fire, intact rain forest arbuscular mycorrhizal (AM) networks inhibit E. tetrodonta seedlings. Although arbuscular mycorrhizas predominate in the rain forest, common tree species of the northern Australian savannas (including adult E. tetrodonta) host ectomycorrhizas. To test our hypothesis, we grew E. tetrodonta and Ceiba pentandra (an AM-responsive species used to confirm treatments) separately in microcosms of ambient or methyl-bromide fumigated rain forest soil with or without severing potential mycorrhizal fungus connections to an AM nurse plant, Litsea glutinosa. As expected, C. pentandra formed mycorrhizas in all treatments but had the most root colonization and grew fastest in ambient soil. E. tetrodonta seedlings also formed AM in all treatments, but severing hyphae in fumigated soil produced the least colonization and the best growth. Three of ten E. tetrodonta seedlings in ambient soil with intact network hyphae died. Because foliar chlorosis was symptomatic of iron deficiency, after 130 days we began to fertilize half the E. tetrodonta seedlings in ambient soil with an iron solution. Iron fertilization completely remedied chlorosis and stimulated leaf growth. Our microcosm results suggest that in intact rain forest, common AM networks mediate belowground competition and AM fungi may exacerbate iron deficiency, thereby enhancing resistance to E. tetrodonta invasion. Common AM networks–previously unrecognized as contributors to the ashbed effect–probably help to maintain the rain forest–savanna boundary. PMID:23460899

  2. Aerobic and microaerophilic actinomycetes of typical agropeat and peat soils

    NASA Astrophysics Data System (ADS)

    Zenova, G. M.; Gryadunova, A. A.; Pozdnyakov, A. I.; Zvyagintsev, D. G.

    2008-02-01

    A high number (from tens of thousands to millions of CFU/g of soil) of actinomycetes and a high diversity of genera were found in typical peat and agropeat soils. Agricultural use increases the number and diversity of the actinomycete complexes of the peat soils. In the peat soils, the actinomycete complex is represented by eight genera: Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, Saccharopolyspora, Saccharomonospora, and Microtetraspora. A considerable share of sporangial forms in the actinomycete complex of the peat soils not characteristic of the zonal soils was revealed. The number of actinomycetes that develop under aerobic conditions is smaller by 10-100 times than that of aerobic forms in the peat soils. Among the soil actinomycetes of the genera Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, and Microtetraspora, the microaerophilic forms were found; among the Saccharopolyspora and Saccharomonospora, no microaerophilic representatives were revealed.

  3. Fate of metal resistance genes in arable soil after manure application in a microcosm study.

    PubMed

    Xiong, Wenguang; Zeng, Zhenling; Zhang, Yiming; Ding, Xueyao; Sun, Yongxue

    2015-03-01

    Manure application contributes to the spread and persistence of metal resistance genes (MRGs) in the environment. We investigated the fate of copper (Cu) and zinc (Zn) resistance genes (pcoA, pcoD and zntA) in arable soil after Cu/Zn-containing manure application. Manure with or without addition of metals (Cu/Zn) was added in a soil microcosm over 2 months. Soil samples were collected for analysis on day 0, 30 and 60. The abundances of all MRGs (pcoA, pcoD and zntA) in manure group were significantly higher than those in untreated soil and manure+metals groups. All MRGs dissipated 1.2-1.3 times faster in manure group (from -90 ± 8% to -93 ± 7%) than those in manure+metals group (from -68 ± 8% to -78 ± 5%). The results indicated that manure from healthy pigs contributed to the occurrence of metals (Cu/Zn) and MRGs (pcoA, pcoD and zntA) in arable soil. The significant effects of manure application on the accumulation of pcoA, pcoD and zntA lasted for 1-2 months. Cu/Zn can slow down the dissipation of pcoA, pcoD and zntA after manure application. This is the first report to investigate the fate of MRGs in soil after manure application. PMID:25483373

  4. 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

  5. Introduction of mercury resistant bacterial strains to Hg(II) amended soil microcosms increases the resilience of the natural microbial community to mercury stress

    SciTech Connect

    de Lipthay, Julia R.; Rasmussen, Lasse D.; Serensen, Soren J.

    2004-03-17

    Heavy metals are among the most important groups of pollutant compounds, and they are highly persistent in the soil environment. Techniques that can be used for the remediation of heavy metal contaminated environments thus need to be evolved. In the present study we evaluated the effect of introducing a Hg resistance plasmid in subsurface soil communities. This was done in microcosms with DOE subsurface soils amended with 5-10 ppm of HgCl2. Two microcosms were set up. In microcosm A we studied the effect of adding strain S03539 containing either the Hg resistance conjugative plasmid, pJORD 70, or the Hg resistance mobilizable plasmid, pPB117. In microcosm B we studied the effect of adding strain KT2442 with and without pJORD70. For both microcosms, the effect on the resilience of the indigenous bacterial community as well as the effect on the soil concentration of Hg was evaluated.

  6. Persistence of pentolite (PETN and TNT) in soil microcosms and microbial enrichment cultures.

    PubMed

    Arbeli, Ziv; Garcia-Bonilla, Erika; Pardo, Cindy; Hidalgo, Kelly; Velásquez, Trigal; Peña, Luis; C, Eliana Ramos; Avila-Arias, Helena; Molano-Gonzalez, Nicolás; Brandão, Pedro F B; Roldan, Fabio

    2016-05-01

    Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT. PMID:26832872

  7. Application of electrical methods to measure microbial activity in soils: Preliminary microcosm results

    SciTech Connect

    Cox, B.L. Sweet, A.; Majer, E.

    1997-12-01

    The application of the geophysical technique known as self-potential to the measurement of microbial activity was tested on laboratory microcosms containing ferric iron and iron-reducing bacteria Shewanella alga BrY. Measurements of the electrical response of silver-coated copper electrodes distributed along a Teflon probe inserted into sterile and inoculated layers containing either ferric chloride, ferric citrate, or ferric oxide rich soil were recorded over hours or days. Strong electrical signals reached values more negative than {minus}400 mV for all types of inoculated ferric iron layers. Electric signals in sterile control layers, by contrast, rarely reached values more negative than {minus}150 mV. These preliminary experiments indicate that it may be possible to apply the self-potential geophysical method to monitor bioremediation in the field.

  8. Biodegradation of organic chemicals in soil/water microcosms system: Model development

    USGS Publications Warehouse

    Liu, L.; Tindall, J.A.; Friedel, M.J.; Zhang, W.

    2007-01-01

    The chemical interactions of hydrophobic organic contaminants with soils and sediments may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. In order to illustrate the recalcitrance of chemical to degradation on sites, a sorption mechanism of intraparticle sequestration was postulated to operate on chemical remediation sites. Pseudo-first order sequestration kinetics is used in the study with the hypothesis that sequestration is an irreversibly surface-mediated process. A mathematical model based on mass balance equations was developed to describe the fate of chemical degradation in soil/water microcosm systems. In the model, diffusion was represented by Fick's second law, local sorption-desorption by a linear isotherm, irreversible sequestration by a pseudo-first order kinetics and biodegradation by Monod kinetics. Solutions were obtained to provide estimates of chemical concentrations. The mathematical model was applied to a benzene biodegradation batch test and simulated model responses correlated well compared to measurements of biodegradation of benzene in the batch soil/water microcosm system. A sensitivity analysis was performed to assess the effects of several parameters on model behavior. Overall chemical removal rate decreased and sequestration increased quickly with an increase in the sorption partition coefficient. When soil particle radius, a, was greater than 1 mm, an increase in radius produced a significant decrease in overall chemical removal rate as well as an increase in sequestration. However, when soil particle radius was less than 0.1 mm, an increase in radius resulted in small changes in the removal rate and sequestration. As pseudo-first order sequestration rate increased, both chemical removal rate and sequestration increased slightly. Model simulation results showed that desorption resistance played an important role in the bioavailability of organic chemicals in porous

  9. Bioaugmentation of copper polluted soil microcosms with Amycolatopsis tucumanensis to diminish phytoavailable copper for Zea mays plants.

    PubMed

    Albarracín, Virginia Helena; Amoroso, María Julia; Abate, Carlos Mauricio

    2010-03-01

    Amycolatopsis tucumanensis DSM 45259, the strain of a recently recognized novel species of the genus Amycolatopsis with remarkable copper resistance, was used to bioaugment soil microcosms experimentally polluted with copper and for studying the ability of this strain to effectively diminish phytoavailable copper from soils. Our results demonstrated that A. tucumanensis was capable of profusely colonizing both, copper polluted and non-polluted soil. Copper bioimmobilization ability of A. tucumanensis on soil was assessed measuring the bioavailable copper in the soil solution extracted from polluted soil by using chemical and physical methods and, in this way, 31% lower amounts of the metal were found in soil solution as compared to non-bioaugmented soil. The results obtained when using Zea mays as bioindicator correlated well with the values obtained by the chemical and physical procedures: 20% and 17% lower tissue contents of copper were measured in roots and leaves, respectively. These data confirmed the efficiency of the bioremediation process using A. tucumanensis and at the same time proved that chemical, physical and biological methods for assessing copper bioavailability in soils were correlated. These results suggest a potential use of this strain at large scale in copper soil bioremediation strategies. To our knowledge, this work is the first to apply and to probe the colonization ability of an Amycolatopsis strain in soil microcosms and constitutes the first application of an Amycolatopsis strain on bioremediation of polluted soils. PMID:20163821

  10. Plutonium uptake by common soil aerobes

    NASA Astrophysics Data System (ADS)

    John, Seth; Rugglero, Christy; Hersman, Larry; Neu, Mary

    2000-07-01

    Radionuclide contamination in soils and groundwater poses a risk to both human and environmental health. The DOE has identified 12 sites with significant U contamination in the soils and ground water, and 10 sites with Pu contamination.1 It is important to study the interactions of common soil microbes with these radionuclides both to understand the environmental fate of these contaminants and to evaluate the potential of biological techniques to remediate contaminated soils and water.

  11. Determining the effects of pollutants on soil faunal communities and trophic structure using a refined microcosm system

    SciTech Connect

    Parmelee, R.W.; Phillips, C.T.; Checkai, R.T.; Bohlen, P.J.

    1997-06-01

    The authors used a refined microcosm technique to investigate the toxicity of copper, cadmium, malathion, and the polychlorinated biphenyl, to trophic groups of soil nematodes and to the microarthropod community. Comparisons of changes in nematode abundance in control soils through time indicated that day 7 was the most appropriate time to sample the microcosms after chemical application. Nematode abundance was reduced after exposure to copper at 100 {micro}g/g, with fungivore, bacterivore, and omnivore-predator nematodes being the most sensitive groups. Cadmium did not affect the nematode or microarthropod communities. Microarthropods were far more sensitive to malathion than were nematodes, and total microarthropod abundance was lower than controls at 400 {micro}g/g. Prostigmatid mites and other arthropods were the most affected groups. PCB also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g/g, with prostigmatid and oribatid mites exhibiting the highest susceptibility. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups should be examined to fully evaluate the biological impact of chemicals on soils. The authors conclude that microcosms with field-collected soil microfaunal communities offer high resolution of the ecotoxicologic effects of chemicals in complex soil systems.

  12. The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils

    PubMed Central

    Winder, Richard S.; Lamarche, Josyanne; Constabel, C. Peter; Hamelin, Richard C.

    2013-01-01

    The impacts of leaf litter from genetically modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins) were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE (denaturing gradient gel electrophoresis) detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β-Proteobacteria were proportionally more numerous at high-tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low-tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051). Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA (principal coordinate analyses) partitioned the fungal communities into three groups: (i) those with higher amounts of added tannin from both transformed and untransformed treatments, (ii) those corresponding to soils without litter, and (iii) those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in

  13. Linking Stoichiometric Homeostasis of Microorganisms with Soil Phosphorus Dynamics in Wetlands Subjected to Microcosm Warming

    PubMed Central

    Wang, Hang; Li, HongYi; Zhang, ZhiJian; Muehlbauer, Jeffrey D.; He, Qiang; Xu, XinHua; Yue, ChunLei; Jiang, DaQian

    2014-01-01

    Soil biogeochemical processes and the ecological stability of wetland ecosystems under global warming scenarios have gained increasing attention worldwide. Changes in the capacity of microorganisms to maintain stoichiometric homeostasis, or relatively stable internal concentrations of elements, may serve as an indicator of alterations to soil biogeochemical processes and their associated ecological feedbacks. In this study, an outdoor computerized microcosm was set up to simulate a warmed (+5°C) climate scenario, using novel, minute-scale temperature manipulation technology. The principle of stoichiometric homeostasis was adopted to illustrate phosphorus (P) biogeochemical cycling coupled with carbon (C) dynamics within the soil-microorganism complex. We hypothesized that enhancing the flux of P from soil to water under warming scenarios is tightly coupled with a decrease in homeostatic regulation ability in wetland ecosystems. Results indicate that experimental warming impaired the ability of stoichiometric homeostasis (H) to regulate biogeochemical processes, enhancing the ecological role of wetland soil as an ecological source for both P and C. The potential P flux from soil to water ranged from 0.11 to 34.51 mg m−2 d−1 in the control and 0.07 to 61.26 mg m−2 d−1 in the warmed treatment. The synergistic function of C-P acquisition is an important mechanism underlying C∶P stoichiometric balance for soil microorganisms under warming. For both treatment groups, strongly significant (p<0.001) relationships fitting a negative allometric power model with a fractional exponent were found between n-HC∶P (the specialized homeostatic regulation ability as a ratio of soil highly labile organic carbon to dissolved reactive phosphorus in porewater) and potential P flux. Although many factors may affect soil P dynamics, the n-HC∶P term fundamentally reflects the stoichiometric balance or interactions between the energy landscape (i.e., C) and flow of resources

  14. Linking stoichiometric homeostasis of microorganisms with soil phosphorus dynamics in wetlands subjected to microcosm warming.

    PubMed

    Wang, Hang; Li, Hongyi; Zhang, Zhijian; Muehlbauer, Jeffrey D; He, Qiang; Xu, Xinhua; Yue, Chunlei; Jiang, Daqian

    2014-01-01

    Soil biogeochemical processes and the ecological stability of wetland ecosystems under global warming scenarios have gained increasing attention worldwide. Changes in the capacity of microorganisms to maintain stoichiometric homeostasis, or relatively stable internal concentrations of elements, may serve as an indicator of alterations to soil biogeochemical processes and their associated ecological feedbacks. In this study, an outdoor computerized microcosm was set up to simulate a warmed (+5°C) climate scenario, using novel, minute-scale temperature manipulation technology. The principle of stoichiometric homeostasis was adopted to illustrate phosphorus (P) biogeochemical cycling coupled with carbon (C) dynamics within the soil-microorganism complex. We hypothesized that enhancing the flux of P from soil to water under warming scenarios is tightly coupled with a decrease in homeostatic regulation ability in wetland ecosystems. Results indicate that experimental warming impaired the ability of stoichiometric homeostasis (H) to regulate biogeochemical processes, enhancing the ecological role of wetland soil as an ecological source for both P and C. The potential P flux from soil to water ranged from 0.11 to 34.51 mg m(-2) d(-1) in the control and 0.07 to 61.26 mg m(-2) d(-1) in the warmed treatment. The synergistic function of C-P acquisition is an important mechanism underlying C∶P stoichiometric balance for soil microorganisms under warming. For both treatment groups, strongly significant (p<0.001) relationships fitting a negative allometric power model with a fractional exponent were found between n-HC∶P (the specialized homeostatic regulation ability as a ratio of soil highly labile organic carbon to dissolved reactive phosphorus in porewater) and potential P flux. Although many factors may affect soil P dynamics, the n-HC∶P term fundamentally reflects the stoichiometric balance or interactions between the energy landscape (i.e., C) and flow of resources

  15. 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. PMID:25086776

  16. Microcosm studies of the role of land plants in elevating soil carbon dioxide and chemical weathering

    NASA Astrophysics Data System (ADS)

    Baars, C.; Hefin Jones, T.; Edwards, Dianne

    2008-09-01

    A decrease in atmospheric carbon dioxide (CO2) concentration during the mid-Palaeozoic is postulated to have been partially the consequence of the evolution of rooted land plants. Root development increased the amount of carbonic acid generated by root respiration within soils. This led to increased chemical weathering of silicates and subsequent formation of carbonates, resulting in lower atmospheric CO2 concentrations. To test this assumption, analog (morphologically equivalent) plant species, ranging from those possessing no roots to those with complex rhizomatous rooting systems, were grown in trays within microcosms at ambient (360 ppm/0.37 mbar) and highly elevated (3500 ppm/3.55 mbar) atmospheric CO2 concentrations in a controlled environment facility. Substrate CO2 concentrations increased significantly under elevated atmospheric CO2, and Equisetum hyemale (L.). The latter is postulated to result from the effects of deeply rooted plants, elevated atmospheric CO2 concentrations, or both. Plants with simple or no rooting systems or the addition of dead organic matter as a substrate for microorganisms did not enhance substrate CO2 concentrations.

  17. Stimulation of anaerobic biodegradation of DDT and its metabolites in a muck soil: laboratory microcosm and mesocosm studies.

    PubMed

    Gohil, Hiral; Ogram, Andrew; Thomas, John

    2014-09-01

    The aim of this study was to evaluate the impact of selected electron donors and electron acceptors on the anaerobic biodegradation of DDT and its major metabolites in a muck soil with a long history of exposure to the pesticide. Loss of DDT was measured in anaerobic microcosms supplemented with H2, lactate, and acetate. The greatest loss of DDT (approximately 87 %) was observed in microcosms amended with lactate and no additional electron acceptor compared to the no additional electron donor or acceptor sets. An increase in measureable concentrations of DDx was observed in un-amended microcosms. In larger scale mesocosms, significant increases in dissolved organic carbon (DOC) corresponded with low redox potentials. Increases in DOC corresponded with sharp increases in measured concentrations of DDx, followed by a decrease in measured DDT concentrations in lactate-amended mesocosms. Our studies indicate that sorbed DDx is released upon anaerobic incubation, and that indigenous microorganisms capable of DDx degradation respond to lactate additions. Both the potential for release of sorbed DDx and the potential for biodegradation of DDx should be considered during remediation of DDx-contaminated organic soils at low redox potentials. PMID:24584703

  18. Growth promotion of Xanthium italicum by application of rhizobacterial isolates of Bacillus aryabhattai in microcosm soil.

    PubMed

    Lee, Sol; Ka, Jong-Ok; Song, Hong-Gyu

    2012-02-01

    This study was conducted using rhizobacteria, which are able to exert beneficial effects upon plant growth in the infertile soil collected from barren lakeside areas. Four strains of plant growth promoting bacteria were isolated from the rhizosphere of a common wild plant, Erigeron canadensis. Isolated strains LS9, LS11, LS12, and LS15 were identified as Bacillus aryabhattai by 16S rDNA sequence analysis. B. aryabhattai LS9, LS11, LS12, and LS15 could solubilize 577.9, 676.8, 623.6, and 581.3 mg/L of 0.5% insoluble calcium phosphate within 2 days of incubation. Production of indole acetic acid, a typical growth promoting phytohormone auxin, by strain LS15 was 471.3 mg/L in 2 days with the addition of auxin precursor L-tryptophan. All the strains also produced other phytohormones such as indole butyric acid, gibberellins, and abscisic acid, and strain LS15 showed the highest production rate of gibberellin (GA(3)), 119.0 μg/mg protein. Isolated bacteria were used in a microcosm test for growth of wild plant Xanthium italicum, which can be utilized as a pioneer plant in barren lands. Seed germination was facilitated, and the lengths of roots, and shoots and the dry weights of germinated seedlings after 16 days were higher than those of the uninoculated control plants. Root lengths of seedlings of X. italicum increased by 121.1% in LS11-treated samples after 16 days. This plant growth-promoting capability of B. aryabhattai strains may be utilized as an environmentally friendly means of revegetating barren lands, especially sensitive areas such as lakeside lands. PMID:22367936

  19. Soil and sediment bacteria capable of aerobic nitrate respiration.

    PubMed Central

    Carter, J P; Hsaio, Y H; Spiro, S; Richardson, D J

    1995-01-01

    Several laboratory strains of gram-negative bacteria are known to be able to respire nitrate in the presence of oxygen, although the physiological advantage gained from this process is not entirely clear. The contribution that aerobic nitrate respiration makes to the environmental nitrogen cycle has not been studied. As a first step in addressing this question, a strategy which allows for the isolation of organisms capable of reducing nitrate to nitrite following aerobic growth has been developed. Twenty-nine such strains have been isolated from three soils and a freshwater sediment and shown to comprise members of three genera (Pseudomonas, Aeromonas, and Moraxella). All of these strains expressed a nitrate reductase with an active site located in the periplasmic compartment. Twenty-two of the strains showed significant rates of nitrate respiration in the presence of oxygen when assayed with physiological electron donors. Also isolated was one member of the gram-positive genus Arthrobacter, which was likewise able to respire nitrate in the presence of oxygen but appeared to express a different type of nitrate reductase. In the four environments studied, culturable bacteria capable of aerobic nitrate respiration were isolated in significant numbers (10(4) to 10(7) per g of soil or sediment) and in three cases were as abundant as, or more abundant than, culturable bacteria capable of denitrification. Thus, it seems likely that the corespiration of nitrate and oxygen may indeed make a significant contribution to the flux of nitrate to nitrite in the environment. PMID:7487017

  20. Effects of Eichhornia crassipes and Ceratophyllum demersum on Soil and Water Environments and Nutrient Removal in Wetland Microcosms.

    PubMed

    Sung, Kijune; Lee, Geun-Joo; Munster, Clyde

    2015-01-01

    Wetland plants are important components that influence the biogeochemistry of wetland ecosystems. Therefore, remediation performance in wetlands can differ depending on the growth forms of plants. In this study, the effects of Eichhornia crassipes (floating plant) and Ceratophyllum demersum (submerged plant) on the wetland soil and water environments were investigated using a microcosm study with simulated hydrology of retention-type wetlands between rainfall events. The C. demersum microcosm (SP) showed the fastest recovery with a diel fluctuation pattern of dissolved oxygen, pH, and oxidation-reduction potential (ORP) from the impacts of nutrient inflow. Moreover, SP exhibited the lowest decrease in sediment ORP, the highest dehydrogenase activity, and more organic forms of nitrogen and phosphorus. E. crassipes microcosms exhibited the lowest water temperature, and efficiently controlled algae. In the presence of plants, the total nitrogen and phosphorus concentrations in water rapidly decreased, and the composition of organic and inorganic nutrient forms was altered along with a decrease in concentration. The results indicate that wetland plants help retain nutrients in the system, but the effects varied based on the wetland plant growth forms. PMID:25581097

  1. The influence of nickel on the bioremediation of multi-component contaminated tropical soil: microcosm and batch bioreactor studies.

    PubMed

    Taketani, Natália Franco; Taketani, Rodrigo Gouvêa; Leite, Selma Gomes Ferreira; Rizzo, Andrea Camardella de Lima; Tsai, Siu Mui; da Cunha, Cláudia Duarte

    2015-07-01

    Large petrochemical discharges are responsible for organic and inorganic pollutants in the environment. The purpose of this study was to evaluate the influence of nickel, one of the most abundant inorganic element in crude oil and the main component of hydrogen catalysts for oil refining, on the microbial community structure in artificially petroleum-contaminated microcosms and in solid phase bioreactor studies. In the presence of metals, the oil biodegradation in microcosms was significantly delayed during the first 7 days of operation. Also, increasing amounts of moisture generated a positive influence on the biodegradation processes. The oil concentration, exhibiting the most negative influence at the end of the treatment period. Molecular fingerprinting analyses (denaturing gradient gel electrophoresis--DGGE) indicated that the inclusion of nickel into the contaminated soil promoted direct changes to the microbial community structure. By the end of the experiments, the results of the total petroleum hydrocarbons removal in the bioreactor and the microcosm were similar, but reductions in the treatment times were observed with the bioreactor experiments. An analysis of the microbial community structure by DGGE using various markers showed distinct behaviors between two treatments containing high nickel concentrations. The main conclusion of this study was that Nickel promotes a significant delay in oil biodegradation, despite having only a minor effect over the microbial community. PMID:25940327

  2. Biotransformations of Aroclor 1242 in Hudson River test tube microcosms

    SciTech Connect

    Fish, K.M.; Principe, J.M.

    1994-12-01

    Polychlorinated biphenyls (PCBs) are relatively unreactive and hydrophobic, are widely used commercially, and have accumulated in soils, sediments, and biota. The researchers partially simulated environmental conditions in the laboratory to examine the fate of Aroclor 1242 in the Upper Hudson River. The test tube microcosms developed both aerobic and anaerobic compartments. This paper reports on the patterns and rates of anaerobic and aerobic PCB transformations for a single set of conditions in static, unamended microosms to model the environmental fate of Aroclor 1242 in river sediments. 23 refs., 5 figs.

  3. 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

  4. Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil.

    PubMed

    Liu, Chen; Liu, Jinxia

    2016-05-01

    Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) has recently been confirmed to occur in activated sludge and soil. However, there lacks quantitative information about the half-lives of the PAPs and their significance as the precursors to PFCAs. In the present study, the biotransformation of 6:2 and 8:2 diPAP in aerobic soil was investigated in semi-dynamics reactors using improved sample preparation methods. To develop an efficient extraction method for PAPs, six different extraction solvents were compared, and the phenomenon of solvent-enhanced hydrolysis was investigated. It was found that adding acetic acid could enhance the recoveries of the diPAPs and inhibit undesirable hydrolysis during solvent extraction of soil. However 6:2 and 8:2 monoPAPs, which are the first breakdown products from diPAPs, were found to be unstable in the six solvents tested and quickly hydrolyzed to form fluorotelomer alcohols. Therefore reliable measurement of the monoPAPs from a live soil was not achievable. The apparent DT50 values of 6:2 diPAP and 8:2 diPAP biotransformation were estimated to be 12 and > 1000 days, respectively, using a double first-order in parallel model. At the end of incubation of day 112, the major degradation products of 6:2 diPAP were 5:3 fluorotelomer carboxylic acid (5:3 acid, 9.3% by mole), perfluoropentanoic acid (PFPeA, 6.4%) and perfluorohexanoic acid (PFHxA, 6.0%). The primary product of 8:2 diPAP was perfluorooctanoic acid (PFOA, 2.1%). The approximately linear relationship between the half-lives of eleven polyfluoroalkyl and perfluoroalkyl substances (PFASs, including 6:2 and 8:2 diPAPs) that biotransform in aerobic soils and their molecular weights suggested that the molecular weight is a good indicator of the general stability of low-molecular-weight PFAS-based compounds in aerobic soils. PMID:26849529

  5. Small-scale soil water repellency in pine rizhosphere associated with ectomycorrhiza is affected by nutrient patchiness: a soil microcosms study

    NASA Astrophysics Data System (ADS)

    Lozano, Elena; Hallett, Paul; Johnson, David; Moore, Lucy; Mataix-Solera, Jorge; Jiménez-Pinilla, Patricia; Arcenegui, Victoria

    2014-05-01

    Soil water repellency (SWR) or hydrophobicity has been commonly related to organic compounds released from the roots or decomposition of different plant species (Doerr et al., 2000). In addition, fungi and microorganisms that are associated with specific plants, could also influence SWR through the production of exudates or cellular material that form hydrophobic coatings on soil surfaces (Feeney et al., 2004; Hallett and Young, 1999) or act as surfactants. Nutrient availability, microbial biomass, organic matter and specific exudates have all been associated with the development of SWR. In terms of plant productivity, these impacts can be significant as their interaction with pore structure changes at the root-soil interface regulates both water transport and storage (Sperry et al., 1998). In boreal forests, basidiomycetous fungi are known to have a large impact on the development of SWR. These fungi are important degraders of organic material and symbionts forming ectomycorrhizal fungi (EF) associations with trees. Although many researchers have suggested a strong positive impact of EF on the ability of plants to capture water from soils, their impact on SWR at the root-soil interface and spatially within soil with a patchy nutrient distribution has not yet been investigated. This study used microcosms with mycelia systems of the EF extending from Pinus sylvestris host plants. Each microcosm was incubated during 15 days and contained plastic cup with 33P under the roots. The transfer of P from the mycelium to the host plant was monitored using a radioactive tracers and a non-destructive electronic autoradiography system in another study (data not published). SWR was measured using different approaches; as repellency index, R using a microinfiltrometer with a contact radius of 0.1 mm (modified from Hallet et al., 2002) and with the water drop penetration time test (WDPT). Sorptivity and SWR were measured between 40-50 points/microcosms. Results obtained with both

  6. Transfer of elements relevant to nuclear fuel cycle from soil to boreal plants and animals in experimental meso- and microcosms.

    PubMed

    Tuovinen, Tiina S; Kasurinen, Anne; Häikiö, Elina; Tervahauta, Arja; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka

    2016-01-01

    Uranium (U), cobalt (Co), molybdenum (Mo), nickel (Ni), lead (Pb), thorium (Th) and zinc (Zn) occur naturally in soil but their radioactive isotopes can also be released into the environment during the nuclear fuel cycle. The transfer of these elements was studied in three different trophic levels in experimental mesocosms containing downy birch (Betula pubescens), narrow buckler fern (Dryopteris carthusiana) and Scandinavian small-reed (Calamagrostis purpurea ssp. Phragmitoides) as producers, snails (Arianta arbostorum) as herbivores, and earthworms (Lumbricus terrestris) as decomposers. To determine more precisely whether the element uptake of snails is mainly via their food (birch leaves) or both via soil and food, a separate microcosm experiment was also performed. The element uptake of snails did not generally depend on the presence of soil, indicating that the main uptake route was food, except for U, where soil contact was important for uptake when soil U concentration was high. Transfer of elements from soil to plants was not linear, i.e. it was not correctly described by constant concentration ratios (CR) commonly applied in radioecological modeling. Similar nonlinear transfer was found for the invertebrate animals included in this study: elements other than U were taken up more efficiently when element concentration in soil or food was low. PMID:26363398

  7. Assessment of metal toxicity and bioavailability in metallophyte leaf litters and metalliferous soils using Eisenia fetida in a microcosm study.

    PubMed

    Nirola, Ramkrishna; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Aryal, Rupak; Correll, Ray; Naidu, Ravi

    2016-07-01

    The leaf litters of tree species, Acacia pycnantha (Ap) and Eucalyptus camaldulensis (Ec), predominantly growing at an abandoned copper (Cu) mine and mine soils including controls, were assessed for determining the metal toxicity and bioavailability using earthworm species Eisenia fetida, in a microcosm. Significant reduction in body weight as well as mortality were observed when the worms were introduced into mine soil or its combination with mine Ap litter. Virtually, there were no juveniles when the worms were fed on substratum that contained mine soil or mine leaf litter. The extent of bioaccumulation was dependent on water-soluble fraction of a metal in soil. The accumulation of cadmium, lead and copper in worm tissue was significantly more in treatments that received mine soil with or without mine leaf litter. However, the tissue concentration of zinc did not differ much in earthworms irrespective of its exposure to control or contaminated samples. Mine leaf litter from Ec, a known Cu hyperaccumulator, was more hospitable to earthworm survival and juvenile than that of Ap litter. Validation of the data on bioaccumulation of metals indicated that the mine leaf litter significantly contributed to metal bioavailability. However, it was primarily the metal concentration in mine soil that was responsible for earthworm toxicity and bioavailability. Our data also indicate that detrivores like earthworm is greatly responsible for heavy metal transfer from mines into the ecosystem. PMID:27057994

  8. Impact of Bt corn on rhizospheric and soil eubacterial communities and on beneficial mycorrhizal symbiosis in experimental microcosms.

    PubMed

    Castaldini, M; Turrini, A; Sbrana, C; Benedetti, A; Marchionni, M; Mocali, S; Fabiani, A; Landi, S; Santomassimo, F; Pietrangeli, B; Nuti, M P; Miclaus, N; Giovannetti, M

    2005-11-01

    A polyphasic approach has been developed to gain knowledge of suitable key indicators for the evaluation of environmental impact of genetically modified Bt 11 and Bt 176 corn lines on soil ecosystems. We assessed the effects of Bt corn (which constitutively expresses the insecticidal toxin from Bacillus thuringiensis, encoded by the truncated Cry1Ab gene) and non-Bt corn plants and their residues on rhizospheric and bulk soil eubacterial communities by means of denaturing gradient gel electrophoresis analyses of 16S rRNA genes, on the nontarget mycorrhizal symbiont Glomus mosseae, and on soil respiration. Microcosm experiments showed differences in rhizospheric eubacterial communities associated with the three corn lines and a significantly lower level of mycorrhizal colonization in Bt 176 corn roots. In greenhouse experiments, differences between Bt and non-Bt corn plants were detected in rhizospheric eubacterial communities (both total and active), in culturable rhizospheric heterotrophic bacteria, and in mycorrhizal colonization. Plant residues of transgenic plants, plowed under at harvest and kept mixed with soil for up to 4 months, affected soil respiration, bacterial communities, and mycorrhizal establishment by indigenous endophytes. The multimodal approach utilized in our work may be applied in long-term field studies aimed at monitoring the real hazard of genetically modified crops and their residues on nontarget soil microbial communities. PMID:16269702

  9. Release of trace metals, sulfate and complexed cyanide from soils contaminated with gas-purifier wastes: a microcosm study.

    PubMed

    Rennert, T; Mansfeldt, T

    2006-01-01

    Deposited gas-purifier wastes are commonly contaminated with trace metals, sulfate and cyanide (CN) compounds. We investigated their release from three soils contaminated with gas-purifier wastes into solution in microcosm experiments under varying redox conditions (E(H) 170-620 mV). The soils differed in pH (2.2; 4.9; 7.4) and featured low amounts of trace metals, but large amounts of total S and total CN. The pH governed trace metal release in the case of the acidic soil and CN release in the case of the slightly alkaline soil. The redox potential controlled trace metal and CN release in the case of the moderately acidic soil. Sources of dissolved SO(4)(2-) were dissolution of gypsum, desorption from Fe oxides and probably oxidation of elemental S. The geochemical behaviors of trace metals (soluble under acidic and reducing conditions) and CN (soluble under alkaline and oxidizing conditions) were diametrically opposed. PMID:16019115

  10. Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

    PubMed

    Ranjard, Lionel; Echairi, Abdelwahad; Nowak, Virginie; Lejon, David P H; Nouaïm, Rachida; Chaussod, Rémi

    2006-11-01

    The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations. PMID:17064271

  11. Aerobic degradation and photolysis of tylosin in water and soil.

    PubMed

    Hu, Dingfei; Coats, Joel R

    2007-05-01

    Veterinary antibiotics enter the environment through the application of organic fertilizers to cropland. In this study, the aerobic degradation of tylosin, a widely used antibiotic in the production of livestock and poultry, was conducted in water and in soil in an effort to further investigate its environmental fate. Tylosin is a macrolide antibiotic, which consists of four factors (A, B, C, D). Water and soil were sampled at selected times and analyzed for tylosin and its degradation products by high-performance liquid chromatography (HPLC), with product identification confirmed by HPLC-mass spectrometry. Tylosin A is degraded with a half-life of 200 d in the light in water, and the total loss of tylosin A in the dark is 6% of the initial spiked amount during the experimental period. Tylosin C and D are relatively stable except in ultrapure water in the light. Slight increases of tylosin B after two months and formation of two photoreaction isomers of tylosin A were observed under exposure to light. However, tylosin probably would degrade faster if the experimental containers did not prevent ultraviolet transmission. In soil, tylosin A has a dissipation half-life of 7 d, and tylosin D is slightly more stable, with a dissipation half-life of 8 d in unsterilized and sterilized soil. Sorption and abiotic degradation are the major factors influencing the loss of tylosin in the environment, and no biotic degradation was observed at the test concentration either in pond water or in an agronomic soil, as determined by comparing dissipation profiles in sterilized and unsterilized conditions. PMID:17521133

  12. Response of forest seedling/soil microcosms to elevated CO{sub 2} and soil temperature, water, and light: Carbon and nitrogen mineralization and allocation

    SciTech Connect

    Gillham, M.L.; Perry, D.A.

    1995-09-01

    Soils from 500-year-old old-growth Douglas-fir forests in the western Oregon Cascade Mtns. (945m and 1325m sites) were {open_quotes}incubated{close_quotes} for 32 weeks in controlled-environment chambers. Objectives were (1) to determine the interacting effects of soil temperature and atmospheric CO{sub 2} on N availability in soils, growth of Douglas-fir seedlings, and resulting C & N fluxes among trees, soils, and the atmosphere, and (2) to model these interactions with a version of Fregro linked with the GEM soil-decomposition model. The experiment was a split-plot with a factorial treatment combination containing two leves each of atmospheric CO{sub 2} (350/700 ppm), soil temperature (13.8/17.7{degrees}C), soil C & N (1325m soils had 2.3x more C and 1.25x more N than 945m soils), and vegetation (+/-seedlings). Each wholeplot (chamber) treatment (CO{sub 2} x temperature) was replicated three times. Photosynthetic photon flux density, soil temperature, and volume of added water were determined for each pot and analyzed as covariates. Responses measured include differences in soil C & N mineralization and total soil C & N in the presence/absence of seedlings, the extent to which subsequent seedling growth offsets potential {open_quote}system{close_quote} losses of C & N, and allocation of C & N to foliage and fine roots. Previously reported early results (ESA, 1994) suggest that (1) as hypothesized, soil temperatures is the main driver of changes in both N mineralization and biomass production in seedling microcosms, (2) allocation is primarily influenced by atmospheric CO{sub 2} concentration, and (3) a soil type x soil temperature x CO{sub 2} interaction influences seedling growth.

  13. Survival and impact of genetically engineered Pseudomonas putida harboring mercury resistance gene in soil microcosms.

    PubMed

    Iwasaki, K; Uchiyama, H; Yagi, O

    1994-01-01

    The survival of genetically engineered and wild-type Pseudomonas putida PpY101, that contained a recombinant plasmid pSR134 conferring mercury resistance, were monitored in andosol and sand microcosms. The survival of genetically engineered and wild-type P. putida was not significantly different in andosol. The population change of the two strains was dissimilar in andosol and sand. The survival of genetically engineered and wild-type P. putida strains was affected by the water content of andosol, and increased with the increment of the water content. The impact of the addition of genetically engineered and wild-type P. putida strains on indigenous bacteria and fungi was examined. Inoculation of both strains had no apparent effect on the density of indigenous microorganisms. PMID:7764510

  14. Identification of Unknown Carboxydovore Bacteria Dominant in Deciduous Forest Soil via Succession of Bacterial Communities, coxL Genotypes, and Carbon Monoxide Oxidation Activity in Soil Microcosms

    PubMed Central

    Lalonde, Isabelle

    2015-01-01

    Surveys of the coxL gene, encoding the large subunit of the CO dehydrogenase, are used as a standard approach in ecological studies of carboxydovore bacteria scavenging atmospheric CO. Recent soil surveys unveiled that the distribution of coxL sequences encompassing the atypical genotype coxL type I group x was correlated to the CO oxidation activity. Based on phylogenetic analysis including the available coxL reference genome sequences, this unusual genotype was assigned to an unknown member of the Deltaproteobacteria, with the coxL sequence from Haliangium ochraceum being the sole and closest reference sequence. Here we seek to challenge the proposed taxonomic assignation of the coxL group x genotype through the monitoring of CO consumption activity and microbial community successions during the colonization of sterile soil microcosms inoculated with indigenous microorganisms. In our study, we established that the estimated population density of Deltaproteobacteria was too small to account for the abundance of the coxL group x genotype detected in soil. Furthermore, we computed a correlation network to relate 16S rRNA gene profiles with the succession of coxL genotypes and CO uptake activity in soil. We found that most of the coxL genotypes for which the colonization profile displayed covariance with CO uptake activity were related to potential carboxydovore bacteria belonging to Actinobacteria and Alphaproteobacteria. Our analysis did not provide any evidence that coxL group x genotypes belonged to Deltaproteobacteria. Considering the colonization profile of CO-oxidizing bacteria and the theoretical energy yield of measured CO oxidation rates in soil microcosms, we propose that unknown carboxydovore bacteria harboring the atypical coxL group x genotype are mixotrophic K-strategists. PMID:26682854

  15. Identification of Unknown Carboxydovore Bacteria Dominant in Deciduous Forest Soil via Succession of Bacterial Communities, coxL Genotypes, and Carbon Monoxide Oxidation Activity in Soil Microcosms.

    PubMed

    Lalonde, Isabelle; Constant, Philippe

    2016-02-01

    Surveys of the coxL gene, encoding the large subunit of the CO dehydrogenase, are used as a standard approach in ecological studies of carboxydovore bacteria scavenging atmospheric CO. Recent soil surveys unveiled that the distribution of coxL sequences encompassing the atypical genotype coxL type I group x was correlated to the CO oxidation activity. Based on phylogenetic analysis including the available coxL reference genome sequences, this unusual genotype was assigned to an unknown member of the Deltaproteobacteria, with the coxL sequence from Haliangium ochraceum being the sole and closest reference sequence. Here we seek to challenge the proposed taxonomic assignation of the coxL group x genotype through the monitoring of CO consumption activity and microbial community successions during the colonization of sterile soil microcosms inoculated with indigenous microorganisms. In our study, we established that the estimated population density of Deltaproteobacteria was too small to account for the abundance of the coxL group x genotype detected in soil. Furthermore, we computed a correlation network to relate 16S rRNA gene profiles with the succession of coxL genotypes and CO uptake activity in soil. We found that most of the coxL genotypes for which the colonization profile displayed covariance with CO uptake activity were related to potential carboxydovore bacteria belonging to Actinobacteria and Alphaproteobacteria. Our analysis did not provide any evidence that coxL group x genotypes belonged to Deltaproteobacteria. Considering the colonization profile of CO-oxidizing bacteria and the theoretical energy yield of measured CO oxidation rates in soil microcosms, we propose that unknown carboxydovore bacteria harboring the atypical coxL group x genotype are mixotrophic K-strategists. PMID:26682854

  16. Direct Link between Toluene Degradation in Contaminated-Site Microcosms and a Polaromonas Strain ▿

    PubMed Central

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

    2010-01-01

    Stable isotope probing (SIP) was used to identify the aerobic toluene-degrading microorganism in soil microcosms. Several approaches (terminal restriction fragment length polymorphism, 16S rRNA gene sequencing, and quantitative PCR) provided evidence that the microorganism responsible was a member of the genus Polaromonas and could grow on toluene. This microorganism also transformed benzene, but not m-xylene or cis-dichloroethene. PMID:20008173

  17. Evolution of organic matter fractions after application of co-compost of sewage sludge with pruning waste to four Mediterranean agricultural soils. A soil microcosm experiment.

    PubMed

    Pérez-Lomas, A L; Delgado, G; Párraga, J; Delgado, R; Almendros, G; Aranda, V

    2010-10-01

    The effect of co-compost application from sewage sludge and pruning waste, on quality and quantity of soil organic carbon (SOC) in four Mediterranean agricultural soils (South Spain), was studied in soil microcosm conditions. Control soil samples (no co-compost addition) and soils treated with co-composts to a rate equivalent of 140 Mg ha(-1) were incubated for 90 days at two temperatures: 5 and 35 degrees C. The significances of incubation temperature and the addition of co-compost, on the evolution of the different fractions of SOC, were studied using a 2(3) factorial design. The co-compost amendment increased the amounts of humic fractions: humic acids (HA) (1.9 times), fulvic acids (FA) (3.3 times), humin (1.5 times), as well as the free organic matter (1.4 times) and free lipids (21.8 times). Incubation of the soils enhanced its biological activity mainly in the amended soils and at 35 degrees C, leading to progressive SOC mineralization and humification, concomitant to the preferential accumulation of HA. The incubation results show large differences depending on temperature and soil types. This fact allows us to select suitable organic amendment for the soil when a rapid increase in nutrients through mineralization is preferred, or in cases intending the stabilization and preservation of the SOC through a process of humification. In soils with HA of more than 5 E(4)/E(6) ratio, the incubation temperature increased rates of mineralization and humification, whereas lower temperatures limited the extent of both processes. In these soils the addition of co-compost in spring or summer is the most recommendable. In soils with HA of lower E(4)/E(6) ratio (<5), the higher temperature favoured mineralization but not humification, whereas the low temperature maintained the SOC levels and even increased the HA/FA ratio. In these soils the moment of addition of organic amendment should be decided depending on the effect intended. On the other hand, the lower the SOC

  18. Physicochemical Factors Affecting the Growth of Burkholderia pseudomallei in Soil Microcosm

    PubMed Central

    Wang-ngarm, Supunnipa; Chareonsudjai, Sorujsiri; Chareonsudjai, Pisit

    2014-01-01

    Burkholderia pseudomallei causes melioidosis, the third most common cause of death from infectious diseases in northeast Thailand. Four physicochemical factors were set so that their values covered the range of the northeast, which is an endemic area. The soil pH was set at pH 4–10, soil salinity was 0.0–5.0% NaCl, total iron was 50–150 mg/kg soil, and carbon to nitrogen ratio (C/N) was 10:1 to 40:1. The experiments were carried out at 37°C, and soil moisture was maintained for 7 days. The number of viable bacterial cells was counted daily. Soil pH, salinity, Fe, and C/N ratio affected the bacterial growth. The bacterial colony was significantly (P < 0.05) reduced at soil pH > 8, soil salinity > 1% NaCl, and C/N ratio > 40:1. However, the growth of B. pseudomallei was enhanced by increasing the concentrations of iron significantly (P < 0.05). We propose using these findings to control B. pseudomallei in situ. PMID:24445210

  19. Red spruce germination and growth in soil-mediated regeneration microcosms under acid precipitation

    SciTech Connect

    Ho, M.

    1992-01-01

    In the past three decades, atmospheric pollution has caused substantial problems for the environment as well as for many biological processes. The objective of this study focuses on red spruce (Picea ruben Sarg.) regeneration potential and chemical change within the soil-water-plant continuum following simulated acid rain treatments. Inceptisols from three forests at 1735, 1920, and 2015 m at Mt. Mitchell, North Carolina had lower pH, bulk density, and higher organic matter, and base cations as altitude increased. Red spruce seeds were collected from two nearby standing trees at the 1735 m site. A strip-split-split plot experiment was constructed using soils from the two lower elevations, which support natural red spruce stands. Besides a control (pH 5.6, NO[sub 3]:SO[sub 4] ratio 0.10), eight treatments corresponding to two pHs (3.5 and 4.2) with four NO[sub 3]:SO[sub 4] ratios (0.20, 0.33, 0.40, and 0.67) each were used. Seedling emergence and growth, chemistry of soil. Soil leachate, and plant tissue were analyzed to test soil differences and treatment effects of acidity, nitrate, and sulfate. Temporal patterns of germination respond more to soil than to rain chemistry, but significant interactions were found. Besides higher survival, faster germinating seedlings in the 1735 m soil also produced more complex root system and more biomass. Lower root-to-shoot ratios at more acidic treatments suggest a negative effect of acidity on root growth. Canonical discriminant analysis revealed that factors controlling overall soil chemistry were dominated by soil origin, then by rain pH.

  20. Impact of herbicides on the abundance and structure of indigenous beta-subgroup ammonia-oxidizer communities in soil microcosms.

    PubMed

    Chang, Y J; Hussain, A K; Stephen, J R; Mullen, M D; White, D C; Peacock, A

    2001-11-01

    In this study, mixtures of five herbicide-formulated products (atrazine, dicamba, fluometuron, metolachlor, and sulfentrazone) were applied to soil microcosm columns in increasing concentrations. The toxic impact of herbicides on the indigenous beta-subclass Proteobacteria autotrophic ammonia-oxidizer (beta-AAO) community was assessed. The beta-AAO population abundances were estimated by competitive polymerase chain reaction (PCR) targeting the gene amoA, encoding the alpha-subunit of ammonia monooxygenase. Community structure was examined by PCR and denaturing gradient gel electrophoresis targeting 16S rDNA with band excision and sequence analysis, and by analysis of amoA gene fragment clone libraries. The 16S rDNA analyses showed that a single ribotype of Nitrosospira cluster 3 was the dominant beta-AAO in all treatments. At a finer scale, amoA clone library analysis suggested a shift in community structure corresponding to the 100-ppm application. Competitive PCR indicated significant differences between treatments. The control exhibited relatively stable population abundance over the time period examined. The 10-ppm treatment induced a population increase, but a significant decrease was induced by the 100-ppm application. At 1,000 ppm, the ammonia-oxidizer population dropped below the method detection limit by the first sampling point. An impact on ammonia oxidizers resulting from the application of herbicides was observed, both in abundance and community structure. PMID:11699770

  1. Detection and quantification of a mycorrhization helper bacterium and a mycorrhizal fungus in plant-soil microcosms at different levels of complexity

    PubMed Central

    2013-01-01

    Background Host plant roots, mycorrhizal mycelium and microbes are important and potentially interacting factors shaping the performance of mycorrhization helper bacteria (MHB). We investigated the impact of a soil microbial community on the interaction between the extraradical mycelium of the ectomycorrhizal fungus Piloderma croceum and the MHB Streptomyces sp. AcH 505 in both the presence and the absence of pedunculate oak microcuttings. Results Specific primers were designed to target the internal transcribed spacer of the rDNA and an intergenic region between two protein encoding genes of P. croceum and the intergenic region between the gyrA and gyrB genes of AcH 505. These primers were used to perform real-time PCR with DNA extracted from soil samples. With a sensitivity of 10 genome copies and a linear range of 6 orders of magnitude, these real-time PCR assays enabled the quantification of purified DNA from P. croceum and AcH 505, respectively. In soil microcosms, the fungal PCR signal was not affected by AcH 505 in the absence of the host plant. However, the fungal signal became weaker in the presence of the plant. This decrease was only observed in microbial filtrate amended microcosms. In contrast, the PCR signal of AcH 505 increased in the presence of P. croceum. The increase was not significant in sterile microcosms that contained plant roots. Conclusions Real-time quantitative PCR assays provide a method for directly detecting and quantifying MHB and mycorrhizal fungi in plant microcosms. Our study indicates that the presence of microorganisms and plant roots can both affect the nature of MHB-fungus interactions, and that mycorrhizal fungi may enhance MHB growth. PMID:24025151

  2. 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

  3. Microbial secondary succession in soil microcosms of a desert oasis in the Cuatro Cienegas Basin, Mexico.

    PubMed

    López-Lozano, Nguyen E; Heidelberg, Karla B; Nelson, William C; García-Oliva, Felipe; Eguiarte, Luis E; Souza, Valeria

    2013-01-01

    Ecological succession is one of the most important concepts in ecology. However for microbial community succession, there is a lack of a solid theoretical framework regarding succession in microorganisms. This is in part due to microbial community complexity and plasticity but also because little is known about temporal patterns of microbial community shifts in different kinds of ecosystems, including arid soils. The Cuatro Cienegas Basin (CCB) in Coahuila, Mexico, is an arid zone with high diversity and endemisms that has recently been threatened by aquifer overexploitation. The gypsum-based soil system of the CCB is one of the most oligotrophic places in the world. We undertook a comparative 16S rRNA 454 pyrosequencing study to evaluate microbial community succession and recovery over a year after disturbance at two sites. Results were related to concurrent measurements of humidity, organic matter and total C and N content. While each site differed in both biogeochemistry and biodiversity, both present similar pattern of change at the beginning of the succession that diverged in later stages. After one year, experimentally disturbed soil was not similar to established and undisturbed adjacent soil communities indicating recovery and succession in disturbed soils is a long process. PMID:23638384

  4. Microbial secondary succession in soil microcosms of a desert oasis in the Cuatro Cienegas Basin, Mexico

    PubMed Central

    López-Lozano, Nguyen E.; Heidelberg, Karla B.; Nelson, William C.; García-Oliva, Felipe; Eguiarte, Luis E.

    2013-01-01

    Ecological succession is one of the most important concepts in ecology. However for microbial community succession, there is a lack of a solid theoretical framework regarding succession in microorganisms. This is in part due to microbial community complexity and plasticity but also because little is known about temporal patterns of microbial community shifts in different kinds of ecosystems, including arid soils. The Cuatro Cienegas Basin (CCB) in Coahuila, Mexico, is an arid zone with high diversity and endemisms that has recently been threatened by aquifer overexploitation. The gypsum-based soil system of the CCB is one of the most oligotrophic places in the world. We undertook a comparative 16S rRNA 454 pyrosequencing study to evaluate microbial community succession and recovery over a year after disturbance at two sites. Results were related to concurrent measurements of humidity, organic matter and total C and N content. While each site differed in both biogeochemistry and biodiversity, both present similar pattern of change at the beginning of the succession that diverged in later stages. After one year, experimentally disturbed soil was not similar to established and undisturbed adjacent soil communities indicating recovery and succession in disturbed soils is a long process. PMID:23638384

  5. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    SciTech Connect

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  6. Monitoring Arthrobacter protophormiae RKJ100 in a 'tag and chase' method during p-nitrophenol bio-remediation in soil microcosms.

    PubMed

    Pandey, Gunjan; Pandey, Janmejay; Jain, Rakesh K

    2006-05-01

    Monitoring of micro-organisms released deliberately into the environment is essential to assess their movement during the bio-remediation process. During the last few years, DNA-based genetic methods have emerged as the preferred method for such monitoring; however, their use is restricted in cases where organisms used for bio-remediation are not well characterized or where the public domain databases do not provide sufficient information regarding their sequence. For monitoring of such micro-organisms, alternate approaches have to be undertaken. In this study, we have specifically monitored a p-nitrophenol (PNP)-degrading organism, Arthrobacter protophormiae RKJ100, using molecular methods during PNP degradation in soil microcosm. Cells were tagged with a transposon-based foreign DNA sequence prior to their introduction into PNP-contaminated microcosms. Later, this artificially introduced DNA sequence was PCR-amplified to distinguish the bio-augmented organism from the indigenous microflora during PNP bio-remediation. PMID:16205921

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

    EPA Science Inventory

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

  8. Interactions of Bacterial and Amoebal Populations in Soil Microcosms with Fluctuating Moisture Content

    PubMed Central

    Bryant, R. J.; Woods, L. E.; Coleman, D. C.; Fairbanks, B. C.; McClellan, J. F.; Cole, C. V.

    1982-01-01

    Sterilized soil samples (20 g of soil per 50-ml flask), amended with 600 μg of glucose-carbon and 60 μg of NH4-N · g of dry soil−1, were inoculated with bacteria (Pseudomonas paucimobilis) alone or with bacteria and amoebae (Acanthamoeba polyphaga). We used wet-dry treatments, which involved air drying the samples to a moisture content of approximately 2% and remoistening the samples three times during the 83-day experiment. Control treatments were kept moist. In the absence of amoebae, bacterial populations were reduced by the first drying to about 60% of the moist control populations, but the third drying had no such effect. With amoebae present, bacterial numbers were not significantly affected by the dryings. Amoebal grazing reduced bacterial populations to 20 to 25% of the ungrazed bacterial populations in both moisture treatments. Encystment was an efficient survival mechanism for amoebae subjected to wet-dry cycles. The amoebal population was entirely encysted in dry soil, but the total number of amoebae was not affected by the three dryings. Growth efficiencies for amoebae feeding on bacteria were 0.33 and 0.39 for wet-dry and constantly moist treatments, respectively, results that compared well with those previously reported for Acanthamoeba spp. PMID:16345984

  9. Sequential anaerobic-aerobic degradation of indigenous PCBs in a contaminated soil matrix

    SciTech Connect

    Klasson, K.T.; Reeves, M.E.; Evans, B.S.; Dudley, C.A.

    1994-12-31

    Many industrial locations, including the US Department of Energy`s, have identified needs for treatment of polychlorinated biphenyl (PCB) wastes and remediation of PCB-contaminated sites. Biodegradation of PCBs is a potentially effective technology for the treatment of PCB-contaminated soils and sludges; however, a practicable remediation technology has not yet been demonstrated. A biological treatment technology is likely to consist of an anaerobic fermentation step in which PCB dechlorination takes place producing PCBs with fewer chlorines. These products are then more susceptible to aerobic mineralization. In laboratory experiments, soil slurry bioreactors inoculated with microorganisms extracted from PCB-contaminated sediments from the Hudson River and Woods Pond have been used to obtain anaerobic dechlorination of PCBs in soil slurry reactors. The anaerobic dechlorination was followed by qualitative estimation of the effect of aerobic fermentation of the dechlorination products based on literature data. The sequential anaerobic-(simulated) aerobic treatment constituted an improvement compared anaerobic treatment alone.

  10. Genetically engineered Pseudomonas putida X3 strain and its potential ability to bioremediate soil microcosms contaminated with methyl parathion and cadmium.

    PubMed

    Zhang, Rong; Xu, Xingjian; Chen, Wenli; Huang, Qiaoyun

    2016-02-01

    A multifunctional Pseudomonas putida X3 strain was successfully engineered by introducing methyl parathion (MP)-degrading gene and enhanced green fluorescent protein (EGFP) gene in P. putida X4 (CCTCC: 209319). In liquid cultures, the engineered X3 strain utilized MP as sole carbon source for growth and degraded 100 mg L(-1) of MP within 24 h; however, this strain did not further metabolize p-nitrophenol (PNP), an intermediate metabolite of MP. No discrepancy in minimum inhibitory concentrations (MICs) to cadmium (Cd), copper (Cu), zinc (Zn), and cobalt (Co) was observed between the engineered X3 strain and its host strain. The inoculated X3 strain accelerated MP degradation in different polluted soil microcosms with 100 mg MP kg(-1) dry soil and/or 5 mg Cd kg(-1) dry soil; MP was completely eliminated within 40 h. However, the presence of Cd in the early stage of remediation slightly delayed MP degradation. The application of X3 strain in Cd-contaminated soil strongly affected the distribution of Cd fractions and immobilized Cd by reducing bioavailable Cd concentrations with lower soluble/exchangeable Cd and organic-bound Cd. The inoculated X3 strain also colonized and proliferated in various contaminated microcosms. Our results suggested that the engineered X3 strain is a potential bioremediation agent showing competitive advantage in complex contaminated environments. PMID:26521245

  11. 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. PMID:21179963

  12. 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.

  13. An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia

    PubMed Central

    Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

    2014-01-01

    Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

  14. An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.

    PubMed

    Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

    2014-08-01

    Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

  15. 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.

  16. Atrazine remediation in wetland microcosms.

    PubMed

    Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

    2001-05-01

    Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column. PMID:11337869

  17. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems. PMID:20382410

  18. The University as Microcosm

    ERIC Educational Resources Information Center

    Kaldis, Byron

    2009-01-01

    This paper puts forward the model of "microcosm-macrocosm" isomorphism encapsulated in certain philosophical views on the form of university education. The human being as a "microcosm" should reflect internally the external "macrocosm". Higher Education is a socially instituted attempt to guide human beings into forming themselves as microcosms of…

  19. Nitrate Reduction in a Groundwater Microcosm Determined by 15N Gas Chromatography-Mass Spectrometry

    PubMed Central

    Bengtsson, Göran; Annadotter, Heléne

    1989-01-01

    Aerobic and anaerobic groundwater continuous-flow microcosms were designed to study nitrate reduction by the indigenous bacteria in intact saturated soil cores from a sandy aquifer with a concentration of 3.8 mg of NO3−-N liter−1. Traces of 15NO3− were added to filter-sterilized groundwater by using a Darcy flux of 4 cm day−1. Both assimilatory and dissimilatory reduction rates were estimated from analyses of 15N2, 15N2O, 15NH4+, and 15N-labeled protein amino acids by capillary gas chromatography-mass spectrometry. N2 and N2O were separated on a megabore fused-silica column and quantified by electron impact-selected ion monitoring. NO3− and NH4+ were analyzed as pentafluorobenzoyl amides by multiple-ion monitoring and protein amino acids as their N-heptafluorobutyryl isobutyl ester derivatives by negative ion-chemical ionization. The numbers of bacteria and their [methyl-3H]thymidine incorporation rates were simultaneously measured. Nitrate was completely reduced in the microcosms at a rate of about 250 ng g−1 day−1. Of this nitrate, 80 to 90% was converted by aerobic denitrification to N2, whereas only 35% was denitrified in the anaerobic microcosm, where more than 50% of NO3− was reduced to NH4+. Assimilatory reduction was recorded only in the aerobic microcosm, where N appeared in alanine in the cells. The nitrate reduction rates estimated for the aquifer material were low in comparison with rates in eutrophic lakes and coastal sediments but sufficiently high to remove nitrate from an uncontaminated aquifer of the kind examined in less than 1 month. PMID:16348048

  20. 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

  1. 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

  2. Functional and structural responses of soil N-cycling microbial communities to the herbicide mesotrione: a dose-effect microcosm approach.

    PubMed

    Crouzet, Olivier; Poly, Franck; Bonnemoy, Frédérique; Bru, David; Batisson, Isabelle; Bohatier, Jacques; Philippot, Laurent; Mallet, Clarisse

    2016-03-01

    Microbial communities driving the nitrogen cycle contribute to ecosystem services such as crop production and air, soil, and water quality. The responses to herbicide stress of ammonia-oxidizing and ammonia-denitrifying microbial communities were investigated by an analysis of changes in structure-function relationships. Their potential activities, abundances (quantitative PCR), and genetic structure (denaturing gradient gel electrophoresis) were assessed in a microcosm experiment. The application rate (1 × FR, 0.45 μg g(-1) soil) of the mesotrione herbicide did not strongly affect soil N-nutrient dynamics or microbial community structure and abundances. Doses of the commercial product Callisto® (10 × FR and 100 × FR) or pure mesotrione (100 × FR) exceeding field rates induced short-term inhibition of nitrification and a lasting stimulation of denitrification. These effects could play a part in the increase in soil ammonium content and decrease in nitrate contents observed in treated soils. These functional impacts were mainly correlated with abundance shifts of ammonia-oxidizing Bacteria (AOB) and Archaea (AOA) or denitrifying bacteria. The sustained restoration of nitrification activity, from day 42 in the 100 × FR-treated soils, was likely promoted by changes in the community size and composition of AOB, which suggests a leading role, rather than AOA, for soil nitrification restoration after herbicide stress. This ecotoxicological community approach provides a nonesuch multiparameter assessment of responses of N-cycling microbial guilds to pesticide stress. PMID:26122568

  3. Unusual isotopic composition of C-CO2 from sterilized soil microcosms: a new way to separate intracellular from extracellular respiratory metabolisms.

    NASA Astrophysics Data System (ADS)

    Kéraval, Benoit; Alvarez, Gaël; Lehours, Anne Catherine; Amblard, Christian; Fontaine, Sebastien

    2015-04-01

    The mineralization of organic C requires two main steps. First, microorganisms secrete exoenzymes in soil in order to depolymerize plant and microbial cell walls and release soluble substrates for microbial assimilation. The second step of mineralization, during which C is released as CO2, implies the absorption and utilization of solubilized substrates by microbial cells with the aim to produce energy (ATP). In cells, soluble substrates are carried out by a cascade of respiratory enzymes, along which protons and electrons are transferred from a substrate to oxygen. Given the complexity of this oxidative metabolism and the typical fragility of respiratory enzymes, it is traditionally considered that respiration (second step of C mineralization process) is strictly an intracellular metabolism process. The recurrent observations of substantial CO2 emissions in soil microcosms where microbial cells have been reduced to extremely low levels challenges this paradigm. In a recent study where some respiratory enzymes have shown to function in an extracellular context in soils, Maire et al. (2013) suggested that an extracellular oxidative metabolism (EXOMET) substantially contributes to CO2 emission from soils. This idea is supported by the recent publication of Blankinship et al., 2014 who showed the presence of active enzymes involved in the Krebs cycle on soil particles. Many controversies subsist in the scientific community due to the presence of non-proliferating but morphologically intact cells after irradiation that could substantially contribute to those soil CO2 emissions. To test whether a purely extracellular oxidative metabolism contribute to soil CO2 emissions, we combined high doses of gamma irradiations to different time of soil autoclaving. The presence of active and non-active cells in soil was checked by DNA and RNA extraction and by electronic microscopy. None active cells (RNA-containing cells) were detectable after irradiation, but some morphological

  4. Changes in Denitrifier Abundance, Denitrification Gene mRNA Levels, Nitrous Oxide Emissions, and Denitrification in Anoxic Soil Microcosms Amended with Glucose and Plant Residues▿

    PubMed Central

    Henderson, Sherri L.; Dandie, Catherine E.; Patten, Cheryl L.; Zebarth, Bernie J.; Burton, David L.; Trevors, Jack T.; Goyer, Claudia

    2010-01-01

    In agricultural cropping systems, crop residues are sources of organic carbon (C), an important factor influencing denitrification. The effects of red clover, soybean, and barley plant residues and of glucose on denitrifier abundance, denitrification gene mRNA levels, nitrous oxide (N2O) emissions, and denitrification rates were quantified in anoxic soil microcosms for 72 h. nosZ gene abundances and mRNA levels significantly increased in response to all organic carbon treatments over time. In contrast, the abundance and mRNA levels of Pseudomonas mandelii and closely related species (nirSP) increased only in glucose-amended soil: the nirSP guild abundance increased 5-fold over the 72-h incubation period (P < 0.001), while the mRNA level significantly increased more than 15-fold at 12 h (P < 0.001) and then subsequently decreased. The nosZ gene abundance was greater in plant residue-amended soil than in glucose-amended soil. Although plant residue carbon-to-nitrogen (C:N) ratios varied from 15:1 to 30:1, nosZ gene and mRNA levels were not significantly different among plant residue treatments, with an average of 3.5 × 107 gene copies and 6.9 × 107 transcripts g−1 dry soil. Cumulative N2O emissions and denitrification rates increased over 72 h in both glucose- and plant-tissue-C-treated soil. The nirSP and nosZ communities responded differently to glucose and plant residue amendments. However, the targeted denitrifier communities responded similarly to the different plant residues under the conditions tested despite changes in the quality of organic C and different C:N ratios. PMID:20154105

  5. Factors affecting microbial 2,4,6-trinitrotoluene mineralization in contaminated soil

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    1995-01-01

    The influence of selected environmental factors on microbial TNT mineralization in soils collected from a TNT-contaminated site at Weldon Spring, MO, was examined using uniformly ring-labeled [14C]TNT. Microbial TNT mineralization was significantly inhibited by the addition of cellobiose and syringate. This response suggests that the indigenous microorganisms are capable of metabolizing TNT but preferentially utilize less recalcitrant substrates when available. The observed inhibition of TNT mineralization by TNT concentrations higher than 100 ??mol/kg of soil and by dry soil conditions suggests that toxic inhibition of microbial activity at high TNT concentrations and the periodic drying of these soils have contributed to the long-term persistence of TNT at Weldon Spring. In comparison to aerobic microcosms, mineralization was inhibited in anaerobic microcosms and in microcosms with a headspace of air amended with oxygen, suggesting that a mosaic of aerobic and anaerobic conditions may optimize TNT degradation at this site.

  6. Degradation of Methyl Bromide and Methyl Chloride in Soil Microcosms: Use of Stable C Isotope Fractionation and Stable Isotope Probing to Identify Reactions and the Responsible Microorganisms

    NASA Astrophysics Data System (ADS)

    Miller, L. G.; Warner, K. L.; Baesman, S. M.; Oremland, R. S.; McDonald, I. R.; Radajewski, S.; Murrell, J. C.

    2003-12-01

    Methyl bromide (MeBr) and methyl chloride (MeCl) are important atmospheric trace gases that contribute directly to stratospheric ozone depletion. These compounds have natural and anthropogenic sources and sinks in both aquatic and terrestrial environments. Soils comprise the largest known sink for MeBr on the Earth's surface and are also a large sink for MeCl. However, the processes that influence the flux of these compounds from air to soil or soil to air are poorly understood at present. Bacteria in soil microcosm experiments oxidized both MeCl and MeBr, the former compound more rapidly than the latter. MeBr was also removed by chemical reactions while MeCl was not. Chemical degradation of MeBr accounted for more than half of its total loss. We applied new techniques to determine if different bacteria were responsible for degrading MeBr and MeCl. Stable isotope probing revealed that different populations of soil bacteria assimilated added 13C-labeled MeBr and MeCl. Soil bacterial oxidation of MeBr and MeCl was characterized by different kinetic isotope effects (KIEs). The KIE for MeBr oxidation by bacteria was 22 +/- 5 \\permil and the KIE for MeCl oxidation was 56 +/- 3 \\permil, suggesting that different bacteria were responsible for degrading each compound. The identity of the active MeBr and MeCl degrading bacteria in soil was determined by analysis of 16S rDNA sequences amplified from 13C-DNA fractions. The diverse population of active bacteria was reflected by the range of sequences found for the cmuA gene, which codes for the enzyme that catalyzes the initial step in the oxidation of MeBr and MeCl. The diversity and number of different bacteria actively degrading MeBr and MeCl in the soil and the number of bacteria identified that contain the enzyme capable of degrading methyl halides were in contrast to the limited number of methyl halide degrading bacteria that have been isolated thus far from soil and aquatic environments; thus suggesting that the

  7. Dynamics of indigenous bacterial communities associated with crude oil degradation in soil microcosms during nutrient-enhanced bioremediation.

    PubMed

    Chikere, Chioma B; Surridge, Karen; Okpokwasili, Gideon C; Cloete, Thomas E

    2012-03-01

    Bacterial population dynamics were examined during bioremediation of an African soil contaminated with Arabian light crude oil and nutrient enrichment (biostimulation). Polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) were used to generate bacterial community fingerprints of the different treatments employing the 16S ribosomal ribonucleic acid (rRNA) gene as molecular marker. The DGGE patterns of the nutrient-amended soils indicated the presence of distinguishable bands corresponding to the oil-contaminated-nutrient-enriched soils, which were not present in the oil-contaminated and pristine control soils. Further characterization of the dominant DGGE bands after excision, reamplification and sequencing revealed that Corynebacterium spp., Dietzia spp., Rhodococcus erythropolis sp., Nocardioides sp., Low G+C (guanine plus cytosine) Gram positive bacterial clones and several uncultured bacterial clones were the dominant bacterial groups after biostimulation. Prominent Corynebacterium sp. IC10 sequence was detected across all nutrient-amended soils but not in oil-contaminated control soil. Total heterotrophic and hydrocarbon utilizing bacterial counts increased significantly in the nutrient-amended soils 2 weeks post contamination whereas oil-contaminated and pristine control soils remained fairly stable throughout the experimental period. Gas chromatographic analysis of residual hydrocarbons in biostimulated soils showed marked attenuation of contaminants starting from the second to the sixth week after contamination whereas no significant reduction in hydrocarbon peaks were seen in the oil-contaminated control soil throughout the 6-week experimental period. Results obtained indicated that nutrient amendment of oil-contaminated soil selected and enriched the bacterial communities mainly of the Actinobacteria phylogenetic group capable of surviving in toxic contamination with concomitant biodegradation of the hydrocarbons. The

  8. Aerobic metabolism of diclosulam on U.S. and South American soils.

    PubMed

    Yoder, R N; Huskin, M A; Kennard, L M; Zabik, J M

    2000-09-01

    Degradation of the sulfonanilide herbicide diclosulam was studied on nine soils from three countries to determine the rates and products of aerobic metabolism. Diclosulam was applied to four agricultural soils from the United States, three from Argentina, and two from Brazil at a rate of 0.1 ppm, equivalent to approximately twice the maximum field application rate of 52 g of active ingredient/ha. U.S. and Brazilian soils were incubated in the dark at 25 degrees C at 75% 0.3 bar moisture; Argentinean soils were incubated in the dark at 20 degrees C and 45% moisture holding capacity. Samples were analyzed up to one year after treatment. Two-compartment DT(50) and DT(90) values averaged 28 +/- 12 and 190 +/- 91 days, respectively. Three soil metabolites reached levels of >10% of applied in at least one soil and were identified as the 5-hydroxy analogue of diclosulam (5-OH-diclosulam), aminosulfonyl triazolopyrimidine (ASTP), and the 8-chloro-5-hydroxy analogue of diclosulam (8-Cl-diclosulam). The terminal products of diclosulam soil metabolism were mineralization to CO(2) and bound soil residues. Apparent sorption coefficients (K(d)) were determined on a subset of samples by extraction with a 0. 01 M CaCl(2) solution followed by an acidified acetone extraction. Initial sorption coefficients were similar to those obtained in a batch equilibrium study and averaged 1.1 L/kg for the six soils tested. K(d) coefficients for the metabolites, when available, tended to be slightly lower than that for diclosulam. Sorptivity of diclosulam and degradates increased with time. PMID:10995360

  9. 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. PMID:1418936

  10. 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

  11. Stereoselective fate kinetics of chiral neonicotinoid insecticide paichongding in aerobic soils.

    PubMed

    Fu, Qiuguo; Wang, Wei; Wang, Haiyan; Zhang, Jianbo; Shen, Jiajun; Li, Zhong; Ye, Qingfu

    2015-11-01

    Man-made chemicals such as pesticides, when released into the soil environment, are transformed into extractable residue (ER), bound residue (BR), or mineralized. These processes all play a pivotal role in the risk assessment for the use of man-made chemicals. In this study, BR, ER, and mineralization of a novel chiral pesticide, paichongding (IPP), 1-((6-chloropyridin-3-yl)methyl)-7-methyl-8-nitro-5-propoxy-1,2,3,5,6,7-hexahydro-imidazo[1,2-a]pyridine, were investigated in different soils under aerobic conditions. Significant specificity was observed for diastereoisomers of IPP in the formation of BR or mineralization in neutral and alkaline soils. In contrast, no significant difference was found between enantiomers. The overall mineralization was less than 8% of the applied radioactivity and was related to soil pH. Our findings suggest that the environmental fate of chiral pesticides may be influenced by many factors such as soil properties (e.g. pH). More comprehensive and individualized risk assessments should be carried out for individual stereoisomers of a chiral product. PMID:26070081

  12. Mammalian cell-line based toxicological evaluation of paper mill black liquor treated in a soil microcosm by indigenous alkalo-tolerant Bacillus sp.

    PubMed

    Mishra, Monika; Das, Mihir Tanay; Thakur, Indu Shekhar

    2014-02-01

    Organic pollutants present in the soil of a microcosm containing pulp and paper mill black liquor were extracted with hexane/acetone (1:1 v/v) to study the biodegradation and detoxification potential of a Bacillus sp. gas chromatography-mass spectroscopic (GC-MS) analysis performed after biodegradation showed formation of simpler compounds like p-hydroxyhydrocinnamic acid (retention time [RT] 19.3 min), homovanillic acid methyl ester (RT 21.6 min) and 3,5-dimethoxy-p-coumaric alcohol (RT 24.7 min). The methyltetrazolium (MTT) assay for cytotoxicity, 7-ethoxyresorufin-O-deethylase (EROD) assay for dioxin-like behavior and alkaline comet assay for genotoxicity were carried out in the human hepatocarcinoma cell line HuH-7 before and after bacterial treatment. Bioremediation for 15 days reduced toxicity, as shown by a 139-fold increase in black liquor's LC50 value, a 343-fold reduction in benzo(a)pyrene equivalent value and a 5-fold reduction in olive tail moment. The EROD assay positively correlated with both the MTT and comet assays in post biodegradation toxicity evaluation. PMID:24170500

  13. 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.

  14. Degradation of methyl bromide and methyl chloride in soil microcosms: Use of stable C isotope fractionation and stable isotope probing to identify reactions and the responsible microorganisms

    USGS Publications Warehouse

    Miller, L.G.; Warner, K.L.; Baesman, S.M.; Oremland, R.S.; McDonald, I.R.; Radajewski, S.; Murrell, J.C.

    2004-01-01

    Bacteria in soil microcosm experiments oxidized elevated levels of methyl chloride (MeCl) and methyl bromide (MeBr), the former compound more rapidly than the latter. MeBr was also removed by chemical reactions while MeCl was not. Chemical degradation dominated the early removal of MeBr and accounted for more than half of its total loss. Fractionation of stable carbon isotopes during chemical degradation of MeBr resulted in a kinetic isotope effect (KIE) of 59 ?? 7???. Soil bacterial oxidation dominated the later removal of MeBr and MeCl and was characterized by different KIEs for each compound. The KIE for MeBr oxidation was 69 ?? 9??? and the KIE for MeCl oxidation was 49 ?? 3???. Stable isotope probing revealed that different populations of soil bacteria assimilated added 13C-labeled MeBr and MeCl. The identity of the active MeBr and MeCl degrading bacteria in soil was determined by analysis of 16S rRNA gene sequences amplified from 13C-DNA fractions, which identified a number of sequences from organisms not previously thought to be involved in methyl halide degradation. These included Burkholderia , the major clone type in the 13C-MeBr fraction, and Rhodobacter, Lysobacter and Nocardioides the major clone types in the 13C-MeCl fraction. None of the 16S rRNA gene sequences for methyl halide oxidizing bacteria currently in culture (including Aminobacter strain IMB-1 isolated from fumigated soil) were identified. Functional gene clone types closely related to Aminobacter spp. were identified in libraries containing the sequences for the cmuA gene, which codes for the enzyme known to catalyze the initial step in the oxidation of MeBr and MeCl. The cmuA gene was limited to members of the alpha-Proteobacteria whereas the greater diversity demonstrated by the 16S rRNA gene may indicate that other enzymes catalyze methyl halide oxidation in different groups of bacteria. Copyright ?? 2004 Elsevier Ltd.

  15. Degradation of methyl bromide and methyl chloride in soil microcosms: Use of stable C isotope fractionation and stable isotope probing to identify reactions and the responsible microorganisms

    NASA Astrophysics Data System (ADS)

    Miller, Laurence G.; Warner, Karen L.; Baesman, Shaun M.; Oremland, Ronald S.; McDonald, Ian R.; Radajewski, Stefan; Murrell, J. Colin

    2004-08-01

    Bacteria in soil microcosm experiments oxidized elevated levels of methyl chloride (MeCl) and methyl bromide (MeBr), the former compound more rapidly than the latter. MeBr was also removed by chemical reactions while MeCl was not. Chemical degradation dominated the early removal of MeBr and accounted for more than half of its total loss. Fractionation of stable carbon isotopes during chemical degradation of MeBr resulted in a kinetic isotope effect (KIE) of 59 ± 7‰. Soil bacterial oxidation dominated the later removal of MeBr and MeCl and was characterized by different KIEs for each compound. The KIE for MeBr oxidation was 69 ± 9‰ and the KIE for MeCl oxidation was 49 ± 3‰. Stable isotope probing revealed that different populations of soil bacteria assimilated added 13C-labeled MeBr and MeCl. The identity of the active MeBr and MeCl degrading bacteria in soil was determined by analysis of 16S rRNA gene sequences amplified from 13C-DNA fractions, which identified a number of sequences from organisms not previously thought to be involved in methyl halide degradation. These included Burkholderia, the major clone type in the 13C-MeBr fraction, and Rhodobacter, Lysobacter and Nocardioides the major clone types in the 13C-MeCl fraction. None of the 16S rRNA gene sequences for methyl halide oxidizing bacteria currently in culture (including Aminobacter strain IMB-1 isolated from fumigated soil) were identified. Functional gene clone types closely related to Aminobacter spp. were identified in libraries containing the sequences for the cmuA gene, which codes for the enzyme known to catalyze the initial step in the oxidation of MeBr and MeCl. The cmuA gene was limited to members of the alpha-Proteobacteria whereas the greater diversity demonstrated by the 16S rRNA gene may indicate that other enzymes catalyze methyl halide oxidation in different groups of bacteria.

  16. Induction of the Viable but Nonculturable State of Ralstonia solanacearum by Low Temperature in the Soil Microcosm and Its Resuscitation by Catalase

    PubMed Central

    Kong, Hyun Gi; Bae, Ju Young; Lee, Hyoung Ju; Joo, Hae Jin; Jung, Eun Joo; Chung, Eunsook; Lee, Seon-Woo

    2014-01-01

    Ralstonia solanacearum is the causal agent of bacterial wilt on a wide variety of plants, and enters a viable but nonculturable (VBNC) state under stress conditions in soil and water. Here, we adopted an artificial soil microcosm (ASM) to investigate the VBNC state of R. solanacearum induced by low temperature. The culturability of R. solanacearum strains SL341 and GMI1000 rapidly decreased at 4°C in modified ASM (mASM), while it was stably maintained at 25°C in mASM. We hypothesized that bacterial cells at 4°C in mASM are viable but nonculturable. Total protein profiles of SL341 cells at 4°C in mASM did not differ from those of SL341 culturable cells at 25°C in mASM. Moreover, the VBNC cells maintained in the mASM retained respiration activity. Catalase treatment effectively restored the culturability of nonculturable cells in mASM, while temperature increase or other treatments used for resuscitation of other bacteria were not effective. The resuscitated R. solanacearum from VBNC state displayed normal level of bacterial virulence on tomato plants compared with its original culturable bacteria. Expression of omp, oxyR, rpoS, dps, and the 16S rRNA gene quantified by RT-qPCR did not differ significantly between the culturable and VBNC states of R. solanacearum. Our results suggested that the VBNC bacterial cells in mASM induced by low temperature exist in a physiologically unique state. PMID:25296177

  17. EVALUATION AND TESTING OF A PROTOCOL TO DETERMINE THE AEROBIC DEGRADATION POTENTIAL OF HAZARDOUS WASTE CONSTITUENTS IN SOIL

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) in conjunction with the U.S. Department of Agriculture is currently testing a protocol for determine the "Aerobic Degradation Potential of Hazardous Organic Constituents in Soil" to ensure its reliability, accuracy, cost effectivenes...

  18. 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. PMID:20189632

  19. Fungicide Dissipation and Impact on Metolachlor Aerobic Soil Degradation and Soil Microbial Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticides are typically applied as mixtures and or sequentially to soil during crop production. A common scenario is herbicide application at planting followed by sequential fungicide applications post-emergence. Fungicides depending on their spectrum of activity may alter and impact soil microbial...

  20. 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

  1. Arbuscular mycorrhizae alleviate negative effects of zinc oxide nanoparticle and zinc accumulation in maize plants--A soil microcosm experiment.

    PubMed

    Wang, Fayuan; Liu, Xueqin; Shi, Zhaoyong; Tong, Ruijian; Adams, Catharine A; Shi, Xiaojun

    2016-03-01

    ZnO nanoparticles (NPs) are considered an emerging contaminant when in high concentration, and their effects on crops and soil microorganisms pose new concerns and challenges. Arbuscular mycorrhizal (AM) fungi (AMF) form mutualistic symbioses with most vascular plants, and putatively contribute to reducing nanotoxicity in plants. Here, we studied the interactions between ZnO NPs and maize plants inoculated with or without AMF in ZnO NPs-spiked soil. ZnO NPs had no significant adverse effects at 400 mg/kg, but inhibited both maize growth and AM colonization at concentrations at and above 800 mg/kg. Sufficient addition of ZnO NPs decreased plant mineral nutrient acquisition, photosynthetic pigment concentrations, and root activity. Furthermore, ZnO NPs caused Zn concentrations in plants to increase in a dose-dependent pattern. As the ZnO NPs dose increased, we also found a positive correlation with soil diethylenetriaminepentaacetic acid (DTPA)-extractable Zn. However, AM inoculation significantly alleviated the negative effects induced by ZnO NPs: inoculated-plants experienced increased growth, nutrient uptake, photosynthetic pigment content, and SOD activity in leaves. Mycorrhizal plants also exhibited decreased ROS accumulation, Zn concentrations and bioconcentration factor (BCF), and lower soil DTPA-extractable Zn concentrations at high ZnO NPs doses. Our results demonstrate that, at high contamination levels, ZnO NPs cause toxicity to AM symbiosis, but AMF help alleviate ZnO NPs-induced phytotoxicity by decreasing Zn bioavailability and accumulation, Zn partitioning to shoots, and ROS production, and by increasing mineral nutrients and antioxidant capacity. AMF may play beneficial roles in alleviating the negative effects and environmental risks posed by ZnO NPs in agroecosystems. PMID:26761602

  2. Arbuscular mycorrhizal wheat inoculation promotes alkane and polycyclic aromatic hydrocarbon biodegradation: Microcosm experiment on aged-contaminated soil.

    PubMed

    Ingrid, Lenoir; Lounès-Hadj Sahraoui, Anissa; Frédéric, Laruelle; Yolande, Dalpé; Joël, Fontaine

    2016-06-01

    Very few studies reported the potential of arbuscular mycorrhizal symbiosis to dissipate hydrocarbons in aged polluted soils. The present work aims to study the efficiency of arbuscular mycorrhizal colonized wheat plants in the dissipation of alkanes and polycyclic aromatic hydrocarbons (PAHs). Our results demonstrated that the inoculation of wheat with Rhizophagus irregularis allowed a better dissipation of PAHs and alkanes after 16 weeks of culture by comparison to non-inoculated condition. These dissipations observed in the inoculated soil resulted from several processes: (i) a light adsorption on roots (0.5% for PAHs), (ii) a bioaccumulation in roots (5.7% for PAHs and 6.6% for alkanes), (iii) a transfer in shoots (0.4 for PAHs and 0.5% for alkanes) and mainly a biodegradation. Whereas PAHs and alkanes degradation rates were respectively estimated to 12 and 47% with non-inoculated wheat, their degradation rates reached 18 and 48% with inoculated wheat. The mycorrhizal inoculation induced an increase of Gram-positive and Gram-negative bacteria by 56 and 37% compared to the non-inoculated wheat. Moreover, an increase of peroxidase activity was assessed in mycorrhizal roots. Taken together, our findings suggested that mycorrhization led to a better hydrocarbon biodegradation in the aged-contaminated soil thanks to a stimulation of telluric bacteria and hydrocarbon metabolization in mycorrhizal roots. PMID:26995451

  3. The concurrent kinetics of N uptake by soil microbes and western hemlock (Tsuga heterophylla) seedlings: a microcosm study

    NASA Astrophysics Data System (ADS)

    Grenon, Frank; Bradley, Robert; Titus, Brian

    2014-05-01

    There is disagreement over the relative ability of microbes and plants to compete for soil N. Empirical data are needed, therefore, to develop models that can be applied for specific plant species across different soil conditions. We grew western hemlock (Tsuga heterophylla (Raf.) Sarg) seedlings in humus collected from old-growth forest plots (high available C) and from adjacent clearcut plots (low available C). We injected the rhizospheres with either 15N-labelled NH4+ or 15N-labelled amino acid solutions, over a wide range of N concentrations. The uptake of these N compounds by soil microbes and seedlings was assessed 4 h after injection. Microbial uptake rates of NH4+-N were best described by a linear models, whereas microbial uptake of amino acid-N as well as seedling N uptake were best described by asymptotic models. Microbial uptake rates were several orders of magnitude greater than seedling uptake rates, except at low concentrations that are typical under field situations. The provenance of the humus also had significant effects on N uptake kinetics by microbes and seedlings, which were consistent with the available C status of each humus type. Results suggest that differences in N uptake kinetics between plants and microbes are complementary functions that may confer resistance and resilience to forest ecosystems.

  4. Extending the Marine Microcosm Laboratory

    ERIC Educational Resources Information Center

    Ryswyk, Hal Van; Hall, Eric W.; Petesch, Steven J.; Wiedeman, Alice E.

    2007-01-01

    The traditional range of marine microcosm laboratory experiments is presented as an ideal environment to teach the entire analysis process. The microcosm lab provides student-centered approach with opportunities for collaborative learning and to develop critical communication skills.

  5. 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

  6. MICROCOSM AND IN-SITU FIELD STUDIES OF ENHANCED BIOTRANSFORMATION OF TRICHLOROETHYLENE BY PHENOL-UTILIZING MICROORGANISMS

    EPA Science Inventory

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms a...

  7. 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

  8. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    PubMed

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong

    2015-04-28

    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. PMID:25661171

  9. Biotic and Abiotic Degradation of CL-20 and RDX in Soils

    SciTech Connect

    Crocker, Fiona H.; Thompson, Karen T.; Szecsody, Jim E.; Fredrickson, Herbert L.

    2005-11-01

    The caged cyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a new explosive that has the potential to replace existing military explosives, but little is known about its environmental toxicity, transport, and fate. We quantified and compared the aerobic environmental fate of CL-20 to the widely used cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in surface and subsurface soil microcosms. Soil-free controls and biologically mediated processes. Both abiotic and biological processes significantly degraded CL-20 in all soils examined. Apparent abiotic, first-order degradation rates (k) for CL-20 were not significantly different between soil-free controls (0.018 < k < 0.030 d-1) and biologically attenuated soil controls (0.003 soil microcosms significantly increased CL-20 degradation rates (0.068 < k <1.22 d-1). Extents of mineralization of 14C–CL-20 to 14CO2 in biologically active soil microcosms were 41.1 to 55.7%, indicating that the CL-20 cage was broken, since all carbons are part of the heterocyclic cage. Under aerobic conditions, abiotic degradation rates of RDX were generally slower (0 < k < 0.032 d-1) than abiotic CL-20 degradation rates. In biologically active soil microcosms amended with glucose aerobic RDX degradation rates varied between 0.010 and 0.474 d-1. Biodegradation was a key factor in determining the environmental fate of RDX, while a combination of biotic and abiotic processes was important with CL-20. Our data suggest that CL-20 should be less recalcitrant than RDX in aerobic soils.

  10. Is it clean or contaminated soil? Using petrogenic versus biogenic GC-FID chromatogram patterns to mathematically resolve false petroleum hydrocarbon detections in clean organic soils: a crude oil-spiked peat microcosm experiment.

    PubMed

    Kelly-Hooper, Francine; Farwell, Andrea J; Pike, Glenna; Kennedy, Jocelyn; Wang, Zhendi; Grunsky, Eric C; Dixon, D George

    2013-10-01

    The Canadian Council of Ministers of the Environment (CCME) reference method for the Canada-wide standard (CWS) for petroleum hydrocarbon (PHC) in soil provides chemistry analysis standards and guidelines for the management of contaminated sites. However, these methods can coextract natural biogenic organic compounds (BOCs) from organic soils, causing false exceedences of toxicity guidelines. The present 300-d microcosm experiment used CWS PHC tier 1 soil extraction and gas chromatography-flame ionization detector (GC-FID) analysis to develop a new tier 2 mathematical approach to resolving this problem. Carbon fractions F2 (C10-C16), F3 (C16-C34), and F4 (>C34) as well as subfractions F3a (C16-C22) and F3b (C22-C34) were studied in peat and sand spiked once with Federated crude oil. These carbon ranges were also studied in 14 light to heavy crude oils. The F3 range in the clean peat was dominated by F3b, whereas the crude oils had approximately equal F3a and F3b distributions. The F2 was nondetectable in the clean peat but was a significant component in crude oil. The crude oil–spiked peat had elevated F2 and F3a distributions. The BOC-adjusted PHC F3 calculation estimated the true PHC concentrations in the spiked peat. The F2:F3b ratio of less than 0.10 indicated PHC absence in the clean peat, and the ratio of greater than or equal to 0.10 indicated PHC presence in the spiked peat and sand. Validation studies are required to confirm whether this new tier 2 approach is applicable to real-case scenarios. Potential adoption of this approach could minimize unnecessary ecological disruptions of thousands of peatlands throughout Canada while also saving millions of dollars in management costs. PMID:23703885

  11. 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

  12. Influence of water table on carbon dioxide, carbon monoxide, and methane fluxes from taiga bog microcosms

    SciTech Connect

    Funk, D.W.; Pullmann, E.R.; Peterson, K.M.

    1994-09-01

    Hydrological changes, particularly alterations in water table level, may largely overshadow the more direct effects of global temperature increase upon carbon cycling in arctic and subarctic wetlands. Frozen cores (n=40) of intact soils and vegetation were collected from a bog near Fairbanks, Alaska, and fluxes of CO{sub 2}, CH{sub 4}, and Co in response to water table variation were studied under controlled conditions in the Duke University phytotron. Core microcosms thawed to a 20-cm depth over 30 days under a 20 hour photoperiod with a day/night temperature regime of 20/10{degrees}C. After 30 days the water table in 20 microcosms was decreased from the soil surface to -15 cm and maintained at the soil surface in 20 control cores. Outward fluxes of CO{sub 2} (9-16 g m{sup -2}d{sup -1}) and CO (3-4 mg m{sup -2}d{sup -1}) were greatest during early thaw and decreased to near zero for both gases before the water table treatment started. Lower water table tripled CO{sub 2} flux to the atmosphere when compared with control cores. Carbon monoxide was emitted at low rates from high water table cores and consumed by low water table cores. Methane fluxes were low (<1 mg m{sup -2}d{sup -1}) in all cores during thaw. High water table cores increased CH{sub 4} flux to 8-9 mg m{sup -2}d{sup -1} over 70 days and remained high relative to the low water table cores (<0.74 mg m{sup -2}d{sup -1}). Although drying of wetland taiga soils may decrease CH{sub 4} emissions to the atmosphere, the associated increase in CO{sub 2} due to aerobic respiration will likely increase the global warming potential of gas emissions from these soils. 43 refs., 4 figs.

  13. Spatial distribution of hydroxylamine and its role in aerobic N2O formation in a Norway spruce forest soil

    NASA Astrophysics Data System (ADS)

    Liu, S.; Weymann, D.; Gottselig, N.; Wiekenkamp, I.; Vereecken, H.; Brueggemann, N.

    2014-12-01

    Hydroxylamine (HA) as a crucial intermediate in the microbial oxidation of ammonium to nitrite (nitrification) is a potential precursor of abiotic N2O formation in the soil. However, the determination of HA concentration in natural soil samples has not been reported until now. Here, we determined the HA concentrations in organic (Oh) and mineral (Ah) layers of 135 soil samples collected from a spruce forest (Wüstebach, Eifel National Park, Germany) using a novel approach, based on the fast extraction of HA from the soil at a pH of 1.7, the oxidation of HA to N2O with Fe3+, and the analysis of produced N2O using gas chromatography (GC). Meanwhile, N2O emission rates were determined by means of aerobic laboratory incubations of 3-g soil in 22-mL vials. Subsequently, the spatial distribution of soil HA concentrations and N2O emission rates in the Oh and Ah layers of the whole sampling area were analyzed using a geostatistical approach. The correlations among soil HA, N2O emission rate, pH, soil C, N, Fe, Mn and soil water content (SWC) were further explored. The HA concentrations ranged from 0.3-44.6 μg N kg-1 dry soil and 0.02-16.2 μg N kg-1 dry soil in the Oh and the Ah layer, respectively. The spatial distribution of HA was similar in both layers, with substantial spatial variability dependent on soil type, tree density and distance to a stream. For example, HA concentration was greater at locations with a thick litter layer or at locations close to the stream. The average N2O emission rate in the Oh layer was 0.38 μg N kg-1 dry soil h-1, 10-fold larger than in the Ah layer. Interestingly, N2O emission rate exhibited high correlation with soil HA content in the Oh (R2 = 0.65, p < 0.01) and Ah (R2 = 0.45, p < 0.05) layer. The results demonstrated that HA is a crucial component for aerobic N2O formation and emission in spruce forest soils. Moreover, HA concentration was negatively correlated with pH and positively correlated with SWC in the Oh layer, while

  14. 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

  15. 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.

  16. 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

  17. [Research advances in aerobic denitrifiers].

    PubMed

    Wang, Wei; Cai, Zu-cong; Zhong, Wen-hui; Wang, Guo-xiang

    2007-11-01

    This paper reviewed the varieties and characteristics of aerobic denitrifiers, their action mechanisms, and the factors affecting aerobic denitrification. Aerobic denitrifiers mainly include Pseudomonas, Alcaligenes, Paracoccus and Bacillus, which are either aerobic or facultative aerobic, and heterotrophic. They can denitrify under aerobic conditions, with the main product being N2O. They can also convert NH4+ -N to gas product. The nitrate reductase which catalyzes the denitrification is periplasmic nitrate reductase rather than membrane-bound nitrate reductase. Dissolved oxygen concentration and C/N ratio are the main factors affecting aerobic denitrification. The main methods for screening aerobic denitrifiers, such as intermittent aeration and selected culture, were also introduced. The research advances in the application of aerobic denitrifiers in aquaculture, waste water processing, and bio-degradation of organic pollutants, as well as the contributions of aerobic denitrifiers to soil nitrogen emission were summarized. PMID:18260473

  18. Ecotoxicological assessment of biosolids by microcosms.

    PubMed

    Groth, Vitor Avelar; Carvalho-Pereira, Ticiana; da Silva, Eduardo Mendes; Niemeyer, Júlia Carina

    2016-10-01

    Biosolids have been applied as soil amendments to improve and maintain the soil fertility and faster plant growth. In spite of its beneficial use, the potential risks of land disposal should be analyzed, considering potential ecological receptors in soil and water. This work describes the use of an early warning laboratory microcosm system to evaluate the integrated ecotoxicological potential of two biosolids: BIO-1 and BIO-2 (18 and 28 months after landfarming, respectively), from an effluent treatment station in a petrochemical and industrial district. The endpoints related to habitat function were: a) germination, growth and biomass of Phaseolus vulgaris; b) survival, biomass and number of cocoons of Eisenia andrei (Oligochaeta) and; c) reproduction of Folsomia candida (Collembola). The retention function was evaluated by testing the leachates using the tropical cladoceran Latonopsis australis (Cladocera) in a 48-h acute toxicity test, and growth of the aquatic plant Lemna minor in a 7-d chronic test. Tropical artificial soil (TAS) and a natural soil (NS) from the region were used as control soils. Results showed no chronic toxicity of BIO-1 and BIO-2 to the soil organisms tested, but acute toxicity of BIO-1 in the leachate for 50% of L. australis, and chronic toxicity of both biosolid leachates to L. minor (inhibition of growth rate), indicating potential risks to aquatic ecosystems. The results confirmed the ability of this microcosm system as a rapid tool to assess biosolid toxicity over time and its potential for hazardous waste characterization in environmental risk assessment, in a screening phase. PMID:27448314

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    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 23 μg (mg cells)- 1) and methane (0.14 and 8.4 μg (mg cells)- 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).

  1. 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.

  2. 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

  3. Investigating the effects of anaerobic and aerobic post-treatment on quality and stability of organic fraction of municipal solid waste as soil amendment.

    PubMed

    Abdullahi, Y A; Akunna, J C; White, N A; Hallett, P D; Wheatley, R

    2008-12-01

    The use of OFMSW for biogas and compost production is considered as a sustainable strategy in saving valuable landfill space while producing valuable product for soil application. This study examines the effects of anaerobic and aerobic post-treatment of OFMSW on the stability of anaerobic digestate and compost and soil quality using seed germination tests. Anaerobic digestion of OFMSW was carried out for fifteen days after which the residual anaerobic digestate was subjected to aerobic post-treatment for seventy days. Seed germination tests showed that fresh feedstock and digestates collected during anaerobic digestion and during the early stages of aerobic post-treatment were phytotoxic. However, phytotoxic effects were not observed in soils amended with the fully stabilised anaerobic digestate compost, ADC. It was also found that seed germination increases with dilution and incubation time, suggesting that lower soil application rates and longer lag periods between soil application of ADC and planting can reduce the amount of biodegradable organics in the ADC, thus enhancing the benefits of ADC as soil amendment. PMID:18511266

  4. 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...

  5. 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...

  6. A Natal Microcosm

    NASA Technical Reports Server (NTRS)

    2004-01-01

    In the quest to better understand the birth of stars and the formation of new worlds, astronomers have used NASA's Spitzer Space Telescope to examine the massive stars contained in a cloudy region called Sharpless 140. This cloud is a fascinating microcosm of a star-forming region since it exhibits, within a relatively small area, all of the classic manifestations of stellar birth.

    Sharpless 140 lies almost 3000 light-years from Earth in the constellation Cepheus. At its heart is a cluster of three deeply embedded young stars, which are each several thousand times brighter than the Sun. Though they are strikingly visible in this image from Spitzer's infrared array camera, they are completely obscured in visible light, buried within the core of the surrounding dust cloud.

    The extreme youth of at least one of these stars is indicated by the presence of a stream of gas moving at high velocities. Such outflows are signatures of the processes surrounding a star that is still gobbling up material as part of its formation.

    The bright red bowl, or arc, seen in this image traces the outer surface of the dense dust cloud encasing the young stars. This arc is made up primarily of organic compounds called polycyclic aromatic hydrocarbons, which glow on the surface of the cloud. Ultraviolet light from a nearby bright star outside of the image is 'eating away' at these molecules. Eventually, this light will destroy the dust envelope and the masked young stars will emerge.

    This false-color image was taken on Oct. 11, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

  7. 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

  8. 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

  9. Using Microcosms To Teach about the Environment.

    ERIC Educational Resources Information Center

    Kaufman, Donald G.; Taylor, Lisa

    A microcosm is a small, completely sealed, self-sustaining ecosystem. Once a microcosm has been sealed in a transparent container, only light and some heat can enter and only excess heat can leave. This manual describes how to set up aquatic microcosms using glass jars and little or no collecting equipment. The activities can be tailored to suit…

  10. Microcosm and in situ field studies of enhanced biotransformation of trichloroethylene by phenol-utilizing microorganisms.

    PubMed Central

    Hopkins, G D; Semprini, L; McCarty, P L

    1993-01-01

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms amended with phenol or toulene were equally effective in removing c-DCE (> 90%) followed by TCE (60 to 70%), while the microcosm fed methane was most effective in removing t-DCE (> 90%). The microcosm fed ammonia was the least effective. None of the microcosms effectively degraded 1,1,1-trichloroethane. At the Moffett Field groundwater test site, in situ removal of c-DCE and TCE coincided with biostimulation through phenol and oxygen injection and utilization, with c-DCE removed more rapidly than TCE. Greater TCE and c-DCE removal was observed when the phenol concentration was increased. Over 90% removal of c-DCE and TCE was observed in the 2-m biostimulated zone. This compares with 40 to 50% removal of c-DCE and 15 to 25% removal of TCE achieved by methane-grown microorganisms previously evaluated in an adjacent in situ test zone. The in situ removal with phenol-grown microorganisms agrees qualitatively with the microcosm studies, with the rates and extents of removal ranked as follows: c-DCE > TCE > t-DCE. These studies demonstrate the potential for in situ TCE bioremediation using microorganisms grown on phenol. PMID:8357259

  11. PRODUCTION CYCLES IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Four 700-liter cylindrical containers were filled with demineralized water, enriched with nutrients, and inoculated with 3.5-liter lakewater samples. The microcosms were maintained at a temperature of 18C under a 12:12 L:D cycle for 6 months and several manipulations of their tro...

  12. Know Thyself: Macrocosm and Microcosm

    ERIC Educational Resources Information Center

    Tubbs, Nigel

    2011-01-01

    There was a time when, in the Liberal Arts, philosophy and education enjoyed the most intimate and productive relationship. Drawing together philosophy and nature they sought to understand the greatest of human mysteries. This meant thinking about both the macrocosm and the microcosm and especially the relation between them. In this relation lies…

  13. Uranium transformations in static microcosms.

    SciTech Connect

    Kelly, S. D.; Wu, W.; Yang, F.; Criddle, C.; Marsh, T. L.; O'Loughlin, E. J.; Ravel, B.; Watson, D.; Jardine, P. M.; Kemner, K. M.; Stanford Univ.; Michigan State Univ.; ORNL; BNL; EXAFS Analysis

    2010-01-01

    Elucidation of complex biogeochemical processes and their effects on speciation of U in the subsurface is critical for developing remediation strategies with an understanding of stability. We have developed static microcosms that are similar to bioreduction process studies in situ under laminar flow conditions or in sediment pores. Uranium L{sub 3}-edge X-ray absorption near-edge spectroscopy analysis with depth in the microcosms indicated that transformation of U{sup VI} to U{sup IV} occurred by at least two distinct processes. Extended X-ray absorption fine structure (EXAFS) analysis indicated that initial U{sup VI} species associated with C- and P-containing ligands were transformed to U{sup IV} in the form of uraninite and U associated with Fe-bound ligands. Microbial community analysis identified putative Fe{sup III} and sulfate reducers at two different depths in the microcosms. The slow reduction of U{sup VI} to U{sup IV} may contribute the stability of U{sup IV} within microcosms at 11 months after a decrease in bioreducing conditions due to limited electron donors.

  14. Enhanced litter input rather than changes in litter chemistry drive soil carbon and nitrogen cycles under elevated CO2: a microcosm study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated CO2 has been shown to stimulate plant productivity and change litter chemistry. These changes in substrate availability may then alter soil microbial processes and possibly lead to feedback effects on N availability. However, the strength of this feed back, and even its direction, remain un...

  15. Responses of mcrA and pmoA Gene Copies and Methane Fluxes to Soil Temperature Changes in Rice Microcosms

    NASA Astrophysics Data System (ADS)

    Sithole, A.; Flores, G. E.; Reysenbach, A. L.; Shearer, M. J.; Butenhoff, C. L.; Khalil, A. M.

    2010-12-01

    Methane generated from microbial activity in rice fields and wetlands is a major source of atmospheric methane, a potent greenhouse gas. The potency of this gas makes understanding the effect of global warming on methane emissions a key challenge in projecting the impact of future global warming. Methane is actively generated in-situ by methanogens, who use H2 and either CO2 or acetate produced by other organisms that degrade the organics. Our work determined the feedback of global warming on methane emissions from rice agriculture by looking at the links between populations of microbial consortia and increased soil temperature conducive to both methane production and consumption within the rhizosphere. Duplicate vertical soil profile samples were collected from temperature-controlled tubs with rice plants. The four waterbaths, set at different temperatures, each contained four tubs, with one bare tub (control) and three planted with rice. The soil samples were immediately frozen and stored at -80 deg. C, and were homogenized before DNA extraction. Quantitative Polymerase Chain Reaction (qPCR) was used to measure the concentrations of the methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) genes in the extracted soil DNA. The mcrA and pmoA were used as the functional gene probes for methanogens (methane producing bacteria) and methanotrophs (methane oxidizing bacteria), respectively. An FID-equipped Gas Chromatography was used to measure the methane concentration in air samples collected from acrylic flux chambers. Results from our experiments showed that methanogens and methanotrophs were preferentially located to certain regions of the soil profile under different temperature regimes. Our results also indicated that higher global temperatures will increase methanogens populations, but not as much for methanotrophs, and hence increase methane fluxes from rice agriculture. Considering that the mechanisms of methane production in rice

  16. Enzyme activities of aerobic lignocellulolytic bacteria isolated from wet tropical forest soils.

    PubMed

    Woo, Hannah L; Hazen, Terry C; Simmons, Blake A; DeAngelis, Kristen M

    2014-02-01

    Lignocellulolytic bacteria have promised to be a fruitful source of new enzymes for next-generation lignocellulosic biofuel production. Puerto Rican tropical forest soils were targeted because the resident microbes decompose biomass quickly and to near-completion. Isolates were initially screened based on growth on cellulose or lignin in minimal media. 75 Isolates were further tested for the following lignocellulolytic enzyme activities: phenol oxidase, peroxidase, β-d-glucosidase, cellobiohydrolase, β-xylopyranosidase, chitinase, CMCase, and xylanase. Cellulose-derived isolates possessed elevated β-d-glucosidase, CMCase, and cellobiohydrolase activity but depressed phenol oxidase and peroxidase activity, while the contrary was true of lignin isolates, suggesting that these bacteria are specialized to subsist on cellulose or lignin. Cellobiohydrolase and phenol oxidase activity rates could classify lignin and cellulose isolates with 61% accuracy, which demonstrates the utility of model degradation assays. Based on 16S rRNA gene sequencing, all isolates belonged to phyla dominant in the Puerto Rican soils, Proteobacteria, Firmicutes, and Actinobacteria, suggesting that many dominant taxa are capable of the rapid lignocellulose degradation characteristic of these soils. The isolated genera Aquitalea, Bacillus, Burkholderia, Cupriavidus, Gordonia, and Paenibacillus represent rarely or never before studied lignolytic or cellulolytic species and were undetected by metagenomic analysis of the soils. The study revealed a relationship between phylogeny and lignocellulose-degrading potential, supported by Kruskal-Wallis statistics which showed that enzyme activities of cultivated phyla and genera were different enough to be considered representatives of distinct populations. This can better inform future experiments and enzyme discovery efforts. PMID:24238986

  17. 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.

  18. Assessment of functional and genetic diversity of aerobic endospore forming Bacilli from rhizospheric soil of Phyllanthus amarus L.

    PubMed

    Kadyan, Sangeeta; Panghal, Manju; Kumar, Sandeep; Singh, Khushboo; Yadav, Jaya Parkash

    2013-09-01

    Fifty two aerobic and endospore forming Bacilli (AEFB) strains were recovered from rhizospheric soil of Phyllanthus amarus. Morphological, biochemical and molecular characterization by 16S rDNA gene sequencing has shown that these bacterial strains belong to six different genera of AEFB i.e. Bacillus, Brevibacillus, Lysinibacillus, Paenibacillus, Terribacillus and Jeotgalibacillus. Analysis of their PGP activities has shown that 92.30 % strains produced indole acetic acid hormone, 86.53 % of the strains solubilized Phosphate and 44.23 % strains produced siderophore. Chitinase production activity was shown by 42.30 % of the strains and 21.15 % of the strains produced 1-amino cyclopropane-1-carboxylate (ACC) deaminase. 46.15 % of isolates have shown antagonistic activity against common fungal pathogen of the plant i.e. Corynespora cassiicola. Among all of the isolated strains B. Cereus JP44SK22 and JP44SK42 have shown all of the six plant growth promoting traits tested. B. megaterium strains (JP44SK18 and JP44SK35), Lysinibacillus sphaericus strains (JP44SK3 and JP44SK4) and Brevibacillus laterosporus strain JP44SK51 have also shown multiple PGP activities except ACC deaminase production activity. In the present study bacterial strain belonging to genera Jeotgalibacillus sp. JP44SK37 has been reported first time as a member of rhizospheric soil habitat and has also shown PGP activities. It can be concluded that Rhizosphere of P. amarus has harboured a good diversity of AEFB bacterial strains having a lot of biofertilizing and biocontrol abilities. PMID:23526192

  19. Metagenomic and functional analyses of the consequences of reduction of bacterial diversity on soil functions and bioremediation in diesel-contaminated microcosms

    PubMed Central

    Jung, Jaejoon; Philippot, Laurent; Park, Woojun

    2016-01-01

    The relationship between microbial biodiversity and soil function is an important issue in ecology, yet most studies have been performed in pristine ecosystems. Here, we assess the role of microbial diversity in ecological function and remediation strategies in diesel-contaminated soils. Soil microbial diversity was manipulated using a removal by dilution approach and microbial functions were determined using both metagenomic analyses and enzymatic assays. A shift from Proteobacteria- to Actinobacteria-dominant communities was observed when species diversity was reduced. Metagenomic analysis showed that a large proportion of functional gene categories were significantly altered by the reduction in biodiversity. The abundance of genes related to the nitrogen cycle was significantly reduced in the low-diversity community, impairing denitrification. In contrast, the efficiency of diesel biodegradation was increased in the low-diversity community and was further enhanced by addition of red clay as a stimulating agent. Our results suggest that the relationship between microbial diversity and ecological function involves trade-offs among ecological processes, and should not be generalized as a positive, neutral, or negative relationship. PMID:26972977

  20. Metagenomic and functional analyses of the consequences of reduction of bacterial diversity on soil functions and bioremediation in diesel-contaminated microcosms.

    PubMed

    Jung, Jaejoon; Philippot, Laurent; Park, Woojun

    2016-01-01

    The relationship between microbial biodiversity and soil function is an important issue in ecology, yet most studies have been performed in pristine ecosystems. Here, we assess the role of microbial diversity in ecological function and remediation strategies in diesel-contaminated soils. Soil microbial diversity was manipulated using a removal by dilution approach and microbial functions were determined using both metagenomic analyses and enzymatic assays. A shift from Proteobacteria- to Actinobacteria-dominant communities was observed when species diversity was reduced. Metagenomic analysis showed that a large proportion of functional gene categories were significantly altered by the reduction in biodiversity. The abundance of genes related to the nitrogen cycle was significantly reduced in the low-diversity community, impairing denitrification. In contrast, the efficiency of diesel biodegradation was increased in the low-diversity community and was further enhanced by addition of red clay as a stimulating agent. Our results suggest that the relationship between microbial diversity and ecological function involves trade-offs among ecological processes, and should not be generalized as a positive, neutral, or negative relationship. PMID:26972977

  1. Key high molecular weight PAH-degrading bacteria in a soil consortium enriched using a sand-in-liquid microcosm system.

    PubMed

    Tauler, Margalida; Vila, Joaquim; Nieto, José María; Grifoll, Magdalena

    2016-04-01

    A novel biphasic system containing mineral medium and sand coated with a biologically weathered creosote-PAH mixture was developed to specifically enrich the high molecular weight polycyclic aromatic hydrocarbon (HMW PAH)-degrading community from a creosote-polluted soil. This consortium (UBHP) removed 70 % of the total HMW PAHs and their alkyl-derivatives in 12 weeks. Based on a combined culture-dependent/independent approach, including clone library analysis, detection of catabolic genes, metabolomic profiles, and characterization of bacterial isolates, 10 phylotypes corresponding to five major genera (Sphingobium, Sphingomonas, Achromobacter, Pseudomonas, and Mycobacterium) were pointed out as key players within the community. In response to exposure to different single PAHs, members of sphingomonads were associated to the utilization of phenanthrene, fluoranthene, benzo[a]anthracene, and chrysene, while the degradation of pyrene was mainly associated to low-abundance mycobacteria. In addition to them, a number of uncultured phylotypes were detected, being of special relevance a group of Gammaproteobacteria closely related to a group previously associated with pyrene degradation that were here related to benzo(a)anthracene degradation. The overall environmental relevance of these phylotypes was confirmed by pyrosequencing analysis of the microbial community shift in the creosote-polluted soil during a lab-scale biostimulation. PMID:26637425

  2. Development of microorganisms in the chernozem under aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Polyanskaya, L. M.; Gorbacheva, M. A.; Milanovskii, E. Yu.; Zvyagintsev, D. G.

    2010-03-01

    A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in different horizons of a chernozem. It was revealed that, under aerobic conditions, all the microorganisms grow irrespective of the soil horizon; fungi and bacteria grow at the first succession stages, and actinomycetes grow at the last stages. It was shown that, in the case of a simulated anaerobiosis commonly used to study anaerobic populations of bacteria, the mycelium of micromycetes grows in the upper part of the chernozem’s A horizon. Under anaerobic conditions, the peak of the mycelium development is shifted from the 3rd to 7th days (typical for aerobic conditions) to the 7th to 15th days of incubation. The level of mycelium length’s stabilization under aerobic and anaerobic conditions also differs: it is higher or lower than the initial one, respectively. Under anaerobic conditions, the growth of fungal mycelium, bacteria, and actinomycetes in the lower part of the A horizon and in the B horizon is extremely weak. There was not any observed growth of actinomycetes in all the chernozem’s horizons under anaerobic conditions.

  3. 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

  4. Bioaccumulation and toxicity of copper in outdoor freshwater microcosms.

    PubMed

    Hoang, Tham C; Pryor, Rachel L; Rand, Gary M; Frakes, Robert A

    2011-05-01

    This study characterizes the effects of copper (Cu) on Florida apple snails (Pomacea paludosa) and mosquito fish (Gambusia affinis) using a replicated outdoor microcosm design. Soils used in this study were collected from two Cu-enriched citrus agricultural sites in South Florida (Agler property (AGLR) in St. Lucie County and Sunrise Boys property (SRB) in Palm Beach County) and a reference site (Equus property) in St. Lucie County. The study included a 5-week aging phase, an 11 month exposure phase, and a 3 month post-treatment (exposure) phase. The aging phase was initiated by flooding agricultural soils with rainwater in 4 m(3) fiberglass microcosm tanks. Introducing juvenile apple snails (≤7 d old) and mosquito fish (2-3 cm) into the microcosm tanks initiated the exposure phase. Survival, growth, and reproduction of apple snails and fish, and Cu uptake in apple snails, fish, and periphyton were determined in this study. Water chemistry (e.g., dissolved Cu concentration, dissolved organic carbon and dissolved oxygen concentrations, pH, hardness, alkalinity, etc.) was measured daily or weekly during the study. Initial soil Cu concentrations in Equus, SRB, and AGLR microcosms were 7, 55, and 99 mg/kg dw, respectively. Dissolved Cu concentrations in Equus, SRB and AGLR microcosms at the beginning of the study were 3, 82, and 43 μg/L, respectively and decreased to low saturation levels of about ≤9 μg/L Cu after the first 3 months of the study. The decrease of dissolved Cu concentrations was likely due to the dilution of rainwater. Snail and fish mortality appeared to be higher in SRB microcosms than in Equus and AGLR microcosms. There was no significant difference in growth of the snails between treatments. Snail growth data followed the von Bertalanffy Model. The maximum shell length, shell height, and shell width of the snails calculated by the von Bertalanffy Model (L(∞)) were 2.76, 2.05, and 2.18 cm, respectively. The maximum wet weight was 9.38 g

  5. 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

  6. An evaluation of aerobic and anaerobic composting of banana peels treated with different inoculums for soil nutrient replenishment.

    PubMed

    Kalemelawa, Frank; Nishihara, Eiji; Endo, Tsuneyoshi; Ahmad, Zahoor; Yeasmin, Rumana; Tenywa, Moses M; Yamamoto, Sadahiro

    2012-12-01

    This study sought to evaluate the efficacy of aerobic and anaerobic composting of inoculated banana peels, and assess the agronomic value of banana peel-based compost. Changes in the chemical composition under aerobic and anaerobic conditions were examined for four formulations of banana peel-based wastes over a period of 12 weeks. The formulations i.e. plain banana peel (B), and a mixture with either cow dung (BC), poultry litter (BP) or earthworm (BE) were separately composted under aerobic and anaerobic conditions under laboratory conditions. Inoculation with either cow dung or poultry litter significantly facilitated mineralization in the order: BP>BC>B. The rate of decomposition was significantly faster under aerobic than in anaerobic composting conditions. The final composts contained high K (>100 g kg(-1)) and TN (>2%), indicating high potential as a source of K and N fertilizer. PMID:22608289

  7. Rate of aerobic nitrogen transformations in six acid climax forest soils and the effect of phosphorus and CaCO3

    SciTech Connect

    Sahrawat, K.L.; Keeney, D.R.; Adams, S.S.

    1985-09-01

    Nitrogen transformations (mineralization, nitrification, and nitrous oxide production) were evaluated in acid forest floor soils collected from six climax forest sites on Blackhawk Island, Wisconsin. Soils' acidity (CaCl2) ranged from pH 3.9 to 5.1, and organic matter concentrations varied from 2.4 to 59.0 percent. The samples were incubated aerobically for 4 weeks at 30C under field moist conditions. Treatments were: control; 100 mg P (as KH2PO4) kg soil; CaCO3; and P with CaCO3. Nitrification of mineralized N ranged from nearly complete in the SM Alfisol to almost non-existent in the Histosol. Addition of P had little effect on ammonification or nitrification. Liming, however, greatly enhanced ammonification on nonnitrifying or slowly nitrifying soils and both ammonification and nitrification in nitrifying soils. Adding P and lime together did not affect N transformations compared to liming alone. Nitrous oxide emission rates in the soils were related to nitrification. From 0.03 to 0.3 percent of the NH4-N nitrified was released as N2O-N. Phosphorus addition had little effect but liming increased N2O emission rates in soil where nitrification was also enhanced.

  8. Evaluation of terrestrial microcosms for detection, fate, and survival analysis of genetically engineered microorganisms and their recombinant genetic material

    SciTech Connect

    Fredrickson, J.K.; Seidler, R.J.

    1989-02-01

    The research included in this document represents the current scientific information available regarding the applicability of terrestrial microcosms and related methodologies for evaluating detection methods and the fate and survival of microorganisms in the environment. The three terrestrial microcosms described in this document were used to evaluate the survival and fate of recombinant bacteria in soils and in association with plant surfaces and insects and their transport through soil with percolating water and root systems, and to test new methods and procedures to improve detection and enumeration of bacteria in soil. Simple (potting soil composed of peat mix and perlite, lacking environmental control and monitoring) and complex microcosms (agricultural soil with partial control and monitoring of environmental conditions) were demonstrated to be useful tools for preliminary assessments of microbial viability in terrestrial ecosystems. These studies evaluated the survival patterns of Enterobacter cloacae (pBR322) in soil and on plant surfaces and the ingestion of this same microorganism by cutworms and survival in the foregut and frass. The Versacore microcosm design was used to monitor the fate and competitiveness of genetically engineered bacteria in soil. Both selective media and gene probes were used successfully to follow the fate of two recombinant Pseudomonas sp. introduced into Versacore microcosms. Intact soil-core microcosms were employed to evaluate the fate and transport of genetically altered Azospirillum sp. and Pseudomonas sp. in soil and the plant rhizosphere. The usefulness of these various microcosms as a tool for risk assessment is underscored by the ease in obtaining soil from a proposed field release site to evaluate subsequent GEM fate and survival.

  9. Fate of neptunium in an anaerobic, methanogenic microcosm.

    SciTech Connect

    Banaszak, J. E.

    1998-12-21

    Neptunium is found predominantly as Np(IV) in reducing environments, but Np(V) in aerobic environments. However, currently it is not known how the interplay between biotic and abiotic processes affects Np redox speciation in the environment. In order to evaluate the effect of anaerobic microbial activity on the fate of Np in natural systems, Np(V) was added to a microcosminoculated with anaerobic sediments from a metal-contaminated fresh water lake. The consortium included metal-reducing, sulfate-reducing, and methanogenic microorganisms, and acetate was supplied as the only exogenous substrate. Addition of more than 10{sup {minus}5} M Np did not inhibit methane production. Total Np volubility in the active microcosm, as well as in sterilized control samples, decreased by nearly two orders of magnitude. A combination of analytical techniques, including VIS-NIR absorption spectroscopy and XANES, identified Np(IV) as the oxidation state associated with the sediments. The similar results from the active microcosm and the abiotic controls suggest that microbian y produced Mn(II/HI) and Fe(II) may serve as electron donors for Np reduction.

  10. Phylogenetic Characterization of a Polychlorinated-Dioxin- Dechlorinating Microbial Community by Use of Microcosm Studies

    PubMed Central

    Yoshida, Naoko; Takahashi, Nobutaka; Hiraishi, Akira

    2005-01-01

    Microcosms capable of reductive dechlorination of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were constructed in glass bottles by seeding them with a polluted river sediment and incubating them anaerobically with an organic medium. All of the PCDD/F congeners detected were equally reduced without the accumulation of significant amounts of less-chlorinated congeners as the intermediate or end products. Alternatively, large amounts of catechol and salicylic acid were produced in the upper aqueous phase. Thus, the dechlorination of PCDD/Fs and the oxidative degradation of the dechlorinated products seemed to take place simultaneously in the microcosm. Denaturing gel gradient electrophoresis and clone library analyses of PCR-amplified 16S rRNA genes from the microcosm showed that members of the phyla Firmicutes, Proteobacteria, and Bacteroidetes predominated. A significant number of Chloroflexi clones were also detected. Quantitative real-time PCR with specific primer sets showed that the 16S rRNA genes of a putative dechlorinator, “Dehalococcoides,” and its relatives accounted for 0.1% of the total rRNA gene copies of the microcosm. Most of the clones thus obtained formed a cluster distinct from the typical “Dehalococcoides” group. Quinone profiling indicated that ubiquinones accounted for 18 to 25% of the total quinone content, suggesting the coexistence and activity of ubiquinone-containing aerobic bacteria. These results suggest that the apparent complete dechlorination of PCDD/Fs found in the microcosm was due to a combination of the dechlorinating activity of the “Dehalococcoides”-like organisms and the oxidative degradation of the dechlorinated products by aerobic bacteria with aromatic hydrocarbon dioxygenases. PMID:16085820

  11. Microcosm studies of microbial degradation in a coal tar distillate plume

    NASA Astrophysics Data System (ADS)

    Harrison, I.; Williams, G. M.; Higgo, J. J. W.; Leader, R. U.; Kim, A. W.; Noy, D. J.

    2001-12-01

    Investigation of a groundwater plume containing up to 24 g l -1 phenolic compounds suggested that over a period of nearly 50 years, little degradation had occurred despite the presence of a microbial community and electron acceptors within the core of the plume. In order to study the effect of contaminant concentration on degradation behaviour, laboratory microcosm experiments were performed under aerobic and anaerobic conditions at four different concentrations obtained by diluting contaminated with uncontaminated groundwater. The microcosms contained groundwater with total phenols at ca. 200, 250, 660 and 5000 mg l -1, and aquifer sediment that had been acclimatised within the plume for several months. The microcosms were operated for a period of 390-400 days along with sterile controls to ascertain whether degradation was microbially mediated or abiotic. Under aerobic conditions, degradation only occurred at concentrations up to 660 mg l -1 total phenols. At phenol concentrations below 250 mg l -1, a benzoquinone intermediate, thought to originate from the degradation of 2,5-dimethylphenol, was isolated and identified. This suggested an unusual degradative pathway for this compound; its aerobic degradation more commonly proceeding via catecholic intermediates. Under anaerobic conditions, degradation only occurred in the most dilute microcosm (total phenols 195 mg l -1) with a loss of p-cresol accompanied by a nonstoichiometric decrease in nitrate and sulphate. By inference, iron(III) from the sediment may also have been used as a terminal electron acceptor, in which case the amount of biologically available iron released was calculated as 1.07 mg Fe(III)/g of sediment. The study shows that natural attenuation is likely to be stimulated by dilution of the plume.

  12. 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

  13. Use of Fixed-Film Bioreactors, in Situ Microcosms, and Molecular Biological Analyses to Evaluate Bioremediation of Chlorinated Benzenes By Indigenous Bacteria and a Bioaugmented Dechlorinating Consortium

    NASA Astrophysics Data System (ADS)

    Lorah, M. M.; Teunis, J. A.

    2014-12-01

    Evaluation of bioremediation is complicated by contaminant mixtures, high concentrations, variable site conditions, and multiple possible degradation pathways. In this study, fixed-film bioreactor experiments, in situ microcosms, and microbial analyses were utilized to evaluate both anaerobic and aerobic biodegradation processes for tri- and dichlorobenzene isomers, monochlorobenzene, and benzene in a wetland. Biofilm-based bioreactors provide a robust assessment tool because of their typically high degree of stability, even with major and repeated perturbations. Two bioreactor units seeded with an anaerobic dechlorinating consortium (WBC-2) and one unit seeded only with bacteria indigenous to the site were operated under flow-through conditions to compare biougmentation and natural attenuation. Electron donor levels were varied to fluctuate between anaerobic and aerobic conditions, and inflow concentrations of total chlorobenzenes were transitioned from 1-10 mg/L to 50-100 mg/L. Biodegradation resulted in removal efficiencies of 80 to 99 percent for the different compounds and inflow concentrations. Degradation efficiency in the native bioreactor was not impacted by cycling between anaerobic and aerobic conditions, although removal rates for monochlorobenzene and benzene increased under aerobic conditions. In situ microcosms were incubated below the wetland surface in sets of 3 treatments—unamended, biostimulated (lactate addition), and bioaugmented (WBC-2 and lactate). Additional treatment sets contained 13C-labeled contaminants to monitor for production of 13C-containing carbon dioxide and cellular material. Microcosm results verified that WBC-2 bioaugmentation can enhance biodegradation, with complete mineralization of chlorobenzene and benzene in bioaugmented and native treatments. Microbial analyses using QuantArrayTM for functional and taxonomic genes indicated potential for co-occurrence of anaerobic and aerobic biodegradation. Compared to the unamended

  14. The Use of Microcosms as an Experimental Approach to Understanding Terrestrial Ecosystem Functioning

    NASA Astrophysics Data System (ADS)

    Fraser, L. H.

    1999-01-01

    Since 1986, a series of microcosm experiments has been conducted at the Unit of Comparative Plant Ecology (UCPE) in an attempt to test our understanding of the principles controlling the structure and dynamics of plant communities and ecosystems. In each experiment microcosms have been seeded with a common pool of organisms, and systems have been allowed to assemble under replicated controlled conditions. Experiment variables have included mineral nutrient supply, temperature, moisture supply, soil depth, carbon dioxide concentration, mycorrhizas, rhizobia, herbivores and carnivores. Results from these experiments are presented to illustrate the value of synthesised ecosystems in ecological research.

  15. A bench-scale treatability study for in situ bioremediation of pentachlorophenol and oil in soil

    SciTech Connect

    Anderson, M.J.; Doxtader, K.G.; Johnson, J.A.; Reardon, K.F.; Tessari, J.D.

    1994-12-31

    The objective of this study was to determine the extent to which indigenous microorganisms could be induced to degrade a mixture of pentachlorophenol (PCP) and diesel oil in the subsurface at a wood treatment site. A second, and related objective, was to determine the overall rate of degradation for (1) PCP, and (2) the petroleum hydrocarbons, and which factors could be controlled to enhance these processes. Contaminated soil samples were incubated under both aerobic and anaerobic conditions for periods varying from 0 to 180 days. The effect of nutrient (N, P, S, K, Mg) supplementation on the rate and extent of degradation in both aerobic and anaerobic microcosms were studied. At eleven selected time intervals the chemical concentrations remaining in a set of microcosms (duplicate samples plus a sterile control) were determined by extracting and analyzing the soils. Enumeration of bacteria, actinomycetes and fungi by plate counting were performed to obtain specific growth rate data. Aerobic microbial activity, as measured by CO{sub 2} evolution, was also determined. Kinetic models and constants were determined to predict cleanup times under the given experimental conditions. Power (zero and first order) and hyperbolic (Michaelis-Menten and Monod) kinetic models were evaluated.

  16. Comparative community responses to elevated atmospheric CO{sub 2} in microcosms and intact grassland

    SciTech Connect

    Chiariello, N.R.

    1995-06-01

    Ecosystem responses to elevated CO{sub 2} involve components that are difficult to resolve in spatially varying, intact systems. Depending on their functional similarity to the field, experimental microcosms may provide more uniform, accessible analogues. At Stanford University`s Jasper Ridge Biological Preserve, research on grassland responses to elevated CO{sub 2} combines field studies and microcosm experiments on annual communities established from seed. Parallel measurements from year 3 of CO{sub 2} treatments in the field and year 2 in the microcosms (after self-seeding) provide a test of their functional similarity. In both, nutrient-poor serpentine soils supported high plant density (>10,000 m{sup -2}), diverse phenology, and low aboveground production (100-200 g m{sup -2}). Elevated CO{sub 2} (720 ppm) favored late-flowering, taprooted annuals in both and had little or no effect on early annuals. Exotic species that were rare in field plots were lost from microcosms by year 2. Annual grasses contributed more to production in microcosms than in the field.

  17. Selective Enrichment Yields Robust Ethene-Producing Dechlorinating Cultures from Microcosms Stalled at cis-Dichloroethene

    PubMed Central

    Delgado, Anca G.; Kang, Dae-Wook; Nelson, Katherine G.; Fajardo-Williams, Devyn; Miceli, Joseph F.; Done, Hansa Y.; Popat, Sudeep C.; Krajmalnik-Brown, Rosa

    2014-01-01

    Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 109 Dehalococcoides mccartyi cells mL−1. Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better

  18. Natural and enhanced biodegradation of propylene glycol in airport soil.

    PubMed

    Toscano, Giuseppe; Colarieti, M Letizia; Anton, Attila; Greco, Guido; Biró, Borbála

    2014-01-01

    Aircraft de-icing fluids (ADF) are a source of water and soil pollution in airport sites. Propylene glycol (PG) is a main component in several commercial formulations of ADFs. Even though PG is biodegradable in soil, seasonal overloads may result in occasional groundwater contamination. Feasibility studies for the biostimulation of PG degradation in soil have been carried out in soil slurries, soil microcosms and enrichment cultures with and without the addition of nutrients (N and P sources, oligoelements), alternative electron acceptors (nitrate, oxygen releasing compounds) and adsorbents (activated carbon). Soil samples have been taken from the contaminated area of Gardermoen Airport Oslo. Under aerobic conditions and in the absence of added nutrients, no or scarce biomass growth is observed and PG degradation occurs by maintenance metabolism at constant removal rate by the original population of PG degraders. With the addition of nutrient, biomass exponential growth enhances aerobic PG degradation also at low temperatures (4 ° C) that occur at the high season of snowmelt. Anaerobic PG degradation without added nutrients still proceeds at constant rate (i.e. no biomass growth) and gives rise to reduced fermentation product (propionic acid, reduced Fe and Mn, methane). The addition of nitrate does not promote biomass growth but allows full PG mineralization without reduced by-products. Further exploitation on the field is necessary to fully evaluate the effect of oxygen releasing compounds and adsorbents. PMID:23828729

  19. Sequential anaerobic-aerobic biodegradation of 2,3,7,8-TCDD contaminated soil in the presence of CMC-coated nZVI and surfactant.

    PubMed

    Binh, Nguyen Duy; Imsapsangworn, Chaiyaporn; Kim Oanh, Nguyen Thi; Parkpian, Preeda; Karstensen, Kare; Giao, Pham Huy; DeLaune, Ronald D

    2016-01-01

    Enriched microorganisms in sediment collected from a dioxin-contaminated site in Vietnam (Bien Hoa airbase) were used for examining the effectiveness in biological treatment of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in soil. Four bio-treatments were investigated using a sequential anaerobic (17 weeks) followed by an aerobic (6 weeks) incubation. The maximum removal efficiency was approximately 60% even at an extremely low pH (approx. 3.6) condition. Surfactant Tween-80 was added to enhance the bioavailability of dioxin in two treatments, but it appeared to biostimulate methanogens rather than dechlorinators. As a result, methane production was the highest while the dioxin removal efficiency was the lowest, as compared with the other bio-treatments. Carboxymethylcellulose (CMC) coated on nanoscale zero valent iron (nZVI) surface used in two treatments could prevent the direct contact between bacterial cell surface and nZVI which prevented cell death and lysis, hence enhancing dioxin removal. The presence of CMC--_nZVI in bio-treatments gradually released H2 required for microbiological processes, but the amount used in the experiments were likely too high to maintain optimum H2 levels for biostimulating dechlorinators rather than methanogens. PMID:26179214

  20. Impairment of cellulose- and cellobiose-degrading soil Bacteria by two acidic herbicides.

    PubMed

    Schellenberger, Stefanie; Drake, Harold L; Kolb, Steffen

    2012-02-01

    Herbicides have the potential to impair the metabolism of soil microorganisms. The current study addressed the toxic effect of bentazon and 4-chloro-2-methylphenoxyacetic acid on aerobic and anaerobic Bacteria that are involved in cellulose and cellobiose degradation in an agricultural soil. Aerobic saccharide degradation was reduced at concentrations of herbicides above environmental values. Microbial processes (e.g. fermentations, ferric iron reduction) that were linked to anaerobic cellulose and cellobiose degradation were reduced in the presence of both herbicides at concentrations above and at those that occur in crop field soil. 16S rRNA gene transcript numbers of total Bacteria, and selected bacterial taxa (Clostridia [Group I], Planctomycetaceae, and two uncultivated taxa of Bacteroidetes) decreased more in anoxic than in oxic cellulose-supplemented soil microcosms in the presence of both herbicides. Collectively, the results suggested that the metabolism of anaerobic cellulose-degrading Bacteria was impaired by typical in situ herbicide concentrations, whereas in situ concentrations did not impair metabolism of aerobic cellulose- and cellobiose-degrading soil Bacteria. PMID:22098368

  1. Biotransformation at 10 C of di-n-butyl phthalate in subsurface microcosms

    SciTech Connect

    Chauret, C.; Inniss, W.E.; Mayfield, C.I.

    1996-09-01

    Di-n-butyl phthalate (DBP) was found to be transformed by microorganisms under aerobic and anaerobic conditions at 10 C in microcosms simulating the Canadian Forces Base (CFB) Borden subsurface environment. Biotransformation of DBP was observed under aerobic, nitrate-reducing, Fe(III)-reducing, and sulfate-reducing conditions. The biotransformation of DBP in the microcosms was significantly decrease3d as the redox potential was lowered, especially under sulfate-reducing conditions. However, other factors such as nutrient depletion and buildup of toxic intermediates could have affected the biotransformation rates. The highest DBP biotransformation rate (0.57 {micro}g DBP{center_dot}g sediment{sup {minus}1}{center_dot}day{sup {minus}1}) was under sulfate-reducing conditions. Biotransformation of DBP at 10 C was significantly enhanced by the addition of 10 mM NaNO{sub 3} suggesting that both the addition of nitrate and high redox conditions favor its biotransformation in subsurface environments.

  2. Biotransformation and Degradation of the Insensitive Munitions Compound, 3-Nitro-1,2,4-triazol-5-one, by Soil Bacterial Communities.

    PubMed

    Krzmarzick, Mark J; Khatiwada, Raju; Olivares, Christopher I; Abrell, Leif; Sierra-Alvarez, Reyes; Chorover, Jon; Field, James A

    2015-05-01

    Insensitive munitions (IM) are a new class of explosives that are increasingly being adopted by the military. The ability of soil microbial communities to degrade IMs is relatively unknown. In this study, microbial communities from a wide range of soils were tested in microcosms for their ability to degrade the IM, 3-nitro-1,2,4-triazol-5-one (NTO). All seven soil inocula tested were able to readily reduce NTO to 3-amino-1,2,4-triazol-5-one (ATO) via 3-hydroxyamino-1,2,4-triazol-5-one (HTO), under anaerobic conditions with H2 as an electron donor. Numerous other electron donors were shown to be suitable for NTO-reducing bacteria. The addition of a small amount of yeast extract (10 mg/L) was critical to diminish lag times and increased the biotransformation rate of NTO in nearly all cases indicating yeast extract provided important nutrients for NTO-reducing bacteria. The main biotransformation product, ATO, was degradable only in aerobic conditions, as evidenced by a rise in the inorganic nitrogen species nitrite and nitrate, indicative of nitrogen-mineralization. NTO was nonbiodegradable in aerobic microcosms with all soil inocula. PMID:25839647

  3. Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experiments

    PubMed Central

    Shi, Y.; Zwolinski, M. D.; Schreiber, M. E.; Bahr, J. M.; Sewell, G. W.; Hickey, W. J.

    1999-01-01

    This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate). The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays. Domain probe analysis of the aquifer samples showed that the communities were predominantly Bacteria; Eucarya and Archaea were not detectable. At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% β- and γ-Proteobacteria (B+G), 31 to 35% α-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria. Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF. The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied. The latter result was hypothesized to reflect enrichment of anaerobic protozoa. Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures. For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65% of the Bacteria community was no longer identifiable by the phylum or subclass probes used. The latter result suggested that toluene exposure fostered the proliferation of phylotype(s) that were otherwise minor constituents of the

  4. Short-term emissions of ammonia and carbon dioxide from cattle urine contaminated tropical grassland microcosm.

    PubMed

    Majumdar, Deepanjan; Patel, Manoj; Drabar, Reena; Vyas, Manish

    2006-11-01

    The study was designed to understand the emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) from a single cattle urination event on a tropical grassland and underline the significance of the emissions in the context of huge animal population grazing on large pasture areas in some countries. Emissions of ammonia (NH(3)) and carbon dioxide (CO(2)) were monitored for three weeks from a tropical grassland (dominated by Cynodon dactylon Pers.) microcosm contaminated with cow and buffalo urine. The grassland microcosms were treated with urine (50 and 100 ml of each) only once and irrigated with water once every week. Ammonia was sampled by an automatic sampling system comprising of a vacuum pump, three-way stopcocks and rubber tubing and an impinger containing suitable absorbing solution (H(2)SO(4)), connected to the tubing suitably. The sampled gas, after sucked by the vacuum pump and absorbed in H(2)SO(4), was allowed to enter the closed microcosm again maintaining internal pressure of the microcosm. Carbon dioxide was sampled by absorption in an alkali (NaOH) trap inside the microcosm. Both NH(3) and CO(2) emissions were highly variable temporally and there was no continuous increasing or decreasing emission trend with time. Respectively, 45 and 46% of total NH(3)-N were emitted within first 48 h from 50 and 100 ml cow urine application while the corresponding values for buffalo urine were 34 and 32%. Total NH(3)-N emissions, integrated for sampling days (i.e. 1, 2, 3, 4, 6, 15, 18 and 21st) were 11 and 6% in cow and 8 and 5% in buffalo urine, of the total-N added through 50 and 100 ml urine samples. Carbon dioxide emissions were standardized at 25 degrees C by using a suitable formula which were lower than actual emissions at actual soil temperature (> 25 degrees C). Carbon dioxide emission rates were classified on the basis of soil repiratory classification and classes ranged from moderately low soil activity up to unusually high soil activity, the latter

  5. Arsenic mobilization and immobilization in paddy soils

    NASA Astrophysics Data System (ADS)

    Kappler, A.; Hohmann, C.; Zhu, Y. G.; Morin, G.

    2010-05-01

    Arsenic is oftentimes of geogenic origin and in many cases bound to iron(III) minerals. Iron(III)-reducing bacteria can harvest energy by coupling the oxidation of organic or inorganic electron donors to the reduction of Fe(III). This process leads either to dissolution of Fe(III)-containing minerals and thus to a release of the arsenic into the environment or to secondary Fe-mineral formation and immobilisation of arsenic. Additionally, aerobic and anaerobic iron(II)-oxidizing bacteria have the potential to co-precipitate or sorb arsenic during iron(II) oxidation at neutral pH that is usually followed by iron(III) mineral precipitation. We are currently investigating arsenic immobilization by Fe(III)-reducing bacteria and arsenic co-precipitation and immobilization by anaerobic iron(II)-oxidizing bacteria in batch, microcosm and rice pot experiments. Co-precipitation batch experiments with pure cultures of nitrate-dependent Fe(II)-oxidizing bacteria are used to quantify the amount of arsenic that can be immobilized during microbial iron mineral precipitation, to identify the minerals formed and to analyze the arsenic binding environment in the precipitates. Microcosm and rice pot experiments are set-up with arsenic-contaminated rice paddy soil. The microorganisms (either the native microbial population or the soil amended with the nitrate-dependent iron(II)-oxidizing Acidovorax sp. strain BoFeN1) are stimulated either with iron(II), nitrate, or oxygen. Dissolved and solid-phase arsenic and iron are quantified. Iron and arsenic speciation and redox state in batch and microcosm experiments are determined by LC-ICP-MS and synchrotron-based methods (EXAFS, XANES).

  6. Atmospheric carbonyl sulfide exchange in bog microcosms

    SciTech Connect

    Fried, A.; Klinger, L.F.; Erickson, D.J. III )

    1993-01-22

    Measurements of Carbonyl sulfide (OCS) fluxes were carried out on bog microcosms using chamber sampling and tunable diode laser analysis. Intact bog microcosms (vascular plants, mosses, and peat) removed ambient levels of OCS in the light and dark with rates from [minus]2.4 to [minus]8.1 ng S min[sup [minus]1] m[sup [minus]2]. Peat and peat plus mosses emitted OCS in the light with rates of 17.4 and 10.9 ng S min[sup [minus]1] m[sup [minus]2], respectively. In the dark, the mosses apparently removed OCS at a rate equivalent to the peat emissions. A 3-D numerical tracer model using this data indicated that boreal bog ecosystems remove at most 1% of ambient OCS, not sufficient to account for an observed OCS depletion in boreal air masses. 13 refs., 1 fig., 1 tab.

  7. Anaerobic biotransformation of trichlorofluoroethene in groundwater microcosms

    SciTech Connect

    Vancheeswaran, S.; Semprini, L. . Dept. of Civil, Construction, and Environmental Engineering); Hyman, M.R. . Dept. of Microbiology)

    1999-06-15

    The biological reduction of trichlorofluoroethene (TCFE) was investigated in anaerobic groundwater microcosms. TCFE was reductively dehalogenated by microorganisms to produce three dichlorofluoroethene isomers, with cis-1,2-dichlorofluoroethene (c-DCFE) being the main isomer formed. Further sequential biological transformation of these compounds to mono-chlorofluoroethene isomers was incomplete and occurred at much slower rates. The rates of TCFE reduction were compared to the rates of reduction of two common chlorinated solvents, perchloroethene (PCE) and trichloroethene (TCE), when present at similar concentrations. Aqueous concentrations ranged from 7.0 to 14.0 mg/L for TCFE and from 7.5 to 15.0 mg/L for PCE and TCE. Similar rates of PCE and TCE transformation relative to TCFE were observed in single-compound tests (PCE, TCE, and TCFE in separate microcosms) and when the contaminants were present together as mixtures in the microcosms. The close similarities between the time course and kinetics of TCFE degradation and the degradation of both PCE and TCE, when present at comparable initial concentrations, suggest that TCFE could potentially be used as a benign reactive tracer to measure in-situ rates of PCE and TCE transformation in contaminated environments.

  8. Sequential anaerobic/aerobic biotreatment of bark leachate.

    PubMed

    Frigon, J C; Cimpoia, R; Guiot, S R

    2003-01-01

    Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96-98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols. PMID:14640219

  9. Biotreatment of explosive contaminated soils

    SciTech Connect

    Shen, C.F.; Guiot, S.R.; Manuel, M.F.

    1995-12-31

    The aim of this research was to develop a process which can be employed to remediate 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soils. The TNT and RDX degrading ability of microorganisms in municipal activated sludge and anaerobic sludge was evaluated, along with the toxicity of TNT and RDX to the microorganisms under aerobic and anaerobic conditions. Biotreatment of TNT and RDX contaminated soils was studied in bioslurry reactors. Microcosm tests were also conducted to see if TNT and RDX removal from the slurry reactor is attributed to a mineralization to CO{sub 2}, and to determine the synergetic or antagonistic effct (if any) of TNT and RDX on the mineralization. Both sludge types were found to be rich sources of RDX degrading organisms. The supplement of anaerobic sludge in bioslurry reactor enhances the biodegradation of TNT and RDX, and leads to complete removal of TNT and RDX from the contaminated soil. Bioslurry reactors may be a cost-effective approach to the on-site bioremediation of soils contaminated with high levels of epxlosives.

  10. Evaluation of terrestrial microcosms for assessing the fate and effects of genetically engineered microorganisms on ecological processes

    SciTech Connect

    Fredrickson, J.K.; Bentjen, S.A.; Bolton, H. Jr.; Li, S.W.; Ligotke, M.W.; McFadden, K.M.; Van Voris, P.

    1989-04-01

    This project evaluates and modifies the existing US Environmental Protection Agency's Office of Pesticides and Toxic Substances (EPA/OPTS) terrestrial microcosm test system and test protocols such that they can be used to determine the environmental fate and ecological hazards of genetically engineered microorganisms (GEMs). The intact soil-core microcosm represents terrestrial ecosystems, and when coupled with appropriate test protocols, such microcosms may be appropriate to define and limit risks associated with the intentional release of GEMs. The terrestrial microcosm test system was used to investigate the survival and transport of two model GEMs (Azospirillum lipoferum and Pseudomonas sp. Tn5 mutants) to various trophic levels and niches and through intact soil cores. Subsequent effects on nutrient cycling and displacement of indigenous microorganisms were evaluated. The model organisms were a diazotrophic root-colonizing bacterium (A. lipoferum) and a wheat root growth-inhibiting rhizobacterium (Pseudomonas sp.). The transposable element Tn5 was used as a genetic marker for both microorganisms in two separate experiments. The organisms were subjected to transposon mutagenesis using a broad host-range-mobilizable suicide plasmid. The transposon Tn5 conferred levels of kanamycin resistance up to 500 ..mu..g/ml (Pseudomonas sp.), which allowed for selection of the bacteria from environmental samples. The presence of Tn5 DNA in the genome of the model GEMs also allowed the use of Tn5 gene probes to confirm and enumerate the microorganisms in different samples from the microcosms. Two types of root growth-inhibiting Pseudomonas sp. Tn5 mutants were obtained and used in microcosm studies: those that lacked the ability to inhibit either wheat root growth or the growth of other microorganisms in vitro (tox/sup /minus//) and those which retained these properties (tox/sup +/). 53 refs., 7 figs., 6 tabs.

  11. COMPARISON OF MICROBIAL TROPHIC INTERACTIONS IN AQUATIC MICROCOSMS DESIGNED FOR THE TESTING OF INTRODUCED MICROORGANISMS

    EPA Science Inventory

    Two aquatic microcosms of different complexity were calibrated with a eutrophic lake. he simple microcosm consisted of an intact sediment core with overlying water. he complex microcosm was compartmentalized (phytoplankton tank, grazer tank, and sediment cores) to allow manipulat...

  12. Cometabolic biodegradation of trichloroethylene in microcosms

    USGS Publications Warehouse

    Kane, Allen C.; Wilson, Timothy P.; Fischer, Jeffrey M.

    1997-01-01

    Laboratory microcosms were used to determine the concentrations of oxygen (O2) and methane (CH4) that optimize trichloroethylene (TCE) biodegradation in sediment and ground-water samples from a TCE-contaminated aquifer at Picatinny Arsenal, Morris County, New Jersey. The mechanism for degradation is the cometabolic activity of methanotrophic bacteria. The laboratory data will be used to support a field study designed to demonstrate the effectiveness of combining air sparging with cometabolic degradation of TCE for the purpose of aquifer remediation. Microcosms were constructed in autoclaved 250-mL (milliliter) amber glass bottles with valves for repeated headspace sampling. Equal volumes (25 mL) of sediment and ground water, collected from a depth of 40 feet, were added. TCE was added to attain initial aqueous concentrations equal to the field level of 1,400 mu g/L (micrograms per liter). Nine microcosms were constructed with initial headspace O2 concentrations of 5%, 10%, or 14% and CH4 concentrations of 0.5%, 3%, or 5%, with nitrogen making up the balance. Sterile controls, controls without CH4, and controls without sediment were also constructed. A 4-mL gas sample was removed periodically and TCE, O2 , CH4 , and carbon dioxide (CO2) concentrations were measured by using gas chromatography. As biodegradation proceeded, the decrease in O2, CH4 , and TCE concentrations and the production of CO2 were monitored. An initial acclimation period of at least 100 days was observed in those microcosms in which significant microbial activity occurred, as determined from decreases in O2 and CH4 concentrations and an increase in CO2 content. Degradation of TCE occurred with O2 concentrations of 2.7 to 8.7% and CH4 concentrations of 0.5 to 3.5%. Microcosms that initially contained 10% O2 and 3% CH4 showed the greatest microbial activity and the greatest amount of TCE degradation. The greatest rates of TCE degradation occurred when O2 and CH4 headspace concentrations reached

  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. 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.

  15. 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;…

  16. Jarosite-related chemical processes and water ecotoxicity in simplified anaerobic microcosm wetlands

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Lin, C.; Wu, Y.; Lu, W.; Liu, Y.; Ma, Y.; Chen, A.

    2008-02-01

    Simulation experiments were conducted to examine whether jarosite is decomposed and toxic products are produced under anaerobic microcosm wetland conditions. The results show that jarosite was stable under water inundation in the microcosm wetland for a period of at least 56 days when no organic substance was added. However, jarosite became increasingly unstable with increasing amount of added organic matter. This resulted in entry of ferrous Fe into the soil solutions. Concentration of other heavy metals in the leachates was extremely low except for Mn. This is attributed to the maintenance of a high pH in the microcosm wetlands, which might cause re-precipitation of originally jarosite-borne heavy metals, if any. No acute toxicity was observed for leachate from the control (non organic matter-added treatment). However, leachates from various organic matter-added treatments show varying degrees of toxicity to the test organism and soluble Fe was likely to be the dominant metal of potential toxicity. Atmospheric exposure of leachate led to oxidation of ferrous Fe and precipitation of iron hydroxide, which caused a drop in leachate pH. This, in turn, inhibited further oxidation of ferrous Fe.

  17. Impact of imidacloprid on life-cycle development of Coccinella septempunctata in laboratory microcosms.

    PubMed

    Yu, Caihong; Lin, Ronghua; Fu, Maoran; Zhou, Yanming; Zong, Fulin; Jiang, Hui; Lv, Ning; Piao, Xiuying; Zhang, Jia; Liu, Yongquan; Brock, Theo C M

    2014-12-01

    Long-term effects of a single application of imidacloprid on ladybird beetle, Coccinella septempunctata L., were studied in indoor laboratory microcosms, starting with the 2nd instar larvae of C. septempunctata but covering the full life cycle. The microcosms comprised enclosures containing a pot with soil planted with broad bean plants and black bean aphid, Aphis craccivora Koch, as food. Exposure doses (0.85-13.66g a.i. ha(-1)) in the long-term microcosm experiment were based on a preliminary short-term (72h) toxicity test with 2nd instar larvae. The measurement endpoints used to calculate NOERs (No Observed Effect application Rates) included development time, hatching, pupation, adult emergence, survival and number of eggs produced. Furthermore, for these endpoints ER50 (application rate causing 50 percent effect) and LR50 (application rate causing 50 percent mortality) values were calculated when possible. The single imidacloprid application affected survival (lowest LR50 4.07g a.i. ha(-1); NOER 3.42g a.i. ha(-1)), egg production (ER50 26.63g a.i. ha(-1)) and egg hatching (NOER 6.83g a.i. ha(-1)). Statistically significant treatment-related effects on the whole development duration, pupation and adult emergence could not be demonstrated (NOER≥13.66g a.i. ha(-1)). The lowest L(E)R50 values and NOERs derived from the laboratory microcosm test with C. septempunctata are lower than the reported field application rates of imidacloprid (15-60g a.i. ha(-1)) in cotton cultivation in China, suggesting potential risks to beneficial arthropods. PMID:25240465

  18. A Reproducible Oral Microcosm Biofilm Model for Testing Dental Materials

    PubMed Central

    Rudney, J.D.; Chen, R.; Lenton, P.; Li, J.; Li, Y.; Jones, R.S.; Reilly, C.; Fok, A.S.; Aparicio, C.

    2012-01-01

    Aims Most studies of biofilm effects on dental materials use single-species biofilms, or consortia. Microcosm biofilms grown directly from saliva or plaque are much more diverse, but difficult to characterize. We used the Human Oral Microbial Identification Microarray (HOMIM) to validate a reproducible oral microcosm model. Methods and Results Saliva and dental plaque were collected from adults and children. Hydroxyapatite and dental composite disks were inoculated with either saliva or plaque, and microcosm biofilms were grown in a CDC biofilm reactor. In later experiments, the reactor was pulsed with sucrose. DNA from inoculums and microcosms were analyzed by HOMIM for 272 species. Microcosms included about 60% of species from the original inoculum. Biofilms grown on hydroxyapatite and composites were extremely similar. Sucrose-pulsing decreased diversity and pH, but increased the abundance of Streptococcus and Veilonella. Biofilms from the same donor, grown at different times, clustered together. Conclusions This model produced reproducible microcosm biofilms that were representative of the oral microbiota. Sucrose induced changes associated with dental caries. Significance and Impact of the Study This is the first use of HOMIM to validate an oral microcosm model that can be used to study the effects of complex biofilms on dental materials. PMID:22925110

  19. 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.

  20. No evidence of aquatic priming effects in hyporheic zone microcosms.

    PubMed

    Bengtsson, Mia M; Wagner, Karoline; Burns, Nancy R; Herberg, Erik R; Wanek, Wolfgang; Kaplan, Louis A; Battin, Tom J

    2014-01-01

    The priming effect refers to quantitative changes in microbial decomposition of recalcitrant organic matter upon addition of labile organic matter and is a phenomenon that mainly has been reported and debated in soil science. Recently, priming effects have been indicated in aquatic ecosystems and have received attention due to the potential significance for ecosystem carbon budgets. Headwater stream biofilms, which are important degraders of both allochthonous, presumably recalcitrant, organic matter and labile autochthonous organic matter, may be sites where priming effects are important in aquatic environments. We have experimentally tested for priming effects in stream biofilms within microcosms mimicking the stream hyporheic zone. A (13)C labeled model allochthonous carbon source was used in combination with different carbon sources simulating autochthonous inputs. We did not detect changes in respiration, removal or incorporation of allochthonous organic matter in response to autochthonous treatments, thus not supporting the occurrence of priming effects under the experimental conditions. This study is the first to address priming effects in the hyporheic zone, and one of very few studies quantitatively assessing aquatic priming effects. The results contrast with existing studies, which highlights the need for quantitative approaches to determine the importance of priming effects in aquatic environments. PMID:24898319

  1. Application of microcosmic system for assessment of insecticide effects on biomarker responses in ecologically different earthworm species.

    PubMed

    Velki, Mirna; Hackenberger, Branimir K; Lončarić, Zeljka; Hackenberger, Davorka K

    2014-06-01

    Earthworms from different ecological categories--epigeic Eisenia andrei and Lumbricus rubellus, endogeic Octolasion lacteum and anecic Lumbricus terrestris--were exposed in a microcosmic system to three commonly used insecticides. The effects of the insecticides were evaluated by measuring the following molecular biomarkers-the activities of AChE, CES, CAT, GST and the concentration of GSH. The results showed that environmentally relevant doses of organophosphates dimethoate and pirimiphos-methyl significantly affected the measured biomarkers, whereas pyrethroid deltamethrin did not affect the earthworms at the recommended agricultural dose. Considering the ecological category of earthworms, the results were inhomogeneous and species-specific differences in the biomarker responses were recorded. Since the biomarker responses of the investigated earthworm species were different after exposure to organophosphates in a microcosm compared to the exposure via standardized toxicity tests, two types of species sensitivity should be distinguished-physiological and environmental sensitivity. In addition, the hormetic effect of organophosphates on AChE and CES activities was recorded. The detection of hormesis in a microcosm is of great importance for future environmental research and soil biomonitoring, since in a realistic environment pollutants usually occur at low concentrations that could cause a hormetic effect. The results demonstrate the importance of the application of microcosmic systems in the assessment of the effects of environmental pollutants and the necessity of taking into account the possible differences between physiological and environmental species sensitivity. PMID:24650551

  2. ELUTRIATOR/MICROCOSM SYSTEM PILOT MODEL AND TEST

    EPA Science Inventory

    An effective technique is described for transferring soft benthic sediments with their resident infauna intact into special holding systems (elutriator/microcosms) which permitted the study under controlled conditions of both nutrient exchange from the sediments and the activitie...

  3. Evaluation of simulated acid precipitation effects on forest microcosms. Final report

    SciTech Connect

    Kelly, J.M.; Strickland, R.C.; Weatherford, F.P.; Noggle, J.C.

    1984-04-01

    Microcosms were treated for a 30-month period with simulated precipitation acidified to four pH levels (5.7, 4.5, 4.0, and 3.5) to evaluate the impact of acid precipitation on foliar leaching, plant nutrient content, soil leaching, soil nutrient content, and litter decomposition. Direct effects of acid precipitation on diameter growth, bud break, leaf senescence, chlorophyll content, stomatal size, stomatal density, photosynthesis, respiration, transpiration, and cuticle erosion were evaluated on tulip poplar, white oak, and Virginia pine seedlings growing as mixed stands in the microcosms. None of the plant physiological or morphological parameters evaluated responded in a statistically significant manner as a result of treatment. A significant treatment canopy interaction was observed in the form of a 60 percent increase in calcium input in throughfall in response to the pH 3.5 treatment. Foliar nutrient content did not change in response to treatment nor did field measurements of decomposer activity. Soil analysis indicated a significantly lower concentration of exchangeable calcium and magnesium in the top 3.5 cm of the mineral soil in association with the pH 3.5 treatment. Soil leachate concentrations exhibited significant increases at both the 25 and 50 cm depths. However, at the 100 cm depth no significant response in concentration or elemental loss from the system was observed. Laboratory respiration measurements indicated a small, but statistically significant reduction in decomposer activity in the lower litter (02) horizon. This reduction was masked in the field measurements of decomposer activity due to the relatively small contribution of the 02 to total soil respiration. 38 references, 12 figures, 18 tables.

  4. Management of aerobic vaginitis.

    PubMed

    Tempera, Gianna; Furneri, Pio Maria

    2010-01-01

    Aerobic vaginitis is a new nonclassifiable pathology that is neither specific vaginitis nor bacterial vaginosis. The diversity of this microbiological peculiarity could also explain several therapeutic failures when patients were treated for infections identified as bacterial vaginosis. The diagnosis 'aerobic vaginitis' is essentially based on microscopic examinations using a phase-contrast microscope (at ×400 magnification). The therapeutic choice for 'aerobic vaginitis' should take into consideration an antibiotic characterized by an intrinsic activity against the majority of bacteria of fecal origin, bactericidal effect and poor/absent interference with the vaginal microbiota. Regarding the therapy for aerobic vaginitis when antimicrobial agents are prescribed, not only the antimicrobial spectrum but also the presumed ecological disturbance on the anaerobic and aerobic vaginal and rectal microbiota should be taken into a consideration. Because of their very low impact on the vaginal microbiota, kanamycin or quinolones are to be considered a good choice for therapy. PMID:21051843

  5. The Effects of Individual PCB Congeners on the Soil Bacterial Community Structure and the Abundance of Biphenyl Dioxygenase Genes

    PubMed Central

    Correa, Paola A.; Lin, LianShin; Just, Craig L.; Hu, Dingfei; Hornbuckle, Keri C.; Schnoor, Jerald L.; Van Aken, Benoit

    2009-01-01

    Polychlorinated biphenyls (PCBs) are toxic environmental contaminants that represent a class of 209 congeners characterized by different degree of chlorination and substitution patterns. Most of experimental studies about microbial degradation of PCBs have been conducted on PCB mixtures, even though evidence accumulated in bacteria and other organisms shows that exposure to different congeners may have different biological effects. Microcosm experiments were conducted using aerobic agitated soil slurries individually exposed to PCB congeners with different degrees of chlorination: PCB-3, 15, 28, and 77, and the commercial mixture Aroclor 1242. After four weeks of incubation, PCBs were analyzed by gas chromatography/mass spectrometry (GC/MS) showing different transformation extents: With the exception of PCB-15 that was not significantly transformed (7%), biodegradation rates decreased with the degree of chlorination, from 75% for PCB-3 to 22% for PCB-77 and Aroclor 1242. The bacterial abundance, as measured by colony counting and 16S rDNA quantification by real-time PCR, was lower (of about 40%) in soil microcosms exposed to the higher-chlorinated congeners, PCB-28, PCB-77, and Aroclor 1242, as compared to non-exposed soils and soils exposed to the lower-chlorinated congeners, PCB-3 and PCB-15. The relative abundance of different taxonomic groups, as determined by real-time PCR, revealed an increase of β-Proteobacteria and Actinobacteria in all microcosms exposed to PCBs, as compared with non-exposed soil. In addition, exposure to PCB-77 and Aroclor 1242 resulted in a higher abundance of α-Proteobacteria and Acidobacteria. Globally, these results suggest that exposure to PCBs (and especially to higher-chlorinated congeners and Aroclor 1242) selected bacterial groups involving most known PCB degraders, i.e., β-Proteobacteria and Acidobacteria. The quantification of biphenyl dioxygenase (BPH) genes - involved in the aerobic degradation of PCBs - using real

  6. Factors Influencing TCE Anaerobic Dechlorination Investigated via Simulations of Microcosm Experiments

    NASA Astrophysics Data System (ADS)

    Mao, X.; Harkness, M.; Lee, M. D.; Mack, E. E.; Dworatzek, S.; Acheson, C.; McCarty, P.; Barry, D. A.; Gerhard, J. I.

    2006-12-01

    SABRE (Source Area BioREmediation) is a public-private consortium whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research project is a field site in the United Kingdom containing a TCE DNAPL source area. In preparation, a microcosm study was performed to determine the optimal combination of factors to support reductive dechlorination of TCE in site soil and groundwater. The study consisted of 168 bottles distributed between four laboratories (Dupont, GE, SiREM, and Terra Systems) and tested the impact of six carbon substrates (lactate, acetate, methanol, SRS (soybean oil), hexanol, butyl acetate), bioaugmentation with KB-1 bacterial culture, three TCE levels (100 mg/L, 400 mg/L, and 800 mg/L) and two sulphate levels (200 mg/L, >500 mg/L) on TCE dechlorination. This research presents a numerical model designed to simulate the main processes occurring in the microcosms, including substrate fermentation, sequential dechlorination, toxic inhibition, and the influence of sulphate concentration. In calibrating the model to over 60 of the microcosm experiments, lumped parameters were employed to quantify the effect of key factors on the conversion rate of each chlorinated ethene in the TCE degradation sequence. Results quantify the benefit (i.e., increased stepwise dechlorination rate) due to both bioaugmentation and the presence of higher sulphate concentrations. Competitive inhibition is found to increase in significance as TCE concentrations increase; however, inclusion of Haldane inhibition is not supported. Over a wide range of experimental conditions and dechlorination steps, SRS appears to induce relatively little hydrogen limitation, thereby facilitating relatively quick conversion of TCE to ethene. In general, hydrogen limitation is found to increase with increasing TCE concentration and with bioaugmentation, and

  7. Teaching Aerobic Lifestyles: New Perspectives.

    ERIC Educational Resources Information Center

    Goodrick, G. Ken; Iammarino, Nicholas K.

    1982-01-01

    New approaches to teaching aerobic life-styles in secondary schools are suggested, focusing on three components: (1) the psychological benefits of aerobic activity; (2) alternative aerobic programs at nonschool locations; and (3) the development of an aerobics curriculum to help maintain an active life-style after graduation. (JN)

  8. MICROCOSM METHOD TO ASSESS SURVIVAL OF RECOMBINANT BACTERIA ASSOCIATED WITH PLANTS AND HERBIVOROUS INSECTS (JOURNAL VERSION)

    EPA Science Inventory

    A microcosm method was developed to investigate survival and fate of genetically engineered bacteria associated with plant surfaces and a plant-feeding insect, the variegated cutworm, Peridroma saucia. Larvae on radish plants in microcosms were sprayed with nonrecombinant Pseudom...

  9. 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)

  10. 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

  11. Persistence of microbial and chemical pig manure markers as compared to faecal indicator bacteria survival in freshwater and seawater microcosms.

    PubMed

    Solecki, O; Jeanneau, L; Jardé, E; Gourmelon, M; Marin, C; Pourcher, A M

    2011-10-01

    Natural seawater and freshwater microcosms inoculated with pig manure were set up to determine the persistence of pig faecal microbial and chemical markers in these two types of surface water. The concentrations of Lactobacillus amylovorus, the Bacteroidales Pig-2-Bac 16S rRNA genetic marker, five stanols and the evolution of two ratios of stanols, R1 (coprostanol to the sum of coprostanol and 24-ethylcoprostanol) and R2 (sitostanol to coprostanol) were analyzed during two months along with the concentration of Faecal Indicator Bacteria (FIB). Pig manure was inoculated to unfiltered water microcosms incubated aerobically at 18 °C in the dark. The faecal contamination load represented by the concentrations of culturable Escherichia coli and/or enterococci remained for two months in the freshwater and seawater microcosms water column. These concentrations followed a biphasic decay pattern with a 97% reduction of the initial amount during a first rapid phase (<6 days) and a remaining proportion undergoing a slower or null second decline. The L. amylovorus marker and five stanols persisted as long as the indicators in both treatments. The Pig-2-Bac marker persisted 20 and 27 days in seawater and freshwater, respectively. The ratios R1 and R2 were in the range specific to pig manure until day 6 in both types of water. These results indicate that Pig-2-Bac, L. amylovorus and stanol ratios might be used in combination to complement FIB testing to determine the pig source of fecal pollution. However, stanol ratios are to be used when the time point of the discharge is known. PMID:21745675

  12. Aerobic decomposition of crop residues improves N availability and grain yield for three rice soils of the Mekong Delta, Vietnam: A screenhouse study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Mekong Delta of Vietnam, rice (Oryza sativa, L.) is usually planted two to three times annually. Limited evidence elsewhere suggests that rice crop uptake of soil nitrogen (N) under such intensive cropping can be increased by replacing the customary anaerobic decomposition of crop residues wi...

  13. IMPACT OF UV-B RADIATION UPON ESTUARINE MICROCOSMS

    EPA Science Inventory

    Twelve flow-through estuarine microcosms were exposed daily to four different levels of UV-B radiation. In addition to a natural level of visible solar radiation. The parameters studied over a four week period were phytoplankton community composition, plankton biomass (ash-free d...

  14. Comparison of laboratory batch and flow-through microcosm bioassays.

    PubMed

    Clément, Bernard J P; Delhaye, Hélène L; Triffault-Bouchet, Gaëlle G

    2014-10-01

    Since 1997, we have been developing a protocol for ecotoxicological bioassays in 2-L laboratory microcosms and have applied it to the study of various pollutants and ecotoxicological risk assessment scenarios in the area of urban facilities and transport infrastructures. The effects on five different organisms (micro-algae, duckweeds, daphnids, amphipods, chironomids) are assessed using biological responses such as growth, emergence (chironomids), reproduction (daphnids) and survival, with a duration of exposure of 3 weeks. This bioassay has mainly been used as a batch bioassay, i.e., the water was not renewed during the test. A flow-through microcosm bioassay has been developed recently, with the assumption that conditions for the biota should be improved, variability reduced, and the range of exposure patterns enlarged (e.g., the possibility of maintaining constant exposure in the water column). This paper compares the results obtained in batch and flow-through microcosm bioassays, using cadmium as a model toxicant. As expected, the stabilization of physico-chemical parameters, increased organism fitness and reduced variability were observed in the flow-through microcosm bioassay. PMID:25086825

  15. Figs and fig wasps: evolution in a microcosm.

    PubMed

    Cook, J M; Lopez-Vaamonde, C

    2001-06-01

    Fig wasps are tiny insects that both pollinate and feed upon fig plants. Each species requires the other in order to complete its reproductive cycle. The interaction centres on the unique structure of syconium (fig inflorescence), which provides an intriguing and convenient microcosm for studying the action of both natural and sexual selection. PMID:11399840

  16. CHARACTERIZING THE MICROBIAL COMMUNITY IN SABRE MICROCOSM STUDIES (ABSTRACT ONLY)

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, laboratory microcosm and column studies were conducte...

  17. FATE OF SELECTED HERBICIDES IN A TERRESTRIAL LABORATORY MICROCOSM

    EPA Science Inventory

    The transport and metabolism of 14C-labeled herbicides (simazine, bromacil, trifluralin, and 2,4,5-T) applied as a foliar spray (0.28 kg/ha) was examined in a terrestrial microcosm chamber (TMC). These chemicals were compared to a reference compound, the insecticide dieldrin. The...

  18. METRICS OF PERFORMANCE FOR THE SABRE MICROCOSM STUDY (ABSTRACT ONLY)

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project will evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In preparation for a field scale pilot test, a laboratory microcosm study was conducted to provide...

  19. TROPHIC STRUCTURE MODIFICATIONS BY PLANKTIVOROUS FISH IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Two of 4 replicate 700-liter aquatic microcosms each were stocked with 2 mosquito fish (Gambusia affinis). The dominant zooplankter shifted from the large cladoceran Simocephalus vetulus to the smaller Alona guttata. The subsequent release of grazing pressure resulted in a rise i...

  20. Degradation and bioavailability of sulfamethazine in pond water microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to farm ponds. We investigated the degradation and fate of sulfamethazine in small pond water microcosms. 14C-phenyl-sulfamethazine was added to the pond water column in a swine manure slurry or in water. Residual concentrations in...

  1. FATE AND IMPACT OF WOOD PRESERVATIVES IN A TERRESTRIAL MICROCOSM

    EPA Science Inventory

    The transport and effects of 14C-labeled wood preservatives (creosote with labeled phenanthrene or acenaphthene, pentachlorophenol, and bis(tri-n-butyltin)oxide) impregnated in wood posts were examined in a terrestrial microcosm chamber (TMC-II) in comparison to a reference compo...

  2. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  3. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  4. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  5. Managing for Improved Aerobic Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic deterioration or spoilage of silage is the result of aerobic microorganisms metabolizing components of the silage using oxygen. In the almost 40 years over which these silage conferences have been held, we have come to recognize the typical pattern of aerobic microbial development by which s...

  6. Modelling of Genetically Engineered Microorganisms Introduction in Closed Artificial Microcosms

    NASA Astrophysics Data System (ADS)

    Pechurkin, N. S.; Brilkov, A. V.; Ganusov, V. V.; Kargatova, T. V.; Maksimova, E. E.; Popova, L. Yu.

    1999-01-01

    The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E.coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.

  7. Transformation of triclosan and triclocarban in soils and biosolids-applied soils.

    PubMed

    Kwon, Jeong-Wook; Armbrust, Kevin L; Xia, Kang

    2010-01-01

    Triclosan (TCS) and triclocarban (TCC), widely used as antibacterial agents, have been frequently detected in biosolids. Biosolids land application may introduce pharmaceuticals and personal care products (PPCPs) such as TCS and TCC into the environment. Microcosm studies were conducted to investigate TCS and TCC transformation in Marietta fine loam and McLaurin coarse loam. Both compounds were spiked into the soils with and without biosolids amendment under non-sterilized and sterilized conditions and incubated aerobically at 30 degrees C for up to 100 d. In both soils, transformation of TCS followed second-order reaction kinetics, with estimated reaction rate constants of (5.27 +/- 0.920) x 10(-1) and (9.13 +/- 1.58) x 10(-2) (mg kg(-1))(-1) d(-1) for Marietta fine loam and McLaurin coarse loam, respectively. Transformation of TCC in both soils was slower than that for TCS. After 100 d, 53 +/- 1% and 71 +/- 2% of the initially added TCC and only 2.8 +/- 0.35% and 6.2 +/- 0.80% of initially added TCS remained in Marietta fine loam and McLaurin coarse loam, respectively. The transformation of both compounds were faster in the Marietta fine loam (pH 7.8; 1.8% organic matter) than in the McLaurin coarse loam (pH 4.7; 0.65% organic matter). Our result suggests that biotic processes are more of a controlling factor affecting TCS transformation, whereas abiotic processes may affect TCC transformation more significantly. Addition of biosolids to the two soils slowed the transformation of both compounds, indicating interactions between both compounds and biosolids may adversely affect their transformation in soils, an important factor that must be included in models predicting environmental fate of biosolids-associated PPCPs. PMID:20830900

  8. Microbial community characterization and functional gene quantification in RDX-degrading microcosms derived from sediment and groundwater at two naval sites.

    PubMed

    Wilson, Fernanda Paes; Cupples, Alison M

    2016-08-01

    The explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has long been recognized as a problematic environmental pollutant, and efforts to remediate contaminated soils, sediments, and groundwater have been going on for decades. In recent years, much interest has focused on using bioremediation to clean up these sites. The current study investigated the microorganisms (16S rRNA genes, Illumina) and functional genes (xenA, xenB, and xplA) linked to RDX biodegradation in microcosms composed of sediment or groundwater from two Navy sites. For this, experiments included sediment samples from three depths (5 to 30 ft) from two wells located in one Navy site. In addition, the groundwater upstream and downstream of an emulsified oil biobarrier was examined from another Navy site. Further, for the groundwater experiments, the effect of glucose addition was explored. For the sediment experiments, the most enriched phylotypes during RDX degradation varied over time, by depth and well locations. However, several trends were noted, including the enrichment of Pseudomonas, Rhodococcus, Arthrobacter, and Sporolactobacillus in the sediment microcosms. For the groundwater-based experiments, Pseudomonas, unclassified Rhodocyclaceae, Sphingomonas, and Rhodococcus were also highly abundant during RDX degradation. The abundance of both xplA and xenA significantly increased during RDX degradation compared to the control microcosms for many treatments (both groundwater and sediment microcosms). In a limited number of microcosms, the copy number of the xenB gene increased. Phylotype data were correlated with functional gene data to highlight potentially important biomarkers for RDX biodegradation at these two Navy sites. PMID:27118012

  9. Survival and Phospholipid Fatty Acid Profiles of Surface and Subsurface Bacteria in Natural Sediment Microcosms

    PubMed Central

    Kieft, T. L.; Wilch, E.; O'Connor, K.; Ringelberg, D. B.; White, D. C.

    1997-01-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P. fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. PMID:16535578

  10. Survival and phospholipid fatty acid profiles of surface and subsurface bacteria in natural sediment microcosms

    SciTech Connect

    Kieft, T.L.; Wilch, E.; O`Connor, K.

    1997-04-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P.fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. 40 refs., 7 figs.

  11. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  12. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  13. Kinetics of di-(2-ethylhexyl)phthalate mineralization in sludge-amended soil

    SciTech Connect

    Madsen, P.L.; Thyme, J.B.; Henriksen, K.; Moeldrup, P.; Roslev, P. . Environmental Engineering Lab.)

    1999-08-01

    Sewage sludge is frequently used as a soil fertilizer although it may contain elevated concentrations of priority pollutants including di-(2-ethylhexyl)phthalate (DEHP). In the present study, the kinetics of microbial [[sup 14]C]DEHP mineralization was studied in laboratory microcosms with sewage sludge and agricultural soil. A biphasic model with two independent kinetic expressions was used to fit the mineralization data. The initial mineralization activity was described well by first-order kinetics, whereas mineralization in long-term incubations was described better by fractional power kinetics. The mineralization activity was much lower in the late phase presumably due to a decline in the bioavailability of DEHP caused by diffusion-limited desorption. The initial DEHP mineralization rate in sludge-amended soil varied between 3.7 and 20.3 ng of DEHP (g dw)[sup [minus]1]d[sup [minus]1] depending on incubation conditions. Aerobic DEHP mineralization was 4--5 times faster than anaerobic mineralization, DEHP mineralization in sludge-amended soil was much more temperature sensitive than was DEHP mineralization in soil without sludge. Indigenous microorganisms in the sewage sludge appeared to dominate DEHP degradation in sludge-amended soil. It was estimated that > 41% of the DEHP in sludge-amended soil will have escaped mineralization after 1 year. In the absence of oxygen, > 68% of the DEHP will not be mineralized within 1 year. Collectively, the data suggest that a significant fraction of the DEHP in sludge-amended soils may escape mineralization under in situ conditions.

  14. Biodegradation of phenols in a sandstone aquifer under aerobic conditions and mixed nitrate and iron reducing conditions

    NASA Astrophysics Data System (ADS)

    Broholm, Mette M.; Arvin, Erik

    2000-08-01

    Ammonia liquor with very high concentrations of phenol and alkylated phenols is known to have leaked into the subsurface at a former coal carbonization plant in the UK, giving high concentrations of ammonium in the groundwater. In spite of this, no significant concentrations of phenols were found in the groundwater. The potential for biodegradation of the phenols in the sandstone aquifer at the site has been investigated in laboratory microcosms under aerobic (oxygen amended) and mixed nitrate and iron reducing (nitrate enriched and unamended) anaerobic conditions, at a range of concentrations (low: ˜5 mg l -1, high: ˜60 mg l -1, and very high: ˜600 mg l -1) and in the presence of other organic coal-tar compounds (mono- and polyaromatic hydrocarbons (BTEXs and PAHs) and heterocyclic compounds (NSOs)) and ammonia liquor. Sandstone cores and groundwater for the microcosms were collected from within the anaerobic ammonium plume at the field site. Fast and complete degradation of phenol, o- and p-cresol, 2,5- and 3,4-xylenol with no or very short initial lag-phases was observed under aerobic conditions at low concentrations. 2,6- and 3,5-Xylenol were degraded more slowly and 3,5-xylenol degradation was only just complete after about 1 year. The maximum rates of total phenols degradation in duplicate aerobic microcosms were 1.06 and 1.76 mg l -1 day -1. The degradation of phenols in nitrate enriched and unamended anaerobic microcosms was similar. Fast and complete biodegradation of phenol, cresols, 3,4-xylenol and 3,5-xylenol was observed after short lag-phases in the anaerobic microcosms. 2,5-xylenol was partially degraded after a longer lag-phase and 2,6-xylenol persisted throughout the 3 month long experiments. The maximum rates of total phenols degradation in duplicate nitrate enriched and unamended anaerobic microcosms were 0.30-0.38 and 0.29-0.31 mg l -1 day -1, respectively. The highest phenols concentrations in the anaerobic microcosms apparently required

  15. EFFECTS OF SEDIMENT TYPE ON BENTHIC MACROINFAUNAL COLONIZATION OF LABORATORY MICROCOSMS

    EPA Science Inventory

    We tested the effects of four different sediment types on macroinfaunal colonization and community development in our laboratory flow-thru microcosm system (all microcosms were 20 cm side-1 and sediment depth was 5 cm) over a period of 41 days. Sediments included Santa Rosa Islan...

  16. ASSESSMENT OF THE PRECISION AND ACCURACY OF SAM AND MFC MICROCOSMS EXPOSED TO TOXICANTS

    EPA Science Inventory

    The results of 30 mixed flank culture (MFC) and four standardized aquatic microcosm (SAM) microcosm experiments were used to describe the precision and accuracy of these two protocols. oefficients of variation (CV) for chemicals measurements (DO,pH) were generally less than 7%, f...

  17. FATE OF FENTHION IN SALT-MARSH ENVIRONMENTS: II. TRANSPORT AND BIODEGRADATION IN MICROCOSMS

    EPA Science Inventory

    The fate of fenthion was examined in microcosms to define the possible interaction between sediment and biodegradation in the field. athematical model was also calibrated to calculate the distribution of fenithion in microcosms. ntact sediment cores, both with and without Juncus ...

  18. Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

    PubMed Central

    Krause, Stefan

    2016-01-01

    While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

  19. Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

    PubMed

    Baranov, Viktor; Lewandowski, Jörg; Krause, Stefan

    2016-08-01

    While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m(2) was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

  20. Extracellular proteases are released by ciliates in defined seawater microcosms.

    PubMed

    Thao, Ngo Vy; Nozawa, Akino; Obayashi, Yumiko; Kitamura, Shin-Ichi; Yokokawa, Taichi; Suzuki, Satoru

    2015-08-01

    The biodegradation of proteins in seawater requires various proteases which are commonly thought to be mainly derived from heterotrophic bacteria. We, however, found that protists showed a high protease activity and continuously produced trypsin-type enzymes. The free-living marine heterotrophic ciliate Paranophrys marina together with an associated bacterium was isolated and used for microcosm incubation with different concentrations of killed bacteria as food for 10 days. The results showed that the co-existence of the ciliate with its associated bacterium produced a significant protease activity in both cell-associated and cell-free fractions while that in the associated bacterium only microcosm was negligible. The protease profiles are different between cell-associated and cell-free fractions, and a trypsin-type enzyme hydrolyzing Boc-Val-Leu-Lys-MCA was detected throughout the period in the presence of ciliates. This suggests that ciliates release proteases into the surrounding environment which could play a role in protein digestion outside cells. It has been previously suggested that bacteria are the major transformers in seawater. We here present additional data which indicates that protists, or at least ciliates with their specific enzymes, are a potential player in organic matter degradation in water columns. PMID:26115436

  1. Azolla-anabaena-bacteria system as a natural microcosm

    NASA Astrophysics Data System (ADS)

    Carrapico, Francisco J.

    2002-02-01

    Azolla is an aquatic fern that contains a permanent endosymbiotic prokaryotic community (cyanobacteria and bacteria) inside of the cavity in the leaf dorsal lobe of the pteridophyte. This is a unique situation and can be seen as a microcosm inside of an organism and also can be considered a good example of a living model for biological and environmental studies. These symbionts are specific of this symbiosis and lives immobilized in a mucilaginous fibrillar network, which fills part of the cavity. The symbionts works as immobilized organisms in a natural system that can be used as a model for biotechnological research and in biologically based life support systems. The nature and the complexity of this system is simultaneously a reference and a challenge for the research in the communication between the two levels of nature organization (microcosm and mesocosm), and can also be used as a reference for the design of new environmental engineered symbiotic systems that include man as a prelude to life in space.

  2. Microcosm experiments of oil degradation by microbial mats.

    PubMed

    de Oteyza, Tirso García; Grimalt, Joan O; Llirós, Marc; Esteve, Isabel

    2006-03-15

    Several microcosm experiments were run in parallel to evaluate the efficiency of microbial mats for crude oil degradation as compared with physico-chemical weathering. The oils used in the experiments constituted representative examples of those currently used for commercial purposes. One was aliphatic and of low viscosity (33.4 American Petroleum Institute degrees, degrees API) and the other was predominantly aromatic, with high sulphur content (ca. 2.7%) and viscosity (16.6 degrees API). After crude oil introduction, the microcosms were kept under cyclic changes in water level to mimic coastal tidal movements. The transformations observed showed that water weathering leads to more effective and rapid elimination of low molecular weight hydrocarbons than microbial mat metabolism, e.g. n-alkanes with chain length shorter than n-pentadecane or n-heptadecane, regular isoprenoid hydrocarbons with chain length lower than C16 or C18 or lower molecular weight naphthalenes. Microbial mats preserved these hydrocarbons from volatilization and water washing. However, hydrocarbons of lower volatility such as the C24-C30 n-alkanes or containing nitrogen atoms, e.g. carbazoles, were eliminated in higher proportion by microbial mats than by water weathering. The strong differences in composition between the two oils used for the experiments were also reflected in significant differences between water weathering and microbial mat biodegradation. Higher oil viscosity seemed to hinder the former but not the later. PMID:15935450

  3. Alteration of Rock Fragments from Columbia River Basalt Microcosms

    NASA Technical Reports Server (NTRS)

    Wentworth, Susan J.; Thomas-Keprta, Kathie L.; Velbel, Michael A.; McKay, David S.; Stevens, Todd O.

    1999-01-01

    During an earlier study, microorganisms were grown microcosms consisting of sterilized chips of Columbia River Basalt (CRB) and natural CRB ground water with its natural microflora; environmental conditions simulated a deep subsurface, anaerobic, dark environment. Subsequent scanning and transmission electron microscope (SEM and TEM) studies revealed the presence of several types of bacteria and biofilm, some of which were mineralized. Some of these biological features are very similar to possible biogenic features found in two meteorites from Mars, ALH84001 (found in Antarctica) and Nakhla (observed to fall in Egypt). Both ALH84001 and Nakhla contain traces of low-temperature aqueous alteration of silicates, oxides, and sulfides. The goals of this study are to use high-resolution field-emission SEM (FE-SEM) to examine the CRB samples for evidence of alteration features similar to those in the martian meteorites, to determine the extent of alteration during the CRB microcosm experiments, and to determine whether effects of biological activity can be distinguished from inorganic effects.

  4. Ecological changes in oral microcosm biofilm during maturation.

    PubMed

    Kim, Young-Seok; Kang, Si-Mook; Lee, Eun-Song; Lee, Ji Hyun; Kim, Bo-Ra; Kim, Baek-Il

    2016-10-01

    The aim of this study was to evaluate the ecological changes in the biofilm at different stages of maturation using 16S rDNA gene amplicon sequencing and to identify correlations between red/green (R/G) fluorescence ratio and ecological changes. An oral microcosm biofilm was initiated from the saliva of a single donor and grown anaerobically for up to 10 days in basal medium mucin. Quantitative light-induced fluorescence analysis was shown that the R/G ratio of the biofilm increased consistently, but the slope rapidly decreased after six days. The bacterial compositions of 10 species also consistently changed over time. However, there was no significant correlation between each bacteria and red fluorescence. The monitoring of the maturation process of oral microcosm biofilm over 10 days revealed that the R/G ratio and the bacterial composition within biofilm consistently changed. Therefore, the R/G fluorescence ratio of biofilm may be related with its ecological change rather than specific bacteria PMID:26950795

  5. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1997-01-01

    Provides school counselors with information on aerobic exercise (specifically running) and the psychological, behavioral, and physical benefits children obtained by participating in fitness programs. Recommends collaboration between school counselors and physical education teachers and gives a preliminary discussion of aerobic running and its…

  6. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1992-01-01

    Provides school counselors with information regarding aerobic exercise (specifically running), and the psychological, behavioral, and physical benefits children obtain by participating in fitness programs. Presents methods of collaboration between school counselors and physical education teachers. Offers preliminary discussion of aerobic running…

  7. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  8. Use of in situ microcosms for evaluating reservoir water management options

    SciTech Connect

    French, R.H. ); Cooper, J.J. ); Vigg, S. )

    1988-10-01

    The use of in situ microcosms for performing reservoir trophic studies and aiding in the design of reservoir restoration programs are discussed. The site of this study was Lahontan Reservoir, Nevada, which has experienced water quality problems associated with monospecific blooms of blue-green algae and hypolimnetic dissolved oxygen depletions. In situ microcosms were used to investigate the response of phytoplankton species composition to additions of the nutrients nitrogen, phosphorus, and the phosphorus precipitant aluminum sulfate. At the end of the 16-day experimental period, the microcosms receiving the phosphate treatments yielded the highest standing crops of algae and the greatest percentage composition of blue-green algae. The microcosms receiving the nitrate treatment exhibited greater initial algal concentrations followed by a decline in phytoplankton, which coincided with an increase in the zoo-plankton population. The results presented here suggest that microcosms can be a cost-effective method for assessing reservoir water quality and planning restoration programs.

  9. Aerobic and Anaerobic Respiration in Profiles of Polesie Lubelskie Peatlands

    NASA Astrophysics Data System (ADS)

    Szafranek-Nakonieczna, Anna; Stêpniewska, Zofia

    2014-04-01

    Soil respiration is a very important factor influencing carbon deposition in peat and reflecting the intensity of soil organic matter decomposition, root respiration, and the ease of transporting gases to the surface. Carbon dioxide release from three different peat soil profiles (0-80 cm) of the Polesie Lubelskie Region (Eastern Poland) was analyzed under laboratory conditions. Peat samples were incubated at 5, 10, and 20°C in aerobic and anaerobic environments, and their CO2-evolution was analyzed up to 14 days. The respiration activity was found to be in the range of 0.013-0.497 g CO2 kg-1 DW d-1. The respiratory quotient was estimated to be in the range of 0.51-1.51, and the difference in respiration rates over 10°C ranged between 4.15 and 8.72 in aerobic and from 1.15 to 6.53 in anaerobic conditions. A strong influence of temperature, depth, the degree of peat decomposition, pH, and nitrate content on respiration activity was found. Lack of oxygen at low temperature caused higher respiration activity than under aerobic conditions. These results should be taken into account when the management of Polish peatlands is considered in the context of climate and carbon storage, and physicochemical properties of soil in relation to soil respiration activity are considered.

  10. Planetary Bioresources and Astroecology. 1. Planetary Microcosm Bioassays of Martian and Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, and Algal and Plant Responses

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    2002-07-01

    The biological fertilities of planetary materials can be assessed using microcosms based on meteorites. This study applies microcosm tests to martian meteorites and analogues and to carbonaceous chondrites. The biological fertilities of these materials are rated based on the soluble electrolyte nutrients, the growth of mesophile and cold-tolerant algae, and plant tissue cultures. The results show that the meteorites, in particular the Murchison CM2 carbonaceous chondrite and DaG 476 martian shergottite, contain high levels of water-extractable Ca, Mg, and SO 4-S. The martian meteorites DaG 476 and EETA 79001 also contain higher levels of extractable essential nutrients NO 3-N (0.013-0.017 g kg -1) and PO 4-P (0.019-0.046 g kg -1) than the terrestrial analogues. The yields of most of the water-extractable electrolytes vary only by factors of 2-3 under a wide range of planetary conditions. However, the long-term extractable phosphate increases significantly under a CO 2 atmosphere. The biological yields of algae and plant tissue cultures correlate with extractable NO 3-N and PO 4-P, identifying these as the limiting nutrients. Mesophilic algae and Asparagus officinalis cultures are identified as useful bioassay agents. A fertility rating system based on microcosm tests is proposed. The results rate the fertilities in the order martian basalts > terrestrial basalt, agricultural soil > carbonaceous chondrites, lava ash > cumulate igneous rock. The results demonstrate the application of planetary microcosms in experimental astroecology to rate planetary materials as targets for astrobiology exploration and as potential space bioresources. For example, the extractable materials in Murchison suggest that concentrated internal solutions in carbonaceous asteroids (3.8 mol L -1 electrolytes and 10 g L -1 organics) can support and disperse microorganisms introduced by natural or directed panspermia in early solar systems. The results also suggest that carbonaceous asteroids

  11. Temporal variation of magnetotactic bacterial communities in two freshwater sediment microcosms.

    PubMed

    Lin, Wei; Pan, Yongxin

    2010-01-01

    Magnetotactic bacteria (MTB), which can mineralize nanosized magnetite or greigite crystals within cells, play important roles in biogeochemical processes, for example iron and sulfur cycling, and depositional remanent magnetization acquisitions. Despite decades of research, the knowledge of MTB distribution and ecology is still limited. In the present study, we investigated the temporal variation of MTB communities in freshwater sediment microcosms based on 16S rRNA genes and unifrac analyses. Two microcosms (MY8 and MY11) collected from two separate sites in Lake Miyun (Beijing, China) were analyzed. The majority of retrieved sequences belonged to alphaproteobacterial magnetotactic cocci in both microcosms (representing 64.29% of clones from MY8 and 100% of clones from MY11), whereas so-called 'Magnetobacterium bavaricum'-like MTB affiliated within Nitrospira phylum were exclusively found in microcosm MY8. Over a 3-month period, the temporal variation of MTB communities was evident in both microcosms. In addition, the phylogenetic discrepancy of MTB communities between two microcosms is more prominent than that of the same microcosm at different times, implying adaptation of MTB phylogenetic lineages to specific microenvironments. Among the physical-chemical parameters measured, a strong correlation was shown between nitrate and the main genetic variability of MTB communities, indicating that nitrate may influence the occurrence of MTB phylogenetic lineages in natural environments. PMID:19909346

  12. Use of microcosms to determine the survival of the fish pathogen Tenacibaculum maritimum in seawater.

    PubMed

    Avendaño-Herrera, Ruben; Irgang, Rute; Magariños, Beatriz; Romalde, Jesús L; Toranzo, Alicia E

    2006-05-01

    The survival of the fish pathogen Tenacibaculum maritimum in different seawater microcosms was investigated during 160 days. The persistence of culturable cells was greater in sterile than in natural seawater. Standard plate counts showed that T. maritimum survived in sterile seawater for more than 5 months at concentration around 10(3) cfu ml(-1). However, T. maritimum proved to be very labile in non-sterile seawater, rendering culturable cells no longer than 5 days. These results were confirmed when DNA-based methods were applied. Regardless of the microcosms used, epifluorescence microscopy counts remained at about 10(6) cells ml(-1) throughout the experiment, even though we can not distinguish T. maritimum in the case of non-sterile microcosms. Resuscitation assays with addition of fresh medium to non-sterile microcosms did not favour the recovery of T. maritimum on solid media. Although morphological changes from filamentous to spheres were observed after 3 days in the non-sterile microcosms, in the case of the sterile microcosms this change was observed at the sixth day. The biochemical, physiological, serological and genetic characteristics were unaffected in the sterile microcosms. The overall results contribute to a better understanding of the behaviour of T. maritimum in natural seawater and suggest that the aquatic bacterial population play an important role in the survival of this fish pathogen. PMID:16623748

  13. The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil

    SciTech Connect

    Carbonell-Barrachina, A.; Jugsujinda, A.; DeLaune, R.D.; Patrick, W.H. Jr.; Burlo, F.; Sirisukhodom, S.; Anurakpongsatorn, P.

    1999-07-01

    Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic matter and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.

  14. BIODEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM CRUDE OIL IN SANDY-BEACH MICROCOSMS.

    EPA Science Inventory

    Though the lower n-alkanes are considered the most degradable components of crude oil, our experiments with microcosms simulating oiled beaches showed substantial depletion of fluorene, phenanthrene, dibenzothiophene, and other PAH in control treatments consisting of raw seawater...

  15. 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.

  16. Stability and resilience of oral microcosms toward acidification and Candida outgrowth by arginine supplementation.

    PubMed

    Koopman, Jessica E; Röling, Wilfred F M; Buijs, Mark J; Sissons, Christopher H; ten Cate, Jacob M; Keijser, Bart J F; Crielaard, Wim; Zaura, Egija

    2015-02-01

    Dysbiosis induced by low pH in the oral ecosystem can lead to caries, a prevalent bacterial disease in humans. The amino acid arginine is one of the pH-elevating agents in the oral cavity. To obtain insights into the effect of arginine on oral microbial ecology, a multi-plaque "artificial mouth" (MAM) biofilm model was inoculated with saliva from a healthy volunteer and microcosms were grown for 4 weeks with 1.6 % (w/v) arginine supplement (Arginine) or without (Control), samples were taken at several time-points. A cariogenic environment was mimicked by sucrose pulsing. The bacterial composition was determined by 16S rRNA gene amplicon sequencing, the presence and amount of Candida and arginine deiminase system genes arcA and sagP by qPCR. Additionally, ammonium and short-chain fatty acid concentrations were determined. The Arginine microcosms were dominated by Streptococcus, Veillonella, and Neisseria and remained stable in time, while the composition of the Control microcosms diverged significantly in time, partially due to the presence of Megasphaera. The percentage of Candida increased 100-fold in the Control microcosms compared to the Arginine microcosms. The pH-raising effect of arginine was confirmed by the pH and ammonium results. The abundances of sagP and arcA were highest in the Arginine microcosms, while the concentration of butyrate was higher in the Control microcosms. We demonstrate that supplementation with arginine serves a health-promoting function; it enhances microcosm resilience toward acidification and suppresses outgrowth of the opportunistic pathogen Candida. Arginine facilitates stability of oral microbial communities and prevents them from becoming cariogenic. PMID:25433583

  17. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria▿

    PubMed Central

    Johnsen, Anders R.; Schmidt, Stine; Hybholt, Trine K.; Henriksen, Sidsel; Jacobsen, Carsten S.; Andersen, Ole

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation. A nonprimed control microcosm containing pristine soil artificially polluted with PAHs showed only small increases in the numbers of culturable PAH degraders and no pdo1 genes. Initial PAH degradation rates were highest in the primed microcosm, but later, the degradation rates were comparable in primed and nonprimed soil. Thus, the proliferation and persistence of the introduced, soil-adapted degraders had only a marginal effect on PAH degradation. Given the small effect of priming with bioremediated soil and the likely presence of PAH degraders in almost all PAH-contaminated soils, it seems questionable to prime PAH-contaminated soil with bioremediated soil as a means of large-scale soil bioremediation. PMID:17209064

  18. Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

    PubMed

    Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

    2009-02-01

    Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions. PMID:19084427

  19. Microcosm procedure for determining safe levels of chemical exposure in shallow-water communities

    SciTech Connect

    Giddings, J.M.

    1985-01-01

    This paper describes a method for determining safe levels of chemical exposure in shallow-water communities, using laboratory microcosms as test subjects. The safe level is considered to be the maximum exposure that causes no persistent, ecologically significant changes in the ecosystem. In experiments completed at Oak Ridge National Laboratory, microcosm-derived estimates of safe exposure levels were confirmed using outdoor artificial ponds, which suggests that the microcosm procedure can be an efficient and economical means of determining safe levels for shallow-water communities. Details of microcosm construction, techniques for monitoring ecological variables in microcosms, and an experimental design for determining safe exposure levels are provided here. The microcosms are assembled by transferring components of natural ecosystems to 80-litre aquaria in a controlled laboratory environment. The communities that develop in these systems are typically dominated by common, cosmopolitan littoral species of macrophytes, algae, and invertebrates. Methods are described for measuring changes in water chemistry, phytoplankton, periphyton, macrophytes, zooplankton, and ecosystem production and respiration. By monitoring these variables over a gradient of pollutant exposure levels, the safe level can be determined accurately and precisely. 16 refs., 2 figs.

  20. Aerobic Microbial Degradation of Glucoisosaccharinic Acid

    PubMed Central

    Strand, S. E.; Dykes, J.; Chiang, V.

    1984-01-01

    α-Glucoisosaccharinic acid (GISA), a major by-product of kraft paper manufacture, was synthesized from lactose and used as the carbon source for microbial media. Ten strains of aerobic bacteria capable of growth on GISA were isolated from kraft pulp mill environments. The highest growth yields were obtained with Ancylobacter spp. at pH 7.2 to 9.5. GISA was completely degraded by cultures of an Ancylobacter isolate. Ancylobacter cell suspensions consumed oxygen and produced carbon dioxide in response to GISA addition. A total of 22 laboratory strains of bacteria were tested, and none was capable of growth on GISA. GISA-degrading isolates were not found in forest soils. Images PMID:16346467

  1. Biology of Moderately Halophilic Aerobic Bacteria

    PubMed Central

    Ventosa, Antonio; Nieto, Joaquín J.; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

  2. Effect of Municipal Wastewater as a Wetland Water Source on Soil Microbial Activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbial activity, as determined by CO2 evolution, was compared between two soils irrigated with either municipal wastewater effluent or Missouri River water. Irrigation of soils was conducted in greenhouse microcosms with irrigation timing and quantity designed to simulate wetland moist-soil mana...

  3. Aerobic biodegradation of iso-butanol and ethanol and their relative effects on BTEX biodegradation in aquifer materials.

    PubMed

    Schaefer, Charles E; Yang, Xiaomin; Pelz, Oliver; Tsao, David T; Streger, Sheryl H; Steffan, Robert J

    2010-11-01

    The aerobic biodegradability of iso-butanol, a new biofuel, and its impact on benzene, toluene, ethylbenzene and xylenes (BTEX) degradation was investigated in aerobic microcosms consisting of groundwater and sediment from a California site with a history of gasoline contamination. To the best of our knowledge this is the first study directly examining the effects of iso-butanol on BTEX degradation. Microcosms that received either low (68 μM) or high (3400 μM) concentrations of iso-butanol showed complete biodegradation of iso-butanol within 7 and 23 d, respectively, of incubation at 15°C under aerobic conditions. A maximum utilization rate coefficient of 2.3±0.1×10⁻⁷ μmol cell⁻¹ h⁻¹ and a half saturation constant of 610±54 μM were regressed from the iso-butanol data. Iso-butanol biodegradation resulted in transient formation of the degradation intermediate products iso-butylaldehyde and iso-butyric acid, and both compounds were subsequently degraded within the timeframe of the experiments. Ethanol was biodegraded more slowly than iso-butanol. Ethanol also exhibited greater adverse impacts on BTEX biodegradation than iso-butanol. Results of the study suggest that iso-butanol added to fuels will be readily biodegraded in the environment under aerobic conditions without the accumulation of major intermediate products (iso-butylaldehyde and iso-butyric acid), and that it will pose less impacts on BTEX biodegradation than ethanol. PMID:20875664

  4. 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.

  5. Screening Spanish isolates of steinernematid nematodes for use as biological control agents through laboratory and greenhouse microcosm studies.

    PubMed

    Campos-Herrera, Raquel; Gutiérrez, Carmen

    2009-02-01

    Entomopathogenic nematodes (EPNs) are one of the best non-chemical alternatives for insect pest control, with native EPN strains that are adapted to local conditions considered to be ideal candidates for regional biological control programs. Virulence screening of 17 native Mediterranean EPN strains was performed to select the most promising strain for regional insect pest control. Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) Rioja strain produced 7%, 91% and 33% larval mortality for the insects Agriotes sordidus (Illiger) (Coleoptera: Elateridae), Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), respectively, and was selected as the most promising strain. The S. feltiae Rioja strain-S. littoralis combination was considered the most suitable to develop the Rioja strain as a biocontrol agent for soil applications. The effect of soil texture on the virulence of the Rioja strain against S. littoralis was determined through dose-response experiments. The estimated LC(90) to kill larvae in two days was 220, 753 and 4178 IJs/cm(2) for soils with a clay content of 5%, 14% and 24%, respectively, which indicates that heavy soils produced negative effects on the virulence of the Rioja strain. The nematode dose corresponding to the LC(90) for soils with a 5% and 14% clay content reduced insect damage to Capsicum annuum Linnaeus (Solanales: Solanaceae) plants under greenhouse microcosm conditions. The results of this research suggest that an accurate characterization of new EPN strains to select the most suitable combination of insect, nematode and soil texture might provide valuable data to obtain successful biological control under different ecological scenarios in future field applications. PMID:19073191

  6. Stereoselective biodegradation of amphetamine and methamphetamine in river microcosms.

    PubMed

    Bagnall, John; Malia, Louis; Lubben, Anneke; Kasprzyk-Hordern, Barbara

    2013-10-01

    Here presented for the first time is the enantioselective biodegradation of amphetamine and methamphetamine in river microcosm bioreactors. The aim of this investigation was to test the hypothesis that mechanisms governing the fate of amphetamine and methamphetamine in the environment are mostly stereoselective and biological in nature. Several bioreactors were studied over the duration of 15 days (i) in both biotic and abiotic conditions, (ii) in the dark or exposed to light and (iii) in the presence or absence of suspended particulate matter. Bioreactor samples were analysed using SPE-chiral-LC-(QTOF)MS methodology. This investigation has elucidated the fundamental mechanism for degradation of amphetamine and methamphetamine as being predominantly biological in origin. Furthermore, stereoselectivity and changes in enantiomeric fraction (EF) were only observed under biotic conditions. Neither amphetamine nor methamphetamine appeared to demonstrate adsorption to suspended particulate matter. Our experiments also demonstrated that amphetamine and methamphetamine were photo-stable. Illicit drugs are present in the environment at low concentrations but due to their pseudo-persistence and non-racemic behaviour, with two enantiomers revealing significantly different potency (and potentially different toxicity towards aquatic organisms) the risk posed by illicit drugs in the environment should not be under- or over-estimated. The above results demonstrate the need for re-evaluation of the procedures utilised in environmental risk assessment, which currently do not recognise the importance of the phenomenon of chirality in pharmacologically active compounds. PMID:23886544

  7. Arsenic mobilization from sediments in microcosms under sulfate reduction.

    PubMed

    Sun, Jing; Quicksall, Andrew N; Chillrud, Steven N; Mailloux, Brian J; Bostick, Benjamin C

    2016-06-01

    Arsenic is often assumed to be immobile in sulfidic environments. Here, laboratory-scale microcosms were conducted to investigate whether microbial sulfate reduction could control dissolved arsenic concentrations sufficiently for use in groundwater remediation. Sediments from the Vineland Superfund site and the Coeur d'Alene mining district were amended with different combination of lactate and sulfate and incubated for 30-40 days. In general, sulfate reduction in Vineland sediments resulted in transient and incomplete arsenic removal, or arsenic release from sediments. Sulfate reduction in the Coeur d'Alene sediments was more effective at removing arsenic from solution than the Vineland sediments, probably by arsenic substitution and adsorption within iron sulfides. X-ray absorption spectroscopy indicated that the Vineland sediments initially contained abundant reactive ferrihydrite, and underwent extensive sulfur cycling during incubation. As a result, arsenic in the Vineland sediments could not be effectively converted to immobile arsenic-bearing sulfides, but instead a part of the arsenic was probably converted to soluble thioarsenates. These results suggest that coupling between the iron and sulfur redox cycles must be fully understood for in situ arsenic immobilization by sulfate reduction to be successful. PMID:27037658

  8. Microcosm investigation on phytoremediation of Cr using Azolla pinnata.

    PubMed

    Rai, Prabhat Kumar

    2010-01-01

    The extent of Chromium (Cr) pollution in Singrauli industrial region, India was assessed and phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae) was observed to purify waters polluted by Cr under microcosm condition. Azolla pinnata endemic to India is a potential hyper-accumulator of heavy metals. During 13 days of the experiment the fern was grown in the aqueous medium containing Cr3+ and CrO4(2-) ions, each in a concentration 0.5, 1.0, and 3.0 mg L(-1). The presence of these ions caused a + 3.1 to -37.5% inhibition of Azolla pinnata growth in comparison to the control. After 13 days of the experiment, metal contents in the solution was decreased up to 70% (CrO4(2-) 3.0 mg L(-1) treatment) to 88% (CrO4(2-) 0.5 mg L(-1) treatment). In the Azolla pinnata tissues, the concentration of couple of the ionic forms of Cr under investigation ranged from 415 to 1095 mg kg(-1) dry mass (dm); the highest level being found for Cr (III) containing solution. PMID:20734631

  9. Antiseptics and microcosm biofilm formation on titanium surfaces.

    PubMed

    Verardi, Georgia; Cenci, Maximiliano Sérgio; Maske, Tamires Timm; Webber, Bruna; Santos, Luciana Ruschel dos

    2016-01-01

    Oral rehabilitation with osseointegrated implants is a way to restore esthetics and masticatory function in edentulous patients, but bacterial colonization around the implants may lead to mucositis or peri-implantitis and consequent implant loss. Peri-implantitis is the main complication of oral rehabilitation with dental implants and, therefore, it is necessary to take into account the potential effects of antiseptics such as chlorhexidine (CHX), chloramine T (CHT), triclosan (TRI), and essential oils (EO) on bacterial adhesion and on biofilm formation. To assess the action of these substances, we used the microcosm technique, in which the oral environment and periodontal conditions are simulated in vitro on titanium discs with different surface treatments (smooth surface - SS, acid-etched smooth surface - AESS, sand-blasted surface - SBS, and sand-blasted and acid-etched surface - SBAES). Roughness measurements yielded the following results: SS: 0.47 µm, AESS: 0.43 µm, SB: 0.79 µm, and SBAES: 0.72 µm. There was statistical difference only between SBS and AESS. There was no statistical difference among antiseptic treatments. However, EO and CHT showed lower bacterial counts compared with the saline solution treatment (control group). Thus, the current gold standard (CHX) did not outperform CHT and EO, which were efficient in reducing the biofilm biomass compared with saline solution. PMID:26981756

  10. Differential contributions of ammonia oxidizers and nitrite oxidizers to nitrification in four paddy soils

    PubMed Central

    Wang, Baozhan; Zhao, Jun; Guo, Zhiying; Ma, Jing; Xu, Hua; Jia, Zhongjun

    2015-01-01

    Rice paddy fields are characterized by regular flooding and nitrogen fertilization, but the functional importance of aerobic ammonia oxidizers and nitrite oxidizers under unique agricultural management is poorly understood. In this study, we report the differential contributions of ammonia-oxidizing archaea (AOA), bacteria (AOB) and nitrite-oxidizing bacteria (NOB) to nitrification in four paddy soils from different geographic regions (Zi-Yang (ZY), Jiang-Du (JD), Lei-Zhou (LZ) and Jia-Xing (JX)) that are representative of the rice ecosystems in China. In urea-amended microcosms, nitrification activity varied greatly with 11.9, 9.46, 3.03 and 1.43 μg NO3−-N g−1 dry weight of soil per day in the ZY, JD, LZ and JX soils, respectively, over the course of a 56-day incubation period. Real-time quantitative PCR of amoA genes and pyrosequencing of 16S rRNA genes revealed significant increases in the AOA population to various extents, suggesting that their relative contributions to ammonia oxidation activity decreased from ZY to JD to LZ. The opposite trend was observed for AOB, and the JX soil stimulated only the AOB populations. DNA-based stable-isotope probing further demonstrated that active AOA numerically outcompeted their bacterial counterparts by 37.0-, 10.5- and 1.91-fold in 13C-DNA from ZY, JD and LZ soils, respectively, whereas AOB, but not AOA, were labeled in the JX soil during active nitrification. NOB were labeled to a much greater extent than AOA and AOB, and the addition of acetylene completely abolished the assimilation of 13CO2 by nitrifying populations. Phylogenetic analysis suggested that archaeal ammonia oxidation was predominantly catalyzed by soil fosmid 29i4-related AOA within the soil group 1.1b lineage. Nitrosospira cluster 3-like AOB performed most bacterial ammonia oxidation in the ZY, LZ and JX soils, whereas the majority of the 13C-AOB in the JD soil was affiliated with the Nitrosomona communis lineage. The 13C-NOB was overwhelmingly

  11. Biotic and Abiotic Soil Properties Influence Survival of Listeria monocytogenes in Soil

    PubMed Central

    Locatelli, Aude; Spor, Aymé; Jolivet, Claudy; Piveteau, Pascal; Hartmann, Alain

    2013-01-01

    Listeria monocytogenes is a food-borne pathogen responsible for the potentially fatal disease listeriosis and terrestrial ecosystems have been hypothesized to be its natural reservoir. Therefore, identifying the key edaphic factors that influence its survival in soil is critical. We measured the survival of L. monocytogenes in a set of 100 soil samples belonging to the French Soil Quality Monitoring Network. This soil collection is meant to be representative of the pedology and land use of the whole French territory. The population of L. monocytogenes in inoculated microcosms was enumerated by plate count after 7, 14 and 84 days of incubation. Analysis of survival profiles showed that L. monocytogenes was able to survive up to 84 days in 71% of the soils tested, in the other soils (29%) only a short-term survival (up to 7 to 14 days) was observed. Using variance partitioning techniques, we showed that about 65% of the short-term survival ratio of L. monocytogenes in soils was explained by the soil chemical properties, amongst which the basic cation saturation ratio seems to be the main driver. On the other hand, while explaining a lower amount of survival ratio variance (11%), soil texture and especially clay content was the main driver of long-term survival of L. monocytogenes in soils. In order to assess the effect of the endogenous soils microbiota on L. monocytogenes survival, sterilized versus non-sterilized soils microcosms were compared in a subset of 9 soils. We found that the endogenous soil microbiota could limit L. monocytogenes survival especially when soil pH was greater than 7, whereas in acidic soils, survival ratios in sterilized and unsterilized microcosms were not statistically different. These results point out the critical role played by both the endogenous microbiota and the soil physic-chemical properties in determining the survival of L. monocytogenes in soils. PMID:24116083

  12. BACTERIAL COMMUNITY DYNAMICS AND ECOTOXICOLOGICAL ASSESSMENT DURING BIOREMEDIATION OF SOILS CONTAMINATED BY BIODIESEL AND DIESEL/BIODIESEL BLENDS.

    PubMed

    Matos, G I; Junior, C S; Oliva, T C; Subtil, D F; Matsushita, L Y; Chaves, A L; Lutterbach, M T; Sérvulo, E F; Agathos, S N; Stenuit, B

    2015-01-01

    The gradual introduction of biodiesel in the Brazilian energy landscape has primarily occurred through its blending with conventional petroleum diesel (e.g., B20 (20% biodiesel) and B5 (5% biodiesel) formulations). Because B20 and lower-level blends generally do not require engine modifications, their use as transportation fuel is increasing in the Brazilian distribution networks. However, the environmental fate of low-level biodiesel blends and pure biodiesel (B100) is poorly understood and the ecotoxicological-safety endpoints of biodiesel-contaminated environments are unknown. Using laboratory microcosms consisting of closed reactor columns filled with clay loam soil contaminated with pure biodiesel (EXPB100) and a low-level blend (EXPB5) (10% w/v), this study presents soil ecotoxicity assessement and dynamics of culturable heterotrophic bacteria. Most-probable-number (MPN) procedures for enumeration of bacteria, dehydrogenase assays and soil ecotoxicological tests using Eisenia fetida have been performed at different column depths over the course of incubation. After 60 days of incubation, the ecotoxicity of EXPB100-derived samples showed a decrease from 63% of mortality to 0% while EXPB5-derived samples exhibited a reduction from 100% to 53% and 90% on the top and at the bottom of the reactor column, respectively. The dehydrogenase activity of samples from EXPB100 and EXPB5 increased significantly compared to pristine soil after 60 days of incubation. Growth of aerobic bacterial biomass was only observed on the top of the reactor column while the anaerobic bacteria exhibited significant growth at different column depths in EXPB100 and EXPB5. These preliminary results suggest the involvement of soil indigenous microbiota in the biodegradation of biodiesel and blends. However, GC-FID analyses for quantification of fatty acid methyl esters (FAMEs) and aliphatic hydrocarbons and targeted sequencing of 16S rRNA tags using illumina platforms will provide important

  13. Enhancing petroleum hydrocarbon biodegradation in soils with surfactant/nutrients

    SciTech Connect

    Nelson, E.C.; Walter, M.V.; Bossert, I.D.

    1995-12-31

    Bioremediation of hydrocarbon contaminated soils is an attractive process for treating contaminated soils because it converts contaminants into harmless byproducts at low costs. However, the process is slow; rates of cleanup are typically measured in months or years. The process could be improved with additives that accelerate rates of biodegradation. In this study, molecular surfactant/nutrients were synthesized and tested for their ability to enhance the biodegradation of petroleum hydrocarbon contaminants in soils. Rates of biodegradation of heavy hydrocarbons were evaluated using either oxygen and carbon dioxide respirometry in soil slurries, or periodic measurements of extractable hydrocarbon residues in unsaturated soil microcosms. Results show rate enhancements in both soil slurries and unsaturated soil microcosms that were treated with an anionic nitrogenous surfactant.

  14. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  15. Bacterial Community Response to Petroleum Hydrocarbon Amendments in Freshwater, Marine, and Hypersaline Water-Containing Microcosms

    PubMed Central

    Jurelevicius, Diogo; Alvarez, Vanessa Marques; Marques, Joana Montezano; de Sousa Lima, Laryssa Ribeiro Fonseca; Dias, Felipe de Almeida

    2013-01-01

    Hydrocarbon-degrading bacterial communities from freshwater, marine, and hypersaline Brazilian aquatic ecosystems (with water salinities corresponding to 0.2%, 4%, and 5%, respectively) were enriched with different hydrocarbons (heptadecane, naphthalene, or crude oil). Changes within the different microcosms of bacterial communities were analyzed using cultivation approaches and molecular methods (DNA and RNA extraction, followed by genetic fingerprinting and analyses of clone libraries based on the 16S rRNA-coding gene). A redundancy analysis (RDA) of the genetic fingerprint data and a principal component analysis (PCA) of the clone libraries revealed hydrocarbon-enriched bacterial communities specific for each ecosystem studied. However, within the same ecosystem, different bacterial communities were selected according to the petroleum hydrocarbon used. In general, the results demonstrated that Acinetobacter and Cloacibacterium were the dominant genera in freshwater microcosms; the Oceanospirillales order and the Marinobacter, Pseudomonas, and Cycloclasticus genera predominated in marine microcosms; and the Oceanospirillales order and the Marinobacter genus were selected in the different hydrocarbon-containing microcosms in hypersaline water. Determination of total petroleum hydrocarbons (TPHs) in all microcosms after 32 days of incubation showed a decrease in the hydrocarbon concentration compared to that for the controls. A total of 50 (41.3%) isolates from the different hydrocarbon-contaminated microcosms were associated with the dominant operational taxonomic units (OTUs) obtained from the clone libraries, and their growth in the hydrocarbon contaminating the microcosm from which they were isolated as the sole carbon source was observed. These data provide insight into the general response of bacterial communities from freshwater, marine, and hypersaline aquatic ecosystems to petroleum hydrocarbon contamination. PMID:23872573

  16. Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex.

    PubMed

    Abuhani, W A; Dasgupta-Schubert, N; Villaseñor, L M; García Avila, D; Suárez, L; Johnston, C; Borjas, S E; Alexander, S A; Landsberger, S; Suárez, M C

    2015-01-01

    The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to

  17. The medically important aerobic actinomycetes: epidemiology and microbiology.

    PubMed Central

    McNeil, M M; Brown, J M

    1994-01-01

    The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes. Images PMID:7923055

  18. Aerobic biodegradation of sludge with high hydrocarbon content generated by a Mexican natural gas processing facility.

    PubMed

    Roldán-Carrillo, T; Castorena-Cortés, G; Zapata-Peñasco, I; Reyes-Avila, J; Olguín-Lora, P

    2012-03-01

    The biodegradation of oil sludge from Mexican sour gas and petrochemical facilities contaminated with a high content of hydrocarbons, 334.7 ± 7.0 g kg(-1) dry matter (dm), was evaluated. Studies in microcosm systems were carried out in order to determine the capacity of the native microbiota in the sludge to reduce hydrocarbon levels under aerobic conditions. Different carbon/nitrogen/phosphorous (C/N/P) nutrient ratios were tested. The systems were incubated at 30 °C and shaken at 100 rpm. Hydrocarbon removals from 32 to 51% were achieved in the assays after 30 days of incubation. The best assay had C/N/P ratio of 100/1.74/0.5. The results of the Microtox(®) and Ames tests indicated that the original sludge was highly toxic and mutagenic, whereas the best assay gave a final product that did not show toxicity or mutagenicity. PMID:21600691

  19. "Aerobic" Writing: A Writing Practice Model.

    ERIC Educational Resources Information Center

    Crisp, Sally Chandler

    "Aerobic writing" is a writing center strategy designed to keep students in writing "shape." Like aerobic exercise, aerobic writing is sustained for a certain length of time and done on a regular basis at prescribed time intervals. The program requires students to write at least two times a week for approximately an hour each time. Students write,…

  20. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  1. Effects of N and P fertilisation on greenhouse gas (GHG) production in floodplain fen peat: A microcosm fertilisation experiment.

    NASA Astrophysics Data System (ADS)

    Stanley, Kieran; Heppell, Catherine; Belyea, Lisa; Baird, Andrew

    2016-04-01

    CH4 production. Samples fertilised with P+G had the highest CH4 production (ANCOVA, between factors: treatment and site; covariate: time; F4,120= 15.026, p < 0.001). Samples fertilised with N (N+G and N+P+G) showed CH4 inhibition in comparison to G and P+G additions. CH4 production was significantly greater from the nutrient-rich peat than from the lower-nutrient peat (ANCOVA, between factors: treatment and site; covariate: time; F1,120= 38.646, p < 0.01). However, a decline in CH4 concentration in the microcosms suggests that CH4 oxidation occurred after 150 hours at the lower-nutrient site. Owing to the anaerobic conditions within the microcosms, aerobic methanotrophy cannot occur, suggesting anaerobic CH4 oxidation occurred along with denitrification. However, NO and N2 concentrations were not measured in this study, so this suggestion requires examination in future work.

  2. Multilevel samplers as microcosms to assess microbial response to biostimulation.

    PubMed

    Baldwin, B R; Peacock, A D; Park, M; Ogles, D M; Istok, J D; McKinley, J P; Resch, C T; White, D C

    2008-01-01

    Passive multilevel samplers (MLS) containing a solid matrix for microbial colonization were used as in situ microcosms in conjunction with a push-pull biostimulation experiment designed to promote biological U(VI) and Tc(VII) reduction. MLS were deployed at 24 elevations in the injection well and two downgradient wells to investigate the spatial variability in microbial community composition and growth prior to and following biostimulation. The microbial community was characterized by real-time quantitative polymerase chain reaction (Q-PCR) quantification of bacteria, NO(3)(-)-reducing bacteria (nirS and nirK), delta-proteobacteria, Geobacter sp., and methanogens (mcrA). Pretest cell densities were low overall but varied substantially with significantly greater bacterial populations detected at circumneutral pH (t-test, alpha= 0.05), suggesting carbon substrate and low pH limitations of microbial activity. Although pretest cell densities were low, denitrifying bacteria were dominant members of the microbial community. Biostimulation with an ethanol-amended ground water resulted in concurrent NO(3)(-) and Tc(VII) reduction, followed by U(VI) reduction. Q-PCR analysis of MLS revealed significant (1 to 2 orders of magnitude, Mann-Whitney U-test, alpha= 0.05) increases in cell densities of bacteria, denitrifiers, delta-proteobacteria, Geobacter sp., and methanogens in response to biostimulation. Traditionally, characterization of sediment samples has been used to investigate the microbial community response to biostimulation; however, collection of sediment samples is expensive and not conducive to deep aquifers or temporal studies. The results presented demonstrate that push-pull tests with passive MLS provide an inexpensive approach to determine the effect of biostimulation on contaminant concentrations, geochemical conditions, and the microbial community composition and function. PMID:18194316

  3. Microcosms metacommunities in river network: niche effects and biodiversity

    NASA Astrophysics Data System (ADS)

    Giometto, A.; Carrara, F.; Altermatt, F.; Rinaldo, A.

    2012-04-01

    Many highly diverse landscapes exhibit hierarchical spatial structures that are shaped by geomorphological processes. Riverine ecosystems, among the most diverse habitats on Earth, represent an outstanding example of such mechanisms. In these landscapes, in which connectivity directly influences metacommunity processes, habitat capacity contributes to control biodiversity at several levels. A previous study has already highlighted the effect of connectivity on species distribution at local and regional scales, but habitat capacity was kept uniform. We studied the interaction of connectivity and habitat capacity in an aquatic microcosm experiment, in which microbial communities were grown in 36-well culture plates connected by dispersal. Dispersal occurred by periodic transfer of culture medium among connected local communities, following river network topology. The effect of habitat capacity in these landscapes was investigated by comparing three different spatial configurations of local community volumes: 1. Power law distributed volumes, according to drainage area. 2. Spatial random permutation of the volumes in the above configuration. 3. Equal distribution of volumes (preserving the total volume with respect to the above configurations). The net effect of habitat capacity on community composition was isolated in a control treatment in which communities were kept isolated for the whole duration of the experiment. In all treatments we observed that varying volumes induced niche effects: some protozoan species preferentially occupied larger nodes (systematically in isolation). Nevertheless, there is evidence that position along the network played a significant role in shaping biodiversity patterns. Size distribution measurements for each community were taken with a CASY cell counter, and species abundances data on log scale precision were collected by direct microscope observation.

  4. Toxic effects of isoproturon on periphyton communities a microcosm study

    NASA Astrophysics Data System (ADS)

    Schmitt-Jansen, Mechthild; Altenburger, Rolf

    2005-02-01

    Coastal and estuarine ecosystems are increasingly exposed to herbicide contamination. To study the potential risks of these pollutants, the establishment of periphyton communities under exposure of a concentration series of isoproturon in a range of 0.0024-0.312 mg L -1 was investigated in a microcosm study. After two weeks of growth, chronic effects on biomass development, measured as Chl a fluorescence, taxonomic composition and photosynthetic capacity of PS II of attached microalgae were analysed using a pulse-amplitude modulated (PAM) fluorescence-based method. Algal classes were differentiated according to their pigment systems using four excitation wavelengths. Biomass remained constant up to pre-exposure concentrations of 0.02 mg L -1 isoproturon but decreased within one order of magnitude at the highest test concentration. Algal classes shifted from diatoms to chlorophytes at pre-exposure concentrations of 0.02-0.39 mg L -1. Community structure of diatoms representing the dominant group of attached algae at lower test concentrations was studied by microscopic analysis revealing that species numbers were highest at lowest test concentrations as compared to controls. At higher test concentrations Navicula halophila dominated with 89% of the diatom biomass but was abnormally shaped. Pollution-induced community tolerance (PICT) of periphyton to isoproturon was determined by short-term inhibition tests of photosynthesis. Pre-exposed communities increased their effect concentrations (EC 50) up to threefold within the 0.039 mg L -1 pre-treatment. Our results suggest that attached microalgal communities have a high potential of tolerance development to isoproturon at lower levels of contamination due to the replacement of sensitive species by more tolerant algae, although these species seemed to be affected too. We conclude that herbicide concentrations in river basins, estuaries or coastal zones may change community structure and primary production of

  5. Plant growth and the performance of mangrove wetland microcosms for mariculture effluent depuration.

    PubMed

    Su, Yung-Ming; Lin, Ying-Feng; Jing, Shuh-Ren; Hou, Ping-Chun Lucy

    2011-07-01

    This study established wetland microcosms that were either unplanted or planted in monoculture with native mangrove species in Taiwan (Avicennia marina, Rhizophora stylosa, and Lumnitzera racemosa) for the purpose of receiving high-salinity mariculture effluents; additionally, the microcosms operated at different hydraulic retention times (HRTs). Plant growth and the performance of the microcosms with respect to pollutant removal were investigated. The results showed that seedlings of all three mangrove species survived and grew sufficiently well under continuous flooding. The presence of mangroves consistently improved SS, BOD(5), and TP removal, particularly under short HRT conditions. The mangrove microcosms removed pollutants from the mariculture effluents with efficiencies of 5.7-27.1% (SS), 4.9-36.3% (BOD(5)), 18.7-29.9% (TP), 21.2-49.8% (NH(4)-N), and 5.4-37.7% (NO(x)-N). A. marina and L. racemosa were more tolerant of continuous flooding than R. stylosa. However, no species displayed consistently superior performance in decreasing all pollutant-related parameters investigated. For all pollutants, microcosms operating at a 2-d HRT exhibited a higher removal efficiency than those operating at a 0.5-d HRT. PMID:21561629

  6. A microbial functional group-based module for simulating methane production and consumption: Application to an incubated permafrost soil

    NASA Astrophysics Data System (ADS)

    Xu, Xiaofeng; Elias, Dwayne A.; Graham, David E.; Phelps, Tommy J.; Carroll, Sue L.; Wullschleger, Stan D.; Thornton, Peter E.

    2015-07-01

    Accurately estimating methane (CH4) flux in terrestrial ecosystems is critically important for investigating and predicting biogeochemistry-climate feedbacks. Improved simulations of CH4 flux require explicit representations of the microbial processes that account for CH4 dynamics. A microbial functional group-based module was developed, building on the decomposition subroutine of the Community Land Model 4.5. This module considers four key mechanisms for CH4 production and consumption: methanogenesis from acetate or from single-carbon compounds and CH4 oxidation using molecular oxygen or other inorganic electron acceptors. Four microbial functional groups perform these processes: acetoclastic methanogens, hydrogenotrophic methanogens, aerobic methanotrophs, and anaerobic methanotrophs. This module was used to simulate dynamics of carbon dioxide (CO2) and CH4 concentrations from an incubation experiment with permafrost soils. The results show that the model captures the dynamics of CO2 and CH4 concentrations in microcosms with top soils, mineral layer soils, and permafrost soils under natural and saturated moisture conditions and three temperature conditions of -2°C, 3°C, and 5°C (R2 > 0.67 P < 0.001). The biases for modeled results are less than 30% across the soil samples and moisture and temperature conditions. Sensitivity analysis confirmed the importance of acetic acid's direct contribution as substrate and indirect effects through pH feedback on CO2 and CH4 production and consumption. This study suggests that representing the microbial mechanisms is critical for modeling CH4 production and consumption; it is urgent to incorporate microbial mechanisms into Earth system models for better predicting trace gas dynamics and the behavior of the climate system.

  7. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS2003 on microcosm oil spill simulation

    PubMed Central

    Cappello, Simone; Genovese, Maria; Denaro, Renata; Santisi, Santina; Volta, Anna; Bonsignore, Martina; Mancini, Giuseppe; Giuliano, Laura; Genovese, Lucrezia; Yakimov, Michail M.

    2014-01-01

    Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS2003) on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS2003 (SW+OIL+EPS2003); this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS2003 could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process. PMID:25763036

  8. Fungal diversity and ecosystem function data from wine fermentation vats and microcosms.

    PubMed

    Boynton, Primrose J; Greig, Duncan

    2016-09-01

    Grape must is the precursor to wine, and consists of grape juice and its resident microbial community. We used Illumina MiSeq® to track changes in must fungal community composition over time in winery vats and laboratory microcosms. We also measured glucose consumption and biomass in microcosms derived directly from must, and glucose consumption in artificially assembled microcosms. Functional impacts of individual must yeasts in artificially assembled communities were calculated using a "keystone index," developed for "Species richness influences wine ecosystem function through a dominant species" [1]. Community composition data and functional measurements are included in this article. DNA sequences were deposited in GenBank (GenBank: SRP073276). Discussion of must succession and ecosystem functioning in must are provided in [1]. PMID:27331092

  9. The fate of antibiotic resistance genes and class 1 integrons following the application of swine and dairy manure to soils.

    PubMed

    Sandberg, Kyle D; LaPara, Timothy M

    2016-02-01

    The goal of this study was to determine the fate of antibiotic resistance genes (ARGs) and class 1 integrons following the application of swine and dairy manure to soil. Soil microcosms were amended with either manure from swine fed subtherapeutic levels of antibiotics or manure from dairy cows that were given antibiotics only rarely and strictly for veterinary purposes. Microcosms were monitored for 6 months using quantitative PCR targeting 16S rRNA genes (a measure of bacterial biomass), intI1, erm(B), tet(A), tet(W) and tet(X). Swine manure had 10- to 100-fold higher levels of ARGs than the dairy manure, all of which decayed over time after being applied to soil. A modified Collins-Selleck model described the decay of ARGs in the soil microcosms well, particularly the characteristic in which the decay rate declined over time. By the completion of the soil microcosm experiments, ARGs in the dairy manure-amended soils returned to background levels, whereas the ARGs in swine manure remained elevated compared to control microcosms. Our research suggests that the use of subtherapeutic use of antibiotics in animal feed could lead to the accumulation of ARGs in soils to which manure is applied. PMID:26738555

  10. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  11. BIOREMEDIATION OF MIXED VAPOR PHASE CONTAMINANTS FROM SOILS AND GROUNDWATER

    EPA Science Inventory

    Soil vapor phase contaminants commonly include combinations of chlorinated ethenes and petroleum hydrocarbons. Many chlorinated ethenes and petroleum hydrocarbons are readily degradable by a range of aerobic soil microorganisms, making the use of biological systems for degrading ...

  12. Stimulation of Mercury Methylation by Coal Ash in Anaerobic Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Schwartz, G.; Hsu-Kim, H.; Redfern, L.; Gunsch, C.; Vengosh, A.

    2015-12-01

    Coal combustion products (coal ash) represent one of the largest industrial waste streams in the United States. Coal ash contains elevated levels of toxic, bioaccumulative elements such as mercury (Hg), yet the majority of coal ash waste is stored in unlined impoundments and landfills. These impoundments have a long history of environmental degradation, including: groundwater contamination, surface water contamination through impoundment effluent discharge, and impoundment failures resulting in catastrophic ash release events. The fate of toxic elements associated with coal ash is greatly influenced by environmental parameters, such as redox potential and microbial activity, which induce transformations and leaching of contaminants. Here we used anaerobic sediment-ash microcosms to determine how coal ash impacts methyl mercury (MeHg) production in a simulated benthic aquatic environment. We used two coal ash types in the microcosms: a weathered ash with low sulfate/Hg content and a fresh fly ash that was relatively enriched in sulfate/Hg compared to the weathered ash. Two different sediments were used in the microcosms: one was a pristine sediment (containing 0.03 mg/kg Hg) and the other was a relatively Hg-contaminated sediment (containing 0.29 mg/kg Hg). Results showed that microcosms amended with the low sulfate/low Hg ash had no net MeHg production. In contrast, microcosms amended with high sulfate/high Hg ash showed increases in MeHg concentrations that were 2 to 3 times greater than control microcosms without ash, indicating that coal ash can stimulate MeHg production by providing spikes of Hg and labile sulfate to the aquatic system. MeHg production in ash-amended microcosms containing contaminated sediment was no greater than in the ash-amended pristine sediment microcosms. This may indicate that Hg associated with coal ash is more bioavailable than the Hg present in historically contaminated sediments. Illumina sequencing is underway to investigate the

  13. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  14. Soil Communities Promote Temporal Stability and Species Asynchrony in Experimental Grassland Communities

    PubMed Central

    Pellkofer, Sarah; van der Heijden, Marcel G. A.; Schmid, Bernhard; Wagg, Cameron

    2016-01-01

    Background Over the past two decades many studies have demonstrated that plant species diversity promotes primary productivity and stability in grassland ecosystems. Additionally, soil community characteristics have also been shown to influence the productivity and composition of plant communities, yet little is known about whether soil communities also play a role in stabilizing the productivity of an ecosystem. Methodology/Principal Findings Here we use microcosms to assess the effects of the presence of soil communities on plant community dynamics and stability over a one-year time span. Microcosms were filled with sterilized soil and inoculated with either unaltered field soil or field soil sterilized to eliminate the naturally occurring soil biota. Eliminating the naturally occurring soil biota not only resulted in lower plant productivity, and reduced plant species diversity, and evenness, but also destabilized the net aboveground productivity of the plant communities over time, which was largely driven by changes in abundance of the dominant grass Lolium perenne. In contrast, the grass and legumes contributed more to net aboveground productivity of the plant communities in microcosms where soil biota had been inoculated. Additionally, the forbs exhibited compensatory dynamics with grasses and legumes, thus lowering temporal variation in productivity in microcosms that received the unaltered soil inocula. Overall, asynchrony among plant species was higher in microcosms where an unaltered soil community had been inoculated, which lead to higher temporal stability in community productivity. Conclusions/Significance Our results suggest that soil communities increase plant species asynchrony and stabilize plant community productivity by equalizing the performance among competing plant species through potential antagonistic and facilitative effects on individual plant species. PMID:26829481

  15. Methods to determine aerobic endurance.

    PubMed

    Bosquet, Laurent; Léger, Luc; Legros, Patrick

    2002-01-01

    Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate

  16. IMPORTANCE OF PHYSICAL SCALING FACTORS TO BENTHIC MARINE INVERTEBRATE RECOLONIZATION OF LABORATORY MICROCOSMS

    EPA Science Inventory

    Five laboratory studies of benthic macroinvertebrate recolonization were conducted for 6-wk periods to evaluate the effects of physical factors (i.e., microcosm size, seawater flow rates and sediment depth) on benthic community structure. esign variables included4 open-faced acry...

  17. STIMULATION OF THE REDUCTIVE DECHLORINATION OF TETRACHLOROETHENE IN ANAEROBIC AQUIFER MICROCOSMS BY THE ADDITION OF TOLUENE

    EPA Science Inventory

    In this study, the biologically mediated interactions of toluene and PCE under anaerobic conditions were investigated by using microcosms constructed with aquifer solids from an area that was exposed to both alkylbenzenes and chlorinated ethenes at the U.S. Coast Guard Air Statio...

  18. Effects Of Nutrient Source And Supply On Crude Oil Biodegradation In Continuous-Flow Beach Microcosms

    EPA Science Inventory

    Ammonium and nitrate were used as nitrogen sources to support microbial biodegradation of crude oil in continuous-flow beach microcosms to determine whether either nutrient was more effective in open systems, such as intertidal shorelines. No differences in the rate or the exten...

  19. Methanogenic degradation kinetics of phenolic compounds in aquifer-derived microcosms

    USGS Publications Warehouse

    Godsy, E.M.; Goerlitz, D.F.; Grbic-Galic, D.

    1992-01-01

    In this segment of a larger multidisciplinary study of the movement and fate of creosote derived compounds in a sand-and-gravel aquifer, we present evidence that the methanogenic degradation of the major biodegradable phenolic compounds and concomitant microbial growth in batch microcosms derived from contaminated aquifer material can be described using Monod kinetics. Substrate depletion and bacterial growth curves were fitted to the Monod equations using nonlinear regression analysis. The method of Marquardt was used for the determination of parameter values that best fit the experimental data by minimizing the residual sum of squares. The Monod kinetic constants (??max, Ks, Y, and kd) that describe phenol, 2-, 3-, and 4-methylphenol degradation and concomitant microbial growth were determined under conditions that were substantially different from those previously reported for microcosms cultured from sewage sludge. The Ks values obtained in this study are approximately two orders of magnitude lower than values obtained for the anaerobic degradation of phenol in digesting sewage sludge, indicating that the aquifer microorganisms have developed enzyme systems that are adapted to low nutrient conditions. The values for kd are much less than ??max, and can be neglected in the microcosms. The extremely low Y values, approximately 3 orders of magnitude lower than for the sewage sludge derived cultures, and the very low numbers of microorganisms in the aquifer derived microcosms suggest that these organisms use some unique strategies to survive in the subsurface environment. ?? 1992 Kluwer Academic Publishers.

  20. INFLUENCE OF SOLID SURFACE, ADHESIVE ABILITY, AND INOCULUM SIZE ON BACTERIAL COLONIZATION IN MICROCOSM STUDIES

    EPA Science Inventory

    Microcosm studies were performed to evaluate the effect of solid surfaces, bacterial adhesive ability, and inoculum size on colonization success and persistence of P. fluorescens or X maltophilia, each with a Tn5 insertion that conferred resistance to kanamycin and streptomycin. ...

  1. Creating a Community. A Microcosm that Develops Career Awareness. Career Development Program.

    ERIC Educational Resources Information Center

    Winograd, Myra

    Intended for use by teachers in elementary and junior high schools, this booklet offers ten classroom activities to create a community microcosm which would enable students to develop awareness of career opportunities and of community values and priorities. As a lead-in exercise, lesson 1 suggests two films for the class to view and discuss.…

  2. EFFECTS OF MICROCOSM PREPARATION ON RATES OF TOLUENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS

    EPA Science Inventory

    Microcosms were prepared with subsurface material from two aquifers to examine the effects of preparation methods on rates of toluene biodegradation under denitrifying conditions. In both cases, the data fit a zero-order kinetics plot. However, rates of removal were generally pro...

  3. LONG-TERM SURVIVAL AND PLASMID MAINTENANCE OF ESCHERICHIA COLI IN MARINE MICROCOSMS

    EPA Science Inventory

    The survival pattern and plasmid maintenance of Escherichia con was examined in an artificial seawater microcosm. t was found that the three strain, of E. coli (EK3C, H10407 and 34309) included in the study were able to maintain a portion of cells in the culturable phase for at l...

  4. Enrichment of anaerobic benzene-degrading microorganisms by in situ microcosms.

    PubMed

    Herrmann, Steffi; Kleinsteuber, Sabine; Neu, Thomas R; Richnow, Hans Hermann; Vogt, Carsten

    2008-01-01

    Microcosms filled with different solids (sand, lava, Amberlite XAD-7) were exposed for 67 days in the sulfidic part of a groundwater monitoring well downstream of the source zone of a benzene-contaminated aquifer and subsequently incubated in the laboratory. Benzene was repeatedly degraded in several microcosms accompanied by production of sulfide, leading to stable benzene-degrading enrichment cultures. In control microcosms without filling material, benzene was initially degraded, but the benzene-degrading capacity could not be sustained. The results indicate that long-term physiologically active benzene-degrading microorganisms were attached to surfaces of the solids. The biodiversity and attachment behavior of microorganisms in the in situ microcosms was assessed by confocal laser scanning microscopy and single-strand conformation polymorphism (SSCP) analysis, followed by sequencing of dominant SSCP bands. The microbial community was composed of several different Bacteria, representing members of Clostridia, Bacteroidales, all subgroups of the Proteobacteria, Verrucomicrobia, Nitrospira, Chloroflexi and Chlorobi. Only a few archaeal sequences could be retrieved from the communities. The majority of phylotypes were affiliated to bacterial groups with a possible functional relationship to the bacterial sulfur cycle, thus indicating that the microbial community in the investigated aquifer zone depends mainly on inorganic sulfur compounds as electron donors or acceptors, a finding that corresponds to the geochemical data. PMID:18081593

  5. MICROCOSM FOR MEASURING SURVIVAL AND CONJUGATION OF GENETICALLY ENGINEERED BACTERIA IN RHIZOSPHERE ENVIRONMENTS

    EPA Science Inventory

    A microcosm is described to evaluate and measure bacterial conjugation in the rhizosphere of barley and radish with strains of Pseudomonas cepacia. he purpose was to describe a standard method useful for evaluating the propensity of genetically engineered microorganisms (GEMs) to...

  6. CONJUGAL TRANSFER AT NATURAL POPULATION DENSITIES IN A MICROCOSM SIMULATING AN ESTUARINE ENVIRONMENT

    EPA Science Inventory

    Estuarine microcosms were used to follow conjugal transfer of a broad host range IncP1 plasmid from a Pseudomonas putida donor to indigenous bacteria. onor cells were added at a concentration similar to the natural abundance of bacteria in the water column (10 6/mi). ransfer was ...

  7. Enumeration and Biomass Estimation of Bacteria in Aquifer Microcosm Studies by Flow Cytometry

    PubMed Central

    DeLeo, P. C.; Baveye, P.

    1996-01-01

    Flow cytometry was used to enumerate and characterize bacteria from a sand column microcosm simulating aquifer conditions. Pure cultures of a species of Bacillus isolated from subsurface sediments or Bacillus megaterium were first evaluated to identify these organisms' characteristic histograms. Counting was then carried out with samples from the aquifer microcosms. Enumeration by flow cytometry was compared with more-traditional acridine orange direct counting. These two techniques gave statistically similar results. However, counting by flow cytometry, in this case, surveyed a sample size 700 times greater than did acridine orange direct counting (25 (mu)l versus 0.034 (mu)l) and required 1/10 the time (2 h versus 20 h). Flow cytometry was able to distinguish the same species of bacteria grown under different nutrient conditions, and it could distinguish changes in cell growth patterns, specifically single cell growth versus chained cell growth in different regions of an aquifer microcosm. A biomass estimate was calculated by calibrating the total fluorescence of a sample from a pure culture with the dry weight of a freeze-dried volume from the original pure culture. Growth conditions significantly affected histograms and biomass estimates, so the calibration was carried out with cells grown under conditions similar to those in the aquifer microcosm. Costs associated with using flow cytometry were minimal compared with the amount of time saved in counting cells and estimating biomass. PMID:16535470

  8. EPA worst case water microcosms for testing phage biocontrol of Salmonella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method using laboratory microcosms is proposed for evaluating the effectiveness of selected phages for biocontrol of Salmonella within swine effluent and manure impacted environments. The method uses EPA (U.S. Environmental Protection Agency) worst case water as a high organic matter matrix to s...

  9. EFFECTS OF FLUORENE ON MICROCOSMS DEVELOPED FROM FOUR NATURAL COMMUNITIES (JOURNAL VERSION)

    EPA Science Inventory

    Ecosystem-level responses were examined in microcosms developed from four different natural plankton communities and exposed to nominal concentrations of 0.12, 0.50, 2.0, 5.0 and 10.0 mg/L fluorene. The lowest observed effect level (LOEL) for dark respiration was 0.12 mg/L fluore...

  10. ADAPTATION OF MIXED FLASK CULTURE MICROCOSMS FOR TESTING THE SURVIVAL AND EFFECTS OF INTRODUCED MICROORGANISMS

    EPA Science Inventory

    A microcosm test was used to evaluate the survival and effects of Bacillus thuringiensis var. israelinsis (Bti) in aquatic systems. wo commercial formulations (Vectobac tm from Abbot; Mosquito Attack tm form Aeuters Laboratories) and a laboratory preparation of Bti spores were te...

  11. Sorption and photo degradation processes govern distribution of sulfamethazine in freshwater-sediment microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation and fate of sulfamethazine in surface water using 14C-phenyl-sulfamethazine in small pond water microcosms containing intact sediment and pond water. We found a 2.7-d half-li...

  12. Effect of isobutanol on toluene biodegradation in nitrate amended, sulfate amended and methanogenic enrichment microcosms.

    PubMed

    Jayamani, Indumathy; Cupples, Alison M

    2013-09-01

    Isobutanol is an alternate fuel additive that is being considered because of economic and lower emission benefits. However, future gasoline spills could result in co-contamination of isobutanol with gasoline components such as benzene, toluene, ethyl-benzene and xylene. Hence, isobutanol could affect the degradability of gasoline components thereby having an effect on contaminant plume length and half-life. In this study, the effect of isobutanol on the biodegradation of a model gasoline component (toluene) was examined in laboratory microcosms. For this, toluene and isobutanol were added to six different toluene degrading laboratory microcosms under sulfate amended, nitrate amended or methanogenic conditions. While toluene biodegradation was not greatly affected in the presence of isobutanol in five out of the six different experimental sets, toluene degradation was completely inhibited in one set of microcosms. This inhibition occurred in sulfate amended microcosms constructed with inocula from wastewater treatment plant activated sludge. Our data suggest that toluene degrading consortia are affected differently by isobutanol addition. These results indicate that, if co-contamination occurs, in some cases the in situ half-life of toluene could be significantly extended. PMID:23224907

  13. Fate of Sulfamethazine in Surface Water Microcosms and Bioaccumulation in Sediment-dwelling Invertebrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation and fate of sulfamethazine in small pond water microcosms using 14C-phenyl-sulfamethazine, and found a 2.7-d half-life in pond water and 4.2-d half-life when added to the wat...

  14. ENANTIOSELECTIVE REDUCTIVE TRANSFORMATION OF CHIRAL POLYCHLORINATED BIPHENYLS IN LAKE SEDIMENT MICROCOSMS

    EPA Science Inventory

    The transformation rates and enantiomeric ratios of two chiral poylchlorinated biphenyls (PCBs), 2,2',3,4',5',6-hexachlorobiphenyl (2,2',3,4',5',6-HCB) and 2,2',3,3',4,4',5,6-octachlorobiphenyl (2,2',3,3',4,4',5,6-OCB), were determined in anaerobic lake sediment microcosms (25oC)...

  15. The Institution of Carlisle School: A Microcosm of 500 Years of Indian Policy.

    ERIC Educational Resources Information Center

    Fine, Mike

    The history of the Carlisle Indian Boarding School is a microcosm of 500 years of Indian policy. Established through the efforts of career military man Richard Pratt in 1879, the school symbolized the emerging view of assimilation, an important change from earlier attempts at genocide and prior militant attitudes towards the Indians. Long…

  16. Aerobic granular processes: Current research trends.

    PubMed

    Zhang, Quanguo; Hu, Jianjun; Lee, Duu-Jong

    2016-06-01

    Aerobic granules are large biological aggregates with compact interiors that can be used in efficient wastewater treatment. This mini-review presents new researches on the development of aerobic granular processes, extended treatments for complicated pollutants, granulation mechanisms and enhancements of granule stability in long-term operation or storage, and the reuse of waste biomass as renewable resources. A discussion on the challenges of, and prospects for, the commercialization of aerobic granular process is provided. PMID:26873285

  17. Variability of biological degradation of phenolic hydrocarbons in an aerobic aquifer determined by laboratory batch experiments

    NASA Astrophysics Data System (ADS)

    Nielsen, Per H.; Christensen, Thomas H.

    1994-11-01

    The biological aerobic degradation of 7 phenolic hydrocarbons (phenol, o-cresol, o-nitrophenol, p-nitrophenol, 2,6-dichlorophenol, 2,4-dichlorophenol, 4,6- o-dichlorocresol) and 1 aromatic hydrocarbon (nitrobenzene) was studied for 149 days in replicate laboratory batch microcosms with sediment and groundwater from 8 localities representing a 15 m × 30 m section of an aerobic aquifer. Three patterns of variation were found: (1) phenol, o-cresol and in most cases p-nitrophenol showed very fast degradation with no or only short lag phases and with very little variation among localities; (2) 2,4-dichlorophenol was degraded in all localities and showed large variability among localities with respect to lag phases (0-50 days) and some variation with respect to degradation periods (20-40 days); and (3) nitrobenzene, o-nitrophenol, 2,6-dichlorophenol and 4,6- o-dichlorocresol showed very large variability among localities ranging from no degradation within 149 days in some localities to degradation within 2 days in other localities. The degradation patterns were highly sequential, indicating a general sequence, for those compounds degradable, valid in all localities. The results are of importance in designing experimental determination of degradation rates and in assigning degradation parameters for use in solute transport models.

  18. A microbial functional group-based module for simulating methane production and consumption: Application to an incubated permafrost soil

    SciTech Connect

    Xu, Xiaofeng; Elias, Dwayne A.; Graham, David E.; Phelps, Tommy J.; Carroll, Sue L.; Wullschleger, Stan D.; Thornton, Peter E.

    2015-07-23

    In this study, accurately estimating methane (CH4) flux is critically important for investigating and predicting the biogeochemistry-climate feedback. Better simulating CH4 flux requires explicit representations of microbial processes on CH4 dynamics because all processes for CH4 production and consumption are actually carried out by microbes. A microbial functional group based module was developed and tested against an incubation experiment. The module considers four key mechanisms for CH4 production and consumption: methanogenesis from acetate or single-carbon compounds and CH4 oxidation using molecular oxygen or other inorganic electron acceptors. These four processes were carried out by four microbial functional groups: acetoclastic methanogens, hydrogenotrophic methanogens, aerobic methanotrophs, and anaerobic methanotrophs. This module was then linked with the decomposition subroutine of the Community Land Model, and was further used to simulate dynamics of carbon dioxide (CO2) and CH4 concentrations from an incubation experiment with permafrost soils. The results show that the model could capture the dynamics of CO2 and CH4 concentrations in microcosms with top soils, mineral layer soils and permafrost soils under natural and saturated moisture conditions and a temperature gradient of -2°C, 3°C, and 5°C. Sensitivity analysis confirmed the importance of acetic acid's direct contribution as substrate and indirect effects through pH feedback on CO2 and CH4 production and consumption. This study suggests that representing the microbial mechanisms is critical for modeling CH4 production and consumption; it is urgent to incorporate microbial mechanisms into Earth system models for better predicting the behavior of the climate system.

  19. A microbial functional group-based module for simulating methane production and consumption: Application to an incubated permafrost soil

    DOE PAGESBeta

    Xu, Xiaofeng; Elias, Dwayne A.; Graham, David E.; Phelps, Tommy J.; Carroll, Sue L.; Wullschleger, Stan D.; Thornton, Peter E.

    2015-07-23

    In this study, accurately estimating methane (CH4) flux is critically important for investigating and predicting the biogeochemistry-climate feedback. Better simulating CH4 flux requires explicit representations of microbial processes on CH4 dynamics because all processes for CH4 production and consumption are actually carried out by microbes. A microbial functional group based module was developed and tested against an incubation experiment. The module considers four key mechanisms for CH4 production and consumption: methanogenesis from acetate or single-carbon compounds and CH4 oxidation using molecular oxygen or other inorganic electron acceptors. These four processes were carried out by four microbial functional groups: acetoclastic methanogens,more » hydrogenotrophic methanogens, aerobic methanotrophs, and anaerobic methanotrophs. This module was then linked with the decomposition subroutine of the Community Land Model, and was further used to simulate dynamics of carbon dioxide (CO2) and CH4 concentrations from an incubation experiment with permafrost soils. The results show that the model could capture the dynamics of CO2 and CH4 concentrations in microcosms with top soils, mineral layer soils and permafrost soils under natural and saturated moisture conditions and a temperature gradient of -2°C, 3°C, and 5°C. Sensitivity analysis confirmed the importance of acetic acid's direct contribution as substrate and indirect effects through pH feedback on CO2 and CH4 production and consumption. This study suggests that representing the microbial mechanisms is critical for modeling CH4 production and consumption; it is urgent to incorporate microbial mechanisms into Earth system models for better predicting the behavior of the climate system.« less

  20. Low-Temperature Biochar Affects an Eroded Calcareous Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research showed little benefit from using a high temperature, high pH biochar for improving the fertility of eroded calcareous soils. We thus explored the potential of an activated, low-temperature, low pH biochar to improve their fertility status. In a microcosm study conducted at 20 de...

  1. Nitrate and the Origin of Saliva Influence Composition and Short Chain Fatty Acid Production of Oral Microcosms.

    PubMed

    Koopman, Jessica E; Buijs, Mark J; Brandt, Bernd W; Keijser, Bart J F; Crielaard, Wim; Zaura, Egija

    2016-08-01

    Nitrate is emerging as a possible health benefactor. Especially the microbial conversion of nitrate to nitrite in the oral cavity and the subsequent conversion to nitric oxide in the stomach are of interest in this regard. Yet, how nitrate influences the composition and biochemistry of the oral ecosystem is not fully understood. To investigate the effect of nitrate on oral ecology, we performed a 4-week experiment using the multiplaque artificial mouth (MAM) biofilm model. This model was inoculated with stimulated saliva of two healthy donors. Half of the microcosms (n = 4) received a constant supply of nitrate, while the other half functioned as control (n = 4). Additionally, all microcosms received a nitrate and sucrose pulse, each week, on separate days to measure nitrate reduction and acid formation. The bacterial composition of the microcosms was determined by 16S rDNA sequencing. The origin of the saliva (i.e., donor) showed to be the strongest determinant for the development of the microcosms. The supplementation of nitrate was related to a relatively high abundance of Neisseria in the microcosms of both donors, while Veillonella was highly abundant in the nitrate-supplemented microcosms of only one of the donors. The lactate concentration after sucrose addition was similarly high in all microcosms, irrespective of treatment or donor, while the concentration of butyrate was lower after nitrate addition in the nitrate-receiving microcosms. In conclusion, nitrate influences the composition and biochemistry of oral microcosms, although the result is strongly dependent on the inoculum. PMID:27155967

  2. Relative decay of fecal indicator bacteria and human-associated markers: a microcosm study simulating wastewater input into seawater and freshwater.

    PubMed

    Jeanneau, L; Solecki, O; Wéry, N; Jardé, E; Gourmelon, M; Communal, P-Y; Jadas-Hécart, A; Caprais, M-P; Gruau, G; Pourcher, A-M

    2012-02-21

    Fecal contaminations of inland and coastal waters induce risks to human health and economic losses. To improve water management, specific markers have been developed to differentiate between sources of contamination. This study investigates the relative decay of fecal indicator bacteria (FIB, Escherichia coli and enterococci) and six human-associated markers (two bacterial markers: Bacteroidales HF183 (HF183) and Bifidobacterium adolescentis (BifAd); one viral marker: genogroup II F-specific RNA bacteriophages (FRNAPH II); three chemical markers: caffeine and two fecal stanol ratios) in freshwater and seawater microcosms seeded with human wastewater. These experiments were performed in darkness, at 20 °C and under aerobic conditions. The modeling of the decay curves allows us (i) to compare FIB and markers and (ii) to classify markers according to their persistence in seawater (FRNAPH II < HF183, stanol ratios < BifAd, caffeine) and in freshwater (HF183, stanol ratios < FRNAPH II < BifAd < caffeine). Although those results depend on the experimental conditions, this study represents a necessary step to develop and validate an interdisciplinary toolbox for the investigation of the sources of fecal contaminations. PMID:22236067

  3. Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

    NASA Astrophysics Data System (ADS)

    Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

    2009-05-01

    SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not

  4. Phylogenetic and Kinetic Diversity of Aerobic Vinyl Chloride-Assimilating Bacteria from Contaminated Sites

    PubMed Central

    Coleman, Nicholas V.; Mattes, Timothy E.; Gossett, James M.; Spain, Jim C.

    2002-01-01

    Aerobic bacteria that grow on vinyl chloride (VC) have been isolated previously, but their diversity and distribution are largely unknown. It is also unclear whether such bacteria contribute to the natural attenuation of VC at chlorinated-ethene-contaminated sites. We detected aerobic VC biodegradation in 23 of 37 microcosms and enrichments inoculated with samples from various sites. Twelve different bacteria (11 Mycobacterium strains and 1 Nocardioides strain) capable of growth on VC as the sole carbon source were isolated, and 5 representative strains were examined further. All the isolates grew on ethene in addition to VC and contained VC-inducible ethene monooxygenase activity. The Mycobacterium strains (JS60, JS61, JS616, and JS617) all had similar growth yields (5.4 to 6.6 g of protein/mol), maximum specific growth rates (0.17 to 0.23 day−1), and maximum specific substrate utilization rates (9 to 16 nmol/min/mg of protein) with VC. The Nocardioides strain (JS614) had a higher growth yield (10.3 g of protein/mol), growth rate (0.71 day−1), and substrate utilization rate (43 nmol/min/mg of protein) with VC but was much more sensitive to VC starvation. Half-velocity constant (Ks) values for VC were between 0.5 and 3.2 μM, while Ks values for oxygen ranged from 0.03 to 0.3 mg/liter. Our results indicate that aerobic VC-degrading microorganisms (predominantly Mycobacterium strains) are widely distributed at sites contaminated with chlorinated solvents and are likely to be responsible for the natural attenuation of VC. PMID:12450841

  5. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  6. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  7. 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…

  8. DETERMINATION OF TRANSFORMATION RATES OF CHIRAL PESTICIDES AND PCBS IN SOIL AND SEDIMENT MICROCOSMS

    EPA Science Inventory

    Risk Based Corrective Action (RBCA) has gained widespread acceptance as a favorable approach to remediating contaminated sites. The use of RBCA methods often requires computer-based modeling to assess the fate and transport of hazardous contaminants in subsurface environments, a...

  9. A simple, inexpensive, and field-relevant microcosm tidal simulator for use in marsh macrophyte studies1

    PubMed Central

    MacTavish, Rachel M.; Cohen, Risa A.

    2014-01-01

    • Premise of the study: A microcosm unit with tidal simulation was developed to address the challenge of maintaining ecologically relevant tidal regimes while performing controlled greenhouse experiments on smooth cordgrass, Spartina alterniflora. • Methods and Results: We designed a simple, inexpensive, easily replicated microcosm unit with tidal simulation and tested whether S. alterniflora growth in microcosms with tidal simulation was similar to that of tidally influenced plants in the field on Sapelo Island, Georgia. After three months of exposure to either natural or simulated tidal treatment, plants in microcosms receiving tidal simulation had similar stem density, height, and above- and belowground biomass to plants in field plots. • Conclusions: The tidal simulator developed may provide an inexpensive, effective method for conducting studies on S. alterniflora and other tidally influenced plants in controlled settings to be used not only to complement field studies, but also in locations without coastal access. PMID:25383265

  10. Extraction of microbial proteome from soil: potential and limitations assessed through a model study

    SciTech Connect

    Giagnoni, L.; van der Lelie, D.; Magherini, F.; Landi, L.; Taghavi, S.; Modesti, A.; Bini, L.; Nannipieri, P.; Renella, G.

    2011-02-01

    Proteomics is the study of functions and regulation of biological systems based on the analysis of the protein expression profile, and there is a general agreement that soil proteomics may be a tool for better soil management. Because of the ability of soils to stabilize extracellular proteins by various mechanisms, development of soil proteomics needs an assessment of the efficiency of protein extraction from various soil types. We evaluated the possibility of extraction of soil microbial proteome by inoculating Cupriavidus metallidurans CH34, which has a known proteome, into sterile sand, kaolinite, montmorillonite and a mixture of sand, kaolinite, montmorillonite, goethite and humic acids. One hour after inoculation, the viability of C. metallidurans was determined by the colony-forming units method (CFU), the amount of extracted proteins was determined by the Bradford method and the bacterial proteome was analysed by the two-dimensional gel electrophoresis technique (2D-GE). The bacterial number was 2.5 x 10{sup 6} CFU g{sup -1} of soil in all microcosms, whereas the total extracted protein content varied from 98.1 to 1268 {micro}g g{sup -1} in the various microcosms, but was undetectable in the inoculated montmorillonite. The number of protein spots from the bacterial culture and the inoculated microcosms varied between 317 and 591, with 54 variable spots among the pure culture and the microcosms. No protein spots were detected in the 2D-GE from the montmorillonite microcosm. The 2D-GE of artificial soil microcosms showed a protein pattern that was different from those of pure culture and sand and kaolinite microcosms. The results confirm the importance of clay-specific surface area and CEC in protein adsorption as montmorillonite alone had the largest sorptive capacity, and show that the artificial soil used also had a large sorptive capacity for microbial proteins. Globally, the results indicate that the extraction of proteins from soils is strongly

  11. Survival study of enterotoxigenic Escherichia colistrain in seawater and wastewater microcosms.

    PubMed

    Boukef Ben Omrane, I; El Bour, M; Mejri, S; Mraouna, R; Got, P; Troussellier, M; Boudabous, A

    2011-01-01

    In order to survey osmotic and oligotrophic stress consequence on pathogenic enterobacteria discharged in marine areas, we examined enterotoxigenic Escherichia coli (ETEC) and a reference (Ecoli O126:B16) strains during their survival (47 days) in wastewater microcosms, submerged in natural seawater and maintained in laboratory conditions. The results revealed that the survival time for the two strains was prolonged when bacterial cells were previously incubated in wastewater, with less cellular membrane damage. In addition, the wild clinical E. coli strain showed a better survival capacity than the reference E. coli strain one. For both, we noted some modifications in biochemical profiles relatively to the initial state, notably when they were previously incubated in wastewater microcosm. PMID:23461140

  12. Comparative assessment of fungal augmentation treatments of a fine-textured and historically oil-contaminated soil.

    PubMed

    Covino, Stefano; Stella, Tatiana; D'Annibale, Alessandro; Lladó, Salvador; Baldrian, Petr; Čvančarová, Monika; Cajthaml, Tomas; Petruccioli, Maurizio

    2016-10-01

    The removal of aged hydrophobic contaminants from fine-textured soils is a challenging issue in remediation. The objective of this study was to compare the efficacy of augmentation treatments to that of biostimulation in terms of total aliphatic hydrocarbon (TAH) and toxicity removal from a historically contaminated clay soil and to assess their impact on the resident microbial community. To this aim, Pleurotus ostreatus, Botryosphaeria rhodina and a combination of both were used as the inoculants while the addition of a sterilized lignocellulose mixture to soil (1:5, w/w) was used as a biostimulation approach. As opposed to the non-amended control soil, where no changes in TAH concentration and residual toxicity were observed after 60days, the activation of specialized bacteria was found in the biostimulated microcosms resulting in significant TAH removal (79.8%). The bacterial community structure in B. rhodina-augmented microcosms did not differ from the biostimulated microcosms due to the inability of the fungus to be retained within the resident microbiota. Best TAH removals were observed in microcosms inoculated with P. ostreatus alone (Po) and in binary consortium with B. rhodina (BC) (86.8 and 88.2%, respectively). In these microcosms, contaminant degradation exceeded their bioavailability thresholds determined by sequential supercritical CO2 extraction. Illumina metabarcoding of 16S rRNA gene showed that the augmentation with Po and BC led to lower relative abundances of Gram(+) taxa, Actinobacteria in particular, than those in biostimulated microcosms. Best detoxification, with respect to the non-amended incubation control, was found in Po microcosms where a drop in collembola mortality (from 90 to 22%) occurred. At the end of incubation, in both Po and BC, the relative abundances of P. ostreatus sequences were higher than 60% thus showing the suitability of this fungus in bioaugmentation-based remediation applications. PMID:27220102

  13. Comparing the impacts of sediment-bound bifenthrin on aquatic macroinvertebrates in laboratory bioassays and field microcosms.

    PubMed

    Boyle, Rhianna L; Hoak, Molly N; Pettigrove, Vincent J; Hoffmann, Ary A; Long, Sara M

    2016-11-01

    We conducted two laboratory bioassays and two field microcosm exposures with bifenthrin (a synthetic pyrethroid) in order to evaluate the capacity of single-species laboratory bioassays to predict lethal and sublethal impacts on aquatic invertebrates in microcosms. For the laboratory species, Chironomus tepperi, larval survival was reduced by 24% at 53.66µg/g OC, while adult emergence was reduced at concentrations of 33.33µg/g OC and higher, with a 61% decrease at 77.78µg/g OC and no emergence at 126.67µg/g OC. The abundance of several other microcosm taxa was reduced in the microcosms at a similar concentration range (33.33µg/g OC and above), however there was no impact on the abundance of the congeneric species, Chironomus oppositus. The differences in impacts between test systems were potentially due to both differing species sensitivity and the interaction of ambient temperature with bifenthrin toxicity. Bifenthrin also was associated with early emergence of Chironomus sp. in both test systems, at concentrations of 10µg/g OC and higher (laboratory) and 43.90µg/g OC (microcosm), and with a significant decrease in the proportion of C. oppositus males in a microcosm. These findings indicate that while laboratory bioassays accurately predict many impacts in the field, there are some limitations to the predictive capacity of these tests. PMID:27544659

  14. Fit women are not able to use the whole aerobic capacity during aerobic dance.

    PubMed

    Edvardsen, Elisabeth; Ingjer, Frank; Bø, Kari

    2011-12-01

    Edvardsen, E, Ingjer, F, and Bø, K. Fit women are not able to use the whole aerobic capacity during aerobic dance. J Strength Cond Res 25(12): 3479-3485, 2011-This study compared the aerobic capacity during maximal aerobic dance and treadmill running in fit women. Thirteen well-trained female aerobic dance instructors aged 30 ± 8.17 years (mean ± SD) exercised to exhaustion by running on a treadmill for measurement of maximal oxygen uptake (VO(2)max) and peak heart rate (HRpeak). Additionally, all subjects performed aerobic dancing until exhaustion after a choreographed videotaped routine trying to reach the same HRpeak as during maximal running. The p value for statistical significance between running and aerobic dance was set to ≤0.05. The results (mean ± SD) showed a lower VO(2)max in aerobic dance (52.2 ± 4.02 ml·kg·min) compared with treadmill running (55.9 ± 5.03 ml·kg·min) (p = 0.0003). Further, the mean ± SD HRpeak was 182 ± 9.15 b·min in aerobic dance and 192 ± 9.62 b·min in treadmill running, giving no difference in oxygen pulse between the 2 exercise forms (p = 0.32). There was no difference in peak ventilation (aerobic dance: 108 ± 10.81 L·min vs. running: 113 ± 11.49 L·min). In conclusion, aerobic dance does not seem to be able to use the whole aerobic capacity as in running. For well endurance-trained women, this may result in a lower total workload at maximal intensities. Aerobic dance may therefore not be as suitable as running during maximal intensities in well-trained females. PMID:22080322

  15. Survival and impact of genetically engineered Pseudomonas putida harboring mercury resistance gene in aquatic microcosms.

    PubMed

    Iwasaki, K; Uchiyama, H; Yagi, O

    1993-08-01

    The survival of wild-type and genetically engineered Pseudomonas putida PpY101 that contained a recombinant plasmid pSR134 conferring mercury resistance were monitored in aquatic microcosms. We used lake, river, and spring water samples. The density of genetically engineered and wild-type P. putida decreased rapidly within 5 days (population change rate k -0.87 approximately -1.00 day-1), then moderately after 5 to 28 days (-0.10 approximately -0.14 day-1). The population change rates of genetically engineered and wild-type P. putida were not significantly different. We studied the important factors affecting the survival of genetically engineered and wild-type P. putida introduced in aquatic microcosms. Visible light exerted an adverse effect on the survival of the two strains. The densities of genetically engineered and wild-type P. putida were almost constant until 7 days after inoculation in natural water filtered with a 0.45-micron membrane filter, or treated with cycloheximide to inhibit the growth of protozoa. These results suggested that protozoan predation was one of the most important factors for the survival of two strains. We examined the impact of the addition of genetically engineered and wild-type P. putida on indigenous bacteria and protozoa. Inoculation of genetically engineered or wild-type P. putida had no apparent effect on the density of indigenous bacteria. The density of protozoa increased in microcosms inoculated with genetically engineered or wild-type P. putida at 3 days after inoculation, but after 5 to 21 days, the density of protozoa decreased to the same level as the control microcosms. PMID:7764012

  16. Mercury Distribution, Methylation and Volatilization in Microcosms with and without the Sea Anemone Bunodosoma caissarum

    NASA Astrophysics Data System (ADS)

    Ansari, N. R.; Correia, R. R. S.; Fernandez, M. A. S.; Cordeiro, R. C.; Guimarães, J. R. D.

    2014-12-01

    Mercury (Hg) can be a dangerous contaminant and has a complex biogeochemical cycling in aquatic environments. The sea anemone Bunodosoma caissarum is an endemic species in Brazil capable of bioaccumulating Hg from the ambient seawater. The radiotracer 203Hg was used in order to investigate mechanisms of Hg uptake and depuration of B. caissarum and the distribution of Hg in laboratory model systems, with and without B. caissarum. A single initial spike of 203Hg was added to each microcosm. Microcosms had continuous air renovation and trapping of Hg volatile forms. Total Hg in different compartments was measured by gamma spectrometry. In the uptake experiment 203Hg activity was determined periodically in seawater and specimens for 6 days. At the end, specimens had an average bioconcentration factor of 70. After the uptake experiment, methylmercury (MeHg) in seawater was extracted and measured by liquid scintillation. In microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. Hg was probably less available for methylation in the first because of bioaccumulation and higher concentrations of suspended particulate matter that could form complexes with Hg. After that, specimens were transferred to unspiked microcosms. After a 48 day depuration specimens still retained 35 - 70% of the previously bioaccumulated Hg and 0.2 - 2.4% of the total Hg was MeHg. The presence of B. caissarum resulted in an unexpected higher volatilization of Hg (58%) compared to controls (17%). This increased volatilization is possibly a result of Hg2+ reduction mediated by microorganisms associated with its tissues and mucus secretions and/or an unknown defense mechanism of this species.

  17. Polychlorinated biphenyl (PCB) anaerobic degradation in marine sediments: microcosm study and role of autochthonous microbial communities.

    PubMed

    Matturro, Bruna; Ubaldi, Carla; Grenni, Paola; Caracciolo, Anna Barra; Rossetti, Simona

    2016-07-01

    Polychlorobiphenyl (PCB) biodegradation was followed for 1 year in microcosms containing marine sediments collected from Mar Piccolo (Taranto, Italy) chronically contaminated by this class of hazardous compounds. The microcosms were performed under strictly anaerobic conditions with or without the addition of Dehalococcoides mccartyi, the main microorganism known to degrade PCBs through the anaerobic reductive dechlorination process. Thirty PCB congeners were monitored during the experiments revealing that the biodegradation occurred in all microcosms with a decrease in hepta-, hexa-, and penta-chlorobiphenyls (CBs) and a parallel increase in low chlorinated PCBs (tri-CBs and tetra-CBs). The concentrations of the most representative congeners detected in the original sediment, such as 245-245-CB and 2345-245-CB, and of the mixture 2356-34-CB+234-245-CB, decreased by 32.5, 23.8, and 46.7 %, respectively, after only 70 days of anaerobic incubation without any bioaugmentation treatment. Additionally, the structure and population dynamics of the microbial key players involved in the biodegradative process and of the entire mixed microbial community were accurately defined by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) in both the original sediment and during the operation of the microcosm. The reductive dehalogenase genes of D. mccartyi, specifically involved in PCB dechlorination, were also quantified using real-time PCR (qPCR). Our results demonstrated that the autochthonous microbial community living in the marine sediment, including D. mccartyi (6.32E+06 16S rRNA gene copy numbers g(-1) sediment), was able to efficiently sustain the biodegradation of PCBs when controlled anaerobic conditions were imposed. PMID:26162439

  18. Modelling algae-duckweed interaction under chemical pressure within a laboratory microcosm.

    PubMed

    Lamonica, Dominique; Clément, Bernard; Charles, Sandrine; Lopes, Christelle

    2016-06-01

    Contaminant effects on species are generally assessed with single-species bioassays. As a consequence, interactions between species that occur in ecosystems are not taken into account. To investigate the effects of contaminants on interacting species dynamics, our study describes the functioning of a 2-L laboratory microcosm with two species, the duckweed Lemna minor and the microalgae Pseudokirchneriella subcapitata, exposed to cadmium contamination. We modelled the dynamics of both species and their interactions using a mechanistic model based on coupled ordinary differential equations. The main processes occurring in this two-species microcosm were thus formalised, including growth and settling of algae, growth of duckweeds, interspecific competition between the two species and cadmium effects. We estimated model parameters by Bayesian inference, using simultaneously all the data issued from multiple laboratory experiments specifically conducted for this study. Cadmium concentrations ranged between 0 and 50 μg·L(-1). For all parameters of our model, we obtained biologically realistic values and reasonable uncertainties. Only duckweed dynamics was affected by interspecific competition, while algal dynamics was not impaired. Growth rate of both species decreased with cadmium concentration, as well as competition intensity showing that the interspecific competition pressure on duckweed decreased with cadmium concentration. This innovative combination of mechanistic modelling and model-guided experiments was successful to understand the algae-duckweed microcosm functioning without and with contaminant. This approach appears promising to include interactions between species when studying contaminant effects on ecosystem functioning. PMID:26922150

  19. Magnetotactic bacteria in microcosms originating from the French Mediterranean Coast subjected to oil industry activities.

    PubMed

    Postec, Anne; Tapia, Nicolas; Bernadac, Alain; Joseph, Manon; Davidson, Sylvain; Wu, Long-Fei; Ollivier, Bernard; Pradel, Nathalie

    2012-01-01

    Magnetotactic bacteria (MTB) mineralize nanosized magnetite or greigite crystals within cells and thus play an important role in the biogeochemical process. Despite decades of research, knowledge of MTB distribution and ecology, notably in areas subjected to oil industry activities, is still limited. In the present study, we investigated the presence of MTB in the Gulf of Fos, French Mediterranean coast, which is subjected to intensive oil industry activities. Microcosms containing sediments/water (1:2, v/v) from several sampling sites were monitored over several weeks. The presence of MTB was revealed in five of eight sites. Diverse and numerous MTB were revealed particularly from one site (named CAR), whilst temporal variations of a homogenous magnetotactic cocci population was shown within the LAV site microcosm over a 4-month period. Phylogenetic analysis revealed that they belonged to Alphaproteobacteria, and a novel genus from the LAV site was evidenced. Among the physicochemical parameters measured, a correlation was shown between the variation of MTB abundance in microcosms and the redox state of sulphur compounds. PMID:21766218

  20. Glyceria maxima as new test species for the EU risk assessment for herbicides: a microcosm study.

    PubMed

    Mohr, S; Schott, J; Hoenemann, L; Feibicke, M

    2015-03-01

    In its recent guidance document on tiered risk assessment for plant protection products for aquatic organisms, the European Food Safety Authority (EFSA) proposed to use Glyceria maxima as monocotyledonous grass species for the testing of special herbicide groups. However, published toxicity data for this species is very limited and there is no test guideline for Glyceria sp. For this reason a microcosm study was conducted in order to gain experience on the degree of sensitivity of G. maxima to the herbicidal substances clodinafop-propargyl (grass herbicide) and fluroxypyr (auxin) in comparison to the already established test organism water milfoil Myriophyllum spicatum and the duckweed species Landoltia punctata. Five concentrations without replicates were tested for each test substance using 10 microcosms and three microcosms served as controls. The experiment was run for 8 weeks. Morphological endpoints were used to determine growth and EC50 values. The results show that M. spicatum was most sensitive to fluroxypyr (37 days EC50 for roots: 62 µg/L) and G. maxima most sensitive to clodinafop-propargyl (22 days EC50 for total shoot length: 48 µg/L) whereas the duckweed species was considerable less sensitive. Hence, G. maxima turns out to be a good candidate for testing grass specific herbicides, supporting its inclusion as an additional macrophyte test for the risk assessment of herbicides as proposed by the EFSA. PMID:25380672

  1. Microbial abundance and community in subsurface flow constructed wetland microcosms: role of plant presence.

    PubMed

    Wang, Qian; Xie, Huijun; Ngo, Huu Hao; Guo, Wenshan; Zhang, Jian; Liu, Cui; Liang, Shuang; Hu, Zhen; Yang, Zhongchen; Zhao, Congcong

    2016-03-01

    In this research, the role of plants in improving microorganism growth conditions in subsurface flow constructed wetland (CW) microcosms was determined. In particular, microbial abundance and community were investigated during summer and winter in Phragmites australis-planted CW microcosms (PA) and unplanted CW microcosms (control, CT). Results revealed that the removal efficiencies of pollutants and microbial community structure varied in winter with variable microbial abundance. During summer, PA comprised more dominant phyla (e.g., Proteobacteria, Actinobacteria, and Bacteroidetes), whereas CT contained more Cyanobacteria and photosynthetic bacteria. During winter, the abundance of Proteobacteria was >40 % in PA but dramatically decreased in CT. Moreover, Cyanobacteria and photosynthetic bacterial dominance in CT decreased. In both seasons, bacteria were more abundant in root surfaces than in sand. Plant presence positively affected microbial abundance and community. The potential removal ability of CT, in which Cyanobacteria and photosynthetic bacteria were abundant during summer, was more significantly affected by temperature reduction than that of PA with plant presence. PMID:25772872

  2. Mercury distribution, methylation and volatilization in microcosms with and without the sea anemone Bunodosoma caissarum.

    PubMed

    Rizzini Ansari, Nafisa; Correia, Raquel Rose Silva; Fernandez, Marcos Antônio; Cordeiro, Renato Campello; Guimarães, Jean Remy Davée

    2015-03-15

    Mercury (Hg) has a complex biogeochemical cycle in aquatic environments. Its most toxic form, methylmercury (MeHg), is produced by microorganisms. This study investigated how the sea anemone Bunodosoma caissarum affects Hg distribution, methylation and volatilization in laboratory model systems. (203)Hg was added to microcosms and its distribution in seawater, specimens and air was periodically measured by gamma spectrometry. MeHg was measured by liquid scintillation. After the uptake period, specimens had a bioconcentration factor of 70 and in microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. After depuration, MeHg in specimens ranged from 0.2% to 2.4% of total Hg. Microcosms with B. caissarum had higher Hg volatilization (58%) than controls (17%), possibly due to Hg(2+) reduction mediated by microorganisms associated with its tissues and mucus secretions. Marine organisms and their associated microbiota may play a role in Hg and MeHg cycling. PMID:25599628

  3. Emissions of NO and N2O in wetland microcosms for swine wastewater treatment.

    PubMed

    Zhang, Shunan; Liu, Feng; Xiao, Runlin; Li, Yong; Zhou, Juan; Wu, Jinshui

    2015-12-01

    Nitric oxide (NO) and nitrous oxide (N2O) emitted from wetland systems contribute an important proportion to the global warming effect. In this study, four wetland microcosms vegetated with Myriophyllum elatinoides (WM), Alternanthera philoxeroides (WA), Eichhornia crassipes (WE), or without vegetation (NW) were compared to investigate the emissions of NO and N2O during nitrogen (N) removal process when treating swine wastewater. After 30-day incubation, TN removal rates of 96.4, 74.2, 97.2, and 47.3 % were observed for the WM, WA, WE, and NW microcosms, respectively. Yet, no significant difference was observed in WM and WE (p > 0.05). The average NO and N2O emissions in WE was significantly higher than those in WM, WA, and NW (p < 0.05). In addition, the emission of N2O in WE accounted for 2.10 % of initial TN load and 2.17 % of the total amount of TN removal, compared with less than 1 % in the other microcosms. These findings indicate that wetland vegetated with M. elatinoides may be an optimal system for swine wastewater treatment, based on its higher removal of N and lower emissions of NO and N2O. PMID:26289333

  4. Enhanced and Stabilized Arsenic Retention in Microcosms through the Microbial Oxidation of Ferrous Iron by Nitrate

    PubMed Central

    SUN, JING; CHILLRUD, STEVEN N.; MAILLOUX, BRIAN J.; STUTE, MARTIN; SINGH, RAJESH; DONG, HAILIANG; LEPRE, CHRISTOPHER J.; BOSTICK, BENJAMIN C.

    2016-01-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II)(aq)(as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II)(aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6 – 7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  5. Microcosm for assessing survival of genetically engineered microorganisms in aquatic environments.

    PubMed Central

    Awong, J; Bitton, G; Chaudhry, G R

    1990-01-01

    Laboratory-contained microcosms are important for studying the fate and survival of genetically engineered microorganisms. In this study, we describe a simple aquatic microcosm that utilizes survival chambers in a flowthrough or static renewal system. The model was used to study the survival of genetically engineered and wild-type strains of Escherichia coli and Pseudomonas putida in the lake water environment. Temperature-dependent studies indicated that the genetically engineered microorganisms survived better or at least as well as their wild-type counterparts at 15, 25, and 30 degrees C. The genetic determinants of the genetically engineered microorganisms also remained fairly stable within the host cell under the tested conditions. In the presence of organisms indigenous to lake water, E. coli was eliminated after 20 days, whereas P. putida showed an initial decline but was able to stabilize its population after 5 days. A herbicide, Hydrothol-191, caused a significant decline in numbers of P. putida, but no significant difference was observed between the genetically engineered microorganisms and the wild-type strain. The microcosm described is simple, can be easily adapted to study a variety of environmental variables, and has the advantage that the organisms tested are constantly exposed to test waters that are continuously renewed. PMID:2187407

  6. Enhanced and stabilized arsenic retention in microcosms through the microbial oxidation of ferrous iron by nitrate.

    PubMed

    Sun, Jing; Chillrud, Steven N; Mailloux, Brian J; Stute, Martin; Singh, Rajesh; Dong, Hailiang; Lepre, Christopher J; Bostick, Benjamin C

    2016-02-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II) (aq) (as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II) (aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6-7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  7. Microbial Characterization of Biofilms in Domestic Drains and the Establishment of Stable Biofilm Microcosms

    PubMed Central

    McBain, Andrew J.; Bartolo, Robert G.; Catrenich, Carl E.; Charbonneau, Duane; Ledder, Ruth G.; Rickard, Alexander H.; Symmons, Sharon A.; Gilbert, Peter

    2003-01-01

    We have used heterotrophic plate counts, together with live-dead direct staining and denaturing gradient gel electrophoresis (DGGE), to characterize the eubacterial communities that had formed as biofilms within domestic sink drain outlets. Laboratory microcosms of these environments were established using excised biofilms from two separate drain biofilm samples to inoculate constant-depth film fermentors (CDFFs). Drain biofilms harbored 9.8 to 11.3 log10 cells of viable enteric species and pseudomonads/g, while CDFF-grown biofilms harbored 10.6 to 11.4 log10 cells/g. Since live-dead direct staining revealed various efficiencies of recovery by culture, samples were analyzed by DGGE, utilizing primers specific for the V2-V3 region of eubacterial 16S rDNA. These analyses showed that the major PCR amplicons from in situ material were represented in the microcosms and maintained there over extended periods. Sequencing of amplicons resolved by DGGE revealed that the biofilms were dominated by a small number of genera, which were also isolated by culture. One drain sample harbored the protozoan Colpoda maupasi, together with rhabtidid nematodes and bdelloid rotifers. The microcosm enables the maintenance of stable drain-type bacterial communities and represents a useful tool for the modeling of this ecosystem. PMID:12513993

  8. Microcosm for assessing survival of genetically engineered microorganisms in aquatic environments

    SciTech Connect

    Awong, J.; Bitton, G.; Chaudhry, G.R. )

    1990-04-01

    Laboratory-contained microcosms are important for studying the fate and survival of genetically engineered microorganisms. In this study, we describe a simple aquatic microcosm that utilizes survival chambers in a flow through or static renewal system. The model was used to study the survival of genetically engineered and wild-type strains of Escherichia coli and Pseudomonas putida in the lake water environment. Temperature-dependent studies indicated that the genetically engineered microorganisms survived better or at least as well as their wild-type counterparts at 15, 25, and 30{degree}C. The genetic determinants of the genetically engineered microorganisms also remained fairly stable within the host cell under the tested conditions. In the presence of organisms indigenous to lake water, E. coli was eliminated after 20 days, whereas P. putida showed an initial decline but was able to stabilize its population after 5 days. A herbicide, Hydrothol-191, caused a significant decline in numbers of P. putida, but no significant difference was observed between the genetically engineered microorganisms and the wild-type strain. The microcosm described is simple, can be easily adapted to study a variety of environmental variables, and has the advantage that the organisms tested are constantly exposed to test waters that are continuously renewed.

  9. Impact of Roundup on the marine microbial community, as shown by an in situ microcosm experiment.

    PubMed

    Stachowski-Haberkorn, Sabine; Becker, Beatriz; Marie, Dominique; Haberkorn, Hansy; Coroller, Louis; de la Broise, Denis

    2008-09-29

    The effects of the herbicide Roundup (glyphosate) on natural marine microbial communities were assessed in a 7-day field experiment using microcosms. Bottles were maintained underwater at 6m depth, and 10% of their water content was changed every other day. The comparison of control microcosms and surrounding surface water showed that the microcosm system tested here can be considered as representative of the natural surrounding environment. A temporal temperature gradient gel electrophoresis (TTGE) was run on 16S and 18S rDNA-amplified extracts from the whole microbial community. Cluster analysis of the 16S gel showed differences between control and treatment fingerprints for Roundup at 1 microg L(-1) (ANOSIM, p=0.055; R=0.53), and 10 microg L(-1) (ANOSIM, p=0.086; R=0.40). Flow cytometry analysis revealed a significant increase in the prasinophyte-like population when Roundup concentration was increased to 10 microg L(-1). This study demonstrates that a disturbance was caused to the marine microbial community exposed to 1 microg L(-1) Roundup concentration, a value typical of those reported in coastal waters during a run-off event. PMID:18760491

  10. Gonadal development of larval male Xenopus laevis exposed to atrazine in outdoor microcosms

    USGS Publications Warehouse

    Jooste, A.M.; Du Preez, L.H.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Solomon, K.R.

    2005-01-01

    The potential effects of atrazine on gonadal development in metamorphs and subadults of the African clawed frog (Xenopus laevis) were studied under conditions of natural photoperiod and temperatures in outdoor microcosms from August 2002 to June 2003 in South Africa. Triplicate 1100 L microcosms for each nominal concentration of 0.0, 1, 10, and 25 ??g of atrazine/L were used. Measured atrazine concentrations varied <25% throughout the study, and no atrazine was detected in the control microcosms. Tadpoles developed well at all concentrations. On the basis of histological examination of testes of recently metamorphosed stage 66 frogs, 57% of the individuals in the reference group exhibited testicular oocytes as compared with 57, 59, and 39% of the 1, 10, and 25 ??g/L atrazine groups, respectively. The average prevalence of testicular oocytes for all of the treatments including the controls was 54% in a single testis, while, in 35% of individuals, testicular oocytes were observed in both testes. The number of testicular oocytes per individual ranged from 0 to 58 with means of 9.5, 9.8, 8.5, and 11.1 for the 0.0, 1, 10, and 25 ??g of atrazine/L groups, respectively. Ten months after metamorphosis, another subset of juveniles was examined, and the maximum number of testicular oocytes observed was five in one animal. The presence of testicular oocytes was not related to exposure to atrazine and may be a natural phenomenon during ontogeny. ?? 2005 American Chemical Society.

  11. The use of outdoor freshwater pond microcosms. III. Responses of phytoplankton and periphyton to pyridaben

    USGS Publications Warehouse

    Ross, R.M.; Krise, W.F.; Redell, L.A.; Bennett, R.M.

    2001-01-01

    An outdoor freshwater microcosm study was conducted in which pyridaben, an insecticide-miticide, was directly applied to water to determine its biological effects on phytoplankton and periphyton. Twenty-four microcosms (24 m3 each) were monitored for 11 months, then four treatments of pyridaben were applied two times at three concentrations (0.34, 34.0 ??g/L), including an untreated control. The succession of algal groups observed and the major genera found in microcosms during the baseline phase of the study were typical of oligo-mesotrophic systems in Florida. Following application of pyridaben, the most remarkable effect was a positive correlation of phytoplankton abundance with pyridaben concentrations in water; indicating increased abundance as a result of exposure. Both Chlorophyta and Pyrrophyta exhibited a significant increase (p=0.05) in population abundance at 3.4 and 34.0 ??g/L pyridaben. Chrysophyta also elicited a trend of increased abundance at 34.0 ??g/L, although the effect was not significant. The effects on phytoplankton populations were associated with the decline of zooplankton populations as a result of a direct effect of pyridaben exposure. There were no effects of pyridaben on periphyton communities or on functional endpoints. ?? 2001 by John Wiley & Sons, Inc.

  12. Role of arthropods in developing soils on mine spoils. Final report

    SciTech Connect

    Whitford, W.G.; Elkins, N.Z.; Parker, L.W.

    1981-06-01

    In laboratory microcosms of coal mine spoil amended with bark and wood chips, the activity of termites increased organic matter and increased total nitrogen. Termite survival was reduced in microcosms with spoil and paper or straw amendments. Field studies evaluating the efficacy of organic amendments in developing a soil biota showed that decomposition rates of wood chip-bark amended spoil were the same as unmined soil and that decomposition rates were lower than all other mulch-spoil combinations. Wood and bark amended-spoil had the highest density and diversity of soil fauna. Top dressing spoils with borrow soil did not improve any of the soil biological parameters measured. Based on these data it was recommended that reclamation procedures be changed to eliminate borrow soil top-dressing and that wood removed from mined areas be returned to the contoured spoil as wood chip amendment in addition to straw mulch.

  13. Population dynamics of transgenic strain Escherichia coli Z905/pPHL7 in freshwater and saline lake water microcosms with differing microbial community structures

    NASA Technical Reports Server (NTRS)

    Popova, L. Yu; Kargatova, T. V.; Ganusova, E. E.; Lobova, T. I.; Boyandin, A. N.; Mogilnaya, O. A.; Pechurkin, N. S.

    2005-01-01

    Populations of Escherichia coli Z905/pPHL7, a transgenic microorganism, were heterogenic in the expression of plasmid genes when adapting to the conditions of water microcosms of various mineralization levels and structure of microbial community. This TM has formed two subpopulations (ampicillin-resistant and ampicillin-sensitive) in every microcosm. Irrespective of mineralization level of a microcosm, when E. coli Z905/pPHL7 alone was introduced, the ampicillin-resistant subpopulation prevailed, while introduction of the TM together with indigenous bacteria led to the dominance of the ampicillin-sensitive subpopulation. A high level of lux gene expression maintained longer in the freshwater microcosms than in sterile saline lake water microcosms. A horizontal gene transfer has been revealed between the jointly introduced TM and Micrococcus sp. 9/pSH1 in microcosms with the Lake Shira sterile water. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

  14. Population dynamics of transgenic strain Escherichia coli Z905/pPHL7 in freshwater and saline lake water microcosms with differing microbial community structures

    NASA Astrophysics Data System (ADS)

    Popova, L. Yu.; Kargatova, T. V.; Ganusova, E. E.; Lobova, T. I.; Boyandin, A. N.; Mogilnaya, O. A.; Pechurkin, N. S.

    Populations of Escherichia coli Z905/pPHL7, a transgenic microorganism, were heterogenic in the expression of plasmid genes when adapting to the conditions of water microcosms of various mineralization levels and structure of microbial community. This TM has formed two subpopulations (ampicillin-resistant and ampicillin-sensitive) in every microcosm. Irrespective of mineralization level of a microcosm, when E. coli Z905/pPHL7 alone was introduced, the ampicillin-resistant subpopulation prevailed, while introduction of the TM together with indigenous bacteria led to the dominance of the ampicillin-sensitive subpopulation. A high level of lux gene expression maintained longer in the freshwater microcosms than in sterile saline lake water microcosms. A horizontal gene transfer has been revealed between the jointly introduced TM and Micrococcus sp. 9/pSH1 in microcosms with the Lake Shira sterile water.

  15. Occurrence and Fate of Trace Contaminants during Aerobic and Anaerobic Sludge Digestion and Dewatering.

    PubMed

    Guerra, Paula; Kleywegt, Sonya; Payne, Michael; Svoboda, M Lewina; Lee, Hing-Biu; Reiner, Eric; Kolic, Terry; Metcalfe, Chris; Smyth, Shirley Anne

    2015-07-01

    Digestion of municipal wastewater biosolids is a necessary prerequisite to their beneficial use in land application, in order to protect public health and the receiving environment. In this study, 13 pharmaceuticals and personal care products (PPCPs), 11 musks, and 17 polybrominated diphenyl ethers were analyzed in 84 samples including primary sludge, waste activated sludge, digested biosolids, dewatered biosolids, and dewatering centrate or filtrate collected from five wastewater treatment plants with aerobic or anaerobic digestion. Aerobic digestion processes were sampled during both warm and cold temperatures to analyze seasonal differences. Among the studied compounds, triclosan, triclocarban, galaxolide, and BDE-209 were the substances most frequently detected under different treatment processes at levels up to 30,000 ng/g dry weight. Comparing aerobic and anaerobic digestion, it was observed that the levels of certain PPCPs and musks were significantly higher in anaerobically digested biosolids, relative to the residues from aerobic digestion. Therefore, aerobic digestion has the potential advantage of reducing levels of PPCPs and musks. On the other hand, anaerobic digestion has the advantage of recovering energy from the biosolids in the form of combustible gases while retaining the nutrient and soil conditioning value of this resource. PMID:26437100

  16. Microcosm evaluation of autochthonous bioaugmentation to combat marine oil spills.

    PubMed

    Nikolopoulou, Maria; Eickenbusch, P; Pasadakis, Nikos; Venieri, Danae; Kalogerakis, Nicolas

    2013-09-25

    Oil spills can be disastrous to any ecosystem. Bioremediation through bioaugmentation (addition of oil-degrading bacteria) and biostimulation (addition of nutrients N&P) options can be a promising strategy for combating oil spills following first response actions. However, bioaugmentation is one of the most controversial issues of bioremediation since nutrient addition alone has a greater effect on oil biodegradation than the addition of microbial products that are highly dependent on environmental conditions. There is increasing evidence that the best way to overcome the above barriers is to use microorganisms from the polluted area, an approach proposed as autochthonous bioaugmentation (ABA) and defined as the bioaugmentation technology that uses exclusively microorganisms indigenous to the sites (soil, sand, and water) to be decontaminated. In this study, we examined the effectiveness of an ABA strategy for the successful remediation of polluted marine environments. A consortium was enriched from seawater samples taken from Elefsina Gulf near the Hellenic Petroleum Refinery, a site exposed to chronic crude oil pollution. Pre-adapted consortium was tested alone or in combination with inorganic nutrients in the presence (or not) of biosurfactants (rhamnolipids) in 30-day experiments. Treatment with fertilizers in the presence of biosurfactants exhibited the highest alkane and PAH degradation and showed highest growth over a period of almost 15 days. Considering the above, the use of biostimulation additives in combination with naturally pre-adapted hydrocarbon degrading consortia has proved to be a very effective treatment and it is a promising strategy in the future especially when combined with lipophilic fertilizers instead of inorganic nutrients. Such an approach becomes more pertinent when the oil spill approaches near the shoreline and immediate hydrocarbon degradation is needed. PMID:23835403

  17. Methane bioattenuation and implications for explosion risk reduction along the groundwater to soil surface pathway above a plume of dissolved ethanol.

    PubMed

    Ma, Jie; Rixey, William G; DeVaull, George E; Stafford, Brent P; Alvarez, Pedro J J

    2012-06-01

    Fuel ethanol releases can stimulate methanogenesis in impacted aquifers, which could pose an explosion risk if methane migrates into enclosed spaces where ignitable conditions exist. To assess this potential risk, a flux chamber was emplaced on a pilot-scale aquifer exposed to continuous release (21 months) of an ethanol solution (10% v:v) that was introduced 22.5 cm below the water table. Despite methane concentrations within the ethanol plume reaching saturated levels (20-23 mg/L), the maximum methane concentration reaching the chamber (21 ppm(v)) was far below the lower explosion limit in air (50,000 ppm(v)). The low concentrations of methane observed in the chamber are attributed to methanotrophic activity, which was highest in the capillary fringe. This was indicated by methane degradation assays in microcosms prepared with soil samples from different depths, as well as by PCR measurements of pmoA, which is a widely used functional gene biomarker for methanotrophs. Simulations with the analytical vapor intrusion model "Biovapor" corroborated the low explosion risk associated with ethanol fuel releases under more generic conditions. Model simulations also indicated that depending on site-specific conditions, methane oxidation in the unsaturated zone could deplete the available oxygen and hinder aerobic benzene biodegradation, thus increasing benzene vapor intrusion potential. Overall, this study shows the importance of methanotrophic activity near the water table to attenuate methane generated from dissolved ethanol plumes and reduce its potential to migrate and accumulate at the surface. PMID:22568485

  18. Reduction of Perchlorate and Nitrate by Microbial Communities in Vadose Soil

    PubMed Central

    Nozawa-Inoue, Mamie; Scow, Kate M.; Rolston, Dennis E.

    2005-01-01

    Perchlorate contamination is a concern because of the increasing frequency of its detection in soils and groundwater and its presumed inhibitory effect on human thyroid hormone production. Although significant perchlorate contamination occurs in the vadose (unsaturated) zone, little is known about perchlorate biodegradation potential by indigenous microorganisms in these soils. We measured the effects of electron donor (acetate and hydrogen) and nitrate addition on perchlorate reduction rates and microbial community composition in microcosm incubations of vadose soil. Acetate and hydrogen addition enhanced perchlorate reduction, and a longer lag period was observed for hydrogen (41 days) than for acetate (14 days). Initially, nitrate suppressed perchlorate reduction, but once perchlorate started to be degraded, the process was stimulated by nitrate. Changes in the bacterial community composition were observed in microcosms enriched with perchlorate and either acetate or hydrogen. Denaturing gradient gel electrophoresis analysis and partial sequencing of 16S rRNA genes recovered from these microcosms indicated that formerly reported perchlorate-reducing bacteria were present in the soil and that microbial community compositions were different between acetate- and hydrogen-amended microcosms. These results indicate that there is potential for perchlorate bioremediation by native microbial communities in vadose soil. PMID:16000806

  19. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  20. Neuromodulation of Aerobic Exercise—A Review

    PubMed Central

    Heijnen, Saskia; Hommel, Bernhard; Kibele, Armin; Colzato, Lorenza S.

    2016-01-01

    Running, and aerobic exercise in general, is a physical activity that increasingly many people engage in but that also has become popular as a topic for scientific research. Here we review the available studies investigating whether and to which degree aerobic exercise modulates hormones, amino acids, and neurotransmitters levels. In general, it seems that factors such as genes, gender, training status, and hormonal status need to be taken into account to gain a better understanding of the neuromodular underpinnings of aerobic exercise. More research using longitudinal studies and considering individual differences is necessary to determine actual benefits. We suggest that, in order to succeed, aerobic exercise programs should include optimal periodization, prevent overtraining and be tailored to interindividual differences, including neuro-developmental and genetically-based factors. PMID:26779053

  1. Aerobic Dance for Children: Resources and Recommendations.

    ERIC Educational Resources Information Center

    Wood, Denise A.

    1986-01-01

    Aerobic dance classes may be safe for older children, but are inappropriate for children in the fourth grade and under. Programs for these children should emphasize creativity. Resources for program development are given. (MT)

  2. 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)

  3. Aerobic dynamic feeding as a strategy for in situ accumulation of polyhydroxyalkanoate in aerobic granules.

    PubMed

    Gobi, K; Vadivelu, V M

    2014-06-01

    Aerobic dynamic feeding (ADF) strategy was applied in sequencing batch reactor (SBR) to accumulate polyhydroxyalkanoate (PHA) in aerobic granules. The aerobic granules were able to remove 90% of the COD from palm oil mill effluent (POME). The volatile fatty acids (VFAs) in the POME are the sole source of the PHA accumulation. In this work, 100% removal of propionic and butyric acids in the POME were observed. The highest amount of PHA produced in aerobic granules was 0.6833mgPHA/mgbiomass. The PHA formed was identified as a P (hydroxybutyrate-co-hydroxyvalerate) P (HB-co-HV). PMID:24725384

  4. Physiological responses during aerobic dance of individuals grouped by aerobic capacity and dance experience.

    PubMed

    Thomsen, D; Ballor, D L

    1991-03-01

    This study examined the effects of aerobic capacity (peak oxygen uptake) and aerobic dance experience on the physiological responses to an aerobic dance routine. The heart rate (HR) and VO2 responses to three levels (intensities) of aerobic dance were measured in 27 women. Experienced aerobic dancers (AD) (mean peak VO2 = 42 ml.kg-1.min-1) were compared to subjects with limited aerobic dance experience of high (HI) (peak VO2 greater than 35 ml.kg-1.min-1) and low (LO) (peak VO2 less than 35 ml.kg-1.min-1) aerobic capacities. The results indicated the LO group exercised at a higher percentage of peak heart rate and peak VO2 at all three dance levels than did either the HI or AD groups (HI = AD). Design of aerobic dance routines must consider the exercise tolerance of the intended audience. In mixed groups, individuals with low aerobic capacities should be shown how and encouraged to modify the activity to reduce the level of exertion. PMID:2028095

  5. Role of phosphate solubilizing bacteria on rock phosphate solubility and growth of aerobic rice.

    PubMed

    Panhwar, Q A; Radziah, O; Zaharah, A R; Sariah, M; Razi, I Mohd

    2011-09-01

    Use of phosphate-solubilizing bacteria (PSB) as inoculants has concurrently increased phosphorous uptake in plants and improved yields in several crop species. The ability of PSB to improve growth of aerobic rice (Oryza sativa L.) through enhanced phosphorus (P) uptake from Christmas island rock phosphate (RP) was studied in glasshouse experiments. Two isolated PSB strains; Bacillus spp. PSB9 and PSB16, were evaluated with RP treatments at 0, 30 and 60 kg ha(-1). Surface sterilized seeds of aerobic rice were planted in plastic pots containing 3 kg soil and the effect of treatments incorporated at planting were observed over 60 days of growth. The isolated PSB strains (PSB9 and PSB16) solubilized significantly high amounts of P (20.05-24.08 mg kg(-1)) compared to non-inoculated (19-23.10 mg kg(-1)) treatments. Significantly higher P solubilization (24.08 mg kg(-1)) and plant P uptake (5.31 mg plant(-1)) was observed with the PSB16 strain at the highest P level of 60 kg ha(-1). The higher amounts of soluble P in the soil solution increased P uptake in plants and resulted in higher plant biomass (21.48 g plant(-1)). PSB strains also increased plant height (80 cm) and improved root morphology in aerobic rice. The results showed that inoculation of aerobic rice with PSB improved phosphate solubilizing activity of incorporated RP. PMID:22319876

  6. Agricultural potential of anaerobically digested industrial orange waste with and without aerobic post-treatment.

    PubMed

    Kaparaju, Prasad; Rintala, Jukka; Oikari, Aimo

    2012-01-01

    The potential of anaerobically digested orange waste with (AAD) and without (AD) aerobic post-treatment for use in agriculture was evaluated through chemical analyses, short-term phytotoxicity and long-term plant assays. Chemical analyses showed that AD contained ammonia and organic acids, and aerobic post-treatment did not significantly remove these phytotoxins. The N:P2O5:K2O ratio in AD was 1:0.26:0.96 and aerobic post-treatment did not change the composition in AAD except for K2O (1:0.26:1.24). Heavy metal contents in AD and AAD were more or less the same and were below the upper limit recommended for non-sewage sludge application on agricultural soils. Short-term phytotoxicity tests showed that seed germination and root elongation of Chinese cabbage and ryegrass were severely inhibited at digestate concentrations of 60-100%. Germination index values were well below the score of 50% required to indicate the phytotoxic-free nature of compost. Long-term plant assays showed that AD and AAD, when supplemented with a base fertilizer, resulted in higher plant growth, and fresh weight and dry matter production than AD without base fertilizer. The results thus indicate that aerobic post-treatment did not have any significant beneficial effect on reducing phytotoxicity, and AD could be used as such on agricultural soils, especially with high P. PMID:22519091

  7. Influence of sediment on the fate and toxicity of a polyethoxylated tallowamine surfactant system (MON 0818) in aquatic microcosms

    USGS Publications Warehouse

    Wang, N.; Besser, J.M.; Buckler, D.R.; Honegger, J.L.; Ingersoll, C.G.; Johnson, B.T.; Kurtzweil, M.L.; MacGregor, J.; McKee, M.J.

    2005-01-01

    The fate and toxicity of a polyethoxylated tallowamine (POEA) surfactant system, MON 0818, was evaluated in water-sediment microcosms during a 4-d laboratory study. A surfactant solution of 8 mg l-1 nominal concentration was added to each of nine 72-l aquaria with or without a 3-cm layer of one of two natural sediments (total organic carbon (TOC) 1.5% or 3.0%). Control well water was added to each of nine additional 72-l aquaria with or without sediment. Water samples were collected from the microcosms after 2, 6, 24, 48, 72, and 96 h of aging to conduct 48-h toxicity tests with Daphnia magna and to determine surfactant concentrations. Elevated mortality of D. magna (43-83%) was observed in overlying water sampled from water-only microcosms throughout the 96-h aging period, whereas elevated mortality (23-97%) was only observed in overlying water sampled from water-sediment microcosms during the first 24 h of aging. Measured concentrations of MON 0818 in water-only microcosms remained relatively constant (4-6 mg l-1) during the 96-h period, whereas the concentrations in overlying water from microcosms containing either of the two types of sediment dissipated rapidly, with half-lives of 13 h in the 3.0% TOC sediment and 18 h in the 1.5% TOC sediment. Both toxicity and the concentration of MON 0818 in overlying water decreased more rapidly in microcosms containing sediment with the higher percent TOC and clay and with a higher microbial biomass. Mortality of D. magna was significantly correlated with surfactant concentrations in the overlying water. These results indicate that the toxicity of the POEA surfactant in water rapidly declines in the presence of sediment due to a reduction in the surfactant concentration in the overlying water above the sediment.

  8. Degredation of [{sup 14}C]-propargite in soil

    SciTech Connect

    Comezoglu, S.N.; Ly, V.T.; Wu, J.

    1996-10-01

    The degradation of {sup 14}C-labeled propargite in soil was investigated in three different test conditions, namely, aerobic soil, anaerobic soil, aerobic aquatic, and anaerobic aquatic. All studies were conducted at {approximately}25{degrees}C in the dark with treatment rates of either 5 ppm or 6 ppm and were conducted for a period of one year except the anaerobic soil and aerobic aquatic study which were conducted for two months and one month, respectively. The apparent T{sub 1/2} values observed were {approximately}38 days, {approximately}47 days, {approximately}67 days and {approximately}64 days for aerobic aquatic, anaerobic aquatic, aerobic soil and anaerobic soil studies, respectively. The soil and test systems were extracted with organic solvent followed by radiocounting and chromatographic analysis. Major metabolites were isolated and identified by co-chromatography as well as mass spectrometry (GC/MS and/or LC/MS). A number of products were detected which included p-tertiary butylphenoxy cyclohexanol (TBPC), 2-[4-(2-hydroxycyclohexoxy) phenyl]-2,2-dimethyl acetic acid (TBPC-acid), p-tertiarybutyl phenol (PTBP), and 2-(p-tertiarybutyl phenoxy) cyclohexanol sulfuric acid as the identified major products. The averaged overall recoveries for the test substance in all studies were excellent (>90%). Data indicated that the propargite degraded at a moderate rate in hydrosoils either aerobically or anaerobically while in terrestrial soil, the degradation was slowed down after several months of incubation.

  9. Stable carbon isotope fractionation during aerobic biodegradation of chlorinated ethenes

    SciTech Connect

    Chu, Kung-Hui; Mahendra, Shaily; Song, Donald L.; Conrad, Mark E.; Alvarez-Cohen, Lisa

    2003-06-01

    Stable isotope analysis is recognized as a powerful tool for monitoring, assessing, and validating in-situ bioremediation processes. In this study, kinetic carbon isotope fractionation factors () associated with the aerobic biodegradation of vinyl chloride (VC), cis-1,2-dichloroethylene (cDCE), and trichloroethylene (TCE) were examined. Of the three solvents, the largest fractionation effects were observed for biodegradation of VC. Both metabolic and cometabolic VC degradation were studied using Mycobacterium aurum L1 (grown on VC), Methylosinus trichosporium OB3b (grown on methane), Mycobacterium vaccae JOB 5 (grown on propane), and two VC enrichment cultures seeded from contaminated soils of Alameda Point and Travis Air Force Base, CA. M. aurum L1 caused the greatest fractionation (= -5.7) while for the cometabolic cultures, values ranged from -3.2 to -4.8. VC fractionation patterns for the enrichment cultures were within the range of those observed for the metabolic and cometabolic cultures (= -4.5 to -5.5). The fractionation for cometabolic degradation of TCE by Me. trichosporium OB3b was low (= -1.1), while no quantifiable carbon isotopic fractionation was observed during the cometabolic degradation of cDCE. For all three of the tested chlorinated ethenes, isotopic fractionation measured during aerobic degradation was significantly smaller than that reported for anaerobic reductive dechlorination. This study suggests that analysis of compound-specific isotopic fractionation could assist in determining whether aerobic or anaerobic degradation of VC and cDCE predominates in field applications of in-situ bioremediation. In contrast, isotopic fractionation effects associated with metabolic and cometabolic reactions are not sufficiently dissimilar to distinguish these processes in the field.

  10. The fate and transport of the Cry1Ab protein in an agricultural field and laboratory aquatic microcosms.

    PubMed

    Strain, Katherine E; Lydy, Michael J

    2015-08-01

    Genetically engineered crops expressing insecticidal crystalline proteins derived from Bacillus thuringiensis (Bt), were commercialized almost two decades ago as a means to manage agricultural pests. The Bt proteins are highly specific and only lethal upon ingestion, limiting the scope of toxicity to target insects. However, concern of exposure to non-target organisms and negative public perceptions regarding Bt crops has caused controversy surrounding their use. The objective of this research was to monitor the fate and transport of a Bt protein, Cry1Ab, in a large-scale agricultural field containing maize expressing the Cry1Ab protein and a non-Bt near isoline, and in aquatic microcosms. The highest environmental concentrations of the Cry1Ab protein were found in runoff water and sediment, up to 130ngL(-1) and 143ngg(-1) dry weight, respectively, with the Cry1Ab protein detected in both Bt and non-Bt maize fields. As surface runoff and residual crop debris can transport Bt proteins to waterways adjacent to agricultural fields, a series of laboratory experiments were conducted to determine the potential fate of the Cry1Ab protein under different conditions. The results showed that sediment type and temperature can influence the degradation of the Cry1Ab protein in an aquatic system and that the Cry1Ab protein can persist for up to two months. Although Cry1Ab protein concentrations measured in the field soil indicate little exposure to terrestrial organisms, the consistent input of Bt-contaminated runoff and crop debris into agricultural waterways is relevant to understanding potential consequences to aquatic species. PMID:25828252

  11. CO2 and CH4 Production in Low-Temperature Soil Incubations from Low and High Centered Polygons, Barrow, Alaska, 2012-2013

    DOE Data Explorer

    Taniya RoyChowdhury; David Graham; Stan Wullschleger

    2016-08-29

    The dataset consists of respiration and methane production rates obtained from soil microcosm studies carried out under controlled temperature and incubation conditions. Soils represent the low- and high-centered polygon active layers and permafrost (when present) from the NGEE-Arctic Intensive Study Site 1.

  12. CO2 and CH4 Production and CH4 Oxidation in Low Temperature Soil Incubations from Flat- and High-Centered Polygons, Barrow, Alaska, 2012

    DOE Data Explorer

    David E. Graham; Jianqiu Zheng; Taniya RoyChowdhury

    2016-08-31

    The dataset consists of respiration and methane production rates and methane oxidation potential obtained from soil microcosm studies carried out under controlled temperature and incubation conditions. Soils cores collected in 2012 represent the flat- and high-centered polygon active layers and permafrost (when present) from the NGEE Arctic Intensive Study Site 1, Barrow, Alaska.

  13. Assessing microbial responses to iron enrichment in the Subarctic Northeast Pacific: Do microcosms reproduce the in situ condition?

    NASA Astrophysics Data System (ADS)

    Scarratt, M. G.; Marchetti, A.; Hale, M. S.; Rivkin, R. B.; Michaud, S.; Matthews, P.; Levasseur, M.; Sherry, N.; Merzouk, A.; Li, W. K. W.; Kiyosawa, H.

    2006-10-01

    A microcosm experiment was conducted in the NE Pacific in July 2002 to compare the microbial response between microcosms and the Subarctic Ecosystem Response to Iron-Enrichment Study (SERIES) in situ iron-enrichment experiment. Seawater microcosms (20 L) were incubated aboard ship under natural light using three treatments: (1) low-iron seawater amended with 4 nmol l -1 FeSO 4 (+Fe); (2) low-iron seawater amended with 4 nmol l -1 FeSO 4 and 86 nmol l -1 GeO 2 (+Fe+Ge); (3) seawater collected from the in situ Fe-enriched patch (PW). The +Fe+Ge treatment used germanium to control diatom growth to assess the role of diatoms in dimethylsulfoniopropionate (DMSP) production. The following variables were measured in the microcosms and in situ: chlorophyll a (chl a), nitrate ( NO3-), silicic acid (Si(OH) 4), phytoplankton abundance and species identification, bacterial abundance (including estimates of low- and high-DNA bacteria), bacterial production, bacterial specific growth rate, particulate and dissolved DMSP and dimethylsulfide (DMS) concentrations. There was little or no significant difference (ANCOVA) in the response of most variables between the +Fe and PW microcosms, but large differences were observed between both these treatments and the in situ data from the enriched patch. Chl a in all microcosms increased from ambient levels (approx. 0.5-1 μg l -1) to approx. 4.5-6.2 μg l -1 after 11 d incubation, when NO3- was fully depleted from all microcosms. During this same period, in situ chl a increased more slowly to a maximum of 2.9 μg l -1 on day 11. Nanophytoplankton and picophytoplankton were more abundant in the microcosms relative to the in situ community, which became dominated by large diatoms. Bacterial abundance was similar in the microcosms and in situ, but bacterial production was significantly higher in the microcosms. While neither DMSP d nor DMS accumulation showed significant differences between the microcosms and in situ , particulate DMSP

  14. Taxonomy of Aerobic Marine Eubacteria

    PubMed Central

    Baumann, Linda; Baumann, Paul; Mandel, M.; Allen, Richard D.

    1972-01-01

    Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are

  15. Taxonomy of aerobic marine eubacteria.

    PubMed

    Baumann, L; Baumann, P; Mandel, M; Allen, R D

    1972-04-01

    Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are

  16. Aerobic Excercise and Research Opportunities to Benefit Impaired Children. (Project AEROBIC). Final Report.

    ERIC Educational Resources Information Center

    Idaho Univ., Moscow.

    The final report summarizes accomplishments of Project AEROBIC (Aerobic Exercise and Research Opportunities to Benefit Impaired Children), which provided a physical education exercise program for severely, profoundly, and multiply handicapped children aged 10-21. Activities are outlined for the 3 year period and include modification of exercise…

  17. U(VI) bioreduction with emulsified vegetable oil as the electron donor-- Microcosm tests and model development

    SciTech Connect

    Tang, Guoping; Wu, Wei-min; Watson, David B; Parker, Jack C.; Schadt, Christopher Warren; Brooks, Scott C; Shi, Xiaoqing

    2013-01-01

    Microcosm tests were conducted to study U(VI) bioreduction in contaminated sediments with emulsified vegetable oil (EVO) as the electron donor. In the microcosms, EVO was degraded by indigenous microorganisms and stimulated Fe, U, and sulfate bioreduction, and methanogenesis. Removal of aqueous U occurred concurrently with sulfate reduction, with more reduction of total U in the case of higher initial sulfate concentrations. X-ray absorption near-edge spectroscopy (XANES) analysis confirmed U(VI) reduction to U(IV). As the acetate concentration peaked in 10~20 days in oleate microcosms, the maximum was reached in 100~120 days in the EVO microcosms, indicating that EVO hydrolysis was rate-limiting. The acetate accumulation was sustained over 50 days longer in the oleate and EVO than in the ethanol microcosms, suggesting that acetate-utilizing methanogenesis was slower in the cases of oleate and EVO. Both slow hydrolysis and methanogenesis could contribute to potential sustained bioreduction in field application. Biogeochemical models were developed to couple degradation of EVO, production and oxidation of long-chain fatty acids, glycerol, acetate, and hydrogen, reduction of Fe(III), U(VI) and sulfate, and methanogenesis with growth and decay of microbial functional groups. The models were used to simulate the coupled processes in a field test in a companion article.

  18. 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

  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. Complete Genome Sequence of the Aerobic Facultative Methanotroph Methylocella silvestris BL2▿

    PubMed Central

    Chen, Yin; Crombie, Andrew; Rahman, M. Tanvir; Dedysh, Svetlana N.; Liesack, Werner; Stott, Matthew B.; Alam, Maqsudul; Theisen, Andreas R.; Murrell, J. Colin; Dunfield, Peter F.

    2010-01-01

    Methylocella silvestris BL2 is an aerobic methanotroph originally isolated from an acidic forest soil in Germany. It is the first fully authenticated facultative methanotroph. It grows not only on methane and other one-carbon (C1) substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate. Here we report the full genome sequence of this bacterium. PMID:20472789

  1. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Palumbo, Anthony Vito; Ravel, Bruce; Phelps, Tommy Joe; Schadt, Christopher Warren; Brandt, Craig C

    2009-01-01

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  2. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Madden, Andrew S.; Palumbo, Anthony V.; Ravel, Bruce; Vishnivetskaya, Tatiana A.; Phelps, Tommy J.; Schadt, Christopher W.; Brandt, Craig C.

    2009-03-16

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  3. Utility of Microcosm Studies for Predicting Phylloplane Bacterium Population Sizes in the Field

    PubMed Central

    Kinkel, L. L.; Wilson, M.; Lindow, S. E.

    1996-01-01

    Population sizes of two ice nucleation-active strains of Pseudomonas syringae were compared on leaves in controlled environments and in the field to determine the ability of microcosm studies to predict plant habitat preferences in the field. The P. syringae strains investigated were the parental strains of recombinant deletion mutant strains deficient in ice nucleation activity that had been field tested for their ability to control plant frost injury. The population size of the P. syringae strains was measured after inoculation at three field locations on up to 40 of the same plant species that were studied in the growth chamber. There was seldom a significant relationship between the mean population size of a given P. syringae strain incubated under either wet or dry conditions in microcosms and the mean population size which could be recovered from the same species when inoculated in the field. Specifically, on some plant species, the population size recovered from leaves in the field was substantially greater than from that species in a controlled environment, while for other plant species field populations were significantly smaller than those observed under controlled conditions. Population sizes of inoculated P. syringae strains, however, were frequently highly positively correlated with the indigenous bacterial population size on the same plant species in the field, suggesting that the ability of a particular plant species to support introduced bacterial strains is correlated with its ability to support large bacterial populations or that indigenous bacteria enhance the survival of introduced strains. Microcosm studies therefore seem most effective at assessing possible differences between parental and recombinant strains under a given environmental regime but are limited in their ability to predict the specific population sizes or plant habitat preferences of bacteria on leaves under field conditions. PMID:16535405

  4. Tracking the Response of Burkholderia cepacia G4 5223-PR1 in Aquifer Microcosms

    PubMed Central

    Winkler, J.; Timmis, K. N.; Snyder, R. A.

    1995-01-01

    The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of microbial population dynamics to define persistence and activity from both efficacy and risk assessment perspectives. Burkholderia cepacia G4 5223-PR1 is a Tn5 insertion mutant which constitutively expresses a toluene ortho-monooxygenase that degrades trichloroethylene (TCE). This ability of G4 5223-PR1 to degrade TCE without aromatic induction may be useful for bioremediation of TCE-containing aquifers and groundwater. Thus, a simulated aquifer sediment system and groundwater microcosms were used to monitor the survival of G4 5223-PR1. The fate of G4 5223-PR1 in sediment was monitored by indirect immunofluorescence microscopy, a colony blot assay, and growth on selective medium. G4 5223-PR1 was detected immunologically by using a highly specific monoclonal antibody which reacted against the O-specific polysaccharide chain of the lipopolysaccharides of this organism. G4 5223-PR1 survived well in sterilized groundwater, although in nonsterile groundwater microcosms rapid decreases in the G4 5223-PR1 cell population were observed. Ten days after inoculation no G4 5223-PR1 cells could be detected by selective plating or immunofluorescence. G4 5223-PR1 survival was greater in a nonsterile aquifer sediment microcosm, although after 22 days of elution the number of G4 5223-PR1 cells was low. Our results demonstrate the utility of monoclonal antibody tracking methods and the importance of biotic interactions in determining the persistence of introduced microorganisms. PMID:16534928

  5. MATHEMATICAL MODEL FOR THE TRANSPORT AND FATE OF ORGANIC CHEMICALS IN UNSATURATED/SATURATED SOILS

    EPA Science Inventory

    A mathematical model, simulating the transport and fate of nonionizable organic compounds in unsaturated/saturated porous media (soils) in a terrestrial microcosm has been developed. Using the principles of water mass, momentum, heat energy and chemical mass balance, the three fi...

  6. Aerobic sulfur-oxidizing bacteria: Environmental selection and diversification

    NASA Technical Reports Server (NTRS)

    Caldwell, D.

    1985-01-01

    Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.

  7. Poplar lignin decomposition by gram-negative aerobic bacteria

    SciTech Connect

    Odier, E.; Janin, G.; Monties, B.

    1981-02-01

    Eleven gram-negative aerobic bacteria (Pseudomonadaceae and Neisseriaceae) out of 122 soil isolates were selected for their ability to assimilate poplar dioxane lignin without a cosubstrate. Dioxane lignin and milled wood lignin degradation rates ranged between 20 and 40% of initial content after 7 days in mineral medium, as determined by a loss of absorbance at 280 nm; 10 strains could degrade in situ lignin, as evidenced by the decrease of the acetyl bromide lignin content of microtome wood sections. No degradation of wood polysaccharides was detected. Lignin biodegradation by Pseudomonas 106 was confirmed by 14CO2 release from labeled poplar wood, although in lower yields compared with results obtained through chemical analysis based on acetyl bromide residual lignin determination. (Refs. 31).

  8. Degradation of ¹³C-labeled pyrene in soil-compost mixtures and fertilized soil.

    PubMed

    Adam, Iris K U; Miltner, Anja; Kästner, Matthias

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) are toxic pollutants widely distributed in the environment due to natural and anthropogenic processes. In order to mitigate tar oil contaminations with PAH, research on improving bioremediation approaches, which are sometimes inefficient, is needed. However, the knowledge on the fate of PAH-derived carbon and the microbial degraders in particular in compost-supplemented soils is still limited. Here we show the PAH carbon turnover mass balance in microcosms with soil-compost mixtures or in farmyard fertilized soil using [(13)C6]-pyrene as a model PAH. Complete pyrene degradation of 100 mg/kg of soil was observed in all supplemented microcosms within 3 to 5 months, and the residual (13)C was mainly found as carbon converted to microbial biomass. Long-term fertilization of soil with farmyard manure resulted in pyrene removal efficiency similar to compost addition, although with a much longer lag phase, higher mineralization, and lower carbon incorporation into the biomass. Organic amendments either as long-term manure fertilization or as compost amendment thus play a key role in increasing the PAH-degrading potential of the soil microbial community. Phospholipid fatty acid stable isotope probing (PLFA-SIP) was used to trace the carbon within the microbial population and the amount of biomass formed from pyrene degradation. The results demonstrate that complex microbial degrader consortia rather than the expected single key players are responsible for PAH degradation in organic-amended soil. PMID:26216241

  9. Microflora in soils of desert regions

    NASA Technical Reports Server (NTRS)

    Cameron, R. E.

    1970-01-01

    Desert soil samples, collected using aseptic techniques, are low in organic matter and cation exchange capacity. Aerobic and microaerophilic bacteria are most abundant, next are algae and molds. Chemical and physical properties are determined by standard procedures, including the Kjeldahl method and the use of Munsell soil color charts.

  10. Impact of municipal wastewater effluent on seed bank response and soils excavated from a wetland impoundment

    USGS Publications Warehouse

    Finocchiaro, R.G.; Kremer, R.J.; Fredrickson, L.H.

    2009-01-01

    Intensive management of wetlands to improve wildlife habitat typically includes the manipulation of water depth, duration, and timing to promote desired vegetation communities. Increased societal, industrial, and agricultural demands for water may encourage the use of alternative sources such as wastewater effluents in managed wetlands. However, water quality is commonly overlooked as an influence on wetland soil seed banks and soils. In four separate greenhouse trials conducted over a 2-yr period, we examined the effects of municipal wastewater effluent (WWE) on vegetation of wetland seed banks and soils excavated from a wildlife management area in Missouri, USA. We used microcosms filled with one of two soil materials and irrigated with WWE, Missouri River water, or deionized water to simulate moist-soil conditions. Vegetation that germinated from the soil seed bank was allowed to grow in microcosms for approximately 100 d. Vegetative taxa richness, plant density, and biomass were significantly reduced in WWE-irrigated soil materials compared with other water sources. Salinity and sodicity rapidly increased in WWE-irrigated microcosms and probably was responsible for inhibiting germination or interfering with seedling development. Our results indicate that irrigation with WWE promoted saline-sodic soil conditions, which alters the vegetation community by inhibiting germination or seedling development. ?? 2009, The Society of Wetland Scientists.

  11. Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation.

    PubMed

    Jiang, Ying; Brassington, Kirsty J; Prpich, George; Paton, Graeme I; Semple, Kirk T; Pollard, Simon J T; Coulon, Frédéric

    2016-10-01

    The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation. PMID:27441989

  12. Effects of allylthiourea, salinity, and pH on ammonia/ammonium-oxidizing prokaryotes in mangrove sediment incubated in laboratory microcosms.

    PubMed

    Wang, Yong-Feng; Gu, Ji-Dong

    2014-04-01

    Anaerobic ammonium-oxidizing (anammox) bacteria, aerobic ammonia-oxidizing archaea (AOA) and bacteria (AOB) are three groups of ammonia/ammonium-oxidizing prokaryotes (AOPs) involved in the biochemical nitrogen cycling. In this study, the effects of allylthiourea (ATU), pH, and salinity on these three groups from mangrove sediment were investigated through microcosm incubation in laboratory. ATU treatments (50, 100, and 500 mg L(-1)) obviously affected the community structure of anammox bacteria and AOB, but only slightly for AOA. ATU began to inhibit anammox bacteria growth slightly from day 10, but had an obvious inhibition on AOA growth from the starting of the study. At 100 mg L(-1) of ATU or higher, AOB growth was inhibited, but only lasted for 5 days. The pH treatments showed that acidic condition (pH 5) had a slight effect on the community structure of anammox bacteria and AOA, but an obvious effect on AOB. Acidic condition promoted the growth of all groups of AOPs in different extent, but alkaline condition (pH 9) had a weak effect on AOB community structure and a strong effect on both anammox bacteria and AOA. Alkaline condition obviously inhibited anammox bacteria growth, slightly promoted AOA, and slightly promoted AOB in the first 20 days, but inhibited afterward. Salinity treatment showed that higher salinity (20 and 40 ‰) resulted in higher anammox bacteria diversity, and both AOA and AOB might have species specificity to salinity. High salinity promoted the growth of both anammox bacteria and AOB, inhibited AOA between 5 and 10 days, but promoted afterward. The results help to understand the role of these microbial groups in biogeochemical nitrogen cycling and their responses to the changing environments. PMID:24270897

  13. Quick stimulation of Alcanivorax sp. by bioemulsificant EPS₂₀₀₃ on microcosm oil spill simulation.

    PubMed

    Cappello, Simone; Genovese, Maria; Denaro, Renata; Santisi, Santina; Volta, Anna; Bonsignore, Martina; Mancini, Giuseppe; Giuliano, Laura; Genovese, Lucrezia; Yakimov, Michail M

    2014-01-01

    Oil spill microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on quick stimulation of hydrocarbonoclastic bacteria. Early hours of oil spill, were stimulated using an experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃); this system was monitored for 2 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out. Community composition of marine bacterioplankton was determined by 16S rRNA gene clone libraries. Data obtained indicated that bioemulsificant addition stimulated an increase of total bacterial abundance and, in particular, selection of bacteria related to Alcanivorax genus; confirming that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process. PMID:25763036

  14. Controlling the catalytic aerobic oxidation of phenols.

    PubMed

    Esguerra, Kenneth Virgel N; Fall, Yacoub; Petitjean, Laurène; Lumb, Jean-Philip

    2014-05-28

    The oxidation of phenols is the subject of extensive investigation, but there are few catalytic aerobic examples that are chemo- and regioselective. Here we describe conditions for the ortho-oxygenation or oxidative coupling of phenols under copper (Cu)-catalyzed aerobic conditions that give rise to ortho-quinones, biphenols or benzoxepines. We demonstrate that each product class can be accessed selectively by the appropriate choice of Cu(I) salt, amine ligand, desiccant and reaction temperature. In addition, we evaluate the effects of substituents on the phenol and demonstrate their influence on selectivity between ortho-oxygenation and oxidative coupling pathways. These results create an important precedent of catalyst control in the catalytic aerobic oxidation of phenols and set the stage for future development of catalytic systems and mechanistic investigations. PMID:24784319

  15. [Anaerobic-aerobic infection in acute appendicitis].

    PubMed

    Mamchich, V I; Ulitovskiĭ, I V; Savich, E I; Znamenskiĭ, V A; Beliaeva, O A

    1998-01-01

    362 patients with acute appendicitis (AA) were examined. For microbiological diagnosis of aerobic and anaerobic nonclostridial microflora we used complex accelerated methods (including evaluation of gram-negative microorganisms in comparison with tinctorial-fermentative method of differential staining according to oxygen sensitivity of catalasopositive together with aerobic and cathalasonegative anaerobic microorganisms) as well as complete bacteriologic examination with determination of sensitivity of the above microorganism to antimicrobial remedies. High rate of aerobic-anaerobic microbial associations and substantial identity of microflora from appendicis and exudate from abdominal cavity was revealed, which evidenced the leading role of endogenous microorganisms in etiology and pathogenesis of AA and peritonitis i. e. autoinfection. In patients with destructive forms of AA, complicated by peritonitis it is recommended to use the accelerated method of examination of pathologic material as well as the complete scheme of examination with the identification of the isolated microorganisms and the correction of antibiotic treatment. PMID:9511291

  16. Aerobic biodegradation of trichloroethene without auxiliary substrates.

    PubMed

    Schmidt, Kathrin R; Gaza, Sarah; Voropaev, Andrey; Ertl, Siegmund; Tiehm, Andreas

    2014-08-01

    Trichloroethene (TCE) represents a priority pollutant and is among the most frequently detected contaminants in groundwater. The current bioremediation measures have certain drawbacks like e.g. the need for auxiliary substrates. Here, the aerobic biodegradation of TCE as the sole growth substrate is demonstrated. This new process of metabolic TCE degradation was first detected in groundwater samples. TCE degradation was stable in an enriched mixed bacterial culture in mineral salts medium for over five years and repeated transfers of the culture resulting in a 10(10) times dilution of the original groundwater. Aerobic TCE degradation resulted in stoichiometric chloride formation. Stable carbon isotope fractionation was observed providing a reliable analytical tool to assess this new biodegradation process at field sites. The results suggest that aerobic biodegradation of TCE without auxiliary substrate could be considered as an option for natural attenuation or engineered bioremediation of contaminated sites. PMID:24793109

  17. Drying and recovery of aerobic granules.

    PubMed

    Hu, Jianjun; Zhang, Quanguo; Chen, Yu-You; Lee, Duu-Jong

    2016-10-01

    To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown. After three recovery batches, although with loss of part of the volatile suspended solids, all dried granules were restored most of their original size and organic matter degradation capabilities. The strains that can survive over the drying and storage periods were also identified. Once the granules were dried, they can be stored over long period of time, with minimal impact yielded by the applied drying protocols. PMID:27392096

  18. Light Structures Phototroph, Bacterial and Fungal Communities at the Soil Surface

    PubMed Central

    Davies, Lawrence O.; Schäfer, Hendrik; Marshall, Samantha; Bramke, Irene; Oliver, Robin G.; Bending, Gary D.

    2013-01-01

    The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0–3 mm) and bulk soil (3–12 mm) using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere. PMID:23894406

  19. Ammonium removal in constructed wetland microcosms as influenced by season and organic carbon load.

    PubMed

    Riley, Kate A; Stein, Otto R; Hook, Paul B

    2005-01-01

    We evaluated ammonium nitrogen removal and nitrogen transformations in three-year-old, batch-operated, subsurface wetland microcosms. Treatments included replicates of Typha latifolia, Carex rostrata, and unplanted controls when influent carbon was excluded, and C. rostrata with an influent containing organic carbon. A series of 10-day batch incubations were conducted over a simulated yearlong cycle of seasons. The presence of plants significantly enhanced ammonium removal during both summer (24 degrees C, active plant growth) and winter (4 degrees C, plant dormancy) conditions, but significant differences between plant species were evident only in summer when C. rostrata outperformed T. latifolia. The effect of organic carbon load was distinctly seasonal, enhancing C. rostrata ammonium removal in winter but having an inhibitory effect in summer. Season did not influence ammonium removal in T. latifolia or unplanted columns. Net production of organic carbon was evident year-round in units without an influent organic carbon source, but was enhanced in summer, especially for C. rostrata, which produced significantly more than T. latifolia and unplanted controls. No differences in production were evident between species in winter. COD values for C. rostrata microcosms with and without influent organic carbon converged within 24 hours in winter and 7 days in summer. Gravel sorption, microbial immobilization and sequential nitrification/denitrification appear to be the major nitrogen removal mechanisms. All evidence suggests differences between season and species are due to differences in seasonal variation of root-zone oxidation. PMID:15921269

  20. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-05-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system.

  1. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms.

    PubMed

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4-12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  2. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    PubMed Central

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  3. Methane-fed microbial microcosms show differential community dynamics and pinpoint taxa involved in communal response

    PubMed Central

    Oshkin, Igor Y; Beck, David AC; Lamb, Andrew E; Tchesnokova, Veronika; Benuska, Gabrielle; McTaggart, Tami L; Kalyuzhnaya, Marina G; Dedysh, Svetlana N; Lidstrom, Mary E; Chistoserdova, Ludmila

    2015-01-01

    We report observations on the dynamics of bacterial communities in response to methane stimulus in laboratory microcosm incubations prepared with lake sediment samples. We first measured taxonomic compositions of long-term enrichment cultures and determined that, although dominated by Methylococcaceae types, these cultures also contained accompanying types belonging to a limited number of bacterial taxa, methylotrophs and non-methylotrophs. We then followed the short-term community dynamics, in two oxygen tension regimens (150 μM and 15 μM), observing rapid loss of species diversity. In all microcosms, a single type of Methylobacter represented the major methane-oxidizing partner. The accompanying members of the communities revealed different trajectories in response to different oxygen tensions, with Methylotenera species being the early responders to methane stimulus under both conditions. The communities in both conditions were convergent in terms of their assemblage, suggesting selection for specific taxa. Our results support prior observations from metagenomics on distribution of carbon from methane among diverse bacterial populations and further suggest that communities are likely responsible for methane cycling, rather than a single type of microbe. PMID:25333464

  4. [Microcosm Simulation Study and Methylmercury Forming Mechanism at Landscape Water of City].

    PubMed

    Liu, Xiao-hong; Si, You-bin; Guo, Zi-wei; Du, Cheng-zhu; Zhu, Cong-cong

    2016-04-15

    Mercury is harmful to the environment, which has gradually become one of the research hotspots. Sediments, as a main repository of pollutants, have an important impact on water quality and the internal organisms, which deserves our research. In this paper, we focused on Hefei landscape water sediment and tried to investigate the status of inorganic mercury and methylmercury pollutions in the sediment. To study the conversion process from inorganic mercury to methylmercury and their enrichment levels and mechanism, we established the ecological chain of "sediment-water-grass-fish" through analog microcosm examination. The results were as follows: from ten water and sediment samples in Hefei landscape water sediment, we found that the contents of inorganic mercury and methylmercury ranged 11.74-13.12 µg · kg⁻¹ and 0.37-2.23 µg · kg⁻¹, respectively. The microcosm examination showed that: with increasing culture time, inorganic mercury in sediments gradually decreased. There was a phenomenon that the content of methylmercury increased at first and then decreased to reach the balance later. Both the inorganic mercury and methylmercury in water change showed an increasing trend. The enrichment contents of inorganic mercury in Egeria densa Planch, and golden mandarin fish (Siniperca scherzeri Steindachner) were low while their enrichment of methylmercury could he great. In addition, we found that both the bioaccumulation ability and the enrichment coefficient of methylmercury in the body of golden mandarin fish were the maximum during the same period. PMID:27548953

  5. Antimicrobial Susceptibility and Composition of Microcosm Dental Plaques Supplemented with Sucrose

    PubMed Central

    Pratten, J.; Wilson, M.

    1999-01-01

    The aims of this study were to evaluate the effects of repeated chlorhexidine gluconate (CHG) pulsing on the viability and bacterial composition of microcosm dental plaques derived from human saliva. The biofilms were grown on bovine enamel discs in a constant-depth film fermentor fed with an artificial saliva which was supplemented thrice daily with sucrose. The microcosm plaques had total viable anaerobic counts of 5 × 108 CFU per mm2 and consisted of 12% Actinomyces spp., 85% streptococci, and 0.2% Veillonella spp. When pulsed twice daily with 0.2% CHG, there was an immediate 1.3-log10 reduction in the total viable (anaerobic) count. However, as pulsing continued, the viable counts recovered, and after 4 days, the anaerobic count reached its pre-CHG-pulsing level, although the bacterial composition of the biofilms had changed. The results of this study show that twice-daily pulsing with 0.2% CHG over a 4-day period was ineffective at reducing the total anaerobic viable count of the biofilms but did alter their bacterial composition. PMID:10390209

  6. Effects of Mycorrhizal and Endophytic Fungi on Plant Community: a Microcosm Study

    PubMed Central

    Park, Sang-Hyun

    2007-01-01

    This study was conducted to investigate the effects of foliar endophytic fungi and arbuscular mycorrhizal fungi (AMF) on plant community structure in experimental microcosms containing an assemblage of five species of plants (Oenothera odorata, Plantago asiatica, Trifolium repens, Isodon japonicas and Aster yomena). Leaves of Sasa borealis, Potentilla fragarioides, and Viola mandshurica were collected in Chungbuk, Korea. Endophytic fungi were isolated from the surface sterilized leaves and identified to species level using molecular and morphological techniques. Four isolates of the endophytic fungi were inoculated to the leaves of host plants in the microcosms. Also, three species of AMF spores were extracted from pure cultures and the mixture of the three species inoculated to the roots of the plants. After four months of growth in a green house, effects of both symbiotic fungi on plant species diversity, community composition and productivity were examined. The plant species diversity showed significant differences with inoculation of the symbiotic fungi. Results indicate that AMF significantly affect plant productivity and plant community structure. PMID:24015095

  7. Effects of mycorrhizal and endophytic fungi on plant community: a microcosm study.

    PubMed

    Park, Sang-Hyun; Eom, Ahn-Heum

    2007-12-01

    This study was conducted to investigate the effects of foliar endophytic fungi and arbuscular mycorrhizal fungi (AMF) on plant community structure in experimental microcosms containing an assemblage of five species of plants (Oenothera odorata, Plantago asiatica, Trifolium repens, Isodon japonicas and Aster yomena). Leaves of Sasa borealis, Potentilla fragarioides, and Viola mandshurica were collected in Chungbuk, Korea. Endophytic fungi were isolated from the surface sterilized leaves and identified to species level using molecular and morphological techniques. Four isolates of the endophytic fungi were inoculated to the leaves of host plants in the microcosms. Also, three species of AMF spores were extracted from pure cultures and the mixture of the three species inoculated to the roots of the plants. After four months of growth in a green house, effects of both symbiotic fungi on plant species diversity, community composition and productivity were examined. The plant species diversity showed significant differences with inoculation of the symbiotic fungi. Results indicate that AMF significantly affect plant productivity and plant community structure. PMID:24015095

  8. Differential Decay of Wastewater Bacteria and Change of Microbial Communities in Beach Sand and Seawater Microcosms.

    PubMed

    Zhang, Qian; He, Xia; Yan, Tao

    2015-07-21

    Laboratory microcosm experiments were conducted to determine the decay kinetics of wastewater bacteria and the change of microbial communities in beach sand and seawater. Cultivation-based methods showed that common fecal indicator bacteria (FIBs; Escherichia coli, enterococci, and Clostridium perfringens) exhibited biphasic decay patterns in all microcosms. Enterococci and C. perfringens, but not E. coli, showed significantly smaller decay rates in beach sand than in seawater. Cultivation-independent qPCR quantification of 16S rRNA gene also showed significantly slower decrease of total bacterial densities in beach sand than in seawater. Microbial community analysis by next-generation sequencing (NGS) further illustrated that the decreasing relative abundance of wastewater bacteria was contrasted by the increase in indigenous beach sand and seawater microbiota, and the overall microbial community dynamics corresponded well with the decay of individual FIB populations. In summary, the differential decay of wastewater bacteria in beach sand and in seawater provides a kinetic explanation to the often-observed higher abundance of FIBs in beach sand, and the NGS-based microbial community analysis can provide valuable insights to understanding the fate of wastewater bacteria in the context of indigenous microbial communities in natural environments. PMID:26125493

  9. Methane-fed microbial microcosms show differential community dynamics and pinpoint taxa involved in communal response.

    PubMed

    Oshkin, Igor Y; Beck, David A C; Lamb, Andrew E; Tchesnokova, Veronika; Benuska, Gabrielle; McTaggart, Tami L; Kalyuzhnaya, Marina G; Dedysh, Svetlana N; Lidstrom, Mary E; Chistoserdova, Ludmila

    2015-05-01

    We report observations on the dynamics of bacterial communities in response to methane stimulus in laboratory microcosm incubations prepared with lake sediment samples. We first measured taxonomic compositions of long-term enrichment cultures and determined that, although dominated by Methylococcaceae types, these cultures also contained accompanying types belonging to a limited number of bacterial taxa, methylotrophs and non-methylotrophs. We then followed the short-term community dynamics, in two oxygen tension regimens (150 μM and 15 μM), observing rapid loss of species diversity. In all microcosms, a single type of Methylobacter represented the major methane-oxidizing partner. The accompanying members of the communities revealed different trajectories in response to different oxygen tensions, with Methylotenera species being the early responders to methane stimulus under both conditions. The communities in both conditions were convergent in terms of their assemblage, suggesting selection for specific taxa. Our results support prior observations from metagenomics on distribution of carbon from methane among diverse bacterial populations and further suggest that communities are likely responsible for methane cycling, rather than a single type of microbe. PMID:25333464

  10. Evaluation of PCB dechlorination pathways in anaerobic sediment microcosms using an anaerobic dechlorination model.

    PubMed

    Demirtepe, Hale; Kjellerup, Birthe; Sowers, Kevin R; Imamoglu, Ipek

    2015-10-15

    A detailed quantitative analysis of anaerobic dechlorination (AD) pathways of polychlorinated biphenyls (PCBs) in sediment microcosms was performed by applying an anaerobic dechlorination model (ADM). The purpose of ADM is to systematically analyze changes in a contaminant profile that result from microbial reductive dechlorination according to empirically determined dechlorination pathways. In contrast to prior studies that utilized modeling tools to predict dechlorination pathways, ADM also provides quantification of individual pathways. As only microbial reductive dechlorination of PCBs occurred in the modeled laboratory microcosms, extensive analysis of AD pathways was possible without the complicating effect of concurrent physico-chemical or other weathering mechanisms. The results from this study showed: (1) ninety three AD pathways are active; (2) tetra- to hepta-chlorobiphenyl (CB) congeners were common intermediates in several AD pathways, penta-CBs being the most frequently observed; (3) the highest rates of dechlorination were for penta-CB homologs during the initial 185 days; (4) the dominant terminal products of AD were PCB 32(26-4), 49(24-25), 51(24-26), 52(25-25), 72(25-35), 73(26-35) and 100(246-24), (5) potential toxicity of the sediment was reduced. ADM serves as a powerful tool not only for a thorough analysis of AD pathways, but also for providing necessary input for numerical fate models (as a degradation term) that investigate dechlorination products or outcome of natural attenuation, or bioremediation/bioaugmentation of PCB-impacted sediments. PMID:25913678

  11. Interactions among buffelgrass, phenanthrene and phenanthrene-degrading bacteria in gnotobiotic microcosms.

    PubMed

    Robert, Francoise M; Sun, Wenhao H; Toma, Marisa; Jones, Ryan K; Tang, Chung-Shih

    2008-07-15

    An experiment was undertaken in gnotobiotic microcosms to determine the role of buffelgrass (Cenchrus ciliaris) and a phenanthrene-degrading bacterium (strain PM600) in the degradation of phenanthrene. The Gram-negative bacterium was identified as a Sphingomonas sp. by 16S rRNA gene sequence analysis and as S. paucimobilis by biochemical tests (API 20 NE strips). Its yellow pigment corresponded to nostoxanthin and its cellular fatty acids were typical of the genus Sphingomonas. Moreover, it was devoid of lipopolysaccharides. Strain PM600 was tested for growth on mineral medium supplemented with No. 2 diesel, hexadecane, mineral oil, pristane, phenanthrene, and pyrene as single carbon sources. It was capable of utilizing phenanthrene only. In the gnotobiotic microcosms silica sand was either or not supplemented with 150 mg of phenanthrene kg(-1) sand, inoculated with strain PM600, and planted to sterile young seedlings of buffelgrass. After 28 days, 67% of the reduction of the phenanthrene concentration was assigned to degradation by the bacterium and ca. 20% to abiotic factors. No statistically significant effect of the young buffelgrass was found. In the absence of phenanthrene, the bacterial population significantly increased in the rhizosphere of buffelgrass. However, in the presence of buffelgrass and phenanthrene, the bacterial population preferentially responded to phenanthrene. The growth of buffelgrass was severely curtailed by phenanthrene in the absence of the bacterium. However, strain PM600 effectively protected buffelgrass against the phytotoxicity of phenanthrene. PMID:18569317

  12. Enhanced Horizontal Transfer of Antibiotic Resistance Genes in Freshwater Microcosms Induced by an Ionic Liquid

    PubMed Central

    Wang, Qing; Mao, Daqing; Mu, Quanhua; Luo, Yi

    2015-01-01

    The spread and propagation of antibiotic resistance genes (ARGs) is a worldwide public health concern. Ionic liquids (ILs), considered as “environmentally friendly” replacements for industrial organic solvents, have been widely applied in modern industry. However, few data have been collected regarding the potential ecological and environmental risks of ILs, which are important for preparing for their potential discharge into the environment. In this paper, the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) (0.001-5.0 g/L) was tested for its effects on facilitating ARGs horizontal transfer mediated by plasmid RP4 in freshwater microcosms. In the horizontal transfer microcosms, the transfer frequency of plasmid RP4 was significantly enhanced (60-fold higher than untreated groups) by the IL [BMIm][PF6] (1.0 g/L). Meanwhile, two strains of opportunistic pathogen Acinetobacter spp. and Salmonella spp. were isolated among the transconjugants, illustrating plasmid RP4 mediated horizontal transfer of ARGs occurred in pathogen. This could increase the risk of ARGs dissemination to human pathogens and pose great threat to public health. The cause that [BMIm[PF6] enhanced the transfer frequency of plasmid RP4 was proposed by suppressed cell membrane barrier and enhanced cell membrane permeability, which was evidenced by flow cytometry (FCM). This is the first report that some ILs facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment and thus add the adverse effects of the environmental risk of ILs. PMID:25951456

  13. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    PubMed

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems. PMID:27304868

  14. 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

  15. INACTIVATION OF ENTERIC PATHOGENS DURING AEROBIC DIGESTION OF WASTEWATER SLUDGE

    EPA Science Inventory

    The effects of aerobic and anaerobic digestion on enteric viruses, enteric bacteria, total aerobic bacteria, and intestinal parasites were studied under laboratory and field conditions. Under laboratory conditions, the temperature of the sludge digestion was the major factor infl...

  16. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  17. Soil solid phases effects on the proteomic analysis of Cupriavidus metallidurans CH34

    SciTech Connect

    Giagnoni L.; Taghavi S.; Magherini, F.; Landi, L.; van der Lelie, D.; Puglia, M.; Bianchi, L.; Bini, L.; Nannipieri, P.; Renella, G.; Modesti, A.

    2012-05-01

    Cupriavidus metallidurans CH34 is a completely sequenced soil-borne beta-proteobacterium with known genome and proteome. Comparative 2-D electrophoresis and protein mass spectrometry were used to compare the proteome of C. metallidurans CH34 from liquid culture and after incubation for 1, 3, and 12 days in microcosms containing quartz sand, kaolinite, montmorillonite, or an artificial soil. Results showed that proteome from liquid culture was similar to CH34 proteins extracted from sand and kaolinite, whereas the proteins extracted from artificial soil differed significantly and no proteins were detected from C. metallidurans CH34 incubated in the montmorillonite microcosms. Protein recovery decreased on prolonging incubation time in all microcosms. Mass spectrometry identification showed that the trend of lower recovery upon incubation time was independent on the putative function of protein. These results suggest that the soil solid phase influences the protein recovery and soil proteomic analysis and that distinction between protein recovery and protein expression in soil will be a challenging for soil proteomic researchers.

  18. Reflections on Psychotherapy and Aerobic Exercise.

    ERIC Educational Resources Information Center

    Silverman, Wade

    This document provides a series of reflections by a practicing psychologist on the uses of aerobic workouts in psychotherapy. Two case histories are cited to illustrate the contention that the mode of exercise, rather than simply its presence or absence, is the significant indicator of a patient's emotional well-being or psychopathology. The first…

  19. Aerobic Exercise Prescription for Rheumatoid Arthritics.

    ERIC Educational Resources Information Center

    Evans, Blanche W.; Williams, Hilda L.

    The use of exercise as a general treatment for rheumatoid arthritics (RA) has included range of motion, muscular strength, water exercise and rest therapy while virtually ignoring possible benefits of aerobic exercise. The purposes of this project were to examine the guidelines for exercise prescription in relation to this special population and…

  20. Media for the aerobic growth of campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of agar and sodium bicarbonate (NaHCO3) concentration on aerobic growth of Campylobacter in a fumarate-pyruvate medium was examined. The broth medium was supplemented with 0.0 to 0.2% agar and inoculated with 106 CFU/ml of Campylobacter coli 33559, Campylobacter fetus 27349, Campylobacter...

  1. Strengthening aerobic granule by salt precipitation.

    PubMed

    Chen, Yu-You; Pan, Xiangliang; Li, Jun; Lee, Duu-Jong

    2016-10-01

    Structural stability of aerobic granules is generally poor during long-term operation. This study precipitated seven salts inside aerobic granules using supersaturated solutions of (NH4)3PO4, CaCO3, CaSO4, MgCO3, Mg3(PO4)2, Ca3(PO4)2 or SiO2 to enhance their structural stability. All precipitated granules have higher interior strength at ultrasonic field and reveal minimal loss in organic matter degradation capability at 160-d sequential batch reactor tests. The strength enhancement followed: Mg3(PO4)2=CaSO4>SiO2>(NH4)3PO4>MgCO3>CaCO3=Ca3(PO4)2>original. Also, the intra-granular solution environment can be buffered by the precipitate MgCO3 to make the aerobic granules capable of degradation of organic matters at pH 3. Salt precipitation is confirmed a simple and cost-effective modification method to extend the applicability of aerobic granules for wastewater treatments. PMID:27377228

  2. AEROBIC DENITRIFICATION: IMPLICATIONS FOR NITROGEN FATE MODELING

    EPA Science Inventory

    In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrificat...

  3. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  4. Ventilation and Speech Characteristics during Submaximal Aerobic Exercise

    ERIC Educational Resources Information Center

    Baker, Susan E.; Hipp, Jenny; Alessio, Helaine

    2008-01-01

    Purpose: This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks. Method: Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO[subscript 2] max).…

  5. Adolescents' Interest and Performances in Aerobic Fitness Testing

    ERIC Educational Resources Information Center

    Zhu, Xihe; Chen, Senlin; Parrott, James

    2014-01-01

    This study examined adolescents' interest in aerobic fitness testing and its relation to the test performances. Adolescents (N = 356) from three middle schools participated in the study. The participants took two aerobic fitness tests: the Progressive Aerobic Cardiovascular Endurance Run (PACER) and One-Mile Run (1MR) with a two-day interval,…

  6. A proposed aerobic granules size development scheme for aerobic granulation process.

    PubMed

    Dahalan, Farrah Aini; Abdullah, Norhayati; Yuzir, Ali; Olsson, Gustaf; Salmiati; Hamdzah, Myzairah; Din, Mohd Fadhil Mohd; Ahmad, Siti Aqlima; Khalil, Khalilah Abdul; Anuar, Aznah Nor; Noor, Zainura Zainon; Ujang, Zaini

    2015-04-01

    Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules' size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme. PMID:25661308

  7. Application of potential phosphate-solubilizing bacteria and organic acids on phosphate solubilization from phosphate rock in aerobic rice.

    PubMed

    Panhwar, Qurban Ali; Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

    2013-01-01

    A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg(-1)), plant P uptake (0.78 P pot(-1)), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g(-1)) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH. PMID:24288473

  8. Evaluation of graphite for environmental toxicity using the standard aquatic microcosm. Technical report, June 1986-March 1987

    SciTech Connect

    Landis, W.G.; Chester, N.A.; Haley, M.V.; Johnson, D.W.; Tauber, R.M.

    1988-08-01

    The impact of a graphite dust on an aquatic ecosystem model, the Standard Aquatic microcosm (SAM), was investigated. Graphite dust produced effects that resembled eutrophication in that a diversity decreased, ammonia increased, and a photosynthesis/respiration ratio of less than one was observed in the highest concentration. Compared to brass dust, graphite has much less potential to adversely impact aquatic ecosystems.

  9. COMPARISON OF MICROBIAL TRANSFORMATION RATE COEFFICIENTS OF XENOBIOTIC CHEMICALS BETWEEN FIELD-COLLECTED AND LABORATORY MICROCOSM MICROBIOTA

    EPA Science Inventory

    Two second-order transformation rate coefficients--kb, based on total plate counts, and kA, based on periphyton-colonized surface areas--were used to compare xenobiotic chemical transformation by laboratory-developed (microcosm) and by field-collected microbiota. Similarity of tr...

  10. ENRICHMENT OF CADMIUM-MEDIATED ANTIBIOTIC-RESISTANT BACTERIA IN A DOUGLAS-FIR 'PSEUDOTSUGA MENZIESII' LITTER MICROCOSM

    EPA Science Inventory

    A set of Douglas-fir needle microcosms was amended with cadmium, acid, a combination of both, or neither. After 2 weeks of incubation, bacterial colony counts were made of litter homogenates inoculated onto agar media containing an antibiotic (streptomycin, chloromycetin, ampicil...

  11. Hydrocarbon biodegradation by Arctic sea-ice and sub-ice microbial communities during microcosm experiments, Northwest Passage (Nunavut, Canada).

    PubMed

    Garneau, Marie-Ève; Michel, Christine; Meisterhans, Guillaume; Fortin, Nathalie; King, Thomas L; Greer, Charles W; Lee, Kenneth

    2016-10-01

    The increasing accessibility to navigation and offshore oil exploration brings risks of hydrocarbon releases in Arctic waters. Bioremediation of hydrocarbons is a promising mitigation strategy but challenges remain, particularly due to low microbial metabolic rates in cold, ice-covered seas. Hydrocarbon degradation potential of ice-associated microbes collected from the Northwest Passage was investigated. Microcosm incubations were run for 15 days at -1.7°C with and without oil to determine the effects of hydrocarbon exposure on microbial abundance, diversity and activity, and to estimate component-specific hydrocarbon loss. Diversity was assessed with automated ribosomal intergenic spacer analysis and Ion Torrent 16S rRNA gene sequencing. Bacterial activity was measured by (3)H-leucine uptake rates. After incubation, sub-ice and sea-ice communities degraded 94% and 48% of the initial hydrocarbons, respectively. Hydrocarbon exposure changed the composition of sea-ice and sub-ice communities; in sea-ice microcosms, Bacteroidetes (mainly Polaribacter) dominated whereas in sub-ice microcosms, the contribution of Epsilonproteobacteria increased, and that of Alphaproteobacteria and Bacteroidetes decreased. Sequencing data revealed a decline in diversity and increases in Colwellia and Moritella in oil-treated microcosms. Low concentration of dissolved organic matter (DOM) in sub-ice seawater may explain higher hydrocarbon degradation when compared to sea ice, where DOM was abundant and composed of labile exopolysaccharides. PMID:27387912

  12. Use Of Statistical Tools To Evaluate The Reductive Dechlorination Of High Levels Of TCE In Microcosm Studies

    EPA Science Inventory

    A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study ...

  13. EVALUATION OF TERRESTRIAL MICROCOSMS FOR DETECTION, FATE, AND SURVIVAL ANALYSIS OF GENETICALLY ENGINEERED MICROORGANISMS AND THEIR RECOMBINANT GENETIC MATERIAL

    EPA Science Inventory

    Terrestrial microcosms have been used for several decades by researcher to evaluate the fate and transport of xenobiotics in the environment; however, very little information is available on their application to the fate, survival, and transport of recombinant bacteria and microb...

  14. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth

  15. Soil surface colonization by phototrophic indigenous organisms, in two contrasted soils treated by formulated maize herbicide mixtures.

    PubMed

    Joly, Pierre; Misson, Benjamin; Perrière, Fanny; Bonnemoy, Frédérique; Joly, Muriel; Donnadieu-Bernard, Florence; Aguer, Jean-Pierre; Bohatier, Jacques; Mallet, Clarisse

    2014-11-01

    Soil phototrophic microorganisms, contributors to soil health and food webs, share their particular metabolism with plants. Current agricultural practices employ mixtures of pesticides to ensure the crops yields and can potentially impair these non-target organisms. However despite this environmental reality, studies dealing the susceptibility of phototrophic microorganisms to pesticide mixtures are scarce. We designed a 3 months microcosm study to assess the ecotoxicity of realistic herbicide mixtures of formulated S-metolachlor (Dual Gold Safeneur(®)), mesotrione (Callisto(®)) and nicosulfuron (Milagro(®)) on phototrophic communities of two soils (Limagne vertisol and Versailles luvisol). The soils presented different colonizing communities, with diatoms and chlorophyceae dominating communities in Limagne soil and cyanobacteria and bryophyta communities in Versailles soil. The results highlighted the strong impairment of Dual Gold Safeneur(®) treated microcosms on the biomass and the composition of both soil phototrophic communities, with no resilience after a delay of 3 months. This study also excluded any significant mixture effect on these organisms for Callisto(®) and Milagro(®) herbicides. We strongly recommend carrying on extensive soil studies on S-metolachlor and its commercial formulations, in order to reconsider its use from an ecotoxicological point of view. PMID:25129149

  16. MOLECULAR ANALYSIS OF MICROBIAL COMMUNITY STRUCTURES IN PRISTINE AND CONTAMINATED AQUIFERS: FIELD AND LABORATORY MICROCOSM EXPERIMENTS

    EPA Science Inventory

    This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminted (NC) and (ii) examine alterations in micro...

  17. The Gut of the Soil Microarthropod Folsomia candida (Collembola) Is a Frequently Changeable but Selective Habitat and a Vector for Microorganisms

    PubMed Central

    Thimm, Torsten; Hoffmann, Andrea; Borkott, Heinz; Charles Munch, Jean; Tebbe, Christoph C.

    1998-01-01

    Interaction potentials between soil microarthropods and microorganisms were investigated with Folsomia candida (Insecta, Collembola) in microcosm laboratory experiments. Microscopic analysis revealed that the volumes of the simple, rod-shaped guts of adult specimens varied with their feeding activity, from 0.7 to 11.2 nl. A dense layer of bacterial cells, associated with the peritrophic membrane, was detected in the midgut by scanning electron microscopy. Depending on the molting stage, which occurred at intervals of approximately 4 days, numbers of heterotrophic, aerobic gut bacteria changed from 4.9 × 102 to 2.3 × 106 CFU per specimen. A total of 11 different taxonomic bacterial groups and the filamentous fungus Acremonium charticola were isolated from the guts of five F. candida specimens. The most abundant isolate was related to Erwinia amylovora (96.2% DNA sequence similarity to its 16S rRNA gene). F. candida preferred to feed on Pseudomonas putida and three indigenous gut isolates rather than eight different type culture strains. When luciferase reporter gene-tagged bacterial strains were pulse fed to F. candida, gut isolates were continuously shed for 8 days to several weeks but Escherichia coli HB101 was shed for only 1 day. Ratios of ingested to released bacterial cells demonstrated that populations of nonindigenous gut bacteria like Sinorhizobium meliloti L33 and E. coli HB101 were reduced by more than 4 orders of magnitude but that the population of gut isolate Alcaligenes faecalis HR4 was reduced only 500-fold. This work demonstrates that F. candida represents a frequently changeable but selective habitat for bacteria in terrestrial environments and that microarthropods have to be considered factors that modify soil microbial communities. PMID:9647845

  18. A comparative study of microbial communities in four soil slurries capable of RDX degradation using illumina sequencing.

    PubMed

    Jayamani, Indumathy; Cupples, Alison M

    2015-06-01

    The nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has contaminated many military sites. Recently, attempts to remediate these sites have focused on biostimulation to promote RDX biodegradation. Although many RDX degrading isolates have been obtained in the laboratory, little is known about the potential of microorganisms to degrade this chemical while existing in a soil community. The current study examined and compared the RDX degrading communities in four soil slurries to elucidate the potential of natural systems to degrade this chemical. These soils were selected as they had no previous exposure to RDX, therefore their microbial communities offered an excellent baseline to determine changes following RDX degradation. High throughput sequencing was used to determine which phylotypes experienced an increase in relative abundance following RDX degradation. For this, total genomic DNA was sequenced from (1) the initial soil, (2) soil slurry microcosms following RDX degradation and (3) control soil slurry microcosms without RDX addition. The sequencing data provided valuable information on which phylotypes increased in abundance following RDX degradation compared to control microcosms. The most notable trend was the increase in abundance of Brevundimonas and/or unclassified Bacillaceae 1 in the four soils studied. Although isolates of the family Bacillaceae 1 have previously been linked to RDX degradation, isolates of the genus Brevundimonas have not been previously associated with RDX degradation. Overall, the data suggest these two phylotypes have key roles in RDX degradation in soil communities. PMID:25913213

  19. Microbial activity in Alaskan taiga soils contaminated by crude oil in 1976

    SciTech Connect

    Monroe, E.M.; Lindstrom, J.E.; Brown, E.J.; Raddock, J.F. |

    1995-12-31

    Biodegradation, often measured via microbial activity, includes destruction of environmental pollutants by living microorganisms and is dependent upon many physical and chemical factors. Effects of mineral nutrients and organic matter on biodegradation of Prudhoe Bay crude oil were investigated at a nineteen-year-old oil spill site in Alaskan taiga. Microcosms of two different soil types from the spill site; one undeveloped soil with forest litter and detritus (O horizon) and one more developed with lower organic content (A horizon), were treated with various nitrogen and phosphorus amendments, and incubated for up to six weeks. Each microcosm was sampled periodically and assayed for hydrocarbon mineralization potential using radiorespirometry, for total carbon dioxide respired using gas chromatography, and for numbers of hydrocarbon-degrading bacteria and heterotrophic bacteria using most probable number counting techniques. Organic matter in the O horizon soil along with combinations of mineral nutrients were found to stimulate microbial activity. No combination of mineral nutrient additions to the A horizon soil stimulated any of the parameters above those measured in control microcosms. The results of this study indicate that adding mineral nutrients and tilling the O horizon into the A horizon of subarctic soils contaminated with crude oil, would stimulate microbial activity, and therefore the biodegradation potential, ultimately increasing the rate of destruction of crude oil in these soils.

  20. Experimental modeling of the processes resulting from the introduction of the transgenic microorganism Escherichia coli Z905/pPHL7 (lux+) into aquatic microcosms

    NASA Astrophysics Data System (ADS)

    Kargatova, T.; Popova, L.; Pechurkin, N.

    The processes resulting from the introduction of the transgenic microorganism (TM) E. coli Z905/pPHL7 into aquatic microcosms have been modeled experimentally. It has been shown that the TM E. coli is able to adapt to a long co-existence with aboriginal heterotrophic microflora, whatever the structure of a microcosm. In more complex microcosms the numerical dynamics of the introduced E. coli Z905/pPHL7 population is more stable. In the TM populations staying in the microcosms for a prolonged time changes are recorded in the phenotypic expression of plasmid genes (ampicillin resistance and the luminescence level) and chromosome genes (morphological and physiological traits). However, in every study microcosm the recombinant plasmid persists in the TM cells during 6 years after the introduction, and as the population adapts to the conditions of the microcosms, the efficiency of the cloned gene expression in the cells is restored. In the microcosms with high microalgal counts (107 cells/ml), cells with a high threshold of sensitivity to ampicillin dominate in the population of the TM E. coli Z905/pPHL7.

  1. Experimental evaluation of the processes resulting from the introduction of the transgenic microorganism Escherichia coli Z905/pPHL7 ( lux+) into aquatic microcosms

    NASA Astrophysics Data System (ADS)

    Kargatova, T. V.; Boyandin, A. N.; Popova, L. Yu.; Pechurkin, N. S.

    The processes resulting from the introduction of the tranagenic microorganism (TM) E. coli Z905/pPHL7 into aquatic microcosms have been modeled experimentally. It has been shown that the TM E. coli is able to adapt to a long co-existence with indigenous heterotropbic microflora in variously structured microcosms. In more complex microcosms the numerical dynamics of the introduced E. coli Z905/pPHL7 population is more stable. In the TM populations staying in the microcosms for a prolonged time, changes are recorded in the phenotypic expression of plasmid genes (ampicillin resistance and the luminescence level) and chromosome genes (morphological and physiological traits). However, in our study microcosms, the recombinant plasmid persisted in the TM cells for 6 years after the introduction, and as the population adapts to the conditions of the microcosms, the efficiency of the cloned gene expression in the cells is restored. In the microcosms with high microalgal counts (10 7 cells/ml), cells with a high threshold of sensitivity to ampicillin dominate in the population of the TM E. coli Z905/pPHL7.

  2. Aerobic biodegradation of organic compounds in hydraulic fracturing fluids.

    PubMed

    Kekacs, Daniel; Drollette, Brian D; Brooker, Michael; Plata, Desiree L; Mouser, Paula J

    2015-07-01

    Little is known of the attenuation of chemical mixtures created for hydraulic fracturing within the natural environment. A synthetic hydraulic fracturing fluid was developed from disclosed industry formulas and produced for laboratory experiments using commercial additives in use by Marcellus shale field crews. The experiments employed an internationally accepted standard method (OECD 301A) to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from an aqueous solution by activated sludge and lake water microbial consortia for two substrate concentrations and four salinities. Microbial degradation removed from 57 % to more than 90 % of added DOC within 6.5 days, with higher removal efficiency at more dilute concentrations and little difference in overall removal extent between sludge and lake microbe treatments. The alcohols isopropanol and octanol were degraded to levels below detection limits while the solvent acetone accumulated in biological treatments through time. Salinity concentrations of 40 g/L or more completely inhibited degradation during the first 6.5 days of incubation with the synthetic hydraulic fracturing fluid even though communities were pre-acclimated to salt. Initially diverse microbial communities became dominated by 16S rRNA sequences affiliated with Pseudomonas and other Pseudomonadaceae after incubation with the synthetic fracturing fluid, taxa which may be involved in acetone production. These data expand our understanding of constraints on the biodegradation potential of organic compounds in hydraulic fracturing fluids under aerobic conditions in the event that they are accidentally released to surface waters and shallow soils. PMID:26037076

  3. A microcosm investigation of fe (iron) removal using macrophytes of ramsar lake: A phytoremediation approach.

    PubMed

    Singh, Mayanglambam Muni; Rai, Prabhat Kumar

    2016-12-01

    The present study deals with the microcosm study of Fe (Iron) phytoremediation using Eichhornia crassipes, Lemna minor, Pistia stratiotes and Salvinia cucullata species collected from the Loktak Lake, a Ramsar Site which exists in north-eastern India (an Indo-Burma hotspot region). Efficiency of these four macrophytes was compared using different Fe concentrations of 1 mg L(-1), 3 mg L(-1) and 5 mg L(-1) for 4 days, 8 days and 12 days, respectively. E. crassipes was the most efficient macrophyte whereas L. minor was the least efficient. E. crassipes removed the highest percentage of Fe, i.e. 89% from 1 mg L(-1), 81.3% from 3 mg L(-1) and 73.2% from 5 mg L(-1) in 12-day experiment. PMID:27258126

  4. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    NASA Astrophysics Data System (ADS)

    Chen, Haiyan; Peng, Jianke; Fu, Li; Wang, Xincheng; Xie, Yan

    2016-04-01

    In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  5. Expression and transfer of engineered catabolic pathways harbored by Pseudomonas spp. introuduced into activated sludge microcosms

    SciTech Connect

    Nublein, K.; Maris, D.; Timmis, K.; Dwyer, D.F. )

    1992-10-01

    Two genetically engineered microorganisms (GEMs), Pseudomonas sp. strain B13 FR1(pFRC20P) (FR120) and Pseudomonas putida KT2440(pWWO-EB62) (EB62), were introduced into activated sludge microcosms that had the level of aeration, nutrient makeup, and microbial community structure of activated sludge reactors. FR120 contains an experimentally assembled ortho cleavage route for simultaneous degradation of 3-chlorobenzoate (3CB) and 4-methyl benzoate (4MB); EB62 contains a derivative TOL plasmid-encoded degradative pathway for toluene experimentally evolved so that it additionally processes 4-ethyl benzoate (4EB). Experiments assessed survival of the GEMs, their ability to degrade target substrates, and lateral transfer of plasmid-encoded recombinant DNA.

  6. Recolonisation of mine tailing by meiofauna in mesocosm and microcosm experiments.

    PubMed

    Gwyther, David; Batterham, Grant J; Waworuntu, Jorina; Gultom, Tonny H; Prayogo, Windy; Susetiono; Karnan

    2009-06-01

    The Batu Hijau copper/gold mine in Sumbawa, Indonesia processes ore at approximately 130,000tpd and discharges tailing via a submarine pipeline to depths below 3000m at the base of a submarine canyon. The study investigated recolonisation of tailing by meiofauna and its dependence on subsequent accumulation of natural sediment. Microcosm and mesocosm scale experiments were carried out using two tailing and two control samples, the latter comprising defaunated and unaffected natural sediment. All test materials were similar in physical and chemical respects, except for the higher copper concentration in the tailing. The abundances of meiofauna colonising defaunated controls and both tailing samples increased from zero to levels statistically indistinguishable from natural unaffected controls after 97 and 203days. Colonisation was well established in tailing from freshly mined ore after 40days, and in oxidized tailing from stockpiled ore after 65days, and was not dependent on settled natural material. PMID:19268316

  7. Individual-based model of bluegill sunfish production in aquatic mesocosms/microcosms

    SciTech Connect

    Florian, J.D. Jr.; Dixon, K.R.; DeAngelis, D.L.; Shaw, J.L.

    1994-12-31

    The development of an individual-based model for ag-ill sunfish, Lepomis macrochirus (Rafinesque) is described. Fish are modeled as an assemblage of individuals. Foraging, bioenergetics, interactions with conspecifics, and reproduction are modeled separately for each fish using control data from aquatic mesocosm/microcosm studies. The individual behavior of each fish is described by decision rules which specify what particular actions the fish performs on a daily basis. A summary of the most important behavioral rules for the model and how physical and resource environments can be taken into account is presented. Development of this type of modeling is pursued for ultimate use in field situations to better understand the influences of natural environmental conditions versus toxicant exposures on populations of fish through time.

  8. Effect of organic loading on nitrification and denitrification in a marine sediment microcosm

    USGS Publications Warehouse

    Caffrey, J.M.; Sloth, N.P.; Kaspar, H.F.; Blackburn, T.H.

    1993-01-01

    The effects of organic additions on nitrification and denitrification were examined in sediment microcosms. The organic material, heat killed yeast, had a C/N ratio of 7.5 and was added to sieved, homogenized sediments. Four treatments were compared: no addition (control, 30 g dry weight (dw) m-2 mixed throughout the 10 cm sediment column (30 M), 100 g dw m-2 mixed throughout sediments (100M), and 100 g dw m-2 mixed into top 1 cm (100S). After the microcosms had been established for 7-11 days, depth of O2 penetration, sediment-water fluxes and nitrification rates were measured. Nitrification rates were measured using three different techniques: N-serve and acetylene inhibition in intact cores, and nitrification potentials in slurries. Increased organic additions decreased O2 penetration from 2.7 to 0.2 mm while increasing both O2 consumption, from 30 to 70 mmol O2 m-2 d-1, and NO3- flux into sediments. Nitrification rates in intact cores were similar for the two methods. Highest rates occurred in the 30 M treatment, while the lowest rate was measured in the 100S treatment. Total denitrification rates (estimated from nitrification and nitrate fluxes) increased with increased organic addition, because of the high concentrations of NO3- (40 ??M) in the overlying water. The ratio of nitrification: denitrification was used as an indication of the importance of nitrification as the NO3- supply for denitrification. This ratio decreased from 1.55 to 0.05 with increased organic addition.

  9. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment.

    PubMed

    Tsiola, A; Pitta, P; Fodelianakis, S; Pete, R; Magiopoulos, I; Mara, P; Psarra, S; Tanaka, T; Mostajir, B

    2016-04-01

    The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores. PMID:26626911

  10. Net methylation of mercury in estuarine sediment microcosms amended with dissolved, nanoparticulate, and microparticulate mercuric sulfides.

    PubMed

    Zhang, Tong; Kucharzyk, Katarzyna H; Kim, Bojeong; Deshusses, Marc A; Hsu-Kim, Heileen

    2014-08-19

    The production of methylmercury (MeHg) by anaerobic microorganisms depends in part on the speciation and bioavailability of inorganic mercury to these organisms. Our previous work with pure cultures of methylating bacteria has demonstrated that the methylation potential of mercury decreased during the aging of mercuric sulfides (from dissolved to nanoparticulate and microcrystalline HgS). The objective of this study was to understand the relationship between mercury sulfide speciation and methylation potential in experiments that more closely simulate the complexity of sediment settings. The study involved sediment slurry microcosms that represented a spectrum of salinities in an estuary and were each amended with different forms of mercuric sulfides: dissolved Hg and sulfide, nanoparticulate HgS (3-4 nm in diameter), and microparticulate HgS (>500 nm). The results indicated that net MeHg production was influenced by both the activity of sulfate-reducing microorganisms (roughly represented by the rate of sulfate loss) and the bioavailability of mercury. In the presence of abundant sulfate and carbon sources (supporting relatively high microbial activity), net MeHg production in the slurries amended with dissolved Hg was greater than in slurries amended with nano-HgS, similar to previous experiments with pure bacterial cultures. In microcosms with minimal microbial activity (indicated by low rates of sulfate loss), the addition of either dissolved Hg or nano-HgS resulted in similar amounts of net MeHg production. For all slurries receiving micro-HgS, MeHg production did not exceed abiotic controls. In slurries amended with dissolved and nano-HgS, mercury was mainly partitioned to bulk-scale mineral particles and colloids, indicating that Hg bioavailability was not simply related to dissolved Hg concentration or speciation. Overall, the results suggest that models for mercury methylation potential in the environment will need to balance the relative contributions of

  11. The influence of fertilizer level and spore density on arbuscular mycorrhizal colonization of transgenic Bt 11 maize (Zea mays) in experimental microcosms.

    PubMed

    Cheeke, Tanya E; Pace, Brian A; Rosenstiel, Todd N; Cruzan, Mitchell B

    2011-02-01

    Crop plants genetically modified for the expression of Bacillus thuringiensis (Bt) insecticidal toxins have broad appeal for reducing insect damage in agricultural systems, yet questions remain about the impact of Bt plants on symbiotic soil organisms. Here, arbuscular mycorrhizal fungal (AMF) colonization of transgenic maize isoline Bt 11 (expressing Cry1Ab) and its non-Bt parental line (Providence) was evaluated under different fertilizer level and spore density scenarios. In a three-way factorial design, Bt 11 and non-Bt maize were inoculated with 0, 40, or 80 spores of Glomus mosseae and treated weekly with 'No' (0 g L(-1) ), 'Low' (0.23 g L(-1) ), or 'High' (1.87 g L(-1) ) levels of a complete fertilizer and grown for 60 days in a greenhouse. While no difference in AMF colonization was detected between the Bt 11 and Providence maize cultivars in the lower spore/higher fertilizer treatments, microcosm experiments demonstrated a significant reduction in AMF colonization in Bt 11 maize roots in the 80 spore treatments when fertilizer was limited. These results confirm previous work indicating an altered relationship between this Bt 11 maize isoline and AMF and demonstrate that the magnitude of this response is strongly dependent on both nutrient supply and AMF spore inoculation level. PMID:21198682

  12. [Research advances in denitrogenation characteristics of aerobic denitrifiers].

    PubMed

    Liang, Shu-Cheng; Zhao, Min; Lu, Lei; Zhao, Li-Yan

    2010-06-01

    The discovery of aerobic denitrifiers is the enrichment and breakthrough of traditional denitrification theory. Owing to their unique superiority in denitrogenation, aerobic denitrifiers have become a hotspot in the study of bio-denitrogenation of waste water. Under aerobic conditions, the aerobic denitrifiers can utilize organic carbon sources for their growth, and produce N2 from nitrate and nitrite. Most of the denitrifiers can also proceed with heterotrophic nitrification simultaneously, transforming NH4(+)-N to gaseous nitrogen. In this paper, the denitrogenation characteristics and action mechanisms of some isolated aerobic denitrifiers were discussed from the aspects of electron theory and denitrifying enzyme system. The effects of the environmental factors DO, carbon sources, and C/N on the denitrogenation process of aerobic denitrifiers were analyzed, and the screening methods as well as the present and potential applications of aerobic denitrifiers in wastewater treatment were described and discussed. PMID:20873638

  13. Aerobic workout and bone mass in females.

    PubMed

    Alfredson, H; Nordström, P; Lorentzon, R

    1997-12-01

    This cross-sectional study aimed to investigate bone mass in females participating in aerobic workout. Twenty-three females (age 24.1 +/- 2.7 years), participating in aerobic workout for about 3 hours/week, were compared with 23 age-, weight- and height-matched non-active females. Areal bone mineral density (BMD) was measured in total body, head, whole dominant humerus, lumbar spine, right femoral neck, Ward's triangle, trochanter femoris, in specific sites in right femur diaphysis, distal femur, proximal tibia and tibial diaphysis, and bone mineral content (BMC) was measured in the whole dominant arm and right leg, using dual energy X-ray absorptiometry. The aerobic workout group had significantly (P < 0.05-0.01) higher BMD in total body (3.7%), lumbar spine (7.8%), femoral neck (11.6%), Ward's triangle (11.7%), trochanter femoris (9.6%), proximal tibia (6.8%) and tibia diaphysis (5.9%) compared to the non-active controls. There were no differences between the groups concerning BMD of the whole dominant humerus, femoral diaphysis, distal femur and BMC and lean mass of the whole dominant arm and right leg. Leaness of the whole dominant arm and leg was correlated to BMC of the whole dominant arm and right leg in both groups. In young females, aerobic workout containing alternating high and low impact movements for the lower body is associated with a higher bone mass in clinically important sites like the lumbar spine and hip, but muscle strengthening exercises like push-ups and soft-glove boxing are not associated with a higher bone mass in the dominant humerus. It appears that there is a skeletal adaptation to the loads of the activity. PMID:9458499

  14. Impact of matric potential and pore size distribution on growth dynamics of filamentous and non-filamentous soil bacteria.

    PubMed

    Wolf, Alexandra B; Vos, Michiel; de Boer, Wietse; Kowalchuk, George A

    2013-01-01

    The filamentous growth form is an important strategy for soil microbes to bridge air-filled pores in unsaturated soils. In particular, fungi perform better than bacteria in soils during drought, a property that has been ascribed to the hyphal growth form of fungi. However, it is unknown if, and to what extent, filamentous bacteria may also display similar advantages over non-filamentous bacteria in soils with low hydraulic connectivity. In addition to allowing for microbial interactions and competition across connected micro-sites, water films also facilitate the motility of non-filamentous bacteria. To examine these issues, we constructed and characterized a series of quartz sand microcosms differing in matric potential and pore size distribution and, consequently, in connection of micro-habitats via water films. Our sand microcosms were used to examine the individual and competitive responses of a filamentous bacterium (Streptomyces atratus) and a motile rod-shaped bacterium (Bacillus weihenstephanensis) to differences in pore sizes and matric potential. The Bacillus strain had an initial advantage in all sand microcosms, which could be attributed to its faster growth rate. At later stages of the incubation, Streptomyces became dominant in microcosms with low connectivity (coarse pores and dry conditions). These data, combined with information on bacterial motility (expansion potential) across a range of pore-size and moisture conditions, suggest that, like their much larger fungal counterparts, filamentous bacteria also use this growth form to facilitate growth and expansion under conditions of low hydraulic conductivity. The sand microcosm system developed and used in this study allowed for precise manipulation of hydraulic properties and pore size distribution, thereby providing a useful approach for future examinations of how these properties influence the composition, diversity and function of soil-borne microbial communities. PMID:24391805

  15. Impact of Matric Potential and Pore Size Distribution on Growth Dynamics of Filamentous and Non-Filamentous Soil Bacteria

    PubMed Central

    Wolf, Alexandra B.; Vos, Michiel; de Boer, Wietse; Kowalchuk, George A.

    2013-01-01

    The filamentous growth form is an important strategy for soil microbes to bridge air-filled pores in unsaturated soils. In particular, fungi perform better than bacteria in soils during drought, a property that has been ascribed to the hyphal growth form of fungi. However, it is unknown if, and to what extent, filamentous bacteria may also display similar advantages over non-filamentous bacteria in soils with low hydraulic connectivity. In addition to allowing for microbial interactions and competition across connected micro-sites, water films also facilitate the motility of non-filamentous bacteria. To examine these issues, we constructed and characterized a series of quartz sand microcosms differing in matric potential and pore size distribution and, consequently, in connection of micro-habitats via water films. Our sand microcosms were used to examine the individual and competitive responses of a filamentous bacterium (Streptomyces atratus) and a motile rod-shaped bacterium (Bacillus weihenstephanensis) to differences in pore sizes and matric potential. The Bacillus strain had an initial advantage in all sand microcosms, which could be attributed to its faster growth rate. At later stages of the incubation, Streptomyces became dominant in microcosms with low connectivity (coarse pores and dry conditions). These data, combined with information on bacterial motility (expansion potential) across a range of pore-size and moisture conditions, suggest that, like their much larger fungal counterparts, filamentous bacteria also use this growth form to facilitate growth and expansion under conditions of low hydraulic conductivity. The sand microcosm system developed and used in this study allowed for precise manipulation of hydraulic properties and pore size distribution, thereby providing a useful approach for future examinations of how these properties influence the composition, diversity and function of soil-borne microbial communities. PMID:24391805

  16. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    PubMed

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product. PMID:26512862

  17. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%. PMID:17251012

  18. Evaluation of methyl fluoride and dimethyl ether as inhibitors of aerobic methane oxidation

    USGS Publications Warehouse

    Oremland, R.S.; Culbertson, C.W.

    1992-01-01

    Methyl fluoride (MF) and dimethyl ether (DME) were effective inhibitors of aerobic methanotrophy in a variety of soils. MF and DME blocked consumption of CH4 as well as the oxidation of 14CH4 to 14CO2, but neither MF nor DME affected the oxidation of [14C]methanol or [14C]formate to 14CO2. Cooxidation of ethane and propane by methane-oxidizing soils was also inhibited by MF. Nitrification (ammonia oxidation) in soils was inhibited by both MF and DME. Production of N2O via nitrification was inhibited by MF; however, MF did not affect N2O production associated with denitrification. Methanogenesis was partially inhibited by MF but not by DME. Methane oxidation was ~100-fold more sensitive to MF than was methanogenesis, indicating that an optimum concentration could be employed to selectively block methanotrophy. MF inhibited methane oxidation by cell suspensions of Methylococcus capsulatus; however, DME was a much less effective inhibitor.

  19. Clay mineral type effect on bacterial enteropathogen survival in soil.

    PubMed

    Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

    2014-01-15

    Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. PMID:24035982

  20. Multidisciplinary assessment of pesticide mitigation in soil amended with vermicomposted agroindustrial wastes.

    PubMed

    Castillo, Jean Manuel; Beguet, Jérèmie; Martin-Laurent, Fabrice; Romero, Esperanza

    2016-03-01

    Soil organic amendment affects biotic and abiotic processes that control the fate of pesticides, but the treatment history of the soil is also relevant. These processes were assessed in a multidisciplinary study with the aim of optimizing pesticide mitigation in soils. Soil microcosms pre-treated (E2) or not with diuron (E1) were amended with either winery (W) or olive waste (O) vermicomposts. Herbicide dissipation followed a double first-order model in E1 microcosms, but a single first-order model in E2. Also, diuron persistence was longer in E1 than in E2 (E1-DT50>200 day(-1), E2-DT50<16 day(-1)). The genetic structure of the bacterial community was modified by both diuron exposure and amendment. O-vermicompost increased enzymatic activities in both experiments, but diuron-degrading genetic potential (puhB) was quantified only in E2 microcosms in accordance with reduced diuron persistence. Therefore, O-vermicompost addition favoured the proliferation of diuron degraders, increasing the soil diuron-depuration capability. PMID:26590874

  1. In-situ Subaqueous Capping of Mercury-Contaminated Sediments in a Fresh-Water Aquatic System, Part I-Bench-Scale Microcosm Study to Assess Methylmercury Production

    EPA Science Inventory

    Bench-scale microcosm experiments were designed to provide a better understanding of the potential for Hg methylation in sediments from an aquatic environment. Experiments were conducted to examine the function of sulfate concentration, lactate concentration, the presence/absenc...

  2. Comparison between aerobic and anaerobic co-composting of agricultural residues.

    PubMed

    El Sebaie, O D; Hussin, A H; Shalaby, E E; Mohamed, M G; Lbrahem, M T

    2000-01-01

    Fertile soil is the most important resource for food production. The agricultural area in Egypt is limited to 6 million faddans. This limited area has derived many farmers to use several types of chemical fertilizers, to enhance the fertility of the land and hence the productivity. Excessive application of chemical fertilizer lead to the build up of these residuals because they are superfluous. This will cause waste of money and also soil pollution. Ultimately, this would adversely affect the ecological system in the soil and surrounding environment, especially water bodies. Composting of organic solid wastes will address some of the problems of solid waste disposal and gives a beneficial product which may replace the expensive chemical fertilizers. Other organic compostable solid wastes could be utilized to produce this compost. Agricultural residues are cheap raw materials for such compost and are available in vast quantities as well. This compost can be used as a soil conditioner to improve soil characteristics and its productivity. Crop residues mixed with manure, may be co-composted to give a soil conditioner. Agricultural residues, about 106 million tons/year, may produce about 55 million tons/year of compost. Three co-composting were carried out at the experimental station of the Faculty of Agriculture in Abis. Two aerobic co-composting of winter and summer crop residues and one anaerobic co-composting inter rop esidue were produced. The development of the co-composting processes controlled by the temperature, moisture content, and chemical composition was studied. The aerobic co-composting of winter crop residues was found to be the best experiment as it complied with the standards of the Ministry of Agriculture Decree No. 100/1967. This co-compost is expected to be free from pathogenic microorganisms as the dominant temperature was almost about 50 degrees C from the 42nd day till the 101st day of the experiment. PMID:17219853

  3. Watering, fertilization, and slurry inoculation promote recovery of biological crust function in degraded soils.

    PubMed

    Maestre, Fernando T; Martín, Noelia; Díez, Beatriz; López-Poma, Rosario; Santos, Fernando; Luque, Ignacio; Cortina, Jordi

    2006-10-01

    Biological soil crusts are very sensitive to human-induced disturbances and are in a degraded state in many areas throughout their range. Given their importance in the functioning of arid and semiarid ecosystems, restoring these crusts may contribute to the recovery of ecosystem functionality in degraded areas. We conducted a factorial microcosm experiment to evaluate the effects of inoculation type (discrete fragments vs slurry), fertilization (control vs addition of composted sewage sludge), and watering frequency (two vs five times per week) on the cyanobacterial composition, nitrogen fixation, chlorophyll content, and net CO2 exchange rate of biological soil crusts inoculated on a semiarid degraded soil from SE Spain. Six months after the inoculation, the highest rates of nitrogen fixation and chlorophyll a content were found when the biological crusts were inoculated as slurry, composted sewage sludge was added, and the microcosms were watered five times per week. Net CO2 exchange rate increased when biological crusts were inoculated as slurry and the microcosms were watered five times per week. Denaturing gradient gel electrophoresis fingerprints and phylogenetic analyses indicated that most of the cyanobacterial species already present in the inoculated crust had the capability to spread and colonize the surface of the surrounding soil. These analyses showed that cyanobacterial communities were less diverse when the microcosms were watered five times per week, and that watering frequency (followed in importance by the addition of composted sewage sludge and inoculation type) was the treatment that most strongly influenced their composition. Our results suggest that the inoculation of biological soil crusts in the form of slurry combined with the addition of composted sewage sludge could be a suitable technique to accelerate the recovery of the composition and functioning of biological soil crusts in drylands. PMID:16710791

  4. The emission of volatile compounds during the aerobic and the combined anaerobic/aerobic composting of biowaste

    NASA Astrophysics Data System (ADS)

    Smet, Erik; Van Langenhove, Herman; De Bo, Inge

    Two different biowaste composting techniques were compared with regard to their overall emission of volatile compounds during the active composting period. In the aerobic composting process, the biowaste was aerated during a 12-week period, while the combined anaerobic/aerobic composting process consisted of a sequence of a 3-week anaerobic digestion (phase I) and a 2-week aeration period (phase II). While the emission of volatiles during phase I of the combined anaerobic/aerobic composting process was measured in a full-scale composting plant, the aerobic stages of both composting techniques were performed in pilot-scale composting bins. Similar groups of volatile compounds were analysed in the biogas and the aerobic composting waste gases, being alcohols, carbonyl compounds, terpenes, esters, sulphur compounds and ethers. Predominance of alcohols (38% wt/wt of the cumulative emission) was observed in the exhaust air of the aerobic composting process, while predominance of terpenes (87%) and ammonia (93%) was observed in phases I and II of the combined anaerobic/aerobic composting process, respectively. In the aerobic composting process, 2-propanol, ethanol, acetone, limonene and ethyl acetate made up about 82% of the total volatile organic compounds (VOC)-emission. Next to this, the gas analysis during the aerobic composting process revealed a strong difference in emission profile as a function of time between different groups of volatiles. The total emission of VOC, NH 3 and H 2S during the aerobic composting process was 742 g ton -1 biowaste, while the total emission during phases I and II of the combined anaerobic/aerobic composting process was 236 and 44 g ton -1 biowaste, respectively. Taking into consideration the 99% removal efficiency of volatiles upon combustion of the biogas of phase I in the electricity generator, the combined anaerobic/aerobic composting process can be considered as an attractive alternative for aerobic biowaste composting because of

  5. Phylogenetically Distinct Phylotypes Modulate Nitrification in a Paddy Soil

    PubMed Central

    Zhao, Jun; Wang, Baozhan

    2015-01-01

    Paddy fields represent a unique ecosystem in which regular flooding occurs, allowing for rice cultivation. However, the taxonomic identity of the microbial functional guilds that catalyze soil nitrification remains poorly understood. In this study, we provide molecular evidence for distinctly different phylotypes of nitrifying communities in a neutral paddy soil using high-throughput pyrosequencing and DNA-based stable isotope probing (SIP). Following urea addition, the levels of soil nitrate increased significantly, accompanied by an increase in the abundance of the bacterial and archaeal amoA gene in microcosms subjected to SIP (SIP microcosms) during a 56-day incubation period. High-throughput fingerprints of the total 16S rRNA genes in SIP microcosms indicated that nitrification activity positively correlated with the abundance of Nitrosospira-like ammonia-oxidizing bacteria (AOB), soil group 1.1b-like ammonia-oxidizing archaea (AOA), and Nitrospira-like nitrite-oxidizing bacteria (NOB). Pyrosequencing of 13C-labeled DNA further revealed that 13CO2 was assimilated by these functional groups to a much greater extent than by marine group 1.1a-associated AOA and Nitrobacter-like NOB. Phylogenetic analysis demonstrated that active AOB communities were closely affiliated with Nitrosospira sp. strain L115 and the Nitrosospira multiformis lineage and that the 13C-labeled AOA were related to phylogenetically distinct groups, including the moderately thermophilic “Candidatus Nitrososphaera gargensis,” uncultured fosmid 29i4, and acidophilic “Candidatus Nitrosotalea devanaterra” lineages. These results suggest that a wide variety of microorganisms were involved in soil nitrification, implying physiological diversification of soil nitrifying communities that are constantly exposed to environmental fluctuations in paddy fields. PMID:25724959

  6. Phylogenetically distinct phylotypes modulate nitrification in a paddy soil.

    PubMed

    Zhao, Jun; Wang, Baozhan; Jia, Zhongjun

    2015-05-01

    Paddy fields represent a unique ecosystem in which regular flooding occurs, allowing for rice cultivation. However, the taxonomic identity of the microbial functional guilds that catalyze soil nitrification remains poorly understood. In this study, we provide molecular evidence for distinctly different phylotypes of nitrifying communities in a neutral paddy soil using high-throughput pyrosequencing and DNA-based stable isotope probing (SIP). Following urea addition, the levels of soil nitrate increased significantly, accompanied by an increase in the abundance of the bacterial and archaeal amoA gene in microcosms subjected to SIP (SIP microcosms) during a 56-day incubation period. High-throughput fingerprints of the total 16S rRNA genes in SIP microcosms indicated that nitrification activity positively correlated with the abundance of Nitrosospira-like ammonia-oxidizing bacteria (AOB), soil group 1.1b-like ammonia-oxidizing archaea (AOA), and Nitrospira-like nitrite-oxidizing bacteria (NOB). Pyrosequencing of 13C-labeled DNA further revealed that 13CO2 was assimilated by these functional groups to a much greater extent than by marine group 1.1a-associated AOA and Nitrobacter-like NOB. Phylogenetic analysis demonstrated that active AOB communities were closely affiliated with Nitrosospira sp. strain L115 and the Nitrosospira multiformis lineage and that the 13C-labeled AOA were related to phylogenetically distinct groups, including the moderately thermophilic "Candidatus Nitrososphaera gargensis," uncultured fosmid 29i4, and acidophilic "Candidatus Nitrosotalea devanaterra" lineages. These results suggest that a wide variety of microorganisms were involved in soil nitrification, implying physiological diversification of soil nitrifying communities that are constantly exposed to environmental fluctuations in paddy fields. PMID:25724959

  7. A Retrievable Mineral Microcosm for Examining Microbial Colonization and Mineral Precipitation at Seafloor Hydrothermal Vents

    NASA Astrophysics Data System (ADS)

    Dunn, E. E.; Holloway, J. R.; Cary, S.; Voglesonger, K. M.; Ashbridge, D. A.; O'Day, P. A.

    2002-12-01

    Although seafloor hydrothermal vent environments are known to support thriving ecosystems, the microscale physical and chemical environment suitable for microbial colonization and the identity of pioneering organisms is unknown. Because of the fragility of young chimneys and their ephemeral nature, novel methods for sample retrieval and analysis are required. The mineral microcosm consists of four titanium mesh chambers containing crushed minerals mounted on a titanium base that allows for fluid flow through the chambers. The chambers can be filled with different minerals or mineral mixtures (or no minerals) to supply different substrates for microbial colonization and different local microenvironments as minerals react with the surrounding fluids. The device sets on top of an active hydrothermal vent for a period of days to weeks to allow colonization and mineral reaction. The mineral microcosm was deployed during the Atlantis/Alvin Extreme 2001 Cruise (Oct.- Nov.,2001) to 9° 50'N on the East Pacific Rise a total of three times, for ~ 24, ~ 96, and ~ 48 hours each. It was deployed in two different environments, twice in lower temperature (<300°C), diffuse-flow environments and once (for ~96 hours) in a higher temperature black smoker environment (>350°C).Seed minerals included sulfides, sulfates, magnetite, apatite, and quartz, both individually and in mixtures. In the first 24-hour deployment, dissolution of anhydrite but not sulfide minerals within the chambers indicated high temperatures in chamber interiors and rapid reaction rates. Temperatures measured on chamber exteriors before retrieval ranged from 4° -98°C. The 96-hour deployment on a hot vent (fluid ~370°C before deployment) resulted in extensive mineral precipitation and chimney growth inside the mineral chambers, on the outer surfaces of the chambers, and on the platform as a whole, creating micro-chimneys several centimeters tall. The young chimneys were mainly composed of pyrite with lesser

  8. The aerobic and anaerobic bacteriology of perirectal abscesses.

    PubMed Central

    Brook, I; Frazier, E H

    1997-01-01

    The microbiology of perirectal abscesses in 144 patients was studied. Aerobic or facultative bacteria only were isolated in 13 (9%) instances, anaerobic bacteria only were isolated in 27 (19%) instances, and mixed aerobic and anaerobic flora were isolated in 104 (72%) instances. A total of 325 anaerobic and 131 aerobic or facultative isolates were recovered (2.2 anaerobic isolates and 0.9 aerobic isolates per specimen). The predominant anaerobes were as follows: Bacteroides fragilis group (85 isolates), Peptostreptococcus spp. (72 isolates), Prevotella spp. (71 isolates), Fusobacterium spp. (21 isolates), Porphyromonas spp. (20 isolates), and Clostridium spp. (15 isolates). The predominant aerobic and facultative bacteria were as follows: Staphylococcus aureus (34 isolates), Streptococcus spp. (28 isolates), and Escherichia coli (19 isolates). These data illustrate the polymicrobial aerobic and anaerobic microbiology of perirectal abscesses. PMID:9350771

  9. Ecotoxicological Impact of the Bioherbicide Leptospermone on the Microbial Community of Two Arable Soils.

    PubMed

    Romdhane, Sana; Devers-Lamrani, Marion; Barthelmebs, Lise; Calvayrac, Christophe; Bertrand, Cédric; Cooper, Jean-François; Dayan, Franck E; Martin-Laurent, Fabrice

    2016-01-01

    The ecotoxicological impact of leptospermone, a β-triketone bioherbicide, on the bacterial community of two arable soils was investigated. Soil microcosms were exposed to 0 × (control), 1 × or 10 × recommended dose of leptospermone. The β-triketone was moderately adsorbed to both soils (i.e.,: K fa ~ 1.2 and K oc ~ 140 mL g(-1)). Its dissipation was lower in sterilized than in unsterilized soils suggesting that it was mainly influenced by biotic factors. Within 45 days, leptospermone disappeared almost entirely from one of the two soils (i.e., DT50 < 10 days), while 25% remained in the other. The composition of the microbial community assessed by qPCR targeting 11 microbial groups was found to be significantly modified in soil microcosms exposed to leptospermone. Pyrosequencing of 16S rRNA gene amplicons showed a shift in the bacterial community structure and a significant impact of leptospermone on the diversity of the soil bacterial community. Changes in the composition, and in the α- and β-diversity of microbial community were transient in the soil able to fully dissipate the leptospermone, but were persistent in the soil where β-triketone remained. To conclude the bacterial community of the two soils was sensitive to leptospermone and its resilience was observed only when leptospermone was fully dissipated. PMID:27252691

  10. Ecotoxicological Impact of the Bioherbicide Leptospermone on the Microbial Community of Two Arable Soils

    PubMed Central

    Romdhane, Sana; Devers-Lamrani, Marion; Barthelmebs, Lise; Calvayrac, Christophe; Bertrand, Cédric; Cooper, Jean-François; Dayan, Franck E.; Martin-Laurent, Fabrice

    2016-01-01

    The ecotoxicological impact of leptospermone, a β-triketone bioherbicide, on the bacterial community of two arable soils was investigated. Soil microcosms were exposed to 0 × (control), 1 × or 10 × recommended dose of leptospermone. The β-triketone was moderately adsorbed to both soils (i.e.,: Kfa ~ 1.2 and Koc ~ 140 mL g−1). Its dissipation was lower in sterilized than in unsterilized soils suggesting that it was mainly influenced by biotic factors. Within 45 days, leptospermone disappeared almost entirely from one of the two soils (i.e., DT50 < 10 days), while 25% remained in the other. The composition of the microbial community assessed by qPCR targeting 11 microbial groups was found to be significantly modified in soil microcosms exposed to leptospermone. Pyrosequencing of 16S rRNA gene amplicons showed a shift in the bacterial community structure and a significant impact of leptospermone on the diversity of the soil bacterial community. Changes in the composition, and in the α- and β-diversity of microbial community were transient in the soil able to fully dissipate the leptospermone, but were persistent in the soil where β-triketone remained. To conclude the bacterial community of the two soils was sensitive to leptospermone and its resilience was observed only when leptospermone was fully dissipated. PMID:27252691

  11. Mineralization of hexachlorocyclohexane in soil during solid-phase bioremediation.

    PubMed

    Phillips, Theresa M; Lee, Hung; Trevors, Jack T; Seech, Alan G

    2004-06-01

    Soil containing hexachlorocyclohexane (HCH) was spiked with (14)C-gamma-HCH and then subjected to bioremediation in bench-scale microcosms to determine the rate and extent of mineralization of the (14)C-labeled HCH to (14)CO(2). The soil was treated using two different DARAMEND amendments, D6386 and D6390. The amendments were previously found to enhance natural HCH bioremediation as determined by measuring the disappearance of parent compounds under either strictly oxic conditions (D6386), or cycled anoxic/oxic conditions (D6390). Within 80 days of the initiation of treatment, mineralization was observed in all of the strictly oxic microcosms. However, mineralization was negligible in the cycled anoxic/oxic microcosms throughout the 275-day study, even after cycling was ceased at 84 days and although significant removal (up to 51%) of indigenous gamma-HCH (146 mg/kg) was detected by GC with electron capture detector. Of the amended, strictly oxic treatments, only one, in which 47% of the spiked (14)C-HCH was recovered as (14)CO(2), enhanced mineralization compared with an unamended treatment (in which 34% recovery was measured). Other oxic treatments involving higher amendment application rates or auxiliary carbon sources were inhibitory to mineralization. Thus, although HCH degradation occurs during the application of either oxic or cycled anoxic/oxic DARAMEND treatments, mineralization of gamma-HCH may be inhibited depending on the amendment and treatment protocol. PMID:15221667

  12. The MICROBE (Microcosm Investigation of Carbonate Reef/Ocean Microbial Biogeochemistry & Ecology) Project

    NASA Astrophysics Data System (ADS)

    Hannides, A. K.; Gaidos, E. J.; Sansone, F. J.

    2003-12-01

    We present a methodology to manipulate carbonate reef sediments in order to study the geochemical and microbiological response of reef systems to perturbations. We specifically plan to study the effects of changes in the atmospheric partial pressure of CO2. Our laboratory set-up will consist of cores containing carbonate reef sediments and overlying water. These microcosms are designed to replicate the gross hydraulic and geochemical characteristics of sediments in a natural tropical reef patch. This is achieved by reproducing the advective transport of water and particulates in and out of the sediments induced by tides and surface waves. Seawater from nearby reefs is to be introduced into the cores with reversible peristaltic pumps. The pumps will vary the overlying water column and simulate the changes in hydrostatic head that accompany waves and tides. The parameters characterizing these oscillations will be set at values reflecting those at nearby natural settings. Sediment column characteristics will be determined non-destructively through openings at various depths down the sediment cores. These openings are fitted with rubber septa and shut-off valves, which allow gas-tight sampling of porewaters. An additional set of openings allows for the removal of small amounts of sediments using augers. Our porewater analyses will include dissolved O2, CO2, CH4 and alkalinity, ammonium, sulfide, and iron and manganese ions. Our solid phase analyses will include carbonate composition and framework structure, and iron and manganese abundances in the carbonate phases. We will measure microbial abundance in porewater and the sediment particles by DAPI cell counts and will assay community composition using Denaturing Gradient Gel Electrophoresis (DGGE). Our goal is to use this methodology to observe and record carbonate precipitation and dissolution by microbiota under varying carbon dioxide regimes. pCO2 concentrations will be manipulated by bubbling a N2/CO2 mixture

  13. Synergy in microcosms with environmentally realistic concentrations of prochloraz and esfenvalerate.

    PubMed

    Bjergager, Maj-Britt A; Hanson, Mark L; Lissemore, Linda; Henriquez, Nikki; Solomon, Keith R; Cedergreen, Nina

    2011-01-25

    Laboratory experiments have shown that azole fungicides enhance the toxic effect of pyrethroid insecticides towards the aquatic crustacean Daphnia magna. Due to their sorptive properties the pesticides may, however, be less bioavailable in natural environments, possibly rendering them less toxic to aquatic organisms. In the present study, the synergistic potential of azoles on pyrethroids in natural environments was assessed by treating 18 outdoor aquatic microcosms with concentrations of the pyrethroid esfenvalerate at 0.167, 0.333, or 0.833μg/L either alone or in combination with 90μg/L of the azole prochloraz. Pesticide concentrations and the zooplankton and phytoplankton communities were assessed prior to pesticide application and at days 0, 1, 2, 4, 7, 14, 21, and 28 after pesticide application. DT(50)-values for disappearance of the pesticides from the water of 4.7 days and 30h were observed for prochloraz and esfenvalerate, respectively. The monitored communities showed larger decreases in abundance of cladoceran, copepods, and chironomids in treatments with esfenvalerate in combination with prochloraz compared to treatments with esfenvalerate alone. No systematic effects were observed in populations of Ostracoda. Adverse effects on populations of cladocerans and copepods occurred between day 2 and day 7 and, though copepods in general were less sensitive than cladocerans to both esfenvalerate alone and in combination with prochloraz, the potentiation factors for the two taxa were similar. Thus, comparison of EC(20)-values estimated on the basis of concentration-response curves for days 2, 4, and 7 showed that prochloraz enhanced the toxicity of esfenvalerate four to sixfold for copepods and three to sevenfold for cladocerans. Rotifers were not significantly affected by any of the treatments, though there was a tendency of a population increase when cladoceran and copepod populations decreased. In all invertebrate populations that showed response to the

  14. Microbial Community Phylogenetic and Functional Succession in Chromium-Reducing Aquifer-Derived Microcosms

    NASA Astrophysics Data System (ADS)

    Brodie, E. L.; Beller, H. R.; Goldfarb, K. C.; Han, R.; Santee, C. A.

    2009-12-01

    In situ reductive immobilization, whereby highly soluble Cr(VI) species are reduced to poorly soluble Cr(III) species, is a favored approach for remediating Cr-contaminated groundwater. How microbial populations respond phylogenetically and functionally to the injection of an organic electron donor to stimulate Cr(VI) reduction is unclear, as are the relative contributions of direct enzymatic Cr(VI) reduction versus indirect (e.g. sulfide-mediated) reduction. In this study, we inoculated anaerobic microcosms with groundwater from the Cr-contaminated Hanford 100H site (WA) and supplemented them with lactate and the electron acceptors nitrate, sulfate, and amorphous ferric oxyhydroxide. The microcosms progressed successively through nitrate-reducing, sulfate-reducing, and Fe(III)-reducing conditions, and after a second nitrate amendment, nitrate-dependent Fe(II)-oxidizing conditions. Cr(VI) reduction occurred during both the denitrification and the sulfate/iron reduction phases. DNA and RNA were harvested during each major biogeochemical phase and were subjected to PhyloChip analysis, qPCR, and transcript sequencing. Bacterial community succession followed a trajectory related to the sequential use of electron acceptors. During denitrification, bacterial communities were enriched in known denitrifiers within the Beta- and Gamma-proteobacteria and became phylogenetically clustered. Fermenters became enriched following nitrate reduction, preceding both iron and sulfate reduction. Iron reduction was stoichiometrically related to the formation of hydrogen sulfide and, although iron reducers were detected during this phase, their iron-reducing activity was not confirmed. Following the depletion of lactate and sulfate, iron reduction rates decreased and acetate and propionate concentrations stabilized, indicating a marginal contribution of acetate-coupled iron reduction. Rapid Fe(II) oxidation occurred following the nitrate amendment with a concomitant reduction of nitrate

  15. EFFECTS OF A LIGNIN PEROXIDASE-EXPRESSING RECOMBINANT STREPTOMYCES LIVIDANS TK23.1 ON BIOGEOCHEMICAL CYCLING AND THE NUMBERS AND ACTIVITIES OF MICROORGANISMS IN SOIL

    EPA Science Inventory

    A recombinant actinomycete, Streptomyces lividans TK23.1, expressing a pIJ702-encoded extracellular lignin peroxidase gene cloned from the chromosome of Streptomyces virodosporus T7A, was released into soil in flask- and microcosm-scale studies to determine its effects on humific...

  16. Substrate interaction during aerobic biodegradation of creosote-related compounds in columns of sandy aquifer material

    NASA Astrophysics Data System (ADS)

    Millette, Denis; Butler, Barbara J.; Frind, E. O.; Comeau, Yves; Samon, Réjean

    1998-01-01

    A column study was initiated to study the effect of phenanthrene, fluorene, and p-cresol on the aerobic biodegradation of carbazole in columns of sandy aquifer material. Biodegradation of the contaminant mixture was sequential in space with p-cresol being preferentially degraded, followed by phenanthrene, then the other compounds. Both p-cresol and phenanthrene were completely biotransformed to non-detectable levels during passage through the 46 cm sand column but some carbazole and fluorene persisted throughout the approximately 3 month experiments. Influent p-cresol (10000ppb) was the only compound that affected adaptation of the microbial community to carbazole biodegradation, but its effect was of little practical importance, amounting to a 4.5 day difference in carbazole breakthrough. However, when influent p-cresol was at high levels (70 000 ppb), biotransformation of the other co-substrates in the mixture never ensued because p-cresol caused complete dissolved oxygen depletion. Conversely, influent p-cresol ultimately enhanced biotransformation of the other co-substrates in the mixture when present at a concentration (10000ppb) that did not deplete all available oxygen. The concentrations of the other, more recalcitrant compounds, ranging between 33 and 238 ppb, were probably too low to support bacterial growth so that slow, limited biotransformation resulted, although addition of an auxiliary substrate (i.e. the p-cresol) stimulated their biotransformation. Under quasi-steady-state conditions, the presence of phenanthrene in the influent inhibited fluorene biotransformation and possibly carbazole biotransformation. Results of the present study demonstrated also that interactions identified in static batch microcosms and in a hydrodynamic saturated column system can differ.

  17. 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

  18. One millimetre makes the difference: high-resolution analysis of methane-oxidizing bacteria and their specific activity at the oxic–anoxic interface in a flooded paddy soil

    PubMed Central

    Reim, Andreas; Lüke, Claudia; Krause, Sascha; Pratscher, Jennifer; Frenzel, Peter

    2012-01-01

    Aerobic methane-oxidizing bacteria (MOB) use a restricted substrate range, yet >30 species-equivalent operational taxonomical units (OTUs) are found in one paddy soil. How these OTUs physically share their microhabitat is unknown. Here we highly resolved the vertical distribution of MOB and their activity. Using microcosms and cryosectioning, we sub-sampled the top 3-mm of a water-saturated soil at near in situ conditions in 100-μm steps. We assessed the community structure and activity using the particulate methane monooxygenase gene pmoA as a functional and phylogenetic marker by terminal restriction fragment length polymorphism (t-RFLP), a pmoA-specific diagnostic microarray, and cloning and sequencing. pmoA genes and transcripts were quantified using competitive reverse transcriptase PCR combined with t-RFLP. Only a subset of the methanotroph community was active. Oxygen microprofiles showed that 89% of total respiration was confined to a 0.67-mm-thick zone immediately above the oxic–anoxic interface, most probably driven by methane oxidation. In this zone, a Methylobacter-affiliated OTU was highly active with up to 18 pmoA transcripts per cell and seemed to be adapted to oxygen and methane concentrations in the micromolar range. Analysis of transcripts with a pmoA-specific microarray found a Methylosarcina-affiliated OTU associated with the surface zone. High oxygen but only nanomolar methane concentrations at the surface suggested an adaptation of this OTU to oligotrophic conditions. No transcripts of type II methanotrophs (Methylosinus, Methylocystis) were found, which indicated that this group was represented by resting stages only. Hence, different OTUs within a single guild shared the same microenvironment and exploited different niches. PMID:22695859

  19. Identification of transformation products from β-blocking agents formed in wetland microcosms using LC-Q-ToF.

    PubMed

    Svan, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Jasper, Justin T; Sedlak, David L; Pettersson, Curt E

    2016-03-01

    Identification of degradation products from trace organic compounds, which may retain the biological activity of the parent compound, is an important step in understanding the long-term effects of these compounds on the environment. Constructed wetlands have been successfully utilized to remove contaminants from wastewater effluent, including pharmacologically active compounds. However, relatively little is known about the transformation products formed during wetland treatment. In this study, three different wetland microcosm treatments were used to determine the biotransformation products of the β-adrenoreceptor antagonists atenolol, metoprolol and propranolol. LC/ESI-Q-ToF run in the MS(E) and MS/MS modes was used to identify and characterize the degradation products through the accurate masses of precursor and product ions. The results were compared with those of a reference standard when available. Several compounds not previously described as biotransformation products produced in wetlands were identified, including propranolol-O-sulfate, 1-naphthol and the human metabolite N-deaminated metoprolol. Transformation pathways were significantly affected by microcosm conditions and differed between compounds, despite the compounds' structural similarities. Altogether, a diverse range of transformation products in wetland microcosms were identified and elucidated using high resolving MS. This work shows that transformation products are not always easily predicted, nor formed via the same pathways even for structurally similar compounds. PMID:26956388

  20. Effect of organic amendment and plant roots on the solubility and mobilization of lead in soils at a shooting range.

    PubMed

    Levonmäki, M; Hartikainen, H; Kairesalo, T

    2006-01-01

    Lead (Pb) dissolving gradually from spent pellets constitutes a serious environmental risk in and near shooting ranges, and remediation measures are necessary to prevent its movement to deeper soil layers and ground water. In this study, the effectiveness of organic amendment and plant roots in stabilizing Pb was assessed in a microcosm experiment. Planted (Scots pine, Pinus sylvestris L.) and unplanted microcosms consisting of coarse-textured mineral soil covered with Pb-contaminated humic topsoil were coated with uncontaminated peat layers of 1 to 3 cm and incubated for 77 d. In a percolation test, the microcosms were washed with ultra pure water to simulate heavy rain so as to rinse water-soluble lead (Pbw) from the topsoil layer. Although Pbw remained below detection limits in the mineral soils in all test units, acid-soluble lead (Pba) increased. Peat amendment diminished Pba in the mineral soil layer, this effect being more pronounced in planted soils, indicating that Pb was taken up by the plants. The percolation test showed that the effect of Scots pine seedlings on Pb movement was minor when peat was added. A long-term dissolution test revealed that considerably more Pb was released from old pellets into soil extracts than from new ones, whereas only traces of Pb, if any, were dissolved in sterilized pure water. PMID:16738387

  1. Sequence-Based Identification of Aerobic Actinomycetes

    PubMed Central

    Patel, Jean Baldus; Wallace, Richard J.; Brown-Elliott, Barbara A.; Taylor, Tony; Imperatrice, Carol; Leonard, Deborah G. B.; Wilson, Rebecca W.; Mann, Linda; Jost, Kenneth C.; Nachamkin, Irving

    2004-01-01

    We investigated the utility of 500-bp 16S rRNA gene sequencing for identifying clinically significant species of aerobic actinomycetes. A total of 28 reference strains and 71 clinical isolates that included members of the genera Streptomyces, Gordonia, and Tsukamurella and 10 taxa of Nocardia were studied. Methods of nonsequencing analyses included growth and biochemical analysis, PCR-restriction enzyme analysis of the 439-bp Telenti fragment of the 65 hsp gene, susceptibility testing, and, for selected isolates, high-performance liquid chromatography. Many of the isolates were included in prior taxonomic studies. Sequencing of Nocardia species revealed that members of the group were generally most closely related to the American Type Culture Collection (ATCC) type strains. However, the sequences of Nocardia transvalensis, N. otitidiscaviarum, and N. nova isolates were highly variable; and it is likely that each of these species contains multiple species. We propose that these three species be designated complexes until they are more taxonomically defined. The sequences of several taxa did not match any recognized species. Among other aerobic actinomycetes, each group most closely resembled the associated reference strain, but with some divergence. The study demonstrates the ability of partial 16S rRNA gene sequencing to identify members of the aerobic actinomycetes, but the study also shows that a high degree of sequence divergence exists within many species and that many taxa within the Nocardia spp. are unnamed at present. A major unresolved issue is the type strain of N. asteroides, as the present one (ATCC 19247), chosen before the availability of molecular analysis, does not represent any of the common taxa associated with clinical nocardiosis. PMID:15184431

  2. Simultaneous biodegradation of carbon tetrachloride and trichloroethylene in a coupled anaerobic/aerobic biobarrier.

    PubMed

    Kwon, Kiwook; Shim, Hojae; Bae, Wookeun; Oh, Juhyun; Bae, Jisu

    2016-08-01

    Simultaneous biodegradation of carbon tetrachloride (CT) and trichloroethylene (TCE) in a biobarrier with polyethylene glycol (PEG) carriers was studied. Toluene/methanol and hydrogen peroxide (H2O2) were used as electron donors and an electron acceptor source, respectively, in order to develop a biologically active zone. The average removal efficiencies for TCE and toluene were over 99.3%, leaving the respective residual concentrations of ∼12 and ∼57μg/L, which are below or close to the groundwater quality standards. The removal efficiency for CT was ∼98.1%, with its residual concentration (65.8μg/L) slightly over the standards. TCE was aerobically cometabolized with toluene as substrate while CT was anaerobically dechlorinated in the presence of electron donors, with the respective stoichiometric amount of chloride released. The oxygen supply at equivalent to 50% chemical oxygen demand of the injected electron donors supported successful toluene oxidation and also allowed local anaerobic environments for CT reduction. The originally augmented (immobilized in PEG carriers) aerobic microbes were gradually outcompeted in obtaining substrate and oxygen. Instead, newly developed biofilms originated from indigenous microbes in soil adapted to the coupled anaerobic/aerobic environment in the carrier for the simultaneous and almost complete removal of CT, TCE, and toluene. The declined removal rates when temperature fell from 28 to 18°C were recovered by doubling the retention time (7.2 days). PMID:27054665

  3. BIOLOGICAL AMENDMENTS AND CROP ROTATIONS FOR MANAGING SOIL MICROBIAL COMMUNITIES AND SOILBORNE DISEASES OF POTATO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various biological amendments, including commercial biocontrol agents, microbial inoculants, mycorrhizae, and an aerobic compost tea (CT), were evaluated, alone and in conjunction with different crop rotations, for their efficacy in introducing beneficial microorganisms, affecting soil microbial com...

  4. Aerobic degradation of olive mill wastewaters.

    PubMed

    Benitez, J; Beltran-Heredia, J; Torregrosa, J; Acero, J L; Cercas, V

    1997-02-01

    The degradation of olive mill wastewater by aerobic microorganisms has been investigated in a batch reactor, by conducting experiments where the initial concentration of organic matter, quantified by the chemical oxygen demand, and the initial biomass were varied. The evolution of the chemical oxygen demand, biomass and the total contents of phenolic and aromatic compounds were followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic constants are evaluated. This final predicted equation agrees well with all the experimental data. PMID:9077005