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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. Agar-block microcosms for controlled plant tissue decomposition by aerobic fungi.

    PubMed

    Schilling, Jonathan S; Jacobson, K Brook

    2011-02-03

    The two principal methods for studying fungal biodegradation of lignocellulosic plant tissues were developed for wood preservative testing (soil-block; agar-block). It is well-accepted that soil-block microcosms yield higher decay rates, fewer moisture issues, lower variability among studies, and higher thresholds of preservative toxicity. Soil-block testing is thus the more utilized technique and has been standardized by American Society for Testing and Materials (ASTM) (method D 1413-07). The soil-block design has drawbacks, however, using locally-variable soil sources and in limiting the control of nutrients external (exogenous) to the decaying tissues. These drawbacks have emerged as a problem in applying this method to other, increasingly popular research aims. These modern aims include degrading lignocellulosics for bioenergy research, testing bioremediation of co-metabolized toxics, evaluating oxidative mechanisms, and tracking translocated elements along hyphal networks. Soil-blocks do not lend enough control in these applications. A refined agar-block approach is necessary. Here, we use the brown rot wood-degrading fungus Serpula lacrymans to degrade wood in agar-block microcosms, using deep Petri dishes with low-calcium agar. We test the role of exogenous gypsum on decay in a time-series, to demonstrate the utility and expected variability. Blocks from a single board rip (longitudinal cut) are conditioned, weighed, autoclaved, and introduced aseptically atop plastic mesh. Fungal inoculations are at each block face, with exogenous gypsum added at interfaces. Harvests are aseptic until the final destructive harvest. These microcosms are designed to avoid block contact with agar or Petri dish walls. Condensation is minimized during plate pours and during incubation. Finally, inoculum/gypsum/wood spacing is minimized but without allowing contact. These less technical aspects of agar-block design are also the most common causes of failure and the key source of

  3. 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.

  4. 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

  5. Petroleum hydrocarbon bioventing kinetics determined in soil core, microcosm, and tubing cluster studies

    SciTech Connect

    Moyer, E.E.; Ostendorf, D.W.; Richards, R.J.; Goodwin, S.

    1996-05-01

    Aerobic biodegradation of vapor-phase petroleum hydrocarbons was evaluated in an intact soil core from the site of an aviation gasoline release. An unsaturated zone soil core was subjected to a flow of nitrogen gas, oxygen, water vapor, and vapor-phase hydrocarbons in a configuration analogous to a biofilter or an in situ bioventing or sparging situation. The vertical profiles of vapor-phase hydrocarbon concentration in the soil core were determined by gas chromatography of vapor samples. Biodegradation reduced low influent hydrocarbon concentrations by 45 to 92% over a 0.6-m interval of an intact soil core. The estimated total hydrocarbon concentration was reduced by 75% from 26 to 7 parts per million. Steady-state concentrations were input to a simple analytical model balancing advection and first-order biodegradation of hydrocarbons. First-order rate constants for the major hydrocarbon compounds were used to calibrate the model to the concentration profiles. Rate constants for the seven individual hydrocarbon compounds varied by a factor of 4. Compounds with lower molecular weights, fewer methyl groups, and no quaternary carbons tended to have higher rate constants. The first-order rate constants were consistent with kinetic parameters determined from both microcosm and tubing cluster studies at the field site.

  6. 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.

  7. Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.

    PubMed

    Salminen, J; Liiri, M; Haimi, J

    2002-09-01

    Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were analyzed. Soil respiration measurements from the microcosms appeared to be a sensitive parameter for testing community-level effects of chemicals in the soil with high organic matter content. An 84-day exposure had acute effects, long-term effects, delaying effects, and total recovery of community respiration. Direct negative and indirect positive effects of chemical contamination on the community of soil organisms were found. Responses to contamination of soil respiration rate and structure of the soil community were parallel. Addition of pentachlorophenol, 2-ethanolhexane, and Cu into the soil reduced frost resistance of the decomposer community. It was concluded that soil respiration monitoring of artificially contaminated soil microcosms seems to be a useful tool for testing community-level toxic effects of chemicals.

  8. 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

  9. 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

  10. Dynamics of microbial community during bioremediation of phenanthrene and chromium(VI)-contaminated soil microcosms.

    PubMed

    Ibarrolaza, Agustín; Coppotelli, Bibiana M; Del Panno, María T; Donati, Edgardo R; Morelli, Irma S

    2009-02-01

    The combined effect of phenanthrene and Cr(VI) on soil microbial activity, community composition and on the efficiency of bioremediation processes has been studied. Biometer flask systems and soil microcosm systems contaminated with 2,000 mg of phenanthrene per kg of dry soil and different Cr(VI) concentrations were investigated. Temperature, soil moisture and oxygen availability were controlled to support bioremediation. Cr(VI) inhibited the phenanthrene mineralization (CO(2) production) and cultivable PAH degrading bacteria at levels of 500-2,600 mg kg(-1). In the bioremediation experiments in soil microcosms the degradation of phenanthrene, the dehydrogenase activity and the increase in PAH degrading bacteria counts were retarded by the presence of Cr(VI) at all studied concentrations (25, 50 and 100 mg kg(-1)). These negative effects did not show a correlation with Cr(VI) concentration. Whereas the presence of Cr(VI) had a negative effect on the phenanthrene elimination rate, co-contamination with phenanthrene reduced the residual Cr(VI) concentration in the water exchangeable Cr(VI) fraction (WEF) in comparison with the soil microcosm contaminated only with Cr(VI). Clear differences were found between the denaturing gradient gel electrophoresis (DGGE) patterns of each soil microcosm, showing that the presence of different Cr(VI) concentrations did modulate the community response to phenanthrene and caused perdurable changes in the structure of the microbial soil community.

  11. 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.

  12. Effects of randomly methylated-beta-cyclodextrins (RAMEB) on the bioavailability and aerobic biodegradation of polychlorinated biphenyls in three pristine soils spiked with a transformer oil.

    PubMed

    Fava, F; Ciccotosto, V F

    2002-03-01

    The low bioavailability of polychlorinated biphenyls (PCBs) in soils often results in their slow and partial aerobic biodegradation. The process can be enhanced by supplementing soils with cyclodextrins. However, pure cyclodextrins are expensive and we have therefore explored the use of a less costly technical grade mixture of randomly methylated-beta-cyclodextrins (RAMEB). RAMEB was tested at 0, 1, 3 and 5% (w/w) in the aerobic bioremediation and detoxification of a loamy-, a humic- and a sandy-soil, each artificially contaminated with a PCB-containing transformer oil (added PCBs: about 450 or 700 mg/kg), inoculated with an exogenous aerobic PCB-biodegrading bacterial co-culture and treated in slurry- and solid-phase laboratory conditions. Significant depletions of the spiked PCBs were observed in all microcosms of the three soils after 90 days of treatment; however, interesting yields of PCB dechlorination and detectable decreases of the original soil ecotoxicity were observed in the slurry-phase microcosms. RAMEB generally enhanced PCB-metabolism with effects which were dependent on the concentration at which it was applied, the physical-chemical nature of the amended soil, and the soil treatment conditions employed. RAMEB, which was slowly metabolized by soil microorganisms, enhanced the presence of PCBs and PCB-cometabolizing bacteria in the soil-water phase, suggesting that RAMEB enhances aerobic biodegradation of PCBs by increasing pollutant bioavailability in soil microcosms.

  13. 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.

  14. Growth of ammonia-oxidizing archaea in soil microcosms is inhibited by acetylene.

    PubMed

    Offre, Pierre; Prosser, James I; Nicol, Graeme W

    2009-10-01

    Autotrophic ammonia-oxidizing bacteria were considered to be responsible for the majority of ammonia oxidation in soil until the recent discovery of the autotrophic ammonia-oxidizing archaea. To assess the relative contributions of bacterial and archaeal ammonia oxidizers to soil ammonia oxidation, their growth was analysed during active nitrification in soil microcosms incubated for 30 days at 30 degrees C, and the effect of an inhibitor of ammonia oxidation (acetylene) on their growth and soil nitrification kinetics was determined. Denaturing gradient gel electrophoresis (DGGE) analysis of bacterial ammonia oxidizer 16S rRNA genes did not detect any change in their community composition during incubation, and quantitative PCR (qPCR) analysis of bacterial amoA genes indicated a small decrease in abundance in control and acetylene-containing microcosms. DGGE fingerprints of archaeal amoA and 16S rRNA genes demonstrated changes in the relative abundance of specific crenarchaeal phylotypes during active nitrification. Growth was also indicated by increases in crenarchaeal amoA gene copy number, determined by qPCR. In microcosms containing acetylene, nitrification and growth of the crenarchaeal phylotypes were suppressed, suggesting that these crenarchaea are ammonia oxidizers. Growth of only archaeal but not bacterial ammonia oxidizers occurred in microcosms with active nitrification, indicating that ammonia oxidation was mostly due to archaea in the conditions of the present study.

  15. Capacity for Methane Oxidation in Landfill Cover Soils Measured in Laboratory-Scale Soil Microcosms

    PubMed Central

    Kightley, D.; Nedwell, D. B.; Cooper, M.

    1995-01-01

    Laboratory-scale soil microcosms containing different soils were permeated with CH(inf4) for up to 6 months to investigate their capacity to develop a methanotrophic community. Methane emissions were monitored continuously until steady states were established. The porous, coarse sand soil developed the greatest methanotrophic capacity (10.4 mol of CH(inf4) (middot) m(sup-2) (middot) day(sup-1)), the greatest yet reported in the literature. Vertical profiles of O(inf2), CH(inf4), and methanotrophic potential in the soils were determined at steady state. Methane oxidation potentials were greatest where the vertical profiles of O(inf2) and CH(inf4) overlapped. A significant increase in the organic matter content of the soil, presumably derived from methanotroph biomass, occurred where CH(inf4) oxidation was greatest. Methane oxidation kinetics showed that a soil community with a low methanotrophic capacity (V(infmax) of 258 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) but relatively high affinity (k(infapp) of 1.6 (mu)M) remained in N(inf2)-purged control microcosms, even after 6 months without CH(inf4). We attribute this to a facultative, possibly mixotrophic, methanotrophic microbial community. When purged with CH(inf4), a different methanotrophic community developed which had a lower affinity (k(infapp) of 31.7 (mu)M) for CH(inf4) but a greater capacity (V(infmax) of 998 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) for CH(inf4) oxidation, reflecting the enrichment of an active high-capacity methanotrophic community. Compared with the unamended control soil, amendment of the coarse sand with sewage sludge enhanced CH(inf4) oxidation capacity by 26%; K(inf2)HPO(inf4) amendment had no significant effect, while amendment with NH(inf4)NO(inf3) reduced the CH(inf4) oxidation capacity by 64%. In vitro experiments suggested that NH(inf4)NO(inf3) additions (10 and 71 (mu)mol (middot) g of soil(sup-1)) inhibited CH(inf4) oxidation by a nonspecific ionic effect

  16. 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.

  17. Monitoring of soil bacterial community and some inoculated bacteria after prescribed fire in microcosm.

    PubMed

    Song, Hong-Gyu; Kim, Ok-Sun; Yoo, Jae-Jun; Jeon, Sun-Ok; Hong, Sun-Hee; Lee, Dong-Hun; Ahn, Tae-Seok

    2004-12-01

    The soil bacterial community and some inoculated bacteria were monitored to assess the microbial responses to prescribed fire in their microcosm. An acridine orange direct count of the bacteria in the unburned control soil were maintained at a relatively stable level (2.0 approximately 2.7 x 10(9) cells/g(-1).soil) during the 180 day study period. The number of bacteria in the surface soil was decreased by fire, but was restored after 3 months. Inoculation of some bacteria increased the number of inoculated bacteria several times and these elevated levels lasted several months. The ratios of eubacteria detected by a fluorescent in situ hybridization (FISH) method to direct bacterial count were in the range of 60 approximately 80% during the study period, with the exception of some lower values at the beginning, but there were no definite differences between the burned and unburned soils or the inoculated and uninoculated soils. In the unburned control soil, the ratios of alpha-, beta- and gamma-subgroups of the proteobacteria, Cytophaga-Flavobacterium and other eubacteria groups to that of the entire eubacteria were 13.7, 31.7, 17.1, 16.8 and 20.8%, respectively, at time 0. The overall change on the patterns of the ratios of the 5 subgroups of eubacteria in the uninoculated burned and inoculated soils were similar to those of the unburned control soil, with the exception of some minor variations during the initial period. The proportions of each group of eubacteria became similar in the different microcosms after 6 months, which may indicate the recovery of the original soil microbial community structure after fire or the inoculation of some bacteria. The populations of Azotobacter vinelandii, Bacillus megaterium and Pseudomonas fluorescens, which had been inoculated to enhance the microbial activities, and monitored by FISH method, showed similar changes in the microcosms, and maintained high levels for several months.

  18. A microcosm system and an analytical protocol to assess PAH degradation and metabolite formation in soils.

    PubMed

    Arias, Lida; Bauzá, Jorge; Tobella, Joana; Vila, Joaquim; Grifoll, Magdalena

    2008-06-01

    During bioremediation of polycyclic aromatic hydrocarbon (PAH)-polluted soils accumulation of polar metabolites resulting from the biological activity may occur. Since these polar metabolites are potentially more toxic than the parental products, a better understanding of the processes involved in the production and fate of these oxidation products in soil is needed. In the present work we describe the design and set-up of a static soil microcosm system and an analytical methodology for detection of PAHs and their oxidation products in soils. When applied to a soil contaminated with phenanthrene, as a model PAH, and 1-hydroxy-2-naphthoic acid, diphenic acid, and phthalic acid as putative metabolites, the extraction and fractionation procedures resulted in recoveries of 93%, 89%, 100%, and 89%, respectively. The application of the standardized system to study the biodegradation of phenanthrene in an agricultural soil with and without inoculation of the high molecular weight PAH-degrading strain Mycobacterium sp. AP1, demonstrates its suitability for determining the environmental fate of PAHs in polluted soils and for evaluating the effect of bioremediative treatments. In inoculated microcosms 35% of the added phenanthrene was depleted, 19% being recovered as CO(2) and 3% as diphenic acid. The latter, together with other two unidentified metabolites, accumulated in soil.

  19. 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

  20. 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.

  1. Microcosm experiments to study the interaction of solid and solute phases during initial soil development

    NASA Astrophysics Data System (ADS)

    Zimmermann, C.; Chabbi, S.; Schaaf, W.

    2009-04-01

    During the initial phase of soil formation mineral weathering, interactions between the solid and liquid phases as well as accumulation of organic matter play an important role for the development of soil properties and for the establishment of vegetation and the colonization of soil biota. Our study is part of the Transregional Collaborative Research Centre (SFB/TRR 38) ‘Patterns and processes of initial ecosystem development in an artificial catchment' funded by the Deutsche Forschungsgemeinschaft (DFG). The catchment ´Chicken Creeḱ close to Cottbus (Germany) has a size of 6 ha and is composed of a 3-4 m layer of Quaternary loamy to sandy sediments overlying a 1-2 m clay layer. To connect interactions between the soil solid phase and soil solution at the micro-scale with observed processes at the catchment scale we perform microcosm experiments with soil samples from the catchment under controlled laboratory conditions. The microcosm experiments are carried out in a climate chamber at constant 10 °C corresponding to the mean annual temperature of the region. In total 48 soil columns with a diameter of 14.4 cm and height of 30 cm were filled with substrates of two textural compositions reflecting the gradients observed at the catchment and a bulk density of 1.4-1.5 g*cm3. Within the microcosms it is possible to control the gaseous phase and the water fluxes by artificial irrigation. The irrigation runs automated and quasi-continuously four times a day with 6.6 ml each (in total 600 mm*yr-1). Irrigation amount and chemical composition of the artificial rainwater are based on the annual mean at the field site. Litter of two different plant species occurring at the catchment site (Lotus corniculatus, Calamagrostis epigejos) labelled with stable isotopes (δ13C; δ15N) is used for the experiments. All treatments including a control run with four replicates. The gaseous phase in the headspace of the microcosms is analysed continuously for CO2 and N2O contents

  2. 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.

  3. 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.

  4. 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

  5. Competition between n-alkane-assimilating yeasts and bacteria during colonization of sandy soil microcosms.

    PubMed

    Schmitz, C; Goebel, I; Wagner, S; Vomberg, A; Klinner, U

    2000-07-01

    An n-alkane-assimilating strain of Candida tropicalis was selected in sandy soil inoculated with microorganisms from contaminated sites. Competition experiments with n-alkane utilizers from different strain collections confirmed that yeasts overgrow bacteria in sandy soil. Acidification of the soil is one of the colonization factors useful for the yeasts. It can be counteracted by addition of bentonite, a clay mineral with high ion exchange capacity, but not, however, by kaolin. Strains of different yeast species showed different levels of competitiveness. Strains of Arxula adeninivorans, Candida maltosa, and Yarrowia lipolytica overgrew strains of C. tropicalis, C. shehatae or Pichia stipitis. Two strains of C. maltosa and Y. lipolytica coexisted during several serial transfers under microcosm conditions.

  6. 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.

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

    PubMed

    Sheng, Haijun; Shen, Qirong; Feng, Ke

    2004-01-01

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

  8. Manure biochar influence upon soil properties, phosphorus distribution and phosphatase activities: A microcosm incubation study.

    PubMed

    Jin, Yi; Liang, Xinqiang; He, Miaomiao; Liu, Yu; Tian, Guangming; Shi, Jiyan

    2016-01-01

    Using manure-derived-biochar as an alternative phosphorus (P) source has bright future prospects to improve soil P status. A 98-day microcosm incubation experiment was set up for two soils which were amended with manure biochar at proportions of 0, 0.5% and 1.5%. Swine manure samples were air-dried and manure biochar was prepared by pyrolysis at 400 °C for 4 h. As determined by P-31 nuclear magnetic resonance ((31)P NMR) spectroscopy, manure biochar mainly increased the contents and fractions of orthophosphate and pyrophosphate in two soils, while decreased those of monoesters (P<0.05). At the end of incubation, 1.5% of manure biochar raised soil pH by 0.5 and 0.6 units, cation exchange capacity by 16.9% and 32.2%, and soil total P by 82.1% and 81.1% for silt loam and clay loam soils, respectively, as compared with those soils without biochar. Simultaneously, 1.5% of manure biochar decreased acid phosphomonoesterase activities by 18.6% and 34.0% for clay loam and silt loam, respectively; while it increased alkaline phosphomonoesterase activities by 28.5% and 95.1% for clay loam and silt loam, respectively. The enhancement of soil P availability after manure biochar addition was firstly due to the orthophosphate and pyrophosphate as the major P species in manure biochar which directly increased contents of soil inorganic P, and also attributed to the decomposition of some organic P like monoesters by enhanced alkaline phosphomonoesterase activities from manure biochar addition.

  9. 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

  10. Impact of acetochlor on ammonia-oxidizing bacteria in microcosm soils.

    PubMed

    Li, Xinyu; Zhang, Huiwen; Wu, Minna; Su, Zhencheng; Zhang, Chenggang

    2008-01-01

    Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised DGGE bands. DGGE profiles showed that acetochlor had a stimulating effect on AOB at the early stage after acetochlor amended, and the order of intensity and duration is medium-acetochlor amended samples (AM) > low-acetochlor amended samples (AL) > high-acetochlor amended samples (AH). At the end of 60 d microcosm, acetochlor had a negative effect on the diversity of AOB. Cluster analysis of DGGE profiles showed that acetochlor had a greater effect on the community structure of AOB on day 60 than on day 1. The phylogenetic analysis revealed that all the sequences of excised DGGE bands were closely related to members of the genus Nitrosospira and formed two separate subclusters designated as subcluster 1 and subcluster 2 affiliated respectively with clusters 3 and 4 in Nitrosospira as defined by Stephen. Some dominant AOB had a change from subcluster 2 to subcluster 1 with the incubation. The results showed that acetochlor had an effect on the AOB on a long-term basis and the chronic effect of acetochlor should be paid more attention in future.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Controlled Environment Soil-Core Microcosm Unit (CESMU) for Investigating Fate, Transport, and Transformation of Chemicals in Site-Specific Soils

    DTIC Science & Technology

    1994-06-01

    34 Acid Rain," Environment Vol. 14, pp 33-44 (1972). 12. The Soil Core Microcosm - A Potential Screening Tool, EPA-600/3-79-089, U.S. Environmental...AD-A284 768 EDGEWOOD U A CN DEMW APUENT & •ENGCWR Dh Ct ZER U.& ARMY CXZWCAL AND WOLOGICAL DErzNu COwLAND ERDEC-TR-088 CONTROLLED ENVIRONMENT SOIL ...CORE MICROCOSM UNIT (CESMU) FOR INVESTIGATING FATE, TRANSPORT, AND TRANSFORMATION OF CHEMICALS IN SITE-SPECIFIC SOILS Ronald T. Checkal Randall S

  17. Optimization of Differential Display of Prokaryotic mRNA: Application to Pure Culture and Soil Microcosms

    PubMed Central

    Fleming, James T.; Yao, Wen-Hsiang; Sayler, Gary S.

    1998-01-01

    The differential display (DD) technique, which is widely used almost exclusively for eukaryotic gene discovery, was optimized to detect differential mRNA transcription from both pure-culture and soil-derived bacterial RNA. A model system which included toluene induction of todC1 in Pseudomonas putida F1 was used to optimize the procedure. At 24-h tod induction was determined to be approximately 8 × 107 transcripts/μg or 0.08% of the total mRNA. The primer concentration, primer length, annealing temperature, and template, deoxynucleoside triphosphate, and MgCl2 concentrations were varied to optimize amplification of a todC1 fragment. The limit of detection of todC1 by DD was found to be 0.015 ng of total RNA template or approximately 103 transcripts. Once optimized, a todC1C2 gene fragment from P. putida F1 RNA was detected by using an arbitrary primer for the reverse transcriptase step in conjunction with the same arbitrary primer and a Shine-Dalgarno primer in the PCR. To verify the results, an arbitrary primer was used to detect recovery of a new salicylate-inducible naphthalene dioxygenase in Burkholderia cepacia JS150. The method was then used to detect mRNA induction in both inoculated and uninoculated toluene-induced soil microcosms. Several putative differentially expressed partial gene sequences obtained from the uninoculated microcosms were examined, and one novel fragment was found to be differentially expressed. PMID:9758787

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. Biogeochemical modeling of CO2 and CH4 production in anoxic Arctic soil microcosms

    NASA Astrophysics Data System (ADS)

    Tang, Guoping; Zheng, Jianqiu; Xu, Xiaofeng; Yang, Ziming; Graham, David E.; Gu, Baohua; Painter, Scott L.; Thornton, Peter E.

    2016-09-01

    Soil organic carbon turnover to CO2 and CH4 is sensitive to soil redox potential and pH conditions. However, land surface models do not consider redox and pH in the aqueous phase explicitly, thereby limiting their use for making predictions in anoxic environments. Using recent data from incubations of Arctic soils, we extend the Community Land Model with coupled carbon and nitrogen (CLM-CN) decomposition cascade to include simple organic substrate turnover, fermentation, Fe(III) reduction, and methanogenesis reactions, and assess the efficacy of various temperature and pH response functions. Incorporating the Windermere Humic Aqueous Model (WHAM) enables us to approximately describe the observed pH evolution without additional parameterization. Although Fe(III) reduction is normally assumed to compete with methanogenesis, the model predicts that Fe(III) reduction raises the pH from acidic to neutral, thereby reducing environmental stress to methanogens and accelerating methane production when substrates are not limiting. The equilibrium speciation predicts a substantial increase in CO2 solubility as pH increases, and taking into account CO2 adsorption to surface sites of metal oxides further decreases the predicted headspace gas-phase fraction at low pH. Without adequate representation of these speciation reactions, as well as the impacts of pH, temperature, and pressure, the CO2 production from closed microcosms can be substantially underestimated based on headspace CO2 measurements only. Our results demonstrate the efficacy of geochemical models for simulating soil biogeochemistry and provide predictive understanding and mechanistic representations that can be incorporated into land surface models to improve climate predictions.

  4. Biogeochemical modeling of CO2 and CH4 production in anoxic Arctic soil microcosms

    DOE PAGES

    Tang, Guoping; Zheng, Jianqiu; Xu, Xiaofeng; ...

    2016-09-12

    Soil organic carbon turnover to CO2 and CH4 is sensitive to soil redox potential and pH conditions. However, land surface models do not consider redox and pH in the aqueous phase explicitly, thereby limiting their use for making predictions in anoxic environments. Using recent data from incubations of Arctic soils, we extend the Community Land Model with coupled carbon and nitrogen (CLM-CN) decomposition cascade to include simple organic substrate turnover, fermentation, Fe(III) reduction, and methanogenesis reactions, and assess the efficacy of various temperature and pH response functions. Incorporating the Windermere Humic Aqueous Model (WHAM) enables us to approximately describe themore » observed pH evolution without additional parameterization. Although Fe(III) reduction is normally assumed to compete with methanogenesis, the model predicts that Fe(III) reduction raises the pH from acidic to neutral, thereby reducing environmental stress to methanogens and accelerating methane production when substrates are not limiting. The equilibrium speciation predicts a substantial increase in CO2 solubility as pH increases, and taking into account CO2 adsorption to surface sites of metal oxides further decreases the predicted headspace gas-phase fraction at low pH. Without adequate representation of these speciation reactions, as well as the impacts of pH, temperature, and pressure, the CO2 production from closed microcosms can be substantially underestimated based on headspace CO2 measurements only. Our results demonstrate the efficacy of geochemical models for simulating soil biogeochemistry and provide predictive understanding and mechanistic representations that can be incorporated into land surface models to improve climate predictions.« less

  5. Crude oil degradation efficiency of a recombinant Acinetobacter baumannii strain and its survival in crude oil-contaminated soil microcosm.

    PubMed

    Mishra, Sanjeet; Sarma, Priyangshu M; Lal, Banwari

    2004-06-15

    A hydrocarbon degrading Acinetobacter baumannii S30 strain, isolated from crude oil-contaminated soil, was inserted with the lux gene from the luciferase gene cassette luxCDABE. Soil microcosms were designed to study the degradation efficacy for total petroleum hydrocarbon (TPH) of crude oil by lux-tagged A. baumannii S30 pJES. Bioaugmentation of a TPH-contaminated microcosm with A baumannii S30 pJES showed that TPH levels were reduced from 89.3 to 53.9 g/kg soil in 90 days. Biodegradation of TPH by A baumannii S30 pJES was also monitored in shake flask conditions, which showed a reduction of initial TPH levels by over 50% at the end of 120 h. A lux-PCR-based approach along with the standard dilution plating with selective antibiotics was successfully utilized to monitor the survivability of the lux-tagged strain A. baumannii S30 pJES in soil microcosms and stability of the lux insert in the host strain A. baumannii S30. The selective plating technique indicated the population of A. baumannii S30 pJES to be 6.5+/-0.13 x 10(8) CFU/g at day zero (just after bioaugmentation) and 2.09+/-0.08 x 10(8) CFU/g of soil after 90 days of incubation. lux-PCR confirmed the stability of the insert in all the randomly selected colonies of A. baumannii strains from the antibiotic plates. The lux insert was stable after 50 generations in Luria Bertini broth and storage at -70 degrees C as glycerol stocks for over a year. These results revealed that the lux insert was stable and lux-tagged A. baumannii S30 strain could survive in a TPH-contaminated soil microcosm and could degrade TPH in the soil microcosm conditions. It can be used as an effective marker to monitor the survival of augmented strains at a bioremediation site.

  6. Soil microbial diversity and soil functioning affect competition among grasses in experimental microcosms.

    PubMed

    Bonkowski, Michael; Roy, Jacques

    2005-03-01

    A gradient of microbial diversity in soil was established by inoculating pasteurized soil with microbial populations of different complexity, which were obtained by a combination of soil fumigation and filtering techniques. Four different soil diversity treatments were planted with six different grass species either in monoculture or in polyculture to test how changes of general microbial functions, such as catabolic diversity and nutrient recycling efficiency would affect the performance of the plant communities. Relatively harsh soil treatments were necessary to elicit visible effects on major soil processes such as decomposition and nitrogen cycling due to the high redundancy and resilience of soil microbial communities. The strongest effects of soil diversity manipulations on plant growth occurred in polycultures where interspecific competition between plants was high. In polycultures, soil diversity reduction led to a gradual, linear decline in biomass production of one subordinate grass species (Bromus hordeaceus), which was compensated by increased growth of two intermediate competitors (Aegilops geniculata, B. madritensis). This negative covariance in growth of competing grass species smoothed the effects of soil diversity manipulations at the plant community level. As a result, total shoot biomass production remained constant. Apparently the effects of soil diversity manipulations were buffered because functional redundancy at both, the microbial and the plant community level complemented each other. The results further suggests that small trade-offs in plant fitness due to general functional shifts at the microbial level can be significant for the outcome of competition in plant communities and thus diversity at much larger scales.

  7. Decomposition of leaves of the metallophyte Arabidopsis halleri in soil microcosms: fate of Zn and Cd from plant residues.

    PubMed

    Boucher, Uriel; Lamy, Isabelle; Cambier, Philippe; Balabane, May

    2005-05-01

    In order to better understand the fate of metals during the biodegradation of organic matter in soils, an in vitro incubation experiment was conducted with metal-rich and metal-free leaves of Arabidopsis halleri introduced in a non-contaminated soil. During incubation of these microcosms, we followed the partitioning of Zn and Cd between the solution and their solid components, by determining the metal contents of six soil fractions and dissolved metals after granulo-densimetric separations at selected times. Microbial biomass and exchangeable metals in K(2)SO(4) solutions were also determined at the same times, and two main stages were identified. The first one takes place after a fast abiotic transfer of Zn and Cd from readily soluble plant tissues onto fine soil constituents, keeping metals away from the liquid phase: during about 14 days, microbial biomass increased as well as metal contents of some soil fractions, particularly those rich in particulate organic matter. During the second stage, between 14 and 60 days and for the metal-rich microcosms, Zn and Cd contents in solution increased, while microbial biomass decreased instead of staying constant as in control. A change of Zn and Cd speciation is assumed, from non-toxic adsorbed forms to more toxic species in solution. Remaining metal-rich plant residues seem to create a stable organic C compartment in the soil.

  8. 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.

  9. 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.

  10. Effects of fumigants on microbial diversity and persistence of E. coli O15:H7 in contrasting soil microcosms.

    PubMed

    Ibekwe, A Mark; Ma, J

    2011-09-01

    Persistence of E. coli O157 in the environment is a serious public health concern. However, little is known about the persistence of this pathogen after exposure to chemical compounds like fumigants in the environment. In this study, the persistence behavior of pathogenic E. coli O157:H7 was investigated after fumigation with methyl bromide (MeBr; CH(3)Br) and methyl iodide (MeI, iodomethane; CH(3)I) in soil microcosms under laboratory conditions. Our goal was to assess changes in soil microbial community structure and persistence of E. coli O157:H7 in microcosm soils after fumigation. PCR was used to amplify 16S rRNA genes from total bacterial community composition, and the products were subjected to denaturing gradient gel electrophoresis (DGGE). Microbial diversity as determined by DGGE was significantly higher in clay soil than sandy soil. Real-time PCR and plate counts were used to quantify the survival of E. coli O157:H7 in the two soils after fumigation with MeBr and MeI. The survival of the pathogen was higher in the non fumigated controls than the fumigated treatments when determined using plate counts. These results were confirmed by real time PCR analysis targeting the stx1, stx2, and the eae genes. E. coli O157:H7 survived for about 35 days when determined using the plate count method but continued to be detected at about the detection limit of 10(2) by real time PCR for more than 86 days. Our results showed that there was a fast inactivation of the pathogen during the first 35 days. After this period, a small proportion of the pathogen continued to survive in the soil microcosms. Subsequent enrichment of soil samples and immunomagnetic separation revealed the continuous presence of viable cells after 86 days of incubation. The data presented contribute to a better understanding of the behavior of E. coli O157:H7 in soil, and showed the need for more investigation of the role of dormant cells in soil that may be a source for recontamination of the

  11. 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.

  12. 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.

  13. 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

  14. Disturbance Promotes Non-Indigenous Bacterial Invasion in Soil Microcosms: Analysis of the Roles of Resource Availability and Community Structure

    PubMed Central

    Liu, Manqiang; Bjørnlund, Lisa; Rønn, Regin; Christensen, Søren; Ekelund, Flemming

    2012-01-01

    Background Invasion-biology is largely based on non-experimental observation of larger organisms. Here, we apply an experimental approach to the subject. By using microbial-based microcosm-experiments, invasion-biology can be placed on firmer experimental, and hence, less anecdotal ground. A better understanding of the mechanisms that govern invasion-success of bacteria in soil communities will provide knowledge on the factors that hinder successful establishment of bacteria artificially inoculated into soil, e.g. for remediation purposes. Further, it will yield valuable information on general principles of invasion biology in other domains of life. Methodology/Principal Findings Here, we studied invasion and establishment success of GFP-tagged Pseudomonas fluorescens DSM 50090 in laboratory microcosms during a 42-day period. We used soil heating to create a disturbance gradient, and hypothesized that increased disturbance would facilitate invasion; our experiments confirmed this hypothesis. We suggest that the key factors associated with the heating disturbance that explain the enhanced invasion success are increased carbon substrate availability and reduced diversity, and thus, competition- and predation-release. In a second experiment we therefore separated the effects of increased carbon availability and decreased diversity. Here, we demonstrated that the effect of the indigenous soil community on bacterial invasion was stronger than that of resource availability. In particular, introduced bacteria established better in a long term perspective at lower diversity and predation pressure. Conclusion We propose increased use of microbial systems, for experimental study of invasion scenarios. They offer a simple and cost-efficient way to study and understand biological invasion. Consequently such systems can help us to better predict the mechanisms controlling changes in stability of communities and ecosystems. This is becoming increasingly relevant since

  15. 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.

  16. Use of potassium tellurite for testing the survival and viability of Pseudomonas pseudoalcaligenes KF707 in soil microcosms contaminated with polychlorinated biphenyls.

    PubMed

    Zanaroli, Giulio; Fedi, Stefano; Carnevali, Monica; Fava, Fabio; Zannoni, Davide

    2002-01-01

    This study shows that the oxyanion tellurite TeO3(2-) can be used as a tool to detect and quantify the release in soil microcosms of Pseudomonas pseudoalcaligenes KF707, a strain spontaneously resistant to tellurite with a minimal inhibitory concentration (MIC) of 150 microg ml(-1). KF707 cells which carry the genes for degradation of a wide range of polychlorinated biphenyl congeners (PCBs) were used for inoculation of laboratory microcosms prepared with two different PCB-contaminated soils (Ci/s and Di/s) in the presence or absence of biphenyl as carbon source. In all microcosms supplemented with biphenyl, significant survival of strain KF707 was noted over a time period of 35 days; conversely, in microcosms containing Ci/s soil without biphenyl addition a rapid decrease in KF707 inoculated cells was observed. By comparing the number of inoculated KF707 cells with the number of indigenous bacteria growing on biphenyl (IBGB) of both Ci/s and Di/s microcosms, it could be concluded that the KF707/IBGB ratio is a relevant parameter in determining the fate of the added strain. The efficacy of potassium tellurite as a selective marker to monitor strain KF707 in laboratory microcosms was confirmed by ARDRA analyses of the 16S rDNA, while the isolated indigenous bacteria growing on biphenyl were identified as members of three different species of the genus Pseudomonas. We also report that in microcosms inoculated with KF707 cells in the absence of biphenyl, only low chlorinated biphenyls were degraded.

  17. Aerobic biomineralization of alpha-hexachlorocyclohexane in contaminated soil

    SciTech Connect

    Bachmann, A.; de Bruin, W.; Jumelet, J.C.; Rijnaarts, H.H.; Zehnder, A.J.

    1988-02-01

    The factors identified to be important for the aerobic biodegradation of alpha-hexachlorocyclohexane (alpha-HCH) in a soil slurry are temperature, auxiliary carbon source, substrate concentration, and soil inhomogeneities. Temperatures in the range of 20 to 30/sup 0/C were determined to be most favorable for biodegradation of alpha-HCH. No alpha-HCH biodegradation was detected at temperatures below 4/sup 0/C and above 40/sup 0/C. The addition of auxiliary organic carbon compounds showed repressive effects on alpha-HCH biomineralization. Increased oxygen partial pressures reduced the repressive effects of added auxiliary organic carbon compounds. A linear relationship between alpha-HCH concentration and its conversion rate was found in a Lineweaver-Burk plot. Inhomogeneities such as clumping of alpha-HCH significantly affected its biodegradation. Inhomogeneity as an influence on biodegradation has not drawn sufficient attention in the past, even though it certainly has affected both laboratory studies and the application of biotechnological methods to clean up contaminated sites. On the basis of metabolites detected during degradation experiments, the initial steps of aerobic alpha-HCH bioconversion in a soil slurry are proposed.

  18. Decomposition in soil microcosms of leaves of the metallophyte Arabidopsis halleri: effect of leaf-associated heavy metals on biodegradation.

    PubMed

    Boucher, Uriel; Balabane, May; Lamy, Isabelle; Cambier, Philippe

    2005-05-01

    More knowledge is needed concerning the disturbance of soil organic matter cycling due to heavy metal pollution. The present study deals with the impact of heavy metal pollution on litter breakdown. Our aim was to assess whether heavy metals initially present in the leaves of the metallophyte Arabidopsis halleri: (i) slow down the rate of C mineralization, in relation to metal toxicity towards microflora, and/or (ii) increase the amount of organic C resistant to biodegradation, in relation to an intrinsic resistance of metallophyte residues to biodegradation. We incubated uncontaminated soil samples with either metal-free or metal-rich plant material. Metal-free material was grown in a greenhouse, and metal-rich material was collected in situ. During the 2-month period of incubation, we measured evolved CO(2)-C and residual plant C in the coarse organic fraction. Our results of CO(2)-C evolution showed a similar mineralization from the microcosms amended with highly metal-rich leaves of A. halleri and the microcosms amended with the metal-free but otherwise similar plant material. Measuring residual plant C in its input size-fraction gave a more precise insight. Our results suggest that only the large pool of easily decomposable C mineralized similarly from metal-free and from metal-rich plant residues. The pool of less decomposable C seemed on the contrary to be preferentially preserved in the case of metal-rich material. These results support the hypothesis of an annual extra-accumulation in situ of such a slowly decomposable fraction of plant residues which could account to some extent for the observed accumulation of metallophyte litter on the surface of highly metal-polluted soils.

  19. 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.

  20. Consortia of low-abundance bacteria drive sulfate reduction-dependent degradation of fermentation products in peat soil microcosms.

    PubMed

    Hausmann, Bela; Knorr, Klaus-Holger; Schreck, Katharina; Tringe, Susannah G; Glavina Del Rio, Tijana; Loy, Alexander; Pester, Michael

    2016-10-01

    Dissimilatory sulfate reduction in peatlands is sustained by a cryptic sulfur cycle and effectively competes with methanogenic degradation pathways. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16-174 nmol cm(-3) per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (⩾0.1% estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of recognized sulfate-reducing taxa (Desulfosporosinus, Desulfopila, Desulfomonile, Desulfovibrio) and also members of taxa that are either yet unknown sulfate reducers or metabolic interaction partners thereof. Most responsive OTUs markedly increased their ribosome content but only weakly increased in abundance. Responsive Desulfosporosinus OTUs even maintained a constantly low population size throughout 50 days, which suggests a novel strategy of rare biosphere members to display activity. Interestingly, two OTUs of the non-sulfate-reducing genus Telmatospirillum (Alphaproteobacteria) showed strongly contrasting preferences towards sulfate in butyrate-amended microcosms, corroborating that closely related microorganisms are not necessarily ecologically coherent. We show that diverse consortia of low-abundance microorganisms can perform peat soil sulfate reduction, a process that exerts control on methane production in these climate-relevant ecosystems.

  1. Consortia of low-abundance bacteria drive sulfate reduction-dependent degradation of fermentation products in peat soil microcosms

    SciTech Connect

    Hausmann, Bela; Knorr, Klaus-Holger; Schreck, Katharina; Tringe, Susannah G.; Glavina del Rio, Tijana; Loy, Alexander; Pester, Michael

    2016-03-25

    A cryptic sulfur cycle and effectively competes with methanogenic degradation pathways sustains dissimilatory sulfate reduction in peatlands. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16–174 nmol cm–3 per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (greater than or equal to0.1% estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of recognized sulfate-reducing taxa (Desulfosporosinus, Desulfopila, Desulfomonile, Desulfovibrio) and also members of taxa that are either yet unknown sulfate reducers or metabolic interaction partners thereof. The most responsive OTUs markedly increased their ribosome content but only weakly increased in abundance. Responsive Desulfosporosinus OTUs even maintained a constantly low population size throughout 50 days, which suggests a novel strategy of rare biosphere members to display activity. Interestingly, two OTUs of the non-sulfate-reducing genus Telmatospirillum (Alphaproteobacteria) showed strongly contrasting preferences towards sulfate in butyrate-amended microcosms, corroborating that closely related microorganisms are not necessarily ecologically coherent. We show that diverse consortia of low-abundance microorganisms can perform peat soil sulfate reduction, a process that exerts control on methane production in these climate-relevant ecosystems.

  2. Consortia of low-abundance bacteria drive sulfate reduction-dependent degradation of fermentation products in peat soil microcosms

    DOE PAGES

    Hausmann, Bela; Knorr, Klaus-Holger; Schreck, Katharina; ...

    2016-03-25

    A cryptic sulfur cycle and effectively competes with methanogenic degradation pathways sustains dissimilatory sulfate reduction in peatlands. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16–174 nmol cm–3 per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (greater than or equal to0.1%more » estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of recognized sulfate-reducing taxa (Desulfosporosinus, Desulfopila, Desulfomonile, Desulfovibrio) and also members of taxa that are either yet unknown sulfate reducers or metabolic interaction partners thereof. The most responsive OTUs markedly increased their ribosome content but only weakly increased in abundance. Responsive Desulfosporosinus OTUs even maintained a constantly low population size throughout 50 days, which suggests a novel strategy of rare biosphere members to display activity. Interestingly, two OTUs of the non-sulfate-reducing genus Telmatospirillum (Alphaproteobacteria) showed strongly contrasting preferences towards sulfate in butyrate-amended microcosms, corroborating that closely related microorganisms are not necessarily ecologically coherent. We show that diverse consortia of low-abundance microorganisms can perform peat soil sulfate reduction, a process that exerts control on methane production in these climate-relevant ecosystems.« less

  3. Consortia of low-abundance bacteria drive sulfate reduction-dependent degradation of fermentation products in peat soil microcosms

    PubMed Central

    Hausmann, Bela; Knorr, Klaus-Holger; Schreck, Katharina; Tringe, Susannah G; Glavina del Rio, Tijana; Loy, Alexander; Pester, Michael

    2016-01-01

    Dissimilatory sulfate reduction in peatlands is sustained by a cryptic sulfur cycle and effectively competes with methanogenic degradation pathways. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16–174 nmol cm–3 per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (⩾0.1% estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of recognized sulfate-reducing taxa (Desulfosporosinus, Desulfopila, Desulfomonile, Desulfovibrio) and also members of taxa that are either yet unknown sulfate reducers or metabolic interaction partners thereof. Most responsive OTUs markedly increased their ribosome content but only weakly increased in abundance. Responsive Desulfosporosinus OTUs even maintained a constantly low population size throughout 50 days, which suggests a novel strategy of rare biosphere members to display activity. Interestingly, two OTUs of the non-sulfate-reducing genus Telmatospirillum (Alphaproteobacteria) showed strongly contrasting preferences towards sulfate in butyrate-amended microcosms, corroborating that closely related microorganisms are not necessarily ecologically coherent. We show that diverse consortia of low-abundance microorganisms can perform peat soil sulfate reduction, a process that exerts control on methane production in these climate-relevant ecosystems. PMID:27015005

  4. Aerobic biodegradation of propylene glycol by soil bacteria.

    PubMed

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

    2013-09-01

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

  5. Culturable Populations of Sporomusa spp. and Desulfovibrio spp. in the Anoxic Bulk Soil of Flooded Rice Microcosms

    PubMed Central

    Rosencrantz, Dirk; Rainey, Frederick A.; Janssen, Peter H.

    1999-01-01

    Most-probable-number (MPN) counts were made of homoacetogenic and other bacteria present in the anoxic flooded bulk soil of laboratory microcosms containing 90- to 95-day-old rice plants. MPN counts with substrates known to be useful for the selective enrichment or the cultivation of homoacetogenic bacteria (betaine, ethylene glycol, 2,3-butanediol, and 3,4,5-trimethoxybenzoate) gave counts of 2.3 × 103 to 2.8 × 105 cells per g of dry soil. Homoacetogens isolated from the terminal positive steps of these dilution cultures belonged to the genus Sporomusa. Counts with succinate, ethanol, and lactate gave much higher MPNs of 5.9 × 105 to 3.4 × 107 cells per g of dry soil and led to the isolation of Desulfovibrio spp. Counting experiments on lactate and ethanol which included Methanospirillum hungatei in the medium gave MPNs of 2.3 × 106 to 7.5 × 108 cells per g of dry soil and led to the isolation of Sporomusa spp. The latter strains could grow with betaine, ethylene glycol, 2,3-butanediol, and/or 3,4,5-trimethoxybenzoate, but apparently most cells of Sporomusa spp. did not initiate growth in counting experiments with those substrates. Spores apparently accounted for 2.2% or less of the culturable bacteria. It appears that culturable Desulfovibrio spp. and Sporomusa spp. were present in approximately equal numbers in the bulk soil. Multiple, phylogenetically-distinct, phenotypically-different, strains of each genus were found in the same soil system. PMID:10427044

  6. 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.

  7. Citrate and malonate increase microbial activity and alter microbial community composition in uncontaminated and diesel-contaminated soil microcosms

    NASA Astrophysics Data System (ADS)

    Martin, Belinda C.; George, Suman J.; Price, Charles A.; Shahsavari, Esmaeil; Ball, Andrew S.; Tibbett, Mark; Ryan, Megan H.

    2016-09-01

    Petroleum hydrocarbons (PHCs) are among the most prevalent sources of environmental contamination. It has been hypothesized that plant root exudation of low molecular weight organic acid anions (carboxylates) may aid degradation of PHCs by stimulating heterotrophic microbial activity. To test their potential implication for bioremediation, we applied two commonly exuded carboxylates (citrate and malonate) to uncontaminated and diesel-contaminated microcosms (10 000 mg kg-1; aged 40 days) and determined their impact on the microbial community and PHC degradation. Every 48 h for 18 days, soil received 5 µmol g-1 of (i) citrate, (ii) malonate, (iii) citrate + malonate or (iv) water. Microbial activity was measured daily as the flux of CO2. After 18 days, changes in the microbial community were assessed by a community-level physiological profile (CLPP) and 16S rRNA bacterial community profiles determined by denaturing gradient gel electrophoresis (DGGE). Saturated PHCs remaining in the soil were assessed by gas chromatography-mass spectrometry (GC-MS). Cumulative soil respiration increased 4- to 6-fold with the addition of carboxylates, while diesel contamination resulted in a small, but similar, increase across all carboxylate treatments. The addition of carboxylates resulted in distinct changes to the microbial community in both contaminated and uncontaminated soils but only a small increase in the biodegradation of saturated PHCs as measured by the n-C17 : pristane biomarker. We conclude that while the addition of citrate and malonate had little direct effect on the biodegradation of saturated hydrocarbons present in diesel, their effect on the microbial community leads us to suggest further studies using a variety of soils and organic acids, and linked to in situ studies of plants, to investigate the role of carboxylates in microbial community dynamics.

  8. 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

  9. 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

    2015-12-18

    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.

  10. 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

  11. Natural Electrotransformation of Lightning-Competent Pseudomonas sp. Strain N3 in Artificial Soil Microcosms

    PubMed Central

    Cérémonie, Hélène; Buret, François; Simonet, Pascal; Vogel, Timothy M.

    2006-01-01

    The lightning-competent Pseudomonas sp. strain N3, recently isolated from soil, has been used to study the extent of natural electrotransformation (NET) or lightning transformation as a horizontal gene transfer mechanism in soil. The variation of electrical fields applied to the soil with a laboratory-scale lightning system provides an estimate of the volume of soil affected by NET. Based on the range of the electric field that induces NET of Pseudomonas strain N3, the volume of soil, where NET could occur, ranges from 2 to 950 m3 per lightning strike. The influence of DNA parameters (amount, size, and purity) and DNA soil residence time were also investigated. NET frequencies (electrotransformants/recipient cells) ranged from 10−8 for cell lysate after 1 day of residence in soil to 4 × 10−7 with a purified plasmid added immediately before the lightning. The electrical field gradient (in kilovolts per cm) also played a role as NET frequencies ranging from 1 × 10−5 at 2.3 kV/cm to 1.7 × 10−4 at 6.5 kV/cm. PMID:16597934

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. Inoculation of PAH-degrading strains of Fusarium solani and Arthrobacter oxydans in rhizospheric sand and soil microcosms: microbial interactions and PAH dissipation.

    PubMed

    Thion, Cécile; Cébron, Aurélie; Beguiristain, Thierry; Leyval, Corinne

    2013-07-01

    Very little is known about the influence of bacterial-fungal ecological interactions on polycyclic aromatic hydrocarbon (PAH) dissipation in soils. Fusarium solani MM1 and Arthrobacter oxydans MsHM11 can dissipate PAHs in vitro. We investigated their interactions and their effect on the dissipation of three PAHs-phenanthrene (PHE), pyrene (PYR) and dibenz(a,h)anthracene (DBA)-in planted microcosms, in sterile sand or non-sterile soil. In sterile sand microcosms planted with alfalfa, the two microbes survived and grew, without any significant effect of co-inoculation. Co-inoculation led to the dissipation of 46 % of PHE after 21 days. In soil microcosms, whether planted with alfalfa or not, both strains persisted throughout the 46 days of the experiment, without any effect of co-inoculation or of alfalfa, as assessed by real-time PCR targeting taxon-level indicators, i.e. Actinobacteria 16S rDNA and the intergenic transcribed spacer specific to the genus Fusarium. The microbial community was analyzed by temporal temperature gradient electrophoresis and real-time PCR targeting bacterial and fungal rDNA and PAH-ring hydroxylating dioxygenase genes. These communities were modified by PAH pollution, which selected PAH-degrading bacteria, by the presence of alfalfa and, concerning the bacterial community, by inoculation. PHE and PYR concentrations significantly decreased (91 and 46 %, respectively) whatever the treatment, but DBA concentration significantly decreased (30 %) in planted and co-inoculated microcosms only.

  18. Interactions of bacterial and amoebal populations in soil microcosms with fluctuating moisture content.

    PubMed

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

    1982-04-01

    Sterilized soil samples (20 g of soil per 50-ml flask), amended with 600 mug of glucose-carbon and 60 mug of NH(4)-N . g of dry soil, 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.

  19. A short-term study on the interaction of bacteria, fungi and endosulfan in soil microcosm.

    PubMed

    Xie, Huijun; Gao, Fuwei; Tan, Wei; Wang, Shu-Guang

    2011-12-15

    Endosulfan is one of the few organic chlorine insecticides still in use today in many developing countries. It has medium toxicity for fish and aquatic invertebrates. In this study, we added different concentrations of endosulfan to a series of soil samples collected from Baihua Park in Jinan, Shandong Province, China. Interactions of exogenous endosulfan, bacteria and fungi were analyzed by monitoring the changes in microbe-specific phospholipid fatty acids (PLFA), residual endosulfan and its metabolites which include; endosulfan sulfate, endosulfan lactone and endosulfan diol during a 9 days incubation period. Our results showed that endosulfan reduced fungi biomass by 47% on average after 9 days, while bacteria biomass increased 76% on average. In addition, we found that endosulfan degraded 8.62% in natural soil (NE), 5.51% in strepolin soil (SSE) and 2.47% in sterile soil (SE). Further analysis of the endosulfan metabolites in NE and SSE, revealed that the amount of endosulfan sulfate (ES) significantly increased and that of endosulfan lactone (EL) slightly decreased in both samples after 9 days. However, that of endosulfan diol (ED) increased in NE and decreased in SSE. After collective analysis our data demonstrated that fungi and bacteria responded differently to exogeous endosulfan, in a way that could promote the formation of endosulfan diol during endosulfan degradation.

  20. 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

  1. 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.

  2. Isolation and characterization of medically important aerobic actinomycetes in soil of iran (2006 - 2007).

    PubMed

    Aghamirian, Mohammad Reza; Ghiasian, Seyed Amir

    2009-01-01

    The aerobic actinomycetes are a large group of soil-inhabiting bacteria that occur worldwide. Some of them are the main cause of two important diseases, nocardiosis and actinomycetoma. To identify the prevalence and geographic distribution of aerobic actinomycetes in soil of Qazvin province, a study was carried out during 2006-2007. In this study, the incidence and diversity of medically important aerobic actinomycetes was determined in 300 soil samples of different parts of Qazvin. The suspensions of superficial soil samples were prepared by adding of normal saline, streptomycin and chloramphenicol and the supernatants were cultured on brain-heart infusion agar and Sabouraud's dextrose agar contain cycloheximide. The isolated microorganisms were examined by Gram and acid-fast stains and were identified biochemically and morphologically. Of 96 aerobic actinomycetes isolates identified, Actinomadura madurae and Streptomyces somaliensis were the most frequently isolated species each representing 19.8% of isolates, followed by Nocardia asteroides (15.6%), N. otitidiscaviarum (9.4%), N. brasiliensis (7.3%), A. peletieri, S. griseus, and Nocardia spp. (each 5.2%), and N. transvalensis, Nocardiopsis dassonvillei, Actinomadura spp. and Streptomyces spp. (each 3.1%). To the best of our knowledge, this is the first report on epidemiological investigation of medically important aerobic actinomycetes in soil samples from Iran. In recent years, mycetoma and nocardiosis have been increasingly reported in Iran. The results showed that medically important actinomycetes occur in the environment of Iran and soil could be potential source of actinomycotic infections.

  3. 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

  4. 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 ...

  5. 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.

  6. 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.

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

    PubMed Central

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

    1996-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Biodegradation of Guanidinium Ion in Aerobic Soil Samples

    DTIC Science & Technology

    1987-01-01

    Frederick. Maryland 21701 The manufacture of several munitions, polymeric resins , flame retardants, and pharmaceuticals utilizes guanidine salts as... Melamines and Guanidines. J Sci Soil Manure Jpn 15:569-574 Lees H, Quastel JH (1947) Biochemistry of Nitrification in Soil. III. Nitrification of Various

  13. Biodegradation of Cry1Ab protein from Bt transgenic rice in aerobic and flooded paddy soils.

    PubMed

    Wang, Haiyan; Ye, Qingfu; Gan, Jay; Wu, Licheng

    2007-03-07

    Degradation of Cry1Ab protein from Bt transgenic rice was examined under both aerobic and flooded conditions in five paddy soils and in aqueous solutions. The hydrolysis rate of Cry1Ab protein in aqueous solutions was correlated inversely with the solution pH in the range of 4.0 to 8.0, and positively with the initial concentration of Cry1Ab protein. Rapid degradation of Cry1Ab protein occurred in paddy soils under aerobic conditions, with half-lives ranging from 19.6 to 41.3 d. The degradation was mostly biotic and not related to any specific soil property. Degradation of the Cry1Ab protein was significantly prolonged under flooded conditions compared with aerobic conditions, with half-lives extended to 45.9 to 141 d. These results suggest that the toxin protein, when introduced into a paddy field upon harvest, will probably undergo rapid removal after the field is drained and exposed to aerobic conditions.

  14. Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.

    PubMed

    Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A; Mortuza, M Golam; Gadd, Geoffrey Michael

    2017-03-01

    Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se(0)) under both aerobic and anaerobic conditions. The biogenic nano-Se(0) converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg(0)) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg(0) remediation, probably owing to the release of intracellular nano-Se(0) from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se(0) and Hg(0). Biosynthesis of nano-Se(0) both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg(0)-contaminated surface and subsurface soils, where the redox potential often changes dramatically.

  15. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    PubMed

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

  16. 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…

  17. Links between sulphur oxidation and sulphur-oxidising bacteria abundance and diversity in soil microcosms based on soxB functional gene analysis.

    PubMed

    Tourna, Maria; Maclean, Paul; Condron, Leo; O'Callaghan, Maureen; Wakelin, Steven A

    2014-06-01

    Sulphur-oxidising bacteria (SOB) play a key role in the biogeochemical cycling of sulphur in soil ecosystems. However, the ecology of SOB is poorly understood, and there is little knowledge about the taxa capable of sulphur oxidation, their distribution, habitat preferences and ecophysiology. Furthermore, as yet there are no conclusive links between SOB community size or structure and rates of sulphur oxidation. We have developed a molecular approach based on primer design targeting the soxB functional gene of nonfilamentous chemolithotrophic SOB that allows assessment of both abundance and diversity. Cloning and sequencing revealed considerable diversity of known soxB genotypes from agricultural soils and also evidence for previously undescribed taxa. In a microcosm experiment, abundance of soxB genes increased with sulphur oxidation rate in soils amended with elemental sulphur. Addition of elemental sulphur to soil had a significant effect in the soxB gene diversity, with the chemolithotrophic Thiobacillus-like Betaproteobacteria sequences dominating clone libraries 6 days after sulphur application. Using culture-independent methodology, the study provides evidence for links between abundance and diversity of SOB and sulphur oxidation. The methodology provides a new tool for investigation of the ecology and role of SOB in soil sulphur biogeochemistry.

  18. Archaea produce lower yields of N2 O than bacteria during aerobic ammonia oxidation in soil.

    PubMed

    Hink, Linda; Nicol, Graeme W; Prosser, James I

    2016-03-11

    Nitrogen fertilisation of agricultural soil contributes significantly to emissions of the potent greenhouse gas nitrous oxide (N2 O), which is generated during denitrification and, in oxic soils, mainly by ammonia oxidisers. Although laboratory cultures of ammonia oxidising bacteria (AOB) and archaea (AOA) produce N2 O, their relative activities in soil are unknown. This work tested the hypothesis that AOB dominate ammonia oxidation and N2 O production under conditions of high inorganic ammonia (NH3 ) input, but result mainly from the activity of AOA when NH3 is derived from mineralisation. 1-octyne, a recently discovered inhibitor of AOB, was used to distinguish N2 O production resulting from archaeal and bacterial ammonia oxidation in soil microcosms, and specifically inhibited AOB growth, activity and N2 O production. In unamended soils, ammonia oxidation and N2 O production were lower and resulted mainly from ammonia oxidation by AOA. The AOA N2 O yield relative to nitrite produced was half that of AOB, likely due to additional enzymatic mechanisms in the latter, but ammonia oxidation and N2 O production were directly linked in all treatments. Relative contributions of AOA and AOB to N2 O production, therefore, reflect their respective contributions to ammonia oxidation. These results suggest potential mitigation strategies for N2 O emissions from fertilised agricultural soils.

  19. 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

  20. Two engineered approaches for treatment of explosives contaminated soils using both aerobic and anaerobic consortia

    SciTech Connect

    Harvey, S.D.; Fredrickson, H.; Hill, D.O.; Zappi, M.; Stryker, R.; Eng, S.; Harlow, J.

    1996-12-31

    The Naval Weapons Station Yorktown, Yorktown, Virginia (WPNSTA Yorktown) has contaminated soils from past handling, loading, and packing activities involving explosive compounds. Bench scale experiments were undertaken to examine the effectiveness of biological treatment. The experiments were conducted in two different reactor configurations: bioslurry (continuous mixing) and biocell (intermittent mixing). Treatments examined the effects of different cometabolites, bioaugmentation, surfactant enhanced desorption and both aerobic and anaerobic conditions.

  1. Biodegradation of clomazone in a California rice field soil: carbon allocation and community effects.

    PubMed

    Tomco, Patrick L; Holmes, William E; Tjeerdema, Ronald S

    2013-03-20

    Degradation pathways for the herbicide clomazone in a California rice field soil were characterized via pulse-labeling of anaerobic (flooded) and aerobic (moist) soil microcosms. Clomazone-derived (13)C in the major C pools of a rice ecosystem and soil phospholipid fatty acid (PLFA) profiles were analyzed over time to determine if (1) the compound accumulates in the microbial biomass, (2) it affects temporal microbial population dynamics, and (3) it is either preferentially metabolized or cometabolized. In anaerobic microcosms, the compound was rapidly biotransformed to ring-open clomazone, upon which it persisted in the aqueous phase, whereas aerobic microcosms degraded it slower but a greater percentage was mineralized. Anaerobic biomass decreased after clomazone was added, and aerobic actinomycete abundance differed between treatments and controls. Additionally, PLFA and (13)C PLFA were statistically similar between treatment and controls. Thus, microbial cometabolism is likely to be the dominant degrading mechanism governing clomazone fate in California rice fields.

  2. 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.

  3. 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

  4. Diversity and Structure of the Methanogenic Community in Anoxic Rice Paddy Soil Microcosms as Examined by Cultivation and Direct 16S rRNA Gene Sequence Retrieval

    PubMed Central

    Großkopf, Regine; Janssen, Peter H.; Liesack, Werner

    1998-01-01

    A dual approach consisting of cultivation and molecular retrieval of partial archaeal 16S rRNA genes was carried out to characterize the diversity and structure of the methanogenic community inhabiting the anoxic bulk soil of flooded rice microcosms. The molecular approach identified four groups of known methanogens. Three environmental sequences clustered with Methanobacterium bryantii and Methanobacterium formicicum, six were closely related but not identical to those of strains of Methanosaeta concilii, two grouped with members of the genus Methanosarcina, and two were related to the methanogenic endosymbiont of Plagiopyla nasuta. The cultivation approach via most-probable-number counts with a subsample of the same soil as an inoculum yielded cell numbers of up to 107 per g of dry soil for the H2-CO2-utilizing methanogens and of up to 106 for the acetate-utilizing methanogens. Strain VeH52, isolated from the terminal positive dilution on H2-CO2, grouped within the phylogenetic radiation characterized by M. bryantii and M. formicicum and the environmental sequences of the Methanobacterium-like group. A consortium of two distinct methanogens grew in the terminal positive culture on acetate. These two organisms showed absolute 16S rRNA gene identities with environmental sequences of the novel Methanosaeta-like group and the Methanobacterium-like group. Methanosarcina spp. were identified only in the less-dilute levels of the same dilution series on acetate. These data correlate well with acetate concentrations of about 11 μM in the pore water of this rice paddy soil. These concentrations are too low for the growth of known Methanosarcina spp. but are at the acetate utilization threshold of Methanosaeta spp. Thus, our data indicated Methanosaeta spp. and Methanobacterium spp. to be the dominant methanogenic groups in the anoxic rice soil, whereas Methanosarcina spp. appeared to be less abundant. PMID:9501436

  5. The methanogenic redox cofactor F420 is widely synthesized by aerobic soil bacteria.

    PubMed

    Ney, Blair; Ahmed, F Hafna; Carere, Carlo R; Biswas, Ambarish; Warden, Andrew C; Morales, Sergio E; Pandey, Gunjan; Watt, Stephen J; Oakeshott, John G; Taylor, Matthew C; Stott, Matthew B; Jackson, Colin J; Greening, Chris

    2017-01-01

    F420 is a low-potential redox cofactor that mediates the transformations of a wide range of complex organic compounds. Considered one of the rarest cofactors in biology, F420 is best known for its role in methanogenesis and has only been chemically identified in two phyla to date, the Euryarchaeota and Actinobacteria. In this work, we show that this cofactor is more widely distributed than previously reported. We detected the genes encoding all five known F420 biosynthesis enzymes (cofC, cofD, cofE, cofG and cofH) in at least 653 bacterial and 173 archaeal species, including members of the dominant soil phyla Proteobacteria, Chloroflexi and Firmicutes. Metagenome datamining validated that these genes were disproportionately abundant in aerated soils compared with other ecosystems. We confirmed through high-performance liquid chromatography analysis that aerobically grown stationary-phase cultures of three bacterial species, Paracoccus denitrificans, Oligotropha carboxidovorans and Thermomicrobium roseum, synthesized F420, with oligoglutamate sidechains of different lengths. To understand the evolution of F420 biosynthesis, we also analyzed the distribution, phylogeny and genetic organization of the cof genes. Our data suggest that although the Fo precursor to F420 originated in methanogens, F420 itself was first synthesized in an ancestral actinobacterium. F420 biosynthesis genes were then disseminated horizontally to archaea and other bacteria. Together, our findings suggest that the cofactor is more significant in aerobic bacterial metabolism and soil ecosystem composition than previously thought. The cofactor may confer several competitive advantages for aerobic soil bacteria by mediating their central metabolic processes and broadening the range of organic compounds they can synthesize, detoxify and mineralize.

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

    PubMed

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

    2011-10-01

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

  7. Nitrification Is a Primary Driver of Nitrous Oxide Production in Laboratory Microcosms from Different Land-Use Soils

    PubMed Central

    Liu, Rui; Hu, Hangwei; Suter, Helen; Hayden, Helen L.; He, Jizheng; Mele, Pauline; Chen, Deli

    2016-01-01

    Most studies on soil N2O emissions have focused either on the quantifying of agricultural N2O fluxes or on the effect of environmental factors on N2O emissions. However, very limited information is available on how land-use will affect N2O production, and nitrifiers involved in N2O emissions in agricultural soil ecosystems. Therefore, this study aimed at evaluating the relative importance of nitrification and denitrification to N2O emissions from different land-use soils and identifying the potential underlying microbial mechanisms. A 15N-tracing experiment was conducted under controlled laboratory conditions on four agricultural soils collected from different land-use. We measured N2O fluxes, nitrate (NO3-), and ammonium (NH4+) concentration and 15N2O, 15NO3-, and 15NH4+ enrichment during the incubation. Quantitative PCR was used to quantify ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Our results showed that nitrification was the main contributor to N2O production in soils from sugarcane, dairy pasture and cereal cropping systems, while denitrification played a major role in N2O production in the vegetable soil under the experimental conditions. Nitrification contributed to 96.7% of the N2O emissions in sugarcane soil followed by 71.3% in the cereal cropping soil and 70.9% in the dairy pasture soil, while only around 20.0% of N2O was produced from nitrification in vegetable soil. The proportion of nitrified nitrogen as N2O (PN2O-value) varied across different soils, with the highest PN2O-value (0.26‰) found in the cereal cropping soil, which was around 10 times higher than that in other three systems. AOA were the abundant ammonia oxidizers, and were significantly correlated to N2O emitted from nitrification in the sugarcane soil, while AOB were significantly correlated with N2O emitted from nitrification in the cereal cropping soil. Our findings suggested that soil type and land-use might have strongly affected the relative

  8. Non-stereoselective transformation of the chiral insecticide cycloxaprid in aerobic soil.

    PubMed

    Chen, Min; He, Yupeng; Yang, Yatian; Huang, Lei; Zhang, Hanxue; Ye, Qingfu; Wang, Haiyan

    2017-02-01

    Cycloxaprid (CYC) is one of the most effective neonicotinoid insecticides and is proposed to be a replacement of imidacloprid that has caused concerns over non-targeted resistance and ecological toxicity worldwide. The present study was performed with the (14)C-labeled racemic CYC and its two enantiomers in aerobic soil. Racemic CYC and the enantiomers 1S2R-CYC and 1R2S-CYC underwent non-stereoselective degradation in the three soils tested. During the incubation period, CYC was transformed into three achiral degradation products which displayed varying degradation kinetics dependent upon soil properties. The soil properties were found to significantly influence the CYC metabolite profiles. The fastest degradation occurred in loamy soil, whereas the slowest reactions occurred in acidic clay soil. The primary transformation of CYC included cleavage of the oxabridged seven-member ring and CN between chloropyridinylmethyl and imidazalidine ring, carboxylation of the alkene group, and hydroxylation of imidazolidine ring. The results shed light on understanding of CYC degradation and provided useful information for applications and environmental assessments of chiral pesticides.

  9. 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.

  10. Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil

    NASA Astrophysics Data System (ADS)

    Won, Jongho; Borden, Robert C.

    2016-11-01

    Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate > 200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20 g/m3/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil.

  11. 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.

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

    PubMed

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

    2013-02-01

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

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

    PubMed

    Singleton, David R; Richardson, Stephen D; Aitken, Michael D

    2011-11-01

    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.

  14. 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

  15. 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.

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

    SciTech Connect

    Hinchee, R.E.; Ong, S.K. )

    1992-10-01

    A 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 (O[sub 2]) and production of carbon dioxide (CO[sub 2]) 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 O[sub 2]/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 O[sub 2] utilization were generally more reliable (especially for alkaline soils) than rates based on CO[sub 2] production, CO[sub 2] produced from microbial respiration was probably converted to carbonate under alkaline conditions. 14 refs., 5 figs., 4 tabs.

  17. 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.

  18. Induction of the viable but nonculturable state of Ralstonia solanacearum by low temperature in the soil microcosm and its resuscitation by catalase.

    PubMed

    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Fungicide dissipation and impact on metolachlor aerobic soil degradation and soil microbial dynamics.

    PubMed

    White, Paul M; Potter, Thomas L; Culbreath, Albert K

    2010-02-15

    Pesticides are typically applied as mixtures and or sequentially to soil and plants 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 communities. Thus there is a potential to impact soil processes responsible for herbicide degradation. This may change herbicide efficacy and environmental fate characteristics. Our study objective was to determine the effects of 4 peanut fungicides, chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), tebuconazole (alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), flutriafol (alpha-(2-fluorophenyl)-alpha-(4-fluorophenyl)-1H-1,2,4-triazole-1-ethanol), and cyproconazole (alpha-(4-chlorophenyl)-alpha-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol) on the dissipation kinetics of the herbicide, metolachlor (2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide), and on the soil microbial community. This was done through laboratory incubation of field treated soil. Chlorothalonil significantly reduced metolachlor soil dissipation as compared to the non-treated control or soil treated with the other fungicides. Metolachlor DT(50) was 99 days for chlorothalonil-treated soil and 56, 45, 53, and 46 days for control, tebuconazole, flutriafol, and cyproconazole-treated soils, respectively. Significant reductions in predominant metolachlor metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA), produced by oxidation of glutathione-metolachlor conjugates were also observed in chlorothalonil-treated soil. This suggested that the fungicide impacted soil glutathione-S-transferase (GST) activity. Fungicide DT(50) was 27-80 days but impacts on the soil microbial community as indicated by lipid biomarker analysis were minimal. Overall study results indicated that

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

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

    PubMed Central

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

    2016-01-01

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

  7. 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.

  8. Bioremediation of a soil contaminated by hydrocarbon mixtures: the residual concentration problem.

    PubMed

    Nocentini, M; Pinelli, D; Fava, F

    2000-10-01

    The phenomenon of residual concentration was investigated in the aerobic biodegradation of three different petroleum commercial products (i.e., kerosene, diesel fuel and a lubricating mineral oil) in static microcosms. Two different soils exhibiting different physical-chemical characteristics were used (i.e., a biologically treated hydrocarbon-contaminated soil and a pristine soil). Residual concentrations were observed and a simple way to take this phenomenon into account was proposed.

  9. Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil.

    PubMed

    Sánchez-Peinado, María del Mar; González-López, Jesús; Rodelas, Belén; Galera, Vanesa; Pozo, Clementina; Martínez-Toledo, María Victoria

    2008-08-01

    An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.

  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.

  11. 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...

  12. 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

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

    PubMed

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

    2001-01-01

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

  14. 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.

  15. 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

  16. Ozone oxidation and aerobic biodegradation with spent mushroom compost for detoxification and benzo(a)pyrene removal from contaminated soil.

    PubMed

    Russo, Lara; Rizzo, Luigi; Belgiorno, Vincenzo

    2012-05-01

    The combination of ozonation and spent mushroom compost (SMC)-mediated aerobic biological treatment was investigated in the removal of benzo(a)pyrene from contaminated soil. The performances of the process alone and combined were evaluated in terms of benzo(a)pyrene removal efficiency, mineralization efficiency (as total organic carbon removal), and soil residual toxicity (phytotoxicity to Lepidium Sativum and toxicity to Vibrio fischeri). In spite of the removal efficiency (35%) obtained by SMC-mediated biological process as a stand-alone treatment, the combined process showed a benzo(a)pyrene concentration reduction higher than 75%; the best removal (82%) was observed after 10 min pre-ozonation treatment. In particular, ozonation improved the biodegradability of the contaminant, as confirmed by the increase of CO(2) production (close to 70% compared to the control), mineralization (greater than 60%) and bacterial density (which increased by two orders of magnitude). Moreover, according to phytotoxicity tests on L. Sativum, the aerobic biological process of pre-ozonated soil decreased toxicity. According to the results achieved in the present study, ozonation pre-treatment showed an high potential to overcome the limitation of bioremediation of recalcitrant compound, but it should be carefully operated in order to maximize PAH removal efficiency as well as to minimize soil residual toxicity which can result from the formation of the oxidation intermediates.

  17. 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.

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

    PubMed

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

    2015-06-01

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

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

    PubMed

    Ehlers, George A; Rose, Peter D

    2006-07-01

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

  20. 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

  1. 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.

  2. 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).

  3. 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).

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

    PubMed

    Weidhaas, Jennifer; Dupont, R Ryan

    2013-07-01

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

  5. Biodegradation of insensitive munition formulations IMX101 and IMX104 in surface soils.

    PubMed

    Indest, Karl J; Hancock, Dawn E; Crocker, Fiona H; Eberly, Jed O; Jung, Carina M; Blakeney, Gary A; Brame, Jon; Chappell, Mark A

    2017-03-03

    The biodegradation potential of insensitive munition melt cast formulations IMX101 and IMX104 was investigated in two unamended training range soils under aerobic and anaerobic growth conditions. Changes in community profiles in soil microcosms were monitored via high-throughput 16S rRNA sequencing over the course of the experiments to infer key microbial phylotypes that may be linked to IMX degradation. Complete anaerobic biotransformation occurred for IMX101 and IMX104 constituents 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one during the 30-day incubation period with Camp Shelby (CS) soil. By comparison, soil from Umatilla chemical depot demonstrated incomplete DNAN degradation with reduced transformation rates for both IMX101 and IMX104. Aerobic soil microcosms for both soils demonstrated reduced transformation rates compared to anaerobic degradation for all IMX constituents with DNAN the most susceptible to biotransformation by CS soil. Overall, IMX constituents hexahydro-1,3,5-trinitro-1,3,5-triazine and 1-nitroguanidine did not undergo significant transformation. In CS soil, organisms that have been associated with explosives degradation, namely members of the Burkholderiaceae, Bacillaceae, and Paenibacillaceae phylotypes increased significantly in anaerobic treatments whereas Sphingomonadaceae increased significantly in aerobic treatments. Collectively, these data may be used to populate fate and transport models to provide more accurate estimates for assessing environmental costs associated with release of IMX101 and IMX104.

  6. 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...

  7. Microcosm study for revegetation of barren land with wild plants by some plant growth-promoting rhizobacteria.

    PubMed

    Ahn, Tae-Seok; Ka, Jong-Ok; Lee, Geon-Hyoung; Song, Hong-Gyu

    2007-01-01

    Growth promotion of wild plants by some plant growth-promoting rhizobacteria (PGPR) was examined in the microcosms composed of soils collected separately from a grass-covered site and a nongrass-covered site in a lakeside barren area at Lake Paro, Korea. After sowing the seeds of eight kinds of wild plants and inoculation of several strains of PGPR, the total bacterial number and microbial activity were measured during 5 months of study period, and the plant biomasses grown were compared at the end of the study. Acridine orange direct counts in the inoculated microcosms, 1.3-9.8 x 10(9) cells x g soil(-1) in the soil from the grass-covered area and 0.9-7.2 x 10(9) cells x g soil(-1) in the soil from the nongrass-covered site, were almost twice higher than those in the uninoculated microcosms. The number of Pseudomonas sp., well-known bacteria as PGPR, and the soil dehydrogenase activity were also higher in the inoculated soils than the uninoculated soils. The first germination of sowed seeds in the inoculated microcosm was 5 days earlier than the uninoculated microcosm. Average lengths of all plants grown during the study period were 26% and 29% longer in the inoculated microcosms starting with the grass-covered soil and the nongrass-covered soil, respectively, compared with those in the uninoculated microcosms. Dry weights of whole plants grown were 67-82% higher in the inoculated microcosms than the uninoculated microcosms. Microbial population and activity and growth promoting effect by PGPR were all higher in the soils collected from the grass-covered area than in the nongrass-covered area. The growth enhancement of wild plants seemed to occur by the activities of inoculated microorganisms, and this capability of PGPR may be utilized for rapid revegetation of some barren lands.

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

    PubMed Central

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

    2015-01-01

    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 (pre-bioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (post-bioremediation) 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, post-bioremediation, 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 to xicity 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, post-bioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, post-bioremediation (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 post-bioremediation. The increased toxicity measured post-bioremediation 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 post-bioremediation. However, the increased toxicity measured post-bioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs

  9. 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...

  10. 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

  11. 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…

  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. 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

  14. 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.

  15. Biodegradation of N-nitrosodimethylamine in soil from a water reclamation facility

    USGS Publications Warehouse

    Bradley, Paul M.; Carr, Steve A.; Baird, Rodger B.; Chapelle, Francis H.

    2005-01-01

    The potential introduction of N-nitrosodimethylamine (NDMA) into groundwater during water reclamation activities poses a significant risk to groundwater drinking supplies. Greater than 54% biodegradation of N-[methyl-14C]NDMA to 14CO2 or to 14CO2 and 14CH4 was observed in soil from a water reclamation facility under oxic or anoxic conditions, respectively. Likewise, biodegradation was significant in microcosms containing soil with no history of NDMA contamination. These results indicate that aerobic and anaerobic biodegradation of NDMA may be an effective component of NDMA attenuation in water reclamation facility soils.

  16. 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.

  17. 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.

  18. 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

  19. Synergistic relationships in algal-bacterial microcosms for the treatment of aromatic pollutants.

    PubMed

    Borde, Xavier; Guieysse, Benoît; Delgado, Osvaldo; Muñoz, Raúl; Hatti-Kaul, Rajni; Nugier-Chauvin, Caroline; Patin, Henri; Mattiasson, Bo

    2003-02-01

    The potential of algal-bacterial microcosms was studied for the biodegradation of salicylate, phenol and phenanthrene. The isolation and characterization of aerobic bacterial strains capable of mineralizing each pollutant were first conducted. Ralstonia basilensis was isolated for salicylate degradation, Acinetobacter haemolyticus for phenol and Pseudomonas migulae and Sphingomonas yanoikuyae for phenanthrene. The green alga Chlorella sorokiniana was then cultivated in the presence of the pollutants at different concentrations, showing increasing inhibitory effects in the following order: salicylate < phenol < phenanthrene. The synergistic relationships in the algal-bacterial microcosms were clearly demonstrated, since for the three contaminants tested, a substantial removal (>85%) was recorded only in the systems inoculated with both algae and bacteria and incubated under continuous lighting. This study presents, to our knowledge, the first reported case of photosynthesis-enhanced biodegradation of toxic aromatic pollutants by algal-bacterial microcosms in a one-stage treatment.

  20. 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.

  1. 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.

  2. 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.

  3. Spatial and temporal variations in pentachlorophenol dissipation at the aerobic--anaerobic interfaces of flooded paddy soils.

    PubMed

    Lin, Jiajiang; Xu, Yan; Brookes, Philip C; He, Yan; Xu, Jianming

    2013-07-01

    Pentachlorophenol (PCP) dissipation occurs naturally in flooded soils and although dissipation half-lives vary between soil profiles at the millimeter-scale the reason is poorly understood. Vertical variations of PCP dissipation were investigated in three typical Chinese paddy soils; Soil 1 (Umbraqualf), Soil 2 (Plinthudult) and Soil 3 (Tropudult). The soil depth was divided into a surface and a deep layer based upon different PCP dissipations in the surface layer of 40-93, 42-88 and 16-100% for Soils 1-3 respectively. In the deep layer, PCP was greatly dissipated in Soil 2, but much less in Soil 1 and Soil 3. Correlation analysis indicated that SO4(2-) and Fe(III) were negatively related to PCP dissipation. SO4(2-) and Cl(-) were highly mobile in the flooded soil profiles. Fe(III) reduction increased with increasing soil depth, and was inhibited by high SO4(2-) concentrations.

  4. Generation of Perfluoroalkyl Acids from Aerobic Biotransformation of Quaternary Ammonium Polyfluoroalkyl Surfactants.

    PubMed

    Mejia-Avendaño, Sandra; Vo Duy, Sung; Sauvé, Sébastien; Liu, Jinxia

    2016-09-20

    The aerobic biotransformation over 180 days of two cationic quaternary ammonium compounds (QACs) with perfluoroalkyl chains was determined in soil microcosms, and biotransformation pathways were proposed. This is the first time that polyfluoroalkyl cationic surfactants used in aqueous film-forming foam (AFFF) formulations were studied for their environmental fate. The biotransformation of perfluorooctaneamido quaternary ammonium salt (PFOAAmS) was characterized by a DT50 value (time necessary to consume half of the initial mass) of 142 days and significant generation of perfluoroalkyl carboxylic acid (PFOA) at a yield of 30 mol % by day 180. The biotransformation of perfluorooctane sulfonamide quaternary ammonium salt (PFOSAmS) was very slow with unobservable change of the spiked mass; yet the generation of perfluorooctanesulfonate (PFOS) at a yield of 0.3 mol % confirmed the biotransformation of PFOSAmS. Three novel biotransformation intermediates were identified for PFOAAmS and three products including perfluorooctane sulfonamide (FOSA) for PFOSAmS through high-resolution mass spectrometry (MS) analysis and t-MS(2) fragmentation. The significantly slower PFOSAmS biotransformation is hypothesized to be due to its stronger sorption to soil owing to a longer perfluoroalkyl chain and a bulkier sulfonyl group, when compared to PFOAAmS. This study has demonstrated that despite overall high stability of QACs and their biocide nature, the ones with perfluoroalkyl chains can be substantially biotransformed into perfluoroalkyl acids in aerobic soil.

  5. Mutational hot spots in the mitochondrial microcosm

    SciTech Connect

    Paeaebo, S.

    1996-09-01

    Human mitochondria can be seen as a genetic microcosm, located within the macrocosm of the entire cell. In each cell, this microcosm contains a few thousand copies of a circular DNA genome of 16,569 bp that is transmitted between generations, almost exclusively from mother to child. The study of this genetic microcosm holds particular fascination, since it may fore-shadow the coming genetics of the nuclear genome. In the mitochondrial microcosm, the {open_quotes}Human Genome Project{close_quotes} was completed years ago, with the publication of the DNA sequence of an entire mitochondrial genome. In the microcosm, one is thus well into the {open_quotes}postgenomic era.{close_quotes} It therefore may be instructive to ask what the first 15 years of postgenomics has brought within the microcosmic field of mitochondrial genetics. The availability of a complete genome sequence obviously brought great benefits to the study of physiological process in the mitochondria. However, in addition, many insights in the immediately postgenomic phase seem to come from the study of genomic variation. 26 refs.

  6. 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

  7. 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.

  8. 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

  9. Persistence and cell culturability of biocontrol strain Pseudomonas fluorescens CHA0 under plough pan conditions in soil and influence of the anaerobic regulator gene anr.

    PubMed

    Mascher, Fabio; Schnider-Keel, Ursula; Haas, Dieter; Défago, Geneviève; Moënne-Loccoz, Yvan

    2003-02-01

    Certain fluorescent pseudomonads can protect plants from soil-borne pathogens, and it is important to understand how these biocontrol agents survive in soil. The persistence of the biocontrol strain Pseudomonas fluorescens CHA0-Rif under plough pan conditions was assessed in non-sterile soil microcosms by counting total cells (immunofluorescence microscopy), intact cells (BacLight membrane permeability test), viable cells (Kogure's substrate-responsiveness test) and culturable cells (colony counts on selective plates) of the inoculant. Viable but non-culturable cells of CHA0-Rif (106 cells g-1 soil) were found in flooded microcosms amended with fermentable organic matter, in which the soil redox potential was low (plough pan conditions), in agreement with previous observations of plough pan samples from a field inoculated with CHA0-Rif. However, viable but non-culturable cells were not found in unamended flooded, amended unflooded or unamended unflooded (i.e. control) microcosms, suggesting that such cells resulted from exposure of CHA0-Rif to a combination of low redox potential and oxygen limitation in soil. CHA0-Rif is strictly aerobic. Its anaerobic regulator ANR is activated by low oxygen concentrations and it controls production of the biocontrol metabolite hydrogen cyanide under microaerophilic conditions. Under plough pan conditions, an anr-deficient mutant of CHA0-Rif and its complemented derivative displayed the same persistence pattern as CHA0-Rif, indicating that anr was not implicated in the formation of viable but non-culturable cells of this strain at the plough pan.

  10. Bioremediation of diesel and lubricant oil-contaminated soils using enhanced landfarming system.

    PubMed

    Wang, Sih-Yu; Kuo, Yu-Chia; Hong, Andy; Chang, Yu-Min; Kao, Chih-Ming

    2016-12-01

    Lubricant and diesel oil-polluted sites are difficult to remediate because they have less volatile and biodegradable characteristics. The goal of this research was to evaluate the potential of applying an enhanced landfarming to bioremediate soils polluted by lubricant and diesel. Microcosm study was performed to evaluate the optimal treatment conditions with the addition of different additives (nutrients, addition of activated sludge from oil-refining wastewater facility, compost, TPH-degrading bacteria, and fern chips) to enhance total petroleum hydrocarbon (TPH) removal. To simulate the aerobic landfarming biosystem, air in the microcosm headspace was replaced once a week. Results demonstrate that the additives of activated sludge and compost could result in the increase in soil microbial populations and raise TPH degradation efficiency (up to 83% of TPH removal with 175 days of incubation) with initial (TPH = 4100 mg/kg). The first-order TPH degradation rate reached 0.01 1/d in microcosms with additive of activated sludge (mass ratio of soil to inocula = 50:1). The soil microbial communities were determined by nucleotide sequence analyses and 16S rRNA-based denatured gradient gel electrophoresis. Thirty-four specific TPH-degrading bacteria were detected in microcosm soils. Chromatograph analyses demonstrate that resolved peaks were more biodegradable than unresolved complex mixture. Results indicate that more aggressive remedial measures are required to enhance the TPH biodegradation, which included the increase of (1) microbial population or TPH-degrading bacteria, (2) biodegradable carbon sources, (3) nutrient content, and (4) soil permeability.

  11. Toxicity to freshwater organisms from oils and oil spill chemical treatments in laboratory microcosms.

    PubMed

    Bhattacharyya, S; Klerks, P L; Nyman, J A

    2003-01-01

    Toxicity and temporal changes in toxicity of freshwater-marsh-microcosms containing South Louisiana Crude (SLC) or diesel fuel and treated with a cleaner or dispersant, were investigated using Chironomus tentans, Daphnia pulex, and Oryzias latipes. Bioassays used microcosm water (for D. pulex and O. latipes) or soil slurry (for C. tentans) taken 1,7, 31, and 186 days after treatment. SLC was less toxic than diesel, chemical additives enhanced oil toxicity, the dispersant was more toxic than the cleaner, and toxicities were greatly reduced by day 186. Toxicities were higher in the bioassay with the benthic species than in those with the two water-column species. A separate experiment showed that C. tentans' sensitivity was intermediate to that of Tubifex tubifex and Hyallela azteca. Freshwater organisms, especially benthic invertebrates, thus appear seriously effected by oil under the worst-case-scenario of our microcosms. Moreover, the cleaner and dispersant tested were poor response options under those conditions.

  12. Biostimulation of indigenous microorganisms for bioremediation of oily hypersaline microcosms from the Arabian Gulf Kuwaiti coasts.

    PubMed

    Al-Mailem, Dina M; Al-Deieg, Maha; Eliyas, Mohamed; Radwan, Samir S

    2017-05-15

    Hypersaline soil and water samples were collected in summer and winter from the "sabkha" area at the Kuwaiti shore of the Arabian Gulf. Physicochemical parameters were analyzed, and found suitable for microbial oil-removal. Summer- and winter-microcosms were treated with individual cation (K(+), Ca(2+), Mg(2+), Fe(3+)) salts, and with animal blood and commercial yeast, as cost-effective vitamin sources. Those microcosms were exposed to the open environment for six winter and six summer months, and analyzed for their hydrocarbonoclastic microorganisms at time zero and in two month intervals. The hydrocarbonoclastic microbial communities in the microcosms consisted of halophilic bacteria and haloarchaea. The constituent bacterial species varied according to the season. Three species, Dietzia kunjamensis, Marinobacter lacisalsi and Halomonas oxialensis consistently occurred both in summer- and winter-samples, but the remaining species were different. On the other hand, the haloarchaeal communities in summer and winter were quite similar, and consisted mainly of Haloferax spp and Halobacterium spp. Treating the microcosms with cations and with vitamin-containing natural products enhanced microbial numbers and oil-removal. The effectiveness of the cations in oil-removal was in the order; Fe(3+) (94%) > Ca(2+) (89%) > Mg(2+) (85%) > K(+) (82%). Thus, oily microcosms amended with trivalent and divalent cations lost most of the oil, and those amended with commercial yeast and with animal blood, as vitamin sources, lost 78% and 72% oil, respectively.

  13. 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.

  14. Effect of elevated temperature and enhanced drainage on carbon balance of tundra microcosms

    SciTech Connect

    Johnson, L.C.; Shaver, G.R.; Giblin, A.E.; Nadelhoffer, K.J.; Rastetter, E.B.; Laundre, J.A.; Murray, G.L. )

    1994-06-01

    We tested effects of temperature and drainage on C balance of intact soil and tundra vegetation over a simulated season. We measured C budgets (CO[sub 2] and CH[sub 4] emissions and dissolved CO[sub 2], CH[sub 4] and DOC in soil water) of Eriophorum vaginatum tussock and moss-dominated interussock microcosms at two temperatures (7[degrees] and 15[degrees]C, season maxima) and two water regimes (saturated and field capacity). Net ecosystem productivity was strongly affected by water. Averaged over temperature and microhabitat, the rate of net C loss from microcosms at field capacity was [approximately]5[times] the saturated microcosms. Only saturated, 15[degrees]C tussock microcosms showed net C storage integrated over the whole season. Ecosystem respiration was strongly affected by water and less by temperature. Respiration rates at field capacity were [approximately]2[times] the rates under saturated conditions. Elevated temperature caused a 1.5[times] increase. Other C components were <20% of gaseous CO[sub 2] losses. Results indicate that C in tundra exists in a fragile balance between storage and release that is controlled mainly by water regime.

  15. Aerobic Tennis.

    ERIC Educational Resources Information Center

    Stewart, Michael J.; Ahlschwede, Robert

    1989-01-01

    Increasing the aerobic nature of tennis drills in the physical education class may be necessary if tennis is to remain a part of the public school curriculum. This article gives two examples of drills that can be modified by teachers to increase activity level. (IAH)

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-08-01

    A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76(T), was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6-0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76(T) had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76(T) had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76(T) is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85% 16S rRNA gene sequence identity with the closest cultivated relative 'Candidatus Nitrosopumilus maritimus' SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81% 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. 'Korarchaeota' and 'Aigarchaeota'). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76(T). The type strain of Nitrososphaera viennensis is strain EN76(T) ( = DSM 26422(T) = JMC 19564(T)). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov.

  18. MODELING EUTROPHICATION KINETICS IN RESERVOIR MICROCOSMS

    EPA Science Inventory

    This study addresses the question of how a general seasonal eutrophication model, WASP5, can handle daily phytoplankton and nutrient dynamics in perturbed microcosms for 1-to 2-week periods of time. It is intended to explore both the interpretative and the predictive capabilities...

  19. Fertilization stimulates anaerobic fuel degradation of antarctic soils by denitrifying microorganisms.

    PubMed

    Powell, Shane M; Ferguson, Susan H; Snape, Ian; Siciliano, Steven D

    2006-03-15

    Human activities in the Antarctic have resulted in hydrocarbon contamination of these fragile polar soils. Bioremediation is one of the options for remediation of these sites. However, little is known about anaerobic hydrocarbon degradation in polar soils and the influence of bioremediation practices on these processes. Using a field trial at Old Casey Station, Antarctica, we assessed the influence of fertilization on the anaerobic degradation of a 20-year old fuel spill. Fertilization increased hydrocarbon degradation in both anaerobic and aerobic soils when compared to controls, but was of most benefit for anaerobic soils where evaporation was negligible. This increased biodegradation in the anaerobic soils corresponded with a shift in the denitrifier community composition and an increased abundance of denitrifiers and benzoyl-CoA reductase. A microcosm study using toluene and hexadecane confirmed the degradative capacity within these soils under anaerobic conditions. It was observed that fertilized anaerobic soil degraded more of this hydrocarbon spike when incubated anaerobically than when incubated aerobically. We conclude that denitrifiers are actively involved in hydrocarbon degradation in Antarctic soils and that fertilization is an effective means of stimulating their activity. Further, when communities stimulated to degrade hydrocarbons under anaerobic conditions are exposed to oxygen, hydrocarbon degradation is suppressed. The commonly accepted belief that remediation of polar soils requires aeration needs to be reevaluated in light of this new data.

  20. 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.

  1. Influence of oxic/anoxic fluctuations on ammonia oxidizers and nitrification potential in a wet tropical soil.

    PubMed

    Pett-Ridge, Jennifer; Petersen, Dorthe G; Nuccio, Erin; Firestone, Mary K

    2013-07-01

    Ammonia oxidation is a key process in the global nitrogen cycle. However, in tropical soils, little is known about ammonia-oxidizing microorganisms and how characteristically variable oxygen regimes affect their activity. We investigated the influence of brief anaerobic periods on ammonia oxidation along an elevation, moisture, and oxygen availability gradient in wet tropical soils. Soils from three forest types were incubated for up to 36 weeks in lab microcosms under three regimes: (1) static aerobic; (2) static anaerobic; and (3) fluctuating (aerobic/anaerobic). Nitrification potential was measured in field-fresh soils and incubated soils. The native ammonia-oxidizing community was also characterized, based on diversity assessments (clone libraries) and quantification of the ammonia monooxygenase α-subunit (amoA) gene. These relatively low pH soils appear to be dominated by ammonia-oxidizing archaea (AOA), and AOA communities in the three soil types differed significantly in their ability to oxidize ammonia. Soils from an intermediate elevation, and those incubated with fluctuating redox conditions, tended to have the highest nitrification potential following an influx of oxygen, although all soils retained the capacity to nitrify even after long anoxic periods. Together, these results suggest that wet tropical soil AOA are tolerant of extended periods of anoxia.

  2. Laboratory, Field, and Modeling Studies of Aerobic Cometabolism of CAHs by Butane-Utilizing Microorganisms

    NASA Astrophysics Data System (ADS)

    Mathias, M.; Semprini, L.; Dolan, M. E.; McCarty, P. L.; Hopkins, G. D.

    2002-12-01

    The ability of butane-utilizing microorganisms to aerobically cometabolize a mixture of chlorinated aliphatic hydrocarbons (CAHs) in laboratory microcosms and in an in-situ field demonstration was modeled using parameter values measured in laboratory experiments. The butane grown culture was inoculated into soil and groundwater microcosms and exposed to butane with several repeated additions of 1,1,1-trichloroethane (TCA), 1,1-dichloroethylene (1,1-DCE), and 1,1-dichloroethane (1,1-DCA) at aqueous concentrations of 200 μg/L, 100 μg/L, and 200 μg/L, respectively. The utilization of butane and the transformation of the CAH mixture in the batch microcosms were simulated using differential equations accounting for Michaelis-Menten kinetics with cell growth and decay, substrate utilization, transformation product toxicity, and substrate inhibition of CAH transformation. Both competitive inhibition kinetics and mixed inhibition kinetics, determined in prior laboratory studies, were included in the model construct. The equations were solved simultaneously using fourth-order Runge-Kutta numerical integration. The batch microcosm experimental results were simulated well with parameter values determined independently in culture kinetic studies, with some minor adjustments. Having adequately defined the parameter values from laboratory studies, the biotransformation model was combined with 1-D advective-dispersive transport to simulate the results of in-situ bioremediation tests conducted at the Moffett Field Test Facility in CA. The butane-utilizing culture was injected into a 7 m subsurface test site and exposed to alternating pulses of oxygen and butane, along with TCA (150 μg/L), 1,1-DCE (50 μg/L) and 1,1-DCA (150 μg/L). The model simulated well the transient transformation of the CAHs in response to different butane and oxygen pulse cycles and injection concentrations. Model simulations correlated well with field results and indicated that better remediation

  3. Aerobic cometabolic degradation of trichloroethene by methane and ammonia oxidizing microorganisms naturally associated with Carex comosa roots.

    PubMed

    Powell, C L; Nogaro, G; Agrawal, A

    2011-06-01

    The degradation potential of trichloroethene by the aerobic methane- and ammonia-oxidizing microorganisms naturally associated with wetland plant (Carex comosa) roots was examined in this study. In bench-scale microcosm experiments with washed (soil free) Carex comosa roots, the activity of root-associated methane- and ammonia-oxidizing microorganisms, which were naturally present on the root surface and/or embedded within the roots, was investigated. Significant methane and ammonia oxidation were observed reproducibly in batch reactors with washed roots incubated in growth media, where methane oxidation developed faster (2 weeks) compared to ammonia oxidation (4 weeks) in live microcosms. After enrichment, the methane oxidizers demonstrated their ability to degrade 150 μg l(-1) TCE effectively at 1.9 mg l(-1) of aqueous CH(4). In contrast, ammonia oxidizers showed a rapid and complete inhibition of ammonia oxidation with 150 μg l(-1) TCE at 20 mg l(-1) of NH(4)(+)-N, which may be attributed to greater sensitivity of ammonia oxidizers to TCE or its degradation product. No such inhibitory effect of TCE degradation was detected on methane oxidation at the above experimental conditions. The results presented here suggest that microorganisms associated with wetland plant roots can assist in the natural attenuation of TCE in contaminated aquatic environments.

  4. 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.

  5. 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

  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. 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

  8. Concomitant aerobic biodegradation of benzene and thiophene

    SciTech Connect

    Dyreborg, S.; Arvin, E.; Broholm, K.

    1998-05-01

    The concomitant aerobic biodegradation of benzene and thiophene was investigated in microcosm experiments using a groundwater enrichment culture. Benzene was biodegraded within 1 d, whereas thiophene could not be biodegraded as the sole source of carbon and energy. Some interesting phenomena were observed when both benzene and thiophene were present. In most cases, removal of thiophene was observed, and the removal occurred concomitantly with the biodegradation of benzene, suggesting that benzene was used as a primary substrate in the cometabolic biodegradation of thiophene. No biodegradation of the two compounds was observed for some combinations of concentrations, suggesting that thiophene could act as an inhibitor to benzene biodegradation. However, this effect could be overcome if more benzene was added to the microcosm. Residual concentrations of benzene and thiophene were observed in some microcosms and the data indicated that the biodegradation of the two compounds stopped when a critical threshold ratio between the concentrations of thiophene and benzene was reached. This ratio varied between 10 and 20. Results from modeling the biodegradation data suggested that thiophene was cometabolized concomitantly with the biodegradation of benzene and that the biodegradation may be described by a modified model based on a traditional model with an inhibition term incorporated.

  9. 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).

  10. Novel cellulose-binding domains, NodB homologues and conserved modular architecture in xylanases from the aerobic soil bacteria Pseudomonas fluorescens subsp. cellulosa and Cellvibrio mixtus.

    PubMed Central

    Millward-Sadler, S J; Davidson, K; Hazlewood, G P; Black, G W; Gilbert, H J; Clarke, J H

    1995-01-01

    To test the hypothesis that selective pressure has led to the retention of cellulose-binding domains (CBDs) by hemicellulase enzymes from aerobic bacteria, four new xylanase (xyn) genes from two cellulolytic soil bacteria, Pseudomonas fluorescens subsp. cellulosa and Cellvibrio mixtus, have been isolated and sequenced. Pseudomonas genes xynE and xynF encoded modular xylanases (XYLE and XYLF) with predicted M(r) values of 68,600 and 65000 respectively. XYLE contained a glycosyl hydrolase family 11 catalytic domain at its N-terminus, followed by three other domains; the second of these exhibited sequence identity with NodB from rhizobia. The C-terminal domain (40 residues) exhibited significant sequence identity with a non-catalytic domain of previously unknown function, conserved in all the cellulases and one of the hemicellulases previously characterized from the pseudomonad, and was shown to function as a CBD when fused to the reporter protein glutathione-S-transferase. XYLF contained a C-terminal glycosyl hydrolase family 10 catalytic domain and a novel CBD at its N-terminus. C. mixtus genes xynA and xynB exhibited substantial sequence identity with xynE and xynF respectively, and encoded modular xylanases with the same molecular architecture and, by inference, the same functional properties. In the absence of extensive cross-hybridization between other multiple cel (cellulase) and xyn genes from P. fluorescens subsp. cellulosa and genomic DNA from C. mixtus, similarity between the two pairs of xylanases may indicate a recent transfer of genes between the two bacteria. Images Figure 1 Figure 4 PMID:7492333

  11. 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

  12. 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.

  13. Microcosm studies of subsurface PAH-degrading bacteria from a former manufactured gas plant

    NASA Astrophysics Data System (ADS)

    Durant, Neal D.; Wilson, Liza P.; Bouwer, Edward J.

    1995-01-01

    A study was conducted to evaluate the potential for natural in situ biodegradation of polycyclic aromatic hydrocarbons (PAH's) in the subsurface at the site of a former manufactured gas plant. Fifty-seven samples of unconsolidated subsurface sediments were aseptically obtained from five boreholes across the site. Bacteria capable of aerobically degrading PAH's without an acclimation period were detected throughout shallow (2.7 m) and deep (24.7 m) areas of the subsurface in both relatively clean (<20 μg L -1 naphthalene) and contaminated (4400 μg L -1 naphthalene) zones. Significant ( p < 0.05) quantities of naphthalene (8±3% to 43±7%) and/or phenanthrene (3±1% to 31±3%) were mineralized in sediment-groundwater microcosms during 4 weeks of aerobic incubation at 22°C. Three samples out of 11 were able to aerobically mineralize significant quantities of benzene (6±2% to 24±1%). Of 11 samples tested for anaerobic mineralization, naphthalene biodegradation (7±1% to 13±2%) in the presence of N03 was observed in two samples. Compound removals were first order with respect to substrate concentration during the first 10-15 days of incubation. Compound biodegradation plateaued in the later stages of incubation (15-40 days), most likely from diminishing bioavailability and nutrient and oxygen depletion. Population densities in the sediments were typically low, with viable aerobic counts ranging from 0 to 10 5 CFU gdw -1, viable anaerobic counts ranging from 0 to 104 CFU gdw -1, and total counts (AODC) usually 10-fold greater than viable counts. Total counts exhibited a strong ( p < 0.01) positive correlation with sample grain size. Viable aerobic and anaerobic populations commonly occurred in the same sample, suggesting the presence of facultative anaerobes. Bacteria were metabolically active in samples from groundwaters with low pH (3.7) and high naphthalene concentrations (11,000 μg L -1). Data from these enumeration and microcosm studies suggest that natural

  14. Laboratory-scale evaluation of a combined soil amendment for the enhanced biodegradation of propylene glycol-based aircraft de-icing fluids.

    PubMed

    Libisch, Balázs; French, Helen K; Hartnik, Thomas; Anton, Attila; Biró, Borbála

    2012-01-01

    A combined soil amendment was tested in microcosm experiments with an aim to enhance the aerobic biodegradation of propylene glycol (PG)-based aircraft de-icing fluids during and following the infiltration of contaminated snowmelt. A key objective under field conditions is to increase degradation of organic pollutants in the surface soil where higher microbial activity and plant rhizosphere effects may contribute to a more efficient biodegradation of PG, compared to subsoil ground layers, where electron acceptors and nutrients are often depleted. Microcosm experiments were set up in Petri dishes using 50 g of soil mixed with appropriate additives. The samples contained an initial de-icing fluid concentration of 10,000 mg/kg soil. A combined amendment using calcium peroxide, activated carbon and 1 x Hoagland solution resulted in significantly higher degradation rates for PG both at 4 and 22 degrees C. Most probable numbers of bacteria capable of utilizing 10,000 mg/kg de-icing fluid as a sole carbon source were about two orders of magnitude higher in the amended soil samples compared to unamended controls at both temperatures. The elevated numbers of such bacteria in surface soil may be a source of cells transported to the subsoil by snowmelt infiltration. The near-surface application of amendments tested here may enhance the growth of plants and plant roots in the contaminated area, as well as microbes to be found at greater depth, and hence increase the degradation of a contaminant plume present in the ground.

  15. Molecular analysis of microbial community structures in pristine and contaminated aquifers--Field and laboratory microcosm experiments

    USGS Publications Warehouse

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

    1999-01-01

    Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experimentsvar callbackToken='531E8ACDB6C8511'; var subCode='asmjournal_sub'; var OAS_sitepage = 'aem.asm.org'; 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 predominantlyBacteria; 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

  16. 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.

  17. Enhancing aerobic biodegradation of 1,2-dibromoethane in groundwater using ethane or propane and inorganic nutrients

    NASA Astrophysics Data System (ADS)

    Hatzinger, Paul B.; Streger, Sheryl H.; Begley, James F.

    2015-01-01

    1,2-Dibromoethane (ethylene dibromide; EDB) is a probable human carcinogen that was previously used as both a soil fumigant and a scavenger in leaded gasoline. EDB has been observed to persist in soils and groundwater, particularly under oxic conditions. The objective of this study was to evaluate options to enhance the aerobic degradation of EDB in groundwater, with a particular focus on possible in situ remediation strategies. Propane gas and ethane gas were observed to significantly stimulate the biodegradation of EDB in microcosms constructed with aquifer solids and groundwater from the FS-12 EDB plume at Joint Base Cape Cod (Cape Cod, MA), but only after inorganic nutrients were added. Ethene gas was also effective, but rates were appreciably slower than for ethane and propane. EDB was reduced to < 0.02 μg/L, the Massachusetts state Maximum Contaminant Level (MCL), in microcosms that received ethane gas and inorganic nutrients. An enrichment culture (BE-3R) that grew on ethane or propane gas but not EDB was obtained from the site materials. The degradation of EDB by this culture was inhibited by acetylene gas, suggesting that degradation is catalyzed by a monooxygenase enzyme. The BE-3R culture was also observed to biodegrade 1,2-dichloroethane (DCA), a compound commonly used in conjunction with EDB as a lead scavenger in gasoline. The data suggest that addition of ethane or propane gas with inorganic nutrients may be a viable option to enhance degradation of EDB in groundwater aquifers to below current state or federal MCL values.

  18. 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.

  19. 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.

  20. 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.

  1. 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;…

  2. 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.

  3. 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.

  4. 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.

  5. Biomarker response and biomass change of earthworms exposed to chlorpyrifos in microcosms.

    PubMed

    Reinecke, S A; Reinecke, A J

    2007-01-01

    Background levels of chlorpyrifos and earthworm abundance were determined in an orchard and adjacent areas on a farm in the Western Cape, South Africa before these areas were again sprayed with this organophosphate. The background concentrations ranged from 0.2 microg/kg dm in the spray drift area adjacent to the orchard to 10.18 microg/kg dm on the slope in the run off area. In the target area the chlorpyrifos concentrations varied from a mean of 15.25 +/- 10.0 microg/kg directly after spraying to a mean of 7.0 +/- 0.9 microg/kg 6 months later and in the nontarget area they varied from a mean of 55.0 +/- 35 microg/kg to 12.0 +/- 5 microg/kg after 6 months. Chlorpyrifos was therefore still present in the field soils, but at lower concentrations, up to 6 months after the last spraying event. Earthworm abundance and population densities were very low. Only Aporrectodea caliginosa was found and the densities were much lower in the orchards (22 per m(2)) than in the nontarget areas (98.3 per m(2)). Microcosm studies were undertaken to relate biomarker responses to chlorpyrifos with biomass changes. Microcosms were filled with soil from the same areas and earthworms of the species A. caliginosa were introduced. The microcosms were treated with a series of concentrations of chlorpyrifos in the laboratory under controlled conditions. These concentrations were chosen to fall within the background ranges found in the soils. The biomass of the worms was determined regularly for a period of 5 weeks and worms in a state of estivation were noted. Earthworms were removed from the microcosms for biomarker tests: for cholinesterase (ChE) inhibition assays every week and for a neutral red retention determination 2 weeks after the exposures started. The most prominent biomass loss was noted in earthworms exposed to the highest pesticide concentration of 8.0 microg/kg. Estivation was higher among earthworms exposed to higher exposure concentrations. Inhibition of ChE increased with

  6. Biodegradation of high concentrations of mixed polycyclic aromatic hydrocarbons by indigenous bacteria from a river sediment: a microcosm study and bacterial community analysis.

    PubMed

    Muangchinda, Chanokporn; Yamazoe, Atsushi; Polrit, Duangporn; Thoetkiattikul, Honglada; Mhuantong, Wuttichai; Champreda, Verawat; Pinyakong, Onruthai

    2017-02-01

    This study assessed the biodegradation of mixtures of polycyclic aromatic hydrocarbons (PAHs) by indigenous bacteria in river sediment. Microcosms were constructed from sediment from the Chao Phraya River (the main river in Thailand) by supplementation with high concentrations of fluorene, phenanthrene, pyrene (300 mg kg(-1) of each PAH), and acenaphthene (600 mg kg(-1)). Fluorene and phenanthrene were completely degraded, whereas 50% of the pyrene and acenaphthene were removed at the end of the incubation period (70 days). Community analyses revealed the dynamics of the bacterial profiles in the PAH-degrading microcosms after PAH exposure. Actinobacteria predominated and became significantly more abundant in the microcosms after 14 days of incubation at room temperature under aerobic conditions. Furthermore, the remaining PAHs and alpha diversity were positively correlated. The sequencing of clone libraries of the PAH-RHDα genes also revealed that the dioxygenase genes of Mycobacterium sp. comprised 100% of the PAH-RHDα library at the end of the microcosm setup. Moreover, two PAH-degrading Actinobacteria (Arthrobacter sp. and Rhodococcus ruber) were isolated from the original sediment sample and showed high activity in the degradation of phenanthrene and fluorene in liquid cultivation. This study reveals that indigenous bacteria had the ability to degrade high concentrations of mixed PAHs and provide clear evidence that Actinobacteria may be potential candidates to play a major role in PAH degradation in the river sediment.

  7. Microcosm N2O emissions wth calibration

    EPA Pesticide Factsheets

    The dataset consists of measurements of soil nitrous oxide emissions from soils under three different amendments: glucose, cellulose, and manure. Data includes the four isotopomers of nitrous oxide (14N15N16O, 15N14N16O, 14N14N18O, 14N14N16O), and the site preference.This dataset is associated with the following publication:Chen , H., D. Williams , P. Deshmukh , F. Birgand, B. Maxwell, and J. Walker. Probing the Biological Sources of Soil N2O Emissions by Quantum Cascade Laser-Based 15N Isotopocule Analysis. SOIL SCIENCE SOCIETY OF AMERICA JOURNAL. Soil Science Society of America, Madison, WI, USA, 100(0): 175-181, (2016).

  8. Temporal dynamics of microbial communities in microcosms in response to pollutants.

    PubMed

    Jiao, Shuo; Zhang, Zhengqing; Yang, Fan; Lin, Yanbing; Chen, Weimin; Wei, Gehong

    2017-02-01

    Elucidating the mechanisms underlying microbial succession is a major goal of microbial ecology research. Given the increasing human pressure on the environment and natural resources, responses to the repeated introduction of organic and inorganic pollutants are of particular interest. To investigate the temporal dynamics of microbial communities in response to pollutants, we analysed the microbial community structure in batch microcosms that were inoculated with soil bacteria following exposure to individual or combined pollutants (phenanthrene, n-octadecane, phenanthrene + n-octadecane and phenanthrene + n-octadecane + CdCl2 ). Subculturing was performed at 10-day intervals, followed by high-throughput sequencing of 16S rRNA genes. The dynamics of microbial communities in response to different pollutants alone and in combination displayed similar patterns during enrichment. Specifically, the repression and induction of microbial taxa were dominant, and the fluctuation was not significant. The rate of appearance for new taxa and the temporal turnover within microbial communities were higher than the rates reported in other studies of microbial communities in air, water and soil samples. In addition, conditionally rare taxa that were specific to the treatments exhibited higher betweenness centrality values in the co-occurrence network, indicating a strong influence on other interactions in the community. These results suggest that the repeated introduction of pollutants could accelerate microbial succession in microcosms, resulting in the rapid re-equilibration of microbial communities.

  9. Development of Effective Aerobic Cometabolic Systems for the In Situ Transformation of Problematic Chlorinated Solvent Mixtures

    DTIC Science & Technology

    2005-02-01

    microorganism, Burkholderia cepacia ENV435 was reported by Steffan et al (1999). In that work, groundwater contaminated with 1000-2500 µg/L...aerobic cometabolism of TCE could be accomplished through bioaugmentation of a genetically modified strain of Burkholderia cepacia G4 (McCarty et al...Enhancement of Trichlorethylene Degradation in Aquifer Microcosms Bioagumented with Wild Type and Genetically Altered Burkholderia (Pseudomonas) cepacia G4

  10. Reduction of nitrate in aquifer microcosms by carbon additions

    USGS Publications Warehouse

    Obenhuber, Donald C.; Lowrance , Richard

    1991-01-01

    Aquifer microcosms were used to examine the effects of NO−3 and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L−1 in aquifer microcosms were reduced 0.92%/d to 5.84 mg L−1 by the addition of 10 mg C L−1 for 35 d. Nitrate disappearance correlated with increases in number of denitrifiers and dissolved N2O concentration and decreases in dissolved oxygen, suggesting biological denitrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L−1 added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L−1 had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N2O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO−3 contaminated aquifers by organic infusion is possible and appears to be a function of microbial denitrification.

  11. 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

  12. Degradation mechanisms of DDX induced by the addition of toluene and glycerol as cosubstrates in a zero-valent iron pretreated soil.

    PubMed

    Velasco, Antonio; Aburto-Medina, Arturo; Shahsavari, Esmaeil; Revah, Sergio; Ortiz, Irmene

    2017-01-05

    Abiotic and biotic processes can be used to remediate DDX (DDT, DDD, DDE, and DDNS) contaminated soils; these processes can be fostered using specific carbon-amendments to stimulate particular soil indigenous microbial communities to improve rates or extent of degradation. In this study, toluene and glycerol were evaluated as cosubstrates under aerobic and anoxic conditions to determine the degradation efficiencies of DDX and to elucidate possible degradation mechanisms. Slurry microcosms experiments were performed during 60 days using pretreated soil with zero-valent iron (ZVI). Toluene addition enhanced the percentage of degradation of DDX. DDNS was the main compound degraded (around 86%) under aerobic conditions, suggesting cometabolic degradation of DDX by toluene-degrading soil bacteria. Glycerol addition under anoxic conditions favored the abiotic degradation of DDX mediated by sulfate-reducing bacteria activity, where DDT was the main compound degraded (around 90%). The 16S rDNA metagenomic analyses revealed Rhodococcus ruber and Desulfosporosinus auripigmenti as the predominant bacterial species after 40 days of treatment with toluene and glycerol additions, respectively. This study provides evidence of biotic and abiotic DDX degradation by the addition of toluene and glycerol as cosubstrates in ZVI pretreated DDX-contaminated soil.

  13. PCB dechlorination enhancement in Anacostia River sediment microcosms.

    PubMed

    Krumins, Valdis; Park, Joong-Wook; Son, Eun-Kyeu; Rodenburg, Lisa A; Kerkhof, Lee J; Häggblom, Max M; Fennell, Donna E

    2009-10-01

    In situ treatment of PCB contaminated sediments via microbial dechlorination is a promising alternative to dredging, which may be reserved for only the most contaminated areas. Reductive dechlorination of low levels of weathered PCB mixtures typical of urban environments may occur at slow rates. Here, we report that biostimulation and bioaugmentation enhanced dechlorination of low concentration (2.1 mg PCBs/kg dry weight) historical PCBs in microcosms prepared with Anacostia River, Washington, DC, sediment. Treatments included electron donors butyrate, lactate, propionate and acetate (1 mM each); alternate halogenated electron acceptors (haloprimers) tetrachlorobenzene (TeCB, 25 microM), pentachloronitrobenzene (PCNB, 25 microM), or 2,3,4,5,6-PCB (PCB116, 2.0 microM); and/or bioaugmentation with a culture containing Dehalococcoides ethenogenes strain 195 (3 x 10(6)cells/mL). Dechlorination rates were enhanced in microcosms receiving bioaugmentation, PCNB and PCNB plus bioaugmentation, compared to other treatments. Microcosm subcultures generated after 415 days and spiked with PCB116 showed sustained capacity for dechlorination of PCB116 in PCNB, PCNB plus bioaugmentation, and TeCB treatments, relative to other treatments. Analysis of Chloroflexi 16S rRNA genes showed that TeCB and PCNB increased native Dehalococcoides spp. from the Pinellas subgroup; however this increase was correlated to enhanced dechlorination of low concentration weathered PCBs only in PCNB-amended microcosms. D. ethenogenes strain 195 was detected only in bioaugmented microcosms and decreased over 281 days. Bioaugmentation with D. ethenogenes strain 195 increased PCB dechlorination rates initially, but enhanced capacity for dechlorination of a model congener, PCB116, after 415 days occurred only in microcosms with enhanced native Dehalococcoides spp.

  14. Responses of the Anaerobic Bacterial Community to Addition of Organic C in Chromium(VI)- and Iron(III)-Amended Microcosms

    PubMed Central

    Kourtev, Peter S.; Nakatsu, Cindy H.; Konopka, Allan

    2006-01-01

    Chromium (VI) is toxic to microorganisms and can inhibit the biodegradation of organic pollutants in contaminated soils. We used microcosms amended with either glucose or protein (to drive bacterial community change) and Fe(III) (to stimulate iron-reducing bacteria) to study the effect of various concentrations of Cr(VI) on anaerobic bacterial communities. Microcosms were destructively sampled based on microbial activity (measured as evolution of CO2) and analyzed for the following: (i) dominant bacterial community by PCR-denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene; (ii) culturable Cr-resistant bacteria; and (iii) enrichment of iron-reducing bacteria of the Geobacteraceae family by real-time PCR. The addition of organic C stimulated the activities of anaerobic communities. Cr(VI) amendment resulted in lower rates of CO2 production in glucose microcosms and a slow mineralization phase in protein-amended microcosms. Glucose and protein amendments selected for different bacterial communities. This selection was modified by the addition of Cr(VI), since some DGGE bands were intensified and new bands appeared in Cr(VI)-amended microcosms. A second dose of Cr(VI), added after the onset of activity, had a strong inhibitory effect when higher levels of Cr were added, indicating that the developing Cr-resistant communities had a relatively low tolerance threshold. Most of the isolated Cr-resistant bacteria were closely related to previously studied Cr-resistant anaerobes, such as Pantoea, Pseudomonas, and Enterobacter species. Geobacteraceae were not enriched during the incubation. The studied Cr(VI)-contaminated soil contained a viable anaerobic bacterial community; however, Cr(VI) altered its composition, which could affect the soil biodegradation potential. PMID:16391100

  15. Impact of lime, nitrogen and plant species on bacterial community structure in grassland microcosms.

    PubMed

    Kennedy, Nabla; Brodie, Eoin; Connolly, John; Clipson, Nicholas

    2004-10-01

    A microcosm-based approach was used to study impacts of plant and chemical factors on the bacterial community structure of an upland acidic grassland soil. Seven perennial plant species typical of both natural, unimproved (Nardus stricta, Agrostis capillaris, Festuca ovina and F. rubra) and fertilized, improved (Holcus lanatus, Lolium perenne and Trifolium repens) grasslands were either left unamended or treated with lime, nitrogen, or lime plus nitrogen in a 75-day glasshouse experiment. Lime and nitrogen amendment were shown to have a greater effect on microbial activity, biomass and bacterial ribotype number than plant species. Liming increased soil pH, microbial activity and biomass, while decreasing ribotype number. Nitrogen addition decreased soil pH, microbial activity and ribotype number. Addition of lime plus nitrogen had intermediate effects, which appeared to be driven more by lime than nitrogen. Terminal restriction fragment length polymorphism (TRFLP) analysis revealed that lime and nitrogen addition altered soil bacterial community structure, while plant species had little effect. These results were further confirmed by multivariate redundancy analysis, and suggest that soil lime and nitrogen status are more important controllers of bacterial community structure than plant rhizosphere effects.

  16. Metagenome and metatranscriptome data for Rifle CMT-03 laboratory microcosm experiment completed in April 2014

    DOE Data Explorer

    Jewell, Talia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Karaoz, Ulas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bill, Markus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chakraborty, Romy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brodie, Eoin L [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Williams, Kenneth Hurst [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beller, Harry R [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-04-01

    Sediment samples were collected during installation of monitoring borehole CMT-03. Microcosms were constructed and inoculated under anerobic conditions with these sediments and anaerobic Rifle artificial groundwater. Microcosm metagenomes and metatranscriptomes were sampled every 5 days for a period of 20 days. The dataset gives gene-level annotations, binning, metagenomic and metatranscriptomic coverages for these microcosms.

  17. 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.

  18. ANAEROBIC BIODEGRADATION OF ALKYLBENZENES IN LABORATORY MICROCOSMS REPRESENTING AMBIENT CONDITIONS

    EPA Science Inventory

    A microcosm study was performed to document the anaerobic biodegradation of benzene, toluene, ethylbenzene, m- xylene, and/or o-xylene in petroleum-contaminated aquifer sediment from sites in Michigan (MI) and North Carolina (NC) and relate the results to previous field investiga...

  19. 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...

  20. 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...

  1. What Is Aerobic Dancing?

    MedlinePlus

    ... aerobics can reach up to six times the force of gravity, which is transmitted to each of the 26 bones in the foot. Because of the many side-to-side motions, shoes need an arch design that will compensate ...

  2. Effects of chemical additives on hydrocarbon disappearance and biodegradation in freshwater marsh microcosms.

    PubMed

    Nyman, J A; Klerks, P L; Bhattacharyya, S

    2007-09-01

    We determined how a cleaner and a dispersant affected hydrocarbon biodegradation in wetland soils dominated by the plant Panicum hemitomon, which occurs throughout North and South America. Microcosms received no hydrocarbons, South Louisiana crude, or diesel; and no additive, a dispersant, or a cleaner. We determined the concentration of four total petroleum hydrocarbon (TPH) measures and 43 target hydrocarbons in water and sediment fractions 1, 7, 31, and 186 days later. Disappearance was distinguished from biodegradation via hopane-normalization. After 186 days, TPH disappearance ranged from 24% to 97%. There was poor correlation among the four TPH measures, which indicated that each quantified a different suite of hydrocarbons. Hydrocarbon disappearance and biodegradation were unaltered by these additives under worse-case scenarios. Any use of these additives must generate benefits that outweigh the lack of effect on biodegradation demonstrated in this report, and the increase in toxicity that we reported earlier.

  3. Hydrocarbon biodegradation kinetics in an intact unsaturated zone soil core

    SciTech Connect

    Moyer, E.E.; Ostendorf, D.W.; Richards, R.J.; Goodwin, S.

    1995-12-31

    Aerobic biodegradation of vapor-phase petroleum hydrocarbons was evaluated in an intact soil core from the site of an aviation gasoline release. A mid-depth unsaturated zone soil core was subjected to a flow of nitrogen gas, oxygen, water vapor, and vapor-phase hydrocarbons in a configuration analogous to a biofilter or an in situ bioventing or sparging situation. The vertical profiles of vapor-phase hydrocarbon concentration in the soil core were determined by gas chromatography of vapor samples. Steady-state concentrations were input to a simple analytical model balancing advection and first-order biodegradation of hydrocarbons. First-order rate constants for each major hydrocarbon compound were used to calibrate the model to the concentration profiles. Compounds with lower molecular weights, fewer methyl groups, and no quaternary carbons tended to have higher rate constants. The first-order rate constants were consistent with kinetic parameters determined from microcosm studies at the same field site, suggesting that both estimation methods were effective.

  4. Effects of Nitramine Explosive CL-20 on the Soil Microinvertebrate Community in a Sandy Loam Soil

    DTIC Science & Technology

    2013-09-01

    expand upon the ecotoxicological significance of data from standardized single-species toxicity tests. 15. SUBJECT TERMS Soil invertebrate community...14 3. Toxicity Benchmarks for Soil Invertebrates Established in Standardized Single-Species Toxicity Tests with...overestimate the potential exposure effects on soil invertebrates in the field. For example, in a 7 day microcosm assay, total microarthropod

  5. 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.

  6. Plant bioindicators for polycyclic aromatic hydrocarbon toxicity in aquatic microcosms

    SciTech Connect

    Gensemer, R.W.; Solomon, K.R.; Day, K.E.; Hodson, P.V.; Servos, M.R.; Greenberg, B.M.

    1994-12-31

    Plant bioindicators are being developed to assess the effects of polycyclic aromatic hydrocarbons (PAHs) in experimental aquatic ecosystems. The approach is to develop and test biomarker assays that are specifically predictive of ecological events at the population and/or community levels of organization in artificial aquatic microcosms. PAH mixtures were introduced into a series of aquatic microcosms using the wood preservative creosote as a PAH source. The authors applied creosote at five dosage levels designed to simulate conductions observed at highly contaminated sites. The growth and biomass of phytoplankton, periphyton, and macrophytes were then measured throughout the growing season, and compared to one or more biomarker assays used to detect PAH contamination. Preliminary results using fluorescence induction on aquatic macrophytes suggest that PAHs can significantly inhibit photosynthesis at even modest concentrations 1--4 hours after exposure. This assay thus is not only a sensitive indicator of PAH exposure, but may also describe mechanisms of PAH toxicity that ultimately reduce biomass or population growth for aquatic plants in these microcosms.

  7. 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)

  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.

  9. Implementation of Aerobic Programs.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD).

    This information is intended for health professionals interested in implementing aerobic exercise programs in public schools, institutions of higher learning, and business and industry workplaces. The papers are divided into three general sections. The introductory section presents a basis for adhering to a health fitness lifestyle, using…

  10. 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

  11. 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)

  12. Naphthenic acids and surrogate naphthenic acids in methanogenic microcosms.

    PubMed

    Holowenko, F M; Mackinnon, M D; Fedorak, P M

    2001-08-01

    Naphthenic acids (NAs) are a complex mixture of naturally occurring acyclic and cyclic aliphatic carboxylic acids in petroleum. In the Athabasca oil sands. NAs have been identified as the largest component of dissolved organic matter in the tailings waters from oils sands extraction processes. They are the major contributor to the acute toxicity of the fine tailings wastewaters at the oil sands extraction plants in northeastern Alberta, Canada. In this study, three sources of NAs were studied, including commercially available NAs, those extracted from oil sands process-affected waters, and individual naphthenic-like surrogate compounds. Analysis by gas chromatography-mass spectrometry demonstrated differences between the commercial and extracted NAs. The NAs derived from the process-affected waters showed a short-term inhibition of methanogenesis from H2 or acetate, but with time the populations resumed methane production. It has been postulated that microbial metabolism of the carboxylated side chains of NAs would lead to methane production. The two NA mixtures failed to stimulate methanogenesis in microcosms that contained either oil sands fine tailings or domestic sewage sludge. However, in microcosms with sewage sludge, methanogenesis was stimulated by some surrogate NAs including 3-cyclohexylpropanoic acid at 400-800 mg/L, 5-cyclohexylpentanoic acid at 200 mg/L or 6-phenylhexanoic acid at 200 and 400 mg/L. When added at 200 mg/L to methanogenic microcosms containing fine tailings, 3-cyclohexylpropanoic and 4-cyclohexylbutanoic acids produced methane yields that suggested mineralization of the side chain and the ring.

  13. Sulfur oxidation in rice field soil: activity, enumeration, isolation and characterization of thiosulfate-oxidizing bacteria.

    PubMed

    Stubner, S; Wind, T; Conrad, R

    1998-12-01

    In rice paddy fields the bulk soil is anoxic, but oxygenated zones occur in the surrounding of the rice roots to where oxygen is transported via the aerenchyma system of the rice plants. In the anaerobic soil compartments sulfate is consumed by sulfate-reducing bacteria. In the rhizosphere the reduced sulfur compounds can be reoxidized by sulfur-oxidizing bacteria. Measurements of the potential activity of thiosulfate-oxidizing bacteria in soil slurries derived from planted rice soil microcosms showed turnover rates of 2-6 mumol d-1 g-dw-1. Thiosulfate was oxidized to sulfate with tetrathionate as intermediate. Most probable number (MPN) enumeration with three aerobic media and one anaerobic nitrate-amended medium showed that thiosulfate-oxidizing bacteria were abundant in paddy soil and in rhizosphere soil at numbers of 10(5) to 10(6) per gram dry weight soil. Nine isolates of S-oxidizing bacteria were obtained from enrichment cultures or from the highest dilutions of the MPN series and were affiliated to four different phylogenetic groups. These isolates were characterized by physiological properties and by comparative 16S rDNA sequence analysis. Three isolates (TA1-AE1, TA1-A1 and TA12-21) were shown to be facultatively chemolithoautotrophic strains of Ancylobacter aquaticus. Three further isolates (Tv6-2b, Z2A-6A and Z4A-2A) were also facultatively chemolithoautotrophic and were affiliated with the Xanthobacter sp. group, probably representing new strains of X. flavus or X. tagetidis. Strain SZ-2111 was phylogenetically related to Bosea thiooxidans. However, the genus Bosea is described as obligately heterotrophic, whereas strain 5Z-2111 was able to grow autotrophically. The isolates 5Z-C1 and TBW3 were obligate chemolithoautotrophs and were closely affiliated with Thiobacillus thioparus. Our results showed that S-oxidizing bacteria were abundant and active in rice paddy soil and consisted of physiologically and phylogenetically diverse populations.

  14. 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.

  15. 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.

  16. Ecological changes in oral microcosm biofilm during maturation

    NASA Astrophysics Data System (ADS)

    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.

  17. 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.

  18. 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...

  19. Detection by denaturing gradient gel electrophoresis of ammonia-oxidizing bacteria in microcosms of crude oil-contaminated mangrove sediments.

    PubMed

    dos Santos, A C F; Marques, E L S; Gross, E; Souza, S S; Dias, J C T; Brendel, M; Rezende, R P

    2012-01-27

    Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.

  20. Aerobic biodegradation of selected monoterpenes.

    PubMed

    Misra, G; Pavlostathis, S G; Perdue, E M; Araujo, R

    1996-07-01

    Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C. Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested. All four hydrocarbons and two alcohols were readily degraded. The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization. The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter.

  1. Aerobic landfill bioreactor

    SciTech Connect

    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.

  2. Aerobic landfill bioreactor

    SciTech Connect

    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.

  3. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    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 F and 140 F in steady state.

  4. Starvation survival of Candida albicans in various water microcosms.

    PubMed

    Chaieb, Kamel; Kouidhi, Bochra; Zmantar, Tarek; Mahdouani, Kacem; Bakhrouf, Amina

    2011-08-01

    Candida is a major Human pathogen causing a variety of infections and can survive for extended period of time in aquatic environment including marine and fresh water. In this study we compared a colorimetric XTT assay to colony forming units (CFU) count to evaluate the survival potential of Candida albicans incubated in water microcosms. Our results showed that cells maintain cultivability within a long period followed by a decline in cultivability and a drop of plate counts to less than 20 cell ml(-1) after 150 days in tap water, 190 days in rain water and 200 days in seawater. In addition we noted that 10% of cells viability was reached after 150 days in seawater, 180 days in rain water and 210 days in tap water. Molecular method confirms the persistence of C. albicans cells in water during long time starvation period.

  5. Population dynamics of Vibrio spp. associated with marine sponge microcosms.

    PubMed

    Hoffmann, Maria; Fischer, Markus; Ottesen, Andrea; McCarthy, Peter J; Lopez, Jose V; Brown, Eric W; Monday, Steven R

    2010-12-01

    Vibrio is a diverse genus of marine-associated bacteria with at least 74 species and more expected as additional marine ecospheres are interrogated. This report describes a phylogenetic reconstruction of Vibrio isolates derived from one such unique ecosystem, marine sponges (Phylum Porifera) collected from depths of 150 to 1242 feet. 16S rRNA gene sequencing along with molecular typing of 16S-23S rRNA intergenic spacer regions clustered many sponge-associated Vibrio (spp) with current known species. That is, several benthic Vibrio species commensal with Porifera sponges seemed genetically linked to vibrios associated with coastal or shallow-water communities, signalling a panmictic population structure among seemingly ecologically disparate strains. Conversely, phylogenetic analysis provided evidence for at least two novel Vibrio speciation events within this specific sponge microcosm. Collectively, these findings earmark this still relatively unknown environment as a bastion of taxonomic and phylogenetic variability for the genus and probably other bacterial taxa.

  6. Habitat Complexity in Aquatic Microcosms Affects Processes Driven by Detritivores

    PubMed Central

    Flores, Lorea; Bailey, R. A.; Elosegi, Arturo; Larrañaga, Aitor; Reiss, Julia

    2016-01-01

    Habitat complexity can influence predation rates (e.g. by providing refuge) but other ecosystem processes and species interactions might also be modulated by the properties of habitat structure. Here, we focussed on how complexity of artificial habitat (plastic plants), in microcosms, influenced short-term processes driven by three aquatic detritivores. The effects of habitat complexity on leaf decomposition, production of fine organic matter and pH levels were explored by measuring complexity in three ways: 1. as the presence vs. absence of habitat structure; 2. as the amount of structure (3 or 4.5 g of plastic plants); and 3. as the spatial configuration of structures (measured as fractal dimension). The experiment also addressed potential interactions among the consumers by running all possible species combinations. In the experimental microcosms, habitat complexity influenced how species performed, especially when comparing structure present vs. structure absent. Treatments with structure showed higher fine particulate matter production and lower pH compared to treatments without structures and this was probably due to higher digestion and respiration when structures were present. When we explored the effects of the different complexity levels, we found that the amount of structure added explained more than the fractal dimension of the structures. We give a detailed overview of the experimental design, statistical models and R codes, because our statistical analysis can be applied to other study systems (and disciplines such as restoration ecology). We further make suggestions of how to optimise statistical power when artificially assembling, and analysing, ‘habitat complexity’ by not confounding complexity with the amount of structure added. In summary, this study highlights the importance of habitat complexity for energy flow and the maintenance of ecosystem processes in aquatic ecosystems. PMID:27802267

  7. Fate of pathogenic bacteria in microcosms mimicking human body sites.

    PubMed

    Castellani, Francesco; Ghidini, Valentina; Tafi, Maria Carla; Boaretti, Marzia; Lleo, Maria M

    2013-07-01

    During the infectious process, pathogens may reach anatomical sites where they are exposed to substances interfering with their growth. These substances can include molecules produced by the host, and his resident microbial population, as well as exogenous antibacterial drugs. Suboptimal concentrations of inhibitory molecules and stress conditions found in vivo (high or low temperatures, lack of oxygen, extreme pH) might induce in bacteria the activation of survival mechanisms blocking their division capability but allowing them to stay alive. These "dormant" bacteria can be reactivated in particular circumstances and would be able to express their virulence traits. In this study, it was evaluated the effect of some environmental conditions, such as optimal and suboptimal temperatures, direct light and antibiotic sub-inhibitory concentrations doses of antibiotic, on the human pathogens Escherichia coli and Enterococcus faecalis when incubated in fluids accumulated in the body of patients with different pathologies. It is shown that inoculation in a number of accumulated body fluids and the presence of gentamicin, reliable conditions encountered during pathological states, induce stress-responding strategies enabling bacteria to persist in microcosms mimicking the human body. Significant differences were detected in Gram-negative and Gram-positive species with E. faecalis surviving, as starved or viable but non-culturable forms, in any microcosm and condition tested and E. coli activating a viable but non-culturable state only in some clinical samples. The persistence of bacteria under these conditions, being non-culturable, might explain some recurrent infections without isolation of the causative agent after application of the standard microbiological methods.

  8. [Exploration of microcosmic Chinese medicine used by western medicine].

    PubMed

    Zheng, Zhi-jing

    2015-02-01

    "Microcosmic syndrome", "treatment based on syndrome differentiation", and "combination of disease identification and syndrome differentiation" generally refer to a mode: following the syndrome if with no disease identified, following the disease if with no syndrome type differentiated. For example, Chinese medical treatment of hypertension, high blood lipids, increased transaminase, and so on candirectly use Chinese recipes, but no longer with syndrome differentiation. Clinical application of Chinese patent medicine can also obtain favorable clinical. Western doctors need not follow syndrome differentiation. The invention of artemisinin was screened from more than 40 000 kinds of compounds and herbs, but with no reference of any traditional Chinese medical theory. A lot of folk remedy and empirical recipes have obtained effective efficacy but unnecessarily with profound Chinese medical theories. Various evidences showed that disease can also be cured without syndrome differentiation. I held that it might be associated with the same mechanism of Chinese medicine and Western medicine. Any disease can be cured or alleviated by Chinese medicine is a result from its modern pharmacological effect, which is achieved by improving etiologies, and pathogeneses. I was inspired by whether we can directly use traditional Chinese medicine with modern pharmacological effects to treat symptomatic disease. So I raised an idea of microcosmic Chinese medicine used by Western medicine, i.e., we find and use Chinese herbs with relatively effective modern pharmacological effect to treat diseases targeting at patients' clinical symptoms and signs, as well as various positive laboratory results (collectively called as microscopic dialectical indicators). More Western doctors would use it to treat disease due to omission of complicated and mysterious syndrome differentiation. This will promote extensive application and expansion of Chi- nese medicine and pharmacy, enlarge the team of

  9. Microcosm-based interaction studies between members of two ecophysiological groups of bioemulsifier producer and a hydrocarbon degrader from the Indian intertidal zone.

    PubMed

    Markande, A R; Nerurkar, A S

    2016-07-01

    Isolates were obtained from intertidal zone site samples from all five western and one eastern coastal states of India and were screened. These ecophysiological groups of aerobic, mesophilic, heterotrophic, sporulating, and bioemulsifier-producing bacteria were from Planococcaceae and Bacillaceae. This is the first report of bioemulsifier production by Sporosarcina spp., Lysinibacillus spp., B. thuringiensis, and B. flexus. In this group, Solibacillus silvestris AM1 was found to produce the highest emulsification activity (62.5 %EI) and the sample that yielded it was used to isolate the ecophysiological group of non-bioemulsifier-producing, hydrocarbon-degrading bacteria (belonging to Chromatiales and Bacillales). These yielded hitherto unreported degrader, Rheinheimera sp. CO6 which was selected for the interaction studies (in a microcosm) with bioemulsifier-producing S. silvestris AM1. The gas chromatographic study of these microcosm experiments revealed increased degradation of benzene, toluene, and xylene (BTX) and the growth of Rheinheimera sp. CO6 in the presence of bioemulsifier produced by S. silvestris AM1. Enhancement of the growth of S. silvestris AM1 in the presence of Rheinheimera sp. CO6 was observed possibly due to reduced toxicity of BTX suggesting mutualistic association between the two. This study elucidates the presence and interaction between enhancers and degraders in a hydrocarbon-contaminated intertidal zone and contributes to the knowledge during application of the two in remediation processes.

  10. Effects of drain-fill cycling on chlorpyrifos mineralization in wetland sediment-water microcosms.

    PubMed

    Gebremariam, Seyoum Yami; Beutel, Marc W

    2010-03-01

    Constructed treatment wetlands are efficient at retaining a range of pesticides, however the ultimate fate of many of these compound is not well understood. This study evaluated the effect of drain-fill cycling on the mineralization of chlorpyrifos, a commonly used organophosphate insecticide, in wetland sediment-water microcosms. Monitoring of the fate of (14)C ring-labeled chlorpyrifos showed that drain-fill cycling resulted in significantly lower mineralization rates relative to permanently flooded conditions. The reduction in mineralization was linked to enhanced partitioning of the pesticide to the sediment phase, which could potentially inhibit chlorpyrifos hydrolysis and mineralization. Over the nearly two-month experiment, less than 2.5% of the added compound was mineralized. While rates of mineralization in this experiment were higher than those reported for other soils and sediments, their low magnitude underscores how persistent chlorpyrifos and its metabolites are in aquatic environments, and suggests that management strategies and ecological risk assessment should focus more on ultimate mineralization rather than the simple disappearance of the parent compound.

  11. 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

  12. 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

  13. 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…

  14. 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.

  15. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation

    NASA Astrophysics Data System (ADS)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  16. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation.

    PubMed

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions

    PubMed Central

    Kato, Yoichiro; Okami, Midori

    2011-01-01

    Background and Aims Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. ‘Aerobic rice culture’ aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant–water relationships and stomatal conductance in aerobic culture. Methods Root system development, stomatal conductance (gs) and leaf water potential (Ψleaf) were monitored in a high-yielding rice cultivar (‘Takanari’) under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> –10 kPa) and mildly dry (> –30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; Kpa) was measured under flooded and aerobic conditions. Key Results Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72–85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower Kpa than plants grown under flooded conditions. Ψleaf was always significantly lower in aerobic culture than in flooded culture, while gs was unchanged when the soil moisture was at around field capacity. gs was inevitably reduced when the soil water potential at 20-cm depth reached –20 kPa. Conclusions Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψleaf. Ψleaf may reduce even if Kpa is not significantly changed, but the lower Ψleaf would certainly occur in case Kpa reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep

  4. 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.

  5. 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

  6. Ecological impact and environmental fate of perfluorooctane sulfonate on the zooplankton community in indoor microcosms.

    PubMed

    Sanderson, Hans; Boudreau, Timothy M; Mabury, Scott A; Cheong, Woo-Jay; Solomon, Keith R

    2002-07-01

    There is presently a substantial amount of information being gathered concerning the environmental risk associated with the perfluorooctane sulfonate (PFOS) compound. The U.S. Environmental Protection Agency (U.S. EPA) is requiring that more research be completed before making definitive decisions concerning the regulatory issues covered in the significant new use rule (18/10-2000) under the Toxic Substance Control Act. However, there are no risk assessment requirements under seminatural conditions in microcosms. The PFOS can enter, and has been found in, the aquatic environment through different pathways, including spills associated with use of fire-fighting foams containing PFOS, leaching from washing Scotchgard-treated clothes with the wastewater, leaching from various coatings, discharges as residual waste from fluorochemical production, or volatilization and transportation atmospherically. The biota is the sink of PFOS rather than the sediment or soil. The aim of this article is to determine a 35-d community no-observable-effect concentration (NOECcommunity) for freshwater zooplankton and the fate of PFOS during the course of study. The PFOS persisted in the water phase with only slight reductions over the study; only the decrease from 33.9 mg/L at day 1 to 29.8 mg/L at day 35 was significant. A 90 to 100% reduction (p < 0.01) of the total zooplankton population was found after one week of exposure to 30 mg PFOS/L and a similar reduction after two weeks at 10 mg PFOS/L. The Daphnia magna 21-d NOECsurvival of 12 mg/L has previously been found in a standard laboratory bioassay by 3M. The rank order of susceptibility for the test community was Copepoda > Cladocera > Rotifera, assuming all adverse direct effects.

  7. 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

  8. Bacterial community response to petroleum hydrocarbon amendments in freshwater, marine, and hypersaline water-containing microcosms.

    PubMed

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

    2013-10-01

    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.

  9. Responses of meiofauna and nematode communities to crude oil contamination in a laboratory microcosm experiment

    NASA Astrophysics Data System (ADS)

    Kang, Teawook; Oh, Je Hyeok; Hong, Jae-Sang; Kim, Dongsung

    2016-09-01

    We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The density of nematodes was similar to that of the total meiofauna. Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). However, SIMPROF analysis showed no significant difference between the two groups ( p > 0.05). Bolbolaimus spp. (37.1%) were dominant among the nematodes. Cluster analysis showed similar results for nematode and meiofaunal communities. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p < 0.05). Within the nematodes, epistrate feeders (group 2A: 46%) were the most abundant trophic group. Among the treatment groups, the abundance of group 2A increased in low-concentration microcosms and decreased in high-concentration microcosms. Thus, our findings provide information on the effects of oil pollution on meiofauna in the intertidal zones of sandy beaches.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. Toxicity of formulated glyphosate (glyphos) and cosmo-flux to larval and juvenile colombian frogs 2. Field and laboratory microcosm acute toxicity.

    PubMed

    Bernal, M H; Solomon, K R; Carrasquilla, G

    2009-01-01

    The spraying of coca (Erythroxylum coca) with glyphosate (coca mixture, a combination of formulated glyphosate, Glyphos, and an adjuvant, Cosmo-Flux) in Colombia has raised concerns about possible impacts on amphibians. Although acute LC50 for 8 species of Colombian frogs ranged from 1.2 to 2.78 mg acid equivalents (a.e.)/L, these exposures were conducted in the laboratory in the absence of sediments and organic matter such as would occur under realistic field conditions. In order to assess the effects of overspray of frog habitat under field conditions, Gosner stage 25 tadpoles of Rhinella granulosa, R. marina, Hypsiboas crepitans, and Scinax ruber were placed in outdoor microcosms made from polyethylene plastic fish ponds (2.07 m in diameter, 37 cm high) in an experimental area in Tolima, Colombia. The bottoms of the microcosms were covered with a 3-cm layer of local soil and they were filled to a depth of 15 cm (above the sediment) with local spring water. After up to 100 tadpoles of each frog species were placed in the microcosms, they were sprayed with the coca mixture at concentrations greater and less than the normal application rate (3.69 kg glyphosate a.e./ha). Mortality at 96 h in the control microcosms was between 0 and 16% and LC50 values were between 8.9 and 10.9 kg glyphosate a.e./ha (equivalent to initial concentrations of 5963 to 7303 microg glyphosate a.e./L). Mortality >LC50 was only observed in the tested species when the application rate was >2-fold the normal application rate. In other experiments, juvenile and adult terrestrial stages of frogs were exposed by direct spraying to a range of concentrations of coca mixture. Juveniles and adults were exposed in plastic food containers (19 x 19 cm). The bottom of the container was filled with moistened soil and leaf litter to a depth of 1 cm and 0.5 cm, respectively. Mortality in the controls was low, from 0 to 10%, and from 0 to 35% at the normal application rate. LC50 values ranged between 4.5 kg

  15. 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.

  16. 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.

  17. Die aerobe Glykolyse der Tumorzelle

    NASA Astrophysics Data System (ADS)

    Schneider, Friedhelm

    1981-01-01

    A high aerobic glycolysis (aerobic lactate production) is the most significant feature of the energy metabolism of rapidly growing tumor cells. Several mechanisms, which may be different in different cell lines, seem to be involved in this characteristic of energy metabolism of the tumor cell. Changes in the cell membrane leading to increased uptake and utilization of glucose, a high level of fetal types of isoenzymes, a decreased number of mitochondria and a reduced capacity to metabolize pyruvate are some factors which must be taken into consideration. It is not possible to favour one of them at the present time.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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)

  3. Surfactant Enhanced Microbial Degradation of JP-8 Contaminated Soil

    DTIC Science & Technology

    1996-12-01

    temperature on the respiration of soil microorganisms. Graph of the oxygen consumption rate of uncontaminated Kittyhawk silt soil. Small fluctuations in...Temperature result in increases or decreases in the respiration rate of the indigenous organisms present in the soil. Each observation (interval) represents...problem due to different respiration rates of replicate microcosms. Also, the experiment revealed that Novell II appeared to be inhibitory, since the

  4. The recovery of heat-stressed Escherichia coli in lake water microcosms.

    PubMed

    Lim, C H; Flint, K P

    1995-12-01

    Escherichia coli was heat stressed at 55 degrees, 60 degrees or 65 degrees C in sterile flasks of lake water. After 6 h at these temperatures the viable count on nutrient agar had dropped below the limits of detection (1 colony in 100 ml). The flasks were transferred to a 15 degrees C incubator and left for 7 d. Recovery of the stressed E. coli was shown to occur within 48 h at this temperature. Recovery also occurred in microcosms amended with 5% (v/v) synthetic sewage. The stressed E. coli multiplied in the amended but not in the unamended microcosms.

  5. 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

  6. Anaerobic Degradation of Pristane in Nitrate-Reducing Microcosms and Enrichment Cultures

    PubMed Central

    Bregnard, T. P.; Haner, A.; Hohener, P.; Zeyer, J.

    1997-01-01

    Microcosm studies were conducted under nitrate-reducing conditions with diesel fuel-contaminated aquifer material from a site treated by in situ bioremediation. In the microcosms, the consumption of nitrate and the production of inorganic carbon were strongly stimulated by the addition of the isoprenoid alkane pristane (2,6,10,14-tetramethylpentadecane). Within 102 days enrichment cultures degraded more than 90% of the pristane supplied as coatings on reticulated sinter glass rings. The study demonstrates that pristane can no longer be regarded as recalcitrant under anaerobic conditions. PMID:16535616

  7. 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.

  8. 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)

  9. 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

  10. Occurrence and persistence of indigenous transconjugants carrying conjugative plasmids in soil.

    PubMed

    Inoue, Daisuke; Soda, Satoshi; Tsutsui, Hirofumi; Yamazaki, Yuji; Murashige, Katsushi; Sei, Kazunari; Fujita, Masanori; Ike, Michihiko

    2009-09-01

    The transfer of the self-transmissible plasmids, RP4 and pJP4, from introduced bacteria to indigenous bacteria was examined in soil and slurry microcosms. The introduced plasmids persisted in indigenous transconjugants despite the low survival of introduced donors. The potential of the transconjugants for growth and conjugation affects the persistence of introduced plasmids in soil.

  11. The Rate of Permafrost Carbon Release Under Aerobic and Anaerobic Decomposition

    NASA Astrophysics Data System (ADS)

    Lee, H.; Vogel, J. G.; Schuur, E. A.; Inglett, K. S.

    2008-12-01

    One of the ecological consequences caused by increased temperature in northern ecosystems is permafrost thawing. When ice-rich permafrost thaws, the land surface may develop lakes but could also drain, depending on the soil ice content and topographic position. More than 50% of terrestrial soil carbon is stored in the permafrost region, which may be subjected to faster decomposition due to permafrost thaw. As a result of thaw effects on hydrology, soil organic matter from permafrost may be deposited in an oxic or an anoxic environment after permafrost thaw. We tested how the oxygen status and soil substrate quality affect CO2 and CH4 emissions from permafrost soil by conducting laboratory soil incubation experiment. We measured CO2 emissions from aerobic incubations, and CO2 and CH4 from anaerobic incubations. Soil C to N ratios and enzyme activities (glucosidase, phosphatase, and aminopeptidase) were also analyzed to compare the organic matter quality of permafrost soils from different sites. The mass of C lost after 108 days of aerobic soil incubation ranged 0.06-7.98 mg C gdw-1 for mineral soil layers and 2.21-18.56 mg C gdw-1 for organic soil layers. In the anaerobic incubations, C loss in the form of CO2 emissions was 0.04-4.87 mg C gdw-1 while CH4 emissions were 0.00-0.23 mg C gdw- 1. The total C loss was about 3 times lower for the anaerobic soil incubations compared to the aerobic incubations. The carbon loss from CO2 emissions in aerobic incubation showed a linear relationship with C:N (R2=0.58). Overall, rates of C loss were 4-57 times higher in organic soils than mineral soils, which indicated the importance of substrate quality in the decomposition of permafrost carbon. The initial soil enzyme activities were higher in organic soils as compared to mineral soils for all the enzymes tested. Aminopeptidase activity was linearly correlated with C to N ratio (R2=0.78) and both phosphatase and glucosidase were exponentially correlated with %C (R2

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

    PubMed

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

    2014-07-15

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

  13. The MBA in Singapore: A Microcosm of Communication Training for Management

    ERIC Educational Resources Information Center

    Rogers, Priscilla S.; Wong, Irene F. H.

    2005-01-01

    This study assesses communication training provided in MBA and executive MBA programs in Singapore. The authors found that Singapore is a microcosm in terms of (a) requirements for English competency, (b) the variety of communication offerings, and (c) the lack of uniformity in the delivery of communication training. Whereas Singaporean MBA/EMBA…

  14. 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.

  15. 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...

  16. Direct and indirect effects of pollutants on algae and algivorous ciliates in an aquatic indoor microcosm.

    PubMed

    Liebig, Markus; Schmidt, Gunnar; Bontje, Daniel; Kooi, Bob W; Streck, Georg; Traunspurger, Walter; Knacker, Thomas

    2008-06-23

    An aquatic indoor microcosm was used to study effects of the pesticides parathion-methyl and prometryn on phototrophic flagellates (Cryptomonas sp.) and predatory ciliates (Urotricha furcata). Parathion-methyl caused effects to flagellates and ciliates at the range of low mg L(-1), regardless of whether the organisms were exposed separately or combined in the multi-species test system. Prometryn caused effects on the flagellates at low microg L(-1) concentrations, resulting in a NOEC of 6.9 microg L(-1) in the single-species test and a NOEC of 15.2 microg L(-1) in the multi-species microcosm. For ciliates the NOEC decreased by factor 145 in the multi-species test compared to the NOEC of 2.2 mg L(-1) in the single-species test when exposed to prometryn. The lower NOEC for ciliates exposed to prometryn in the microcosm was most likely caused by an indirect effect due to reduced availability of flagellates as food. The measurement of nutrient concentrations in the test media and organisms facilitated the modelling of effects. The presented aquatic indoor microcosm is considered as a tool which could be standardised and applied as an instrument to provide data for higher tier risk assessment.

  17. 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...

  18. 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.

  19. 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…

  20. The influence of sediment resuspension on the degradation of phenanthrene in flow-through microcosms.

    PubMed

    LeBlanc, Lawrence A; Gulnick, Jeanne D; Brownawell, Bruce J; Taylor, Gordon T

    2006-03-01

    The effect of sediment resuspension on the mineralization of phenanthrene was examined in microcosms and sediment slurries. In computer-controlled, flow-through microcosms, 14C-phenanthrene-amended sediments were resuspended into overlying oxic water at frequencies of 12, 4, 1, 0.25 and 0 d(-1). In slurry bottle experiments 14C-phenanthrene-amended sediments were continuously resuspended under oxic (excess air headspace) and anoxic (N2 headspace) conditions and mineralization was measured at periods from 2 h to 7 days. Our main findings were: (1) mineralization rate constants from the microcosms ranged from 0.001 to 0.01 d(-1) and increased with frequency of resuspension, (2) these rates fell between those measured in oxic and anoxic slurries and were predicted within a factor of 2.5 by a model in which mineralization depended on the degree of oxygen exposure, and (3) the phenanthrene-degrading bacterial community was more active in resuspended sediments incubated in the microcosms than in sediments which were not resuspended, or which were stored under refrigeration. We conclude from these experiments that the effects of sediment resuspension on phenanthrene degradation are consistent with a primary role of average oxygen exposure, and also an alteration in the PAH-degrading activity of microbial populations.

  1. 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...

  2. 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...

  3. Persistence and renaturation efficiency of thermally treated waste recombinant DNA in defined aquatic microcosms.

    PubMed

    Fu, Xiao H; Wang, Lei; Le, Yi Q; Hu, Jia J

    2012-01-01

    To validate the possibility of horizontal gene transfer (HGT) from thermally denatured recombinant DNA discharged into the eco-system, a constructed plasmid was used to investigate the persistence and renaturation efficiency of thermally denatured recombinant DNA in defined aquatic microcosms. The results revealed that there was undecayed recombinant plasmid pMDLKJ material being discharged into the aquatic microcosms even after thermal treatment at either 100°C (using boiling water) or at 120°C (using an autoclave). The plasmid had a relatively long persistence time. At least 10(2) copies μL(-1) of a specific 245 bp fragment of the plasmid could be detected after 12 h and a specific 628 bp fragment could be detected up to 2 h. The thermally denatured recombinant DNA could efficiently renature and recover its functional double stranded structure in aquatic microcosms and the highest concentration of double-stranded DNA (dsDNA) occurred around 1 h after the thermally denatured DNA was added to the system. These results imply that when thermally treated recombinant DNAs are discharged into aquatic environments, they have enough time to renature and possibly transfer to other organisms. In addition, the recombinant DNA added to aquatic microcosms could be absorbed by the seston particles in water, such as mineral, organic and colloids particles with a maximum absorption value of about 5.18 ng L(-1). This absorbed DNA could persist longer in aquatic environments than free recombinant DNA, thus further favoring HGT.

  4. Exposure of Sink Drain Microcosms to Triclosan: Population Dynamics and Antimicrobial Susceptibility

    PubMed Central

    McBain, Andrew J.; Bartolo, Robert G.; Catrenich, Carl E.; Charbonneau, Duane; Ledder, Ruth G.; Price, Bradford B.; Gilbert, Peter

    2003-01-01

    Recent concern that the increased use of triclosan (TCS) in consumer products may contribute to the emergence of antibiotic resistance has led us to examine the effects of TCS dosing on domestic-drain biofilm microcosms. TCS-containing domestic detergent (TCSD) markedly lowered biofouling at 50% (wt/vol) but was poorly effective at use levels. Long-term microcosms were established and stabilized for 6 months before one was subjected to successive 3-month exposures to TCSD at sublethal concentrations (0.2 and 0.4% [wt/vol]). Culturable bacteria were identified by 16S rDNA sequence analysis, and their susceptibilities to four biocides and six antibiotics were determined. Microcosms harbored ca. 10 log10 CFU/g of biofilm, representing at least 27 species, mainly gamma proteobacteria, and maintained dynamic stability. Viable cell counts were largely unaffected by TCSD exposure, but species diversity was decreased, as corroborated by denaturing gradient gel electrophoresis analysis. TCS susceptibilities ranged widely within bacterial groups, and TCS-tolerant strains (including aeromonads, pseudomonads, stenotrophomonads, and Alcaligenes spp.) were isolated before and after TCSD exposure. Several TCS-tolerant bacteria related to Achromobacter xylosoxidans became clonally expanded during dosing. TCSD addition did not significantly affect the community profiles of susceptibility to the test biocides or antibiotics. Several microcosm isolates, as well as reference bacteria, caused clearing of particulate TCS in solid media. Incubations of consortia and isolates with particulate TCS in liquid led to putative TCS degradation by the consortia and TCS solubilization by the reference strains. Our results support the view that low-level exposure of environmental microcosms to TCS does not affect antimicrobial susceptibility and that TCS is degradable by common domestic biofilms. PMID:12957932

  5. Calcium precipitate induced aerobic granulation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules.

  6. 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.

  7. 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.

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

    DOE PAGES

    Xu, Xiaofeng; Elias, Dwayne A.; Graham, David 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

  9. WWOX loss activates aerobic glycolysis.

    PubMed

    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.

  10. 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

  11. Low C/N ratio raw textile wastewater reduced labile C and enhanced organic-inorganic N and enzymatic activities in a semiarid alkaline soil.

    PubMed

    Roohi, Mahnaz; Riaz, Muhammad; Arif, Muhammad Saleem; Shahzad, Sher Muhammad; Yasmeen, Tahira; Ashraf, Muhammad Arslan; Riaz, Muhammad Atif; Mian, Ishaq A

    2017-02-01

    Application of raw and treated wastewater for irrigation is an extensive practice for agricultural production in arid and semiarid regions. Raw textile wastewater has been used for cultivation in urban and peri-urban areas in Pakistan without any systematic consideration to soil quality. We conducted a laboratory incubation study to investigate the effects of low C/N ratio raw textile wastewater on soil nitrogen (N) contents, labile carbon (C) as water-soluble C (WSC) contents, and activities of urease and dehydrogenase enzymes. The 60-day incubation study used an alkaline clay loam aridisol that received 0 (distilled water), 25, 50, and 100% wastewater concentrations, and microcosms were incubated aerobically under room temperature at 70% water holding capacity. Results revealed that raw wastewater significantly (p < 0.05) changed soil N pools and processes, WSC contents, and enzymatic activities. The organic and inorganic N species increased with increasing wastewater concentrations, whereas WSC contents followed an opposite trend. The highest NH4(+)-N and NO3(-)-N contents were observed in soil treated with 100% wastewater. The extractable organic N (EON) contents always represented >50% of the soil total Kjeldahl N (TKN) contents and served as the major N pool. However, nitrification index (NO3(-)-N/NH4(+)-N ratio) decreased at high wastewater concentrations. A significant negative correlation was observed between EON and WSC (p < 0.05) and between net nitrification and WSC/EON ratio (p < 0.01). In contrast, nitrification index and WSC contents were correlated, positively suggesting WSC potentially controlling N turnover in nutrient-poor aridisol. We found significant (p < 0.0001) positive correlations of soil urease and dehydrogenase enzymatic activities with soil-extractable mineral N contents indicating coupled N cycling and soil biological activity. Higher production and accumulation of soil NO3(-)-N and EON contents in concentrated wastewater

  12. Aerobic Metabolism of Streptococcus agalactiae

    PubMed Central

    Mickelson, M. N.

    1967-01-01

    Streptococcus agalactiae cultures possess an aerobic pathway for glucose oxidation that is strongly inhibited by cyanide. The products of glucose oxidation by aerobically grown cells of S. agalactiae 50 are lactic and acetic acids, acetylmethylcarbinol, and carbon dioxide. Glucose degradation products by aerobically grown cells, as percentage of glucose carbon, were 52 to 61% lactic acid, 20 to 23% acetic acid, 5.5 to 6.5% acetylmethylcarbinol, and 14 to 16% carbon dioxide. There was no evidence for a pentose cycle or a tricarboxylic acid cycle. Crude cell-free extracts of S. agalactiae 50 possessed a strong reduced nicotinamide adenine dinucleotide (NADH2) oxidase that is also cyanide-sensitive. Dialysis or ultrafiltration of the crude, cell-free extract resulted in loss of NADH2 oxidase activity. Oxidase activity was restored to the inactive extract by addition of the ultrafiltrate or by addition of menadione or K3Fe(CN)6. Noncytochrome iron-containing pigments were present in cell-free extracts of S. agalactiae. The possible participation of these pigments in the respiration of S. agalactiae is presently being studied. PMID:4291090

  13. Terrestrial Microcosm Evaluation of Two Army Smoke-Producing Compounds.

    DTIC Science & Technology

    1988-01-29

    way ANCV, and linear regression tc test :-e rate of decline of C02-C soil respiration over time (b-parameter in tne selected model for each cart...surface area, x is the ieosition of phosphorus level), was fitted to the data. When the qudcratic terTm was rot sigrificant (p > 0.35), a linear model , y...sweetclover), and ele’ent P I’ , s, and 7b ta’e ,, :lants. ?ce-,-es cnse c, e . ,e,e L these effects data using either a quadratic or linear model

  14. Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

    PubMed

    Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

    2017-03-06

    Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat.

  15. 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...

  16. Enhanced biodegradation of total polycyclic aromatic hydrocarbons (TPAHs) by marine halotolerant Achromobacter xylosoxidans using Triton X-100 and β-cyclodextrin--a microcosm approach.

    PubMed

    Dave, Bharti P; Ghevariya, Chirag M; Bhatt, Jwalant K; Dudhagara, Dushyant R; Rajpara, Rahul K

    2014-02-15

    Ability of Achromobacter xylosoxidans, a chrysene degrading marine halotolerant bacterium to degrade polycyclic aromatic hydrocarbons (PAHs) using a cost effective laboratory microcosm approach, was investigated. Effect of variables as chrysene, glucose as a co-substrate, Triton X-100 as a non-ionic surfactant and β-cyclodextrin as a PAHs solubilizer was examined on degradation of low molecular weight (LMW) and high molecular weight (HMW) PAHs. A total of eleven PAHs detected from polluted saline soil were found to be degraded. Glucose, in combination with Triton X-100 and β-cyclodextrin resulted in 2.8 and 1.4-fold increase in degradation of LMW PAHs and 7.59 and 2.23-fold increase in degradation of HMW PAHs, respectively. Enhanced biodegradation of total PAHs (TPAHs) by amendments with Triton X-100 and β-cyclodextrin using Achromobacter xylosoxidans can prove to be promising approach for in situ bioremediation of marine sites contaminated with PAHs.

  17. Identification of soil bacteria able to degrade phenanthrene bound to a hydrophobic sorbent in situ.

    PubMed

    Regonne, Raïssa Kom; Martin, Florence; Mbawala, Augustin; Ngassoum, Martin Benoît; Jouanneau, Yves

    2013-09-01

    Efficient bioremediation of PAH-contaminated sites is limited by the hydrophobic character and poor bioavailability of pollutants. In this study, stable isotope probing (SIP) was implemented to track bacteria that can degrade PAHs adsorbed on hydrophobic sorbents. Temperate and tropical soils were incubated with (13)C-labeled phenanthrene, supplied by spiking or coated onto membranes. Phenanthrene mineralization was faster in microcosms with PAH-coated membranes than in microcosms containing spiked soil. Upon incubation with temperate soil, phenanthrene degraders found in the biofilms that formed on coated membranes were mainly identified as Sphingomonadaceae and Actinobacteria. In the tropical soil, uncultured Rhodocyclaceae dominated degraders bound to membranes. Accordingly, ring-hydroxylating dioxygenase sequences recovered from this soil matched PAH-specific dioxygenase genes recently found in Rhodocyclaceae. Hence, our SIP approach allowed the detection of novel degraders, mostly uncultured, which differ from those detected after soil spiking, but might play a key role in the bioremediation of PAH-polluted soils.

  18. 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

  19. Fate and effects of the insecticide-miticide chlorfenapyr in outdoor aquatic microcosms.

    PubMed

    Rand, Gary M

    2004-05-01

    The concentrations of chlorfenapyr in water and sediment in a lentic pond following early and late applications in a Florida crop treatment program were predicted using PRZM and EXAMS modeling and incorporating 30 years of actual rainfall data. An outdoor microcosm study was also conducted to determine the fate of chlorfenapyr and its effects on zooplankton, macroinvertebrates, phytoplankton, and fish in a freshwater system under exposure conditions representing simulated surface runoff and/or spray drift. The microcosm design used a regression model with five treatments (i.e., 300 microg/L spray, 30 microg/L spray, 15 microg/L spray and 30 microg/L runoff, 1.2 microg/L spray and 2.5 microg/L runoff, 30 microg/L runoff) plus a control. Chlorfenapyr was applied as an aqueous suspension concentrate (36% a.i.) to six microcosm tanks (30.9 m3). The no-observed-effect-concentration (NOEC) for zooplankton was the water concentration produced from the combination 1.2 microg/L spray and 2.5 microg/L runoff treatment. The NOEC for bluegill sunfish was the water concentration produced from the 30 microg/L runoff, which was significantly higher than the exposure concentrations from the lowest combination treatment. Chlorfenapyr was more toxic via spray to the water than via an exposure simulating surface runoff. The 96-h time weighted average concentrations (TWAs) from the lowest joint treatment and the 30 microg/L runoff treatment in the microcosm study were similar to model-predicted water 96-h TWA concentrations from early and late applications. The toxicity data from laboratory and microcosm studies along with water exposure data indicate low hazard to zooplankton species in the water column. Although chlorfenapyr remained in sediment, TWAs concentrations from the microcosm study along with model-predicted concentrations indicate low hazard to benthic invertebrate species based on acute toxicity to amphipods in the laboratory. Results from this assessment indicate that

  20. Response of zooplankton and phytoplankton communities to creosote-impregnated Douglas fir pilings in freshwater microcosms.

    PubMed

    Sibley, P K; Harris, M L; Bestari, K T; Steele, T A; Robinson, R D; Gensemer, R W; Day, K E; Solomon, K R

    2004-07-01

    Creosote has been used extensively as an industrial wood preservative for the protection of marine pilings, railway ties, and utility poles and is a common source of polycyclic aromatic hydrocarbons (PAHs) into aquatic environments. At present, there is little information by which to judge the potential for creosote leached from impregnated pilings to cause toxicity to biota in aquatic environments. The objective of the current study was to assess the effects of creosote on zooplankton and phytoplankton populations in freshwater microcosms in relation to changes in the concentration and composition of PAHs leached from creosote-impregnated Douglas fir pilings during an 83-day exposure period. The study consisted of single microcosms containing one half, one, two, three, four, and six treated pilings. Two microcosms that received untreated pilings were used as controls. The total surface area of pilings in each microcosm was normalized by adding the appropriate number of untreated pilings. Samples were collected periodically between -14 and 83 days pre- and postexposure to determine aqueous concentrations of 15 priority PAHs and to assess the response of zooplankton and phytoplankton communities. Plankton community response to creosote was analyzed using principle responses curves. Peak aqueous concentrations of sigmaPAH occurred at day 7, ranging from 7.3 to 97.3 microg/L. Zooplankton abundance decreased in all microcosms after introduction of the impregnated pilings, with the magnitude of response varying as a function of aqueous creosote concentration. Using inverse regression, a no-observed-effect concentration for the zooplankton community of 11.1 microg/L was estimated. In contrast, algal abundance and diversity increased in all treatments between 7 and 21 days and attained levels up to twice that in control microcosms. This trend most likely reflected decreased grazing pressure because of the decrease in zooplankton populations, but it may also have reflected

  1. Soil chromatographic movement of technetium-99 through selected Minnesota soils

    SciTech Connect

    Balogh, J.C.; Grigal, D.F.

    1980-11-01

    We monitored the movement of technetium-99 through 41 samples of Minnesota soils, using soil column layer chromatography (CLC), a modification of soil thin layer chromatography. Under the aerobic conditions of soil CLC, /sup 99/Tc occurs as the pertechnetate anion. Pertechnetate movement in the soils was characterized by the traditional R/sub f/ chromatographic parameter. Reduced R/sub f/ values were statistically related to elevated levels of soil organic matter. Complexation of /sup 99/Tc, related to soil organic matter, was weak. Elution patterns of /sup 99/Tc in the soil CLC columns were asymmetric, with pertechnetate retardation associated with both hydrodynamic dispersion and weak retention. Pertechnetate was less mobile than was Cl/sup -/ in selected soils by soil CLC.

  2. Lower limb loading in step aerobic dance.

    PubMed

    Wu, H-W; Hsieh, H-M; Chang, Y-W; Wang, L-H

    2012-11-01

    Participation in aerobic dance is associated with a number of lower extremity injuries, and abnormal joint loading seems to be a factor in these. However, information on joint loading is limited. The purpose of this study was to investigate the kinetics of the lower extremity in step aerobic dance and to compare the differences of high-impact and low-impact step aerobic dance in 4 aerobic movements (mambo, kick, L step and leg curl). 18 subjects were recruited for this study. High-impact aerobic dance requires a significantly greater range of motion, joint force and joint moment than low-impact step aerobic dance. The peak joint forces and moments in high-impact step aerobic dance were found to be 1.4 times higher than in low-impact step aerobic dance. Understanding the nature of joint loading may help choreographers develop dance combinations that are less injury-prone. Furthermore, increased knowledge about joint loading may be helpful in lowering the risk of injuries in aerobic dance instructors and students.

  3. Redox-induced mobilization of copper, selenium, and zinc in deltaic soils originating from Mississippi (U.S.A.) and Nile (Egypt) River Deltas: A better understanding of biogeochemical processes for safe environmental management.

    PubMed

    Shaheen, Sabry M; Frohne, Tina; White, John R; DeLaune, Ron D; Rinklebe, Jörg

    2017-01-15

    Studies about the mobilization of potentially toxic elements (PTEs) in deltaic soils can be challenging, provide critical information on assessing the potential risk and fate of these elements and for sustainable management of these soils. The impact of redox potential (EH), pH, iron (Fe), manganese (Mn), sulfate (SO4(2-)), chloride (Cl(-)), aliphatic dissolved organic carbon (DOC), and aromatic dissolved organic carbon (DAC) on the mobilization of copper (Cu), selenium (Se), and zinc (Zn) was studied in two soils collected from the Nile and Mississippi Rivers deltaic plains focused on increasing our understanding of the fate of these toxic elements. Soils were exposed to a range of redox conditions stepwise from reducing to oxidizing soil conditions using an automated biogeochemical microcosm apparatus. Concentrations of DOC and Fe were high under reducing conditions as compared to oxidizing conditions in both soils. The proportion of DAC in relation to DOC in solution (aromaticity) was high in the Nile Delta soil (NDS) and low in the Mississippi Delta soil (MDS) under oxidizing conditions. Mobilization of Cu was low under reducing conditions in both soils which was likely caused by sulfide precipitation and as a result of reduction of Cu(2+) to Cu(1+). Mobilization of Se was high under low EH in both soils. Release of Se was positively correlated with DOC, Fe, Mn, and SO4(2-) in the NDS, and with Fe in the MDS. Mobilization of Zn showed negative correlations with EH and pH in the NDS while these correlations were non-significant in the MDS. The release dynamics of dissolved Zn could be governed mainly by the chemistry of Fe and Mn in the NDS and by the chemistry of Mn in the MDS. Our findings suggest that a release of Se and Zn occurs under anaerobic conditions, while aerobic conditions favor the release of Cu in both soils. In conclusion, the release of Cu, Se, and Zn under different reducing and oxidizing conditions in deltaic wetland soils should be taken into

  4. Monitoring operational and leachate characteristics of an aerobic simulated landfill bioreactor.

    PubMed

    Giannis, A; Makripodis, G; Simantiraki, F; Somara, M; Gidarakos, E

    2008-01-01

    Long-term biodegradation of MSW in an aerobic landfill bioreactor was monitored as a function of time during 510 days of operation. Operational characteristics such as air importation, temperature and leachate recirculation were monitored. The oxygen utilization rates and biodegradation of organic matter rates showed that aerobic biodegradation was feasible and appropriate to proceed in aerobic landfill bioreactor. Leachate analyses showed that the aerobic bioreactor could remove above 90% of chemical oxygen demand (COD) and close to 100% of biochemical oxygen demand (BOD5) from leachate. Ammonium (NH4+), nitrate (NO3-) and sulphate (SO4(2-)) concentrations of leachate samples were regularly measured. Results suggest that nitrification and denitrification occurred simultaneously, and the increase in nitrate did not reach the levels predicted stoichiometrically, suggesting that other processes were occurring. Leachate recirculation reduced the concentrations of heavy metals because of the effect of the high pH of the leachate, causing heavy metals to be retained by processes such as sorption on MSW, carbonate precipitation, and hydroxide precipitation. Furthermore, the compost derived from the aerobic biodegradation of the organic matter of MSW may be considered as soil improvement in the agricultural plant production. Bio-essays indicated that the ecotoxicity of leachate from the aerobic bioreactor was not toxic at the end of the experiment. Finally, after 510 days of degradation, waste settlement reached 26% mainly due to the compost of the organic matter.

  5. 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

  6. Microbial community dynamics associated with veterinary antibiotics removal in constructed wetlands microcosms.

    PubMed

    Fernandes, Joana P; Almeida, C Marisa R; Pereira, Ana C; Ribeiro, Iolanda L; Reis, Izabela; Carvalho, Pedro; Basto, M Clara P; Mucha, Ana P

    2015-04-01

    This study aimed to evaluate the response of the microbial community from CWs microcosms tested for the removal of two veterinary antibiotics, enrofloxacin (ENR) and tetracycline (TET), from livestock industry wastewater. Three treatments were tested (control, ENR or TET (100 μg L(-1))) over 12 weeks in microcosms unplanted and planted with Phragmites australis. CWs removal efficiency was relatively stable along time, with removals higher than 98% for ENR and 94% for TET. In addition, CWs were able to reduce wastewater toxicity, independently of antibiotics presence. Despite no significant differences were observed in terms of microbial abundance, bacterial richness or diversity, analysis of similarities (two-way crossed ANOSIM) showed a significant effect of both time and treatments in bacterial community structure. This study points to CWs applicability for veterinary antibiotics removal from livestock wastewaters, showing that CWs microbial communities were able to adapt without significant changes in their diversity or depuration capacity.

  7. 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

  8. Direct and indirect effects of the fungicide azoxystrobin in outdoor brackish water microcosms.

    PubMed

    Gustafsson, Kerstin; Blidberg, Eva; Elfgren, Irene Karlsson; Hellström, Anna; Kylin, Henrik; Gorokhova, Elena

    2010-02-01

    The effects of the strobilurin fungicide azoxystrobin were studied in brackish water microcosms, with natural plankton communities and sediment. Two experiments were conducted: Experiment 1 (nominal conc. 0, 15 and 60 microg/L, 24-L outdoor microcosms for 21 days) and a second, follow-up, Experiment 2 (nominal conc. 0, 3, 7.5, 15 microg/L, 4-L indoor microcosms for 12 days). The microcosms represent a simplified brackish water community found in shallow semi-enclosed coastal areas in agricultural districts in the Baltic Sea region. Measured water concentrations of the fungicide (Experiment 1) were, on average, 83 and 62% of nominal concentrations directly after application, and 25 and 30% after 21 days, for the low and high dose treatments, respectively, corresponding to mean DT50-values of 15.1 and 25.8 days, for low and high dose treatments, respectively. In Experiment 1, direct toxic effects on calanoid copepods at both test concentrations were observed. Similarly, in Experiment 2, the copepod abundance was significantly reduced at all tested concentrations. There were also significant secondary effects on zooplankton and phytoplankton community structure, standing stocks and primary production. Very few ecotoxicological studies have investigated effects of plant protection products on Baltic organisms in general and effects on community structure and function specifically. Our results show that azoxystrobin is toxic to brackish water copepods at considerably lower concentrations than previously reported from single species tests on freshwater crustaceans, and that direct toxic effects on this ecologically important group may lead to cascade effects altering lower food webs and ecosystem functioning.

  9. 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.

  10. Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

    USGS Publications Warehouse

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

    2001-01-01

    Mineralization of [U-14C] methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

  11. Naturally-Derived Microcosms for Estimating Stress Effects in Aquatic Ecosystems

    DTIC Science & Technology

    1991-05-31

    responses and the responses of standard test species. However, a heavy ash basin considered non -toxic to daphnids and fish adversely affected microcosms...artificial substrates to examine stress responses of biological systems using non -taxonomic measures cf adverse effect based on energy flow ’production...mobile laboratory test systems. To ensure that existing work in developing automated data collection and non -taxonomic methods for evaluating system

  12. 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.

  13. Integrated Anaerobic-Aerobic Biodegradation of Multiple Contaminants Including Chlorinated Ethylenes, Benzene, Toluene, and Dichloromethane.

    PubMed

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

    Complete bioremediation of soils containing multiple volatile organic compounds (VOCs) remains a challenge. To explore the possibility of complete bioremediation through integrated anaerobic-aerobic biodegradation, laboratory feasibility tests followed by alternate anaerobic-aerobic and aerobic-anaerobic biodegradation tests were performed. Chlorinated ethylenes, including tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC), and dichloromethane (DCM) were used for anaerobic biodegradation, whereas benzene, toluene, and DCM were used for aerobic biodegradation tests. Microbial communities involved in the biodegradation tests were analyzed to characterize the major bacteria that may contribute to biodegradation. The results demonstrated that integrated anaerobic-aerobic biodegradation was capable of completely degrading the seven VOCs with initial concentration of each VOC less than 30 mg/L. Benzene and toluene were degraded within 8 days, and DCM was degraded within 20 to 27 days under aerobic conditions when initial oxygen concentrations in the headspaces of test bottles were set to 5.3% and 21.0%. Dehalococcoides sp., generally considered sensitive to oxygen, survived aerobic conditions for 28 days and was activated during the subsequent anaerobic biodegradation. However, degradation of cis-DCE was suppressed after oxygen exposure for more than 201 days, suggesting the loss of viability of Dehalococcoides sp., as they are the only known anaerobic bacteria that can completely biodegrade chlorinated ethylenes to ethylene. Anaerobic degradation of DCM following previous aerobic degradation was complete, and yet-unknown microbes may be involved in the process. The findings may provide a scientific and practical basis for the complete bioremediation of multiple contaminants in situ and a subject for further exploration.

  14. U(VI) bioreduction with emulsified vegetable oil as the electron donor--microcosm tests and model development.

    PubMed

    Tang, Guoping; Wu, Wei-Min; Watson, David B; Parker, Jack C; Schadt, Christopher W; Shi, Xiaoqing; Brooks, Scott C

    2013-04-02

    We conducted microcosm tests and biogeochemical modeling to study U(VI) reduction in contaminated sediments amended with emulsified vegetable oil (EVO). Indigenous microorganisms in the sediments degraded EVO and stimulated Fe(III), U(VI), and sulfate reduction, and methanogenesis. Acetate concentration peaked in 100-120 days in the EVO microcosms versus 10-20 days in the oleate microcosms, suggesting that triglyceride hydrolysis was a rate-limiting step in EVO degradation and subsequent reactions. Acetate persisted 50 days longer in oleate- and EVO- than in ethanol-amended microcosms, indicating that acetate-utilizing methanogenesis was slower in the oleate and EVO than ethanol microcosms. We developed a comprehensive biogeochemical model to couple EVO hydrolysis, production, and oxidation of long-chain fatty acids (LCFA), glycerol, acetate, and hydrogen, reduction of Fe(III), U(VI) and sulfate, and methanogenesis with growth and decay of multiple functional microbial groups. By estimating EVO, LCFA, and glycerol degradation rate coefficients, and introducing a 100 day lag time for acetoclastic methanogenesis for oleate and EVO microcosms, the model approximately matched observed sulfate, U(VI), and acetate concentrations. Our results confirmed that EVO could stimulate U(VI) bioreduction in sediments and the slow EVO hydrolysis and acetate-utilizing methanogens growth could contribute to longer term bioreduction than simple substrates (e.g., ethanol, acetate, etc.) in the subsurface.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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.

  20. Biosorbent, a promising material for remediation of eutrophic environments: studies in microcosm.

    PubMed

    Pantano, Glaucia; Ferreira, Josilei S; Aquino, Francisco W B; Pereira-Filho, Edenir R; Mozeto, Antonio A; Fadini, Pedro S

    2017-01-01

    Eutrophication is considered a global environmental problem that causes economic and biodiversity loss. Together with excess phosphorus in some aquatic environments, there is the depletion of phosphate rock deposits, which can directly affect fertilizer production and therefore global food security. Thus, the present work aimed to study a new remediation technique for eutrophic environments that enables the recovery of these environments through phosphorus adsorption in sawdust, creating the possibility to apply the phosphorus-enriched material as an agricultural fertilizer. The study was conducted in 36 microcosm flasks with water and sediment samples from a eutrophic reservoir in Ibirité/MG. The experiment was carried out using 18 control flasks and 18 others as treatment, consisting of water and eutrophic environment sediment and, additionally, two bags, containing 10 g of sawdust in each bag. The phosphorus adsorption on sawdust was more intense after 49 days of immersion in the microcosm, and reductions of 90% in the concentration of reactive soluble phosphorus were observed in the water column of the microcosm treatment at 159 days of the experiment. Based on the results, it can be concluded that, although the phosphorus concentration adsorbed on sawdust (16.2 μg g(-1)) is considered low, the use of the biosorbent is a particularly promising technique for remediation of eutrophic environments, as well as the possible reuse of the adsorbed phosphorus as a fertilizer in agriculture.

  1. [The impact of macro- and microcosm on the perception of illness and patient].

    PubMed

    Kalemba, Z

    1998-01-01

    The orgins of the idea of macro- and microcosm date back to the Ancient Greek thought. And however often that idea recurred in historically different epochs always carrying the sign of time it invariably assumed there was a correspondence between the universe (macrocosm) and man (microcosm). This type of correlation of both worlds was viewed as a reflection of cosmic harmony and common material (6/5th century BC) or the unity of what is created with the emphasis put on the uniqueness of man (Middle Ages). The philosophical consequence of such approach was the belief that the knowledge of one reality allows one to explain another. Most often such reasoning led from understanding the macrocosm (allowing for stars) to reflections on man. Advocates of such an approach to the perception of man and nature were two great scientific doctors Hippocrates (5th century BC) and Paracelsus (16th century). They both claimed that man retained communication with the whole universe. Paracelsus perceived the world and man in a unity that permitted to recognize an equivalent of anatomy in astronomy. This exceptional link between both cosms was a guarantee for health. Illness occurred as a result of the disturbance of harmony between both worlds. In this context, the task of medical science was to consist in such understanding of the forces present in macro- and microcosm that could restore the line between the nature and man inflicted with illness.

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

    DOE PAGES

    Sun, Jing; Chillrud, Steven N.; Mailloux, Brian J.; ...

    2015-10-23

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. In this paper, 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 bymore » 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. Finally, these results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers.« less

  3. 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

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

    SciTech Connect

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

    2015-10-23

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. In this paper, 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. Finally, these results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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…

  11. 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…

  12. Soil bioventing demonstration project

    SciTech Connect

    Cho, J.S.; Kampbell, D.H.; Wilson, J.T.; DiGiulio, D.C.

    1990-01-01

    A pilot scale demonstration project of a soil bioventing system, which utilizes the biodegradation in soil and physical removal of VOC by induced air flow, is in operation at the U.S. Coast Guard Aviation Field in Traverse City, Michigan. The system is being tested to determine its suitability for remediation of the vadose zone in conjunction with aquifer remediation at a site contaminated by an aviation gas spill. Several microcosm studies with soil obtained from the vertical profile of the contaminated site showed rapid microbial decompositions of hydrocarbon fumes with NPK nutrient and moisture addition. Basic removal kinetics data were obtained from these experiments. Field pneumatic pump tests for soil-air characterization have been conducted. The soil-air permeability and pressure distributions under the air injection/withdrawal systems were obtained. On the basis of information from the laboratory and field tests, a conceptual design at a field scale was made. The system will be implemented on the selected study site and the operation will start in fall, 1990. Additional soil core samplings and continuous monitoring of operation are planned.

  13. Structural dynamics of microbial communities in polycyclic aromatic hydrocarbon-contaminated tropical estuarine sediments undergoing simulated aerobic biotreatment.

    PubMed

    Obi, Chioma C; Adebusoye, Sunday A; Amund, Olukayode O; Ugoji, Esther O; Ilori, Mathew O; Hedman, Curtis J; Hickey, William J

    2017-02-11

    Coastal sediments contaminated by polycyclic aromatic hydrocarbons (PAHs) can be candidates for remediation via an approach like land farming. Land farming converts naturally anaerobic sediments to aerobic environments, and the response of microbial communities, in terms of community structure alterations and corresponding effects on biodegradative activities, is unknown. A key goal of this study was to determine if different sediments exhibited common patterns in microbial community responses that might serve as indicators of PAH biodegradation. Sediments from three stations in the Lagos Lagoon (Nigeria) were used in microcosms, which were spiked with a mixture of four PAH, then examined for PAH biodegradation and for shifts in microbial community structure by analysis of diversity in PAH degradation genes and Illumina sequencing of 16S rRNA genes. PAH biodegradation was similar in all sediments, yet each exhibited unique microbiological responses and there were no microbial indicators of PAH bioremediation common to all sediments.

  14. 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

  15. 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.

  16. 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.

  17. Aerobic fitness testing: an update.

    PubMed

    Stevens, N; Sykes, K

    1996-12-01

    This study confirms that all three tests are reliable tools for the assessment of cardiorespiratory fitness and the prediction of aerobic capacity. While this particular study consisted of active, youthful subjects, subsequent studies at University College Chester have found similar findings with larger databases and a wider cross-section of subjects. The Astrand cycle test and Chester step test are submaximal tests with error margins of 5-15 per cent and therefore, not as precise as maximal testing. However, they still give a reasonably accurate reflection of an individual's fitness without the cost, time, effort and risk on the part of the subject. The bleep test is a low-cost maximal test designed for well-motivated, active individuals who are used to running to physical exhaustion. Used on other groups, results will not accurately reflect cardiorespiratory fitness values. While all three tests have inherent advantages and disadvantages, perhaps the most important factors are the knowledge and skills of the tester. Without a sound understanding of the physiological principles underlying these tests, and the ability to conduct an accurate assessment and evaluation of results in a knowledgeable and meaningful way, then the credibility of the tests and the results become suspect. However, used correctly, aerobic capacity tests can provide valuable baseline data about the fitness levels of individuals and data from which exercise programmes may be developed. The tests also enable fitness improvements to be monitored, help to motivate participants by establishing reasonable and achievable goals, assist in risk stratification and facilitate participants' education about the importance of physical fitness for work and for life. Since this study was completed, further tests have been repeated on 140 subjects of a wider age and ability range. This large database confirms the results found in this study.

  18. Aerobic glycolysis and lymphocyte transformation

    PubMed Central

    Hume, David A.; Radik, Judith L.; Ferber, Ernst; Weidemann, Maurice J.

    1978-01-01

    1. The role of enhanced aerobic glycolysis in the transformation of rat thymocytes by concanavalin A has been investigated. Concanavalin A addition doubled [U-14C]glucose uptake by rat thymocytes over 3h and caused an equivalent increased incorporation into protein, lipids and RNA. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused a specific increase in pyruvate oxidation, leading to an increase in the percentage contribution of glucose to the respiratory fuel. 2. Acetoacetate metabolism, which was not affected by concanavalin A, strongly suppressed pyruvate oxidation in the presence of [U-14C]glucose, but did not prevent the concanavalin A-induced stimulation of this process. Glucose uptake was not affected by acetoacetate in the presence or absence of concanavalin A, but in each case acetoacetate increased the percentage of glucose uptake accounted for by lactate production. 3. [3H]Thymidine incorporation into DNA in concanavalin A-treated thymocyte cultures was sensitive to the glucose concentration in the medium in a biphasic manner. Very low concentrations of glucose (25μm) stimulated DNA synthesis half-maximally, but maximum [3H]thymidine incorporation was observed only when the glucose concentration was raised to 1mm. Lactate addition did not alter the sensitivity of [3H]-thymidine uptake to glucose, but inosine blocked the effect of added glucose and strongly inhibited DNA synthesis. 4. It is suggested that the major function of enhanced aerobic glycolysis in transforming lymphocytes is to maintain higher steady-state amounts of glycolytic intermediates to act as precursors for macromolecule synthesis. PMID:310305

  19. 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.

  20. Microbial Removal of Atmospheric Carbon Tetrachloride in Bulk Aerobic Soils▿

    PubMed Central

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

    2011-01-01

    Atmospheric concentrations of carbon tetrachloride (CCl4) were removed by bulk aerobic soils from tropical, subtropical, and boreal environments. Removal was observed in all tested soil types, indicating that the process was widespread. The flux measured in field chamber experiments was 0.24 ± 0.10 nmol CCl4 (m2 day)−1 (average ± standard deviation [SD]; n = 282). Removal of CCl4 and removal of methane (CH4) were compared to explore whether the two processes were linked. Removal of both gases was halted in laboratory samples that were autoclaved, dry heated, or incubated in the presence of mercuric chloride (HgCl2). In marl soils, treatment with antibiotics such as tetracycline and streptomycin caused partial inhibition of CCl4 (50%) and CH4 (76%) removal, but removal was not affected in soils treated with nystatin or myxothiazol. These data indicated that bacteria contributed to the soil removal of CCl4 and that microeukaryotes may not have played a significant role. Amendments of methanol, acetate, and succinate to soil samples enhanced CCl4 removal by 59%, 293%, and 72%, respectively. Additions of a variety of inhibitors and substrates indicated that nitrification, methanogenesis, or biological reduction of nitrate, nitrous oxide, or sulfate (e.g., occurring in possible anoxic microzones) did not play a significant role in the removal of CCl4. Methyl fluoride inhibited removal of CH4 but not CCl4, indicating that CH4 and CCl4 removals were not directly linked. Furthermore, CCl4 removal was not affected in soils amended with copper sulfate or methane, supporting the results with MeF and suggesting that the observed CCl4 removal was not significantly mediated by methanotrophs. PMID:21724884

  1. 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

    2012-06-05

    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.

  2. 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.

  3. CO2 and CH4 Production in Low-Temperature Soil Incubations from Low and High Centered Polygons, Barrow, Alaska, 2012-2013

    SciTech Connect

    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.

  4. CO2 and CH4 Production and CH4 Oxidation in Low Temperature Soil Incubations from Flat- and High-Centered Polygons, Barrow, Alaska, 2012

    SciTech Connect

    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.

  5. 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

  6. Transgenic strain Escherichia coli Z905/pPHL7 survival in aquatic microcosms with different salinity

    NASA Astrophysics Data System (ADS)

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

    The population dynamics and expression variability of transgenic microorganism (TM) Escherichia coli Z905/pPHL7 (AprLux+) bioluminescence genes cloned in recombinant plasmid have been studied in the artificial aquatic ecosystems with different salinity and bacterial species composition. It was shown that in competition with indigenous microflora the TM population was 2-4 times lower than in sterile fresh-water and brackish microcosms. Higher salt concentration in the medium led to the differencies in displaying plasmid genes expression as compared to fresh-water microcosms, independent of their complexity. Particularly, in brackish medium the bioluminescence expression reduced to a greater extent and was revealed only at plating into TM accumulative cultures with high content of selective factor (50-200 μ kg/ml ampicillin). TM clones isolated from fresh-water microcosms maintained higher bioluminescence level, at that for sterile microcosms it was higher than for non-sterile. Many clones could be seen during the plating of microcosm water samples on the selective media.

  7. Donor-dependent extent of uranium reduction for bioremediation of contaminated sediment microcosms.

    PubMed

    Madden, Andrew S; Palumbo, Anthony V; Ravel, Bruce; Vishnivetskaya, Tatiana A; Phelps, Tommy J; Schadt, Christopher W; 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 micromol L(-1) d(-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.

  8. Tracking the Response of Burkholderia cepacia G4 5223-PR1 in Aquifer Microcosms.

    PubMed

    Winkler, J; Timmis, K N; Snyder, R A

    1995-02-01

    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.

  9. 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.

  10. 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.

  11. Zostera marina seed burial can be enhanced by Manila clam Ruditapes philippinarum: A microcosm study

    NASA Astrophysics Data System (ADS)

    Li, Chang-Jun; Li, Wen-Tao; Liu, Jianying; Zhang, Xiumei; Zhang, Peidong

    2017-03-01

    Seagrass seed bank plays a key role in the regeneration of new vegetation when seagrasses are removed by the natural or man-made disaster. Various factors may affect the development of sediment seed bank. We conducted a microcosm experiment to test the effects of burrowing and feeding activities of Manila clam, Ruditapes philippinarum on the burial of Zostera marina seeds in sediments. The effects of lasting time (3-hour, 1-day, 3-day, 7-day, 14-day and 28-day), clam density (0, 2, 4 and 8 clams with shell length of 3 cm in each microcosm) and clam size (shell length of 2, 3 and 4 cm at 4-clam density) on seed burial were examined in plastic microcosm cores (30 cm high × 10 in inner diameter) in a 28-day period. Results showed that the seed burial depth significantly increased with time, the density and the size of clams. No seeds were buried in the sediment in the cores without clams during the whole experiment period. For the 3-cm clams, about 91.61% of the seeds were buried in the sediment at the end of the experiment in the high-density treatment (8 clams at each core); while in the medium and low-density treatments (4 and 2 clams in each core, respectively), about 76.93% and 60.61% of the seeds were buried in the sediment, respectively. For the size treatments, large (4 cm) clams buried 89.56% of the seeds at the end of the experiment, much more than those of medium (3 cm, 76.93%) and small (2 cm, 61.50%) size clams. During the whole experiment period, nearly all of the buried seeds were at a depth of from 0 cm to 5 cm. These results suggested that Manila clam Ruditapes philippinarum may play an important positive role in seagrass seed bank dynamics in the field.

  12. Plasmid Introduction in Metal-Stressed, Subsurface-Derived Microcosms: Plasmid Fate and Community Response

    PubMed Central

    Smets, Barth F.; Morrow, Jayne B.; Arango Pinedo, Catalina

    2003-01-01

    The nonconjugal IncQ plasmids pMOL187 and pMOL222, which contain the metal resistance-encoding genes czc and ncc, were introduced by using Escherichia coli as a transitory delivery strain into microcosms containing subsurface-derived parent materials. The microcosms were semicontinuously dosed with an artificial groundwater to set a low-carbon flux and a target metal stress (0, 10, 100, and 1,000 μM CdCl2), permitting long-term community monitoring. The broad-host-range IncPα plasmid RP4 was also transitorily introduced into a subset of microcosms. No novel community phenotype was detected after plasmid delivery, due to the high background resistances to Cd and Ni. At fixed Cd doses, however, small but consistent increases in Cdr or Nir density were measured due to the introduction of a single pMOL plasmid, and this effect was enhanced by the joint introduction of RP4; the effects were most significant at the highest Cd doses. The pMOL plasmids introduced could, however, be monitored via czc- and ncc-targeted infinite-dilution PCR (ID-PCR) methods, because these genes were absent from the indigenous community: long-term presence of czc (after 14 or 27 weeks) was contingent on the joint introduction of RP4, although RP4 cointroduction was not yet required to ensure retention of ncc after 8 weeks. Plasmids isolated from Nir transconjugants further confirmed the presence and retention of a pMOL222-sized plasmid. ID-PCR targeting the RP4-specific trafA gene revealed retention of RP4 for at least 8 weeks. Our findings confirm plasmid transfer and long-term retention in low-carbon-flux, metal-stressed subsurface communities but indicate that the subsurface community examined has limited mobilization potential for the IncQ plasmids employed. PMID:12839785

  13. Dissimilatory Iron Reduction and Odor Indicator Abatement by Biofilm Communities in Swine Manure Microcosms

    PubMed Central

    Castillo-Gonzalez, Hugo A.; Bruns, Mary Ann

    2005-01-01

    Animal waste odors arising from products of anaerobic microbial metabolism create community relations problems for livestock producers. We investigated a novel approach to swine waste odor reduction: the addition of FeCl3, a commonly used coagulant in municipal wastewater treatment, to stimulate degradation of odorous compounds by dissimilatory iron-reducing bacteria (DIRB). Two hypotheses were tested: (i) FeCl3 is an effective source of redox-active ferric iron (Fe3+) for dissimilatory reduction by bacteria indigenous to swine manure, and (ii) dissimilatory iron reduction results in significant degradation of odorous compounds within 7 days. Our results demonstrated that Fe3+ from FeCl3 was reduced biologically as well as chemically in laboratory microcosms prepared with prefiltered swine manure slurry and limestone gravel, which provided pH buffering and a substrate for microbial biofilm development. Addition of a 1-g liter−1 equivalent concentration of Fe3+ from FeCl3, but not from presynthesized ferrihydrite, caused initial, rapid solids flocculation, chemical Fe3+ reduction, and Eh increase, followed by a 2-day lag period. Between 2 and 6 days of incubation, increases in Fe2+ concentrations were accompanied by significant reductions in concentrations of volatile fatty acids used as odor indicators. Increases in Fe2+ concentrations between 2 and 6 days did not occur in FeCl3-treated microcosms that were sterilized by gamma irradiation or amended with NaN3, a respiratory inhibitor. DNA sequences obtained from rRNA gene amplicons of bacterial communities in FeCl3-treated microcosms were closely related to Desulfitobacterium spp., which are known representatives of DIRB. Use of iron respiration to abate wastewater odors warrants further investigation. PMID:16151075

  14. Combining rapid bioassessment and field-based microcosms for identifying impacts in an urban river.

    PubMed

    O'Brien, Matthew L; Pettigrove, Vincent; Carew, Melissa E; Hoffmann, Ary A

    2010-08-01

    Rapid bioassessment indices based on macroinvertebrates are the most commonly used tools for assessing stream condition. However, once stream degradation has been detected, it is often difficult to identify which environmental stressors are most important because of changes in multiple correlated factors. In this study, we examined eight sites in an urban river watershed using a field-based microcosm experiment and the rapid bioassessment-based biotic index, SIGNAL. The experiment assessed the effects of polluted river sediment by examining the macroinvertebrate taxa that colonized sediments at an unpolluted wetland. Results were compared with an assessment of field-collected macroinvertebrates using SIGNAL, a biotic index that assigns pollution sensitivity scores to macroinvertebrate families, and environmental data, to determine whether sediment pollution or other factors such as habitat deterioration were likely to be influencing riverine macroinvertebrate communities. The microcosm results indicated that common species (Tanytarsus fuscithorax, Procladius paludicola, and Ablabesmyia notabilis) and the overall macroinvertebrate assemblage did not significantly change among sediments from different sites, with the exception of local effects on a few uncommon taxa (Chironomus pseudoppositus, Kiefferulus martini, Cladotanytarsus australomancus, Chaoboridae, Polypedilum "S1," and Tanytarsus belairensis). In contrast, SIGNAL showed a gradual trend of deterioration from upstream to downstream, decreasing from a score of 6.5 in upstream areas (unimpacted) to a score of 4.4 in the downstream sites (moderately impacted). This result combined with a significant correlation of SIGNAL scores to habitat data suggested that habitat deterioration rather than polluted sediment was likely to be responsible for the declining stream condition detected with the rapid bioassessment approach. The addition of the microcosms to other monitoring approaches could be useful for determining

  15. 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.

  16. 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.

  17. Alkaline phosphatase activity of Escherichia coli starved in sterile lake water microcosms.

    PubMed

    Ozkanca, R; Flint, K P

    1996-03-01

    Escherichia coli grown in high or low phosphate medium was inoculated into a lake water starvation medium. The viable count decreased at 37 degrees C but not at the lower temperatures over 70 d. Alkaline phosphatase was monitored using a colorimetric assay with pNPP as the substrate. Derepression of the enzyme occurred in cultures starved for > 30 d in the lake water and within 5 d in lake water microcosms supplemented with carbon and nitrogen sources where there was rarely an increase in viable count. Chloramphenicol prevented the synthesis of alkaline phosphatase suggesting that, even under starvation conditions, de novo synthesis of the enzyme occurs.

  18. Evaluation of Graphite for Environmental Toxicity Using the Standard Aquatic Microcosm

    DTIC Science & Technology

    1988-08-01

    suspended as possible. The exposure concentrations were set so that a no effect and an effect level could be expected as estimated by Daphnia magna 48-hr...development. 2 ,3,4,5#6 During the last 3 years, we participated in the Food and Drug Administration (FDA) supported round-robin evaluation of the method...F.B., and Read, P.L., Standardized Aauatic Microcosm Protocol, Contract No. 223-80-2352, Vol I1, Food and Drug Administration, Washington, DC, 1983. 9

  19. Comparison of the effects of two herbicides and an insecticide on tropical freshwater plankton in microcosms.

    PubMed

    Leboulanger, C; Bouvy, M; Carré, C; Cecchi, P; Amalric, L; Bouchez, A; Pagano, M; Sarazin, G

    2011-11-01

    Natural plankton communities from a tropical freshwater reservoir (Combani Reservoir, Mayotte Island, Mozambique Channel) were exposed, in 20-l nutrient-enriched microcosms, to two nominal concentrations of three pesticides: the herbicides diuron (2.2 and 11 μg/l) and paraquat (10 and 40.5 μg/l) and the insecticide fenitrothion (10 and 100 μg/l), commonly used in the tropics for agriculture and disease vector control. Bacterioplankton, phytoplankton, and zooplankton communities were monitored for 5 days after exposure, and the concentrations of toxicant and major nutrients were measured. Bacterioplankton growth was noticeable in all systems and was slightly affected by pesticide at any concentration. A transitory increase in thymidine-based bacterial production was observed in diuron- and fenitrothion-treated microcosms, followed by a marked decrease in all microcosms after 5 days. The functional diversity of bacterioplankton, evaluated using BIOLOG ECO(®) microplates, was reduced by exposure to the highest pesticide concentrations. Phytoplankton was affected by pesticides in different ways. Chlorophyll biomass and biovolumes were increased by diuron addition and decreased by paraquat, whereas fenitrothion-treated microcosms remained unaffected relative to controls. Phytoplankton taxonomic diversity was decreased by paraquat and high doses of fenitrothion but was unaffected by addition of diuron. The decrease in diversity was due to a reduction in the number of species, whereas the density of small cells increased, especially after addition of paraquat. Heterotrophic flagellates were sensitive to paraquat and to the highest diuron concentration; a reduction in biomass of up to 90% was observed for 40.5 μg/l paraquat. Zooplankton, dominated by Thermocyclops decipiens and Diaphanosoma excisum, was slightly sensitive to diuron, and very sensitive to paraquat. High concentrations of the insecticide fenitrothion were effective only on young stages. The potential

  20. The effects of aerobic training on children's creativity, self-perception, and aerobic power.

    PubMed

    Herman-Tofler, L R; Tuckman, B W

    1998-10-01

    The article examines whether participation in an aerobic exercise program (AE), as compared with a traditional physical education class (PE), significantly increased children's perceived athletic competence, physical appearance, social acceptance, behavioral conduct, and global self-worth; increased their figural creativity; and improved aerobic power as measured by an 800-meter run around a track. Further research on the effects of different types of AE is discussed, as well as the need for aerobic conditioning in the elementary school.

  1. 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.

  2. Remediation of phenanthrene-contaminated soil by simultaneous persulfate chemical oxidation and biodegradation processes.

    PubMed

    Mora, Verónica C; Madueño, Laura; Peluffo, Marina; Rosso, Janina A; Del Panno, María T; Morelli, Irma S

    2014-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kgDRY SOIL of phenanthrene were treated with different persulfate (PS) concentrations 0.86-41.7 g/kgDRY SOIL and incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.

  3. 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.

  4. 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)

  5. The rise of oxygen and aerobic biochemistry.

    PubMed

    Saito, Mak A

    2012-01-11

    Analysis of conserved protein folding domains across extant genomes by Kim et al. in this issue of Structure provides insights into the timing of some of the earliest aerobic metabolisms to arise on Earth.

  6. 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

  7. 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)

  8. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    DTIC Science & Technology

    2014-10-27

    distribution is unlimited. Surface Structure of Aerobically Oxidized Diamond Nanocrystals The views, opinions and/or findings contained in this report...2211 diamond nanocrystals, REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8. PERFORMING...Room 254, Mail Code 8725 New York, NY 10027 -7922 ABSTRACT Surface Structure of Aerobically Oxidized Diamond Nanocrystals Report Title We investigate

  9. Aerobic catabolism of bile acids.

    PubMed Central

    Leppik, R A; Park, R J; Smith, M G

    1982-01-01

    Seventy-eight stable cultures obtained by enrichment on media containing ox bile or a single bile acid were able to utilize one or more bile acids, as well as components of ox bile, as primary carbon sources for growth. All isolates were obligate aerobes, and most (70) were typical (48) or atypical (22) Pseudomonas strains, the remainder (8) being gram-positive actinomycetes. Of six Pseudomonas isolates selected for further study, five produced predominantly acidic catabolites after growth on glycocholic acid, but the sixth, Pseudomonas sp. ATCC 31752, accumulated as the principal product a neutral steroid catabolite. Optimum growth of Pseudomonas sp. ATCC 31752 on ox bile occurred at pH 7 to 8 and from 25 to 30 degrees C. No additional nutrients were required to sustain good growth, but growth was stimulated by the addition of ammonium sulfate and yeast extract. Good growth was obtained with a bile solids content of 40 g/liter in shaken flasks. A near-theoretical yield of neutral steroid catabolites, comprising a major (greater than 50%) and three minor products, was obtained from fermentor growth of ATCC 31752 in 6.7 g of ox bile solids per liter. The possible commercial exploitation of these findings to produce steroid drug intermediates for the pharmaceutical industry is discussed. PMID:7149711

  10. Survival, Biofilm Formation, and Growth Potential of Environmental and Enteric Escherichia coli Strains in Drinking Water Microcosms

    PubMed Central

    Abberton, Cathy L.; Bereschenko, Ludmila; van der Wielen, Paul W. J. J.

    2016-01-01

    ABSTRACT Escherichia coli is the most commonly used indicator for fecal contamination in drinking water distribution systems (WDS). The assumption is that E. coli bacteria are of enteric origin and cannot persist for long outside their host and therefore act as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water, specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric isolates and one soil isolate) in sterile and nonsterile drinking water microcosms at 8 and 17°C, with T90 (time taken for a reduction in cell number of 1 log10 unit) values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (reverse transcription-)quantitative PCR [(RT-)Q-PCR] assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dynes [dyn] cm−2; BioFlux system; Fluxion); however, cell numbers did not increase when drinking water flowed over the biofilm (P > 0.05 by t test). Finally, E. coli regrowth within drinking water microcosms containing polyethylene PE-100 pipe wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli. The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely. IMPORTANCE The provision of clean, safe drinking water is fundamental to society. WDS deliver water to consumers via a vast network of pipes. E. coli is used as an indicator organism for recent contamination events based on the premise that it cannot survive for long outside its host. A key

  11. 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.

  12. Light structures phototroph, bacterial and fungal communities at the soil surface.

    PubMed

    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.

  13. 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

  14. Analysis of the life cycle of the soil saprophyte Bacillus cereus in liquid soil extract and in soil.

    PubMed

    Vilain, Sébastien; Luo, Yun; Hildreth, Michael B; Brözel, Volker S

    2006-07-01

    Bacillus is commonly isolated from soils, with organisms of Bacillus cereus sensu lato being prevalent. Knowledge of the ecology of B. cereus and other Bacillus species in soil is far from complete. While the older literature favors a model of growth on soil-associated organic matter, the current paradigm is that B. cereus sensu lato germinates and grows in association with animals or plants, resulting in either symbiotic or pathogenic interactions. An in terra approach to study soil-associated bacteria is described, using filter-sterilized soil-extracted soluble organic matter (SESOM) and artificial soil microcosms (ASM) saturated with SESOM. B. cereus ATCC 14579 displayed a life cycle, with the ability to germinate, grow, and subsequently sporulate in both the liquid SESOM extract and in ASM inserted into wells in agar medium. Cells grew in liquid SESOM without separating, forming multicellular structures that coalesced to form clumps and encasing the ensuing spores in an extracellular matrix. Bacillus was able to translocate from the point of inoculation through soil microcosms as shown by the emergence of outgrowths on the surrounding agar surface. Microscopic inspection revealed bundles of parallel chains inside the soil. The motility inhibitor L-ethionine failed to suppress outgrowth, ruling out translocation by a flagellar-mediated mechanism such as swimming or swarming. Bacillus subtilis subsp. subtilis Marburg and four Bacillus isolates taken at random from soils also displayed a life cycle in SESOM and ASM and were all able to translocate through ASM, even in presence of L-ethionine. These data indicate that B. cereus is a saprophytic bacterium that is able to grow in soil and furthermore that it is adapted to translocate by employing a multicellular mode of growth.

  15. 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.

  16. [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.

  17. A comparison of zooplankton sampling methods in evaluating copper sulfate toxicity in outdoor microcosms

    SciTech Connect

    Hellenbrandt, S.; La Point, T.W.; Shaw, J.L.; Marshall, S.J.; Ratte, H.T.

    1994-12-31

    Six outdoor microcosms (2m{sup 3}) were used to determine copper sulfate effects on epibenthic and planktonic zooplankton community structure. Microcosms were treated three times with CuSO{sub 4} at 0, 50, 100, 200, 350, 550 {mu}g Cu/L, respectively. Zooplankton was sampled biweekly from July through October 1993. Epibenthic zooplankton was collected with an inverted funnel trap, whereas planktonic zooplankton was sampled with an integrated water column sampler. Samples were sieved through a 35 {mu}m mesh and organisms preserved with 1% Lugol`s solution and later identified to genus or species level. Both communities initially decreased in total abundance at high copper rates. However, recovery started shortly after the final Cu application. Species richness was lowest at high copper concentrations, particularly in the epi-benthic community. Epibenthic zooplankton diversity decreased at high copper rates, whereas planktonic zooplankton diversity did not. Epi-benthic zooplankton may be a sensitive indicator of chemical stress and therefore be used to assess the bioavailability of sediment-bound xenobiotics.

  18. Understanding the controllability of complex networks from the microcosmic to the macrocosmic

    NASA Astrophysics Data System (ADS)

    Sun, Peng Gang; Ma, Xiaoke

    2017-01-01

    From a microcosmic perspective, nodes as meta-structures (or ‘smallest units’) for the constitution of a graph are of great importance for understanding complex network-based systems. In this paper, we develop a new framework, which first of all defines the meta-structures of a graph in different levels and tries to depict a graph from a low to a high level of abstraction. Further, based on this framework we study the meta-structure-driven control model and try to understand the controllability of complex networks from a microcosmic to a macrocosmic perspective. Finally, we analyze the impact of the community strength of networks on meta-structure-driven control. The results for artificial networks and real-world networks indicate that for meta-structure-driven control, the number of driver nodes is dependent on the networks’ degree distribution, and the dependence weakens as the level of the meta-structures increases. In addition, the networks are easier to control as the community strength increases, while this monotonicity is not preserved as the level of the meta-structures increases. We also find that it is harder to control sparse and inhomogeneous networks as the level of the meta-structures increases.

  19. Effects of two lubricant oils on marine nematode assemblages in a laboratory microcosm experiment.

    PubMed

    Beyrem, H; Louati, H; Essid, N; Aïssa, P; Mahmoudi, E

    2010-05-01

    The effects of two lubricating oils on nematode assemblages of a Tunisian lagoon were investigated in a microcosm experiment. Sediment from a pristine site in Ghar El Melh lagoon (Western Mediterranean) was treated with either mineral oil (Mobil 20 W-50), a synthetic lubricant (Mobil 0 W-40), the same two lubricants after use in a vehicle, and effects were examined after 5 weeks. Univariate analysis showed significant differences between most univariate indices of the nematode assemblages in all the lubricant treatments as compared to the control. Total nematode abundance (I), species richness (d) and number of species (S) decreased significantly in all lubricant contaminated microcosms. However, evenness was not affected in all treated replicates except in used mineral lubricant treatment where it was significantly higher than in the control. Diversity (H') was only altered in synthetic lubricant treatments. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the two lubricants treatments were varied: Daptonema trabeculosum was eliminated in all lubricant treatments and seemed to be an intolerant species to oil contamination. Spirinia gerlachi increased in mineral lubricant treatments ("clean" and used) but was eliminated in all synthetic lubricant treatments. This species could be categorized as "resistant" to mineral oil contamination and intolerant to synthetic lubricant contamination. Terschellingia longicaudata increased only in synthetic lubricant treatments ("clean" and used) and appeared to be a "synthetic oil-resistant" species.

  20. Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

    PubMed

    Tao, Wendong; Han, Jianqiu; Li, Hanyan

    2015-11-01

    Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained.

  1. 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.

  2. Microbial culture dynamics and chromium (VI) removal in packed-column microcosm reactors.

    PubMed

    Molokwane, Pulane E; Nkhalambayausi-Chirwa, Evans M

    2009-01-01

    Microbial Cr(VI) reduction in groundwater aquifer media was investigated in microcosm reactors extracted from Cr(VI) contaminated sites in South Africa. The reactors were operated under an influent Cr(VI) concentration of 40 mg/L to simulate the current Cr(VI) level at the contaminated site. Near complete Cr(VI) removal was observed in microcosm reactors inoculated with Cr(VI) reducing bacteria from dried activated sludge collected from a treatment plant receiving periodic loadings of Cr(VI). The best performance was observed under low hydraulic loading (flow rate, Q=0.310 cm(3)/hr). Microbial culture characterisation results showed a change in culture composition after 17 days of reactor operation, indicating Bacillus and Lysinibacillus species as the most dominant organisms in reactors that reduced Cr(VI). The predominance of Bacillus and Lysinibacillus species was either due to resilience against toxicity or adaptation to the changing conditions in the reactor. This research was the initial step towards the development of an in situ bioremediation process to contain the spread of a Cr(VI) plume in a groundwater aquifer at contaminated site in Brits, South Africa. South Africa holds about 72% percent of the world's chromium resources, the majority of which is mined in the North Eastern region of the country formally known as Transvaal.

  3. 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

  4. 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

  5. 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

  6. 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…

  7. Effect of long term anaerobic and intermittent anaerobic/aerobic starvation on aerobic granules.

    PubMed

    Pijuan, Maite; Werner, Ursula; Yuan, Zhiguo

    2009-08-01

    The effect of long term anaerobic and intermittent anaerobic/aerobic starvation on the structure and activity of aerobic granules was studied. Aerobic granular sludge treating abattoir wastewater and achieving high levels of nutrient removal was subjected to 4-5 week starvation under anaerobic and intermittent anaerobic/aerobic conditions. Microscopic pictures of granules at the beginning of the starvation period presented a round and compact surface morphology with a much defined external perimeter. Under both starvation conditions, the morphology changed at the end of starvation with the external border of the granules surrounded by floppy materials. The loss of granular compactness was faster and more pronounced under anaerobic/aerobic starvation conditions. The release of Ca(2+) at the onset of anaerobic/aerobic starvation suggests a degradation of extracellular polymeric substances. The activity of ammonia oxidizing bacteria was reduced by 20 and 36% during anaerobic and intermittent anaerobic/aerobic starvation, respectively. When fresh wastewater was reintroduced, the granules recovered their initial morphology within 1 week of normal operation and the nutrient removal activity recovered fully in 3 weeks. The results show that both anaerobic and intermittent anaerobic/aerobic conditions are suitable for maintaining granule structure and activity during starvation.

  8. 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.

  9. 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.

  10. Detection, diversity and expression of aerobic bacterial arsenite oxidase genes.

    PubMed

    Inskeep, William P; Macur, Richard E; Hamamura, Natsuko; Warelow, Thomas P; Ward, Seamus A; Santini, Joanne M

    2007-04-01

    The arsenic (As) drinking water crisis in south and south-east Asia has stimulated intense study of the microbial processes controlling the redox cycling of As in soil-water systems. Microbial oxidation of arsenite is a critical link in the global As cycle, and phylogenetically diverse arsenite-oxidizing microorganisms have been isolated from various aquatic and soil environments. However, despite progress characterizing the metabolism of As in various pure cultures, no functional gene approaches have been developed to determine the importance and distribution of arsenite-oxidizing genes in soil-water-sediment systems. Here we report for the first time the successful amplification of arsenite oxidase-like genes (aroA/asoA/aoxB) from a variety of soil-sediment and geothermal environments where arsenite is known to be oxidized. Prior to the current work, only 16 aroA/asoA/aoxB-like gene sequences were available in GenBank, most of these being putative assignments from homology searches of whole genomes. Although aroA/asoA/aoxB gene sequences are not highly conserved across disparate phyla, degenerate primers were used successfully to characterize over 160 diverse aroA-like sequences from 10 geographically isolated, arsenic-contaminated sites and from 13 arsenite-oxidizing organisms. The primer sets were also useful for confirming the expression of aroA-like genes in an arsenite-oxidizing organism and in geothermal environments where arsenite is oxidized to arsenate. The phylogenetic and ecological diversity of aroA-like sequences obtained from this study suggests that genes for aerobic arsenite oxidation are widely distributed in the bacterial domain, are widespread in soil-water systems containing As, and play a critical role in the biogeochemical cycling of As.

  11. Pollution-induced community tolerance and functional redundancy in a decomposer food web in metal-stressed soil.

    PubMed

    Salminen, J; van Gestel, C A; Oksanen, J

    2001-10-01

    Pollution may lead to the development of pollution-induced community tolerance (PICT) in a stressed community. We studied the presence of PICT in soil food webs using soil microcosms. Soil microcosms containing soil invertebrates and microbes were collected from polluted and unpolluted areas and exposed to a range of soil zinc concentrations. A pine seedling was planted in each microcosm to measure the effects of the origin of the community and Zn pollution on above-ground plant production. The effects of the treatments on nutrient content in the soil were also measured. The diversity of soil microarthropods and the soil's mineral nutrient content were low at the Zn-polluted site. We did not observe an increasing Zn tolerance among the soil organisms in the polluted soil. However, low population growth rates of soil invertebrates from the polluted site may indicate the deleterious effects on fitness of long-lasting pollution. In the soil from the nonpolluted site, Zn additions caused changes in the invertebrate food web structure. These changes were explained by the good physiological condition of the animals and their insensitivity to Zn. The fact that the food web structure in soil from the polluted site did not change can be used as a rough indicator of PICT. Structural stability is presumed by the lack of Zn-sensitive species at this site and the inability of populations to acclimate by altering their growth or reproduction patterns in response to changing soil conditions. Although microbial-based soil decomposer systems may have a high functional redundancy, our results indicate that metal stress at the polluted site exceeds the tolerance limits of the system. As a consequence, ecosystem function at this site is endangered. This study also shows that the evolution of metal tolerance by soil decomposer organisms may not be a common reaction to soil pollution, although changes of population and community structure indicated severe metal stress on organisms.

  12. Dental plaque microcosm biofilm behavior on calcium phosphate nanocomposite with quaternary ammonium

    PubMed Central

    Cheng, Lei; Weir, Michael D.; Zhang, Ke; Wu, Eric; Xu, Sarah M.; Zhou, Xuedong; Xu, Hockin H. K.

    2012-01-01

    Objectives Half of dental restorations fail in 10 years, with secondary caries as the main reason. Calcium phosphate composites could remineralize tooth lesions. The objectives of this study were to: (1) Impart antibacterial activity to a composite with nanoparticles of amorphous calcium phosphate (NACP); and (2) investigate the effect of quaternary ammonium dimethacrylate (QADM) on mechanical and dental plaque microcosm biofilm properties for the first time. Methods The NACP and glass particles were filled into a dental resin that contained bis(2-methacryloyloxy-ethyl) dimethyl-ammonium bromide, the QADM. NACP nanocomposites containing 0%, 7%, 14%, and 17.5% of QADM by mass, respectively, were photo-cured. A commercial composite with no antibacterial activity was used as control. Mechanical properties were measured in three-point flexure. A human saliva microcosm model was used to grow biofilms on composites. Live/dead assay, metabolic activity, colony-forming unit (CFU) counts, and lactic acid production of biofilms on the composites were measured. Results Increasing QADM mass fraction monotonically reduced the biofilm viability, CFU and lactic acid. Biofilms on NACP nanocomposite with 17.5% QADM had metabolic activity that was 30% that on a commercial composite control (p<0.05). Total microorganisms, total streptococci, and mutans streptococci CFU counts (mean±sd; n=6) on composite control was 6-fold those on NACP+17.5% QADM nanocomposite. Composite control had long strings of cells with normal short-rod shapes, while some cells on NACP-QADM nanocomposites disintegrated into pieces. Adding QADM to NACP did not decrease the strength and elastic modulus, which matched (p>0.1) those of a commercial composite without Ca-PO4 or antibacterial activity. Significance A dental plaque microcosm model was used to evaluate the novel NACP-QADM nanocomposite. The nanocomposite greatly reduced the biofilm viability, metabolic activity and lactic acid, while its mechanical

  13. 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.

  14. In Situ Dechlorination of Solvents in Saturated Soils

    DTIC Science & Technology

    1996-05-01

    dechlorination, while fermented yeast extract and sewage sludge supernatant are promising nutrient sources. Insight from these microbial and nutritional...competition for the supplied donor itself, as they (unlike MeOH) are not methanogenic. H2 is a direct fermentation product of these substrates. It is...NASF. 2.3 NASF SOIL MICROCOSM STUDIES In the laboratory, several electron donors have been demonstrated to stimulate anaerobic fermentation , H2

  15. 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.

  16. 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.

  17. Near-Complete Genome Sequence of Thalassospira sp. Strain KO164 Isolated from a Lignin-Enriched Marine Sediment Microcosm

    PubMed Central

    Woo, Hannah L.; O’Dell, Kaela B.; Utturkar, Sagar; McBride, Kathryn R.; Huntemann, Marcel; Clum, Alicia; Pillay, Manoj; Palaniappan, Krishnaveni; Varghese, Neha; Mikhailova, Natalia; Stamatis, Dimitrios; Reddy, T. B. K.; Ngan, Chew Yee; Daum, Chris; Shapiro, Nicole; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Woyke, Tanja; Brown, Steven D.

    2016-01-01

    Thalassospira sp. strain KO164 was isolated from eastern Mediterranean seawater and sediment laboratory microcosms enriched on insoluble organosolv lignin under oxic conditions. The near-complete genome sequence presented here will facilitate analyses into this deep-ocean bacterium’s ability to degrade recalcitrant organics such as lignin. PMID:27881538

  18. Near-Complete Genome Sequence of Thalassospira sp. Strain KO164 Isolated from a Lignin-Enriched Marine Sediment Microcosm.

    PubMed

    Woo, Hannah L; O'Dell, Kaela B; Utturkar, Sagar; McBride, Kathryn R; Huntemann, Marcel; Clum, Alicia; Pillay, Manoj; Palaniappan, Krishnaveni; Varghese, Neha; Mikhailova, Natalia; Stamatis, Dimitrios; Reddy, T B K; Ngan, Chew Yee; Daum, Chris; Shapiro, Nicole; Markowitz, Victor; Ivanova, Natalia; Kyrpides, Nikos; Woyke, Tanja; Brown, Steven D; Hazen, Terry C

    2016-11-23

    Thalassospira sp. strain KO164 was isolated from eastern Mediterranean seawater and sediment laboratory microcosms enriched on insoluble organosolv lignin under oxic conditions. The near-complete genome sequence presented here will facilitate analyses into this deep-ocean bacterium's ability to degrade recalcitrant organics such as lignin.

  19. 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 ...

  20. Litter quality indirectly influences community composition, reproductive mode and trophic structure of oribatid mite communities: a microcosm experiment.

    PubMed

    Gergócs, Veronika; Rétháti, Gabriella; Hufnagel, Levente

    2015-11-01

    Our knowledge of the assembly processes of species-rich oribatid mite communities is fairly limited. Also, very little information is available on the effects of habitat factors on these processes. In this paper, the role of litter quality in pattern formation was investigated in a microcosm experiment using the "home-field advantage" approach. Native (home) and foreign (away) types of microarthropod assemblages were extracted from three types of litter samples (Turkey oak, Scots pine and black locust tree), and transferred alive into 'home' and 'away' samples, which have been defaunated and reinoculated with microorganisms to form microcosms. Microarthropods were extracted from the microcosms after incubation for 3-12 months. In addition to species identification and abundance records, some chemical properties of the litter were measured. We hypothesized that oribatid mite communities deteriorate, the proportion of parthenogenetic individuals decreases and the proportion of omnivorous individuals increases in 'away' microcosms in contrast to 'home' systems. Pine and oak litter were favourable for all the three types of oribatid communities since their community traits in these types of litter were found to be similar to 'home' litter. Black locust litter was favourable only for its native oribatid community in the long run. The proportion of parthenogenetic individuals partly supported our hypothesis, mainly in black locust litter. The relative abundance of omnivorous individuals did not differ significantly between treatments. Litter quality is likely to influence oribatid mite assemblages only indirectly.

  1. The effect of co-substrate activation on indigenous and bioaugmented PCB dechlorinating bacterial communities in sediment microcosms.

    PubMed

    Park, Joong-Wook; Krumins, Valdis; Kjellerup, Birthe V; Fennell, Donna E; Rodenburg, Lisa A; Sowers, Kevin R; Kerkhof, Lee J; Häggblom, Max M

    2011-03-01

    Microbial reductive dechlorination by members of the phylum Chloroflexi, including the genus Dehalococcoides, may play an important role in natural detoxification of highly chlorinated environmental pollutants, such as polychlorinated biphenyls (PCBs). Previously, we showed the increase of an indigenous bacterial population belonging to the Pinellas subgroup of Dehalococcoides spp. in Anacostia River sediment (Washington DC, USA) microcosms treated with halogenated co-substrates ("haloprimers"), tetrachlorobenzene (TeCB), or pentachloronitrobenzene (PCNB). The PCNB-amended microcosms exhibited enhanced dechlorination of weathered PCBs, while TeCB-amended microcosms did not. We therefore developed and used different phylogenetic approaches to discriminate the effect of the two different haloprimers. We also developed complementary approaches to monitor the effects of haloprimer treatments on 12 putative reductive dehalogenase (rdh) genes common to Dehalococcoides ethenogenes strain 195 and Dehalococcoides sp. strain CBDB1. Our results indicate that 16S rRNA gene-based phylogenetic analyses have a limit in their ability to distinguish the effects of two haloprimer treatments and that two of rdh genes were present in high abundance when microcosms were amended with PCNB, but not TeCB. rdh gene-based phylogenetic analysis supports that these two rdh genes originated from the Pinellas subgroup of Dehalococcoides spp., which corresponds to the 16S rRNA gene-based phylogenetic analysis.

  2. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates

    NASA Astrophysics Data System (ADS)

    Patterson, B. M.; Aravena, R.; Davis, G. B.; Furness, A. J.; Bastow, T. P.; Bouchard, D.

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ13C - 5.2 to - 10.9‰) compared to groundwater (δ13C - 39.5‰) at the on-site location. Soil gas CO2 isotope analysis at both locations showed that CO2 was highly isotopically depleted (δ13C - 28.8 to - 33.3‰), compared to soil gas CO2 data originating from natural sediment organic matter (δ13C = - 14.7 to - 21.3‰). The soil gas CO2 δ13C values were consistent with near-water table VC groundwater δ13C values (- 36.8 to - 39.5‰), suggesting CO2 originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO2 concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour biodegradation

  3. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates.

    PubMed

    Patterson, B M; Aravena, R; Davis, G B; Furness, A J; Bastow, T P; Bouchard, D

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ¹³C -5.2 to -10.9‰) compared to groundwater (δ¹³C -39.5‰) at the on-site location. Soil gas CO₂ isotope analysis at both locations showed that CO₂ was highly isotopically depleted (δ¹³C -28.8 to -33.3‰), compared to soil gas CO₂ data originating from natural sediment organic matter (δ¹³C= -14.7 to -21.3‰). The soil gas CO2 δ¹³C values were consistent with near-water table VC groundwater δ¹³C values (-36.8 to -39.5‰), suggesting CO₂ originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE)) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO₂ concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour

  4. 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...

  5. Decreases in ammonia volatilization in response to greater plant diversity in microcosms of constructed wetlands

    NASA Astrophysics Data System (ADS)

    Luo, Bin; Ge, Ying; Han, Wenjuan; Fan, Xing; Ren, Yuan; Du, Yuanyuan; Shi, Mengmeng; Chang, Jie

    2016-10-01

    Ammonia volatilization from wastewaters with a high concentration of ammonium is a serious environmental and health problem. Constructed wetlands (CWs) are widely used for treating wastewater, and plant diversity clearly improves some functions of ecosystem such as nitrogen removal. However, whether plant diversity can affect ammonia volatilization from wastewater is still unknown. In this study, we conducted a microcosm experiment with different plant diversity treatments using four plant species. Results showed that, (1) ammonia volatilization decreased with increasing plant species richness; (2) ammonia volatilization from systems containing Rumex japonicus was lower than other systems; and (3) ammonia volatilization was affected more by species composition than species richness. This paper is the first to report that ammonia volatilization is reduced by plant diversity, and that some plant species combinations are important to reduce ammonia volatilization from CWs when treating wastewater.

  6. Experimental approach to follow the spatiotemporal wood degradation in fungal microcosms.

    PubMed

    Hahn, Felix; Ullrich, René; Hofrichter, Martin; Liers, Christiane

    2013-01-01

    To investigate the spatiotemporal growth dynamics in fungal microcosms and to follow the spatial degradation effects of fungal lignocellulose fermentation, a new and flexible experimental setup was developed and tested. White and brown rot fungi were cultivated under solid-state conditions in beech wood-filled silicon tubes for 5 weeks. After inoculation of wood material at one end of the tube, the culture vessels were aerated and moistured by flushing air through alkaline and aqueous solutions. After incubation, the silicon tubes were harvested and segmented to follow different growth and degradation parameters. This new approach holds great potential since it allows the use of different growth substrates, variable aeration or moisturization conditions and is therefore a useful tool for diverse degradation studies, e.g. respiration/mineralization studies involving flow meters or carbon dioxide sensors or for molecular biological approaches.

  7. 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.

  8. Positive priming of terrestrially derived dissolved organic matter in a freshwater microcosm system

    NASA Astrophysics Data System (ADS)

    Bianchi, Thomas S.; Thornton, Daniel C. O.; Yvon-Lewis, Shari A.; King, Gary M.; Eglinton, Timothy I.; Shields, Michael R.; Ward, Nicholas D.; Curtis, Jason

    2015-07-01

    The role of priming processes in the remineralization of terrestrially derived dissolved organic carbon (TDOC) in aquatic systems has been overlooked. We provide evidence for TDOC priming using a lab-based microcosm experiment in which TDOC was primed by the addition of 13C-labeled algal dissolved organic carbon (ADOC) or a 13C-labeled disaccharide (trehalose). The rate of TDOC remineralization to carbon dioxide (CO2) occurred 4.1 ± 0.9 and 1.5 ± 0.3 times more rapidly with the addition of trehalose and ADOC, respectively, relative to experiments with TDOC as the sole carbon source over the course of a 301 h incubation period. Results from these controlled experiments provide fundamental evidence for the occurrence of priming of TDOC by ADOC and a simple disaccharide. We suggest that priming effects on TDOC should be considered in carbon budgets for large-river deltas, estuaries, lakes, hydroelectric reservoirs, and continental shelves.

  9. 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.

  10. Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles: part 2-toxicity and Ag speciation.

    PubMed

    Bone, Audrey J; Colman, Benjamin P; Gondikas, Andreas P; Newton, Kim M; Harrold, Katherine H; Cory, Rose M; Unrine, Jason M; Klaine, Stephen J; Matson, Cole W; Di Giulio, Richard T

    2012-07-03

    To study the effects of complex environmental media on silver nanoparticle (AgNP) toxicity, AgNPs were added to microcosms with freshwater sediments and two species of aquatic plants (Potamogeton diversifolius and Egeria densa), followed by toxicity testing with microcosm surface water. Microcosms were designed with four environmental matrices in order to determine the contribution of each environmental compartment to changes in toxicity: water only (W), water + sediment (WS), water + plants (WP), and water + plants + sediment (WPS). Silver treatments included AgNPs with two different coatings, gum arabic (GA-AgNPs) or polyvinylpyrollidone (PVP-AgNPs), as well as AgNO(3). Water samples taken from the microcosms at 24 h postdosing were used in acute toxicity tests with two standard model organisms, early life stage zebrafish (Danio rerio) and Daphnia magna. Speciation of Ag in these samples was analyzed using Ag L3-edge X-ray absorption near edge spectroscopy (XANES). Silver speciation patterns for the nanoparticle treatments varied significantly by coating type. While PVP-AgNPs were quite stable and resisted transformation across all matrices (>92.4% Ag(0)), GA-AgNP speciation patterns suggest significantly higher transformation rates, especially in treatments with plants (<69.2% and <58.8% Ag(0) in WP and WPS, respectively) and moderately increased transformation with sediments (<85.6% Ag(0)). Additionally, the presence of plants in the microcosms (with and without sediments) reduced both the concentration of Ag in the water column and toxicity for all Ag treatments. Reductions in toxicity may have been related to decreased water column concentrations as well as changes in the surface chemistry of the particles induced by organic substances released from the plants.

  11. Therapeutic aspects of aerobic dance participation.

    PubMed

    Estivill, M

    1995-01-01

    An ethnographic analysis of aerobic dance exercise culture was conducted to determine the impact of the culture on the mind-body connection. After a review of the predominant theories on the relationship between vigorous exercise and elevated mood, aerobic dance participants' experiences are reported to illustrate how cognitive experience and self-esteem may be influenced. Interviews revealed that some participants achieved a pleasantly altered state of consciousness and respite from depression and stress. The relationship of the work ethic to achievement of participant satisfaction is underscored.

  12. The chemical and biological factors associated with ecosystem recovery from copper stress as exemplified by microcosms

    SciTech Connect

    Meador, J.P.

    1988-01-01

    The process of recovery from severe toxicant stress was examined in microcosms exposed to copper. The variables, algal and animal abundance, nutrient uptake, oxygen change, pH alkalinity, and the concentrations of total, dissolved, and ionic copper and dissolved organic carbon (DOC) were measured. Several process studies confirmed microcosm observations that algal metabolism was responsible for variation in pH and DOC concentration. It was demonstrated that these two parameters had a large influence on copper speciation and were responsible for ecosystem recovery. A complete three-factor, 48 hour bioassay was performed to assess the effects and interactions of DOC, pH and total copper on copper toxicity to Daphnia magma. A model using these 3 variables was developed which explained 84% of the variation in the determination of ionic copper. Mortality of Daphnia magma was modeled by using ionic copper as the dependent variable which explained 86% to 79% of the variation (at 24 and 48 hours). Variations in total copper concentration produced temporal variations in ecosystem recovery and the species dominance. Dissolved copper concentrations were correlated with pH values and consistently decreased to around 200 ppb (3:1 {mu}M) before algal recovery commenced. Dissolved copper concentrations were inadequate in explaining Daphnia magma toxicity when based on LC50 values. In this system, algal biomass, as an adsorbant, was shown to be insignificant in controlling copper toxicity. Alkalinity, which can be a major factor in copper speciation and toxicity, was also unimportant. It was determined that Daphnia magma populations were not inhibited when fed the copper-tolerant algal species, Oocystis pusilla, grown in a solution with a high copper concentration. Also, exposure to a high dissolved copper concentration did not confer resistance to copper toxicity in Daphnia magma.

  13. Liquid based formulations of bacteriophages for the management of waterborne bacterial pathogens in water microcosms.

    PubMed

    Ahiwale, Sangeeta; Tagunde, Sujata; Khopkar, Sushama; Karni, Mrudula; Gajbhiye, Milind; Kapadnis, Balasaheb

    2013-11-01

    Water resources are contaminated by life-threatening multidrug resistant pathogenic bacteria. Unfortunately, these pathogenic bacteria do not respond to the traditional water purification methods. Therefore, there is a need of environmentally friendly strategies to overcome the problems associated with the antimicrobial resistant bacterial pathogens. In the present study, highly potent lytic phages against multidrug-resistant Salmonella enterica serovar Paratyphi B, Pseudomonas aeruginosa and Klebsiella pneumoniae were isolated from the Pavana river water. They belonged to the Podoviridae and Siphoviridae families. These phages were purified and enriched in the laboratory. Monovalent formulations of phiSPB, BVPaP-3 and KPP phages were prepared in three different liquids viz., phage broth, saline and distilled water. The phages were stable for almost 8-10 months in the phage broth at 4 degrees C. The stability of the phages in saline and distilled water was 5-6 months at 4 degrees C. All of the phages were stable only for 4-6 months in the phage broth at 30 degrees C. The monovalent phage formulation of psiSPB was applied at MOI < 1, as disinfectant against an exponential and stationary phase cells of Salmonella enterica serovar Paratyphi B in various water microcosms. The results indicated that there was almost 80 % reduction in the log phase cells of Salmonella serovar Paratyphi B in 24 h. In stationary phase cells, the reduction was comparatively less within same period. At the same time, there was concomitant increase in the phage population by 80% in all the microcosms indicating that psiSPB phage is highly potent in killing pathogen in water. Results strongly support that the formulation of psiSPB in the phage broth in monovalent form could be used as an effective biological disinfectant for preventing transmission of water-borne bacterial pathogens, including antimicrobial resistant ones.

  14. 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.

  15. Effect of amorphous calcium phosphate and silver nanocomposites on dental plaque microcosm biofilms

    PubMed Central

    Cheng, Lei; Weir, Michael D.; Xu, Hockin H. K.; Antonucci, Joseph M.; Lin, Nancy J.; Lin-Gibson, Sheng; Xu, Sarah M.; Zhou, Xuedong

    2012-01-01

    A dental composite containing amorphous calcium phosphate nanoparticles (NACP) was developed that released calcium (Ca) and phosphate (PO4) ions and possessed acid-neutralization capability. There has been little study on incorporation of antibacterial agents into calcium phosphate composites. The objective of this study was to investigate the effect of silver nanoparticle (NAg) mass fraction in NACP nanocomposite on mechanical properties and dental plaque microcosm biofilm for the first time. NACP nanoparticles of 116 nm were synthesized via a spray-drying technique. NAg nanoparticles were synthesized using Ag 2-ethylhexanoate and 2-(tert-butylamino)ethyl methacrylate, yielding NAg of particle size of 2.7 nm that were well-dispersed in the resin. Five NACP nanocomposites were fabricated with NAg mass fractions of 0, 0.028, 0.042, 0.088, and 0.175%, respectively. Mechanical properties of NACP nanocomposites containing 0–0.042% of NAg matched those of a commercial composite without antibacterial activity. Live/dead assay of dental plaque microcosm biofilms showed complete coverage with live bacteria on commercial composite. However, there were increasingly more dead bacteria with higher NAg content in the NACP nanocomposite. Colony-forming unit (CFU) counts for total microorganisms, total Streptococci, and mutans Streptococci for NACP nanocomposite with 0.042% NAg were about 1/4 those of commercial composite. Lactic acid production on NACP nanocomposite with 0.042% NAg was 1/3 that on commercial composite. In conclusion, novel NACP–NAg nanocomposites were developed which possessed good mechanical properties and potent antibacterial properties, with substantially reduced biofilm viability and lactic acid production. Hence, the NACP–NAg nanocomposites are promising for dental restorations with remineralizing and antibacterial capabilities. PMID:22566464

  16. 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.

  17. 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.

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

    PubMed Central

    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

  19. 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,...

  20. Soil invertebrate fauna affect N2 O emissions from soil.

    PubMed

    Kuiper, Imke; de Deyn, Gerlinde B; Thakur, Madhav P; van Groenigen, Jan Willem

    2013-09-01

    Nitrous oxide (N2 O) emissions from soils contribute significantly to global warming. Mitigation of N2 O emissions is severely hampered by a lack of understanding of its main controls. Fluxes can only partly be predicted from soil abiotic factors and microbial analyses - a possible role for soil fauna has until now largely been overlooked. We studied the effect of six groups of soil invertebrate fauna and tested the hypothesis that all of them increase N2 O emissions, although to different extents. We conducted three microcosm experiments with sandy soil and hay residue. Faunal groups included in our experiments were as follows: fungal-feeding nematodes, mites, springtails, potworms, earthworms and isopods. In experiment I, involving all six faunal groups, N2 O emissions declined with earthworms and potworms from 78.4 (control) to 37.0 (earthworms) or 53.5 (potworms) mg N2 O-N m(-2) . In experiment II, with a higher soil-to-hay ratio and mites, springtails and potworms as faunal treatments, N2 O emissions increased with potworms from 51.9 (control) to 123.5 mg N2 O-N m(-2) . Experiment III studied the effect of potworm density; we found that higher densities of potworms accelerated the peak of the N2 O emissions by 5 days (P < 0.001), but the cumulative N2 O emissions remained unaffected. We propose that increased soil aeration by the soil fauna reduced N2 O emissions in experiment I, whereas in experiment II N2 O emissions were driven by increased nitrogen and carbon availability. In experiment III, higher densities of potworms accelerated nitrogen and carbon availability and N2 O emissions, but did not increase them. Overall, our data show that soil fauna can suppress, increase, delay or accelerate N2 O emissions from soil and should therefore be an integral part of future N2 O studies.

  1. 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.

  2. 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…

  3. 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…

  4. 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...

  5. Aerobic exercise in fibromyalgia: a practical review.

    PubMed

    Thomas, Eric N; Blotman, Francis

    2010-07-01

    The objective of the study was to determine the current evidence to support guidelines for aerobic exercise (AE) and fibromyalgia (FM) in practice, and to outline specific research needs in these areas. Data sources consisted of a PubMed search, 2007 Cochrane Data Base Systematic review, 2008 Ottawa panel evidence-based clinical practice guidelines, as well as additional references found from the initial search. Study selection included randomized clinical trials that compared an aerobic-only exercise intervention (land or pool based) with an untreated control, a non-exercise intervention or other exercise programs in patients responding to the 1990 American College of Rheumatology criteria for FM. The following outcome data were obtained: pain, tender points, perceived improvement in FM symptoms such as the Fibromyalgia Impact Questionnaire total score (FIQ), physical function, depression (e.g., Beck Depression Inventory, FIQ subscale for depression), fatigue and sleep were extracted from 19 clinical trials that considered the effects of aerobic-only exercise in FM patients. Data synthesis shows that there is moderate evidence of important benefit of aerobic-only exercise in FM on physical function and possibly on tender points and pain. It appears to be sufficient evidence to support the practice of AE as a part of the multidisciplinary management of FM. However, future studies must be more adequately sized, homogeneously assessed, and monitored for adherence, to draw definitive conclusions.

  6. 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...

  7. 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, and…

  8. 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).…

  9. 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.

  10. Assessment of trace element accumulation by earthworms in an orchard soil remediation study using soil amendments

    USGS Publications Warehouse

    Centofantia, Tiziana; Chaney, Rufus L.; Beyer, W. Nelson; McConnell, Laura L.; Davis, A. P.; Jackson, Dana

    2016-01-01

    This study assessed potential bioaccumulation of various trace elements in grasses and earthworms as a consequence of soil incorporation of organic amendments for in situ remediation of an orchard field soil contaminated with organochlorine and Pb pesticide residues. In this experiment, four organic amendments of differing total organic carbon content and quality (two types of composted manure, composted biosolids, and biochar) were added to a contaminated orchard field soil, planted with two types of grasses, and tested for their ability to reduce bioaccumulation of organochlorine pesticides and metals in earthworms. The experiment was carried out in 4-L soil microcosms in a controlled environment for 90 days. After 45 days of orchardgrass or perennial ryegrass growth, Lumbricus terrestris L. were introduced to the microcosms and exposed to the experimental soils for 45 days before the experiment was ended. Total trace element concentrations in the added organic amendments were below recommended safe levels and their phytoavailablity and earthworm availability remained low during a 90-day bioremediation study. At the end of the experiment, total tissue concentrations of Cu, Cd, Mn, Pb, and Zn in earthworms and grasses were below recommended safe levels. Total concentrations of Pb in test soil were similar to maximum background levels of Pb recorded in soils in the Eastern USA (100 mg kg−1 d.w.) because of previous application of orchard pesticides. Addition of aged dairy manure compost and presence of grasses was effective in reducing the accumulation of soil-derived Pb in earthworms, thus reducing the risk of soil Pb entry into wildlife food chains.

  11. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  13. Aerobic exercise training in modulation of aerobic physical fitness and balance of burned patients.

    PubMed

    Ali, Zizi M Ibrahim; El-Refay, Basant H; Ali, Rania Reffat

    2015-03-01

    [Purpose] This study aimed to determine the impact of aerobic exercise on aerobic capacity, balance, and treadmill time in patients with thermal burn injury. [Subjects and Methods] Burned adult patients, aged 20-40 years (n=30), from both sexes, with second degree thermal burn injuries covering 20-40% of the total body surface area (TBSA), were enrolled in this trial for 3 months. Patients were randomly divided into; group A (n=15), which performed an aerobic exercise program 3 days/week for 60 min and participated in a traditional physical therapy program, and group B (n=15), which only participated in a traditional exercise program 3 days/week. Maximal aerobic capacity, treadmill time, and Berg balance scale were measured before and after the study. [Results] In both groups, the results revealed significant improvements after treatment in all measurements; however, the improvement in group A was superior to that in group B. [Conclusion] The results provide evidence that aerobic exercises for adults with healed burn injuries improve aerobic physical fitness and balance.

  14. Combined effects of bacterial-feeding nematodes and prometryne on the soil microbial activity.

    PubMed

    Zhou, Jihai; Li, Xuechao; Jiang, Ying; Wu, Yue; Chen, Jiandong; Hu, Feng; Li, Huixin

    2011-09-15

    Microcosm experiments were carried out to study the effects of bacterial-feeding nematodes and indigenous microbes and their interactions on the degradation of prometryne and soil microbial activity in contaminated soil. The results showed that soil indigenous microbes could degrade prometryne up to 59.6-67.9%; bacterial-feeding nematodes accelerated the degradation of prometryne in contaminated soil, and prometryne degradation was raised by 8.36-10.69%. Soil microbial biomass C (C(mic)), basal soil respiration (BSR), and respiratory quotient (qCO(2)) increased in the beginning of the experiment and decreased in the later stage of the experiment. Nematodes grew and reproduced quite fast, and did increase the growth of soil microbes and enhance soil microbial activity in prometryne contaminated soil during the incubation period.

  15. Survival, sublethal injury, and recovery of environmental Burkholderia pseudomallei in soil subjected to desiccation.

    PubMed

    Larsen, Eloise; Smith, James J; Norton, Robert; Corkeron, Maree

    2013-04-01

    Environmental Burkholderia pseudomallei isolated from sandy soil at Castle Hill, Townsville, in the dry tropic region of Queensland, Australia, was inoculated into sterile-soil laboratory microcosms subjected to variable soil moisture. Survival and sublethal injury of the B. pseudomallei strain were monitored by recovery using culture-based methods. Soil extraction buffer yielded higher recoveries as an extraction agent than sterile distilled water. B. pseudomallei was not recoverable when inoculated into desiccated soil but remained recoverable from moist soil subjected to 91 days' desiccation and showed a growth response to increased soil moisture over at least 113 days. Results indicate that endemic dry tropic soil may act as a reservoir during the dry season, with an increase in cell number and potential for mobilization from soil into water in the wet season.

  16. 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.

  17. 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.

  18. Influence of triethyl phosphate on phosphatase activity in shooting range soil: Isolation of a zinc-resistant bacterium with an acid phosphatase.

    PubMed

    Story, Sandra; Brigmon, Robin L

    2017-03-01

    Phosphatase-mediated hydrolysis of organic phosphate may be a viable means of stabilizing heavy metals via precipitation as a metal phosphate in bioremediation applications. We investigated the effect of triethyl phosphate (TEP) on soil microbial-phosphatase activity in a heavy-metal contaminated soil. Gaseous TEP has been used at subsurface sites for bioremediation of organic contaminants but not applied in heavy-metal contaminated areas. Little is known about how TEP affects microbial activity in soils and it is postulated that TEP can serve as a phosphate source in nutrient-poor groundwater and soil/sediments. Over a 3-week period, TEP amendment to microcosms containing heavy-metal contaminated soil resulted in increased activity of soil acid-phosphatase and repression of alkaline phosphatase, indicating a stimulatory effect on the microbial population. A soil-free enrichment of microorganisms adapted to heavy-metal and acidic conditions was derived from the TEP-amended soil microcosms using TEP as the sole phosphate source and the selected microbial consortium maintained a high acid-phosphatase activity with repression of alkaline phosphatase. Addition of 5mM zinc to soil-free microcosms had little effect on acid phosphatase but inhibited alkaline phosphatase. One bacterial member from the consortium, identified as Burkholderia cepacia sp., expressed an acid-phosphatase activity uninhibited by high concentrations of zinc and produced a soluble, indigo pigment under phosphate limitation. The pigment was produced in a phosphate-free medium and was not produced in the presence of TEP or phosphate ion, indicative of purple acid-phosphatase types that are pressed by bioavailable phosphate. These results demonstrate that TEP amendment was bioavailable and increased overall phosphatase activity in both soil and soil-free microcosms supporting the possibility of positive outcomes in bioremediation applications.

  19. Aerobic microbial manufacture of nanoscale selenium: exploiting nature's bio-nanomineralization potential.

    PubMed

    Tejo Prakash, N; Sharma, Neetu; Prakash, Ranjana; Raina, Kuldeep K; Fellowes, Jonathan; Pearce, Carolyn I; Lloyd,