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Sample records for 300a subsurface sediments

  1. Fe(III) Reduction and U(VI) Immobilization by Paenibacillus sp. Strain 300A, Isolated from Hanford 300A Subsurface Sediments

    SciTech Connect

    Ahmed, B.; Cao, B.; McLean, Jeffrey S.; Ica, Tuba; Dohnalkova, Alice; Istanbullu, Ozlem; Paksoy, Akin; Fredrickson, Jim K.; Beyenal, Haluk

    2012-11-07

    A facultative iron-reducing (Fe(III)-reducing) Paenibacillus sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes (Fe(III)-NTA and Fe(III)-citrate) but unable to reduce poorly crystalline ferrihydrite (Fh). However, Paenibacillus sp. 300A was capable of reducing Fh in the presence of low concentrations (2 µM) of either of electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 µM) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We found that Paenibacillus sp. 300A also could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs, Paenibacillus sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ~7:3 in PIPES and ~1:4 in bicarbonate buffer. Our study demonstrated that Paenibacillus sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments.

  2. Controls on Microbial Transport in Subsurface Sediments

    NASA Astrophysics Data System (ADS)

    Szecsody, J. E.

    2005-12-01

    Laboratory-scale measurements of microbial transport indicate that most microbes attach to subsurface sediments. Given this attachment, it is unclear how microbes are transported significant distances in deep aquifers. It was hypothesized that attachment/detachment mechanisms are dynamic responses to nutrient availability, so that transport is dependent upon the presence/absence of electron donors and acceptors. For one microbial isolate of the Shewanella strain CN-32 there was high attachment in the presence of both electron donor and acceptor, and very little attachment if no donor or acceptor were present. In addition, CN-32 exhibited chemotatic movement through electron donor/acceptor gradients. A series of batch, 1-D homogeneous, 1-D heterogeneous, and 2-D heterogeneous experiments were conducted to quantify CN-32 Monod parameters and to assess the relative importance of simple attachment/detachment steps, dynamic growth/detachment steps, and chemotaxis. Three models included dual Monod kinetics for a single electron donor (lactate), two electron acceptors (dissolved oxygen and nitrate), and either: a) constant microbial attachment (adsorption), b) attachment linked to the presence of electron donor/acceptor, or c) chemotaxis. Simulations of batch experiments using quantified Monod parameters could not predict 1-D experimental results without accounting for microbial attachment. With constant input of electron donor/acceptors, microbial attachment could be well approximated assuming constant microbial adsorption. However, advection of input pulses of electron donor/acceptors resulted in much further downgradient migration, which could be simulated assuming an empirical growth/detachment reaction. The 2-D experimental system with microbes that received input pulses of electron donor/acceptors (idealized representation of an aquifer) showed that that both chemotaxis and the dynamic growth/detachment mechanisms were needed to approximate microbial movement over

  3. Metabolic activity of subsurface life in deep-sea sediments.

    PubMed

    D'Hondt, Steven; Rutherford, Scott; Spivack, Arthur J

    2002-03-15

    Global maps of sulfate and methane in marine sediments reveal two provinces of subsurface metabolic activity: a sulfate-rich open-ocean province, and an ocean-margin province where sulfate is limited to shallow sediments. Methane is produced in both regions but is abundant only in sulfate-depleted sediments. Metabolic activity is greatest in narrow zones of sulfate-reducing methane oxidation along ocean margins. The metabolic rates of subseafloor life are orders of magnitude lower than those of life on Earth's surface. Most microorganisms in subseafloor sediments are either inactive or adapted for extraordinarily low metabolic activity.

  4. Hydrogen Utilization Potential in Subsurface Sediments.

    PubMed

    Adhikari, Rishi R; Glombitza, Clemens; Nickel, Julia C; Anderson, Chloe H; Dunlea, Ann G; Spivack, Arthur J; Murray, Richard W; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones.

  5. Hydrogen Utilization Potential in Subsurface Sediments

    PubMed Central

    Adhikari, Rishi R.; Glombitza, Clemens; Nickel, Julia C.; Anderson, Chloe H.; Dunlea, Ann G.; Spivack, Arthur J.; Murray, Richard W.; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones. PMID:26858697

  6. Plasmid incidence in bacteria from deep subsurface sediments

    SciTech Connect

    Fredrickson, J.K.; Hicks, R.J.; Li, S.W.; Brockman, F.J. )

    1988-12-01

    Bacteria were isolated from deep terrestrial subsurface sediments underlying the coastal plain of South Carolina. A total of 163 isolates from deep sediments, surface soil, and return drill muds were examined for plasmid DNA content and resistance to the antibiotics penicillin, ampicillin, carbenicillin, streptomycin, kanamycin, and tetracycline. MICs of Cu{sup 2+}, Cr{sup 3+}, and Hg{sup 2+} for each isolate were also determined. The overall frequency of plasmid occurrence in the subsurface bacteria was 33%. Resistance was most frequent to penicillin (70% of all isolates), ampicillin (49%), and carbenicillin (32%) and was concluded to be related to the concentrations of the individual antibiotics in the disks used for assaying resistance and to the production of low levels of {beta}-lactamase. The frequencies of resistance to penicillin and ampicillin were significantly greater for isolates bearing plasmids than for plasmidless isolates; however, resistance was not transferable to penicillin-sensitive Escherichia coli. Hybridization of subsurface bacterial plasmids and chromosomal DNA with a whole-TOL-plasmid (pWWO) probe revealed some homology of subsurface bacterial plasmid and chromosomal DNAs, indicating a potential for those bacterial to harbor catabolic genes on plasmids or chromosomes. The incidences of antibiotic resistance and MICs of metals for subsurface bacteria were significantly different from those drill mud bacteria, ruling out the possibility that bacteria from sediments were derived from drill muds.

  7. Metabolically active microbial communities in uranium-contaminated subsurface sediments.

    PubMed

    Akob, Denise M; Mills, Heath J; Kostka, Joel E

    2007-01-01

    In order to develop effective bioremediation strategies for radionuclide contaminants, the composition and metabolic potential of microbial communities need to be better understood, especially in highly contaminated subsurface sediments for which little cultivation-independent information is available. In this study, we characterized metabolically active and total microbial communities associated with uranium-contaminated subsurface sediments along geochemical gradients. DNA and RNA were extracted and amplified from four sediment-depth intervals representing moderately acidic (pH 3.7) to near-neutral (pH 6.7) conditions. Phylotypes related to Proteobacteria (Alpha-, Beta-, Delta- and Gammaproteobacteria), Bacteroidetes, Actinobacteria, Firmicutes and Planctomycetes were detected in DNA- and RNA-derived clone libraries. Diversity and numerical dominance of phylotypes were observed to correspond to changes in sediment geochemistry and rates of microbial activity, suggesting that geochemical conditions have selected for well-adapted taxa. Sequences closely related to nitrate-reducing bacteria represented 28% and 43% of clones from the total and metabolically active fractions of the microbial community, respectively. This study provides the first detailed analysis of total and metabolically active microbial communities in radionuclide-contaminated subsurface sediments. Our microbial community analysis, in conjunction with rates of microbial activity, points to several groups of nitrate-reducers that appear to be well adapted to environmental conditions common to radionuclide-contaminated sites.

  8. Effect of Extent of Natural Subsurface Bioreduction on Fe-mineralogy of Subsurface Sediments

    SciTech Connect

    Kukkadapu, Ravi K.; Qafoku, Nikolla; Arey, Bruce W.; Resch, Charles T.; Long, Philip E.

    2010-05-16

    Naturally bioreduced zones with considerable sorbed U were recently identified at a former U mining and processing site at Rifle, CO, USA. Most of the sorbed U appears to be associated with Fe minerals. Variably reduced sediment samples were analyzed by suite of techniques, primarily by room temperature Mössbauer spectroscopy. Fe-oxides of different types and crystallinity, and Fe(II)/Fe(III)-containing clays are dominant in all the sediments. The amounts of poorly crystalline Fe(III)-oxide, however, was lower in the reduced samples. In addition, framboidal pyrites with sorbed U were common in the highly reduced sediments. Overall, the information gained from this work may help develop design field strategies for immobilization and stabilization of U(VI) in contaminated subsurface environments.

  9. Distribution and activity of hydrogenase enzymes in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Adhikari, R.; Nickel, J.; Glombitza, C.; Spivack, A. J.; D'Hondt, S. L.; Kallmeyer, J.

    2013-12-01

    Metabolically active microbial communities are present in a wide range of subsurface environments. Techniques like enumeration of microbial cells, activity measurements with radiotracer assays and the analysis of porewater constituents are currently being used to explore the subsurface biosphere, alongside with molecular biological analyses. However, many of these techniques reach their detection limits due to low microbial activity and abundance. Direct measurements of microbial turnover not just face issues of insufficient sensitivity, they only provide information about a single specific process rather than an overall microbial activity. Since hydrogenase enzymes are intracellular and ubiquitous in subsurface microbial communities, the enzyme activity represents a measure of total activity of the entire microbial community. A hydrogenase activity assay could quantify total metabolic activity without having to identify specific processes. This would be a major advantage in subsurface biosphere studies, where several metabolic processes can occur simultaneously. We quantified hydrogenase enzyme activity and distribution in sediment samples from different aquatic subsurface environments (Lake Van, Barents Sea, Equatorial Pacific and Gulf of Mexico) using a tritium-based assay. We found enzyme activity at all sites and depths. Volumetric hydrogenase activity did not show much variability between sites and sampling depths, whereas cell-specific activity ranged from 10-5 to 1 nmol H2 cell-1 d-1. Activity was lowest in sediment layers where nitrate was detected. Higher activity was associated with samples in which sulfate was the predominant electron acceptor. We found highest activity in samples from environments with >10 ppm methane in the pore water. The results show that cell-specific hydrogenase enzyme activity increases with decreasing energy yield of the electron acceptor used. It is not possible to convert volumetric or cell-specific hydrogenase activity into a

  10. Iodide Sorption to Subsurface Sediments and Illitic Minerals

    SciTech Connect

    Kaplan, D.I.; Serne, R.J.; Parker, K.E.; Kutnyakov, I.V.

    2000-01-01

    Laboratory studies were conducted to quantify and identify the key processes by which iodide (I{sup {minus}}) sorbs to subsurface arid sediments. A surprisingly large amount of I{sup {minus}} sorbed to three alkaline subsurface sediments that were low in organic matter content; distribution coefficients (K{sub d}'s) ranged from 1 to 10 mL/g and averaged 3.3 mL/g. Experiments with pure mineral isolates, similar to the minerals identified in the clay fraction of the sediments, showed that there was little or no I{sup {minus}} sorption to calcite (K{sub d} = 0.04 {+-} 0.01 mL/g), chlorite (K{sub d} = {minus}0.22 {+-} 0.06 mL/g), goethite (K{sub d} = 0.10 {+-} 0.03 mL/g), montmorillonite (K{sub d} = {minus}0.42 {+-} 0.08 mL/g), quartz (K{sub d} = 0.04 {+-} 0.02 mL/g), or vermiculite (K{sub d} = 0.56 {+-} 0.21 mL/g). Conversely, a significant amount of I{sup {minus}} sorbed to illite (K{sub d} = 15.14 {+-} 2.84 mL/g). Treating the {sup 125}I{sup {minus}}-laden illite mixtures with dissolved F{sup {minus}}, Cl{sup {minus}}, Br{sup {minus}}, or {sup 127}I{sup {minus}}, caused 43 {+-} 3%, 45 {+-} 0%, 52 {+-} 3%, and 83 {+-} 1%, respectively, of the adsorbed I{sup {minus}} to desorb. Finally, I{sup {minus}} sorption to illite was strongly pH-dependent; the K{sub d} values decreased from 46 to 22 mL/g as the pH values increased from 3.6 to 9.4. An appreciable amount of I{sup {minus}} sorbed to illite even under alkaline conditions. These experiments suggest that illite removed I{sup {minus}} from the aqueous phase predominantly by reversible physical adsorption to the pH-dependent edge sites. Illites may constitute a substantial proportion of the clay-size fraction of many arid sediments and therefore may play an important role in retarding I{sup {minus}} movement in these sediments.

  11. Iodide sorption to subsurface sediments and illitic minerals

    SciTech Connect

    Kaplan, D.I.; Serne, R.J.; Parker, K.E.; Kutnyakov, I.V.

    2000-02-01

    Laboratory studies were conducted to quantify and identify the key processes by which iodide (I{sup {minus}}) sorbs to subsurface arid sediments. A surprisingly large amount of I{sup {minus}} sorbed to three alkaline subsurface sediments that were low in organic matter content; distribution coefficients (K{sub d}'s) ranged from 1 to 10 mL/g and averaged 3.3 mL/g. Experiments with pure mineral isolates, similar to the minerals identified in the clay fraction of the sediments, showed that there was little or no I{sup {minus}} sorption to calcite (K{sub d} = 0.04 {+-} 0.01 mL/g), chlorite (K{sub d} = {minus}0.22 {+-} 0.06 mL/g), goethite (K{sub d} = 0.10 {+-} 0.03 mL/g), montmorillonite (K{sub d} = {minus}0.42 {+-} 0.08 mL/g), quartz (K{sub d} = 0.04 {+-} 0.02 mL/g), or vermiculite (K{sub d} = 0.56 {+-} 0.21 mL/g). Conversely, a significant amount of I{sup {minus}} sorbed to illite (K{sub d} = 15.14 {+-} 2.84 mL/g). Treating the {sup 125}I{sup {minus}}-laden illite mixtures with dissolved F{sup {minus}}, Cl{sup {minus}}, Br{sup {minus}}, or {sup 127}I{sup {minus}}, caused 43 {+-} 3%, 45 {+-} 0%, 52 {+-} 3%, and 83 {+-} 1%, respectively, of the adsorbed I{sup {minus}} to desorb. Finally, I{sup {minus}} sorption to illite was strongly pH-dependent; the K{sub d} values decreased from 46 to 22 mL/g as the pH values increased from 3.6 to 9.4. An appreciable amount of I{sup {minus}} sorbed to illite even under alkaline conditions. These experiments suggest that illite removed I{sup {minus}} from the aqueous phase predominantly by reversible physical adsorption to the pH-dependent edge sites. Illites may constitute a substantial proportion of the clay-size fraction of many arid sediments and therefore may play an important role in retarding I{sup {minus}} movement in these sediments.

  12. Iodide sorption to subsurface sediments and illitic minerals

    SciTech Connect

    Kaplan, Daniel I.; Serne, R. Jeffrey; Parker, Kent E.; Kutnyakov, Igor V.

    2000-02-01

    Laboratory studies were conducted to quantify and understand the processes by which iodide (I-) adsorbs to subsurface arid sediments. A surprisingly large amount of I- sorbed (distribution coefficients [Kd?s] ranged from 1 to 10 mL/g and averaged 3.3 mL/g) to three alkaline subsurface sediments that were low in organic matter content. Experiments with pure mineral isolates, similar to the minerals identified in the clay fraction of the sediments, showed that there was little or no I- sorption. The pure minerals that had low iodide sorption include montmorillonite (Kd = -0.42 +/- 0.08 mL/g), quartz (Kd = 0.04 +/- 0.02 mL/g), vermiculite (Kd = 0.56 +/- 0.21 mL/g), calcite (Kd = 0.04 +/- 0.01 mL/g), goethite (Kd = 0.10 +/- 0.03 mL/g), or chlorite (Kd = -0.22 +/- 0.06 mL/g). Conversely, a significant amount of I- sorbed to illite (Kd = 15.14 +/- 2.84 mL/g). Upon treating the iodide-laden illite with dissolved F-, Cl-, Br-, or I-127, desorption (or isotopic exchange in the case of I-127) removed, respectively, 57 +/- 3%, 55 +/- 0%, 48 +/- 3, and 17 +/- 1% of the I- originally adsorbed to the illite. The fact that such large amounts of I- could be desorbed suggests that the I- was weakly adsorbed, and not chemically bonded to a soft metal, such as mercury or silver, that may have existed in the illite structure as trace impurities. Finally, I- sorption to illite was strongly pH-dependent; the Kd values decreased from 46 to 22 mL/g as the pH increased from 3.6 to 9.4. Importantly, I- sorbed to illite even under alkaline conditions. Together, these experiments suggest that illite removed I- from the aqueous phase predominantly by reversible physical adsorption to the pH-dependent edge sites. Illites may constitute a substantial proportion of the clay-size fraction of many arid sediments and therefore may play an important role in retarding I- movement in these sediments.

  13. Radiolytic hydrogen and microbial respiration in subsurface sediments.

    PubMed

    Blair, Carly C; D'Hondt, Steven; Spivack, Arthur J; Kingsley, Richard H

    2007-12-01

    Radiolysis of water may provide a continuous flux of an electron donor (molecular hydrogen) to subsurface microbial communities. We assessed the significance of this process in anoxic marine sediments by comparing calculated radiolytic H(2) production rates to estimates of net (organic-fueled) respiration at several Ocean Drilling Program (ODP) Leg 201 sites. Radiolytic H(2) yield calculations are based on abundances of radioactive elements (uranium, thorium, and potassium), porosity, grain density, and a model of water radiolysis. Net respiration estimates are based on fluxes of dissolved electron acceptors and their products. Comparison of radiolytic H(2) yields and respiration at multiple sites suggests that radiolysis gains importance as an electron donor source as net respiration and organic carbon content decrease. Our results suggest that radiolytic production of H(2) may fuel 10% of the metabolic respiration at the Leg 201 site where organic-fueled respiration is lowest (ODP Site 1231). In sediments with even lower rates of organic-fueled respiration, water radiolysis may be the principal source of electron donors. Marine sedimentary ecosystems may be useful models for non-photosynthetic ecosystems on early Earth and on other planets and moons, such as Mars and Europa.

  14. Storms as agents of wetland elevation change: their impact on surface and subsurface sediment processes

    USGS Publications Warehouse

    Cahoon, D.R.

    2003-01-01

    Direct measures of the impact of major storms on wetland sediment elevation are rare. Recently developed techniques have enabled simultaneous, quantitative observations of surface and subsurface processes affecting sediment elevation. An analysis of ten wetland sites revealed the following patterns of sediment elevation change after storm passage: (1) elevation change equivalent to sediment accretion or erosion, (2) elevation loss in spite of sediment deposition, or in excess of erosion, and (3) elevation gain greater than the amount of sediment accretion. These observations suggest that storms influence sediment elevation not only by sediment deposition and erosion but also through subsurface processes of sediment compaction, root growth and decomposition, and water flux. Wetlands receiving a substantial deposit of sediment did not always realize an equivalent elevation gain. Some realized a net loss in elevation as a result of sediment compaction apparently caused by the weight of the sediment deposit or the tidal surge waters, or both. Sediment elevation collapsed in two mangrove forests with highly organic substrate when the storm killed the forest. In two marshes, elevation gain exceeded deposition apparently through increased sediment water storage or plant root growth via nutrient enrichment from storm sediment deposits. The elevation responses were either temporary or permanent on an ecological time scale (> 8 years). In one organic marsh substrate, compaction was followed by expansion, only to be compacted again by another storm. Thus the elevation response of coastal wetlands to major storms varied depending on local substrate conditions and degree of storm impact.

  15. NEPTUNIUM IV AND V SORPTIN TO END-MEMBER SUBSURFACE SEDIMENTS TO THE SAVANNAH RIVER SITE

    SciTech Connect

    Kaplan, D.

    2009-11-13

    Migration of Np through the subsurface is expected to be primarily controlled by sorption to sediments. Therefore, understanding and quantifying Np sorption to sediments and sediments from the Savannah River Site (SRS) is vital to ensure safe disposal of Np bearing wastes. In this work, Np sorption to two sediments representing the geological extremes with respect to sorption properties expected in the SRS subsurface environment (named 'subsurface sandy sediment' and 'subsurface clayey sediment') was examined under a variety of conditions. First a series of baseline sorption tests at pH 5.5 under an oxic atmosphere was performed to understand Np sorption under typical subsurface conditions. These experiments indicated that the baseline K{sub d} values for the subsurface sandy and subsurface clayey sediments are 4.26 {+-} 0.24 L kg{sup -1} and 9.05 {+-} 0.61 L kg{sup -1}, respectively. These Np K{sub d} values of SRS sediments are the first to be reported since Sheppard et al. (1979). The previous values were 0.25 and 0.16 L kg{sup -1} for a low pH sandy sediment. To examine a possible range of K{sub d} values under various environmental scenarios, the effects of natural organic matter (NOM, also a surrogate for cellulose degradation products), the presence of various chemical reductants, and an anaerobic atmosphere on Np sorption were examined. The presence of NOM resulted in an increase in the Np K{sub d} values for both sediments. This behavior is hypothesized to be the result of formation of a ternary Np-NOM-sediment complex. Slight increases in the Np sorption (K{sub d} 13-24 L kg{sup -1}) were observed when performing experiments in the presence of chemical reductants (dithionite, ascorbic acid, zero-valent iron) or under anaerobic conditions. Presumably, the increased sorption can be attributed to a slight reduction of Np(V) to Np(IV), the stronger sorbing form of Np. The most significant result of this study is the finding that Np weakly sorbs to both end

  16. Sediment delivery from agricultural land to rivers via subsurface drainage

    NASA Astrophysics Data System (ADS)

    Chapman, A. S.; Foster, I. D. L.; Lees, J. A.; Hodgkinson, R. A.

    2005-10-01

    Diffuse sources of sediment and sediment-associated nutrients are of increasing environmental concern because of their impacts on receiving water courses. The aim of the research reported here was to monitor the outflow from four field (land) drains at two farms in the English Midlands in order to estimate the quantity of sediment delivered to the local rivers and the most likely sources and processes involved. A multiparameter sediment unmixing model was employed, using environmental magnetic, geochemical and radionuclide tracers in order to determine the most likely origin of sediments transported through the drains. Results demonstrated that there was a generally linear relationship between drainflow sediment loss and drainflow volume and that the majority (>70%) of the sediment exported from the drains was derived from topsoil. Macropore flow through heavily cracked soils is supported by the data to be the most likely means of sediment delivery to the drains. In one catchment, drains contributed over 50% of the annual sediment budget. Spatial and temporal variations in the sources of sediment reaching one drain outlet were investigated in detail. A link between soil moisture deficit (SMD) and the frequency of high-intensity rainfall events was used to explain the appearance and persistence of a new sediment source in this drain after October 1998. It is concluded that field drains have the potential to be significant conduits of sediment and agrochemicals in a wide variety of environments in the UK. It is also suggested that this potential may increase if projected climate change leads to more intense rainfall events and increases in SMD across a greater area of the UK.

  17. High virus-to-cell ratios indicate ongoing production of viruses in deep subsurface sediments.

    PubMed

    Engelhardt, Tim; Kallmeyer, Jens; Cypionka, Heribert; Engelen, Bert

    2014-07-01

    Marine sediments cover two-thirds of our planet and harbor huge numbers of living prokaryotes. Long-term survival of indigenous microorganisms within the deep subsurface is still enigmatic, as sources of organic carbon are vanishingly small. To better understand controlling factors of microbial life, we have analyzed viral abundance within a comprehensive set of globally distributed subsurface sediments. Phages were detected by electron microscopy in deep (320 m below seafloor), ancient (∼14 Ma old) and the most oligotrophic subsurface sediments of the world's oceans (South Pacific Gyre (SPG)). The numbers of viruses (10(4)-10(9) cm(-3), counted by epifluorescence microscopy) generally decreased with sediment depth, but always exceeded the total cell counts. The enormous numbers of viruses indicate their impact as a controlling factor for prokaryotic mortality in the marine deep biosphere. The virus-to-cell ratios increased in deeper and more oligotrophic layers, exhibiting values of up to 225 in the deep subsurface of the SPG. High numbers of phages might be due to absorption onto the sediment matrix and a diminished degradation by exoenzymes. However, even in the oldest sediments, microbial communities are capable of maintaining viral populations, indicating an ongoing viral production and thus, viruses provide an independent indicator for microbial life in the marine deep biosphere.

  18. Distribution of subsurface hydrocarbon seepage in near surface marine sediments

    SciTech Connect

    Abrams, M.A. )

    1993-02-01

    Hydrocarbon seeps in surficial marine sediments are of two types: ACTIVE: Where gas bubbles, pockmarks, or bright spots are visible on seismic records and/or the presence of chemosynthetic communities in conjunction with large concentrations of migrated-hydrocarbons. Generally in areas where generation and migration of hydrocarbons from the source rock is ongoing today (i.e., maximum burial) and/or where significant migration pathways have developed from tectonic activity. PASSIVE: Where concentrations of migrated hydrocarbons are so low that few or no geophysical anomalies are seen. Typically in areas where generation and expulsion is relict (no longer at maximum burial) and/or regional seals prevent significant vertical migration. The type of seep strongly controls the distribution of migrated hydrocarbons in the near surface sediments and should dictate the sampling equipment and approach required to detect seeps. Active seeps or macroseeps, usually can be detected near the water-sediment interface, within the water column, and at relatively large distances from major leak points. Most conventional sediment and water samplers will capture active seeps, Precise location of sampling is typically not critical to detect active seeps. The Gulf of Mexico, Santa Barbara Channel, and parts of the North Sea have active hydrocarbon seeps.

  19. Final report - Microbial pathways for the reduction of mercury in saturated subsurface sediments

    SciTech Connect

    Tamar barkay; Lily Young; Gerben Zylstra

    2009-08-25

    Mercury is a component of mixed wastes that have contaminated vast areas of the deep subsurface as a result of nuclear weapon and energy production. While this mercury is mostly bound to soil constituents episodes of groundwater contamination are known in some cases resulting in potable water super saturated with Hg(0). Microbial processes that reduce Hg(II) to the elemental form Hg(0) in the saturated subsurface sediments may contribute to this problem. When we started the project, only one microbial pathway for the reduction of Hg(II), the one mediated by the mer operon in mercury resistant bacteria was known. As we had previously demonstrated that the mer mediated process occurred in highly contaminated environments (Schaefer et al., 2004), and mercury concentrations in the subsurface were reported to be low (Krabbenhoft and Babiarz, 1992), we hypothesized that other microbial processes might be active in reducing Hg(II) to Hg(0) in saturated subsurface environments. The specific goals of our projects were: (1) Investigating the potential for Hg(II) reduction under varying electron accepting conditions in subsurface sediments and relating these potential to mer gene distribution; and (2) Examining the physiological and biochemical characteristics of the interactions of anaerobic bacteria with mercury. The results are briefly summarized with references to published papers and manuscripts in preparation where details about our research can be found. Additional information may be found in copies of our published manuscripts and conference proceedings, and our yearly reports that were submitted through the RIMS system.

  20. The role of prokaryotes in subsurface weathering of hydrothermal sediments: A combined geochemical and microbiological investigation

    NASA Astrophysics Data System (ADS)

    Severmann, Silke; Mills, Rachel A.; Palmer, Martin R.; Telling, Jon P.; Cragg, Barry; John Parkes, R.

    2006-04-01

    A detailed geochemical and microbiological study of a ˜2 m sediment core from the inactive Alvin mounds within the TAG hydrothermal field was conducted to examine, for the first time, the role of prokaryotes in subsurface weathering of hydrothermal sediments. Results show that there has been substantial post-depositional remobilisation of metal species and diagenetic overprinting of the original high-temperature hydrothermal minerals, and aspects have involved prokaryotic processes. Prokaryotic enumeration demonstrates the presence of a population smaller than the average for deep sea sediments, probably due to the low organic carbon content, but not inhibited by (and hence adapted to) the metal rich environment. There was a small but significant increase in population size associated with the active redox boundary in an upper metal sulphide layer (50-70 cm) around which active metal remobilisation was concentrated (Cu, Au, Cd, Ag, U, Zn and Zn). Hence, subsurface prokaryotes were potentially obtaining energy from metal metabolism in this near surface zone. Close association of numbers of culturable Mn and Fe reducing prokaryotes with subsurface Fe 2+ and Mn 2+ pore water profiles suggested active prokaryotic metal reduction at depth in core CD102/43 (to ˜175 cm). In addition, a prokaryotic mechanism, which is associated with bacterial sulphate reduction, is invoked to explain the U enrichment on pyrite surfaces and Zn and Pb remobilisation in the upper sediment. Although prokaryotic populations are present throughout this metalliferous sediment, thermodynamic calculations indicated that the inferred low pH of pore waters and the suboxic/anoxic conditions limits the potential energy available from Fe(II) oxidation, which may restrict prokaryotic chemolithotrophic biomass. This suggests that intense prokaryotic Fe oxidation and weathering of seafloor massive sulphide deposits may be restricted to the upper portion of the deposit that is influenced by near neutral

  1. Sediment mobilization deposits from episodic subsurface fluid flow - A new tool to reveal long-term earthquake records?

    NASA Astrophysics Data System (ADS)

    Reusch, Anna; Moernaut, Jasper; Anselmetti, Flavio S.; Strasser, Michael

    2016-04-01

    Subsurface fluid flow can be affected by earthquakes: increased spring activity, mud volcano eruptions, groundwater fluctuations, changes in geyser frequency and other forms of altered subsurface fluid flow have been documented during, after, or even prior to earthquakes. Recently discovered giant pockmarks on the bottom of Lake Neuchâtel, Switzerland, are the lake-floor expression of subsurface fluid flow. They discharge karstic groundwater from the Jura Mountains and experience episodically increased subsurface fluid flow documented by subsurface sediment mobilization deposits at the levees of the pockmarks. In this study, we present the spatio-temporal distribution of event deposits from phases of sediment expulsion and their time correlative multiple mass-transport deposits. We report striking evidence for five events of concurrent multiple subsurface sediment deposits and multiple mass-transport deposits since Late Glacial times, for which we propose past earthquakes as trigger. Comparison of this new event catalogue with historic earthquakes and other independent paleoseismic records suggests that initiation of sediment expulsion requires a minimum macroseismic intensity of VII. Thus, our study presents for the first time sedimentary deposits resulting from increased subsurface fluid flow as new paleoseismic proxy. Comparable processes must also be relevant for other mountain front ranges and coastal mountain ranges, where groundwater flow triggers subsurface sediment mobilization and discharges into lacustrine and marine settings.

  2. Methane production from protozoan endosymbionts following stimulation of microbial metabolism within subsurface sediments.

    PubMed

    Holmes, Dawn E; Giloteaux, Ludovic; Orellana, Roberto; Williams, Kenneth H; Robbins, Mark J; Lovley, Derek R

    2014-01-01

    Previous studies have suggested that protozoa prey on Fe(III)- and sulfate-reducing bacteria that are enriched when acetate is added to uranium contaminated subsurface sediments to stimulate U(VI) reduction. In order to determine whether protozoa continue to impact subsurface biogeochemistry after these acetate amendments have stopped, 18S rRNA and ß-tubulin sequences from this phase of an in situ uranium bioremediation field experiment were analyzed. Sequences most similar to Metopus species predominated, with the majority of sequences most closely related to M. palaeformis, a cilitated protozoan known to harbor methanogenic symbionts. Quantification of mcrA mRNA transcripts in the groundwater suggested that methanogens closely related to Metopus endosymbionts were metabolically active at this time. There was a strong correlation between the number of mcrA transcripts from the putative endosymbiotic methanogen and Metopus ß-tubulin mRNA transcripts during the course of the field experiment, suggesting that the activity of the methanogens was dependent upon the activity of the Metopus species. Addition of the eukaryotic inhibitors cyclohexamide and colchicine to laboratory incubations of acetate-amended subsurface sediments significantly inhibited methane production and there was a direct correlation between methane concentration and Metopus ß-tubulin and putative symbiont mcrA gene copies. These results suggest that, following the stimulation of subsurface microbial growth with acetate, protozoa harboring methanogenic endosymbionts become important members of the microbial community, feeding on moribund biomass and producing methane.

  3. Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site

    SciTech Connect

    Xu, Chen; Kaplan, Daniel I.; Zhang, Saijin; Athon, Matthew; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris; Schwehr, Kathy; Grandbois, Russell; Wellman, Dawn M.; Santschi, Peter H.

    2015-01-01

    During the last few decades, considerable research efforts have been extended to identify more effective remediation treatment technologies to lower the 129I concentrations to below federal drinking water standards at the Hanford Site (Richland, USA). Few studies have taken iodate into consideration, though recently iodate, instead of iodide, was identified as the major species in the groundwater of 200-West Area within the Hanford Site. The objective of this study was thus to quantify and understand aqueous radioiodine species transformations and uptake by three sediments collected from the semiarid, carbonate-rich environment of the Hanford subsurface. All three sediments reduced iodate (IO-) to iodide (I-), but the loamy-sand sediment reduced more IO3- (100% reduced within 7 days) than the two sand-textured sediments (~20% reduced after 28 days). No dissolved organo-iodine species were observed in any of these studies.

  4. Biogeography and diversity of methane and sulfur-cycling ecotypes in deep subsurface sediments

    NASA Astrophysics Data System (ADS)

    Adams, M. M.; Biddle, J.; Girguis, P. R.

    2013-12-01

    The microbially mediated anaerobic oxidation of methane (AOM) is critical for regulating the flux of methane from the ocean. AOM is coupled to sulfate availability in many anoxic marine environments, which has been extensively studied at cold seeps, hydrothermal vents, and the sulfate-methane transition zone at the seafloor. The microbes known to catalyze AOM form phylogenetically distinct anaerobic methanotroph (ANME) clusters and sometimes live in concert with sulfate-reducing bacteria (SRB). Strikingly, certain ANME groups and subgroups have been shown to occupy different ecological niches in both hydrocarbon seep and hydrothermal vent sediments. However, the environmental parameters that select for certain phylogenetic variants or 'ecotypes' in a wide range of marine systems are still unknown. A marine environment that remains elusive to characterization of potential ANME and SRB ecotype diversity is methane hydrate formations in the deep subsurface. Current estimates indicate that seafloor hydrates may exceed 10,000 GtC at standard temperature and pressure conditions. However, only a handful of studies have investigated the potential for AOM in the deep subsurface associated with methane hydrates. To gain a better understanding of the distribution of methane- and sulfur- cycling ecotypes in biogeochemically distinct marine subsurface ecosystems, we generated a substantial library of 16S rRNA gene sequences for these uncultivable deep sea microorganisms using Illumina sequencing. Sediment strata were collected from the methane-hydrate associated deep subsurface of Hydrate Ridge (30 - 100 mbsf), hydrocarbon cold seeps of Monterey Bay, metalliferous sedimented hydrothermal vents of Juan de Fuca Ridge, and organic-rich hydrothermally influenced sediments of Guaymas Basin. We used the Illumina MiSeq sequencing platform to assess Archaeal and Bacterial richness in a total of 36 deep sea sediment samples followed by qPCR for quantification of ANME and SRB phylotype

  5. Don Quixote Pond Sediments: Surface and Subsurface Chemistry and Mineralogy

    NASA Astrophysics Data System (ADS)

    Englert, P. A. J.; Bishop, J. L.; Patel, S.; Gibson, E. K.; Koeberl, C.

    2014-12-01

    Don Quixote Pond, like Don Juan Pond in the South Fork of Wright Valley, Antarctica, is a model for calcium and chlorine weathering and distribution on Mars. It is located in the western part of the North Fork about 100 m above Mean Seawater Level; its brine is seasonally frozen [1]. Field observations show zones of discoloration which grow lighter with distance from the pond edges. Four sediment cores, a set of radial surface samples, special surface samples, and samples of local rocks were obtained [2]. We report on chemical and mineral analyses of traverse samples and on two cores. Core DQ20 is a northeastern shoreline core. Its soluble salt concentration exceeds 200 micromoles/g in the top 5 cm, and then falls to less than 70 micromoles/g at the permafrost depth of 15 cm. These concentrations are low when compared to similarly positioned locations at Don Juan Pond and to cores from Prospect Mesa close to Lake Vanda, Wright Valley. Halite, soda niter, tachyhydrite and/bischovite are suggested from the ionic molar relationships Measured halite concentrations of surface samples, collected along a traverse of 35 m from the pond outwards, range from over 5% to trace amounts, decreasing with distance. Gypsum is also present in almost all of these samples ranging from 0.2% to 2.6%, but does not exhibit a trend. However, in core DQ35, located at a distance of 15 m along the traverse, gypsum decreases from 2.5% to 0.6% from the surface to the permafrost depth of 12 cm. While DQ35 and radial samples show high quartz and albite abundance, samples that contained visible encrustations and evaporites are low in these minerals and rich in highly diverse alteration products. Don Juan Basin ponds may have formed by a complex surface water mobilization of weathering products [3] and local groundwater action [4,5]. In contrast, Don Quixote pond mineralogy and chemistry may be consistent with a less complex shallow and deep groundwater system origin [1]. [1] Harris H

  6. In situ expression of nifD in Geobacteraceae in subsurface sediments

    USGS Publications Warehouse

    Holmes, Dawn E.; Nevin, Kelly P.; Lovely, Derek R.

    2004-01-01

    In order to determine whether the metabolic state of Geobacteraceae involved in bioremediation of subsurface sediments might be inferred from levels of mRNA for key genes, in situ expression of nifD, a highly conserved gene involved in nitrogen fixation, was investigated. When Geobacter sulfurreducens was grown without a source of fixed nitrogen in chemostats with acetate provided as the limiting electron donor and Fe(III) as the electron acceptor, levels of nifD transcripts were 4 to 5 orders of magnitude higher than in chemostat cultures provided with ammonium. In contrast, the number of transcripts of recA and the 16S rRNA gene were slightly lower in the absence of ammonium. The addition of acetate to organic- and nitrogen-poor subsurface sediments stimulated the growth of Geobacteraceae and Fe(III) reduction, as well as the expression of nifD in Geobacteraceae. Levels of nifD transcripts in Geobacteraceae decreased more than 100-fold within 2 days after the addition of 100 μM ammonium, while levels of recA and total bacterial 16S rRNA in Geobacteraceae remained relatively constant. Ammonium amendments had no effect on rates of Fe(III) reduction in acetate-amended sediments or toluene degradation in petroleum-contaminated sediments, suggesting that other factors, such as the rate that Geobacteraceae could access Fe(III) oxides, limited Fe(III) reduction. These results demonstrate that it is possible to monitor one aspect of the in situ metabolic state of Geobacteraceae species in subsurface sediments via analysis of mRNA levels, which is the first step toward a more global analysis of in situ gene expression related to nutrient status and stress response during bioremediation by Geobacteraceae.

  7. Immobilization and Natural Attenuation of Arsenic in Surface and Subsurface Sediments

    NASA Astrophysics Data System (ADS)

    O'Day, P. A.; Illera, V.; Choi, S.; Vlassopoulos, D.

    2008-12-01

    Understanding of molecular-scale biogeochemical processes that control the mobilization and distribution of As and other oxyanions can be used to develop remediation strategies that take advantage of natural geochemical and hydrologic gradients. Arsenic and other toxic oxyanions can be mobilized at low bulk sediment concentrations (ppm range) and thus, treatment technologies are challenged by low contaminant concentrations, widespread sources, variable pH and Eh conditions, and inaccessibility of subsurface environments. In situ chemical amendments to soils and sediments can be used to decrease the mobility and bioaccessibility of As and oxyanions through sorption to, or precipitation with, stabilizing phases. At a site near San Francisco Bay (CA, USA), treatment of As-contaminated soils with sulfate-cement amendments has effectively immobilized As. Laboratory experiments with field soils and spectroscopic characterizations showed that in high pH cement-type treatments, As is precipitated in ettringite-type phases (Ca-Al sulfates), whereas in low pH ferrous sulfate treatments, As is associated with an iron-arsenate phase (angellelite). The presence of As-associated ettringite-type phases in field sediments amended more than a decade ago indicates long-term stability of these neophases, as long as environmental conditions are relatively constant. At sites of subsurface contamination, monitored natural attenuation (MNA) as a remediation approach for As is gaining interest and acceptance. Successful implementation of MNA requires a mechanistic understanding of As sequestration processes and of the subsurface conditions that may enhance or reduce long-term effectiveness. At a former military site (MA, USA), naturally occurring As was mobilized from sediments as a result of reducing conditions from addition of organic carbon as a biodegradation treatment of chlorinated solvents. Elevated As concentrations were not detected further than about 30 m downgradient of the

  8. Electron flow in acidic subsurface sediments co-contaminated with nitrate and uranium

    NASA Astrophysics Data System (ADS)

    Edwards, Lainie; Küsel, Kirsten; Drake, Harold; Kostka, Joel E.

    2007-02-01

    The combination of low pH and high concentrations of nitrate and radionuclides in the subsurface is representative of many sites within the U.S. nuclear weapons complex managed by the Department of Energy (DOE), including the DOE's Environmental Remediation Sciences Program Field Research Center (ORFRC), in Oak Ridge, Tennessee. In order to provide a further understanding of the coupled microbiological and geochemical processes limiting radionuclide bioremediation, we determined the rates and pathways of terminal-electron accepting processes (TEAPs) in microcosm experiments using close to in situ conditions with ORFRC subsurface materials. At the in situ pH range of 4-5, carbon substrate utilization and TEAP rates were diminished, such that nitrate was not depleted and metal reduction was prevented. Upon biostimulation by pH neutralization and carbon substrate addition, TEAPs were stimulated to rates that rival those measured in organic-rich surficial sediments of aquatic environments, and extremely high nitrate concentrations (0.4-0.5 M) were not found to be toxic to microbial metabolism. Metal reduction under neutral pH conditions started once nitrate was depleted to low levels in response to biostimulation. Acidity controlled not only the rates but also the pathways of microbial activity. Denitrification predominated in sediments originating from neutral pH zones, while dissimilatory nitrate reduction to ammonium occurred in neutralized acidic microcosms amended with glucose. Electron donors were determined to stimulate microbial metabolism leading to metal reduction in the following order: glucose > ethanol > lactate > hydrogen. In microcosms of neutralized acidic sediments, 80-90% of C equivalents were recovered as fermentation products, mainly as acetate. Due to the stress imposed by low pH on microbial metabolism, our results indicate that the TEAPs of acidic subsurface sediment are inherently different from those of neutral pH environments and

  9. Mobilization of arsenic from subsurface sediments by effect of bicarbonate ions in groundwater.

    PubMed

    Anawar, Hossain M; Akai, Junji; Sakugawa, Hiroshi

    2004-02-01

    Arsenic leaching by bicarbonate ions has been investigated in this study. Subsurface sediment samples from Bangladesh were treated with different carbonate and bicarbonate ions and the results demonstrate that the arsenic leaching efficiency of the carbonate solutions decreased in the order of Na2CO3>NaHCO3>BaCO3>MnCO3. Sodium carbonate and bicarbonate ions extracted arsenic most efficiently; Na2CO3 leached maximum 118.12 microg/l of arsenic, and NaHCO3, 94.56 microg/l of arsenic from the Ganges delta sediments after six days of incubation. The arsenic concentrations extracted in the batch experiments correlated very well with the bicarbonate concentrations. The kinetics study of arsenic release indicates that arsenic-leaching rate increased with reaction time in bicarbonate solutions. Bicarbonate ions can extract arsenic from sediment samples in both oxic and anoxic conditions. A linear relationship found between arsenic contents in core samples and those in leachates suggests that dissolved arsenic concentration in groundwater is related to the amount of arsenic in aquifer sediments. In batch experiment, bicarbonate solutions effectively extracted arsenic from arsenic adsorbed iron oxyhydroxide, reflecting that bicarbonate solutions may mobilize arsenic from iron and manganese oxyhydroxide in sediments that are ubiquitous in subsurface core samples. Carbonate ion may form complexes on the surface sites of iron hydroxide and substitute arsenic from the surface of minerals and sediments resulting in release of arsenic to groundwater. Like in the batch experiment, arsenic and bicarbonate concentrations in groundwater of Bangladesh correlated very well. Therefore, bicarbonate leaching is presumed to be one important mechanism to mobilize arsenic in bicarbonate dominated reducing aquifer of Bangladesh and other parts of the world as well.

  10. Immobilization of cobalt by sulfate-reducing bacteria in subsurface sediments

    USGS Publications Warehouse

    Krumholz, Lee R.; Elias, Dwayne A.; Suflita, Joseph M.

    2003-01-01

    We investigated the impact of sulfate-reduction on immobilization of metals in subsurface aquifers. Co 2+ was used as a model for heavy metals. Factors limiting sulfate-reduction dependent Co 2+ immobilization were tested on pure cultures of sulfate-reducing bacteria, and in sediment columns from a landfill leachate contaminated aquifer. In the presence of 1 mM Co 2+ , the growth of pure cultures of sulfate-reducing bacteria was not impacted. Cultures of Desulfovibrio desulfuricans, Desulfotomaculum gibsoniae , and Desulfomicrobium hypogeia removed greater than 99.99% of the soluble Co 2+ when CoCl 2 was used with no chelators. The above cultures and Desulfoarcula baarsi removed 98-99.94% of the soluble Co(II) when the metal was complexed with the model ligand nitrilotriacetate (Co-NTA). Factors controlling the rate of sulfate-reduction based Co 2+ precipitation were investigated in sediment-cobalt mixtures. Several electron donors were tested and all but toluene accelerated soluble Co 2+ loss. Ethanol and formate showed the greatest stimulation. All complex nitrogen sources tested slowed and decreased the extent of Co 2+ removal from solution relative to formate-amended sediment incubations. A range of pH values were tested (6.35-7.81), with the more alkaline incubations exhibiting the largest precipitation of Co 2+ . The immobilization of Co 2+ in sediments was also investigated with cores to monitor the flow of Co 2+ through undisturbed sediments. An increase in the amount of Co 2+ immobilized as CoS was observed as sulfate reduction activity was stimulated in flow through columns. Both pure culture and sediment incubation data indicate that stimulation of sulfate reduction is a viable strategy in the immobilization of contaminating metals in subsurface systems.

  11. Marine Subsurface Microbial Community Shifts Across a Hydrothermal Gradient in Okinawa Trough Sediments.

    PubMed

    Brandt, Leah D; House, Christopher H

    2016-01-01

    Sediments within the Okinawa back-arc basin overlay a subsurface hydrothermal network, creating intense temperature gradients with sediment depth and potential limits for microbial diversity. We investigated taxonomic changes across 45 m of recovered core with a temperature gradient of 3°C/m from the dynamic Iheya North Hydrothermal System. The interval transitions sharply from low-temperature marine mud to hydrothermally altered clay at 10 meters below seafloor (mbsf). Here, we present taxonomic results from an analysis of the 16S rRNA gene that support a conceptual model in which common marine subsurface taxa persist into the subsurface, while high temperature adapted archaeal taxa show localized peaks in abundances in the hydrothermal clay horizons. Specifically, the bacterial phylum Chloroflexi accounts for a major proportion of the total microbial community within the upper 10 mbsf, whereas high temperature archaea (Terrestrial Hot Spring Crenarchaeotic Group and methanotrophic archaea) appear in varying local abundances in deeper, hydrothermal clay horizons with higher in situ temperatures (up to 55°C, 15 mbsf). In addition, geochemical evidence suggests that methanotrophy may be occurring in various horizons. There is also relict DNA (i.e., DNA preserved after cell death) that persists in horizons where the conditions suitable for microbial communities have ceased.

  12. Marine Subsurface Microbial Community Shifts Across a Hydrothermal Gradient in Okinawa Trough Sediments

    PubMed Central

    2016-01-01

    Sediments within the Okinawa back-arc basin overlay a subsurface hydrothermal network, creating intense temperature gradients with sediment depth and potential limits for microbial diversity. We investigated taxonomic changes across 45 m of recovered core with a temperature gradient of 3°C/m from the dynamic Iheya North Hydrothermal System. The interval transitions sharply from low-temperature marine mud to hydrothermally altered clay at 10 meters below seafloor (mbsf). Here, we present taxonomic results from an analysis of the 16S rRNA gene that support a conceptual model in which common marine subsurface taxa persist into the subsurface, while high temperature adapted archaeal taxa show localized peaks in abundances in the hydrothermal clay horizons. Specifically, the bacterial phylum Chloroflexi accounts for a major proportion of the total microbial community within the upper 10 mbsf, whereas high temperature archaea (Terrestrial Hot Spring Crenarchaeotic Group and methanotrophic archaea) appear in varying local abundances in deeper, hydrothermal clay horizons with higher in situ temperatures (up to 55°C, 15 mbsf). In addition, geochemical evidence suggests that methanotrophy may be occurring in various horizons. There is also relict DNA (i.e., DNA preserved after cell death) that persists in horizons where the conditions suitable for microbial communities have ceased. PMID:28096736

  13. Microbially catalyzed nitrate-dependent metal/radionuclide oxidation in shallow subsurface sediments

    NASA Astrophysics Data System (ADS)

    Weber, K.; Healy, O.; Spanbauer, T. L.; Snow, D. D.

    2011-12-01

    Anaerobic, microbially catalyzed nitrate-dependent metal/radionuclide oxidation has been demonstrated in a variety of sediments, soils, and groundwater. To date, studies evaluating U bio-oxidation and mobilization have primarily focused on anthropogenically U contaminated sites. In the Platte River Basin U originating from weathering of uranium-rich igneous rocks in the Rocky Mountains was deposited in shallow alluvial sediments as insoluble reduced uranium minerals. These reduced U minerals are subject to reoxidation by available oxidants, such nitrate, in situ. Soluble uranium (U) from natural sources is a recognized contaminant in public water supplies throughout the state of Nebraska and Colorado. Here we evaluate the potential of anaerobic, nitrate-dependent microbially catalyzed metal/radionuclide oxidation in subsurface sediments near Alda, NE. Subsurface sediments and groundwater (20-64ft.) were collected from a shallow aquifer containing nitrate (from fertilizer) and natural iron and uranium. The reduction potential revealed a reduced environment and was confirmed by the presence of Fe(II) and U(IV) in sediments. Although sediments were reduced, nitrate persisted in the groundwater. Nitrate concentrations decreased, 38 mg/L to 30 mg/L, with increasing concentrations of Fe(II) and U(IV). Dissolved U, primarily as U(VI), increased with depth, 30.3 μg/L to 302 μg/L. Analysis of sequentially extracted U(VI) and U(IV) revealed that virtually all U in sediments existed as U(IV). The presence of U(IV) is consistent with reduced Fe (Fe(II)) and low reduction potential. The increase in aqueous U concentrations with depth suggests active U cycling may occur at this site. Tetravalent U (U(IV)) phases are stable in reduced environments, however the input of an oxidant such as oxygen or nitrate into these systems would result in oxidation. Thus co-occurrence of nitrate suggests that nitrate could be used by bacteria as a U(IV) oxidant. Most probable number

  14. Potential for nonenzymatic reduction of Fe(III) via electron shuttling in subsurface sediments

    USGS Publications Warehouse

    Nevin, Kelly P.; Lovely, Derek R.

    2000-01-01

    The potential for various substances to serve as electron shuttles between Fe(III)-reducing microorganisms and insoluble Fe(III) oxides in aquifer sediments was evaluated in order to determine whether abiological mechanisms might play a role in the apparent microbial reduction of Fe(III) in subsurface sediments. Humic substances (humics) and the humics analogue, anthraquinone-2,6-disulfonate (AQDS), which were previously found to stimulate microbial reduction of synthetic poorly crystalline Fe(III) oxide under laboratory conditions, were found to also stimulate the reduction of aquifer Fe(III) oxides by indigenous microorganisms. Electron shuttling via biological reduction of U(VI) or S° followed by abiological reduction of Fe(III) by U(IV) or sulfide enhanced the reduction of synthetic Fe(III) oxide in cell suspensions, but these potential electron shuttles did not stimulate Fe(III) reduction when they were added to aquifer sediments. These results emphasize the importance of evaluating potential mechanisms for Fe(III) reduction with natural Fe(III) oxides, under environmentally relevant conditions. The finding that humics and other extracellular quinones can serve as electron shuttles to the Fe(III) oxides found in subsurface environments suggests that some Fe(III) reduction which was previously considered to be the result of direct enzymatic reduction of Fe(III) oxides may instead result from abiotic reduction of Fe(III) by microbially reduced humics or other microbially generated hydroquinones.

  15. Marine Subsurface Microbial Communities Across a Hydrothermal Gradient in Okinawa Trough Sediments

    NASA Astrophysics Data System (ADS)

    Brandt, L. D.; Hser Wah Saw, J.; Ettema, T.; House, C. H.

    2015-12-01

    IODP Expedition 331 to the Okinawa backarc basin provided an opportunity to study the microbial stratigraphy within the sediments surrounding a hydrothermal vent. The Okinawa backarc basin is a sedimented region of the seafloor located on a continental margin, and also hosts a hydrothermal network within the subsurface. Site C0014 within the Iheya North hydrothermal field is located 450 m east of the active vent and has a surface temperature of 5°C with no evidence of hydrothermal alteration within the top 10 meters below sea floor (mbsf). Temperature increases with depth at an estimated rate of 3°C/m and transitions from non-hydrothermal margin sediments to a hydrothermally altered regime below 10 mbsf. In this study, we utilized deep 16S rRNA sequencing of DNA from IODP Expedition 331 Site C0014 sediment horizons in order to assess diversity throughout the sediment column as well as determine the potential limits of the biosphere. Analysis of the amplicon data shows a shift over 15 mbsf from a heterogeneous community of cosmopolitan marine subsurface taxa toward an archaeal-dominated community in the deepest horizons of the predicted biosphere. Notably, the phylum Chloroflexi represents a substantial taxon through most horizons, where it appears to be replaced below 10 mbsf by punctuations of thermophilic and methanotrophic Archaea and Miscellaneous Crenarchaeotic Group abundances. DNA from the aforementioned transition horizons was further analyzed using metagenomic sequencing. Preliminary taxonomic analysis of the metagenomic data agrees well with amplicon data in capturing the shift in relative abundance of Archaea increasing with depth. Additionally, reverse gyrase, a gene found exclusively in hyperthermophilic microorganisms, was recovered only in the metagenome of the deepest horizon. A BLAST search of this protein sequence against the GenBank non-redudnant protein database produced top hits with reverse gyrase from Thermococcus and Pyrococcus, which are

  16. The microbial methane cycle in subsurface sediments. Final project report, July 1, 1993--August 31, 1997

    SciTech Connect

    Grossman, E.L.; Ammerman, J.W.; Suflita, J.M.

    1997-12-31

    The objectives of this study were to determine the factors controlling microbial activity and survival in the subsurface and, specifically, to determine whether microbial communities in aquitards and in aquifer microenvironments provide electron donors and/or acceptors that enhance microbial survival in aquifers. Although the original objectives were to focus on methane cycling, the authors pursued an opportunity to study sulfur cycling in aquifer systems, a process of much greater importance in microbial activity and survival, and in the mobility of metals in the subsurface. Furthermore, sulfur cycling is pertinent to the Subsurface Science Program`s study at Cerro Negro, New Mexico. The study combined field and laboratory approaches and microbiological, molecular, geochemical, and hydrogeological techniques. During drilling operations, sediments were collected aseptically and assayed for a variety of microorganisms and metabolic capabilities including total counts, viable aerobic heterotrophs, total anaerobic heterotrophs, sulfate reducing bacteria (SRB) and sulfate reduction activity (in situ and in slurries), methanogens, methanotrophs, and Fe- and S-oxidizers, among others. Geochemical analyses of sediments included organic carbon content and {sup 13}C/{sup 12}C ratio, sulfur chemistry (reduced sulfur, sulfate), {sup 34}S/{sup 32}S, {sup 13}C/{sup 12}C, {sup 14}C, tritium, etc. The authors drilled eight boreholes in the Eocene Yegua formation at four localities on the Texas A&M University campus using a hollow-stem auger drilling rig. The drilling pattern forms a T, with three well clusters along the dip direction and two along strike. Four boreholes were sampled for sediments and screened at the deepest sand interval encountered, and four boreholes were drilled to install wells in shallower sands. Boreholes range in depth from 8 to 31 m, with screened intervals ranging from 6 to 31 m. Below are the results of these field studies.

  17. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer.

    PubMed

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 +/- 118 mg kg(-1) dry sediment (n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg(-1)). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys.

  18. Characterization of anaerobic chloroethene-dehalogenating activity in several subsurface sediments

    SciTech Connect

    Skeen, R.S.; Gao, J.; Hooker, B.S.; Quesenberry, R.D.

    1996-11-01

    Anaerobic microcosms of subsurface soils from four locations were used to investigate the separate effects of several electron donors on tetrachloroethylene (PCE) dechlorination activity. The substrates tested were methanol, formate, lactate, acetate, and sucrose. Various levels of sulfate-reducing, acetogenic, fermentative, and methanogenic activity were observed in all sediments. PCE dechlorination was detected in all microcosms, but the amount of dehalogenation varied by several orders of magnitude. Trichloroethylene was the primary dehalogenation product; however, small amounts of cis-1,2-dichloroethylene, 1,1-dichloroethylene, and vinyl chloride were also detected in several microcosms. Lactate-amended microcosms showed large amounts of dehalogenation. in three of the four sediments. One of the two sediments which showed positive activity with lactate also had large amounts of delialogenation with methanol. Sucrose, formate, and acetate also stimulated large amounts of delialogenation in one sediment that showed activity with lactate. These results suggest that lactate may be an appropriate substrate for screening sediments for PCE or TCE delialogenation activity, but that the microbial response is not sufficient for complete in situ bioremediation. A detailed study of the Victoria activity revealed that delialogenation rates were more similar to the Cornell culture than to rates measured for methanogens, or a methanol-enriched sediment culture. This may suggest that these sediments contain a highly efficient delialogenation activity similar to the Cornell culture. This assertion is supported further by the fact that an average of 3% of added reducing equivalents could be diverted to dehalogenation in tests which were conducted using PCE-saturated hexadecane as a constant source of PCE during incubation. Further evidence is needed to confirm this premise. The application of these results to in situ bioremediation of highly contaminated areas are discussed.

  19. Sulfur and iron cycling in deep-subsurface, coal bed-containing sediments off Shimokita (Japan)

    NASA Astrophysics Data System (ADS)

    Riedinger, N.; Smirnoff, M. N.; Gilhooly, W.; Phillips, S. C.; Lyons, T. W.; 337 Scientific Party, I.

    2013-12-01

    The main goal of IODP Expedition 337 was the identification and characterization of the deep coal bed biosphere and hydrocarbon system off the Shimokita Peninsula (Japan) in the northwestern Pacific using the D/V Chikyu. To accomplish this scientific objective, it was also necessary to investigate the inorganic biogeochemistry in order to identify possible electron acceptors and bio-essential nutrients. These biogeochemical parameters greatly influence both, the composition and abundance of microbial communities as well as the organic carbon cycle. In turn, the microbially mediated carbon cycle influences the diagenetic reactions in the subsurface, thus, altering geochemical and physical characteristics of the material. Here we present results from metal and sulfur geochemical analyses from the deep-subsurface sediments (about 1250 to 2466 mbsf) at Site C0020 off Shimokita. The measured concentrations of acid volatile sulfur (AVS) as well as chromium reducible sulfur (CRS) reflect the alteration of iron oxides to iron sulfides and indicate that the main sulfur-bearing phase in the investigated sediments is pyrite. Concentrations of intermediate sulfur species are minor and occur mainly in the coal-bearing interval. Our data show that the uppermost sediments contain higher amounts of pyrite (up to 1.2 wt.%) with an average of 0.5 wt.% compared to the deeper deposits (below about 1800 mbsf), which show an average of 0.16 wt.%. In contrast, iron oxide concentrations are highest in the deeper sediment sections (up to 0.4%), where pyrite concentrations are low. The alteration of iron oxides to sulfides in theses lower section was probably governed by the amount of available sulfide in the pore water. The occurrence of (bio-)reactive iron phases in these deeply buried sediments has implications for the deep biosphere as those minerals have the potential to serve as electron acceptors during burial, including reactions involving deep sourced electron donors, such as

  20. Sorption of Cs+ to Micaceous Subsurface Sediments from the Hanford Site, USA

    SciTech Connect

    Zachara, John M.; Smith, Steven C.; Liu, Chongxuan; McKinley, James P.; Serne, R. Jeffrey; Gassman, Paul L.

    2002-01-15

    The sorption of Cs{sup +} was investigated over a large concentration range (10{sup -9}-10{sup -2} mol/L) on subsurface sediments from a United States nuclear materials site (Hanford) where high-level nuclear wastes (HLW) have been accidentally released to the vadose zone. The sediment sorbs large amounts of radiocesium, but expedited migration has been observed when HLW (a NaNO{sub 3} brine) is the carrier. Cs{sup +} sorption was measured on homoionic sediments (Na{sup +}, K{sup +}, Ca{sup 2+}) with electrolyte concentrations ranging from 0.01 to 1.0 mol/L. In Na{sup +} electrolyte, concentrations were extended to near saturation with NaNO{sub 3(s)} (7.0 mol/L). The sediment contained nonexpansible (biotite, muscovite) and expansible (vermiculite, smectite) phyllosilicates. The sorption data were interpreted according to the frayed edge-planar site conceptual model. A four-parameter, two-site (high- and low-affinity) numeric ion exchange model was effective in describing the sorption data. The high-affinity sites were ascribed to wedge zones on the micas where particle edges have partially expanded due to the removal of interlayer cations during weathering, and the low-affinity ones to planar sites on the expansible clays. The electrolyte cations competed with Cs{sup +} for both high- and low-affinity sites according to the trend K{sup +} >> Na{sup +} {ge} Ca{sup 2+}. At high salt concentration, Cs{sup +} adsorption occurred only on high-affinity sites. Na{sup +} was an effective competitor for the high-affinity sites at high salt concentrations. In select experiments, silver-thiourea (AgTU) was used as a blocking agent to further isolate and characterize the high-affinity sites, but the method was found to be problematic. Mica particles were handpicked from the sediment, contacted with Cs{sub eq}{sup +}, and analyzed by electron microprobe to identify phases and features important to Cs{sup +} sorption. The microprobe study implied that biotite was the primary

  1. Biosphere frontiers of subsurface life in the sedimented hydrothermal system of Guaymas Basin

    PubMed Central

    Teske, Andreas; Callaghan, Amy V.; LaRowe, Douglas E.

    2014-01-01

    Temperature is one of the key constraints on the spatial extent, physiological and phylogenetic diversity, and biogeochemical function of subsurface life. A model system to explore these interrelationships should offer a suitable range of geochemical regimes, carbon substrates and temperature gradients under which microbial life can generate energy and sustain itself. In this theory and hypothesis article, we make the case for the hydrothermally heated sediments of Guaymas Basin in the Gulf of California as a suitable model system where extensive temperature and geochemical gradients create distinct niches for active microbial populations in the hydrothermally influenced sedimentary subsurface that in turn intercept and process hydrothermally generated carbon sources. We synthesize the evidence for high-temperature microbial methane cycling and sulfate reduction at Guaymas Basin – with an eye on sulfate-dependent oxidation of abundant alkanes – and demonstrate the energetic feasibility of these latter types of deep subsurface life in previously drilled Guaymas Basin locations of Deep-Sea Drilling Project 64. PMID:25132832

  2. Ancient DNA complements microfossil record in deep-sea subsurface sediments.

    PubMed

    Lejzerowicz, Franck; Esling, Philippe; Majewski, Wojciech; Szczuciński, Witold; Decelle, Johan; Obadia, Cyril; Arbizu, Pedro Martinez; Pawlowski, Jan

    2013-08-23

    Deep-sea subsurface sediments are the most important archives of marine biodiversity. Until now, these archives were studied mainly using the microfossil record, disregarding large amounts of DNA accumulated on the deep-sea floor. Accessing ancient DNA (aDNA) molecules preserved down-core would offer unique insights into the history of marine biodiversity, including both fossilized and non-fossilized taxa. Here, we recover aDNA of eukaryotic origin across four cores collected at abyssal depths in the South Atlantic, in up to 32.5 thousand-year-old sediment layers. Our study focuses on Foraminifera and Radiolaria, two major groups of marine microfossils also comprising diverse non-fossilized taxa. We describe their assemblages in down-core sediment layers applying both micropalaeontological and environmental DNA sequencing approaches. Short fragments of the foraminiferal and radiolarian small subunit rRNA gene recovered from sedimentary DNA extracts provide evidence that eukaryotic aDNA is preserved in deep-sea sediments encompassing the last glacial maximum. Most aDNA were assigned to non-fossilized taxa that also dominate in molecular studies of modern environments. Our study reveals the potential of aDNA to better document the evolution of past marine ecosystems and opens new horizons for the development of deep-sea palaeogenomics.

  3. Diversity and community structure of archaea in deep subsurface sediments from the tropical Western pacific.

    PubMed

    Zhang, Wei; Saren, Gaowa; Li, Tiegang; Yu, Xinke; Zhang, Linbao

    2010-06-01

    Archaeal 16S rRNA gene clone libraries using PCR amplicons from eight different layers of the MD06-3051 core were obtained from the tropical Western Pacific sediments. A total of 768 clones were randomly selected, and 264 representative clones were sequenced by restriction fragment length polymorphism. Finally, 719 valid clones and 104 operational taxonomic units were identified after chimera-check and > or =97% similarity analysis. The phylogenetic analysis of 16S rDNA sequences obtained from sediment samples were very diverse and showed stratification with depth. Majority of the members were most closely related to uncultivated groups and physiologically uncharacterized assemblages. All phylotypes were affiliated with Crenarchaeota (76%) and Euryarchaeota (24%), respectively. Deep-sea archaeal group (DSAG, 41% of total clones) and miscellaneous crenarchaeotic group (MCG, 29% of total clones) belonging to Crenarchaeota were the most predominant archaeal 16S rDNA phylotypes in clone libraries. Phylotypes in this study shared high similarity with those in subsurface sediments from Peru Margin sites, which indicated that different geographical zones might host similar members of archaeal populations based on similar sedimentary environments. In our study, members of DSAG and MCG seemed to dominate certain layers of the nonhydrate sediments, suggesting a wide ecophysiological adaptation than previously appreciated. The spatial distribution and community structure of these groups might vary with the different geochemical gradients of the environment.

  4. Quantification of Microbial Communities in Subsurface Marine Sediments of the Black Sea and off Namibia

    PubMed Central

    Schippers, Axel; Kock, Dagmar; Höft, Carmen; Köweker, Gerrit; Siegert, Michael

    2011-01-01

    Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition – fluorescence in situ hybridization (CARD–FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased with depths from 109 to 1010 cells/mL at the sediment surface to 107–109 cells/mL below one meter depth. Based on CARD–FISH and Q-PCR analyses overall similar proportions of Bacteria and Archaea were found. The down-core distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes (16S and 18S rRNA) as well as functional genes involved in different biogeochemical processes was quantified using Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 as well as the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were highly abundant. Less abundant but detectable in most of the samples were Eukarya as well as the metal and sulfate-reducing Geobacteraceae (only in the Benguela upwelling influenced sediments). The functional genes cbbL, encoding for the large subunit of RuBisCO, the genes dsrA and aprA, indicative of sulfate-reducers as well as the mcrA gene of methanogens were detected in the Benguela upwelling and Black Sea sediments. Overall, the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea. PMID:22319518

  5. Methane in shallow subsurface sediments at the landward limit of the gas hydrate stability zone offshore western Svalbard

    NASA Astrophysics Data System (ADS)

    Graves, Carolyn A.; James, Rachael H.; Sapart, Célia Julia; Stott, Andrew W.; Wright, Ian C.; Berndt, Christian; Westbrook, Graham K.; Connelly, Douglas P.

    2017-02-01

    Offshore western Svalbard plumes of gas bubbles rise from the seafloor at the landward limit of the gas hydrate stability zone (LLGHSZ; ∼400 m water depth). It is hypothesized that this methane may, in part, come from dissociation of gas hydrate in the underlying sediments in response to recent warming of ocean bottom waters. To evaluate the potential role of gas hydrate in the supply of methane to the shallow subsurface sediments, and the role of anaerobic oxidation in regulating methane fluxes across the sediment-seawater interface, we have characterised the chemical and isotopic compositions of the gases and sediment pore waters. The molecular and isotopic signatures of gas in the bubble plumes (C1/C2+ = 1 × 104; δ13C-CH4 = -55 to -51‰; δD-CH4 = -187 to -184‰) are similar to gas hydrate recovered from within sediments ∼30 km away from the LLGHSZ. Modelling of pore water sulphate profiles indicates that subsurface methane fluxes are largely at steady state in the vicinity of the LLGHSZ, providing no evidence for any recent change in methane supply due to gas hydrate dissociation. However, at greater water depths, within the GHSZ, there is some evidence that the supply of methane to the shallow sediments has recently increased, which is consistent with downslope retreat of the GHSZ due to bottom water warming although other explanations are possible. We estimate that the upward diffusive methane flux into shallow subsurface sediments close to the LLGHSZ is 30,550 mmol m-2 yr-1, but it is <20 mmol m-2 yr-1 in sediments further away from the seafloor bubble plumes. While anaerobic oxidation within the sediments prevents significant transport of dissolved methane into ocean bottom waters this amounts to less than 10% of the total methane flux (dissolved + gas) into the shallow subsurface sediments, most of which escapes AOM as it is transported in the gas phase.

  6. Enumeration and characterization of iron(III)-reducing microbial communities from acidic subsurface sediments contaminated with uranium(VI).

    PubMed

    Petrie, Lainie; North, Nadia N; Dollhopf, Sherry L; Balkwill, David L; Kostka, Joel E

    2003-12-01

    Iron(III)-reducing bacteria have been demonstrated to rapidly catalyze the reduction and immobilization of uranium(VI) from contaminated subsurface sediments. Thus, these organisms may aid in the development of bioremediation strategies for uranium contamination, which is prevalent in acidic subsurface sediments at U.S. government facilities. Iron(III)-reducing enrichment cultures were initiated from pristine and contaminated (high in uranium, nitrate; low pH) subsurface sediments at pH 7 and pH 4 to 5. Enumeration of Fe(III)-reducing bacteria yielded cell counts of up to 240 cells ml(-1) for the contaminated and background sediments at both pHs with a range of different carbon sources (glycerol, acetate, lactate, and glucose). In enrichments where nitrate contamination was removed from the sediment by washing, MPN counts of Fe(III)-reducing bacteria increased substantially. Sediments of lower pH typically yielded lower counts of Fe(III)-reducing bacteria in lactate- and acetate-amended enrichments, but higher counts were observed when glucose was used as an electron donor in acidic enrichments. Phylogenetic analysis of 16S rRNA gene sequences extracted from the highest positive MPN dilutions revealed that the predominant members of Fe(III)-reducing consortia from background sediments were closely related to members of the Geobacteraceae family, whereas a recently characterized Fe(III) reducer (Anaeromyxobacter sp.) and organisms not previously shown to reduce Fe(III) (Paenibacillus and Brevibacillus spp.) predominated in the Fe(III)-reducing consortia of contaminated sediments. Analysis of enrichment cultures by terminal restriction fragment length polymorphism (T-RFLP) strongly supported the cloning and sequencing results. Dominant members of the Fe(III)-reducing consortia were observed to be stable over several enrichment culture transfers by T-RFLP in conjunction with measurements of Fe(III) reduction activity and carbon substrate utilization. Enrichment

  7. Enumeration and Characterization of Iron(III)-Reducing Microbial Communities from Acidic Subsurface Sediments Contaminated with Uranium(VI)

    PubMed Central

    Petrie, Lainie; North, Nadia N.; Dollhopf, Sherry L.; Balkwill, David L.; Kostka, Joel E.

    2003-01-01

    Iron(III)-reducing bacteria have been demonstrated to rapidly catalyze the reduction and immobilization of uranium(VI) from contaminated subsurface sediments. Thus, these organisms may aid in the development of bioremediation strategies for uranium contamination, which is prevalent in acidic subsurface sediments at U.S. government facilities. Iron(III)-reducing enrichment cultures were initiated from pristine and contaminated (high in uranium, nitrate; low pH) subsurface sediments at pH 7 and pH 4 to 5. Enumeration of Fe(III)-reducing bacteria yielded cell counts of up to 240 cells ml−1 for the contaminated and background sediments at both pHs with a range of different carbon sources (glycerol, acetate, lactate, and glucose). In enrichments where nitrate contamination was removed from the sediment by washing, MPN counts of Fe(III)-reducing bacteria increased substantially. Sediments of lower pH typically yielded lower counts of Fe(III)-reducing bacteria in lactate- and acetate-amended enrichments, but higher counts were observed when glucose was used as an electron donor in acidic enrichments. Phylogenetic analysis of 16S rRNA gene sequences extracted from the highest positive MPN dilutions revealed that the predominant members of Fe(III)-reducing consortia from background sediments were closely related to members of the Geobacteraceae family, whereas a recently characterized Fe(III) reducer (Anaeromyxobacter sp.) and organisms not previously shown to reduce Fe(III) (Paenibacillus and Brevibacillus spp.) predominated in the Fe(III)-reducing consortia of contaminated sediments. Analysis of enrichment cultures by terminal restriction fragment length polymorphism (T-RFLP) strongly supported the cloning and sequencing results. Dominant members of the Fe(III)-reducing consortia were observed to be stable over several enrichment culture transfers by T-RFLP in conjunction with measurements of Fe(III) reduction activity and carbon substrate utilization. Enrichment

  8. Microbial physiology-based model of ethanol metabolism in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Jin, Qusheng; Roden, Eric E.

    2011-07-01

    A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

  9. Final Report: Dominant Mechanisms of Uranium-Phosphate Reactions in Subsurface Sediments

    SciTech Connect

    Catalano, Jeffrey G.; Giammar, Daniel E.; Wang, Zheming

    2016-03-08

    Phosphate addition is an in situ remediation approach that may enhance the sequestration of uranium without requiring sustained reducing conditions. However, the geochemical factors that determine the dominant immobilization mechanisms upon phosphate addition are insufficiently understood to design efficient remediation strategies or accurately predict U(VI) transport. The overall objective of our project is to determine the dominant mechanisms of U(VI)-phosphate reactions in subsurface environments. Our research approach seeks to determine the U(VI)-phosphate solid that form in the presence of different groundwater cations, characterize the effects of phosphate on U(VI) adsorption and precipitation on smectite and iron oxide minerals, examples of two major reactive mineral phases in contaminated sediments, and investigate how phosphate affects U(VI) speciation and fate during water flow through sediments from contaminated sites. The research activities conducted for this project have generated a series of major findings. U(VI) phosphate solids from the autunite mineral family are the sole phases to form during precipitation, with uranyl orthophosphate not occurring despite its predicted greater stability. Calcium phosphates may take up substantial quantities of U(VI) through three different removal processes (adsorption, coprecipitation, and precipitation) but the dominance of each process varies with the pathway of reaction. Phosphate co-adsorbs with U(VI) onto smectite mineral surfaces, forming a mixed uranium-phosphate surface complex over a wide range of conditions. However, this molecular-scale association of uranium and phosphate has not effect on the overall extent of uptake. In contrast, phosphate enhanced U(VI) adsorption to iron oxide minerals at acidic pH conditions but suppresses such adsorption at neutral and alkaline pH, despite forming mixed uranium-phosphate surface complexes during adsorption. Nucleation barriers exist that inhibit U(VI) phosphate

  10. Influence of Acidic and Alkaline Waste Solution Properties on Uranium Migration in Subsurface Sediments

    SciTech Connect

    Szecsody, James E.; Truex, Michael J.; Qafoku, Nikolla; Wellman, Dawn M.; Resch, Charles T.; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments has significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2+, Mg2+) and phosphate and a slow (100s of hours) increase in silica, Al3+, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10s to 100s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  11. Fungal diversity from deep marine subsurface sediments (IODP 317, Canterbury Basin, New Zealand)

    NASA Astrophysics Data System (ADS)

    Redou, V.; Arzur, D.; Burgaud, G.; Barbier, G.

    2012-12-01

    Recent years have seen a growing interest regarding micro-eukaryotic communities in extreme environments as a third microbial domain after Bacteria and Archaea. However, knowledge is still scarce and the diversity of micro-eukaryotes in such environments remains hidden and their ecological role unknown. Our research program is based on the deep sedimentary layers of the Canterbury Basin in New Zealand (IODP 317) from the subsurface to the record depth of 1884 meters below seafloor. The objectives of our study are (i) to assess the genetic diversity of fungi in deep-sea sediments and (ii) identify the functional part in order to better understand the origin and the ecological role of fungal communities in this extreme ecosystem. Fingerprinting-based methods using capillary electrophoresis single-strand conformation polymorphism and denaturing high-performance liquid chromatography were used as a first step to raise our objectives. Molecular fungal diversity was assessed using amplification of ITS1 (Internal Transcribed Spacer 1) as a biomarker on 11 samples sediments from 3.76 to 1884 meters below seafloor. Fungal molecular signatures were detected throughout the sediment core. The phyla Ascomycota and Basidiomycota were revealed with DNA as well as cDNA. Most of the phylotypes are affiliated to environmental sequences and some to common fungal cultured species. The discovery of a present and metabolically active fungal component in this unique ecosystem allows some interesting first hypotheses that will be further combined to culture-based methods and deeper molecular methods (454 pyrosequencing) to highlight essential informations regarding physiology and ecological role of fungal communities in deep marine sediments.

  12. Geochemical and Mineralogical Investigation of Uranium in Multi–element Contaminated, Organic–rich Subsurface Sediment

    SciTech Connect

    Qafoku, Nikolla; Gartman, Brandy N.; Kukkadapu, Ravi K.; Arey, Bruce W.; Williams, Kenneth H.; Mouser, Paula J.; Heald, Steve M.; Bargar, John R.; Janot, Noemie; Yabusaki, Steven B.; Long, Philip E.

    2014-03-02

    Alluvial sediments characterized by an abundance of refractory or lignitic organic carbon compounds and reduced Fe and S bearing mineral phases have been identified through drilling activities at the U.S. Department of Energy’s (DOE) Integrated Field Research Challenge (IFRC) site at Rifle, CO. Regions of the subsurface from which such sediments are derived are referred to as Naturally Reduced Zones (NRZ). We conducted a study with NRZ sediments with the objective to: i.) Characterize solid phase contamination of U and other co-contaminants; ii.) Document the occurrence of potential U host minerals; iii.) Determine U valence state and micron scale spatial association with co-contaminants. Macroscopic (wet chemical batch extractions and a column experiment), microscopic (SEM-EDS), and spectroscopic (Mössbauer, µ-XRF and XANES) techniques were employed. Results showed that sediments’ solid phase had significant concentrations of U, S, As, Zn, V, Cr, Cu and Se, and a remarkable assortment of potential U hosts (sorbents and/or electron donors), such as Fe oxides (hematite, magnetite, Al-substituted goethite), siderite, reduced Fe(II) bearing clays, sulfides of different types, Zn sulfide framboids and multi – element sulfides. Multi-contaminants, micron size (ca. 5 to 30 µm) areas of mainly U(IV) and some U(VI), and/or other electron scavengers or donors such as Se, As, Cr, and V were discovered in the sediments, suggesting complex micron-scale system responses to transient redox conditions, and different extent and rates of competing U redox reactions than those of single contaminant systems. Collectively, the results improve our understanding and ability to predict U and NRZ’s complex behavior and will delineate future research directions to further study both the natural attenuation and persistence of contaminant plumes and their contribution to groundwater contamination.

  13. Influence of acidic and alkaline waste solution properties on uranium migration in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Szecsody, Jim E.; Truex, Mike J.; Qafoku, Nikolla P.; Wellman, Dawn M.; Resch, Tom; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments have significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100 s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2 +, Mg2 +) and phosphate and a slow (100 s of hours) increase in silica, Al3 +, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10 s to 100 s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in not only uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  14. Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

  15. ANME-2D Archaea Catalyze Methane Oxidation in Deep Subsurface Sediments Independent of Nitrate Reduction

    NASA Astrophysics Data System (ADS)

    Hernsdorf, A. W.; Amano, Y.; Suzuki, Y.; Ise, K.; Thomas, B. C.; Banfield, J. F.

    2015-12-01

    Terrestrial sediments are an important global reservoir for methane. Microorganisms in the deep subsurface play a critical role in the methane cycle, yet much remains to be learned about their diversity and metabolisms. To provide more comprehensive insight into the microbiology of the methane cycle in the deep subsurface, we conducted a genome-resolved study of samples collected from the Horonobe Underground Research Laboratory (HURL), Japan. Groundwater samples were obtained from three boreholes from a depth range of between 140 m and 250 m in two consecutive years. Groundwater was filtered and metagenomic DNA extracted and sequenced, and the sequence data assembled. Based on the sequences of phylogenetically informative genes on the assembled fragments, we detected a high degree of overlap in community composition across a vertical transect within one borehole at the two sampling times. However, there was comparatively little similarity observed among communities across boreholes. Spatial and temporal abundance patterns were used in combination with tetranucleotide signatures of assembled genome fragments to bin the data and reconstruct over 200 unique draft genomes, of which 137 are considered to be of high quality (>90% complete). The deepest samples from one borehole were highly dominated by an archaeon identified as ANME-2D; this organism was also present at lower abundance in all other samples from that borehole. Also abundant in these microbial communities were novel members of the Gammaproteobacteria, Saccharibacteria (TM7) and Tenericute phyla. Notably, a ~2 Mbp draft genome for the ANME-2D archaeon was reconstructed. As expected, the genome encodes all of the genes predicted to be involved in the reverse methanogenesis pathway. In contrast with the previously reported ANME2-D genome, the HURL ANME-2D genome lacks the capacity to reduce nitrate. However, we identified many multiheme cytochromes with closest similarity to those of the known Fe

  16. Change in bacterial community structure during in situ biostimulation of subsurface sediment cocontaminated with uranium and nitrate.

    PubMed

    North, Nadia N; Dollhopf, Sherry L; Petrie, Lainie; Istok, Jonathan D; Balkwill, David L; Kostka, Joel E

    2004-08-01

    Previous studies have demonstrated that metal-reducing microorganisms can effectively promote the precipitation and removal of uranium from contaminated groundwater. Microbial communities were stimulated in the acidic subsurface by pH neutralization and addition of an electron donor to wells. In single-well push-pull tests at a number of treated sites, nitrate, Fe(III), and uranium were extensively reduced and electron donors (glucose, ethanol) were consumed. Examination of sediment chemistry in cores sampled immediately adjacent to treated wells 3.5 months after treatment revealed that sediment pH increased substantially (by 1 to 2 pH units) while nitrate was largely depleted. A large diversity of 16S rRNA gene sequences were retrieved from subsurface sediments, including species from the alpha, beta, delta, and gamma subdivisions of the class Proteobacteria, as well as low- and high-G+C gram-positive species. Following in situ biostimulation of microbial communities within contaminated sediments, sequences related to previously cultured metal-reducing delta-Proteobacteria increased from 5% to nearly 40% of the clone libraries. Quantitative PCR revealed that Geobacter-type 16S rRNA gene sequences increased in biostimulated sediments by 1 to 2 orders of magnitude at two of the four sites tested. Evidence from the quantitative PCR analysis corroborated information obtained from 16S rRNA gene clone libraries, indicating that members of the delta-Proteobacteria subdivision, including Anaeromyxobacter dehalogenans-related and Geobacter-related sequences, are important metal-reducing organisms in acidic subsurface sediments. This study provides the first cultivation-independent analysis of the change in metal-reducing microbial communities in subsurface sediments during an in situ bioremediation experiment.

  17. Extracellular Enzymatic Hydrolysis of High Molecular Weight Organic Carbon in Eastern Mediterranean Sapropelic and Non-Sapropelic Subsurface Sediments

    NASA Astrophysics Data System (ADS)

    Hoarfrost, A.; Couper, L.; Arnosti, C.

    2014-12-01

    Organic carbon availability is an important constraint on microbial activity in the subsurface. Since most sedimentary organic matter is likely high molecular weight and complex, bioavailability of organic carbon is closely tied to activities of extracellular enzymes that hydrolyze organic macromolecules into transportable sizes. In part due to methodological difficulties, few measurements of extracellular enzymatic activities have been made in marine sediments below ca. 20cm depth. We measured extracellular hydrolysis of specific polysaccharides in deep sediments from sapropel and non-sapropel sections of a single core from the Eastern Mediterranean. In order to counteract adsorption of the substrate onto sediment particles, we developed an extraction protocol utilizing competitive desorption and mild heating. This treatment improved substrate recovery from incubation subsamples 5- to 10-fold, and enabled us to detect enzymatic activity in deep subsurface sediments. The wide variation in TOC between proximal sediment layers in this core provided an excellent opportunity to investigate (i) the rate at which subsurface microbial communities can hydrolyze a diversity of organic substrates, and (ii) rates and ranges of enzymatic capabilities as a function of sediment depth, organic carbon load and microbial community composition. Our experiments were carried out in long-term incubations (3-6 weeks), in which substrates were readily hydrolyzed, but hydrolysis rates differed among substrates and among sediment sections. Activity was not correlated with depth, but was highest in sections with highest organic carbon content. Isolation of strains able to grow directly on the substrates of interest are underway, and provide a promising path forward to illuminate mechanisms driving potential hydrolytic activity in the subsurface.

  18. Change in Bacterial Community Structure during In Situ Biostimulation of Subsurface Sediment Cocontaminated with Uranium and Nitrate

    PubMed Central

    North, Nadia N.; Dollhopf, Sherry L.; Petrie, Lainie; Istok, Jonathan D.; Balkwill, David L.; Kostka, Joel E.

    2004-01-01

    Previous studies have demonstrated that metal-reducing microorganisms can effectively promote the precipitation and removal of uranium from contaminated groundwater. Microbial communities were stimulated in the acidic subsurface by pH neutralization and addition of an electron donor to wells. In single-well push-pull tests at a number of treated sites, nitrate, Fe(III), and uranium were extensively reduced and electron donors (glucose, ethanol) were consumed. Examination of sediment chemistry in cores sampled immediately adjacent to treated wells 3.5 months after treatment revealed that sediment pH increased substantially (by 1 to 2 pH units) while nitrate was largely depleted. A large diversity of 16S rRNA gene sequences were retrieved from subsurface sediments, including species from the α, β, δ, and γ subdivisions of the class Proteobacteria, as well as low- and high-G+C gram-positive species. Following in situ biostimulation of microbial communities within contaminated sediments, sequences related to previously cultured metal-reducing δ-Proteobacteria increased from 5% to nearly 40% of the clone libraries. Quantitative PCR revealed that Geobacter-type 16S rRNA gene sequences increased in biostimulated sediments by 1 to 2 orders of magnitude at two of the four sites tested. Evidence from the quantitative PCR analysis corroborated information obtained from 16S rRNA gene clone libraries, indicating that members of the δ-Proteobacteria subdivision, including Anaeromyxobacter dehalogenans-related and Geobacter-related sequences, are important metal-reducing organisms in acidic subsurface sediments. This study provides the first cultivation-independent analysis of the change in metal-reducing microbial communities in subsurface sediments during an in situ bioremediation experiment. PMID:15294831

  19. Isolation and characterization of RNA from low-biomass deep-subsurface sediments.

    PubMed Central

    Ogram, A; Sun, W; Brockman, F J; Fredrickson, J K

    1995-01-01

    Three methods for the isolation of microbial RNA from low-biomass deep-subsurface sediments have been developed and evaluated. RNA was isolated from samples taken from depths ranging from 173 to 217 m, and samples represented a variety of lithologies, including lacustrine, fluvial sand, and paleosol sediments. Cell numbers in these samples were estimated to be between log 4.0 and log 5.1/g on the basis of phospholipid fatty acid analysis. The most efficient method examined is based on the direct lysis of microbial cells followed by the extraction of RNA with alkaline phosphate buffers and subsequent inactivation of nucleases by extraction with guanidinium isothiocyanate. Estimated recoveries of mRNA for this method are approximately 26%. The recovered RNA included both mRNA and rRNA, as evidenced by the detection of sequences homologous to transcripts from the toluene-4-monooxygenase gene of Pseudomonas mendocina KR1 and bacterial, archaeal, and eukaryotic rRNA. An unexpectedly high relative concentration of archaeal rRNA (22 to 40%) was observed for these samples. PMID:7574612

  20. Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

    DOEpatents

    Kansa, Edward J.; Wijesinghe, Ananda M.; Viani, Brian E.

    1997-01-01

    The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculents and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude.

  1. Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

    DOEpatents

    Kansa, E.J.; Wijesinghe, A.M.; Viani, B.E.

    1997-01-14

    The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculants and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude. 8 figs.

  2. Use of sediment source fingerprinting to assess the role of subsurface erosion in the supply of fine sediment in a degraded catchment in the Eastern Cape, South Africa.

    PubMed

    Manjoro, Munyaradzi; Rowntree, Kate; Kakembo, Vincent; Foster, Ian; Collins, Adrian L

    2016-08-04

    Sediment source fingerprinting has been successfully deployed to provide information on the surface and subsurface sources of sediment in many catchments around the world. However, there is still scope to re-examine some of the major assumptions of the technique with reference to the number of fingerprint properties used in the model, the number of model iterations and the potential uncertainties of using more than one sediment core collected from the same floodplain sink. We investigated the role of subsurface erosion in the supply of fine sediment to two sediment cores collected from a floodplain in a small degraded catchment in the Eastern Cape, South Africa. The results showed that increasing the number of individual fingerprint properties in the composite signature did not improve the model goodness-of-fit. This is still a much debated issue in sediment source fingerprinting. To test the goodness-of-fit further, the number of model repeat iterations was increased from 5000 to 30,000. However, this did not reduce uncertainty ranges in modelled source proportions nor improve the model goodness-of-fit. The estimated sediment source contributions were not consistent with the available published data on erosion processes in the study catchment. The temporal pattern of sediment source contributions predicted for the two sediment cores was very different despite the cores being collected in close proximity from the same floodplain. This highlights some of the potential limitations associated with using floodplain cores to reconstruct catchment erosion processes and associated sediment source contributions. For the source tracing approach in general, the findings here suggest the need for further investigations into uncertainties related to the number of fingerprint properties included in un-mixing models. The findings support the current widespread use of ≤5000 model repeat iterations for estimating the key sources of sediment samples.

  3. Final report - Reduction of mercury in saturated subsurface sediments and its potential to mobilize mercury in its elemental form

    SciTech Connect

    Bakray, Tamar

    2013-06-13

    The goal of our project was to investigate Hg(II) reduction in the deep subsurface. We focused on microbial and abiotic pathways of reduction and explored how it affected the toxicity and mobility of Hg in this unique environment. The project’s tasks included: 1. Examining the role of mer activities in the reduction of Hg(II) in denitrifying enrichment cultures; 2. Investigating the biotic/abiotic reduction of Hg(II) under iron reducing conditions; 3. Examining Hg(II) redox transformations under anaerobic conditions in subsurface sediments from DOE sites.

  4. Phylogenetic and functional diversity of microbial communities associated with subsurface sediments of the Sonora Margin, Guaymas Basin.

    PubMed

    Vigneron, Adrien; Cruaud, Perrine; Roussel, Erwan G; Pignet, Patricia; Caprais, Jean-Claude; Callac, Nolwenn; Ciobanu, Maria-Cristina; Godfroy, Anne; Cragg, Barry A; Parkes, John R; Van Nostrand, Joy D; He, Zhili; Zhou, Jizhong; Toffin, Laurent

    2014-01-01

    Subsurface sediments of the Sonora Margin (Guaymas Basin), located in proximity of active cold seep sites were explored. The taxonomic and functional diversity of bacterial and archaeal communities were investigated from 1 to 10 meters below the seafloor. Microbial community structure and abundance and distribution of dominant populations were assessed using complementary molecular approaches (Ribosomal Intergenic Spacer Analysis, 16S rRNA libraries and quantitative PCR with an extensive primers set) and correlated to comprehensive geochemical data. Moreover the metabolic potentials and functional traits of the microbial community were also identified using the GeoChip functional gene microarray and metabolic rates. The active microbial community structure in the Sonora Margin sediments was related to deep subsurface ecosystems (Marine Benthic Groups B and D, Miscellaneous Crenarchaeotal Group, Chloroflexi and Candidate divisions) and remained relatively similar throughout the sediment section, despite defined biogeochemical gradients. However, relative abundances of bacterial and archaeal dominant lineages were significantly correlated with organic carbon quantity and origin. Consistently, metabolic pathways for the degradation and assimilation of this organic carbon as well as genetic potentials for the transformation of detrital organic matters, hydrocarbons and recalcitrant substrates were detected, suggesting that chemoorganotrophic microorganisms may dominate the microbial community of the Sonora Margin subsurface sediments.

  5. The role of nanopores on U(VI) sorption and redox behavior in U(VI)-contaminated subsurface sediments

    SciTech Connect

    Xu, Huifang; Roden, Eric E.; Kemner, Kenneth M.; Jung, Hun-Bok; Konishi, Hiromi; Boyanov, Maxim; Sun, Yubing; Mishra, Bhoopesh

    2013-10-16

    Most reactive surfaces in clay-dominated sediments are present within nanopores (pores of nm dimension). The behavior of geological fluids and minerals in nanopores is significantly different from those in normal non-nanoporous environments. The effect of nanopore surfaces on U(VI) sorption/desorption and reduction is likely to be significant in clay-rich subsurface environments. Our research results from both model nanopore system and natural sediments from both model system (synthetic nanopore alumina) and sediments from the ORNL Field Research Center prove that U(VI) sorption on nanopore surfaces can be greatly enhanced by nanopore confinement environments. The results from the project provide advanced mechanistic, quantitative information on the physiochemical controls on uranium sorption and redox behavior in subsurface sediments. The influence of nanopore surfaces on coupled uranium sorption/desorption and reduction processes is significant in virtually all subsurface environments, because most reactive surfaces are in fact nanopore surfaces. The results will enhance transfer of our laboratory-based research to a major field research initiative where reductive uranium immobilization is being investigated. Our results will also provide the basic science for developing in-situ colloidal barrier of nanoporous alumina in support of environmental remediation and long term stewardship of DOE sites.

  6. Phylogenetic and Functional Diversity of Microbial Communities Associated with Subsurface Sediments of the Sonora Margin, Guaymas Basin

    PubMed Central

    Vigneron, Adrien; Cruaud, Perrine; Roussel, Erwan G.; Pignet, Patricia; Caprais, Jean-Claude; Callac, Nolwenn; Ciobanu, Maria-Cristina; Godfroy, Anne; Cragg, Barry A.; Parkes, John R.; Van Nostrand, Joy D.; He, Zhili; Zhou, Jizhong; Toffin, Laurent

    2014-01-01

    Subsurface sediments of the Sonora Margin (Guaymas Basin), located in proximity of active cold seep sites were explored. The taxonomic and functional diversity of bacterial and archaeal communities were investigated from 1 to 10 meters below the seafloor. Microbial community structure and abundance and distribution of dominant populations were assessed using complementary molecular approaches (Ribosomal Intergenic Spacer Analysis, 16S rRNA libraries and quantitative PCR with an extensive primers set) and correlated to comprehensive geochemical data. Moreover the metabolic potentials and functional traits of the microbial community were also identified using the GeoChip functional gene microarray and metabolic rates. The active microbial community structure in the Sonora Margin sediments was related to deep subsurface ecosystems (Marine Benthic Groups B and D, Miscellaneous Crenarchaeotal Group, Chloroflexi and Candidate divisions) and remained relatively similar throughout the sediment section, despite defined biogeochemical gradients. However, relative abundances of bacterial and archaeal dominant lineages were significantly correlated with organic carbon quantity and origin. Consistently, metabolic pathways for the degradation and assimilation of this organic carbon as well as genetic potentials for the transformation of detrital organic matters, hydrocarbons and recalcitrant substrates were detected, suggesting that chemoorganotrophic microorganisms may dominate the microbial community of the Sonora Margin subsurface sediments. PMID:25099369

  7. Microbial Communities and Organic Matter Composition in Surface and Subsurface Sediments of the Helgoland Mud Area, North Sea

    PubMed Central

    Oni, Oluwatobi E.; Schmidt, Frauke; Miyatake, Tetsuro; Kasten, Sabine; Witt, Matthias; Hinrichs, Kai-Uwe; Friedrich, Michael W.

    2015-01-01

    The role of microorganisms in the cycling of sedimentary organic carbon is a crucial one. To better understand relationships between molecular composition of a potentially bioavailable fraction of organic matter and microbial populations, bacterial and archaeal communities were characterized using pyrosequencing-based 16S rRNA gene analysis in surface (top 30 cm) and subsurface/deeper sediments (30–530 cm) of the Helgoland mud area, North Sea. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) was used to characterize a potentially bioavailable organic matter fraction (hot-water extractable organic matter, WE-OM). Algal polymer-associated microbial populations such as members of the Gammaproteobacteria, Bacteroidetes, and Verrucomicrobia were dominant in surface sediments while members of the Chloroflexi (Dehalococcoidales and candidate order GIF9) and Miscellaneous Crenarchaeota Groups (MCG), both of which are linked to degradation of more recalcitrant, aromatic compounds and detrital proteins, were dominant in subsurface sediments. Microbial populations dominant in subsurface sediments (Chloroflexi, members of MCG, and Thermoplasmata) showed strong correlations to total organic carbon (TOC) content. Changes of WE-OM with sediment depth reveal molecular transformations from oxygen-rich [high oxygen to carbon (O/C), low hydrogen to carbon (H/C) ratios] aromatic compounds and highly unsaturated compounds toward compounds with lower O/C and higher H/C ratios. The observed molecular changes were most pronounced in organic compounds containing only CHO atoms. Our data thus, highlights classes of sedimentary organic compounds that may serve as microbial energy sources in methanic marine subsurface environments. PMID:26635758

  8. Fossilized intact polar lipids of photosynthetic organisms in ancient subsurface sediments

    NASA Astrophysics Data System (ADS)

    Bauersachs, T.; Schouten, S.; Hopmans, E. C.; Sinninghe Damsté, J. S.

    2009-12-01

    In recent years, the idea of a rich microbial biosphere in the marine sea floor has been widely accepted. This so-called “deep biosphere” is estimated to contain ca. 50 % of Earth’s total prokaryotic biomass with the overall order of magnitude of microbial cells in the sea floor being the same as the biomass of all surface plant life (Whitman et al. 1998). Evidence for the existence of a deep biosphere comes, among others, from the analysis of intact polar lipids (IPLs). This approach presumes that IPLs almost instantaneously lose their polar head group after cell death and thus do not preserve on geological timescales. Consequently, IPLs in the subsurface should derive from in situ production and hence indicate the presence of living prokaryotic cells. For example, in various oceanic subsurface sediments archaeal IPLs have been found, suggesting that Archaea constitute a major fraction of the deep biosphere biomass (Lipp et al. 2008). In this study, we found IPLs of heterocystous cyanobacteria in a number of ancient and deeply buried sediments. Heterocystous cyanobacteria are strictly photoautotrophic organisms that are a common constituent of the phytoplankton community in many freshwater and brackish environments but are also encountered in the marine realm as endosymbionts of diatom species. Under nitrogen-depleted conditions, these organisms carry out nitrogen fixation in specialized cells, known as heterocysts. These cells contain a suite of heterocyst glycolipids (HGs) that have not been identified in any other organism and are thus unique biological markers for nitrogen-fixing heterocystous cyanobacteria. Using high performance liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (HPLC/ESI-MS/MS), we detected HGs in Pleistocene and Pliocene Mediterranean sapropels buried up to 60 m below the seafloor. In addition, these HGs were also found in lacustrine deposits of the Oligocene Lake Enspel (35 Ma), the Eocene Lake Messel

  9. Distribution of Microbial Biomass and Potential for Anaerobic Respiration in Hanford Site 300 Area Subsurface Sediment

    PubMed Central

    Lin, Xueju; Kennedy, David; Peacock, Aaron; McKinley, James; Resch, Charles T.; Fredrickson, James

    2012-01-01

    Subsurface sediments were recovered from a 52-m-deep borehole cored in the 300 Area of the Hanford Site in southeastern Washington State to assess the potential for biogeochemical transformation of radionuclide contaminants. Microbial analyses were made on 17 sediment samples traversing multiple geological units: the oxic coarse-grained Hanford formation (9 to 17.4 m), the oxic fine-grained upper Ringold formation (17.7 to 18.1 m), and the reduced Ringold formation (18.3 to 52 m). Microbial biomass (measured as phospholipid fatty acids) ranged from 7 to 974 pmols per g in discrete samples, with the highest numbers found in the Hanford formation. On average, strata below 17.4 m had 13-fold less biomass than those from shallower strata. The nosZ gene that encodes nitrous oxide reductase (measured by quantitative real-time PCR) had an abundance of 5 to 17 relative to that of total 16S rRNA genes below 18.3 m and <5 above 18.1 m. Most nosZ sequences were affiliated with Ochrobactrum anthropi (97 sequence similarity) or had a nearest neighbor of Achromobacter xylosoxidans (90 similarity). Passive multilevel sampling of groundwater geochemistry demonstrated a redox gradient in the 1.5-m region between the Hanford-Ringold formation contact and the Ringold oxic-anoxic interface. Within this zone, copies of the dsrA gene and Geobacteraceae had the highest relative abundance. The majority of dsrA genes detected near the interface were related to Desulfotomaculum spp. These analyses indicate that the region just below the contact between the Hanford and Ringold formations is a zone of active biogeochemical redox cycling. PMID:22138990

  10. Archaea in Organic-Lean and Organic-Rich Marine Subsurface Sediments: An Environmental Gradient Reflected in Distinct Phylogenetic Lineages

    PubMed Central

    Durbin, Alan M.; Teske, Andreas

    2012-01-01

    Examining the patterns of archaeal diversity in little-explored organic-lean marine subsurface sediments presents an opportunity to study the association of phylogenetic affiliation and habitat preference in uncultured marine Archaea. Here we have compiled and re-analyzed published archaeal 16S rRNA clone library datasets across a spectrum of sediment trophic states characterized by a wide range of terminal electron-accepting processes. Our results show that organic-lean marine sediments in deep marine basins and oligotrophic open ocean locations are inhabited by distinct lineages of archaea that are not found in the more frequently studied, organic-rich continental margin sediments. We hypothesize that different combinations of electron donor and acceptor concentrations along the organic-rich/organic-lean spectrum result in distinct archaeal communities, and propose an integrated classification of habitat characteristics and archaeal community structure. PMID:22666218

  11. Impact of paleoclimate on the distribution of microbial communities in the subsurface sediment of the Dead Sea.

    PubMed

    Thomas, C; Ionescu, D; Ariztegui, D

    2015-11-01

    A long sedimentary core has been recently retrieved from the Dead Sea Basin (DSB) within the framework of the ICDP-sponsored Dead Sea Deep Drilling Project. Contrasting climatic intervals were evident by distinctive lithological facies such as laminated aragonitic muds and evaporites. A geomicrobiological investigation was conducted in representative sediments of this core. To identify the microbial assemblages present in the sediments and their evolution with changing depositional environments through time, the diversity of the 16S rRNA gene was analyzed in gypsum, aragonitic laminae, and halite samples. The subsurface microbial community was largely dominated by the Euryarchaeota phylum (Archaea). Within the latter, Halobacteriaceae members were ubiquitous, probably favored by their 'high salt-in' osmotic adaptation which also makes them one of the rare inhabitants of the modern Dead Sea. Bacterial community members were scarce, emphasizing that the 'low salt-in' strategy is less suitable in this environment. Substantial differences in assemblages are observed between aragonitic sediments and gypsum-halite ones, independently of the depth and salinity. The aragonite sample, deposited during humid periods when the lake was stratified, consists mostly of the archaeal MSBL1 and bacterial KB1 Candidate Divisions. This consortium probably relies on compatible solutes supplied from the lake by halotolerant species present in these more favorable periods. In contrast, members of the Halobacteriaceae were the sole habitants of the gypsum-halite sediments which result from a holomictic lake. Although the biomass is low, these variations in the observed subsurface microbial populations appear to be controlled by biological conditions in the water column at the time of sedimentation, and subsequently by the presence or absence of stratification and dilution in the lake. As the latter are controlled by climatic changes, our data suggest a relationship between local

  12. Analysis of a PAH-degrading bacterial population in subsurface sediments on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Shao, Zongze; Cui, Zhisong; Dong, Chunming; Lai, Qiliang; Chen, Liang

    2010-05-01

    Little is known about the types and concentrations of polycyclic aromatic hydrocarbons (PAHs) existing in the deep-sea subsurface environment, which is believed to be cold, oligothrophic and of high static pressure. PAHs in the upper layers of the water column are unavoidably subjected to degradation while they are deposited to the sea floor and become embedded in the deep-sea sediment. In this report, a high concentration of PAHs was discovered in the sediment 2.7 m beneath the bottom surface at a water depth of 3962 m on the Mid-Atlantic Ridge (MAR). The total concentration of PAHs was 445 ng (g dry wt sediment) -1. Among the seven detected PAHs, the concentrations of phenanthrene (222 ng g -1) and fluorene (79 ng g -1) were relatively high. In addition, PAH-degrading bacteria were found within the sediments. As in a previously detected site on the MAR, in the PAH-enriched region of this site, a bacterium of the genus Cycloclasticus was found to be the predominant isolate detected by PCR-DGGE analysis. In addition, bacteria of the Halomonas, Marinobacter, Alcanivorax, Thalassospira and Maricaulis genera, were also included in the PAH-degrading community. In summary, a high concentration of PAHs was detected in the subsurface of the deep-sea sediment, and once again, the Cycloclasticus bacterium was confirmed to be a ubiquitous marine PAH degrader even in the subsurface marine environment. Considering the abundance of PAHs therein, biodegradation is thus thought to be inactive, probably because of the low temperature, limited oxygen and/or limited nutrients.

  13. Isolation and Characterization of Gram-Positive Piezophilic Bacteria from Deep Marine Subsurface Sediment

    NASA Astrophysics Data System (ADS)

    Runko, G. M.; Fang, J.; Kato, C.

    2014-12-01

    The marine deep biosphere remains as the least studied of all of Earth's habitats and is inadequately understood, but is extremely important to understand the impacts that microbes have on global biogeochemical cycles. Sediment samples were obtained during IODP Expedition 337 in the western Pacific Ocean, from 1,498 meters below the seafloor (mbsf; samples 6R3), 1,951-1,999 mbsf (19R1), and 2,406 mbsf (29R7). These samples were initially mixed with marine broth and cultivated under anaerobic conditions at pressure of 35 MPa (megapascal) and temperatures of 35° C, 45° C, and 55° C for 3 months on board the Chikyu. Single colonies were isolated via plating on marine broth. Then, six strains of bacteria were identified, 6R3-1, 6R3-15, 19R1-5, 29R7-12B, 29R7-12M, and 29R7-12S. The six strains were then examined for optimal growth temperature and pressure. These organisms are Gram-positive, spore-forming, facultative anaerobic piezophilic bacteria. Major fatty acids are anteiso-15:0, anteiso-17:0 and iso-15:0. Phylogenetic analysis of 16S rRNA gene sequences revealed that the isolates are closely related to Virgibacillus pantothenticus, Robinsoniella peoriensis, and Bacillus subtilis. Because of their abundance in the deep marine subsurface, these microorganisms likely play an important role in sustaining the deep microbial ecosystem and influencing biogeochemical cycles in the deep biosphere.

  14. Boosting subsurface life: is subseafloor sediment a natural catalyst for radiolytic hydrogen production?

    NASA Astrophysics Data System (ADS)

    Sauvage, J.; Graham, D.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; D'Hondt, S.

    2014-12-01

    Naturally occurring production of molecular hydrogen (H2) by water radiolysis may be a fundamentally important source of electron donors (energy) for life in subsurface environments where organic matter is scarce. Previous studies with very high gamma radiation rates and wet mineral phases have reported high H2 production relative to production from water radiolysis in the absence of solid phases. Numerical calculations by other previous studies have predicted enhanced H2 production from seawater radiolysis relative to pure water radiolysis, due to the interaction of anions with hydroxyl radicals. Given these reports, the potential catalytic influences of solid and dissolved chemical phases on radiolytic H2 production need to be carefully quantified in order to fully evaluate the role of radiolytic H2 as a microbial energy source. For such quantification, we undertook gamma-irradiation experiments with pure water, deep ocean water and mixtures (slurries, φ = 0.85) of seawater with: North Pacific abyssal clay and calcareous oozes, coastal sediment, zirconium dioxide, and zeolite. We carried out our experiments at the Rhode Island Nuclear Science Center using a 37Cesium source at low dose rates (up to 0.1 Gy/hr). Our results to date include the following. First, the per-dose radiolytic H2 yield of pure water at low dose rates is directly comparable to the per-dose yield at much higher dose rates (ca. 1 kGy/hr); this result indicates that H2 production rate is linearly related to radiation dose rate across four orders of magnitude. Second, there is no statistically significant difference (90% confidence limit) between the radiolytic H2 yield from pure water and that from seawater; this result rules out influence of abundant seawater salts on H2 yield from water radiolysis. Third, H2 production from a mixture of abyssal clay and seawater is 25% higher than the yield from pure water. This enhanced yield is consistent with catalysis of radiolytic H2 production by

  15. Characterization of the intragranular water regime within subsurface sediments: pore volume, surface area, and mass transfer limitations

    USGS Publications Warehouse

    Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

    2011-01-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ~1% of the solid volume and intragranular surface areas of ~20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.

  16. Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations

    USGS Publications Warehouse

    Hay, M.B.; Stoliker, D.L.; Davis, J.A.; Zachara, J.M.

    2011-01-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ???1% of the solid volume and intragranular surface areas of ???20%-35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity. Copyright 2011 by the American Geophysical Union.

  17. Stetson Pit, Dare County, North Carolina: An integrated chronologic, faunal, and floral record of subsurface coastal quaternary sediments

    USGS Publications Warehouse

    York, L.L.; Wehmiller, J. F.; Cronin, T. M.; Ager, T.A.

    1989-01-01

    Continuous split spoon samples from a drill hole penetrating 34 m of coastal plain sediments at Stetson Pit in Dare County, North Carolina were taken for lithologic, aminostratigraphic, faunal (ostracodes) and floral (pollen) analyses. Three distinct aminozones are recognized in the subsurface section based upon D-alloisoleucine/L-isoleucine (A/I) values in each of the molluscan species Mulinia lateralis and Mercenaria sp. Ostracode zonations in the subsurface section are based on percentages of 80 thermophilic and cryophilic species (those living today south and north of Cape Hatteras) and the percentages of brackish water species. Five assemblage zones are delineated. Six pollen assemblage zones are also delineated within the subsurface section based upon study of 48 sediment samples. The subsurface record at Stetson Pit is interpreted to represent portions of four interglacials based upon the combined faunal, floral and aminostratigraphic data. The two younger aminozones, with amino acid age estimates of 100,000??20,000 yr (-7.2 to -11.2 m MSL) and 300,000-500,000 yr (-13 to -14.2 m MSL), represent portions of middle/late Pleistocene interglacials. The lower aminozone (-17.4 to -33 m MSL) spans an interval that probably includes at least two interglacials (based upon faunal and floral records) and has an age estimated to be between 800,000 and 1,300,000 yr. Boundaries delineated by faunal, floral, and amino acid methods do not always coincide, due to sampling constraints and phase lags between the different records. One major unconformity (at -17.4 m MSL) in the Stetson Pit section is easily recognized from lithologic characteristics and may represent a hiatus of as much as 800,000 yr. Lithologic changes associated with all other zone boundaries are subtle and would probably not be considered significant in the absence of faunal, floral, or amino acid data. ?? 1989.

  18. Diversity of prokaryotes and methanogenesis in deep subsurface sediments from the Nankai Trough, Ocean Drilling Program Leg 190.

    PubMed

    Newberry, Carole J; Webster, Gordon; Cragg, Barry A; Parkes, R John; Weightman, Andrew J; Fry, John C

    2004-03-01

    Diversity of Bacteria and Archaea was studied in deep marine sediments by PCR amplification and sequence analysis of 16S rRNA and methyl co-enzyme M reductase (mcrA) genes. Samples analysed were from Ocean Drilling Program (ODP) Leg 190 deep subsurface sediments at three sites spanning the Nankai Trough in the Pacific Ocean off Shikoku Island, Japan. DNA was amplified, from three depths at site 1173 (4.15, 98.29 and 193.29 mbsf; metres below the sea floor), and phylogenetic analysis of clone libraries showed a wide variety of uncultured Bacteria and Archaea. Sequences of Bacteria were dominated by an uncultured and deeply branching 'deep sediment group' (53% of sequences). Archaeal 16S rRNA gene sequences were mainly within the uncultured clades of the Crenarchaeota. There was good agreement between sequences obtained independently by cloning and by denaturing gradient gel electrophoresis. These sequences were similar to others retrieved from marine sediment and other anoxic habitats, and so probably represent important indigenous bacteria. The mcrA gene analysis suggested limited methanogen diversity with only three gene clusters identified within the Methanosarcinales and Methanobacteriales. The cultivated members of the Methanobacteriales and some of the Methanosarcinales can use CO2 and H2 for methanogenesis. These substrates also gave the highest rates in 14C-radiotracer estimates of methanogenic activity, with rates comparable to those from other deep marine sediments. Thus, this research demonstrates the importance of the 'deep sediment group' of uncultured Bacteria and links limited diversity of methanogens to the dominance of CO2/H2 based methanogenesis in deep sub-seafloor sediments.

  19. Isotopic identification of the source of methane in subsurface sediments of an area surrounded by waste disposal facilities

    USGS Publications Warehouse

    Hackley, Keith C.; Liu, Chao-Li; Trainor, D.

    1999-01-01

    The major source of methane (CH4) in subsurface sediments on the property of a former hazardous waste treatment facility was determined using isotopic analyses measured on CH4 and associated groundwater. The site, located on an earthen pier built into a shallow wetland lake, has had a history of waste disposal practices and is surrounded by landfills and other waste management facilities. Concentrations of CH4 up to 70% were found in the headspace gases of several piezometers screened at 3 different depths (ranging from 8 to 17 m) in lacustrine and glacial till deposits. Possible sources of the CH4 included a nearby landfill, organic wastes from previous impoundments and microbial gas derived from natural organic matter in the sediments. Isotopic analyses included ??13C, ??D, 14C, and 3H on select CH4 samples and ??D and ??18O on groundwater samples. Methane from the deepest glacial till and intermediate lacustrine deposits had ??13C values from -79 to -82???, typical of natural 'drift gas' generated by microbial CO2-reduction. The CH4 from the shallow lacustrine deposits had ??13C values from -63 to -76???, interpreted as a mixture between CH4 generated by microbial fermentation and the CO2-reduction processes within the subsurface sediments. The ??D values of all the CH4 samples were quite negative ranging from -272 to -299???. Groundwater sampled from the deeper zones also showed quite negative ??D values that explained the light ??D observed for the CH4. Radiocarbon analyses of the CH4 showed decreasing 14C activity with depth, from a high of 58 pMC in the shallow sediments to 2 pMC in the deeper glacial till. The isotopic data indicated the majority of CH4 detected in the fill deposits of this site was microbial CH4 generated from naturally buried organic matter within the subsurface sediments. However, the isotopic data of CH4 from the shallow piezometers was more variable and the possibility of some mixing with oxidized landfill CH4 could not be completely

  20. Metagenomics of the subsurface Brazos-Trinity Basin (IODP site 1320): comparison with other sediment and pyrosequenced metagenomes.

    PubMed

    Biddle, Jennifer F; White, James Robert; Teske, Andreas P; House, Christopher H

    2011-06-01

    The Brazos-Trinity Basin on the slope of the Gulf of Mexico passive margin was drilled during Integrated Ocean Drilling Progam Expedition 308. The buried anaerobic sediments of this basin are largely organic-poor and have few microbial inhabitants compared with the organic-rich sediments with high cell counts from the Peru Margin that were drilled during Ocean Drilling Program Leg 201. Nucleic acids were extracted from Brazos-Trinity Basin sediments and were subjected to whole-genome amplification and pyrosequencing. A comparison of the Brazos-Trinity Basin metagenome, consisting of 105 Mbp, and the existing Peru Margin metagenome revealed trends linking gene content, phylogenetic content, geological location and geochemical regime. The major microbial groups (Proteobacteria, Firmicutes, Euryarchaeota and Chloroflexi) occur consistently throughout all samples, yet their shifting abundances allow for discrimination between samples. The cluster of orthologous groups category abundances for some classes of genes are correlated with geochemical factors, such as the level of ammonia. Here we describe the sediment metagenome from the oligotrophic Brazos-Trinity Basin (Site 1320) and show similarities and differences with the dataset from the Pacific Peru Margin (Site 1229) and other pyrosequenced datasets. The microbial community found at Integrated Ocean Drilling Program Site 1320 likely represents the subsurface microbial inhabitants of turbiditic slopes that lack substantial upwelling.

  1. Effect of surface inlet type on suspended sediment transported through a subsurface drain tile system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Throughout the Prairie Pothole Region, subsurface tile and surface inlets are used to remove water from low-lying or poorly-drained soils. Open inlets are being increasingly converted to buried inlets in which perforated tile is placed in a trench of rock (i.e., a French drain) and buried below a la...

  2. PROTOZOA IN SUBSURFACE SEDIMENTS FROM SITE CONTAMI- NATED WITH AVIATION GASOLINE OR JET FUEL

    EPA Science Inventory

    Numbers of protozoa in the subsurface of aviation gasoline and jet fuel spill areas at a Coast Guard base at Traverse City, Mich., were determined. Boreholes were drilled in an uncontaminated location, in contaminated but untreated parts of the fuel plumes, and in the aviation ga...

  3. Morphologic evidence of subsurface sediment mobilization and mud volcanism in Candor and Coprates Chasmata, Valles Marineris, Mars

    NASA Astrophysics Data System (ADS)

    Okubo, Chris H.

    2016-05-01

    Populations of distinctive knobs, rings and lobate structures are observed in the Candor and Coprates Chasmata regions of Mars. To interpret the formation mechanisms of these landforms, I investigate their morphologies, facies, superposition and crosscutting relationships using data from the High Resolution Imaging Science Experiment (HiRISE) and the High Resolution Stereo Camera (HRSC). The knobs and rings have quasi-circular to elliptical shapes in map view, with basal diameters between several hundred meters and three kilometers. The knobs rise ∼10 to 350 m above the surrounding terrain, while the rings are ∼10 to 70 m tall. In three dimensions the knobs have a rounded cone shape, and some knobs exhibit a summit depression, which in some examples contains a subordinate mound. The rings have rounded to sharp crests and in some instances contain subordinate rings and mounds. The lobate structures are commonly ∼1 to 2 km wide, ∼3 to 5 km long and rise up to 50 m above the surrounding terrain. The lobate structures partially or completely encircle some knobs, rings and irregularly shaped rock masses. The knobs, rings and lobate structures exhibit massive and stratified facies, with some structures exhibiting both, such as a massive central rock mass surrounded by outwardly dipping layers. I interpret these landforms as mud volcanoes, injectites and mud flows based on superposition and cross-cutting relationships as well as similarities between the morphologies and facies of these landforms with terrestrial products of mud volcanism. I infer the source of sediment for this mud volcanism to be the Hesperian eolian deposits that occur within these chasmata. Further, I suggest that groundwater upwelling during the Hesperian to possibly the Early Amazonian facilitated the mobilization of these sediments within the subsurface and thereby contributed to the ensuing mud volcanism. Based on these results, I propose that the Candor Chaos formed through subsurface

  4. The role of condensed carbonaceous materials on the sorption of hydrophobic organic contaminants in subsurface sediments.

    PubMed

    Jeong, Sangjo; Wander, Michelle M; Kleineidam, Sybille; Grathwohl, Peter; Ligouis, Bertrand S; Werth, Charles J

    2008-03-01

    The identification and characterization of carbonaceous materials (CMs) that control hydrophobic organic chemical (HOC) sorption is essential to predict the fate and transport of HOCs in soils and sediments. The objectives of this paper are to determine the types of CMs that control HOC sorption in the oxidized and reduced zones of a glacially deposited groundwater sediment in central Illinois, with a special emphasis on the roles of kerogen and black carbon. After collection, the sediments were treated to obtain fractions of the sediment samples enriched in different types of CMs (e.g., humic acid, kerogen, black carbon), and selected fractions were subject to quantitative petrographic analysis. The original sediments and their enrichment fractions were evaluated for their ability to sorb trichloroethene (TCE), a common groundwater pollutant. Isotherm results and mass fractions of CM enrichments were used to calculate sorption contributions of different CMs. The results indicate that CMs in the heavy fractions dominate sorption because of their greater mass. Black carbon mass fractions of total CMs in the reduced sediments were calculated and used to estimate the sorption contribution of these materials. Results indicate that in the reduced sediments, black carbon may sequester as much as 32% of the sorbed TCE mass, butthat kerogen and humin are the dominant sorption environments. Organic carbon normalized sorption coefficients (K(oc)) were compared to literature values. Values for the central Illinois sediments are relatively large and in the range of values determined for materials high in kerogen and humin. This work demonstrates the advantage of using both sequential chemical treatment and petrographic analysis to analyze the sorption contributions of different CMs in natural soils and sediments, and the importance of sorption to natural geopolymers in groundwater sediments not impacted by anthropogenic sources of black carbon.

  5. In-Situ Ultrasonic Characterization of Patterns of Sediment Surface Roughness and Subsurface Volume Inhomogeneities

    DTIC Science & Technology

    2016-06-07

    was successfully converted to ocean-going use . An aluminum pressure housing (sled-type) was created containing the ultrasound machine, VCR, battery ...successfully images surface and sub-surface biogenic structure non-invasively in the laboratory (ultrasound) and convert the technology for use in...pressure housing for it waterproof to 50 m water depth. We will deploy the unit in the field with the use of divers during the summer in the

  6. Interactions Between Fe(III)-oxides and Fe(III)-phyllosilicates During Microbial Reduction 2: Natural Subsurface Sediments

    SciTech Connect

    Wu, T.; Griffin, A. M.; Gorski, C. A.; Shelobolina, E. S.; Xu, H.; Kukkadapu, R. K.; Roden, E. E.

    2016-04-19

    Dissimilatory microbial reduction of solid-phase Fe(III)-oxides and Fe(III)-bearing phyllosilicates (Fe(III)-phyllosilicates) is an important process in anoxic soils, sediments, and subsurface materials. Although various studies have documented the relative extent of microbial reduction of single-phase Fe(III)-oxides and Fe(III)-phyllosilicates, detailed information is not available on interaction between these two processes in situations where both phases are available for microbial reduction. The goal of this research was to use the model dissimilatory iron-reducing bacterium (DIRB) Geobacter sulfurreducens to study Fe(III)-oxide vs. Fe(III)-phyllosilicate reduction in a range of subsurface materials and Fe(III)-oxide stripped versions of the materials. Low temperature (12K) Mossbauer spectroscopy was used to infer changes in the relative abundances of Fe(III)-oxide, Fe(III)-phyllosilicate, and phyllosilicate-associated Fe(II) (Fe(II)-phyllosilicate). A Fe partitioning model was employed to analyze the fate of Fe(II) and assess the potential for abiotic Fe(II)-catalyzed reduction of Fe(III)-phyllosilicates. The results showed that in most cases Fe(III)- oxide utilization dominated (70-100 %) bulk Fe(III) reduction activity, and that electron transfer from oxide-derived Fe(II) played only a minor role (ca. 10-20 %) in Fe partitioning. In addition, the extent of Fe(III)-oxide reduction was positively correlated to surface area-normalized cation exchange capacity and the phyllosilicate-Fe(III)/total Fe(III) ratio, which suggests that the phyllosilicates in the natural sediments promoted Fe(III)-oxide reduction by binding of oxide-derived Fe(II), thereby enhancing Fe(III)-oxide reduction by reducing or delaying the inhibitory effect that Fe(II) accumulation on oxide and DIRB cell surfaces has on Fe(III)-oxide reduction. In general our results suggest that although Fe(III)-oxide reduction is likely to dominate bulk Fe(III) reduction in most subsurface sediments, Fe

  7. Isolation and microbial reduction of Fe(III) phyllosilicates from subsurface sediments

    SciTech Connect

    Wu, Tao; Shelobolina, Evgenya S.; Xu, Huifang; Konishi, Hiromi; Kukkadapu, Ravi K.; Roden, Eric E.

    2012-10-12

    Fe(III)-bearing phyllosilicates can be important sources of Fe(III) for dissimilatory microbial iron reduction in clay-rich anoxic soils and sediments. The goal of this research was to isolate Fe(III) phyllosilicate phases, and if possible, Fe(III) oxide phases, from a weathered shale saprolite sediment in order to permit experimentation with each phase in isolation. Physical partitioning by density gradient centrifugation did not adequately separate phyllosilicate and Fe(III) oxide phases (primarily nanoparticulate goethite). Hence we examined the ability of chemical extraction methods to remove Fe(III) oxides without significantly altering the properties of the phyllosilicates. XRD analysis showed that extraction with oxalate alone or oxalate in the presence of added Fe(II) altered the structure of Fe-bearing phyllosilicates in the saprolite. In contrast, citrate-bicarbonate-dithionite (CBD) extraction at room temperature and 80C led to minimal alteration of phyllosilicate structures. Reoxidation of CDB-extracted sediment with H2O2 restored phyllosilicate structure (i.e. d-spacing) and redox speciation to conditions similar to that in the pristine sediment. The extent of microbial (Geobacter sulfurreducens) reduction of Fe(III) phyllosilicates isolated by CDB extraction (ca. 16 %) was comparable to what took place in pristine sediments as determined by Mossbauer spectroscopy (ca. 18 % reduction). These results suggest that materials isolated by CDB extraction and H2O2 reoxidation are appropriate targets for detailed studies of natural soil/sediment Fe(III) phyllosilicate reduction.

  8. A simulation study of infiltration into surficial sediments at the Subsurface Disposal Area, Idaho National Engineering Laboratory

    SciTech Connect

    Martian, P.; Magnuson, S.O.

    1994-04-01

    Soil moisture monitoring data in the surficial sediments at the Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory were used to calibrate two numerical infiltration models. The calibration was performed with the ultimate goal of providing a reliable estimate of hydraulic properties and infiltration amounts to be used in other modeling efforts. Two neutron probe access tubes and a tensiometer nest were monitored from 1986 to 1990 and again during 1993. The field measurements of moisture content and matrix potential inside the SDA were used as calibration data for the two locations. The two locations showed vastly different behavior, which was well captured in the models. The average root mean square error between simulated and measured moisture contents over the simulation period was 0.03 and 0.06 for the two locations. The hydraulic parameters resulting from the calibration compared favorably with laboratory and field scale estimates. The simulation results also provided the opportunity to partially explain infiltration and redistribution processes occurring at the SDA. The underlying fractured basalt appears to behave similar to a capillary barrier. This behavior inhibits moisture movement into the underlying basalts until moisture contents in the overlying silts approach saturation. As a result, a large proportion of recharge occurring at the SDA may be due to spring snowmelt, when the surficial sediments become nearly saturated. The results also indicated that a unit gradient boundary condition (free drainage due to gravity) at the bottom of the silts is not appropriate because of the very low relative hydraulic conductivity of the basalts. Finally, the amount of water moving into the SDA subsurface from spring snowmelt appears larger than cumulative snowfall, indicating that snow drifting due to local topography as well as current snow management practices may have a substantial influence on local infiltration.

  9. Aminostratigraphy of surface and subsurface Quaternary sediments, North Carolina coastal plain, USA

    USGS Publications Warehouse

    Wehmiller, J. F.; Thieler, E.R.; Miller, D.; Pellerito, V.; Bakeman, Keeney V.; Riggs, S.R.; Culver, S.; Mallinson, D.; Farrell, K.M.; York, L.L.; Pierson, J.; Parham, P.R.

    2010-01-01

    The Quaternary stratigraphy and geochronology of the Albemarle Embayment of the North Carolina (NC) Coastal Plain is examined using amino acid racemization (AAR) in marine mollusks, in combination with geophysical, lithologic, and biostratigraphic analysis of 28 rotasonic cores drilled between 2002 and 2006. The Albemarle Embayment is bounded by structural highs to the north and south, and Quaternary strata thin westward toward the Suffolk paleoshoreline, frequently referred to as the Suffolk Scarp. The Quaternary section is up to ???90. m thick, consists of a variety of estuarine, shelf, back-barrier, and lagoonal deposits, and has been influenced by multiple sea-level cycles. The temporal resolution of the amino acid racemization method is tested statistically and with the stratigraphic control provided by this geologic framework, and it is then applied to the correlation and age estimation of subsurface units throughout the region. Over 500 specimens (primarily Mercenaria and Mulinia) from the subsurface section have been analyzed using either gas chromatographic (GC) or reverse-phase liquid chromatographic (RPLC) techniques. The subsurface stratigraphic data are compared with AAR results from numerous natural or excavated exposures from the surrounding region, as well as results from NC beach collections, to develop a comprehensive aminostratigraphic database for the entire Quaternary record within the NC coastal system. Age mixing, recognized in the beach collections, is also seen in subsurface sections, usually where major seismic reflections or core lithology indicate the presence of stratigraphic discontinuities. Kinetic models for racemization are tested within the regional stratigraphic framework, using either radiocarbon or U-series calibrations or comparison with regional biostratigraphy. Three major Pleistocene aminozones [AZ2, AZ3, and AZ4] are found throughout the region, all being found in superposition in several cores. Each can be subdivided

  10. Aminostratigraphy of surface and subsurface Quaternary sediments, North Carolina coastal plain, USA

    USGS Publications Warehouse

    Wehmiller, John F.; Thieler, E. Robert; Miller, D.; Pellerito, V.; Bakeman, Keeney V.; Riggs, S.R.; Culver, S.; Mallinson, D.; Farrell, K.M.; York, L.L.; Pierson, J.; Parham, P.R.

    2010-01-01

    The Quaternary stratigraphy and geochronology of the Albemarle Embayment of the North Carolina (NC) Coastal Plain is examined using amino acid racemization (AAR) in marine mollusks, in combination with geophysical, lithologic, and biostratigraphic analysis of 28 rotasonic cores drilled between 2002 and 2006. The Albemarle Embayment is bounded by structural highs to the north and south, and Quaternary strata thin westward toward the Suffolk paleoshoreline, frequently referred to as the Suffolk Scarp. The Quaternary section is up to ∼90 m thick, consists of a variety of estuarine, shelf, back-barrier, and lagoonal deposits, and has been influenced by multiple sea-level cycles. The temporal resolution of the amino acid racemization method is tested statistically and with the stratigraphic control provided by this geologic framework, and it is then applied to the correlation and age estimation of subsurface units throughout the region. Over 500 specimens (primarily Mercenaria and Mulinia) from the subsurface section have been analyzed using either gas chromatographic (GC) or reverse-phase liquid chromatographic (RPLC) techniques. The subsurface stratigraphic data are compared with AAR results from numerous natural or excavated exposures from the surrounding region, as well as results from NC beach collections, to develop a comprehensive aminostratigraphic database for the entire Quaternary record within the NC coastal system. Age mixing, recognized in the beach collections, is also seen in subsurface sections, usually where major seismic reflections or core lithology indicate the presence of stratigraphic discontinuities. Kinetic models for racemization are tested within the regional stratigraphic framework, using either radiocarbon or U-series calibrations or comparison with regional biostratigraphy. Three major Pleistocene aminozones [AZ2, AZ3, and AZ4] are found throughout the region, all being found in superposition in several cores. Each can be subdivided

  11. Spatial and temporal variations of microbial properties at different scales in shallow subsurface sediments

    SciTech Connect

    Zhang, Chuanlun; Pfiffner, S.M.; Phelps, T.J.

    1997-12-31

    Microbial abundance, activity, and community-level physiological profiles (CLPP) were examined at centimeter and meter scales in the subsurface environment at a site near Oyster, VA. At the centimeter scale, variations in aerobic culturable heterotrophs (ACH) and glucose mineralization rates (GMR) were highest in the water table zone, indicating that water availability has a major effect on variations in microbial abundance and activity. At the meter scale, ACH and microaerophiles decreased significantly with depth, whereas anaerobic GMR often increased with depth; this may indicate low redox potentials at depth caused by microbial consumption of oxygen. Data of CUP indicated that the microbial community (MC) in the soybean field exhibited greater capability to utilize multiple carbon sources than MC in the corn field. This difference may reflect nutrient availability associated with different crops (soybean vs corn). By using a regression model, significant spatial and temporal variations were observed for ACH, microaerophiles, anaerobic GMR, and CLPP. Results of this study indicated that water and nutrient availability as well as land use could have a dominant effect on spatial and temporal variations in microbial properties in shallow subsurface environments. 32 refs., 3 figs., 3 tabs.

  12. Controls on subsurface methane fluxes and shallow gas formation in Baltic Sea sediment (Aarhus Bay, Denmark)

    NASA Astrophysics Data System (ADS)

    Flury, Sabine; Røy, Hans; Dale, Andrew W.; Fossing, Henrik; Tóth, Zsuzsanna; Spiess, Volkhard; Jensen, Jørn Bo; Jørgensen, Bo Barker

    2016-09-01

    Shallow gas accumulates in coastal marine sediments when the burial rate of reactive organic matter beneath the sulfate zone is sufficiently high and the methanogenic zone is sufficiently deep. We investigated the controls on methane production and free methane gas accumulation along a 400 m seismo-acoustic transect across a sharp transition from gas-free into gas-bearing sediment in Aarhus Bay (Denmark). Twelve gravity cores were taken, in which the pore water was analyzed for inorganic solutes while rates of organic carbon mineralization were measured experimentally by 35SO42- radiotracer method. The thickness of organic-rich Holocene mud increased from 5 to 10 m along the transect concomitant with a shallowing of the depth of the sulfate-methane transition from >4 m to 2.5 m. In spite of drastic differences in the distribution of methane and sulfate in the sediment along the transect, there were only small differences in total mineralization, and methanogenesis was only equivalent to about 1% of sulfate reduction. Shallow gas appeared where the mud thickness exceeded 8-9 m. Rates of methanogenesis increased along the transect as did the upward diffusive flux of methane. Interestingly, the increase in the sedimentation rate and Holocene mud thickness had only a modest direct effect on methanogenesis rates in deep sediments. This increase in methane flux, however, triggered a shallowing of the sulfate-methane transition which resulted in a large increase in methanogenesis at the top of the methanogenic zone. Thus, our results demonstrate a positive feedback mechanism that causes a strong enhancement of methanogenesis and explains the apparently abrupt appearance of gas when a threshold thickness of organic-rich mud is exceeded.

  13. Potential for microbial H2 and metal transformations associated with novel bacteria and archaea in deep terrestrial subsurface sediments.

    PubMed

    Hernsdorf, Alex W; Amano, Yuki; Miyakawa, Kazuya; Ise, Kotaro; Suzuki, Yohey; Anantharaman, Karthik; Probst, Alexander; Burstein, David; Thomas, Brian C; Banfield, Jillian F

    2017-03-28

    Geological sequestration in deep underground repositories is the prevailing proposed route for radioactive waste disposal. After the disposal of radioactive waste in the subsurface, H2 may be produced by corrosion of steel and, ultimately, radionuclides will be exposed to the surrounding environment. To evaluate the potential for microbial activities to impact disposal systems, we explored the microbial community structure and metabolic functions of a sediment-hosted ecosystem at the Horonobe Underground Research Laboratory, Hokkaido, Japan. Overall, we found that the ecosystem hosted organisms from diverse lineages, including many from the phyla that lack isolated representatives. The majority of organisms can metabolize H2, often via oxidative [NiFe] hydrogenases or electron-bifurcating [FeFe] hydrogenases that enable ferredoxin-based pathways, including the ion motive Rnf complex. Many organisms implicated in H2 metabolism are also predicted to catalyze carbon, nitrogen, iron and sulfur transformations. Notably, iron-based metabolism is predicted in a novel lineage of Actinobacteria and in a putative methane-oxidizing ANME-2d archaeon. We infer an ecological model that links microorganisms to sediment-derived resources and predict potential impacts of microbial activity on H2 consumption and retardation of radionuclide migration.The ISME Journal advance online publication, 28 March 2017; doi:10.1038/ismej.2017.39.

  14. Origin and Migration of Methane in Gas Hydrate-bearing Sediments Relevant to Their Subsurface Occurrences in The Nankai Trough

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Waseda, A.

    2003-04-01

    Although gas hydrates are known to occur in the Arctic in association with permafrost regimes and in the deep offshore at the continental margins, the geologic and geophysical issues controlling their occurrences and distributions are still remained. The Nankai Trough runs along the Japanese Island, where forearc basins and accretionary prisms developed extensively and BSRs (bottom simulating reflector) have been recognized widely. High resolution seismic surveys in 1997, 2001 and 2002 and drilling the Nankai Trough wells conducted by the METI (Ministry of Economy, Trade and Industry) have revealed the subsurface gas hydrate widely distributed at the depth interval from 200 to 270 mbsf. All the core samples containing gas hydrates were subjected to X-ray CT imagery so as to observe sedimentary textures and occurrences inside of cores without disturbances before provided to various analyses. Subsurface occurrences of natural gas hydrate can be classified into six types; 1) pore-space hydrate, 2) platy hydrate, 3) layered/massive hydrate, 4) disseminated hydrate, 5) nodule hydrate and 6) vein/dyke hydrate. The anomalies of chloride contents in pore water, core temperature depression, core observation as well as visible gas hydrates confirmed well-interconnected and highly saturated pore-space hydrates as intergranular pore filling within sand layers within the methane hydrate stability zone. Hydrate saturations are higher than 60 % throughout most hydrate-dominant sand layers and in some parts close to 100% pore saturation. Muddy sediments such as silts and clays were free of hydrate or contained low concentrations. Carbon and hydrogen isotope compositions of CH4 and hydrocarbon compositions contained in gas hydrate indicate that methane is generated by microbial reduction of CO2. Both carbon isotope compositions of CH4 and CO2 in the sediments become heavier gradually with depths shallower than 100 mbsf. In deeper depths, the origins of hydrocarbon change from

  15. Oxidative dissolution potential of biogenic and abiogenic TcO 2 in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Fredrickson, James K.; Zachara, John M.; Plymale, Andrew E.; Heald, Steve M.; McKinley, James P.; Kennedy, David W.; Liu, Chongxuan; Nachimuthu, Ponnusamy

    2009-04-01

    Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O4-] and less mobile in the reduced form [Tc(IV)O 2· nH 2O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site on the Oak Ridge Site. Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Shewanella putrefaciens CN32 reduced Mn(III/IV) oxides and generated Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. After bioreduction and heat-killing, biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO 2-like phase in both sediments. The biogenic redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular scale speciation of Tc compared to RG. X-ray microprobe, electron microprobe, X-ray absorption spectroscopy, and micro X-ray diffraction were applied to the whole sediment and isolated Tc-containing particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 μm-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass

  16. Residence of habitat-specific anammox bacteria in the deep-sea subsurface sediments of the South China Sea: analyses of marker gene abundance with physical chemical parameters.

    PubMed

    Hong, Yi-Guo; Li, Meng; Cao, Huiluo; Gu, Ji-Dong

    2011-07-01

    Anaerobic ammonium oxidation (anammox) has been recognized as an important process for the global nitrogen cycle. In this study, the occurrence and diversity of anammox bacteria in the deep-sea subsurface sediments of the South China Sea (SCS) were investigated. Results indicated that the anammox bacterial sequences recovered from this habitat by amplifying both 16S rRNA gene and hydrazine oxidoreductase encoding hzo gene were all closely related to the Candidatus Scalindua genus. A total of 96 16S rRNA gene sequences from 346 clones were grouped into five subclusters: two subclusters affiliated with the brodae and arabica species, while three new subclusters named zhenghei-I, -II, and -III showed ≤ 97.4% nucleic acid sequence identity with other known Candidatus Scalindua species. Meanwhile, 88 hzo gene sequences from the sediments also formed five distant subclusters within hzo cluster 1c. Through fluorescent real-time PCR analysis, the abundance of anammox bacteria in deep-sea subsurface sediment was quantified by hzo genes, which ranged from 1.19 × 10(4) to 7.17 × 10(4) copies per gram of dry sediments. Combining all the information from this study, diverse Candidatus Scalindua anammox bacteria were found in the deep-sea subsurface sediments of the SCS, and they could be involved in the nitrogen loss from the fixed inventory in the habitat.

  17. Bacterial distribution and metabolic activity in subsurface sediments from a gasoline spill

    SciTech Connect

    Krauter, P.W.; Hanna, M.L.; Taylor, R.T.; Rice, D.W. Jr.

    1992-05-01

    At the Lawrence Livermore National Laboratory (LLNL) in California, a records inspection in 1979 indicated an inventory of about 17,500 gal was missing from underground fuel tanks. A leak or leaks in the southernmost tank and/or pipe lines were suspected to be the source of the loss. All four tanks were taken out of service and filled with sand in 1980. The gasoline spill cleanup effort affords an opportunity to study the collective effect of fuel hydrocarbons (HCs) on the indigenous microbial population within the heterogeneous alluvial subsurface environment. This paper presents the early results of an ongoing study to (1) characterize naturally acclimated microbial populations capable of transforming HCs and (2) understand the effects of environmental factors on these biotransformations.

  18. Discriminative detection and enumeration of microbial life in marine subsurface sediments.

    PubMed

    Morono, Yuki; Terada, Takeshi; Masui, Noriaki; Inagaki, Fumio

    2009-05-01

    Detection and enumeration of microbial life in natural environments provide fundamental information about the extent of the biosphere on Earth. However, it has long been difficult to evaluate the abundance of microbial cells in sedimentary habitats because non-specific binding of fluorescent dye and/or auto-fluorescence from sediment particles strongly hampers the recognition of cell-derived signals. Here, we show a highly efficient and discriminative detection and enumeration technique for microbial cells in sediments using hydrofluoric acid (HF) treatment and automated fluorescent image analysis. Washing of sediment slurries with HF significantly reduced non-biological fluorescent signals such as amorphous silica and enhanced the efficiency of cell detachment from the particles. We found that cell-derived SYBR Green I signals can be distinguished from non-biological backgrounds by dividing green fluorescence (band-pass filter: 528/38 nm (center-wavelength/bandwidth)) by red (617/73 nm) per image. A newly developed automated microscope system could take a wide range of high-resolution image in a short time, and subsequently enumerate the accurate number of cell-derived signals by the calculation of green to red fluorescence signals per image. Using our technique, we evaluated the microbial population in deep marine sediments offshore Peru and Japan down to 365 m below the seafloor, which provided objective digital images as evidence for the quantification of the prevailing microbial life. Our method is hence useful to explore the extent of sub-seafloor life in the future scientific drilling, and moreover widely applicable in the study of microbial ecology.

  19. Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses.

    PubMed

    Feyereisen, Gary W; Francesconi, Wendy; Smith, Douglas R; Papiernik, Sharon K; Krueger, Erik S; Wente, Christopher D

    2015-03-01

    Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for movement of sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine the reduction in drainage effluent total suspended sediment (TSS) and phosphorus (P) concentrations and loads when open surface inlets were replaced with blind (in gravel capped with 30 cm of soil) or gravel (in very coarse sand/fine gravel) inlets. In Indiana, a pair of closed depressions in adjacent fields was fitted with open inlet tile risers and blind inlets in 2005 and monitored for flow and water chemistry. Paired comparisons on a storm event basis during the growing season for years 2006 to 2013 showed that TSS loads were 40.4 and 14.4 kg ha event for tile risers and blind inlets, respectively. Total P (TP) and soluble reactive P (SRP) loads were 66 and 50% less for the blind inlets, respectively. In Minnesota, TSS and SRP concentrations were monitored for 3 yr before and after modification of 24 open inlets to gravel inlets in an unreplicated large-field on-farm study. Median TSS concentrations were 97 and 8.3 mg L and median SRP concentrations were 0.099 and 0.064 mg L for the open inlet and gravel inlet periods, respectively. Median TSS and SRP concentrations were elevated for snowmelt vs. non-snowmelt seasons for open and gravel inlets. Both replacement designs reduced suspended sediment and P concentrations and loads. The Indiana study suggests blind inlets will be effective beyond a 10-yr service life.

  20. Mineral-Association and Activity of Bacteria and Archaea in the Deep Subsurface South Pacific Gyre Sediment

    NASA Astrophysics Data System (ADS)

    Steele, J. A.; Dekas, A. E.; Harrison, B. K.; Morono, Y.; Inagaki, F.; Ziebis, W.; Orphan, V. J.

    2012-12-01

    Although the subsurface biosphere is now recognized as an important reservoir of life on our planet, until recently the microbial community beneath open-ocean oligotrophic gyres (making up the majority of the seafloor) has just begun to be studied in detail. IODP Expedition 329 and the KNOX-022RR site survey cruise have taken some of the first steps at characterizing the microbial community beneath the South Pacific Gyre, a region with low organic carbon burial rates (10-8 and 10-10 moles C cm-1 yr-1), deep oxygen penetration (sediments are oxidized to the basement), and low prokaryotic cell counts (106 cells cm-3 to <103 cells cm-3). In these sediments, the dominant fraction of organic carbon may be aggregated or adsorbed to minerals, suggesting that microbes that are able to grow on the minerals may create potential "hotspots" of activity. In this study, we performed magnetic separation on oligotrophic sediment samples and examined the bacterial and archaeal communities using 16S rRNA tag sequencing. To determine if the mineral-associated cells were autotrophic and/or utilizing nitrate, we performed long-term (20 month) incubations with 13CO2 and 15NO3- from sediment taken at depths ~2-70 mbsf beneath the oligotrophic gyre and outside of the oligotrophic gyre (IODP Exp. 329 stations U1368-U1371). Subsequently we used the DNA stain SYBR Green I, and CARD-FISH-NanoSIMS to identify cells which were actively taking up the isotopic label. We then used SEM-EDS to identify the mineral particle composition. Preliminary results found the magnetic fraction in oligotrophic sediment (KNOX-022RR station SPG-5) from 1.2-2.6 mbsf showed a greater diversity of both bacteria and archaea. OTUs from Chloroflexi groups SO85 and SAR202 were dominant in the magnetic fraction. Firmicutes, Bacteroidetes, δ-Proteobacteria, Verrucomicrobia, Deferribacteres, WS3, OP10, and OP1 OTUs were found only in the magnetic fraction. Crenarchaeal OTUs from Marine Benthic Group B and Marine Group I

  1. MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

    SciTech Connect

    Beyenal, Haluk; McLEan, Jeff; Majors, Paul; Fredrickson, Jim

    2013-11-14

    The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

  2. An Integrated Assessment of Geochemical and Community Structure Determinants of Metal Reduction Rates in Subsurface Sediments

    SciTech Connect

    Joel E. Kostka

    2008-03-24

    This project represented a joint effort between Oak Ridge National Laboratory (ORNL), the University of Tennessee (UT), and Florida State University (FSU). ORNL served as the lead in-stitution with Dr. A.V. Palumbo responsible for project coordination, integration, and deliver-ables. In situ uranium bioremediation is focused on biostimulating indigenous microorganisms through a combination of pH neutralization and the addition of large amounts of electron donor. Successful biostimulation of U(VI) reduction has been demonstrated in the field and in the laboratory. However, little data is available on the dynamics of microbial populations capable of U(VI) reduction, and the differences in the microbial community dynamics between proposed electron donors have not been explored. In order to elucidate the potential mechanisms of U(VI) reduction for optimization of bioremediation strategies, structure-function relationships of microbial populations were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate from the Oak Ridge Field Research Center (ORFRC), Oak Ridge, Tennessee.

  3. A New Sensitive GC-MS-based Method for Analysis of Dipicolinic Acid and Quantifying Bacterial Endospores in Deep Marine Subsurface Sediment

    NASA Astrophysics Data System (ADS)

    Fang, J.

    2015-12-01

    Marine sediments cover more than two-thirds of the Earth's surface and represent a major part of the deep biosphere. Microbial cells and microbial activity appear to be widespread in these sediments. Recently, we reported the isolation of gram-positive anaerobic spore-forming piezophilic bacteria and detection of bacterial endospores in marine subsurface sediment from the Shimokita coalbed, Japan. However, the modern molecular microbiological methods (e.g., DNA-based microbial detection techniques) cannot detect bacterial endospore, because endospores are impermeable and are not stained by fluorescence DNA dyes or by ribosomal RNA staining techniques such as catalysed reporter deposition fluorescence in situ hybridization. Thus, the total microbial cell abundance in the deep biosphere may has been globally underestimated. This emphasizes the need for a new cultivation independent approach for the quantification of bacterial endospores in the deep subsurface. Dipicolinic acid (DPA, pyridine-2,6-dicarboxylic acid) is a universal and specific component of bacterial endospores, representing 5-15wt% of the dry spore, and therefore is a useful indicator and quantifier of bacterial endospores and permits to estimate total spore numbers in the subsurface biosphere. We developed a sensitive analytical method to quantify DPA content in environmental samples using gas chromatography-mass spectrometry. The method is sensitive and more convenient in use than other traditional methods. We applied this method to analyzing sediment samples from the South China Sea (obtained from IODP Exp. 349) to determine the abundance of spore-forming bacteria in the deep marine subsurface sediment. Our results suggest that gram-positive, endospore-forming bacteria may be the "unseen majority" in the deep biosphere.

  4. Biogeochemistry and biodiversity of methane cycling in subsurface marine sediments (Skagerrak, Denmark).

    PubMed

    Parkes, R John; Cragg, Barry A; Banning, Natasha; Brock, Fiona; Webster, Gordon; Fry, John C; Hornibrook, Ed; Pancost, Richard D; Kelly, Sam; Knab, Nina; Jørgensen, Bo B; Rinna, Joachim; Weightman, Andrew J

    2007-05-01

    This biogeochemical, molecular genetic and lipid biomarker study of sediments ( approximately 4 m cores) from the Skagerrak (Denmark) investigated methane cycling in a sediment with a clear sulfate-methane-transition zone (SMTZ) and where CH(4) supply was by diffusion, rather than by advection, as in more commonly studied seep sites. Sulfate reduction removed sulfate by 0.7 m and CH(4) accumulated below. (14)C-radiotracer measurements demonstrated active H(2)/CO(2) and acetate methanogenesis and anaerobic oxidation of CH(4) (AOM). Maximum AOM rates occurred near the SMTZ ( approximately 3 nmol cm(-3) day(-1) at 0.75 m) but also continued deeper, overall, at much lower rates. Maximum rates of H(2)/CO(2) and acetate methanogenesis occurred below the SMTZ but H(2)/CO(2) methanogenesis rates were x 10 those of acetate methanogenesis, and this was consistent with initial values of (13)C-depleted CH(4) (delta(13)C c.-80 per thousand). Areal AOM and methanogenic rates were similar ( approximately 1.7 mmol m(-2) day(-1)), hence, CH(4) flux is finely balanced. A 16S rRNA gene library from 1.39 m combined with methanogen (T-RFLP), bacterial (16S rRNA DGGE) and lipid biomarker depth profiles showed the presence of populations similar to some seep sites: ANME-2a (dominant), ANME-3, Methanomicrobiales, Methanosaeta Archaea, with abundance changes with depth corresponding to changes in activities and sulfate-reducing bacteria (SRB). Below the SMTZ to approximately 1.7 m CH(4) became progressively more (13)C depleted (delta(13)C -82 per thousand) indicating a zone of CH(4) recycling which was consistent with the presence of (13)C-depleted archaeol (delta(13)C -55 per thousand). Pore water acetate concentrations decreased in this zone (to approximately 5 microM), suggesting that H(2), not acetate, was an important CH(4) cycling intermediate. The potential biomarkers for AOM-associated SRB, non-isoprenoidal ether lipids, increased below the SMTZ but this distribution reflected 16S

  5. Distribution of microbial biomass and the potential for anaerobic respiration in Hanford Site 300 Area subsurface sediment

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Peacock, Aaron D.; McKinley, James P.; Resch, Charles T.; Fredrickson, Jim K.; Konopka, Allan

    2012-02-01

    Subsurface sediments were recovered from a 52 m deep borehole cored in the 300 Area of the Hanford Site in southeastern Washington State to assess the potential for biogeochemical transformation of radionuclide contaminants. Microbial analyses were made on 17 sediment samples traversing multiple geological units: the oxic coarse-grained Hanford formation (9-17.4 m), the oxic fine-grained upper Ringold Formation (17.7-18.1 m), and the reduced Ringold Formation (18.3-52m). Microbial biomass (measured as phospholipid) ranged from 7-974 pmols per g in discrete samples, with the highest numbers found in the Hanford formation. On average, strata below 17.4 m had 13-fold less biomass than those from shallower strata. The nosZ gene encoding nitrous oxide reductase had an abundance of 5-17% relative to total 16S rRNA genes below 18.3 m and <5% above 18.1 m. Most nosZ sequences were affiliated with Ochrobactrum anthropi (97% sequence similarity) or had a nearest neighbor of Achromobacter xylosoxidans (90% similarity). Passive multilevel sampling of groundwater geochemistry demonstrated a redox gradient in the 1.5 m region between the Hanford-Ringold formation contact and the Ringold oxic-anoxic interface. Within this zone, copies of the dsrA gene and Geobacteraceae had the highest relative abundance. The majority of dsrA genes detected near the interface were related to Desulfotomaculum sp.. These analyses indicate that the region just below the contact between the Hanford and Ringold formations is a zone of active biogeochemical redox cycling.

  6. Methanobacterium movilense sp. nov., a hydrogenotrophic, secondary-alcohol-utilizing methanogen from the anoxic sediment of a subsurface lake.

    PubMed

    Schirmack, Janosch; Mangelsdorf, Kai; Ganzert, Lars; Sand, Wolfgang; Hillebrand-Voiculescu, Alexandra; Wagner, Dirk

    2014-02-01

    A novel strain of methanogenic archaea, designated MC-20(T), was isolated from the anoxic sediment of a subsurface lake in Movile Cave, Mangalia, Romania. Cells were non-motile, Gram-stain-negative rods 3.5-4.0 µm in length and 0.6-0.7 µm in width, and occurred either singly or in short chains. Strain MC-20(T) was able to utilize H2/CO2, formate, 2-propanol and 2-butanol as substrate, but not acetate, methanol, ethanol, dimethyl sulfide, monomethylamine, dimethylamine or trimethylamine. Neither trypticase peptone nor yeast extract was required for growth. The major membrane lipids of strain MC-20(T) were archaeol phosphatidylethanolamine and diglycosyl archaeol, while archaeol phosphatidylinositol and glycosyl archaeol were present only in minor amounts. Optimal growth was observed at 33 °C, pH 7.4 and 0.08 M NaCl. Based on phylogenetic analysis of 16S rRNA gene sequences, strain MC-20(T) was closely affiliated with Methanobacterium oryzae FPi(T) (similarity 97.1%) and Methanobacterium lacus 17A1(T) (97.0%). The G+C content of the genomic DNA was 33.0 mol%. Based on phenotypic and genotypic differences, strain MC-20(T) was assigned to a novel species of the genus Methanobacterium for which the name Methanobacterium movilense sp. nov. is proposed. The type strain is MC-20(T) ( = DSM 26032(T) = JCM 18470(T)).

  7. Biodegradation of 2-methyl, 2-ethyl, and 2-hydroxypyridine by an Arthrobacter sp. isolated from subsurface sediment.

    PubMed

    O'Loughlin, E J; Sims, G K; Traina, S J

    1999-04-01

    A bacterium capable of degrading 2-methylpyridine was isolated by enrichment techniques from subsurface sediments collected from an aquifer located at an industrial site that had been contaminated with pyridine and pyridine derivatives. The isolate, identified as an Arthrobacter sp., was capable of utilizing 2-methylpyridine, 2-ethylpyridine, and 2-hydroxypyridine as primary C, N, and energy sources. The isolate was also able to utilize 2-, 3-, and 4-hydroxybenzoate, gentisic acid, protocatechuic acid and catechol, suggesting that it possesses a number of enzymatic pathways for the degradation of aromatic compounds. Degradation of 2-methylpyridine, 2-ethylpyridine, and 2-hydroxypyridine was accompanied by growth of the isolate and release of ammonium into the medium. Degradation of 2-methylpyridine was accompanied by overproduction of riboflavin. A soluble blue pigment was produced by the isolate during the degradation of 2-hydroxypyridine, and may be related to the diazadiphenoquinones reportedly produced by other Arthrobacter spp. when grown on 2-hydroxypyridine. When provided with 2-methylpyridine, 2-ethylpyridine, and 2-hydroxypyridine simultaneously, 2-hydroxypyridine was rapidly and preferentially degraded; however there was no apparent biodegradation of either 2-methylpyridine or 2-ethylpyridine until after a seven day lag. The data suggest that there are differences between the pathway for 2-hydroxypyridine degradation and the pathways(s) for 2-methylpyridine and 2-ethylpyridine.

  8. Dissimilatory Bacterial Reduction of Al-Substituted Goethite in Subsurface Sediments

    SciTech Connect

    Kukkadapu, Ravi K.; Zachara, John M.; Smith, Steven C.; Fredrickson, Jim K.; Liu, Chongxuan

    2001-09-13

    Microbiologic reduction of the 0.2-2.0 mm size fraction of an Atlantic coastal plain sediment (Eatontown) was investigated using a dissimilatory Fe(III)-reducing bacterium (Shewanella putrefaciens, strain CN32) to evaluate mineralogic controls on the rate and extent of Fe(III) reduction and resulting distribution of biogenic Fe(II). Mössbauer spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) was used to show that the sedimentary Fe(III) oxide was Al-substituted goethite (11-17% Al) that existed as 1-5 mm aggregates of indistinct morphology. Bioreduction experiments were performed in two buffers [HCO3-, 1,4-piperazinediethansulfonic acid (PIPES)] both without and with 2,6-anthraquinone disulfonate (AQDS), an electron shuttle. The production of biogenic Fe(II) and the distribution of Al (aqueous and sorbed) were followed over time, as was formation of Fe(II) biominerals and physical/chemical changes to the goethite.

  9. The effects of temperature and motility on the advective transport of a deep subsurface bacteria through saturated sediment

    SciTech Connect

    McCaulou, Douglas Ray

    1993-01-01

    Replicate column experiments were done to quantify the effects of temperature and bacterial motility on advective transport through repacked, but otherwise unaltered, natural aquifer sediment. The bacteria used in this study, A0500, was a flagellated, spore-forming rod isolated from the deep subsurface at DOE`s Savannah River Laboratory. Motility was controlled by turning on flagellar metabolism at 18°C but off at 40°α), estimated using a steady-state filtration model. The observed greater microsphere removal at the higher temperature agreed with the physical-chemical model, but bacteria removal at 18{degrees}C was only half that at 4°C. The sticking efficiency for non-motile A0500 (4°C) was over three times that of the motile A0500 (18°C), 0.073 versus 0.022 respectively. Analysis of complete breakthrough curves using a non-steady, kinetically limited, transport model to estimate the time scales of attachment and detachment suggested that motile A 0500 bacteria traveled twice as far as non-motile A 0500 bacteria before becoming attached. Once attached, non-motile colloids detached on the time scale of 9 to 17 days. The time scale for detachment of motile A0500 bacteria was shorter, 4 to 5 days. Results indicate that bacterial attachment was reversible and detachment was enhanced by bacterial motifity. The kinetic energy of bacterial motility changed the attachment-detachment kinetics in favor of the detached state. The chemical factors responsible for the enhanced transport are not known. However, motility may have caused weakly held bacteria to detach from the secondary minimum, and possibly from the primary minimum, as described by DLVO theory.

  10. Immobilization of U(VI) from oxic groundwater by Hanford 300 Area sediments and effects of Columbia River water.

    PubMed

    Ahmed, Bulbul; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I; Kemner, Kenneth M; Fredrickson, Jim K; Beyenal, Haluk

    2012-09-01

    Regions within the U.S. Department of Energy Hanford 300 Area (300 A) site experience periodic hydrologic influences from the nearby Columbia River as a result of changing river stage, which causes changes in groundwater elevation, flow direction and water chemistry. An important question is the extent to which the mixing of Columbia River water and groundwater impacts the speciation and mobility of uranium (U). In this study, we designed experiments to mimic interactions among U, oxic groundwater or Columbia River water, and 300 A sediments in the subsurface environment of Hanford 300 A. The goals were to investigate mechanisms of: 1) U immobilization in 300 A sediments under bulk oxic conditions and 2) U remobilization from U-immobilized 300 A sediments exposed to oxic Columbia River water. Initially, 300 A sediments in column reactors were fed with U(VI)-containing oxic 1) synthetic groundwater (SGW), 2) organic-amended SGW (OA-SGW), and 3) de-ionized (DI) water to investigate U immobilization processes. After that, the sediments were exposed to oxic Columbia River water for U remobilization studies. The results reveal that U was immobilized by 300 A sediments predominantly through reduction (80-85%) when the column reactor was fed with oxic OA-SGW. However, U was immobilized by 300 A sediments through adsorption (100%) when the column reactors were fed with oxic SGW or DI water. The reduced U in the 300 A sediments fed with OA-SGW was relatively resistant to remobilization by oxic Columbia River water. Oxic Columbia River water resulted in U remobilization (∼7%) through desorption, and most of the U that remained in the 300 A sediments fed with OA-SGW (∼93%) was in the form of uraninite nanoparticles. These results reveal that: 1) the reductive immobilization of U through OA-SGW stimulation of indigenous 300 A sediment microorganisms may be viable in the relatively oxic Hanford 300 A subsurface environments and 2) with the intrusion of Columbia River water

  11. Immobilization of U(VI) from Oxic Groundwater by Hanford 300 Area Sediments and Effects of Columbia River Water

    SciTech Connect

    Ahmed, B.; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I.; Kemner, Kenneth M.; Fredrickson, Jim K.; Beyenal, Haluk

    2012-09-23

    Regions within the U.S. Department of Energy Hanford 300 Area (300 A) site experience periodic hydrologic influences from the nearby Columbia River as a result of changing river stage, which causes changes in groundwater elevation, flow direction and water chemistry. An important question is the extent to which the mixing of Columbia River water and groundwater impacts the speciation and mobility of uranium (U). In this study, we designed experiments to mimic interactions among U, oxic groundwater or Columbia River water, and 300 A sediments in the subsurface environment of Hanford 300 A. The goals were to investigate mechanisms of: 1) U immobilization in 300 A sediments under bulk oxic conditions and 2) U remobilization from U-immobilized 300 A sediments exposed to oxic Columbia River water. Initially, 300 A sediments in column reactors were fed with U(VI)-containing oxic 1) synthetic groundwater (SGW), 2) organic-amended SGW (OA-SGW), and 3) de-ionized (DI) water to investigate U immobilization processes. After that, the sediments were exposed to oxic Columbia River water for U remobilization studies. The results reveal that U was immobilized by 300 A sediments predominantly through reduction (80-85%) when the column reactor was fed with oxic OA-SGW. However, U was immobilized by 300 A sediments through adsorption (100%) when the column reactors were fed with oxic SGW or DI water. The reduced U in the 300 A sediments fed with OA-SGW was relatively resistant to remobilization by oxic Columbia River water. Oxic Columbia River water resulted in U remobilization (~7%) through desorption, and most of the U that remained in the 300 A sediments fed with OA-SGW (~93%) was in the form of uraninite nanoparticles. These results reveal that: 1) the reductive immobilization of U through OA-SGW stimulation of indigenous 300 A sediment microorganisms may be viable in the relatively oxic Hanford 300 A subsurface environments and 2) with the intrusion of Columbia River water

  12. The Use of a Geomorphometric Classification to Estimate Subsurface Heterogeneity in the Unconsolidated Sediments of Mountain Watersheds

    NASA Astrophysics Data System (ADS)

    Cairns, D.; Byrne, J. M.; Jiskoot, H.; McKenzie, J. M.; Johnson, D. L.

    2013-12-01

    Groundwater controls many aspects of water quantity and quality in mountain watersheds. Groundwater recharge and flow originating in mountain watersheds are often difficult to quantify due to challenges in the characterization of the local geology, as subsurface data are sparse and difficult to collect. Remote sensing data are more readily available and are beneficial for the characterization of watershed hydrodynamics. We present an automated geomorphometric model to identify the approximate spatial distribution of geomorphic features, and to segment each of these features based on relative hydrostratigraphic differences. A digital elevation model (DEM) dataset and predefined indices are used as inputs in a mountain watershed. The model uses periglacial, glacial, fluvial, slope evolution and lacustrine processes to identify regions that are subsequently delineated using morphometric principles. A 10 m cell size DEM from the headwaters of the St. Mary River watershed in Glacier National Park, Montana, was considered sufficient for this research. Morphometric parameters extracted from the DEM that were found to be useful for the calibration of the model were elevation, slope, flow direction, flow accumulation, and surface roughness. Algorithms were developed to utilize these parameters and delineate the distributions of bedrock outcrops, periglacial landscapes, alluvial channels, fans and outwash plains, glacial depositional features, talus slopes, and other mass wasted material. Theoretical differences in sedimentation and hydrofacies associated with each of the geomorphic features were used to segment the watershed into units reflecting similar hydrogeologic properties such as hydraulic conductivity and thickness. The results of the model were verified by comparing the distribution of geomorphic features with published geomorphic maps. Although agreement in semantics between datasets caused difficulties, a consensus yielded a comparison Dice Coefficient of 0

  13. Vernal Crater, SW Arabia Terra: MSL Candidate with Extensively Layered Sediments, Possible Lake Deposits, and a Long History of Subsurface Ice

    NASA Technical Reports Server (NTRS)

    Oehler, Dorothy Z.; Allen, Carlton C.

    2007-01-01

    Vernal Crater is a Mars Science Laboratory (MSL) landing site candidate providing relatively easy access to extensively layered sediments as well as potential lake deposits. Sediments of Vernal Crater are 400-1200 m below those being investigated by Opportunity in Meridiani Planum, and as such would allow study of significantly older geologic units, if Vernal Crater were selected for MSL. The location of Vernal Crater in SW Arabia Terra provides exceptional scientific interest, as rampart craters and gamma-ray spectrometer (GRS) data from the region suggest a long history of ice/fluids in the subsurface. The potential value of this MSL candidate is further enhanced by reports of atmospheric methane over Arabia, as any insight into the source of that methane would significantly increase our understanding of Mars. Finally, should MSL survive beyond its prime mission, the gentle slope within Vernal Crater would provide a route out of the crater for study of the once ice/fluid-rich plains.

  14. Porosity and Organic Carbon Controls on Naturally Reduced Zone (NRZ) Formation Creating Microbial ';Hotspots' for Fe, S, and U Cycling in Subsurface Sediments

    NASA Astrophysics Data System (ADS)

    Jones, M. E.; Janot, N.; Bargar, J.; Fendorf, S. E.

    2013-12-01

    Previous studies have illustrated the importance of Naturally Reduced Zones (NRZs) within saturated sediments for the cycling of metals and redox sensitive contaminants. NRZs can provide a source of reducing equivalents such as reduced organic compounds or hydrogen to stimulate subsurface microbial communities. These NRZ's are typically characterized by low permeability and elevated concentrations of organic carbon and trace metals. However, both the formation of NRZs and their importance to the overall aquifer carbon remineralization is not fully understood. Within NRZs the hydrolysis of particulate organic carbon (POC) and subsequent fermentation of dissolved organic carbon (DOC) to form low molecular weight dissolved organic carbon (LMW-DOC) provides electron donors necessary for the respiration of Fe, S, and in the case of the Rifle aquifer, U. Rates of POC hydrolysis and subsequent fermentation have been poorly constrained and rates in excess and deficit to the rates of subsurface anaerobic respiratory processes have been suggested. In this study, we simulate the development of NRZ sediments in diffusion-limited aggregates to investigate the physical and chemical conditions required for NRZ formation. Effects of sediment porosity and POC loading on Fe, S, and U cycling on molecular and nanoscale are investigated with synchrotron-based Near Edge X-ray Absorption Fine Structure Spectroscopy (NEXAFS). Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and Fourier Transform Infrared spectroscopy (FTIR) are used to characterize the transformations in POC and DOC. Sediment aggregates are inoculated with the natural microbial biota from the Rifle aquifer and population dynamics are monitored by 16S RNA analysis. Overall, establishment of low permeability NRZs within the aquifer stimulate microbial respiration beyond the diffusion-limited zones and can limit the transport of U through a contaminated aquifer. However, the long-term stability of

  15. In situ redox manipulation of subsurface sediments from Fort Lewis, Washington: Iron reduction and TCE dechlorination mechanisms

    SciTech Connect

    JE Szecsody; JS Fruchter; DS Sklarew; JC Evans

    2000-03-21

    Pacific Northwest National Laboratory (PNNL) conducted a bench-scale study to determine how effective chemically treated Ft. Lewis sediments can degrade trichloroethylene (TCE). The objectives of this experimental study were to quantify: (1) sediment reduction and oxidation reactions, (2) TCE degradation reactions, and (3) other significant geochemical changes that occurred. Sediment reduction and oxidation were investigated to determine the mass of reducible iron in the Ft. Lewis sediments and the rate of this reduction and subsequent oxidation at different temperatures. The temperature dependence was needed to be able to predict field-scale reduction in the relatively cold ({approximately}11 C) Ft. Lewis aquifer. Results of these experiments were used in conjunction with other geochemical and hydraulic characterization to design the field-scale injection experiment and predict barrier longevity. For example, the sediment reduction rate controls the amount of time required for the dithionite solution to fully react with sediments. Sediment oxidation experiments were additionally conducted to determine the oxidation rate and provide a separate measure of the mass of reduced iron. Laboratory experiments that were used to meet these objectives included: (1) sediment reduction in batch (static) systems, (2) sediment reduction in 1-D columns, and (3) sediment oxidation in 1-D columns. Multiple reaction modeling was conducted to quantify the reactant masses and reaction rates.

  16. Diversity, abundance, and distribution of NO-forming nitrite reductase-encoding genes in deep-sea subsurface sediments of the South China Sea.

    PubMed

    Li, M; Hong, Y; Cao, H; Klotz, M G; Gu, J-D

    2013-03-01

    In marine ecosystems, both nitrite-reducing bacteria and anaerobic ammonium-oxidizing (anammox) bacteria, containing different types of NO-forming nitrite reductase-encoding genes, contribute to the nitrogen cycle. The objectives of study were to reveal the diversity, abundance, and distribution of NO-forming nitrite reductase-encoding genes in deep-sea subsurface environments. Results showed that higher diversity and abundance of nirS gene than nirK and Scalindua-nirS genes were evident in the sediments of the South China Sea (SCS), indicating bacteria containing nirS gene dominated the NO-forming nitrite-reducing microbial community in this ecosystem. Similar diversity and abundance distribution patterns of both nirS and Scalindua-nirS genes were detected in this study sites, but different from nirK gene. Further statistical analyses also showed both nirS and Scalindua-nirS genes respond similarly to environmental factors, but differed from nirK gene. These results suggest that bacteria containing nirS and Scalindua-nirS genes share similar niche in deep-sea subsurface sediments of the SCS, but differed from those containing nirK gene, indicating that community structures of nitrite-reducing bacteria are segregated by the functional modules (NirS vs. NirK) rather than the competing processes (anammox vs. classical denitrification).

  17. In-depth analyses of deep subsurface sediments using 454-pyrosequencing reveals a reservoir of buried fungal communities at record-breaking depths.

    PubMed

    Rédou, Vanessa; Ciobanu, Maria Cristina; Pachiadaki, Maria G; Edgcomb, Virginia; Alain, Karine; Barbier, Georges; Burgaud, Gaëtan

    2014-12-01

    The deep subseafloor, extending from a few centimeters below the sediment surface to several hundred meters into sedimentary deposits, constitutes the deep biosphere and harbors an unexpected microbial diversity. Several studies have described the occurrence, turnover, activity and function of subseafloor prokaryotes; however, subsurface eukaryotic communities still remain largely underexplored. Ribosomal RNA surveys of superficial and near-surface marine sediments have revealed an unexpected diversity of active eukaryotic communities, but knowledge of the diversity of deep subseafloor microeukaryotes is still scarce. Here, we investigated the vertical distribution of DNA and RNA fungal signatures within subseafloor sediments of the Canterbury basin (New Zealand) by 454 pyrotag sequencing of fungal genetic markers. Different shifts between the fungal classes of Tremellomycetes, Sordariomycetes, Eurotiomycetes, Saccharomycetes, Wallemiomycetes, Dothideomycetes, Exobasidiomycetes and Microbotryomycetes were observed. These data provide direct evidence that fungal communities occur at record depths in deep sediments of the Canterbury basin and extend the depth limit of fungal presence and activity, respectively 1740 and 346 mbsf. As most of the fungal sequences retrieved have a cosmopolitan distribution, it indicates that fungi are able to adapt to the deep subseafloor conditions at record-depth and must play important ecological roles in biogeochemical cycles.

  18. Interstitial fluid chemistry of sediments underlying the North Atlantic gyre and the influence of subsurface fluid flow

    NASA Astrophysics Data System (ADS)

    Ziebis, Wiebke; McManus, James; Ferdelman, Timothy; Schmidt-Schierhorn, Friederike; Bach, Wolfgang; Muratli, Jesse; Edwards, Katrina J.; Villinger, Heinrich

    2012-03-01

    The western flank of the Mid-Atlantic Ridge is a region underlying the oligotrophic waters of the central Atlantic. The seafloor along portions of this ridge is characterized by sediment-filled depressions, which are surrounded by steep basaltic outcrops. We present pore fluid and sediment solid-phase chemical data from fourteen gravity cores from "North Pond", a sediment pond where previous drilling work indicated directed flow of seawater within the basement. Sediment lithology is broadly characterized as a nannofossil pelagic sediment containing varying amounts of clay, foraminifers, and Mn-micronodules and typically contains less than 0.3% organic carbon and ~ 70% calcium carbonate. Consistent with its location within an oligotrophic ocean gyre, oxygen and nitrate penetrated deeply into the sediment package. However there is significant spatial variability in the pore fluid nitrate and oxygen profiles, with oxygen generally lower and nitrate higher toward the center of the basin as compared to the edges. In addition, oxygen increased with sediment depth at a number of sites toward the edges of the pond, where sediment cover was thinnest. We interpret these oxygen distributions to indicate that there is upward diffusion of dissolved oxygen from the underlying basaltic basement fluid and the sediment package, and this process appears to be regionally pervasive. Pore fluid molybdenum generally decreases with depth and exhibits spatial variability similar to dissolved oxygen and nitrate. Molybdenum is likely being taken up at depth via adsorption onto manganese oxides, as these sediments are rich in manganese (~ 300-3000 ppm Mn) and molybdenum (~ 2-14 ppm Mo). The strong geographical variations in pore fluid chemistry coupled with the co-variation between molybdenum and oxygen, two species that we would not necessarily expect to be coupled, suggest that diffusion of dissolved constituents into the sediment package from below plays an important role in determining

  19. In Situ Redox Manipulation of Subsurface Sediments from Fort Lewis, Washington: Iron Reduction and TCE Dechlorination Mechanisms

    SciTech Connect

    Szecsody, James E.; Fruchter, Jonathan S.; Sklarew, Deborah S.; Evans, John C.

    2000-03-17

    The feasibility of chemically treating sediments from the Ft. Lewis, Washington, Logistics Center to develop a permeable barrier for dechlorination of TCE was investigated in a series of laboratory experiments.

  20. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    SciTech Connect

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2015-09-28

    The additivity model assumed that field-scale reaction properties in a sediment including surface area, reactive site concentration, and reaction rate can be predicted from field-scale grain-size distribution by linearly adding reaction properties estimated in laboratory for individual grain-size fractions. This study evaluated the additivity model in scaling mass transfer-limited, multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of the rate constants for individual grain-size fractions, which were then used to predict rate-limited U(VI) desorption in the composite sediment. The result indicated that the additivity model with respect to the rate of U(VI) desorption provided a good prediction of U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel-size fraction (2 to 8 mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  1. The importance of subsurface nepheloid layers in transport and delivery of sediments to the eastern Cariaco Basin, Venezuela

    NASA Astrophysics Data System (ADS)

    Lorenzoni, Laura; Thunell, Robert C.; Benitez-Nelson, Claudia R.; Hollander, David; Martinez, Nahysa; Tappa, Eric; Varela, Ramón; Astor, Yrene; Muller-Karger, Frank E.

    2009-12-01

    Optical transmissometer measurements were coupled with particulate organic matter (POM) observations to understand suspended sediment composition and distribution in the eastern Cariaco Basin during the rainy seasons of September 2003 and 2006. Our results suggest that nepheloid layers originating at the mouth of small mountainous rivers discharging into the eastern Basin are a major delivery mechanism of terrigenous sediments to the Basin interior. Intermediate nepheloid layers (INL) were observed near the shelf break (˜100 m) and appear to effectively transport terrigenous material laterally from the shelf to deep waters, thereby providing a plausible supply mechanism of the terrestrial material observed in sediment traps. These findings highlight the importance of small, local rivers in the Cariaco Basin as sources of terrestrial material. In contrast, these nepheloid layers contained only limited POM. When this information is combined with published sediment trap POM data, it suggests that nepheloid layers may not be a primary mechanism for delivering terrigenous POM to the deeper waters of the basin during the rainy season. Rather, BNL may redistribute marine-derived POM from shallow waters to the Basin's interior by providing ballast materials, particularly during episodic events driven by wind and precipitation. Though we have determined that nepheloid layers play an important role in the seaward transport of particulate material in the Cariaco Basin, their composition and temporal variability have not been fully characterized. This is critical to understand lateral particle transport, since nepheloid layers constitute a significant source of sediment to the deep Cariaco Basin.

  2. Recruitment and expression of toluene/trichloroethylene biodegradation genes in bacteria native to deep-subsurface sediments

    SciTech Connect

    Romine, M.F.; Brockman, F.J.

    1996-07-01

    Four plasmids, each encoding a combination of either an Escherichia coli or Pseudomonas putida promoter and either toluene dioxygenase or toluene monooxygenase, were electroporated into five bacterial strains isolated from sediments found at depths of 91 to 295 m. Four of these engineered bacterial strains demonstrated both toluene and trichloroethylene degradation activities. 26 refs., 2 tabs.

  3. Grain-Size Based Additivity Models for Scaling Multi-rate Uranyl Surface Complexation in Subsurface Sediments

    SciTech Connect

    Zhang, Xiaoying; Liu, Chongxuan; Hu, Bill X.; Hu, Qinhong

    2015-09-28

    This study statistically analyzed a grain-size based additivity model that has been proposed to scale reaction rates and parameters from laboratory to field. The additivity model assumed that reaction properties in a sediment including surface area, reactive site concentration, reaction rate, and extent can be predicted from field-scale grain size distribution by linearly adding reaction properties for individual grain size fractions. This study focused on the statistical analysis of the additivity model with respect to reaction rate constants using multi-rate uranyl (U(VI)) surface complexation reactions in a contaminated sediment as an example. Experimental data of rate-limited U(VI) desorption in a stirred flow-cell reactor were used to estimate the statistical properties of multi-rate parameters for individual grain size fractions. The statistical properties of the rate constants for the individual grain size fractions were then used to analyze the statistical properties of the additivity model to predict rate-limited U(VI) desorption in the composite sediment, and to evaluate the relative importance of individual grain size fractions to the overall U(VI) desorption. The result indicated that the additivity model provided a good prediction of the U(VI) desorption in the composite sediment. However, the rate constants were not directly scalable using the additivity model, and U(VI) desorption in individual grain size fractions have to be simulated in order to apply the additivity model. An approximate additivity model for directly scaling rate constants was subsequently proposed and evaluated. The result found that the approximate model provided a good prediction of the experimental results within statistical uncertainty. This study also found that a gravel size fraction (2-8mm), which is often ignored in modeling U(VI) sorption and desorption, is statistically significant to the U(VI) desorption in the sediment.

  4. The effect of biogenic Fe(II) on the stability and sorption of Co(II)EDTA{sup 2{minus}} to goethite and a subsurface sediment

    SciTech Connect

    Zachara, J.M.; Smith, S.C.; Fredrickson, J.K.

    2000-04-01

    Laboratory experiments were conducted with suspensions of goethite ({alpha}-FeOOH) and a subsurface sediment to assess the influence of bacterial iron reduction on the fate of Co(II)EDTA{sup 2{minus}}, a representative metal-ligand complex of intermediate stability (log K{sub Co(II)EDTA} = 17.97). The goethite was synthetic (ca. 55 m{sup 2}/g) and the sediment was a Pleistocene age, Fe(III) oxide-containing material from the Atlantic coastal plain (Milford). Shewanella alga strain BrY, a dissimulatory iron reducing bacterium (DIRB), was used to promote Fe(III) oxide reduction. Sorption isotherms and pH adsorption edges were measured for Co{sup 2+}, Fe{sup 2+}, Co(II)EDTA{sup 2{minus}}, and Fe(II)EDTA{sup 2{minus}} on the two sorbents in 0.001 mol/L Ca(ClO{sub 4}){sub 2} to aid in experiment interpretation. It is concluded that cationic radionuclides such as {sup 60}Co or {sup 239/240}Pu, which may be mobilized from disposed wastes by complexation with EDTA{sup 4{minus}}, may become immobilized in groundwater zones where dissimilatory bacterial iron reduction is operative.

  5. Isotopic composition of dissolved inorganic carbon in subsurface sediments of gas hydrate-bearing mud volcanoes, Lake Baikal: implications for methane and carbonate origin

    NASA Astrophysics Data System (ADS)

    Krylov, Alexey A.; Khlystov, Oleg M.; Hachikubo, Akihiro; Minami, Hirotsugu; Nunokawa, Yutaka; Shoji, Hitoshi; Zemskaya, Tamara I.; Naudts, Lieven; Pogodaeva, Tatyana V.; Kida, Masato; Kalmychkov, Gennady V.; Poort, Jeffrey

    2010-06-01

    We report on the isotopic composition of dissolved inorganic carbon (DIC) in pore-water samples recovered by gravity coring from near-bottom sediments at gas hydrate-bearing mud volcanoes/gas flares (Malenky, Peschanka, Peschanka 2, Goloustnoe, and Irkutsk) in the Southern Basin of Lake Baikal. The δ13C values of DIC become heavier with increasing subbottom depth, and vary between -9.5 and +21.4‰ PDB. Enrichment of DIC in 13C indicates active methane generation in anaerobic environments near the lake bottom. These data confirm our previous assumption that crystallization of carbonates (siderites) in subsurface sediments is a result of methane generation. Types of methanogenesis (microbial methyl-type fermentation versus CO2-reduction) were revealed by determining the offset of δ13C between dissolved CH4 and CO2, and also by using δ13C and δD values of dissolved methane present in the pore waters. Results show that both mechanisms are most likely responsible for methane generation at the investigated locations.

  6. Subsurface fluids from basement basalt of the Juan de Fuca Ridge possess microbial communities that are distinct from overlying sediments and surrounding seawater

    NASA Astrophysics Data System (ADS)

    Jungbluth, S.; Bowers, R. M.; Lin, H.; Hsieh, C.; Cowen, J. P.; Rappe, M. S.

    2013-12-01

    Hydrothermal circulation of fluids through the porous and permeable ocean basement fuels a deep subsurface microbial community that remains poorly characterized due to the logistical and methodological constraints associated with sampling the sediment-covered seafloor. Ocean Drilling Program and Integrated Ocean Drilling Program holes penetrating 1.2-3.5 million-years old sediment-covered basaltic crust of the Juan de Fuca Ridge flank fitted with Circulation Obviation Retrofit Kit (CORK) borehole observatories have enabled sampling of chemically-reducing basement fluids over the course of multiple years (2008-2013). Consistent and reliable access to pristine fluids from the ocean crust is due to improvements to CORK observatories, through incorporation of microbiologically-friendly materials, and fluid sampling techniques and equipment. By analyzing ~1.7 million reads of the small subunit ribosomal RNA (SSU rRNA) gene by next-generation Illumina sequencing from marine sediment, deep seawater, and 24 crustal fluid samples spanning multiple years and boreholes (1025C, U1301A, U1362A, and U1362), a distinct subseafloor biosphere dominated by the domain Bacteria was uncovered. Fluids from borehole U1301A sampled annually over the course of three years each had distinct microbial community structure and were dominated by the Proteobacteria. In contrast, fluids from boreholes 1362A and 1362B, located ~500 meters to the northeast, contained lineages phylogenetically related to the phylum Nitrospirae in highest abundance. The domain Archaea was was dominated by either the phylum Crenarchaeota (borehole U1301A) or the Euryarchaeota (boreholes 1025C, U1362A and U1362B). SSU rRNA genes phylogenetically affiliated with known lineages of methane producing Euryarchaeota (e.g. Methanobacteria) were the most abundant archaeal group detected in fluids from Holes U1362A and U1362B, predominantly within samples originating from the deepest subsurface sampling horizon (~200 meters sub

  7. H(2)-CO(2)-Dependent Anaerobic O-Demethylation Activity in Subsurface Sediments and by an Isolated Bacterium.

    PubMed

    Liu, S; Suflita, J M

    1993-05-01

    The ability of microorganisms in sediments from the Atlantic Coastal Plain to biodegrade methoxylated aromatic compounds was examined. O-demethylation activity was detected in deep (121- and 406-m) sediments, as well as in the surface soil. A syringate-demethylating consortium, containing at least three types of bacteria, was enriched from a deep-sediment sample in a medium containing syringate as the sole organic carbon source and with a N(2)-CO(2) atmosphere. An isolate which demethylated syringate was obtained from the enrichment on an agar medium incubated under a H(2)-CO(2) but not a N(2)-CO(2) or N(2) atmosphere. O demethylation of syringate of this isolate was dependent on the presence of both H(2) and CO(2) in the gas phase. The metabolism of syringate occurred in a sequential manner: methylgallate accumulated transiently before it was converted to gallate. Mass balance analysis suggests that the stoichiometry of the reaction in this isolate proceeds in accordance with the following generalized equation: C(7)H(3)O(3)(OCH(3))(n) + nHCO(3) + nH(2) --> C(7)H(3)O(3)(OH)(n) + nCH(3)COO + nH(2)O.

  8. Uranium (VI) Sorption and Transport in Unsaturated, Subsurface Hanford Site Sediments - Effect of Moisture Content and Sediment Texture: Final Report for Subtask 2b

    SciTech Connect

    Gamerdinger, A.P.; Resch, C.T.; Kaplan, D.I.

    1998-11-24

    A series of experiments were conducted in fiscal year 1998 at the Pacific Northwest National Laboratory as part of the Immobilized Low-Activity Waste-Performance Assessment. These experiments evaluated the sorption and transport of uranium, U(VI), under conditions of partial moisture saturation that are relevant to arid region burial sites and vadose-zone far-field conditions at the Hanford Site. The focus was on measuring breakthrough curves (from which distribution coefficient [K{sub d}] values can be calculated) for U(W) in three Hanford Site sediments that represent different texture classes in two unsaturated moisture conditions. Previous research showed that K{sub d} values measured during transport in unsaturated sediments varied with moisture saturation.

  9. The Effect of mining and related activities on the sediment-trace element geochemistry of Lake Coeur d'Alene, Idaho, U.S.A.; Part II, Subsurface sediments

    USGS Publications Warehouse

    Horowitz, A.J.; Elrick, K.A.; Robbins, J.A.; Cook, R.B.

    1993-01-01

    During the summer of 1990, 12 gravity cores were collected in Lake Coeur d'Alene, Idaho, at various depths and in a variety of depositional environments. All core subsamples were analyzed to determine bulk chemistry and selected subsamples were analyzed for trace-element partitioning and (137)Cs activity. The purpose of these analyses was to determine the trace-element concentrations and distributions in the sediment column and to try to establish a trace-element geochemical history of the lake in relation to mining and mining-related discharge operations in the area. Substantial portions of the near-surface sediments in Lake Coeur d'Alene are markedly enriched in Ag, As, Cd, Hg, Pb, Sb, and Zn, and somewhat enriched in Cu, Fe, and Mn. Variations in the thickness of the trace element- rich sediments suggest that the source of much of this material is the Coeur d'Alene River. Calculated estimates indicate that there are some 75 million metric tons of trace element-rich sediments currently on/in the lakebed. Estimated trace-element masses in excess of those caused by non-mining-related sources, range from a high of 468,000 metric tons of Pb to a low of 260 metric tons of Hg. The similarity between the trace element-rich surface and subsurface sediments as regards their: (1) location; (2) bulk chemistry; (3) interelement relationships; and (4) trace-element partitioning indicate that the sources and/or concentrating mechanisms causing the trace-element enrichment in the lake probably have been the same throughout their depositional history. Based on Mt. St. Helens' ash layer from the 1980 eruption, ages estimated from (137)Cs activity, and the presence of 80 discernible and presumably annual layers in a core collected near the Coeur d'Alene River delta, it appears that deposition rates for the trace element-rich sediments varied from 2.1 to 1.3 cm/yr. These data also indicate that the deposition of trace element-rich sediments began, at least in the Coeur d

  10. DOE ER63951-3 Final Report: An Integrated Assessment of Geochemical and Community Structure Determinants of Metal Reduction Rates in Subsurface Sediments

    SciTech Connect

    Susan Pfiffner

    2010-06-28

    The objective of this research was to examine the importance of microbial community structure in influencing uranium reduction rates in subsurface sediments. If the redox state alone is the key to metal reduction, then any organisms that can utilize the oxygen and nitrate in the subsurface can change the geochemical conditions so metal reduction becomes an energetically favored reaction. Thus, community structure would not be critical in determining rates or extent of metal reduction unless community structure influenced the rate of change in redox. Alternatively, some microbes may directly catalyze metal reduction (e.g., specifically reduce U). In this case the composition of the community may be more important and specific types of electron donors may promote the production of communities that are more adept at U reduction. Our results helped determine if the type of electron donor or the preexisting community is important in the bioremediation of metal-contaminated environments subjected to biostimulation. In a series of experiments at the DOE FRC site in Oak Ridge we have consistently shown that all substrates promoted nitrate reduction, while glucose, ethanol, and acetate always promoted U reduction. Methanol only occasionally promoted extensive U reduction which is possibly due to community heterogeneity. There appeared to be limitations imposed on the community related to some substrates (e.g. methanol and pyruvate). Membrane lipid analyses (phospholipids and respiratory quinones) indicated different communities depending on electron donor used. Terminal restriction fragment length polymorphism and clone libraries indicated distinct differences among communities even in treatments that promoted U reduction. Thus, there was enough metabolic diversity to accommodate many different electron donors resulting in the U bioimmobilization.

  11. Deep subsurface microbial processes

    USGS Publications Warehouse

    Lovley, D.R.; Chapelle, F.H.

    1995-01-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

  12. The effect of biogenic Fe(II) on the stability and sorption of Co(II)EDTA 2- to goethite and a subsurface sediment

    NASA Astrophysics Data System (ADS)

    Zachara, John M.; Smith, Steven C.; Fredrickson, James K.

    2000-04-01

    Laboratory experiments were conducted with suspensions of goethite (α-FeOOH) and a subsurface sediment to assess the influence of bacterial iron reduction on the fate of Co(II)EDTA 2-, a representative metal-ligand complex of intermediate stability (log K Co(II)EDTA = 17.97). The goethite was synthetic (ca. 55 m 2/g) and the sediment was a Pleistocene age, Fe(III) oxide-containing material from the Atlantic coastal plain (Milford). Shewanella alga strain BrY, a dissimilatory iron reducing bacterium (DIRB), was used to promote Fe(III) oxide reduction. Sorption isotherms and pH adsorption edges were measured for Co 2+, Fe 2+, Co(II)EDTA 2-, and Fe(II)EDTA 2- on the two sorbents in 0.001 mol/L Ca(ClO 4) 2 to aid in experiment interpretation. Anoxic suspensions of the sorbents in PIPES buffer at pH 6.5-7.0 were spiked with Co(II)EDTA 2- (10 -5 mol/L, 60Co and 14EDTA labeled), inoculated with BrY (1-6 × 10 8 organisms/mL), and the headspace filled with a N 2/H 2 gas mix. The experiments were conducted under non-growth conditions. The medium did not contain PO 43- (with one exception), trace elements, or vitamins. The tubes were incubated under anoxic conditions at 25°C for time periods in excess of 100 d. Replicate tubes were sacrificed and analyzed at desired time periods for pH, Fe(II) TOT, Fe (aq)2+, 60Co, and 14EDTA. Abiotic analogue experiments were conducted where Fe (aq)2+ was added in increasing concentration to Co(II)EDTA 2-/mineral suspensions to simulate the influence of bacterial Fe(II) evolution. The DIRB generated Fe(II) from both goethite and the Milford sediment that was strongly sorbed by mineral surfaces. Aqueous Fe 2+ increased during the experiment as surfaces became saturated; Fe (aq)2+ induced the dissociation of Co(II)EDTA 2- into a mixture of Co 2+, Co(II)EDTA 2-, and Fe(II)EDTA 2- (log K Fe(II)EDTA = 15.98). The extent of dissociation of Co(II)EDTA 2- was greater in the subsurface sediment because it sorbed Fe(II) less strongly than did

  13. Keep your Sox on: Community genomics-directed isolation and microscopic characterization of the dominant subsurface sulfur-oxidizing bacterium in a sediment aquifer

    NASA Astrophysics Data System (ADS)

    Mullin, S. W.; Wrighton, K. C.; Luef, B.; Wilkins, M. J.; Handley, K. M.; Williams, K. H.; Banfield, J. F.

    2012-12-01

    Community genomics and proteomics (proteogenomics) can be used to predict the metabolic potential of complex microbial communities and provide insight into microbial activity and nutrient cycling in situ. Inferences regarding the physiology of specific organisms then can guide isolation efforts, which, if successful, can yield strains that can be metabolically and structurally characterized to further test metagenomic predictions. Here we used proteogenomic data from an acetate-stimulated, sulfidic sediment column deployed in a groundwater well in Rifle, CO to direct laboratory amendment experiments to isolate a bacterial strain potentially involved in sulfur oxidation for physiological and microscopic characterization (Handley et al, submitted 2012). Field strains of Sulfurovum (genome r9c2) were predicted to be capable of CO2 fixation via the reverse TCA cycle and sulfur oxidation (Sox and SQR) coupled to either nitrate reduction (Nap, Nir, Nos) in anaerobic environments or oxygen reduction in microaerobic (cbb3 and bd oxidases) environments; however, key genes for sulfur oxidation (soxXAB) were not identified. Sulfidic groundwater and sediment from the Rifle site were used to inoculate cultures that contained various sulfur species, with and without nitrate and oxygen. We isolated a bacterium, Sulfurovum sp. OBA, whose 16S rRNA gene shares 99.8 % identity to the gene of the dominant genomically characterized strain (genome r9c2) in the Rifle sediment column. The 16S rRNA gene of the isolate most closely matches (95 % sequence identity) the gene of Sulfurovum sp. NBC37-1, a genome-sequenced deep-sea sulfur oxidizer. Strain OBA grew via polysulfide, colloidal sulfur, and tetrathionate oxidation coupled to nitrate reduction under autotrophic and mixotrophic conditions. Strain OBA also grew heterotrophically, oxidizing glucose, fructose, mannose, and maltose with nitrate as an electron acceptor. Over the range of oxygen concentrations tested, strain OBA was not

  14. Short-read assembly of full-length 16S amplicons reveals bacterial diversity in subsurface sediments.

    PubMed

    Miller, Christopher S; Handley, Kim M; Wrighton, Kelly C; Frischkorn, Kyle R; Thomas, Brian C; Banfield, Jillian F

    2013-01-01

    In microbial ecology, a fundamental question relates to how community diversity and composition change in response to perturbation. Most studies have had limited ability to deeply sample community structure (e.g. Sanger-sequenced 16S rRNA libraries), or have had limited taxonomic resolution (e.g. studies based on 16S rRNA hypervariable region sequencing). Here, we combine the higher taxonomic resolution of near-full-length 16S rRNA gene amplicons with the economics and sensitivity of short-read sequencing to assay the abundance and identity of organisms that represent as little as 0.01% of sediment bacterial communities. We used a new version of EMIRGE optimized for large data size to reconstruct near-full-length 16S rRNA genes from amplicons sheared and sequenced with Illumina technology. The approach allowed us to differentiate the community composition among samples acquired before perturbation, after acetate amendment shifted the predominant metabolism to iron reduction, and once sulfate reduction began. Results were highly reproducible across technical replicates, and identified specific taxa that responded to the perturbation. All samples contain very high alpha diversity and abundant organisms from phyla without cultivated representatives. Surprisingly, at the time points measured, there was no strong loss of evenness, despite the selective pressure of acetate amendment and change in the terminal electron accepting process. However, community membership was altered significantly. The method allows for sensitive, accurate profiling of the "long tail" of low abundance organisms that exist in many microbial communities, and can resolve population dynamics in response to environmental change.

  15. Characteristics of the surface-subsurface flow generation and sediment yield to the rainfall regime and land-cover by long-term in-situ observation in the red soil region, Southern China

    NASA Astrophysics Data System (ADS)

    Liu, Yao-Jun; Yang, Jie; Hu, Jian-Min; Tang, Chong-Jun; Zheng, Hai-Jin

    2016-08-01

    Land cover and rainfall regime are two important factors that affect soil erosion. In this paper, three land cover types - grass cover, litter cover and bare land - were employed to analyze surface runoff, subsurface flow and sediment loss processes in relation to the rainfall regimes in the red soil region of China. Five rainfall regimes were classified according to 393 rainfall events via a k-means clustering method based on the rainfall depth, duration and maximum 30-min intensity. The highest surface runoff coefficient and erosion amount were found on bare land in all five rainfall regimes, and the lowest were found on grass cover. The litter cover generated the highest subsurface flow rate, followed by the grass cover; the lowest was on bare land. For grass cover and litter cover plots, rainfall events of rainfall regime IV which had the longest duration, greatest depth and lowest intensity had the highest surface runoff coefficient, soil erosion amount and subsurface flow rate. For bare land, storm rainfall events of rainfall regime V had the highest intensity, lowest depth and duration, had the highest surface runoff coefficient and soil erosion amount, but the lowest subsurface flow rate. The highest subsurface flow rate of bare land happened in rainfall regime IV. Surface cover was urgently needed to reduce soil erosion. When the lands under dense surface cover, more attention should be paid to rainfall events that of long duration, high depth but low in intensity which commonly occurred in spring. The interactions of surface-subsurface flow and its effects on soil erosion and nutrient loss were worth considering in the red soil region.

  16. Terrestrial Subsurface Ecosystem

    SciTech Connect

    Wilkins, Michael J.; Fredrickson, Jim K.

    2015-10-15

    The Earth’s crust is a solid cool layer that overlays the mantle, with a varying thickness of between 30-50 km on continental plates, and 5-10 km on oceanic plates. Continental crust is composed of a variety of igneous, metamorphic, and sedimentary rocks that weather and re-form over geologic cycles lasting millions to billions of years. At the crust surface, these weathered minerals and organic material combine to produce a variety of soils types that provide suitable habitats and niches for abundant microbial diversity (see Chapter 4). Beneath this soil zone is the subsurface. Once thought to be relatively free of microorganisms, recent estimates have calculated that between 1016-1017 g C biomass (2-19% of Earth’s total biomass) may be present in this environment (Whitman et al., 1998;McMahon and Parnell, 2014). Microbial life in the subsurface exists across a wide range of habitats: in pores associated with relatively shallow unconsolidated aquifer sediments to fractures in bedrock formations that are more than a kilometer deep, where extreme lithostatic pressures and temperatures are encountered. While these different environments contain varying physical and chemical conditions, the absence of light is a constant. Despite this, diverse physiologies and metabolisms enable microorganisms to harness energy and carbon for growth in water-filled pore spaces and fractures. Carbon and other element cycles are driven by microbial activity, which has implications for both natural processes and human activities in the subsurface, e.g., bacteria play key roles in both hydrocarbon formation and degradation. Hydrocarbons are a major focus for human utilization of the subsurface, via oil and gas extraction and potential geologic CO2 sequestration. The subsurface is also utilized or being considered for sequestered storage of high-level radioactive waste from nuclear power generation and residual waste from past production of weapons grade nuclear materials. While our

  17. Subsurface sounders

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Airborne or spaceborne electromagnetic systems used to detect subsurface features are discussed. Data are given as a function of resistivity of ground material, magnetic permeability of free space, and angular frequency. It was noted that resistivities vary with the water content and temperature.

  18. Microbial activities in deep subsurface environments

    SciTech Connect

    Phelps, T.J.; Raione, E.G.; White, D.C. |; Fliermans, C.B.

    1988-12-31

    Activities of microorganisms residing in terrestrial deep subsurface sediments were examined in forty-six sediment samples from three aseptically sampled boreholes. Radiolabeled time course experiments assessing in situ microbial activities were initiated within 30 minutes of core recovery. [{sup 14}C-1-] Acetate incorporation into lipids. [methyl-{sup 3}H-]thymidine incorporation into DNA, [{sup 14}C-2-]acetate and [{sup 14}C-U-]glucose mineralization in addition to microbial enrichment and enumeration studies were examined in surface and subsurface sediments. Surface soils contained the greatest biomass and activities followed by the shallow aquifer zones. Water saturated subsurface sediments exhibited three to four orders of magnitude greater activity and culturable microorganisms than the dense clay zones. Regardless of depth, sediments which contained more than 20% clays exhibited the lowest activities and culturable microorganisms.

  19. Environmental factors affecting distribution and abundance of bacteria, fungi and protozoa in subsurface sediments of the Upper Atlantic Coastal Plain, USA

    SciTech Connect

    Levine, S.N.; Ghiorse, W.C.

    1990-01-01

    Exploratory statistical analyses of microbiological, hydrological and geochemical data for samples from four boreholes drilled into Upper Atlantic Coastal Plain sediments near the Savannah River Site, SC, showed highly significant correlations between bacterial abundance (AODC and CFU) and hydraulic conductivity (K). Sediment texture variables (% sand (S), % silt, % clay (C), and S/C) were strongly interrelated with K and, therefore, also correlated with bacterial abundance. AODC did not correlate with the concentrations of dissolved inorganic nitrogen (DIN) or dissolved organic carbon (DOC) in pore water. CFU also did not correlate with DIN, but a negative relationship was found between the CFU and DOC for sandy sediments, suggesting that microbial activity may control pore water DOC concentration. In some, but not all boreholes, AODC and CFU correlated negatively with pore water concentrations of metals and positively with pH. Protozoan abundance correlated strongly with AODC and CFU in the two boreholes closest to the recharge areas for their major aquifers. It also correlated with sediment texture variables, but not with K. Fungal abundance did not correlate with the abundance of other microbial types when data from individual boreholes were considered; however it did correlate with both bacterial and protozoan abundance when data from all four boreholes were combined. There was no relationship between fungal abundance and either K or sediment texture.

  20. Environmental factors affecting distribution and abundance of bacteria, fungi and protozoa in subsurface sediments of the Upper Atlantic Coastal Plain, USA

    SciTech Connect

    Levine, S.N.; Ghiorse, W.C.

    1990-12-31

    Exploratory statistical analyses of microbiological, hydrological and geochemical data for samples from four boreholes drilled into Upper Atlantic Coastal Plain sediments near the Savannah River Site, SC, showed highly significant correlations between bacterial abundance (AODC and CFU) and hydraulic conductivity (K). Sediment texture variables (% sand (S), % silt, % clay (C), and S/C) were strongly interrelated with K and, therefore, also correlated with bacterial abundance. AODC did not correlate with the concentrations of dissolved inorganic nitrogen (DIN) or dissolved organic carbon (DOC) in pore water. CFU also did not correlate with DIN, but a negative relationship was found between the CFU and DOC for sandy sediments, suggesting that microbial activity may control pore water DOC concentration. In some, but not all boreholes, AODC and CFU correlated negatively with pore water concentrations of metals and positively with pH. Protozoan abundance correlated strongly with AODC and CFU in the two boreholes closest to the recharge areas for their major aquifers. It also correlated with sediment texture variables, but not with K. Fungal abundance did not correlate with the abundance of other microbial types when data from individual boreholes were considered; however it did correlate with both bacterial and protozoan abundance when data from all four boreholes were combined. There was no relationship between fungal abundance and either K or sediment texture.

  1. An improved cell separation technique for marine subsurface sediments: applications for high-throughput analysis using flow cytometry and cell sorting

    PubMed Central

    Morono, Yuki; Terada, Takeshi; Kallmeyer, Jens; Inagaki, Fumio

    2013-01-01

    Summary Development of an improved technique for separating microbial cells from marine sediments and standardization of a high-throughput and discriminative cell enumeration method were conducted. We separated microbial cells from various types of marine sediment and then recovered the cells using multilayer density gradients of sodium polytungstate and/or Nycodenz, resulting in a notably higher percent recovery of cells than previous methods. The efficiency of cell extraction generally depends on the sediment depth; using the new technique we developed, more than 80% of the total cells were recovered from shallow sediment samples (down to 100 meters in depth), whereas ∼ 50% of cells were recovered from deep samples (100–365 m in depth). The separated cells could be rapidly enumerated using flow cytometry (FCM). The data were in good agreement with those obtained from manual microscopic direct counts over the range 104–108 cells cm−3. We also demonstrated that sedimentary microbial cells can be efficiently collected using a cell sorter. The combined use of our new cell separation and FCM/cell sorting techniques facilitates high-throughput and precise enumeration of microbial cells in sediments and is amenable to various types of single-cell analyses, thereby enhancing our understanding of microbial life in the largely uncharacterized deep subseafloor biosphere. PMID:23731283

  2. Tangible Exploration of Subsurface Data

    NASA Astrophysics Data System (ADS)

    Petrasova, A.; Harmon, B.; Mitasova, H.; White, J.

    2014-12-01

    Since traditional subsurface visualizations using 2D maps, profiles or charts can be difficult to interpret and often do not convey information in an engaging form, scientists are interested in developing alternative visualization techniques which would help them communicate the subsurface volume data with students and general public. We would like to present new technique for interactive visualization of subsurface using Tangible geospatial modeling and visualization system (Tangeoms). It couples a physical, three-dimensional model with geospatial modeling and analysis through a cycle of scanning and projection. Previous applications of Tangeoms were exploring the impact of terrain modifications on surface-based geophysical processes, such as overland water flow, sediment transport, and also on viewsheds, cast shadows or solar energy potential. However, Tangeoms can serve as a tool for exploring subsurface as well. By creating a physical sand model of a study area, removing the sand from different parts of the model and projecting the computed cross-sections, we can look under the ground as if we were at an excavation site, and see the actual data represented as a 3D raster in that particular part of the model. Depending on data availability, we can also incorporate temporal dimension. Our method is an intuitive and natural way of exploring subsurface data and for users, it represents an alternative to more abstract 3D computer visualization tools, by offering direct, tangible interface.

  3. Uranium interaction with soil minerals in the presence of co-contaminants: Case Study- subsurface sediments at or below the water table

    SciTech Connect

    Gartman, Brandy N.; Qafoku, Nikolla

    2016-03-09

    Uranium (U) contaminated subsurface systems are common on a global scale mainly because of its essential role in the production of plutonium for nuclear weapons and other nuclear energy and research activities. Studying the behavior and fate of U in these systems is challenging because of heterogeneities of different types (i.e., physical, chemical and mineralogical) and a complex network of often time-dependent hydrological, biological and chemical reactions and processes that occur sequentially or simultaneously, affecting and/or controlling U mobility. A U contaminated site, i.e., the Integrated Field Research Challenge site in Rifle, CO, USA (a former U mill site) is the focus of this discussion. The overall objectives of this chapter are to 1) provide an overview of the contamination levels (U and other co-contaminants) at this field site; 2) review and discuss different aspects of mineral-U contaminant interactions in reduced and oxidized environments, and in the presence of co-contaminants; 3) present results from a systematic macroscopic, microscopic, and spectroscopic study as an example of the current research efforts and the state-of-knowledge in this important research area; and 4) offer insightful conclusive remarks and future research needs about reactions and processes that control U and other contaminants’ fate and behavior under hydraulically saturated conditions. The implications and applications presented in this chapter are valid for U contaminated sites across the world.

  4. Rudimentary Cleaning Compared to Level 300A

    NASA Technical Reports Server (NTRS)

    Arpin, Christina Y. Pina; Stoltzfus, Joel

    2012-01-01

    A study was done to characterize the cleanliness level achievable when using a rudimentary cleaning process, and results were compared to JPR 5322.1G Level 300A. While it is not ideal to clean in a shop environment, some situations (e.g., field combat operations) require oxygen system hardware to be maintained and cleaned to prevent a fire hazard, even though it cannot be sent back to a precision cleaning facility. This study measured the effectiveness of basic shop cleaning. Initially, three items representing parts of an oxygen system were contaminated: a metal plate, valve body, and metal oxygen bottle. The contaminants chosen were those most likely to be introduced to the system during normal use: oil, lubricant, metal shavings/powder, sand, fingerprints, tape, lip balm, and hand lotion. The cleaning process used hot water, soap, various brushes, gaseous nitrogen, water nozzle, plastic trays, scouring pads, and a controlled shop environment. Test subjects were classified into three groups: technical professionals having an appreciation for oxygen hazards; professional precision cleaners; and a group with no previous professional knowledge of oxygen or precision cleaning. Three test subjects were in each group, and each was provided with standard cleaning equipment, a cleaning procedure, and one of each of the three test items to clean. The results indicated that the achievable cleanliness level was independent of the technical knowledge or proficiency of the personnel cleaning the items. Results also showed that achieving a Level 300 particle count was more difficult than achieving a Level A nonvolatile residue amount.

  5. 21 CFR 520.300a - Cambendazole suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Cambendazole suspension. 520.300a Section 520.300a Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.300a Cambendazole...

  6. Microscale geochemical gradients in Hanford 300 Area sediment biofilms and influence of uranium

    SciTech Connect

    Nguyen, Hung D.; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I.; Kemner, Kenneth M.; Fredrickson, Jim K.; Beyenal, Haluk

    2012-01-01

    The presence and importance of microenvironments in the subsurface at contaminated sites were suggested by previous geochemical studies. However, no direct quantitative characterization of the geochemical microenvironments had been reported. We quantitatively characterized microscale geochemical gradients (dissolved oxygen (DO), H(2), pH, and redox potential) in Hanford 300A subsurface sediment biofilms. Our results revealed significant differences in geochemical parameters across the sediment biofilm/water interface in the presence and absence of U(VI) under oxic and anoxic conditions. While the pH was relatively constant within the sediment biofilm, the redox potential and the DO and H(2) concentrations were heterogeneous at the microscale (<500-1000 μm). We found microenvironments with high DO levels (DO hotspots) when the sediment biofilm was exposed to U(VI). On the other hand, we found hotspots (high concentrations) of H(2) under anoxic conditions both in the presence and in the absence of U(VI). The presence of anoxic microenvironments inside the sediment biofilms suggests that U(VI) reduction proceeds under bulk oxic conditions. To test this, we operated our biofilm reactor under air-saturated conditions in the presence of U(VI) and characterized U speciation in the sediment biofilm. U L(III)-edge X-ray absorption spectroscopy (XANES and EXAFS) showed that 80-85% of the U was in the U(IV) valence state.

  7. Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments

    USGS Publications Warehouse

    Holmes, Dawn E.; O'Neil, Regina A.; Vrionis, Helen A.; N'Guessan, Lucie A.; Ortiz-Bernad, Irene; Larrahondo, Maria J.; Adams, Lorrie A.; Ward, Joy A.; Nicoll , Julie S.; Nevin, Kelly P.; Chavan, Milind A.; Johnson, Jessica P.; Long, Philip E.; Lovely, Derek R.

    2007-01-01

    There are distinct differences in the physiology of Geobacter species available in pure culture. Therefore, to understand the ecology of Geobacter species in subsurface environments, it is important to know which species predominate. Clone libraries were assembled with 16S rRNA genes and transcripts amplified from three subsurface environments in which Geobacter species are known to be important members of the microbial community: (1) a uranium-contaminated aquifer located in Rifle, CO, USA undergoing in situ bioremediation; (2) an acetate-impacted aquifer that serves as an analog for the long-term acetate amendments proposed for in situ uranium bioremediation and (3) a petroleum-contaminated aquifer in which Geobacter species play a role in the oxidation of aromatic hydrocarbons coupled with the reduction of Fe(III). The majority of Geobacteraceae 16S rRNA sequences found in these environments clustered in a phylogenetically coherent subsurface clade, which also contains a number of Geobacter species isolated from subsurface environments. Concatamers constructed with 43 Geobacter genes amplified from these sites also clustered within this subsurface clade. 16S rRNA transcript and gene sequences in the sediments and groundwater at the Rifle site were highly similar, suggesting that sampling groundwater via monitoring wells can recover the most active Geobacter species. These results suggest that further study of Geobacter species in the subsurface clade is necessary to accurately model the behavior of Geobacter species during subsurface bioremediation of metal and organic contaminants.

  8. Complete genome sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment

    DOE PAGES

    Hwang, C.; Copeland, A.; Lucas, Susan; ...

    2015-01-22

    We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium’s genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

  9. Electrical Subsurface Grounding Analysis

    SciTech Connect

    J.M. Calle

    2000-11-01

    The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements.

  10. Subsurface Microbiology and Biogeochemistry

    SciTech Connect

    Fredrickson, Jim K.; Fletcher, Madilyn

    2001-05-01

    Jim contributed a chapter to this book, in addition to co-editing it with Madilyn Fletcher. Fredrickson, J. K., and M. Fletcher. (eds.) 2001 Subsurface Microbiology and Biogeochemistry. Wiley-Liss, Inc., New York.

  11. Ceramic subsurface marker prototypes

    SciTech Connect

    Lukens, C.E.

    1985-05-02

    The client submitted 5 sets of porcelain and stoneware subsurface (radioactive site) marker prototypes (31 markers each set). The following were determined: compressive strength, thermal shock resistance, thermal crazing resistance, alkali resistance, color retention, and chemical resistance.

  12. Site Recommendation Subsurface Layout

    SciTech Connect

    C.L. Linden

    2000-06-28

    The purpose of this analysis is to develop a Subsurface Facility layout that is capable of accommodating the statutory capacity of 70,000 metric tons of uranium (MTU), as well as an option to expand the inventory capacity, if authorized, to 97,000 MTU. The layout configuration also requires a degree of flexibility to accommodate potential changes in site conditions or program requirements. The objective of this analysis is to provide a conceptual design of the Subsurface Facility sufficient to support the development of the Subsurface Facility System Description Document (CRWMS M&O 2000e) and the ''Emplacement Drift System Description Document'' (CRWMS M&O 2000i). As well, this analysis provides input to the Site Recommendation Consideration Report. The scope of this analysis includes: (1) Evaluation of the existing facilities and their integration into the Subsurface Facility design. (2) Identification and incorporation of factors influencing Subsurface Facility design, such as geological constraints, thermal loading, constructibility, subsurface ventilation, drainage control, radiological considerations, and the Test and Evaluation Facilities. (3) Development of a layout showing an available area in the primary area sufficient to support both the waste inventories and individual layouts showing the emplacement area required for 70,000 MTU and, if authorized, 97,000 MTU.

  13. Subsurface Contamination Control

    SciTech Connect

    Y. Yuan

    2001-12-12

    There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the subsurface repository; (2) provides a

  14. Subsurface Contamination Control

    SciTech Connect

    Y. Yuan

    2001-11-16

    There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the subsurface repository; (2) provides a

  15. Best Practice -- Subsurface Investigations

    SciTech Connect

    Clark Scott

    2010-03-01

    These best practices for Subsurface Survey processes were developed at the Idaho National Laboratory (INL) and later shared and formalized by a sub-committee, under the Electrical Safety Committee of EFCOG. The developed best practice is best characterized as a Tier II (enhanced) survey process for subsurface investigations. A result of this process has been an increase in the safety and lowering of overall cost, when utility hits and their related costs are factored in. The process involves improving the methodology and thoroughness of the survey and reporting processes; or improvement in tool use rather than in the tools themselves. It is hoped that the process described here can be implemented at other sites seeking to improve their Subsurface Investigation results with little upheaval to their existing system.

  16. The Serpentinite Subsurface Microbiome

    NASA Astrophysics Data System (ADS)

    Schrenk, M. O.; Nelson, B. Y.; Brazelton, W. J.

    2011-12-01

    Microbial habitats hosted in ultramafic rocks constitute substantial, globally-distributed portions of the subsurface biosphere, occurring both on the continents and beneath the seafloor. The aqueous alteration of ultramafics, in a process known as serpentinization, creates energy rich, high pH conditions, with low concentrations of inorganic carbon which place fundamental constraints upon microbial metabolism and physiology. Despite their importance, very few studies have attempted to directly access and quantify microbial activities and distributions in the serpentinite subsurface microbiome. We have initiated microbiological studies of subsurface seeps and rocks at three separate continental sites of serpentinization in Newfoundland, Italy, and California and compared these results to previous analyses of the Lost City field, near the Mid-Atlantic Ridge. In all cases, microbial cell densities in seep fluids are extremely low, ranging from approximately 100,000 to less than 1,000 cells per milliliter. Culture-independent analyses of 16S rRNA genes revealed low-diversity microbial communities related to Gram-positive Firmicutes and hydrogen-oxidizing bacteria. Interestingly, unlike Lost City, there has been little evidence for significant archaeal populations in the continental subsurface to date. Culturing studies at the sites yielded numerous alkaliphilic isolates on nutrient-rich agar and putative iron-reducing bacteria in anaerobic incubations, many of which are related to known alkaliphilic and subsurface isolates. Finally, metagenomic data reinforce the culturing results, indicating the presence of genes associated with organotrophy, hydrogen oxidation, and iron reduction in seep fluid samples. Our data provide insight into the lifestyles of serpentinite subsurface microbial populations and targets for future quantitative exploration using both biochemical and geochemical approaches.

  17. Subsurface Flow and Transport: A Stochastic Approach

    NASA Astrophysics Data System (ADS)

    Desbarats, Alexandre

    Anyone who has examined core or petrophysical logs from well bores has wondered at the rhythmic successions of sedimentary fades and has puzzled at their sudden disruption or reappearance. Such wonderment is no doubt shared by those who have stood at a quarry face gazing up at the intricate hierarchy of depositional patterns and the varied textures of sediments. A fortunate few have even slogged along a mine drift and observed at close hand the perplexing relationship between the geological fabric of a rock mass and occurrences of groundwater inflow. Happily, the heterogeneity of geological materials is now widely recognized and efforts over the last 20 years have been concerned with its incorporation into models of fluid flow and solute transport in the subsurface. These research efforts are, at least in part, driven by acute societal concerns over the contamination of groundwater resources and proposed plans for the disposal of nuclear and other toxic wastes in the subsurface.

  18. Active fungi amidst a marine subsurface RNA paleome

    NASA Astrophysics Data System (ADS)

    Orsi, W.; Biddle, J.; Edgcomb, V.

    2012-12-01

    The deep marine subsurface is a vast habitat for microbial life where cells may live on geologic timescales. Since extracellular DNA in sediments may be preserved on long timescales, ribosomal RNA (rRNA) is suggested to be a proxy for the active fraction of a microbial community in the subsurface. During an investigation of eukaryotic 18S rRNA signatures by amplicon pyrosequencing, metazoan, plant, and diatom rRNA signatures were recovered from marine sediments up to 2.7 million years old, suggesting that rRNA may be much more stable than previously considered in the marine subsurface. This finding confirms the concept of a paleome, extending it to include rRNA. Within the same dataset, unique profiles of fungi were found across a range of marine subsurface provinces exhibiting statistically significant correlations with total organic carbon (TOC), sulfide, and dissolved inorganic carbon (DIC). Sequences from metazoans, plants and diatoms showed different correlation patterns, consistent with a depth-controlled paleome. The fungal correlations with geochemistry allow the inference that some fungi are active and adapted for survival in the marine subsurface. A metatranscriptomic analysis of fungal derived mRNA confirms that fungi are metabolically active and utilize a range of organic and inorganic substrates in the marine subsurface.

  19. Subsurface connection methods for subsurface heaters

    DOEpatents

    Vinegar, Harold J.; Bass, Ronald Marshall; Kim, Dong Sub; Mason, Stanley Leroy; Stegemeier, George Leo; Keltner, Thomas Joseph; Carl, Jr., Frederick Gordon

    2010-12-28

    A system for heating a subsurface formation is described. The system includes a first elongated heater in a first opening in the formation. The first elongated heater includes an exposed metal section in a portion of the first opening. The portion is below a layer of the formation to be heated. The exposed metal section is exposed to the formation. A second elongated heater is in a second opening in the formation. The second opening connects to the first opening at or near the portion of the first opening below the layer to be heated. At least a portion of an exposed metal section of the second elongated heater is electrically coupled to at least a portion of the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated.

  20. Final Technical Report. Origins of subsurface microorganisms: Relating laboratory microcosm studies to a geologic time scale

    SciTech Connect

    Kieft, Thomas; Amy, Penny S.; Phillips, Fred M.

    1998-12-01

    This project was conducted as part of the Department of Energy's Deep Subsurface Science Program. It was part of a larger effort to determine the origins of subsurface microorganisms. Two hypotheses have been suggested for the origins of subsurface microorganisms: (1) microorganisms were deposited at the time of (or shortly after) geologic deposition of rocks and sediments (the in situ survival hypothesis), and (2) microorganisms have been transported from surface environments to subsurface rocks and sediments since the time of geologic deposition (transport hypothesis). These two hypotheses are not mutually exclusive. Depending on the geological setting, either one or both of these hypotheses may best explain microbial origins. Our project focused on the in situ survival hypothesis. We tested the hypothesis that microorganisms (individuals populations and communities) can survive long-term sequestration within subsurface sediments. Other objectives were to identify geologic conditions that favor long-term survival, identify physiological traits of microorganisms that favor long-term survival, and determine which groups of microorganisms are most likely to survive long-term sequestration in subsurface sediments. We tested this hypothesis using a combination of pure culture techniques in laboratory microcosms under controlled conditions and field experiments with buried subsurface sediments.

  1. Mars penetrator: Subsurface science mission

    NASA Technical Reports Server (NTRS)

    Lumpkin, C. K.

    1974-01-01

    A penetrator system to emplace subsurface science on the planet Mars is described. The need for subsurface science is discussed, and the technologies for achieving successful atmospheric entry, Mars penetration, and data retrieval are presented.

  2. Subsurface Ice Probe

    NASA Technical Reports Server (NTRS)

    Hecht, Michael; Carsey, Frank

    2005-01-01

    The subsurface ice probe (SIPR) is a proposed apparatus that would bore into ice to depths as great as hundreds of meters by melting the ice and pumping the samples of meltwater to the surface. Originally intended for use in exploration of subsurface ice on Mars and other remote planets, the SIPR could also be used on Earth as an alternative to coring, drilling, and melting apparatuses heretofore used to sample Arctic and Antarctic ice sheets. The SIPR would include an assembly of instrumentation and electronic control equipment at the surface, connected via a tether to a compact assembly of boring, sampling, and sensor equipment in the borehole (see figure). Placing as much equipment as possible at the surface would help to attain primary objectives of minimizing power consumption, sampling with high depth resolution, and unobstructed imaging of the borehole wall. To the degree to which these requirements would be satisfied, the SIPR would offer advantages over the aforementioned ice-probing systems.

  3. Subsurface contaminants focus area

    SciTech Connect

    1996-08-01

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

  4. Applications of subsurface microscopy.

    PubMed

    Tetard, Laurene; Passian, Ali; Farahi, Rubye H; Voy, Brynn H; Thundat, Thomas

    2012-01-01

    Exploring the interior of a cell is of tremendous importance in order to assess the effects of nanomaterials on biological systems. Outside of a controlled laboratory environment, nanomaterials will most likely not be conveniently labeled or tagged so that their translocation within a biological system cannot be easily identified and quantified. Ideally, the characterization of nanomaterials within a cell requires a nondestructive, label-free, and subsurface approach. Subsurface nanoscale imaging represents a real challenge for instrumentation. Indeed the tools available for high resolution characterization, including optical, electron or scanning probe microscopies, mainly provide topography images or require taggants that fluoresce. Although the intercellular environment holds a great deal of information, subsurface visualization remains a poorly explored area. Recently, it was discovered that by mechanically perturbing a sample, it was possible to observe its response in time with nanoscale resolution by probing the surface with a micro-resonator such as a microcantilever probe. Microcantilevers are used as the force-sensing probes in atomic force microscopy (AFM), where the nanometer-scale probe tip on the microcantilever interacts with the sample in a highly controlled manner to produce high-resolution raster-scanned information of the sample surface. Taking advantage of the existing capabilities of AFM, we present a novel technique, mode synthesizing atomic force microscopy (MSAFM), which has the ability to probe subsurface structures such as non-labeled nanoparticles embedded in a cell. In MSAFM mechanical actuators (PZTs) excite the probe and the sample at different frequencies as depicted in the first figure of this chapter. The nonlinear nature of the tip-sample interaction, at the point of contact of the probe and the surface of the sample, in the contact mode AFM configuration permits the mixing of the elastic waves. The new dynamic system comprises new

  5. Identification of phosphatidylserine as a ligand for the CD300a immunoreceptor

    SciTech Connect

    Nakahashi-Oda, Chigusa; Tahara-Hanaoka, Satoko; Honda, Shin-ichiro; Shibuya, Kazuko; Shibuya, Akira

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer CD300a is a new phosphatidylserine receptor expressed on myeloid cells. Black-Right-Pointing-Pointer Phosphatidylserine delivers a signal for recruitment of SHP-1 by CD300a in mast cells. Black-Right-Pointing-Pointer The CD300a/phosphatidylserine interaction is blocked by MFG-E8 or anti-CD300a antibody. -- Abstract: CD300a is a member of CD300 family molecules consisting of seven genes on human chromosome 17 and nine genes in mouse chromosome 11. CD300a has a long cytoplasmic region containing the consensus immunoreceptor tyrosine-based inhibitory motif (ITIM) sequence. Upon crosslinking with antibodies against CD300a, CD300a mediates an inhibitory signal in myeloid cells. However, the ligand for CD300a has not been identified and the physiological role of CD300a remained unclear. Here, we demonstrate that the chimeric fusion protein of CD300a extracellular domain with the Fc portion of human IgG specifically bound phosphatidylserine (PS), which is exposed on the outer leaflet of the plasma membrane of apoptotic cells. PS binding to CD300a induced SHP-1 recruitment by CD300a in mast cells in response to LPS. These results indicated that CD300a is a new PS receptor.

  6. Connecting Surface Planting with Subsurface Erosion Due to Groundwater Flow

    NASA Astrophysics Data System (ADS)

    Reardon, M.; Curran, J. C.

    2014-12-01

    Bank erosion and failure is a major contributor of fine sediment to streams and rivers, and can be driven by subsurface flow. In restoration projects, vegetation is often planted on banks to reduce erosion and stabilize the banks. However, the relationship between subsurface flow, erosion and vegetation remains somewhat speculative. A comparative study quantified the effect of surface planting on subsurface erosion and soil strength. Six 32-gallon containers were layered with a sandy loam overlying a highly conductive sand layer and a confining clay. Three treatments were applied in pairs: switchgrass (Panicum virgatum L.), sod (turf-type tall fescue and Kentucky bluegrass mix), and no vegetation. After a vegetation establishment period, the 2, 10, and 100 year rainfalls were simulated. Samples collected from ports in the containers were analyzed for subsurface drainage volume and suspended sediment concentration. After all rainfall simulations, a sediment core was taken from each container to measure shear strength and root density. Results indicate the relative benefits of vegetative planting to reduce subsurface erosion during storms and enhance soil strength. Switchgrass reduced the total amount of sediment removed from containers during all three storms when compared to the sod and during the 10 and 100 year storms when compared to the bare ground. Results from the volume analysis were more variable. Switchgrass retained the greatest volume of water from the 100 year storm event, but also released the largest fraction of water in the 2 and 10 year storms. Both sod and switchgrass planting considerably increased the time required for the soil samples to fail despite reducing the shear stress at failure. Where switchgrass grew long, woody roots, the sod developed a dense mat of interconnected thin roots. We suspect the different root patterns between sod and switchgrass to be a dominant factor in the response of the different containers.

  7. Metalliferous Biosignatures for Deep Subsurface Microbial Activity

    NASA Astrophysics Data System (ADS)

    Parnell, John; Brolly, Connor; Spinks, Sam; Bowden, Stephen

    2016-03-01

    The interaction of microbes and metals is widely assumed to have occurred in surface or very shallow subsurface environments. However new evidence suggests that much microbial activity occurs in the deep subsurface. Fluvial, lacustrine and aeolian `red beds' contain widespread centimetre-scale reduction spheroids in which a pale reduced spheroid in otherwise red rocks contains a metalliferous core. Most of the reduction of Fe (III) in sediments is caused by Fe (III) reducing bacteria. They have the potential to reduce a range of metals and metalloids, including V, Cu, Mo, U and Se, by substituting them for Fe (III) as electron acceptors, which are all elements common in reduction spheroids. The spheroidal morphology indicates that they were formed at depth, after compaction, which is consistent with a microbial formation. Given that the consequences of Fe (III) reduction have a visual expression, they are potential biosignatures during exploration of the terrestrial and extraterrestrial geological record. There is debate about the energy available from Fe (III) reduction on Mars, but the abundance of iron in Martian soils makes it one of the most valuable prospects for life there. Entrapment of the microbes themselves as fossils is possible, but a more realistic target during the exploration of Mars would be the colour contrasts reflecting selective reduction or oxidation. This can be achieved by analysing quartz grains across a reduction spheroid using Raman spectroscopy, which demonstrates its suitability for life detection in subsurface environments. Microbial action is the most suitable explanation for the formation of reduction spheroids and may act as metalliferous biosignatures for deep subsurface microbial activity.

  8. Subsurface fracture spacing

    SciTech Connect

    Lorenz, J.C. ); Hill, R.E. )

    1991-01-01

    This study was undertaken in order to document and analyze the unique set of data on subsurface fracture characteristics, especially spacing, provided by the US Department of Energy's Slant Hole Completion Test well (SHCT-1) in the Piceance Basin, Colorado. Two hundred thirty-six (236) ft (71.9 m) of slant core and 115 ft (35.1 m) of horizontal core show irregular, but remarkably close, spacings for 72 natural fractures cored in sandstone reservoirs of the Mesaverde Group. Over 4200 ft (1280 m) of vertical core (containing 275 fractures) from the vertical Multiwell Experiment wells at the same location provide valuable information on fracture orientation, termination, and height, but only data from the SHCT-1 core allow calculations of relative fracture spacing. Within the 162-ft (49-m) thick zone of overlapping core from the vertical and deviated wellbores, only one fracture is present in vertical core whereas 52 fractures occur in the equivalent SHCT-1 core. The irregular distribution of regional-type fractures in these heterogeneous reservoirs suggests that measurements of average fracture spacing'' are of questionable value as direct input parameters into reservoir engineering models. Rather, deviated core provides data on the relative degree of fracturing, and confirms that cross fractures can be rare in the subsurface. 13 refs., 11 figs.

  9. Subsurface Biogeochemistry of Actinides

    SciTech Connect

    Kersting, Annie B.; Zavarin, Mavrik

    2016-06-29

    A major scientific challenge in environmental sciences is to identify the dominant processes controlling actinide transport in the environment. It is estimated that currently, over 2200 metric tons of plutonium (Pu) have been deposited in the subsurface worldwide, a number that increases yearly with additional spent nuclear fuel (Ewing et al., 2010). Plutonium has been shown to migrate on the scale of kilometers, giving way to a critical concern that the fundamental biogeochemical processes that control its behavior in the subsurface are not well understood (Kersting et al., 1999; Novikov et al., 2006; Santschi et al., 2002). Neptunium (Np) is less prevalent in the environment; however, it is predicted to be a significant long-term dose contributor in high-level nuclear waste. Our focus on Np chemistry in this Science Plan is intended to help formulate a better understanding of Pu redox transformations in the environment and clarify the differences between the two long-lived actinides. The research approach of our Science Plan combines (1) Fundamental Mechanistic Studies that identify and quantify biogeochemical processes that control actinide behavior in solution and on solids, (2) Field Integration Studies that investigate the transport characteristics of Pu and test our conceptual understanding of actinide transport, and (3) Actinide Research Capabilities that allow us to achieve the objectives of this Scientific Focus Area (SFA and provide new opportunities for advancing actinide environmental chemistry. These three Research Thrusts form the basis of our SFA Science Program (Figure 1).

  10. Subsurface Tectonics and Pingos of Northern Alaska

    NASA Astrophysics Data System (ADS)

    Skirvin, S.; Casavant, R.; Burr, D.

    2008-12-01

    We describe preliminary results of a two-phase study that investigated links between subsurface structural and stratigraphic controls, and distribution of hydrostatic pingos on the central coastal plain of Arctic Alaska. Our 2300 km2 study area is underlain by a complete petroleum system that supports gas, oil and water production from 3 of the largest oil fields in North America. In addition, gas hydrate deposits exist in this area within and just below the permafrost interval at depths of 600 to 1800 feet below sea level. Phase 1 of the study compared locations of subsurface faults and pingos for evidence of linkages between faulting and pingo genesis and distribution. Several hundred discrete fault features were digitized from published data and georeferenced in a GIS database. Fault types were determined by geometry and sense of slip derived from well log and seismic maps. More than 200 pingos and surface sediment type associated with their locations were digitized from regional surficial geology maps within an area that included wire line and seismic data coverage. Beneath the pingos lies an assemblage of high-angle normal and transtensional faults that trend NNE and NW; subsidiary trends are EW and NNW. Quaternary fault reactivation is evidenced by faults that displaced strata at depths exceeding 3000 meters below sea level and intersect near-surface units. Unpublished seismic images and cross-section analysis support this interpretation. Kinematics and distribution of reactivated faults are linked to polyphase deformational history of the region that includes Mesozoic rift events, succeeded by crustal shortening and uplift of the Brooks Range to the south, and differential subsidence and segmentation of a related foreland basin margin beneath the study area. Upward fluid migration, a normal process in basin formation and fault reactivation, may play yet unrecognized roles in the genesis (e.g. fluid charging) of pingos and groundwater hydrology. Preliminary

  11. Microbial Community Composition in the Marine Sediments of Jeju Island: Next-Generation Sequencing Surveys.

    PubMed

    Choi, Heebok; Koh, Hyeon-Woo; Kim, Hongik; Chae, Jong-Chan; Park, Soo-Je

    2016-05-28

    Marine sediments are a microbial biosphere with an unknown physiology, and the sediments harbor numerous distinct phylogenetic lineages of Bacteria and Archaea that are at present uncultured. In this study, the structure of the archaeal and bacterial communities was investigated in the surface and subsurface sediments of Jeju Island using a next-generation sequencing method. The microbial communities in the surface sediments were distinct from those in the subsurface sediments; the relative abundance of sequences for Thaumarchaeota, Actinobacteria, Bacteroides, Alphaproteobacteria, and Gammaproteobacteria were higher in the surface than subsurface sediments, whereas the sequences for Euryarchaeota, Acidobacteria, Firmicutes, and Deltaproteobacteria were relatively more abundant in the subsurface than surface sediments. This study presents detailed characterization of the spatial distribution of benthic microbial communities of Jeju Island and provides fundamental information on the potential interactions mediated by microorganisms with the different biogeochemical cycles in coastal sediments.

  12. Comparison and assessment of four sediment particle-size analysis methodologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment particle-size analysis is a fundamental component of a wide variety of environmental disciplines such as sediment transport dynamics, subsurface and groundwater flow, lacustrine depositional history, and nutrient transport. There are several readily available methods for measuring particle ...

  13. 76 FR 23218 - Airworthiness Directives; Airbus Model A330-200, A330-300, A340-300, A340-500, and A340-600...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ...-200, A330-300, A340- 300, A340-500, and A340-600 Series Airplanes AGENCY: Federal Aviation... inoperative (from GO IF to NO GO) as an interim solution, limited to A330 and A340-300 fitted with electrical... retaining its requirements, requires the installation of: --a new BCM on A330 and A340-300 series...

  14. 17 CFR 301.300a - Form 300-A, for summary of buy-ins or sell-outs of all open contractual commitments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 300-A, for summary of buy... Form 300-A, for summary of buy-ins or sell-outs of all open contractual commitments. This form shall be... summarize the buy-ins and sell-outs of those open contractual commitments and shall be accompanied by...

  15. Nonintrusive subsurface surveying capability

    SciTech Connect

    Tunnell, T.W.; Cave, S.P.

    1994-06-01

    This presentation describes the capabilities of a ground-pentrating radar (GPR) system developed by EG&G Energy Measurements (EM), a prime contractor to the Department of Energy (DOE). The focus of the presentation will be on the subsurface survey of DOE site TA-21 in Los Alamos, New Mexico. EG&G EM developed the system for the Department of Defense. The system is owned by the Department of the Army and currently resides at KO in Albuquerque. EM is pursuing efforts to transfer this technology to environmental applications such as waste-site characterization with DOE encouragement. The Army has already granted permission to use the system for the waste-site characterization activities.

  16. Containment of subsurface contaminants

    DOEpatents

    Corey, J.C.

    1994-09-06

    A barrier is disclosed for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates. 5 figs.

  17. Containment of subsurface contaminants

    DOEpatents

    Corey, John C.

    1994-01-01

    A barrier for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates.

  18. Subsurface Samples: Collection and Processing

    SciTech Connect

    Long, Philip E.; Griffin, W. Timothy; Phelps, Tommy J.

    2002-12-01

    Microbiological data, interpretation, and conclusions from subsurface samples ultimately depend on the quality and representative character of the samples. Subsurface samples for environmental microbiology ideally contain only the microbial community and geochemical properties that are representative of the subsurface environment from which the sample was taken. To that end, sample contamination by exogenous microorganisms or chemical constituents must be eliminated or minimized, and sample analyses need to begin before changes in the microbial community or geochemical characteristics occur. This article presents sampling methods and sample processing techniques for collecting representative samples from a range of subsurface environments. Factors that should be considered when developing a subsurface sampling program are discussed, including potential benefits, costs, and limitations enabling researchers to evaluate the techniques that are presented and match them to their project requirements. Methods and protocols to address coring, sampling, processing and quality assessment issues are presented.

  19. Uranium Biomineralization by Natural Microbial Phosphatase Activities in the Subsurface

    SciTech Connect

    Sobecky, Patricia A.

    2015-04-06

    In this project, inter-disciplinary research activities were conducted in collaboration among investigators at The University of Alabama (UA), Georgia Institute of Technology (GT), Lawrence Berkeley National Laboratory (LBNL), Brookhaven National Laboratory (BNL), the DOE Joint Genome Institute (JGI), and the Stanford Synchrotron Radiation Light source (SSRL) to: (i) confirm that phosphatase activities of subsurface bacteria in Area 2 and 3 from the Oak Ridge Field Research Center result in solid U-phosphate precipitation in aerobic and anaerobic conditions; (ii) investigate the eventual competition between uranium biomineralization via U-phosphate precipitation and uranium bioreduction; (iii) determine subsurface microbial community structure changes of Area 2 soils following organophosphate amendments; (iv) obtain the complete genome sequences of the Rahnella sp. Y9-602 and the type-strain Rahnella aquatilis ATCC 33071 isolated from these soils; (v) determine if polyphosphate accumulation and phytate hydrolysis can be used to promote U(VI) biomineralization in subsurface sediments; (vi) characterize the effect of uranium on phytate hydrolysis by a new microorganism isolated from uranium-contaminated sediments; (vii) utilize positron-emission tomography to label and track metabolically-active bacteria in soil columns, and (viii) study the stability of the uranium phosphate mineral product. Microarray analyses and mineral precipitation characterizations were conducted in collaboration with DOE SBR-funded investigators at LBNL. Thus, microbial phosphorus metabolism has been shown to have a contributing role to uranium immobilization in the subsurface.

  20. Taxonomic study of aromatic-degrading bacteria from deep-terrestrial-subsurface sediments and description of Sphingomonas aromaticivorans sp. nov., Sphingomonas subterranea sp. nov., and Sphingomonas stygia sp. nov.

    PubMed

    Balkwill, D L; Drake, G R; Reeves, R H; Fredrickson, J K; White, D C; Ringelberg, D B; Chandler, D P; Romine, M F; Kennedy, D W; Spadoni, C M

    1997-01-01

    Phylogenetic analyses of 16S rRNA gene sequences by distance matrix and parsimony methods indicated that six strains of bacteria isolated from deep saturated Atlantic coastal plain sediments were closely related to the genus Sphingomonas. Five of the strains clustered with, but were distinct from, Sphingomonas capsulata, whereas the sixth strain was most closely related to Blastobacter natatorius. The five strains that clustered with S. capsulata, all of which could degrade aromatic compounds, were gram-negative, non-spore-forming, non-motile, rod-shaped organisms that produced small, yellow colonies on complex media. Their G + C contents ranged from 60.0 to 65.4 mol%, and the predominant isoprenoid quinone was ubiquinone Q-10. All of the strains were aerobic and catalase positive. Indole, urease, and arginine dihydrolase were not produced. Gelatin was not liquified, and glucose was not fermented. Sphingolipids were present in all strains; 2OH14:0 was the major hydroxy fatty acid, and 18:1 was a major constituent of cellular lipids. Acid was produced oxidatively from pentoses, hexoses, and disaccharides, but not from polyalcohols and indole. All of these characteristics indicate that the five aromatic-degrading strains should be placed in the genus Sphingomonas as currently defined. Phylogenetic analysis of 16S rRNA gene sequences, DNA-DNA reassociation values, BOX-PCR genomic fingerprinting, differences in cellular lipid composition, and differences in physiological traits all indicated that the five strains represent three previously undescribed Sphingomonas species. Therefore, we propose the following new species: Sphingomonas aromaticivorans (type strain, SMCC F199), Sphingomonas subterranea (type strain, SMCC B0478), and Sphingomonas stygia (type strain, SMCC B0712).

  1. Ecology, physiology, and phylogeny of deep subsurface Sphingomonas sp.

    SciTech Connect

    Fredrickson, Jim K.; Balkwill, David L.; Romine, Margaret F.; Shi, T

    1999-10-01

    Several new species of the genus Sphingomonas including S. aromaticivorans, S. stygia, and S. subterranea that have the capacity for degrading a broad range of aromatic compounds including toluene, naphthalene, xylenes, p-cresol, fluorene, biphenyl, and dibenzothiophene, were isolated from deeply-buried (>200 m) sediments of the US Atlantic coastal plain (ACP). In S. aromaticivorans F199, many of the genes involved in the catabolism of these aromatic compounds are encoded on a 184-kb conjugative plasmid; some of the genes involved in aromatic catabolism are plasmid-encoded in the other strains as well. Members of the genus Sphingomonas were common among aerobic heterotrophic bacteria cultured from ACP sediments and have been detected in deep subsurface environments elsewhere. The major source of organic carbon for heterotrophic metabolism in ACP deep aquifers is lignite that originated from plant material buried with the sediments. We speculate that the ability of the subsurface Sphingomonas strains to degrade a wide array of aromatic compounds represents an adaptation for utilization of sedimentary lignite. These and related subsurface Sphingomonas spp may play an important role in the transformation of sedimentary organic carbon in the aerobic and microaerobic regions of the deep aquifers of the ACP.

  2. From surface to subsurface and back again: the contribution of subsurface particle motion to surface armoring

    NASA Astrophysics Data System (ADS)

    Ferdowsi, B.; Jerolmack, D. J.; Ortiz, C. P.; Houssais, M.

    2015-12-01

    Armoring is the development of a coarse surface layer of sediments on a river bed, which overlies a smaller and typically more heterogeneous substrate. All existing models for this phenomenon are predicated on the idea that armoring develops due to size-selective transport and kinetic sieving at the surface of the granular bed. Here examine the development of armoring in the absence of size-selective surface transport, and demonstrate that subsurface particle movement can create an armored surface layer. We first conduct experiments in a laminar and annular flume, over a range of Shields stresses, with bimodal and refractive index-matched spherical sediments; this allows us to image the internal motion of the granular bed that is sheared from above by a viscous oil. Fluid-driven particle motion of the surface layer results in granular shear, that drives motion deep into the bed. This subsurface motion causes an upward migration of coarser particles, at a rate that is proportional to the granular shear rate. Comparison of experimental results to an existing continuum-granular flow model suggest that armoring in our bed-load exeriments is entirely consistent with shear-induced segregation in dry avalanches - but is slower. There is no size-selective transport at the surface in the experiments, as the annular flume is mass conserving and all particles move as bed load; this was confirmed by observation. To probe the granular physics of armor development further, we perform numerical simulations using a discrete element model (DEM) of granular flow, with and without damping. Simulations reproduce salient features of the experiments, and indicate that armoring is robust but that the rate of segregation is related to the degree of viscous damping. We posit that subsurface granular flow is an important and perhaps dominant contributor to surface armoring in rivers. More generally, this work shows how information is transferred from the surface to the subsurface and back

  3. 76 FR 52217 - Airworthiness Directives; Airbus Model A330-200, A330-300, A340-300, A340-500, and A340-600...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-22

    ...-200, A330-300, A340- 300, A340-500, and A340-600 Series Airplanes AGENCY: Federal Aviation... dispatch with FCPC3 inoperative (from GO IF to NO GO) as an interim solution, limited to A330 and A340-300... and A340-200/-300 series aeroplanes fitted with electrical rudder, and --an improved PFTU on A330...

  4. Microbial Transport in the Subsurface

    SciTech Connect

    Ginn, Timothy R.; Camesano, Terri; Scheibe, Timothy D.; Nelson, Kirk B.; Clement, T. P.; Wood, Brian D.

    2005-12-01

    In this article we focus on the physical, chemical, and biological processes involved in the transport of bacteria in the saturated subsurface. We will first review conceptual models of bacterial phases in the subsurface, and then the processes controlling fate and transport on short (e.g., bioremediation) time scales. Finally we briefly review field bacterial transport experiments and discuss a number of issues that impact the application of current process descriptions and models at the field scale.

  5. Detection of microbial Life in the Subsurface

    NASA Astrophysics Data System (ADS)

    Stan-Lotter, H.; Fendrihan, S.; Dornmayr-Pfaffenhuemer, M.; Legat, A.; Gruber, C.; Weidler, G.; Gerbl, F.

    2007-08-01

    In recent years microbial communities were detected, which dwell in rocks, soil and caves deep below the surface of the Earth. This has led to a new view of the diversity of the terrestrial biosphere and of the physico-chemical boundaries for life. Two types of subterranean environments are Permo-Triassic salt sediments and thermal radioactive springs from igneous rocks in the Alps. Viable extremely halophilic archaea were isolated from ancient salt sediments which are estimated to be about 250 million years old (1). Chemotaxonomic and molecular characterization showed that they represent novel species, e. g. Halococcus salifodinae, Hcc. dombrowskiiand Halobacterium noricense. Simulation experiments with artificial halite suggested that these microorganisms probably survived while embedded in fluid inclusions. In the thermal springs, evidence for numerous novel microorganisms was found by 16S rDNA sequencing and probing for some metabolic genes; in addition, scanning electron microscopy of biofilms on the rock surfaces revealed great diversity of morphotypes (2). These communities appear to be active and growing, although their energy and carbon sources are entirely unknown. The characterization of subsurface inhabitants is of astrobiological relevance since extraterrestrial halite has been detected (3) and since microbial life on Mars, if existent, may have retreated into the subsurface. As a long-term goal, a thorough census of terrestrial microorganisms should be taken and their survival potential be determined in view of future missions for the search for extraterrestrial life, including planning precautions against possible forward contamination by space probes. (1) Fendrihan, S., Legat, A., Gruber, C., Pfaffenhuemer, M., Weidler, G., Gerbl, F., Stan-Lotter, H. (2006) Extremely halophilic archaea and the issue of long term microbial survival. Reviews in Environmental Science and Bio/technology 5, 1569-1605. (2) Weidler, G.W., Dornmayr-Pfaffenhuemer, M., Gerbl

  6. Subsurface Geotechnical Parameters Report

    SciTech Connect

    D. Rigby; M. Mrugala; G. Shideler; T. Davidsavor; J. Leem; D. Buesch; Y. Sun; D. Potyondy; M. Christianson

    2003-12-17

    The Yucca Mountain Project is entering a the license application (LA) stage in its mission to develop the nation's first underground nuclear waste repository. After a number of years of gathering data related to site characterization, including activities ranging from laboratory and site investigations, to numerical modeling of processes associated with conditions to be encountered in the future repository, the Project is realigning its activities towards the License Application preparation. At the current stage, the major efforts are directed at translating the results of scientific investigations into sets of data needed to support the design, and to fulfill the licensing requirements and the repository design activities. This document addresses the program need to address specific technical questions so that an assessment can be made about the suitability and adequacy of data to license and construct a repository at the Yucca Mountain Site. In July 2002, the U.S. Nuclear Regulatory Commission (NRC) published an Integrated Issue Resolution Status Report (NRC 2002). Included in this report were the Repository Design and Thermal-Mechanical Effects (RDTME) Key Technical Issues (KTI). Geotechnical agreements were formulated to resolve a number of KTI subissues, in particular, RDTME KTIs 3.04, 3.05, 3.07, and 3.19 relate to the physical, thermal and mechanical properties of the host rock (NRC 2002, pp. 2.1.1-28, 2.1.7-10 to 2.1.7-21, A-17, A-18, and A-20). The purpose of the Subsurface Geotechnical Parameters Report is to present an accounting of current geotechnical information that will help resolve KTI subissues and some other project needs. The report analyzes and summarizes available qualified geotechnical data. It evaluates the sufficiency and quality of existing data to support engineering design and performance assessment. In addition, the corroborative data obtained from tests performed by a number of research organizations is presented to reinforce

  7. Actinobacterial diversity across a marine transgression in the deep subsurface off Shimokita Peninsula, Japan

    NASA Astrophysics Data System (ADS)

    Harrison, B. K.; Bailey, J. V.

    2013-12-01

    Sediment horizons represent a significant - but not permanent - barrier to microbial transport. Cells commonly attach to mineral surfaces in unconsolidated sediments. However, by taxis, growth, or passive migration under advecting fluids, some portion of the microbial community may transgress sedimentary boundaries. Few studies have attempted to constrain such transport of community signatures in the marine subsurface and its potential impact on biogeography. Integrated Ocean Drilling Program (IODP) Expedition 337 off the Shimokita Peninsula recovered sediments over a greater than 1km interval representing a gradual decrease of terrestrial influence, from tidal to continental shelf depositional settings. This sequence represents a key opportunity to link subsurface microbial communities to lithological variability and investigate the permanence of community signatures characteristic of distinct depositional regimes. The phylogenetic connectivity between marine and terrestrially-influenced deposits may demonstrate to what degree sediments offer a substantial barrier to cell transport in the subsurface. Previous work has demonstrated that the Actinobacterial phylum is broadly distributed in marine sediments (Maldonado et al., 2005), present and active in the deep subsurface (Orsi et al., 2013), and that marine and terrestrial lineages may potentially be distinguished by 16S rRNA gene sequencing (e.g. Prieto-Davó et al., 2013). We report on Actinobacteria-specific 16S rRNA gene diversity recovered between 1370 and 2642 mbsf with high-throughput sequencing using the Illumina MiSeq platform, as well as selective assembly and analysis of environmental clone libraries.

  8. Microbial communities in the deep subsurface

    NASA Astrophysics Data System (ADS)

    Krumholz, Lee R.

    The diversity of microbial populations and microbial communities within the earth's subsurface is summarized in this review. Scientists are currently exploring the subsurface and addressing questions of microbial diversity, the interactions among microorganisms, and mechanisms for maintenance of subsurface microbial communities. Heterotrophic anaerobic microbial communities exist in relatively permeable sandstone or sandy sediments, located adjacent to organic-rich deposits. These microorganisms appear to be maintained by the consumption of organic compounds derived from adjacent deposits. Sources of organic material serving as electron donors include lignite-rich Eocene sediments beneath the Texas coastal plain, organic-rich Cretaceous shales from the southwestern US, as well as Cretaceous clays containing organic materials and fermentative bacteria from the Atlantic Coastal Plain. Additionally, highly diverse microbial communities occur in regions where a source of organic matter is not apparent but where igneous rock is present. Examples include the basalt-rich subsurface of the Columbia River valley and the granitic subsurface regions of Sweden and Canada. These subsurface microbial communities appear to be maintained by the action of lithotrophic bacteria growing on H2 that is chemically generated within the subsurface. Other deep-dwelling microbial communities exist within the deep sediments of oceans. These systems often rely on anaerobic metabolism and sulfate reduction. Microbial colonization extends to the depths below which high temperatures limit the ability of microbes to survive. Energy sources for the organisms living in the oceanic subsurface may originate as oceanic sedimentary deposits. In this review, each of these microbial communities is discussed in detail with specific reference to their energy sources, their observed growth patterns, and their diverse composition. This information is critical to develop further understanding of subsurface

  9. Genomic inference of the metabolism of cosmopolitan subsurface Archaea, Hadesarchaea.

    PubMed

    Baker, Brett J; Saw, Jimmy H; Lind, Anders E; Lazar, Cassandre Sara; Hinrichs, Kai-Uwe; Teske, Andreas P; Ettema, Thijs J G

    2016-02-15

    The subsurface biosphere is largely unexplored and contains a broad diversity of uncultured microbes(1). Despite being one of the few prokaryotic lineages that is cosmopolitan in both the terrestrial and marine subsurface(2-4), the physiological and ecological roles of SAGMEG (South-African Gold Mine Miscellaneous Euryarchaeal Group) Archaea are unknown. Here, we report the metabolic capabilities of this enigmatic group as inferred from genomic reconstructions. Four high-quality (63-90% complete) genomes were obtained from White Oak River estuary and Yellowstone National Park hot spring sediment metagenomes. Phylogenomic analyses place SAGMEG Archaea as a deeply rooting sister clade of the Thermococci, leading us to propose the name Hadesarchaea for this new Archaeal class. With an estimated genome size of around 1.5 Mbp, the genomes of Hadesarchaea are distinctly streamlined, yet metabolically versatile. They share several physiological mechanisms with strict anaerobic Euryarchaeota. Several metabolic characteristics make them successful in the subsurface, including genes involved in CO and H2 oxidation (or H2 production), with potential coupling to nitrite reduction to ammonia (DNRA). This first glimpse into the metabolic capabilities of these cosmopolitan Archaea suggests they are mediating key geochemical processes and are specialized for survival in the subsurface biosphere.

  10. Martian sub-surface ionising radiation: biosignatures and geology

    NASA Astrophysics Data System (ADS)

    Dartnell, L. R.; Desorgher, L.; Ward, J. M.; Coates, A. J.

    2007-02-01

    The surface of Mars, unshielded by thick atmosphere or global magnetic field, is exposed to high levels of cosmic radiation. This ionizing radiation field is deleterious to the survival of dormant cells or spores and the persistence of molecular biomarkers in the subsurface, and so its characterisation is of prime astrobiological interest. Previous research has attempted to address the question of biomarker persistence by inappropriately using dose profiles weighted specifically for cellular survival. Here, we present modelling results of the unmodified physically absorbed radiation dose as a function of depth through the Martian subsurface. A second major implementation of this dose accumulation rate data is in application of the optically stimulated luminescence technique for dating Martian sediments. We present calculations of the dose-depth profile from galactic cosmic rays in the Martian subsurface for various scenarios: variations of surface composition (dry regolith, ice, layered permafrost), solar minimum and maximum conditions, locations of different elevation (Olympus Mons, Hellas basin, datum altitude), and increasing atmospheric thickness over geological history. We also model the changing composition of the subsurface radiation field with depth compared between Martian locations with different shielding material, determine the relative dose contributions from primaries of different energies, and briefly treat particle deflection by the crustal magnetic fields.

  11. Endoscopic subsurface imaging in tissues

    SciTech Connect

    Demos, S G; Staggs, M; Radousky, H B

    2001-02-12

    The objective of this work is to develop endoscopic subsurface optical imaging technology that will be able to image different tissue components located underneath the surface of the tissue at an imaging depth of up to 1 centimeter. This effort is based on the utilization of existing technology and components developed for medical endoscopes with the incorporation of the appropriate modifications to implement the spectral and polarization difference imaging technique. This subsurface imaging technique employs polarization and spectral light discrimination in combination with image processing to remove a large portion of the image information from the outer layers of the tissue which leads to enhancement of the contrast and image quality of subsurface tissue structures.

  12. Measuring isotropic subsurface light transport.

    PubMed

    Happel, Kathrin; Dörsam, Edgar; Urban, Philipp

    2014-04-21

    Subsurface light transport can affect the visual appearance of materials significantly. Measuring and modeling this phenomenon is crucial for accurately reproducing colors in printing or for rendering translucent objects on displays. In this paper, we propose an apparatus to measure subsurface light transport employing a reference material to cancel out adverse signals that may bias the results. In contrast to other approaches, the setup enables improved focusing on rough surfaces (e.g. uncoated paper). We derive a measurement equation that may be used to deduce the point spread function (PSF) of subsurface light transport. Main contributions are the usage of spectrally-narrowband exchangeable LEDs allowing spectrally-resolved measurements and an approach based on quadratic programming for reconstructing PSFs in the case of isotropic light transport.

  13. Subsurface microbial habitats on Mars

    NASA Technical Reports Server (NTRS)

    Boston, P. J.; Mckay, C. P.

    1991-01-01

    We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on geothermal hot spots existing below the near or deep subsurface of Mars. Recent advances in the comparatively new field of deep subsurface microbiology have revealed previously unsuspected rich aerobic and anaerobic microbal communities far below the surface of the Earth. Such habitats, protected from the grim surface conditions on Mars, could receive warmth from below and maintain water in its liquid state. In addition, geothermally or volcanically reduced gases percolating from below through a microbiologically active zone could provide the reducing power needed for a closed or semi-closed microbial ecosystem to thrive.

  14. Towed Subsurface Optical Communications Buoy

    NASA Technical Reports Server (NTRS)

    Stirbl, Robert C.; Farr, William H.

    2013-01-01

    The innovation allows critical, high-bandwidth submarine communications at speed and depth. This reported innovation is a subsurface optical communications buoy, with active neutral buoyancy and streamlined flow surface veins for depth control. This novel subsurface positioning for the towed communications buoy enables substantial reduction in water-absorption and increased optical transmission by eliminating the intervening water absorption and dispersion, as well as by reducing or eliminating the beam spread and the pulse spreading that is associated with submarine-launched optical beams.

  15. Coastal sedimentation

    NASA Technical Reports Server (NTRS)

    Schubel, J. R.

    1980-01-01

    Several important coastal sedimentation problems are identified. Application of existing or anticipated remote sensing techniques to examine these problems is considered. Specifically, coastal fine particle sediment systems, floods and hy hurricanes and sedimentation f of coastal systems, routes and rates of sediment transport on continental shelves, and dredging and dredged material disposal are discussed.

  16. Microbial production and oxidation of methane in deep subsurface

    NASA Astrophysics Data System (ADS)

    Kotelnikova, Svetlana

    2002-10-01

    The goal of this review is to summarize present studies on microbial production and oxidation of methane in the deep subterranean environments. Methane is a long-living gas causing the "greenhouse" effect in the planet's atmosphere. Earlier, the deep "organic carbon poor" subsurface was not considered as a source of "biogenic" methane. Evidence of active methanogenesis and presence of viable methanogens including autotrophic organisms were obtained for some subsurface environments including water-flooded oil-fields, deep sandy aquifers, deep sea hydrothermal vents, the deep sediments and granitic groundwater at depths of 10 to 2000 m below sea level. As a rule, the deep subterranean microbial populations dwell at more or less oligotrophic conditions. Molecular hydrogen has been found in a variety of subsurface environments, where its concentrations were significantly higher than in the tested surface aquatic environments. Chemolithoautotrophic microorganisms from deep aquifers that could grow on hydrogen and carbon dioxide can act as primary producers of organic carbon, initiating heterotrophic food chains in the deep subterranean environments independent of photosynthesis. "Biogenic" methane has been found all over the world. On the basis of documented occurrences, gases in reservoirs and older sediments are similar and have the isotopic character of methane derived from CO 2 reduction. Groundwater representing the methanogenic end member are characterized by a relative depletion of dissolved organic carbon (DOC) in combination with an enrichment in 13C in inorganic carbon, which is consistent with the preferential reduction of 12CO 2 by autotrophic methanogens or acetogens. The isotopic composition of methane formed via CO 2 reduction is controlled by the δ13C of the original CO 2 substrate. Literature data shows that CH 4 as heavy as -40‰ or -50‰ can be produced by the microbial reduction of isotopically heavy CO 2. Produced methane may be oxidized

  17. ASSESSMENT OF THE SUBSURFACE FATE OF MONOETHANOLAMINE

    SciTech Connect

    James A. Sorensen; John R. Gallagher; Lori G. Kays

    2000-05-01

    Burial of amine reclaimer unit sludges and system filters has resulted in contamination of soil at the CanOxy Okotoks decommissioned sour gas-processing plant with amines, amine byproducts, and salts. A three-phase research program was devised to investigate the natural attenuation process that controls the subsurface transport and fate of these contaminants and to apply the results toward the development of a strategy for the remediation of this type of contamination in soils. Phase I experimental activities examined interactions between monoethanolamine (MEA) and sediment, the biodegradability of MEA in soils at various concentrations and temperatures, and the biodegradability of MEA sludge contamination in a soil slurry bioreactor. The transport and fate of MEA in the subsurface was found to be highly dependant on the nature of the release, particularly MEA concentration and conditions of the subsurface environment, i.e., pH, temperature, and oxygen availability. Pure compound biodegradation experiments in soil demonstrated rapid biodegradation of MEA under aerobic conditions and moderate temperatures (>6 C). Phase II landfarming activities confirmed that these contaminants are readily biodegradable in soil under ideal laboratory conditions, yet considerable toxicity was observed in the remaining material. Examination of water extracts from the treated soil suggested that the toxicity is water-soluble. Phase II activities led to the conclusion that landfarming is not the most desirable bioremediation technique; however, an engineered biopile with a leachate collection system could remove the remaining toxic fraction from the soil. Phase III was initiated to conduct field-based experimental activities to examine the optimized remediation technology. A pilot-scale engineered biopile was constructed at a decommissioned gas-sweetening facility in Okotoks, Alberta, Canada. On the basis of a review of the analytical and performance data generated from soil and

  18. SUBSURFACE VISUAL ALARM SYSTEM ANALYSIS

    SciTech Connect

    D.W. Markman

    2001-08-06

    The ''Subsurface Fire Hazard Analysis'' (CRWMS M&O 1998, page 61), and the document, ''Title III Evaluation Report for the Surface and Subsurface Communication System'', (CRWMS M&O 1999a, pages 21 and 23), both indicate the installed communication system is adequate to support Exploratory Studies Facility (ESF) activities with the exception of the mine phone system for emergency notification purposes. They recommend the installation of a visual alarm system to supplement the page/party phone system The purpose of this analysis is to identify data communication highway design approaches, and provide justification for the selected or recommended alternatives for the data communication of the subsurface visual alarm system. This analysis is being prepared to document a basis for the design selection of the data communication method. This analysis will briefly describe existing data or voice communication or monitoring systems within the ESF, and look at how these may be revised or adapted to support the needed data highway of the subsurface visual alarm. system. The existing PLC communication system installed in subsurface is providing data communication for alcove No.5 ventilation fans, south portal ventilation fans, bulkhead doors and generator monitoring system. It is given that the data communication of the subsurface visual alarm system will be a digital based system. It is also given that it is most feasible to take advantage of existing systems and equipment and not consider an entirely new data communication system design and installation. The scope and primary objectives of this analysis are to: (1) Briefly review and describe existing available data communication highways or systems within the ESF. (2) Examine technical characteristics of an existing system to disqualify a design alternative is paramount in minimizing the number of and depth of a system review. (3) Apply general engineering design practices or criteria such as relative cost, and degree of

  19. Tillage impact on herbicide loss by surface runoff and lateral subsurface flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is worldwide interest in conservation tillage practices because they can reduce surface runoff, agrichemical, and sediment loss from farm fields. Since these practices typically increase infiltration, their use may increase subsurface transport of water-soluble contaminants. Thus, to assess lo...

  20. Tillage impact on herbicide loss by surface runoff and lateral subsurface flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is worldwide interest in conservation tillage practices because they can reduce surface runoff, and agrichemical and sediment losses from farm fields. Since these practices typically increase infiltration, their use may increase subsurface transport of water-soluble contaminants. Thus, to asse...

  1. Deep Subsurface Life from North Pond: Enrichment, Isolation, Characterization and Genomes of Heterotrophic Bacteria

    PubMed Central

    Russell, Joseph A.; León-Zayas, Rosa; Wrighton, Kelly; Biddle, Jennifer F.

    2016-01-01

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic water-column west of the Mid-Atlantic Ridge at 22°N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. The cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface. PMID:27242705

  2. Subsurface Electromagnetic Target Characterization and Identification

    DTIC Science & Technology

    1979-06-01

    B. Subsurface Electromagnetic Video Pulse Radar System 5 C. The Subsurface Targets 11 D. Raw Measured Waveforms 14 E. Processed Waveforms 15 III...259 r i. I .. . . .... .. . . . . .;. . . . .. .. o _ • v . . • • • -• -. . .. -"... .. . II II LIST OF FIGURES Figure Page 1 The subsurface pulse ...7 3 Typical raw waveform received by the pulse radar system ..... ................... .i..... 9 4 Physical characteristics of the subsurface

  3. The genome of Geobacter bemidjiensis, exemplar for the subsurface clade of Geobacter species that predominate in Fe(III)-reducing subsurface environments

    SciTech Connect

    Aklujkar, Muktak; Young, Nelson D; Holmes, Dawn; Chavan, Milind; Risso, Carla; Kiss, Hajnalka; Han, Cliff; Land, Miriam L; Lovley, Derek

    2010-01-01

    Background. Geobacter species in a phylogenetic cluster known as subsurface clade 1 are often the predominant microorganisms in subsurface environments in which Fe(III) reduction is the primary electron-accepting process. Geobacter bemidjiensis, a member of this clade, was isolated from hydrocarbon-contaminated subsurface sediments in Bemidji, Minnesota, and is closely related to Geobacter species found to be abundant at other subsurface sites. This study examines whether there are significant differences in the metabolism and physiology of G. bemidjiensis compared to non-subsurface Geobacter species. Results. Annotation of the genome sequence of G. bemidjiensis indicates several differences in metabolism compared to previously sequenced non-subsurface Geobacteraceae, which will be useful for in silico metabolic modeling of subsurface bioremediation processes involving Geobacter species. Pathways can now be predicted for the use of various carbon sources such as propionate by G. bemidjiensis. Additional metabolic capabilities such as carbon dioxide fixation and growth on glucose were predicted from the genome annotation. The presence of different dicarboxylic acid transporters and two oxaloacetate decarboxylases in G. bemidjiensis may explain its ability to grow by disproportionation of fumarate. Although benzoate is the only aromatic compound that G. bemidjiensis is known or predicted to utilize as an electron donor and carbon source, the genome suggests that this species may be able to detoxify other aromatic pollutants without degrading them. Furthermore, G. bemidjiensis is auxotrophic for 4-aminobenzoate, which makes it the first Geobacter species identified as having a vitamin requirement. Several features of the genome indicated that G. bemidjiensis has enhanced abilities to respire, detoxify and avoid oxygen. Conclusion. Overall, the genome sequence of G. bemidjiensis offers surprising insights into the metabolism and physiology of Geobacteraceae in

  4. Targeting sediment management strategies using sediment quantification and fingerprinting methods

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie; Rowan, John; Fenton, Owen; Jordan, Phil; hUallacháin, Daire Ó.

    2016-04-01

    Cost-effective sediment management is required to reduce excessive delivery of fine sediment due to intensive land uses such as agriculture, resulting in the degradation of aquatic ecosystems. Prioritising measures to mitigate dominant sediment sources is, however, challenging, as sediment loss risk is spatially and temporally variable between and within catchments. Fluctuations in sediment supply from potential sources result from variations in land uses resulting in increased erodibility where ground cover is low (e.g., cultivated, poached and compacted soils), and physical catchment characteristics controlling hydrological connectivity and transport pathways (surface and/or sub-surface). Sediment fingerprinting is an evidence-based management tool to identify sources of in-stream sediments at the catchment scale. Potential sediment sources are related to a river sediment sample, comprising a mixture of source sediments, using natural physico-chemical characteristics (or 'tracers'), and contributions are statistically un-mixed. Suspended sediment data were collected over two years at the outlet of three intensive agricultural catchments (approximately 10 km2) in Ireland. Dominant catchment characteristics were grassland on poorly-drained soils, arable on well-drained soils and arable on moderately-drained soils. High-resolution (10-min) calibrated turbidity-based suspended sediment and discharge data were combined to quantify yield. In-stream sediment samples (for fingerprinting analysis) were collected at six to twelve week intervals, using time-integrated sediment samplers. Potential sources, including stream channel banks, ditches, arable and grassland field topsoils, damaged road verges and tracks were sampled, oven-dried (<40oC) and sieved (125 microns). Soil and sediment samples were analysed for mineral magnetics, geochemistry and radionuclide tracers, particle size distribution and soil organic carbon. Tracer data were corrected to account for particle

  5. RADIOIODINE GEOCHEMISTRY IN THE SRS SUBSURFACE ENVIRONMENT

    SciTech Connect

    Kaplan, D.; Emerson, H.; Powell, B.; Roberts, K.; Zhang, S.; Xu, C.; Schwer, K.; Li, H.; Ho, Y.; Denham, M.; Yeager, C.; Santschi, P.

    2013-05-16

    Iodine-129 is one of the key risk drivers for several Savannah River Site (SRS) performance assessments (PA), including that for the Low-Level Waste Disposal Facility in E-Area. In an effort to reduce the uncertainty associated with the conceptual model and the input values used in PA, several studies have recently been conducted dealing with radioiodine geochemistry at the SRS. The objective of this report was to review these recent studies and evaluate their implications on SRS PA calculations. For the first time, these studies measured iodine speciation in SRS groundwater and provided technical justification for assuming the presence of more strongly sorbing species (iodate and organo-iodine), and measured greater iodine sediment sorption when experiments included these newly identified species; specifically they measured greater sorption coefficients (K{sub d} values: the concentration ratio of iodine on the solid phase divided by the concentration in the aqueous phase). Based on these recent studies, new best estimates were proposed for future PA calculations. The new K{sub d} values are greater than previous recommended values. These proposed K{sub d} values reflect a better understanding of iodine geochemistry in the SRS subsurface environment, which permits reducing the associated conservatism included in the original estimates to account for uncertainty. Among the key contributing discoveries supporting the contention that the K{sub d} values should be increased are that: 1) not only iodide (I{sup -}), but also the more strongly sorbing iodate (IO{sub 3}{sup -}) species exists in SRS groundwater (average total iodine = 15% iodide, 42% iodate, and 43% organoiodine), 2) when iodine was added as iodate, the measured K{sub d} values were 2 to 6 times greater than when the iodine was added as iodide, and perhaps most importantly, 3) higher desorption (10 to 20 mL/g) than (ad)sorption (all previous studies) K{sub d} values were measured. The implications of this

  6. The Phosphatidylserine and Phosphatidylethanolamine Receptor CD300a Binds Dengue Virus and Enhances Infection

    PubMed Central

    Carnec, Xavier; Meertens, Laurent; Dejarnac, Ophélie; Perera-Lecoin, Manuel; Hafirassou, Mohamed Lamine; Kitaura, Jiro; Ramdasi, Rasika; Schwartz, Olivier

    2015-01-01

    ABSTRACT Dengue virus (DENV) is the etiological agent of the major human arboviral disease. We previously demonstrated that the TIM and TAM families of phosphatidylserine (PtdSer) receptors involved in the phagocytosis of apoptotic cells mediate DENV entry into target cells. We show here that human CD300a, a recently identified phospholipid receptor, also binds directly DENV particles and enhances viral entry. CD300a facilitates infection of the four DENV serotypes, as well as of other mosquito-borne viruses such as West Nile virus and Chikungunya virus. CD300a acts as an attachment factor that enhances DENV internalization through clathrin-mediated endocytosis. CD300a recognizes predominantly phosphatidylethanolamine (PtdEth) and to a lesser extent PtdSer associated with viral particles. Mutation of residues in the IgV domain critical for phospholipid binding abrogate CD300a-mediated enhancement of DENV infection. Finally, we show that CD300a is expressed at the surface of primary macrophages and anti-CD300a polyclonal antibodies partially inhibited DENV infection of these cells. Overall, these data indicate that CD300a is a novel DENV binding receptor that recognizes PtdEth and PtdSer present on virions and enhance infection. IMPORTANCE Dengue disease, caused by dengue virus (DENV), has emerged as the most important mosquito-borne viral disease of humans and is a major global health concern. The molecular bases of DENV-host cell interactions during virus entry are poorly understood, hampering the discovery of new targets for antiviral intervention. We recently discovered that the TIM and TAM proteins, two receptor families involved in the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, interact with DENV particles-associated PtdSer through a mechanism that mimics the recognition of apoptotic cells and mediate DENV infection. In this study, we show that CD300a, a novel identified phospholipid receptor, mediates DENV infection. CD300a

  7. Contaminated Sediment

    EPA Pesticide Factsheets

    Contaminated sediments are a significant problem in the Great Lakes basin. Persistent high concentrations of contaminants in the bottom sediments of rivers and harbors pose risks to aquatic organisms, wildlife, and humans.

  8. Active Marine Subsurface Bacterial Population Composition in Low Organic Carbon Environments from IODP Expedition 320

    NASA Astrophysics Data System (ADS)

    Shepard, A.; Reese, B. K.; Mills, H. J.; IODP Expedition 320 Shipboard Science Party

    2011-12-01

    The marine subsurface environment contains abundant and active microorganisms. These microbial populations are considered integral players in the marine subsurface biogeochemical system with significance in global geochemical cycles and reservoirs. However, variations in microbial community structure, activity and function associated with the wide-ranging sedimentary and geochemical environments found globally have not been fully resolved. Integrated Ocean Drilling Program Expedition 320 recovered sediments from site U1332. Two sampling depths were selected for analysis that spanned differing lithological units in the sediment core. Sediments were composed of mostly clay with zeolite minerals at 8 meters below sea floor (mbsf). At 27 mbsf, sediments were composed of alternating clayey radiolarian ooze and nannofossil ooze. The concentration of SO42- had little variability throughout the core and the concentration of Fe2+ remained close to, or below, detection limits (0.4 μM). Total organic carbon content ranged from a low of 0.03 wt% to a high of 0.07 wt% between 6 and 30 mbsf providing an opportunity to evaluate marine subsurface microbial communities under extreme electron donor limiting conditions. The metabolically active fraction of the bacterial population was isolated by the extraction and amplification of 16S ribosomal RNA. Pyrosequencing of 16S rRNA transcripts and subsequent bioinformatic analyses provided a robust data set (15,931 total classified sequences) to characterize the community at a high resolution. As observed in other subsurface environments, the overall diversity of active bacterial populations decreased with depth. The population shifted from a diverse but evenly distributed community at approximately 8 mbsf to a Firmicutes dominated population at 27 mbsf (80% of sequences). A total of 95% of the sequences at 27 mbsf were grouped into three genera: Lactobacillus (phylum Firmicutes) at 80% of the total sequences, Marinobacter (phylum

  9. Contaminant Transport Through Subsurface Material from the DOE Hanford Reservation

    SciTech Connect

    Pace, M.N.; Mayes, M.A.; Jardine, P.M.; Fendorf, S.E.; Nehlhorn, T.L.; Yin, X.P.; Ladd, J.; Teerlink, J.; Zachara, J.M.

    2003-03-26

    Accelerated migration of contaminants in the vadose zone has been observed beneath tank farms at the U.S. Department of Energy's Hanford Reservation. This paper focuses on the geochemical processes controlling the fate and transport of contaminants in the sediments beneath the Hanford tank farms. Laboratory scale batch sorption experiments and saturated transport experiments were conducted using reactive tracers U(VI), Sr, Cs, Co and Cr(VI) to investigate geochemical processes controlling the rates and mechanisms of sorption to Hanford subsurface material. Results indicate that the rate of sorption is influenced by changes in solution chemistry such as ionic strength, pH and presence of competing cations. Sediment characteristics such as mineralogy, iron content and cation/anion exchange capacity coupled with the dynamics of flow impact the number of sites available for sorption. Investigative approaches using a combination of batch and transport experiments will contribute to the conceptual and Hanford vadose zone.

  10. Method of installing subsurface barrier

    SciTech Connect

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2007-10-09

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  11. Aquatic Sediments.

    ERIC Educational Resources Information Center

    Sanville, W. D.; And Others

    1978-01-01

    Presents a literature review of aquatic sediments and its effect upon water quality, covering publications of 1976-77. This review includes: (1) sediment water interchange; (2) chemical and physical characterization; and (3) heavy water in sediments. A list of 129 references is also presented. (HM)

  12. INL Subsurface Wireless Sensor Platform

    SciTech Connect

    Dennis C. Kunerth; John M. Svoboda; James T. Johnson

    2005-10-01

    The Idaho National Laboratory is developing a versatile micro-power sensor interface platform for periodic subsurface sensing of environmental variables important to waste disposal sites such as volumetric moisture, water potential, and temperature. The key characteristics of the platform architecture are that the platform is passive until externally energized --no internal power source is required -- and that it communicates with a "reader" via short-range telemetry - no wires penetrate the subsurface. Other significant attributes include the potential for a long service life and a compact size that makes it well suited for retrofitting existing landfill structures. Functionally, the sensor package is "read" by a short-range induction coil that activates and powers the sensor platform as well as detects the sensor output via a radio frequency signal generated by the onboard programmable interface controller microchip. As a result, the platform has a functional subsurface communication range of approximately 10 to 12 ft. and can only accept sensors that require low power to operate.

  13. Deep subsurface life from North Pond: Enrichment, isolation, characterization and genomes of heterotrophic bacteria

    DOE PAGES

    Russell, Joseph A.; Leon-Zayas, Rosa; Wrighton, Kelly; ...

    2016-05-10

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic watercolumn west of the Mid-Atlantic Ridge at 22° N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sedimentmore » column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. Furthermore, the cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface.« less

  14. Geomorphic factors related to the persistence of subsurface oil from the Exxon Valdez oil spill

    USGS Publications Warehouse

    Nixon, Zachary; Michel, Jacqueline; Hayes, Miles O.; Irvine, Gail V.; Short, Jeffrey

    2013-01-01

    Oil from the 1989 Exxon Valdez oil spill has persisted along shorelines of Prince William Sound, Alaska, for more than two decades as both surface and subsurface oil residues. To better understand the distribution of persistent subsurface oil and assess the potential need for further restoration, a thorough and quantitative understanding of the geomorphic factors controlling the presence or absence of subsurface oil is required. Data on oiling and geomorphic features were collected at 198 sites in Prince William Sound to identify and quantify the relationships among these geomorphic factors and the presence and absence of persistent subsurface oil. Geomorphic factors associated with the presence of subsurface oil were initial oil exposure, substrate permeability, topographic slope, low exposure to waves, armoring on gravel beaches, tombolos, natural breakwaters, and rubble accumulations. Geomorphic factors associated with the absence of subsurface oil were impermeable bedrock; platforms with thin sediment veneer; fine-grained, well-sorted gravel beaches with no armor; and low-permeability, raised bay-bottom beaches. Relationships were found between the geomorphic and physical site characteristics and the likelihood of encountering persistent subsurface oiling at those sites. There is quantitative evidence of more complex interactions between the overall wave energy incident at a site and the presence of fine-scale geomorphic features that may have provided smaller, local wave energy sheltering of oil. Similarly, these data provide evidence for interactions between the shoreline slope and the presence of angular rubble, with decreased likelihood for encountering subsurface oil at steeply sloped sites except at high-angle sheltered rubble shoreline locations. These results reinforce the idea that the interactions of beach permeability, stability, and site-specific wave exposure are key drivers for subsurface oil persistence in exposed and intermittently exposed mixed

  15. Laboratory and Field Evidence for Long-Term Starvation Survival of Microorganisms in Subsurface Terrestrial Environments

    SciTech Connect

    Kieft, T.L.; Murphy, E.M.; Amy, P.S.; Haldeman, D.L.; Ringelberg, D. B. |

    1997-12-31

    BIOGEOCHEMICAL MODELING OF GROUNDWATER FLOW AND NUTRIENT FLUX IN SUBSURFACE ENVIRONMENTS INDICATES THAT INHABITANT MICROORGANISMS EXPERIENCE SEVERE NUTRIENT LIMITATION. USING LABORATORY AND FIELD METHODS, WE HAVE BEEN TESTING STARVATION SURVIVAL IN SUBSURFACE MICROORGANISMS. IN MICROCOSM EXPERIMENTS, WE HAVE SHOWN THAT STRAINS OF TWO COMMONLY ISOLATED SUBSURFACE GENERA, ARTHROBACTER AND PSEUDOMONAS, ARE ABLE TO MAINTAIN VIABILITY IN LOW-NUTRIENT, NATURAL SUBSURFACE SEDIMENTS FOR OVER ONE YEAR. THESE NON-SPORE-FORMING BACTERIA UNDERGO RAPID INITIAL MINIATURIZATION FOLLOWED BY A STABILIZATION OF CELL SIZE. MEMBRANE LIPID PHOSPHOLIPID FATTY ACID (PLFA) PROFILES OF THE PSEUDOMONAS ARE CONSISTENT WITH ADAPTATION TO NUTRIENT STRESS; ARTHROBACTER APPARENTLY RESPONDS TO NUTRIENT DEPRIVATION WITHOUT ALTERING MEMBRANE PLFA. TO TEST SURVIVABILITY OF MICROORGANISMS OVER A GEOLOGIC TIME SCALE, WE CHARACTERIZED MICROBIAL COMMUNITIES IN A SEQUENCE OF UNSATURATED SEDIMENTS RANGING IN AGE FROM MODEM TO {gt}780,000 years. Sediments were relatively uniform silts in Eastern Washington State. Porewater ages at depth (measured by the chloride mass-balance approach) were as old as 3,600 years. Microbial abundance, biomass, and activities (measured by direct counts, culture counts, total PLFAs, and radiorespirometry) declined with sediment age. The pattern is consistent with laboratory microcosm studies of Microbial survival: rapid short-term change followed by long-term survival of a proportion of cells. Even the oldest sediments evinced a small but viable Microbial community. Microbial survival appeared to be a function of sediment age. Porewater age appeared to influence the markup of surviving communities, as indicated by PLFA profiles. Sites with different Porewater recharge rates and patterns of Pleistocene flooding had different communities.

  16. Subsurface damage from oblique impacts into low-impedance layers

    NASA Astrophysics Data System (ADS)

    Stickle, A. M.; Schultz, P. H.

    2012-07-01

    Layered planetary surfaces occur ubiquitously in the solar system, where sedimentary sequences or icy layers overlay crystalline bedrock. Previous experimental studies investigated how the presence of weak layer overlying a strong basement affects crater morphology, subsurface damage and soft-sediment compression. Numerical studies generally focus on the final morphology as a function of thicknesses and burial depths of weak layers. In field studies of impact craters, the shock state of minerals is a key metric. Here, we evaluate the effect of a surficial low-impedance layer on peak pressure magnitudes and consequent damage extent in the competent substrate. Laboratory experiments coupled with 3D CTH models of oblique (30° from horizontal) hypervelocity impacts at laboratory and planetary scales show that surface layers with a thickness on the order of the projectile diameter shield the underlying surface and absorb/scatter ˜70% of the impact energy. Numerical simulations reveal that surficial layers reduce peak pressure magnitudes within the subsurface by ˜60-70%, while damage in the substrate is due to shear failure. Sedimentary layers are more efficient shields than icy layers, but both reduce the extent of subsurface damage and the resulting shock levels recorded by minerals. These results indicate that a thin surficial low impedance layer mitigates the expression of shocked minerals in the substrate even when a structural response is still observed.

  17. Drilling Automation Demonstrations in Subsurface Exploration for Astrobiology

    NASA Technical Reports Server (NTRS)

    Glass, Brian; Cannon, H.; Lee, P.; Hanagud, S.; Davis, K.

    2006-01-01

    This project proposes to study subsurface permafrost microbial habitats at a relevant Arctic Mars-analog site (Haughton Crater, Devon Island, Canada) while developing and maturing the subsurface drilling and drilling automation technologies that will be required by post-2010 missions. It builds on earlier drilling technology projects to add permafrost and ice-drilling capabilities to 5m with a lightweight drill that will be automatically monitored and controlled in-situ. Frozen cores obtained with this drill under sterilized protocols will be used in testing three hypotheses pertaining to near-surface physical geology and ground H2O ice distribution, viewed as a habitat for microbial life in subsurface ice and ice-consolidated sediments. Automation technologies employed will demonstrate hands-off diagnostics and drill control, using novel vibrational dynamical analysis methods and model-based reasoning to monitor and identify drilling fault states before and during faults. Three field deployments, to a Mars-analog site with frozen impact crater fallback breccia, will support science goals, provide a rigorous test of drilling automation and lightweight permafrost drilling, and leverage past experience with the field site s particular logistics.

  18. Deep Sequencing of Subseafloor Eukaryotic rRNA Reveals Active Fungi across Marine Subsurface Provinces

    PubMed Central

    Orsi, William; Biddle, Jennifer F.; Edgcomb, Virginia

    2013-01-01

    The deep marine subsurface is a vast habitat for microbial life where cells may live on geologic timescales. Because DNA in sediments may be preserved on long timescales, ribosomal RNA (rRNA) is suggested to be a proxy for the active fraction of a microbial community in the subsurface. During an investigation of eukaryotic 18S rRNA by amplicon pyrosequencing, unique profiles of Fungi were found across a range of marine subsurface provinces including ridge flanks, continental margins, and abyssal plains. Subseafloor fungal populations exhibit statistically significant correlations with total organic carbon (TOC), nitrate, sulfide, and dissolved inorganic carbon (DIC). These correlations are supported by terminal restriction length polymorphism (TRFLP) analyses of fungal rRNA. Geochemical correlations with fungal pyrosequencing and TRFLP data from this geographically broad sample set suggests environmental selection of active Fungi in the marine subsurface. Within the same dataset, ancient rRNA signatures were recovered from plants and diatoms in marine sediments ranging from 0.03 to 2.7 million years old, suggesting that rRNA from some eukaryotic taxa may be much more stable than previously considered in the marine subsurface. PMID:23418556

  19. Deep sequencing of subseafloor eukaryotic rRNA reveals active Fungi across marine subsurface provinces.

    PubMed

    Orsi, William; Biddle, Jennifer F; Edgcomb, Virginia

    2013-01-01

    The deep marine subsurface is a vast habitat for microbial life where cells may live on geologic timescales. Because DNA in sediments may be preserved on long timescales, ribosomal RNA (rRNA) is suggested to be a proxy for the active fraction of a microbial community in the subsurface. During an investigation of eukaryotic 18S rRNA by amplicon pyrosequencing, unique profiles of Fungi were found across a range of marine subsurface provinces including ridge flanks, continental margins, and abyssal plains. Subseafloor fungal populations exhibit statistically significant correlations with total organic carbon (TOC), nitrate, sulfide, and dissolved inorganic carbon (DIC). These correlations are supported by terminal restriction length polymorphism (TRFLP) analyses of fungal rRNA. Geochemical correlations with fungal pyrosequencing and TRFLP data from this geographically broad sample set suggests environmental selection of active Fungi in the marine subsurface. Within the same dataset, ancient rRNA signatures were recovered from plants and diatoms in marine sediments ranging from 0.03 to 2.7 million years old, suggesting that rRNA from some eukaryotic taxa may be much more stable than previously considered in the marine subsurface.

  20. Sources of suspended sediment in the Lower Roanoke River, NC

    NASA Astrophysics Data System (ADS)

    Jalowska, A. M.; McKee, B. A.; Rodriguez, A. B.; Laceby, J. P.

    2015-12-01

    The Lower Roanoke River, NC, extends 220 km from the fall line to the bayhead delta front in the Albemarle Sound. The Lower Roanoke is almost completely disconnected from the upper reaches by a series of dams, with the furthest downstream dam located at the fall line. The dams effectively restrict the suspended sediment delivery from headwaters, making soils and sediments from the Lower Roanoke River basin, the sole source of suspended sediment. In flow-regulated rivers, bank erosion, especially mass wasting, is the major contributor to the suspended matter. Additional sources of the suspended sediment considered in this study are river channel, surface soils, floodplain surface sediments, and erosion of the delta front and prodelta. Here, we examine spatial and temporal variations in those sources. This study combined the use of flow and grain size data with a sediment fingerprinting method, to examine the contribution of surface and subsurface sediments to the observed suspended sediment load along the Lower Roanoke River. The fingerprinting method utilized radionuclide tracers 210Pb (natural atmospheric fallout), and 137Cs (produced by thermonuclear bomb testing). The contributions of surface and subsurface sources to the suspended sediment were calculated with 95% confidence intervals using a Monte-Carlo numerical mixing model. Our results show that with decreasing river slope and changing hydrography along the river, the contribution of surface sediments increases and becomes a main source of sediments in the Roanoke bayhead delta. At the river mouth, the surface sediment contribution decreases and is replaced by sediments eroded from the delta front and prodelta. The area of high surface sediment contribution is within the middle and upper parts of the delta, which are considered net depositional. Our study demonstrates that floodplains, often regarded to be a sediment sink, are also a sediment source, and they should be factored into sediment, carbon and

  1. Subsurface North Atlantic warming as a trigger of rapid cooling events: evidence from the early Pleistocene (MIS 31-19)

    NASA Astrophysics Data System (ADS)

    Hernández-Almeida, I.; Sierro, F.-J.; Cacho, I.; Flores, J.-A.

    2015-04-01

    Subsurface water column dynamics in the subpolar North Atlantic were reconstructed in order to improve the understanding of the cause of abrupt ice-rafted detritus (IRD) events during cold periods of the early Pleistocene. We used paired Mg / Ca and δ18O measurements of Neogloboquadrina pachyderma (sinistral - sin.), deep-dwelling planktonic foraminifera, to estimate the subsurface temperatures and seawater δ18O from a sediment core from Gardar Drift, in the subpolar North Atlantic. Carbon isotopes of benthic and planktonic foraminifera from the same site provide information about the ventilation and water column nutrient gradient. Mg / Ca-based temperatures and seawater δ18O suggest increased subsurface temperatures and salinities during ice-rafting, likely due to northward subsurface transport of subtropical waters during periods of weaker Atlantic Meridional Overturning Circulation (AMOC). Planktonic carbon isotopes support this suggestion, showing coincident increased subsurface ventilation during deposition of IRD. Subsurface accumulation of warm waters would have resulted in basal warming and break-up of ice-shelves, leading to massive iceberg discharges in the North Atlantic. The release of heat stored at the subsurface to the atmosphere would have helped to restart the AMOC. This mechanism is in agreement with modelling and proxy studies that observe a subsurface warming in the North Atlantic in response to AMOC slowdown during Marine Isotope Stage (MIS) 3.

  2. Archaeal populations in two distinct sedimentary facies of the subsurface of the Dead Sea.

    PubMed

    Thomas, C; Ionescu, D; Ariztegui, D

    2014-10-01

    Archaeal metabolism was studied in aragonitic and gypsum facies of the Dead Sea subsurface using high-throughput DNA sequencing. We show that the communities are well adapted to the peculiar environment of the Dead Sea subsurface. They harbor the necessary genes to deal with osmotic pressure using high- and low-salt-in strategies, and to cope with unusually high concentrations of heavy metals. Methanogenesis was identified for the first time in the Dead Sea and appears to be an important metabolism in the aragonite sediment. Fermentation of residual organic matter, probably performed by some members of the Halobacteria class is common to both types of sediments. The latter group represents more than 95% of the taxonomically identifiable Archaea in the metagenome of the gypsum sediment. The potential for sulfur reduction has also been revealed and is associated in the sediment with EPS degradation and Fe-S mineralization as revealed by SEM imaging. Overall, we show that distinct communities of Archaea are associated with the two different facies of the Dead Sea, and are adapted to the harsh chemistry of its subsurface, in different ways.

  3. Burrowing and subsurface locomotion in anguilliform fish: behavioral specializations and mechanical constraints.

    PubMed

    Herrel, Anthony; Choi, Hon Fai; Dumont, Elizabeth; De Schepper, Natalie; Vanhooydonck, Bieke; Aerts, Peter; Adriaens, Dominique

    2011-04-15

    Fish swimming is probably one of the most studied and best understood locomotor behaviors in vertebrates. However, many fish also actively exploit sediments. Because of their elongate body shape, anguilliform fishes are not only efficient swimmers but also very maneuverable. Consequently, many species live in complexly structured environments near the bottom and many are known to burrow into the sediment. To better understand burrowing and subsurface locomotion in anguilliform fish we provide descriptive kinematic data on subsurface locomotion in a burrowing eel (Pisodonophis boro) using videofluoroscopy. We also measured the maximal forces that can be exerted by this species during head-first and tail-first burrowing, and explored the implications of head-first burrowing on mechanical stress distribution in the skull. Our data show that P. boro uses lateral undulation to penetrate and move in sandy sediments under water. The kinematics of subsurface locomotion are different from those observed during swimming and are characterized by a very high slip factor. These observations differ considerably from recently published data in terrestrial sand-swimming lizards, and suggest that the sediment behaves like a solid rather than a frictional fluid. Finally, our finite element models show that the cranial shape and structure in the head-first burrowing P. boro is mechanically more suited for head-first burrowing than that of an obligate tail-first burrowing species, Heteroconger hassi.

  4. Introduction: energy and the subsurface.

    PubMed

    Christov, Ivan C; Viswanathan, Hari S

    2016-10-13

    This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection.This article is part of the themed issue 'Energy and the subsurface'.

  5. Phylogenetic relationships among subsurface microorganisms

    SciTech Connect

    Nierzwicki-Bauer, S.A.

    1991-01-01

    This project involves the development of group specific 16S ribosomal RNA-targeted oligonucleotide hybridization probes for the rapid detection of specific types of subsurface organisms (e.g., groups of microbes that share certain physiological traits). Major accomplishments for the period of 6/91 to 12/1/91 are described. Nine new probes have been synthesized on the basis of published 16S rRNA sequence data from the Ribosomal Database Project. We have initiated rapid screening of many of the subsurface microbial isolates obtained from the P24 borehole at the Savannah River Site. To date, we have screened approximately 50% of the isolates from P24. We have optimized our {und in situ} hybridization technique, and have developed a cell blot hybridization technique to screen 96 samples on a single blot. This is much faster than reading 96 individual slides. Preliminary experiments have been carried out which indicate specific nutrients can be used to amplify rRNA only in those organisms capable of metabolizing those nutrients. 1 tab., 2 figs.

  6. PPARβ/δ activation of CD300a controls intestinal immunity

    PubMed Central

    Tanaka, Toshiya; Tahara-Hanaoka, Satoko; Nabekura, Tsukasa; Ikeda, Kaori; Jiang, Shuying; Tsutsumi, Shuichi; Inagaki, Takeshi; Magoori, Kenta; Higurashi, Takuma; Takahashi, Hirokazu; Tachibana, Keisuke; Tsurutani, Yuya; Raza, Sana; Anai, Motonobu; Minami, Takashi; Wada, Youichiro; Yokote, Koutaro; Doi, Takefumi; Hamakubo, Takao; Auwerx, Johan; Gonzalez, Frank J.; Nakajima, Atsushi; Aburatani, Hiroyuki; Naito, Makoto; Shibuya, Akira; Kodama, Tatsuhiko; Sakai, Juro

    2014-01-01

    Macrophages are important for maintaining intestinal immune homeostasis. Here, we show that PPARβ/δ (peroxisome proliferator-activated receptor β/δ) directly regulates CD300a in macrophages that express the immunoreceptor tyrosine based-inhibitory motif (ITIM)-containing receptor. In mice lacking CD300a, high-fat diet (HFD) causes chronic intestinal inflammation with low numbers of intestinal lymph capillaries and dramatically expanded mesenteric lymph nodes. As a result, these mice exhibit triglyceride malabsorption and reduced body weight gain on HFD. Peritoneal macrophages from Cd300a−/− mice on HFD are classically M1 activated. Activation of toll-like receptor 4 (TLR4)/MyD88 signaling by lipopolysaccharide (LPS) results in prolonged IL-6 secretion in Cd300a−/− macrophages. Bone marrow transplantation confirmed that the phenotype originates from CD300a deficiency in leucocytes. These results identify CD300a-mediated inhibitory signaling in macrophages as a critical regulator of intestinal immune homeostasis. PMID:24958459

  7. 46 CFR 308.518 - Standard optional endorsement No. 1, Form MA-300-A.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Standard optional endorsement No. 1, Form MA-300-A. 308.518 Section 308.518 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Open Policy War Risk Cargo Insurance §...

  8. The evolution of cave systems from the surface to subsurface

    SciTech Connect

    Loucks, R.G.; Handford, C.R.

    1996-12-31

    Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amounts of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.

  9. The evolution of cave systems from the surface to subsurface

    SciTech Connect

    Loucks, R.G. ); Handford, C.R. )

    1996-01-01

    Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amounts of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.

  10. Preliminary Investigation of Linkages Between Arctic Pingos and Subsurface Stratigraphy

    NASA Astrophysics Data System (ADS)

    Casavant, R.; Skirvin, S.; Patel, C.; Burr, D.

    2008-12-01

    This NASA-SETI supported study investigates the distribution of pingos (elliptically-shaped ice-rich topographic mounds) across 2300 square kilometers of the central coastal plain of Arctic Alaska in relation to the shallow geological framework that exists immediately beneath them. Pingos in the central North Slope of Alaska are classified as being of the closed or hydrostatic type. Their genesis is often assigned to freezing and cryogenic uplift of near-surface saturated thaw lake sediments that are exposed as lakes are drained and/or become choked with sediments. Although thaw lakes appear rather ubiquitous across the study area, pingos do not. Pingo distributions can be categorized as either clusters of elements or as relatively dispersed. Spatial statistical analysis reveals that pingo distribution is non-random and clustered. The analysis also took into account that pingo distribution is a function of preferential preservation between modern rivers channels that cross the study area. Pingo distributions and frequency were tested in relation to the location and type of stratigraphic and sedimentological features that characterized the shallow subsurface across the study area. Subsurface interpretation was derived mostly from oil well wireline logs. Gamma ray logs for more than 160 wells were used to define, correlate and assess the connectivity and conductivity of shallow and near-surface stratigraphic units between wells. Assessed also were major facies changes and the type and locations of subsurface structures such as major basement-to-surface faults and folds. The surface and near-surface truncation and subcropping of tilted, alternating units of permeable coarse-grained and confining fine- grained units were also mapped in relation to pingo locations. Preliminary and intriguing findings will be presented which contribute to the hypothesis that pingo genesis, location, and variations in morphology could be, in part, linked to a well-documented and active

  11. A field evaluation of subsurface and surface runoff. II. Runoff processes

    USGS Publications Warehouse

    Pilgrim, D.H.; Huff, D.D.; Steele, T.D.

    1978-01-01

    Combined use of radioisotope tracer, flow rate, specific conductance and suspended-sediment measurements on a large field plot near Stanford, California, has provided more detailed information on surface and subsurface storm runoff processes than would be possible from any single approach used in isolation. Although the plot was surficially uniform, the runoff processes were shown to be grossly nonuniform, both spatially over the plot, and laterally and vertically within the soil. The three types of processes that have been suggested as sources of storm runoff (Horton-type surface runoff, saturated overland flow, and rapid subsurface throughflow) all occurred on the plot. The nonuniformity of the processes supports the partial- and variable-source area concepts. Subsurface storm runoff occurred in a saturated layer above the subsoil horizon, and short travel times resulted from flow through macropores rather than the soil matrix. Consideration of these observations would be necessary for physically realistic modeling of the storm runoff process. ?? 1978.

  12. Microbial processes and subsurface contaminants

    NASA Astrophysics Data System (ADS)

    Molz, Fred J.

    A Chapman Conference entitled “Microbial Processes in the Transport, Fate, and In Situ Treatment of Subsurface Contaminants” was held in Snowbird, Utah, October 1-3, 1986. Members of the program committee and session chairmen were Lenore Clesceri (Rensselaer Polytechnic Institute, Troy, N.Y.), David Gibson (University of Texas, Austin), James Mercer (GeoTrans, Inc., Herndon , Va.), Donald Michelsen (Virginia Polytechnic Institute and State University, Blacksburg), Fred Molz (Auburn University, Auburn, Ala.), Bruce Rittman (University of Illinois, Urbana), Gary Sayler (University of Tennessee, Knoxville), and John T. Wilson (U.S. Environmental Protection Agency, Ada, Okla.). The following report attempts to highlight the six sessions that constituted the conference. For additional information, including a bound summary and abstracts, contact Fred J. Molz, Civil Engineering Department, Auburn University, AL 36849 (telephone: 205-826-4321).

  13. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-01-01

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site's microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog [reg sign] evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog[reg sign] activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  14. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-12-31

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site`s microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog {reg_sign} evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog{reg_sign} activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  15. Structure and function of subsurface microbial communities affecting radionuclide transport and bioimmobilization

    SciTech Connect

    Kostka, Joel E.; Prakash, Om; Green, Stefan J.; Akob, Denise; Jasrotia, Puja; Kerkhof, Lee; Chin, Kuk-Jeong; Sheth, Mili; Keller, Martin; Venkateswaran, Amudhan; Elkins, James G.; Stucki, Joseph W.

    2012-05-01

    Our objectives were to: 1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), 2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and 3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations. Field sampling was conducted at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee. The ORFRC subsurface is exposed to mixed contamination predominated by uranium and nitrate. In short, we effectively addressed all 3 stated objectives of the project. In particular, we isolated and characterized a large number of novel anaerobes with a high bioremediation potential that can be used as model organisms, and we are now able to quantify the function of subsurface sedimentary microbial communities in situ using state-of-the-art gene expression methods (molecular proxies).

  16. On using rational enzyme redesign to improve enzyme-mediated microbial dehalogenation of recalcitrant substances in deep-subsurface environments

    SciTech Connect

    Ornstein, R.L.

    1993-06-01

    Heavily halogenated hydrocarbons are one of the most prevalent classes of man-made recalcitrant environmental contaminants and often make their way into subsurface environments. Biodegradation of heavily chlorinated compounds in the deep subsurface often occurs at extremely slow rates because native enzymes of indigenous microbes are unable to efficiently metabolize such synthetic substances. Cost-effective engineering solutions do not exist for dealing with disperse and recalcitrant pollutants in the deep subsurface (i.e., ground water, soils, and sediments). Timely biodegradation of heavily chlorinated compounds in the deep subsurface may be best accomplished by rational redesign of appropriate enzymes that enhance the ability of indigenous microbes to metabolize these substances. The isozyme family cytochromes P450 are catalytically very robust and are found in all aerobic life forms and may be active in may anaerobes as well. The author is attempting to demonstrate proof-of-principle rational enzyme redesign of cytochromes P450 to enhance biodehalogenation.

  17. Comparison of sediment profile image data with profiles of oxygen and Eh from sediment cores

    NASA Astrophysics Data System (ADS)

    Diaz, Robert J.; Trefry, John H.

    2006-10-01

    A study of oil and gas development in the Gulf of Mexico provided a unique opportunity to compare data from sediment profile images (SPI) with that of sediment cores collected at locations in the central Gulf of Mexico from 1034 to 1175 m. Variables measured from SPI included sediment grain-size, sediment texture, apparent depth of oxygen penetration (aDOP) into the sediments, and parameters related to biogenic activity (tubes, burrows, feeding pits or mounds, and subsurface feeding voids). Variables measured from the sediment cores included sedimentation rate, dissolved oxygen profiles, and redox potential (Eh). There was a high degree of concordance between the two data sets based on correlation analysis. For example, the correlation between aDOP and maximum penetration of oxygen into the sediment was 0.69. For deep-sea sediment, SPI provides a means by which general geochemical conditions of near surface sediment can be remotely assessed providing a quick method for mapping surficial geochemistry over large areas.

  18. Desulfotomaculum spp. and related gram-positive sulfate-reducing bacteria in deep subsurface environments

    PubMed Central

    Aüllo, Thomas; Ranchou-Peyruse, Anthony; Ollivier, Bernard; Magot, Michel

    2013-01-01

    Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2) and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review. PMID:24348471

  19. Subsurface geology of Kansai International Airport: sequence related to global glacial - interglacial cycles and island tectonics

    NASA Astrophysics Data System (ADS)

    Takemura, K.; Kitada, N.; Furudoi, T.; Nakaseko, K.

    2007-12-01

    Tectonic sedimentary basins aligned in the central part of Japan during Quaternary . Thick sediments deposited in these basins provide useful records of climatic changes and tectonics throughout Quaternary. The Osaka sedimentary basin including Osaka Bay and area of Kansai International Airport is one of them. The Quaternary Osaka sedimentary basin has developed at an eastern contractional bend of a major transcurrent fault system named the Median Tectonic Line, which divides the southwest Japan arc. The thickness of Pliocene - Pleistocene sediments reaches to ca 3500m at the deepest part. These sequences are called the Osaka Group and are distributed in the Osaka Bay and exposed in the surrounding mountain areas. The Osaka Group is characterized by alternating sequences of marine and nonmarine strata. The subsurface sediments of Kansai International Airport (KIA) is composed mainly of Pliocene - Pleistocene sediments, which is characterized by alternating sequences of marine and nonmarine strata related to glacial - interglacial cycles. . The stratigraphy at KIA was established by micropaleontological, tephrochronological and magnetostratigraphical method. The sedimentary sequence at KIX is divided into two main units (Kukojima and Sennanoki Formations in ascending order) with the uncomformity within two units. Although thick marine clay units are mainly of the subsurface sequence, characteristics of coarser sediment units have an important role of moving of water during construction of the reclaimed land.

  20. Deep subsurface life from North Pond: Enrichment, isolation, characterization and genomes of heterotrophic bacteria

    SciTech Connect

    Russell, Joseph A.; Leon-Zayas, Rosa; Wrighton, Kelly; Biddle, Jennifer F.

    2016-05-10

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic watercolumn west of the Mid-Atlantic Ridge at 22° N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. Furthermore, the cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface.

  1. Plutonium contamination issues in Hanford soils and sediments: Discharges from the Z-Plant (PFP) complex

    NASA Astrophysics Data System (ADS)

    Felmy, Andrew R.; Cantrell, Kirk J.; Conradson, Steven D.

    Beginning in 1945, weapons production activities at the Hanford Nuclear Reservation resulted in the discharge of large quantities of Pu and other transuranic elements to the subsurface. The vast majority of the transuranics was disposed in the Hanford central plateau (200 areas) predominately associated with activities at the Z-Plant (Plutonium Finishing Plant) complex. In the past Pu and Am migrated deep into the subsurface at certain locations, although Pu and other transuranics are not currently being detected in significant concentration in any associated groundwaters. Evaluation of the chemical form of the transuranics in the subsurface along with determining the mechanism(s) of the past subsurface migration is important in establishing strategies for long-term site management practices. Unfortunately, the chemical form of the transuranics in the deep subsurface sediments and the past mechanism of vertical migration remain largely unknown. However, initial studies performed as part of this research indicate that the chemical form of Pu can vary from disposal site to disposal site depending upon the waste type and the chemical form can also differ between surface sediments and deep subsurface sediments at the same site. This paper present a summary of the different waste types and locations where transuranics were disposed, the factors that could have lead to subsurface migration via different transport vectors, the information currently available on the chemical form of Pu in the subsurface, and a summary of current research needs.

  2. Remediation of contaminated subsurface materials by a metal-reducing bacterium

    SciTech Connect

    Gorby, Y.A.; Amonette, J.E.; Fruchter, J.S.

    1994-11-01

    A biotic approach for remediating subsurface sediments and groundwater contaminated with carbon tetrachloride (CT) and chromium was evaluated. Cells of the Fe(iii)-reducing bacterium strain BrY were added to sealed, anoxic flasks containing Hanford groundwater, natural subsurface sediments, and either carbon tetrachloride, CT, or oxidized chromium, Cr(VI). With lactate as the electron donor, BrY transformed CT to chloroform (CF), which accumulated to about 1 0 % of the initial concentration of CT. The remainder of the CT was transformed to unidentified, nonvolatile compounds. Transformation of CT by BrY was an indirect process Cells reduced solid phase Fe(ill) to chemically reactive FE(II) that chemically transformed the chlorinated contaminant. Cr(VI), in contrast, was reduced by a direct enzymatic reaction in the presence or absence of Fe(III)-bearing sediments. These results demonstrate that Fe(ill)-reducing bacteria provide potential for transforming CT and for reducing CR(VI) to less toxic Cr(III). Technologies for stimulating indigenous populations of metal-reducing bacteria or for introducing specific metal-reducing bacteria to the subsurface are being investigated.

  3. Sediment Quality Characterization Naval Station San Diego

    DTIC Science & Technology

    1999-01-01

    Neanthes sp. Sediment % Survival ៀ% > 80% S . purpuratus 1 Pore Water % Normal Larval ៀ% > 80% Development Haliotis sp. 1 Subsurface % Normal Shell ៀ...C. gigas survival, R. abronius survival, S . purpuratus development , and P450 induction. Of 16 sur- vival tests with G. japonica, 10 showed effects...showed effects in S . purpuratus development , and one showed no effects. Effects were observed using R. abronius at four sites and no effects were

  4. Progression of methanogenic degradation of crude oil in the subsurface

    USGS Publications Warehouse

    Bekins, B.A.; Hostettler, F.D.; Herkelrath, W.N.; Delin, G.N.; Warren, E.; Essaid, H.I.

    2005-01-01

    Our results show that subsurface crude-oil degradation rates at a long-term research site were strongly influenced by small-scale variations in hydrologic conditions. The site is a shallow glacial outwash aquifer located near Bemidji in northern Minnesota that became contaminated when oil spilled from a broken pipeline in August 1979. In the study area, separate-phase oil forms a subsurface oil body extending from land surface to about 1 m (3.3 ft) below the 6-8-m (20-26 ft)-deep water table. Oil saturation in the sediments ranges from 10-20% in the vadose zone to 30-70% near the water table. At depths below 2 m (6.6 ft), degradation of the separate-phase crude oil occurs under methanogenic conditions. The sequence of methanogenic alkane degradation depletes the longer chain n-alkanes before the shorter chain n-alkanes, which is opposite to the better known aerobic sequence. The rates of degradation vary significantly with location in the subsurface. Oil-coated soils within 1.5 m (5 ft) of land surface have experienced little degradation where soil water saturation is less than 20%. Oil located 2-8 m (6.6-26 ft) below land surface in areas of higher recharge has been substantially degraded. The best explanation for the association between recharge and enhanced degradation seems to be increased downward transport of microbial growth nutrients to the oil body. This is supported by observations of greater microbial numbers at higher elevations in the oil body and significant decreases with depth in nutrient concentrations, especially phosphorus. Our results suggest that environmental effects may cause widely diverging degradation rates in the same spill, calling into question dating methods based on degradation state. Copyright ?? 2005. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  5. Geomicrobial Processes and Biodiversity in the Deep Terrestrial Subsurface

    SciTech Connect

    Fredrickson, Jim K.; Balkwill, David L.

    2005-09-01

    The concept of a deep microbial biosphere has advanced over the past several decades from a hypothesis viewed with considerable skepticism to being widely accepted. Phylogenetically diverse prokaryotes have been cultured from or detected via characterization of directly-extracted nucleic acids from a wide range of deep terrestrial environments. Recent advances have linked the metabolic potential of these microorganisms, determined directly or inferred from phylogeny, to biogeochemical reactions determined via geochemical measurements and modeling. Buried organic matter or kerogen is an important source of energy for sustaining anaerobic heterotrophic microbial communities in deep sediments and sedimentary rock although rates of respiration are among the slowest rates measured on the planet. In contrast, Subsurface Lithoautotrophic Microbial Ecosystems based on H2 as the primary energy source appear to dominate in many crystalline rock environments. These photosynthesis-independent ecosystems remain an enigma due to the difficulty in accessing and characterizing appropriate samples. Deep mines and dedicated rock laboratories, however, may offer unprecedented opportunities for investigating subsurface microbial communities and their interactions with the geosphere.

  6. Introduction: energy and the subsurface

    PubMed Central

    Viswanathan, Hari S.

    2016-01-01

    This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection. This article is part of the themed issue ‘Energy and the subsurface’. PMID:27597784

  7. Fluid-powered subsurface pump

    SciTech Connect

    Gipson, T.C.

    1991-12-03

    This paper describes a fluid-powered pump for attachment to small diametered coiled tubing for pumping subsurface liquid from a well production tube. It comprises: a pump housing having an upper end and a lower end, the upper end releasably attachable to a downhole end of the coiled tubing, the inside of the upper end of the housing in fluid communication with the inside of the coiled tubing; a cross head seal member dividing the pump into an upper chamber and a lower chamber, the upper chamber in fluid communication with the inside of the coiled tubing; a pump actuator extending between the upper and lower chambers, the actuator having an upper piston head sealingly fitted to reciprocate in the upper chamber and a lower piston head sealingly fitted to reciprocate in the lower chamber, the upper piston head and the lower piston head connected to each other by a connector rod sealing slidable in the cross head seal member, the actuator having a conduit for fluid communication between the upper chamber and the lower chamber, the conduit extending from an orifice in the top surface of the upper piston head, through the connector rod to a port above the top surface of the lower piston head.

  8. Subsurface Explosions in Granular Media

    NASA Astrophysics Data System (ADS)

    Lai, Shuyue; Houim, Ryan; Oran, Elaine

    2015-11-01

    Numerical simulations of coupled gas-granular flows are used to study properties of shock formation and propagation in media, such as sand or regolith on the moon, asteroids, or comets. The simulations were performed with a multidimensional fully compressible model, GRAF, which solves two sets of coupled Navier-Stokes equations, one for the gas and one for the granular medium. The specific case discussed here is for a subsurface explosion in a granular medium initiated by an equivalent of 200g of TNT in depths ranging from 0.1m to 3m. The background conditions of 100K, 10 Pa and loose initial particle volume fraction of 25% are consistent with an event on a comet. The initial blast creates a cavity as a granular shock expands outwards. Since the gas-phase shock propagates faster than the granular shock in loose, granular material, some gas and particles are ejected before the granular shock arrives. When the granular shock reaches the surface, a cap-like structure forms. This cap breaks and may fall back on the surface and in this process, relatively dense particle clusters form. At lower temperatures, the explosion timescales are increased and entrained particles are more densely packed.

  9. Foraminiferal radiocarbon record of northeast Pacific decadal subsurface variability

    NASA Astrophysics Data System (ADS)

    Roach, Lydia D.; Charles, Christopher D.; Field, David B.; Guilderson, Thomas P.

    2013-09-01

    The decadal dynamics of the subsurface North Pacific Ocean are largely inaccessible beyond sparse instrumental observations spanning the last 20 years. Here we present a ˜200 year long record of benthic foraminiferal radiocarbon (Δ14C), extracted at biennial resolution from the annually laminated sediments at the Santa Barbara Basin (SBB) depocenter (˜600 m). The close match between core top benthic foraminiferal Δ14C values and the Δ14C of seawater dissolved inorganic carbon (DIC) suggests that benthic foraminifera faithfully capture the bottom water radiocarbon concentrations, as opposed to that of the deeper (>0.5 cm) sediment porewater zone. The full time series of benthic foraminiferal Δ14C displays significant variability on decadal timescales, with excursions on the order of 40‰. These excursions are overprinted by a unidirectional trend over the late 20th century that likely reflects the sedimentary incorporation of bomb radiocarbon (via remineralized particulate organic carbon). We isolate this trend by means of a one-dimensional oxidation model, which considers the possible contribution of remineralized particles to the total ambient carbon pool. This oxidation model also considers the possible influence of carbon with a variety of sources (ages). Though variable oxidation of preaged carbon could exert a strong influence on benthic foraminiferal radiocarbon variability, the totality of evidence points to the vertical density structure along the Southern California Margin (SCM) as the primary driver of the SBB benthic foraminiferal Δ14C record. For example, intervals characterized by significantly lower Δ14C values correspond to periods of enhanced upwelling and subsurface equatorward flow along the SCM.

  10. Deglacial Subsurface Temperature Change in the Tropical North Atlantic Linked to Atlantic Meridional Overturning Circulation Variability

    NASA Astrophysics Data System (ADS)

    Schmidt, M. W.; Chang, P.; Otto-Bliesner, B. L.

    2010-12-01

    Coupled ocean-atmosphere modeling experiments indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly coupled to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes (Zhang, 2007; Chang et al., 2008; and Chiang et al., 2008). While a slowdown of AMOC in these experiments results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming due to rapid reorganizations of ocean circulation patterns (Wan et al., 2009). In addition, observational records of detrended 20th century ocean temperature and salinity variability show a strong anticorrelation between surface cooling and subsurface warming in the TNA over the past several decades, suggesting changing vertical temperature gradients in this region may be a distinct fingerprint of AMOC variability (Zhang 2007). In order to test the hypothesis that subsurface temperature change in the TNA is coupled to AMOC variability across abrupt climate events over the last deglacial, we reconstructed high-resolution Mg/Ca-temperature and δ18O records from both surface (G. ruber) and sub-thermocline dwelling (G. truncatulinoides, 350-500 m depth and G. crassaformis, 450-580 m) planktonic foraminifera in the southern Caribbean Sea sediment core VM12-107 (11.33oN, 66.63oW; 1079 m; 18 cm/kyr sedimentation rate). Sea surface temperatures indicate a gradual warming in the TNA starting at ~19 kyr BP with small cold reversals of ~1.5oC during Heinrich Event 1 (H1) and the Younger Dryas (YD). In contrast, last glacial maximum subsurface temperatures were as much as 2.5oC warmer than Late Holocene values and H1 and the YD are marked by the warmest subsurface temperatures characterized by abrupt temperature increases as large as 4-5oC. Furthermore, a comparison of our subsurface temperature record with the Bermuda Rise 231Pa/230Th proxy record of AMOC variability (McManus et al., 2004) indicates a strong

  11. Watershed-Scale Fungal Community Characterization along a pH Gradient in a Subsurface Environment Cocontaminated with Uranium and Nitrate

    PubMed Central

    Jasrotia, Puja; Green, Stefan J.; Canion, Andy; Overholt, Will A.; Prakash, Om; Wafula, Denis; Hubbard, Daniela; Watson, David B.; Schadt, Christopher W.; Brooks, Scott C.

    2014-01-01

    The objective of this study was to characterize fungal communities in a subsurface environment cocontaminated with uranium and nitrate at the watershed scale and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution, and diversity of fungi in subsurface groundwater samples were determined using quantitative and semiquantitative molecular techniques, including quantitative PCR of eukaryotic small-subunit rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from the subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH <4.5) conditions. Fungal isolates recovered from subsurface sediments, including cultures of the genus Coniochaeta, which were detected in abundance in pyrosequence libraries of site groundwater samples, were shown to reduce nitrate to nitrous oxide. Denitrifying fungal isolates recovered from the site were classified and found to be distributed broadly within the phylum Ascomycota and within a single genus of the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions. PMID:24389927

  12. Watershed-scale fungal community characterization along a pH gradient in a subsurface environment cocontaminated with uranium and nitrate.

    PubMed

    Jasrotia, Puja; Green, Stefan J; Canion, Andy; Overholt, Will A; Prakash, Om; Wafula, Denis; Hubbard, Daniela; Watson, David B; Schadt, Christopher W; Brooks, Scott C; Kostka, Joel E

    2014-03-01

    The objective of this study was to characterize fungal communities in a subsurface environment cocontaminated with uranium and nitrate at the watershed scale and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution, and diversity of fungi in subsurface groundwater samples were determined using quantitative and semiquantitative molecular techniques, including quantitative PCR of eukaryotic small-subunit rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from the subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH <4.5) conditions. Fungal isolates recovered from subsurface sediments, including cultures of the genus Coniochaeta, which were detected in abundance in pyrosequence libraries of site groundwater samples, were shown to reduce nitrate to nitrous oxide. Denitrifying fungal isolates recovered from the site were classified and found to be distributed broadly within the phylum Ascomycota and within a single genus of the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions.

  13. Watershed scale fungal community characterization along a pH gradient in a subsurface environment co-contaminated with uranium and nitrate

    SciTech Connect

    Jasrotia, Puja; Green, Stefan; Canion, Andy; Overholt, Will; Prakash, Om; Wafula, Dennis; Hubbard, Daniela; Watson, David B; Schadt, Christopher Warren; Brooks, Scott C; Kostka,

    2014-01-01

    The objective of this study was to characterize fungal communities in a subsurface environment co-contaminated with uranium and nitrate at the watershed scale, and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution and diversity of fungi in subsurface groundwater samples were determined using quantitative and semi-quantitative molecular techniques, including quantitative PCR of eukaryotic SSU rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH < 4.5) conditions. Fungal isolates recovered from subsurface sediments were shown to reduce nitrate to nitrous oxide, including cultures of the genus Coniochaeta that were detected in abundance in pyrosequence libraries of site groundwater samples. Denitrifying fungal isolates recovered from the site were classified, and found to be distributed broadly within the phylum Ascomycota, and within a single genus within the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions.

  14. STRUCTURE AND FUNCTION OF SUBSURFACE MICROBIAL COMMUNITIES AFFECTING RADIONUCLIDE TRANSPORT AND BIOIMMOBILIZATION

    SciTech Connect

    Joel E. Kostka; Lee Kerkhof; Kuk-Jeong Chin; Martin Keller; Joseph W. Stucki

    2011-06-15

    The objectives of this project were to: (1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), (2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and (3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee, where the subsurface is exposed to mixed contamination predominated by uranium and nitrate. A total of 20 publications (16 published or 'in press' and 4 in review), 10 invited talks, and 43 contributed seminars/ meeting presentations were completed during the past four years of the project. PI Kostka served on one proposal review panel each year for the U.S. DOE Office of Science during the four year project period. The PI leveraged funds from the state of Florida to purchase new instrumentation that aided the project. Support was also leveraged by the PI from the Joint Genome Institute in the form of two successful proposals for genome sequencing. Draft genomes are now available for two novel species isolated during our studies and 5 more genomes are in the pipeline. We effectively addressed each of the three project objectives and research highlights are provided. Task I - Isolation and characterization of novel anaerobes: (1) A wide range of pure cultures of metal-reducing bacteria, sulfate-reducing bacteria, and denitrifying bacteria (32 strains) were isolated from subsurface sediments of the Oak Ridge Field Research Center (ORFRC), where the subsurface is exposed to mixed contamination of uranium and nitrate. These isolates which are new

  15. Subsurface application enhances benefits of manure redistribution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic and environmental effects of different poultry litter application methods (surface vs. subsurface) and timings (fall ...

  16. Subsurface Imaging with the Scanning Microwave Microscope

    NASA Astrophysics Data System (ADS)

    Kopanski, Joseph; You, Lin; Michelson, Jonathan; Hitz, Emily; Obeng, Yaw; Back End of the Line Reliability; Metrology Project Team

    2015-03-01

    The scanning microwave microscope (SMM) forms images from the reflected amplitude and phase of an incident RF (~ 2.3 GHz) signal. The reflected signal is a function of the properties of the tip-sample contact, but can also be influenced by buried interfaces and subsurface variations of the sample permittivity. This mechanism allows limited imaging of conductors buried within dielectrics, voids within metal, or multiple metal layers with different permittivity. Subsurface SMM data acquisition modes include passive and various active data acquisition modes. The theory of sub-surface imaging with SMM and COMSOL multi-physics simulations of specific situations will be presented. Measurements of specifically designed test structures and correlation with simulations show the sensitivity and resolution of the technique applied to imaging subsurface metal lines embedded in dielectric. Applications include metrology for back end of the line (BEOL) multi-level metallization and three-dimensional integrated circuits (3D-ICs).

  17. SUBSURFACE REPOSITORY INTEGRATED CONTROL SYSTEM DESIGN

    SciTech Connect

    D.C. Randle

    2000-01-07

    The primary purpose of this document is to develop a preliminary high-level functional and physical control system architecture for the potential repository at Yucca Mountain. This document outlines an overall control system concept that encompasses and integrates the many diverse process and communication systems being developed for the subsurface repository design. This document presents integrated design concepts for monitoring and controlling the diverse set of subsurface operations. The Subsurface Repository Integrated Control System design will be composed of a series of diverse process systems and communication networks. The subsurface repository design contains many systems related to instrumentation and control (I&C) for both repository development and waste emplacement operations. These systems include waste emplacement, waste retrieval, ventilation, radiological and air monitoring, rail transportation, construction development, utility systems (electrical, lighting, water, compressed air, etc.), fire protection, backfill emplacement, and performance confirmation. Each of these systems involves some level of I&C and will typically be integrated over a data communications network throughout the subsurface facility. The subsurface I&C systems will also interface with multiple surface-based systems such as site operations, rail transportation, security and safeguards, and electrical/piped utilities. In addition to the I&C systems, the subsurface repository design also contains systems related to voice and video communications. The components for each of these systems will be distributed and linked over voice and video communication networks throughout the subsurface facility. The scope and primary objectives of this design analysis are to: (1) Identify preliminary system-level functions and interfaces (Section 6.2). (2) Examine the overall system complexity and determine how and on what levels the engineered process systems will be monitored, controlled, and

  18. Microbial life in the deep terrestrial subsurface

    SciTech Connect

    Fliermans, C.B.; Balkwill, D.L.; Beeman, R.E.

    1988-12-31

    The distribution and function of microorganisms is a vital issue in microbial ecology. The US Department of Energy`s Program, ``Microbiology of the Deep Subsurface,`` concentrates on establishing fundamental scientific information about organisms at depth, and the use of these organisms for remediation of contaminants in deep vadose zone and groundwater environments. This investigation effectively extends the Biosphere hundreds of meters into the Geosphere and has implications to a variety of subsurface activities.

  19. Floating insulated conductors for heating subsurface formations

    DOEpatents

    Burns, David; Goodwin, Charles R.

    2014-07-29

    A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

  20. Transport of Gas and Solutes in Permeable Estuarine Sediments

    DTIC Science & Technology

    2008-01-01

    subsurface methane accumulations that formed gas layers up to 2 cm thick at 3 to 10 cm sediment depth. This gas was collected in the chambers and the...reactive solutes in the surface layers of the bed. Gas producing organisms benefit from this filtration, i.e. methanogens from the filtration of organic

  1. Exploring Microbial Life in Oxic Sediments Underlying Oligotrophic Ocean Gyres

    NASA Astrophysics Data System (ADS)

    Ziebis, W.; Orcutt, B.; Wankel, S. D.; D'Hondt, S.; Szubin, R.; Kim, J. N.; Zengler, K.

    2015-12-01

    Oxygen, carbon and nutrient availability are defining parameters for microbial life. In contrast to organic-rich sediments of the continental margins, where high respiration rates lead to a depletion of O2 within a thin layer at the sediment surface, it was discovered that O2 penetrates several tens of meters into organic-poor sediments underlying oligotrophic ocean gyres. In addition, nitrate, another important oxidant, which usually disappears rapidly with depth in anoxic sediments, tends to accumulate above seawater concentrations in the oxic subsurface, reflecting the importance of nitrogen cycling processes, including both nitrification and denitrification. Two IODP drilling expeditions were vital for exploring the nature of the deep subsurface beneath oligotrophic ocean gyres, expedition 329 to the South Pacific Gyre (SPG) and expedition 336 to North Pond, located on the western flank of the Mid-Atlantic ridge beneath the North Atlantic Gyre. Within the ultra-oligotrophic SPG O2 penetrates the entire sediment column from the sediment-water interface to the underlying basement to depths of > 75 m. At North Pond, a topographic depression filled with sediment and surrounded by steep basaltic outcrops, O2 penetrates deeply into the sediment (~ 30 m) until it eventually becomes depleted. O2 also diffuses upward into the sediment from seawater circulating within the young crust underlying the sediment, resulting in a deep oxic layer several meters above the basalt. Despite low organic carbon contents microbial cells persist throughout the entire sediment column within the SPG (> 75 m) and at North Pond, albeit at low abundances. We explored the nature of the subsurface microbial communities by extracting intact cells from large volumes of sediment obtained from drill cores of the two expeditions. By using CARD-FiSH, amplicon (16s rRNA) and metagenome sequencing we shed light on the phylogenetic and functional diversity of the elusive communities residing in the

  2. Microbial community transitions across the deep sediment-basement interface

    NASA Astrophysics Data System (ADS)

    Labonté, J.; Lever, M. A.; Orcutt, B.

    2015-12-01

    Previous studies of microbial abundance and geochemistry in deep marine sediments indicate a stimulation of microbial activity near the sediment-basement interface; yet, the extent to which microbial communities in bottom sediments and underlying crustal habitats interact is unclear. We conducted tag pyrosequencing on DNA extracted from a spectrum of deep sediment-basement samples to try to identify patterns in microbial community shifts across sediment-basement interfaces, focusing on samples from the subsurface of the Juan de Fuca Ridge flank (IODP Expedition 327). Our results demonstrate that sediment and the basaltic crust harbor microbial communities that are phylogenetically connected, but the eveness is characteristic of the environment. We will discuss the microbial community transitions that occur horizontally along fluid flow pathways and vertically across the sediment basement interface, as well as the possible implications regarding the controls of microbial community composition along deep sediment-basement interfaces in hydrothermal systems. We will also highlight efforts to overcome sample contamination in crustal subsurface samples.

  3. In-Well Sediment Incubators to Evaluate Microbial Community Stability and Dynamics following Bioimmobilization of Uranium

    SciTech Connect

    Baldwin, Brett R.; Peacock, Aaron D.; Gan, M.; Resch, Charles T.; Arntzen, Evan V.; Smithgall, A. N.; Pfiffner, S.; Freifeld, Barry M.; White, D. C.; Long, Philip E.

    2009-09-23

    An in-situ incubation device (ISI) was developed in order to investigate the stability and dynamics of sediment associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Here we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During the 7 month deployment oxidized Rifle aquifer background sediments (RABS) were deployed in previously biostimulated wells under iron reducing conditions, cell densities of known iron reducing bacteria including Geobacteraceae increased significantly showing the microbial community response to local subsurface conditions. PLFA profiles of RABS following in situ deployment were strikingly similar to those of adjacent sediment cores suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployed reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISIs to monitor microbial community stability and response to subsurface conditions.

  4. Energy Requirements of Hydrogen-utilizing Microbes: A Boundary Condition for Subsurface Life

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Alperin, Marc J.; Albert, Daniel B.; Martens, Christopher S.

    2003-01-01

    Microbial ecosystems based on the energy supplied by water-rock chemistry carry particular significance in the context of geo- and astrobiology. With no direct dependence on solar energy, lithotrophic microbes could conceivably penetrate a planetary crust to a depth limited only by temperature or pressure constraints (several kilometers or more). The deep lithospheric habitat is thereby potentially much greater in volume than its surface counterpart, and in addition offers a stable refuge against inhospitable surface conditions related to climatic or atmospheric evolution (e.g., Mars) or even high-energy impacts (e.g., early in Earth's history). The possibilities for a deep microbial biosphere are, however, greatly constrained by life s need to obtain energy at a certain minimum rate (the maintenance energy requirement) and of a certain minimum magnitude (the energy quantum requirement). The mere existence of these requirements implies that a significant fraction of the chemical free energy available in the subsurface environment cannot be exploited by life. Similar limits may also apply to the usefulness of light energy at very low intensities or long wavelengths. Quantification of these minimum energy requirements in terrestrial microbial ecosystems will help to establish a criterion of energetic habitability that can significantly constrain the prospects for life in Earth's subsurface, or on other bodies in the solar system. Our early work has focused on quantifying the biological energy quantum requirement for methanogenic archaea, as representatives of a plausible subsurface metabolism, in anoxic sediments (where energy availability is among the most limiting factors in microbial population growth). In both field and laboratory experiments utilizing these sediments, methanogens retain a remarkably consistent free energy intake, in the face of fluctuating environmental conditions that affect energy availability. The energy yields apparently required by

  5. SORPTION OF NONIONIC SURFACTANT OLIGOMERS TO SEDIMENT AND PCE DNAPL: EFFECTS ON PCE DISTRIBUTION BETWEEN WATER AND SEDIMENT. (R826650)

    EPA Science Inventory

    Introduction of surfactant mixtures to the subsurface for the purpose of
    surfactant-enhanced aquifer remediation requires consideration of the effects of
    surfactant sorption to sediment and nonaqueous phase liquids. These effects
    include alteration of the solubiliz...

  6. Subsurface structure around Omi basin using borehole database

    NASA Astrophysics Data System (ADS)

    Kitada, N.; Ito, H.; Takemura, K.; Mitamura, M.

    2015-12-01

    Kansai Geo-informatics Network (KG-NET) is organized as a new system of management of GI-base in 2005. This organization collects the geotechnical and geological information of borehole data more than 60,000 data. GI-base is the database system of the KG-NET and platform to use these borehole data. Kansai Geo-informatics Research Committee (KG-R) is tried to explain the geotechnical properties and geological environment using borehole database in Kansai area. In 2014, KG-R established the 'Shin-Kansai Jiban Omi plain', and explain the subsurface geology and characteristics of geotechnical properties. In this study we introduce this result and consider the sedimental environment and characteristics in this area. Omi Basin is located in the central part of Shiga Prefecture which includes the largest lake in Japan called Lake Biwa. About 15,000 borehole data are corrected to consider the subsurface properties. The outline of topographical and geological characteristics of the basin is divided into west side and east side. The west side area is typical reverse fault called Biwako-Seigan fault zone along the lakefront. From Biwako-Seigan fault, the Omi basin is tilting down from east to west. Otherwise, the east areas distribute lowland and hilly area comparatively. The sedimentary facies are also complicate and difficult to be generally evaluated. So the discussion has been focused about mainly the eastern and western part of Lake Biwa. The widely dispersed volcanic ash named Aira-Tn (AT) deposited before 26,000-29,000 years ago (Machida and Arai, 2003), is sometimes interbedded the humic layers in the low level ground area. However, because most of the sediments are comprised by thick sand and gravels whose deposit age could not be investigated, it is difficult to widely identify the boundary of strata. Three types of basement rocks are distributed mainly (granite, sediment rock, rhyolite), and characteristics of deposit are difference of each backland basement rock

  7. Tillage impact on herbicide loss by surface runoff and lateral subsurface flow.

    PubMed

    Potter, Thomas L; Bosch, David D; Strickland, Timothy C

    2015-10-15

    There is worldwide interest in conservation tillage practices because they can reduce surface runoff, and agrichemical and sediment losses from farm fields. Since these practices typically increase infiltration, their use may increase subsurface transport of water-soluble contaminants. Thus, to assess long-term environmental benefits of conservation tillage data may be needed that quantify both surface and subsurface contaminant fluxes. This study focused on the herbicide fluometuron (N,N-dimethyl-N'-[3-(trifluoromethyl)phenyl]-urea) and its soil degradate DMF (N-methyl-N'-[3-(trifluoromethyl) phenyl]-urea). Both compounds are classed as "leachable". They were measured for 10 years in surface runoff and lateral subsurface flow from paired fields located on a hill slope in the Atlantic Coastal Plain region of the southeastern USA. One group of fields was conventionally tilled incorporating all crop residues into soil prior to planting. The second was strip tilled, a common conservation tillage practice. Seven fluometuron applications were made to cotton (Gossypium hirsutum) produced in rotation with peanut (Arachis hypogea). Combined fluometuron and DMF surface and subsurface losses from the conventionally tilled fields were equivalent to 1.2% and 0.13% of fluometuron applied and 0.31% and 0.32% from the strip tilled fields. Annual surface runoff losses were significantly greater from the conventionally tilled fields while the strip tilled fields had significantly greater annual subsurface losses. Results demonstrated that shifting from conventional to conservation tillage management of farm fields in this landscape will reduce surface runoff losses of herbicides like fluometuron but subsurface losses will likely increase. The same trends can be expected in landscapes with similar soil and hydrologic properties. This should be considered when planning implementation of programs that promote conservation tillage use.

  8. Analysis of the Impact of Subsurface Contaminant Plumes on Stream Water Quality Under Natural and Managed Conditions

    NASA Astrophysics Data System (ADS)

    Keizer, J. P.; Sudicky, E. A.

    2001-12-01

    The Integrated Hydrology Model (InHM) is a fully-integrated 3D control-volume finite element model which can simulate water flow and solute transport on the two-dimensional land surface and in the three-dimensional dual-continua subsurface under variably-saturated conditions. Full coupling of the surface and subsurface flow regimes is accomplished by simultaneously solving one system of nonlinear discrete equations for overland flow rates and water depths, stream flow rates, subsurface pressure heads, saturations and velocities, as well as water fluxes between continua. The numerical solution of the coupled advection-dispersion equations describing solute transport in the surface and subsurface flow domains is achieved in an analogous manner. High-resolution 3D numerical experiments performed with the model evaluate the downstream surface-water and stream-bottom sediment quality arising from a subsurface solute plume discharging into a stream under natural conditions. These simulations are compared with cases where the plume is intercepted by pumping wells near point of discharge. Comparisons are made for low (baseflow) and high (precipitation-event driven) stream flow rates for each case. A sensitivity analysis involving different surface-subsurface and transport parameters and plume capture scenarios will also be presented.

  9. Sediment Toxicity Testing

    EPA Science Inventory

    Sediment toxicity testing has become a fundamental component of regulatory frameworks for assessing the risks posed by contaminated sediments and for development of chemical sediment quality guidelines. Over the past two decades, sediment toxicity testing methods have advanced co...

  10. Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting

    NASA Astrophysics Data System (ADS)

    Foucher, Anthony; Laceby, Patrick J.; Salvador-Blanes, Sébastien; Evrard, Olivier; Le Gall, Marion; Lefèvre, Irène; Cerdan, Olivier; Rajkumar, Vignesh; Desmet, Marc

    2015-12-01

    Soil erosion is one of the main factors influencing land degradation and water quality at the global scale. Identifying the main sediment sources is therefore essential for the implementation of appropriate soil erosion mitigation measures. Accordingly, caesium-137 (137Cs) concentrations were used to determine the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. A distribution modelling approach was used to quantify the relative sediment contributions from surface and subsurface sources. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of

  11. Biogeochemical Cycle of Methanol in Anoxic Deep-Sea Sediments.

    PubMed

    Yanagawa, Katsunori; Tani, Atsushi; Yamamoto, Naoya; Hachikubo, Akihiro; Kano, Akihiro; Matsumoto, Ryo; Suzuki, Yohey

    2016-06-25

    The biological flux and lifetime of methanol in anoxic marine sediments are largely unknown. We herein reported, for the first time, quantitative methanol removal rates in subsurface sediments. Anaerobic incubation experiments with radiotracers showed high rates of microbial methanol consumption. Notably, methanol oxidation to CO2 surpassed methanol assimilation and methanogenesis from CO2/H2 and methanol. Nevertheless, a significant decrease in methanol was not observed after the incubation, and this was attributed to the microbial production of methanol in parallel with its consumption. These results suggest that microbial reactions play an important role in the sources and sinks of methanol in subseafloor sediments.

  12. Wave-Based Subsurface Guide Star

    SciTech Connect

    Lehman, S K

    2011-07-26

    Astronomical or optical guide stars are either natural or artificial point sources located above the Earth's atmosphere. When imaged from ground-based telescopes, they are distorted by atmospheric effects. Knowing the guide star is a point source, the atmospheric distortions may be estimated and, deconvolved or mitigated in subsequent imagery. Extending the guide star concept to wave-based measurement systems to include acoustic, seismo-acoustic, ultrasonic, and radar, a strong artificial scatterer (either acoustic or electromagnetic) may be buried or inserted, or a pre-existing or natural sub-surface point scatterer may be identified, imaged, and used as a guide star to determine properties of the sub-surface volume. That is, a data collection is performed on the guide star and the sub-surface environment reconstructed or imaged using an optimizer assuming the guide star is a point scatterer. The optimization parameters are the transceiver height and bulk sub-surface background refractive index. Once identified, the refractive index may be used in subsequent reconstructions of sub-surface measurements. The wave-base guide star description presented in this document is for a multimonostatic ground penetrating radar (GPR) but is applicable to acoustic, seismo-acoustic, and ultrasonic measurement systems operating in multimonostatic, multistatic, multibistatic, etc., modes.

  13. Subsurface Nitrogen-Cycling Microbial Communities at Uranium Contaminated Sites in the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Cardarelli, E.; Bargar, J.; Williams, K. H.; Dam, W. L.; Francis, C.

    2015-12-01

    Throughout the Colorado River Basin (CRB), uranium (U) persists as a relic contaminant of former ore processing activities. Elevated solid-phase U levels exist in fine-grained, naturally-reduced zone (NRZ) sediments intermittently found within the subsurface floodplain alluvium of the following Department of Energy-Legacy Management sites: Rifle, CO; Naturita, CO; and Grand Junction, CO. Coupled with groundwater fluctuations that alter the subsurface redox conditions, previous evidence from Rifle, CO suggests this resupply of U may be controlled by microbially-produced nitrite and nitrate. Nitrification, the two-step process of archaeal and bacterial ammonia-oxidation followed by bacterial nitrite oxidation, generates nitrate under oxic conditions. Our hypothesis is that when elevated groundwater levels recede and the subsurface system becomes anoxic, the nitrate diffuses into the reduced interiors of the NRZ and stimulates denitrification, the stepwise anaerobic reduction of nitrate/nitrite to dinitrogen gas. Denitrification may then be coupled to the oxidation of sediment-bound U(IV) forming mobile U(VI), allowing it to resupply U into local groundwater supplies. A key step in substantiating this hypothesis is to demonstrate the presence of nitrogen-cycling organisms in U-contaminated, NRZ sediments from the upper CRB. Here we investigate how the diversity and abundances of nitrifying and denitrifying microbial populations change throughout the NRZs of the subsurface by using functional gene markers for ammonia-oxidation (amoA, encoding the α-subunit of ammonia monooxygenase) and denitrification (nirK, nirS, encoding nitrite reductase). Microbial diversity has been assessed via clone libraries, while abundances have been determined through quantitative polymerase chain reaction (qPCR), elucidating how relative numbers of nitrifiers (amoA) and denitrifiers (nirK, nirS) vary with depth, vary with location, and relate to uranium release within NRZs in sediment

  14. Subsurface controls on historical subsidence rates and associated wetland loss in southcentral Louisiana

    USGS Publications Warehouse

    Morton, Robert A.; Buster, Noreen A.; Krohn, M. Dennis

    2002-01-01

    Two regional releveling profiles and six tide gauges provide a basis for evaluating recent rates of delta plain subsidence in southcentral Louisiana. Analyses of these records demonstrate close correlations among highest historical rates of subsidence, rapid wetland losses, large volume hydrocarbon production, and probable reactivation of deep subsurface faults. Other researchers have demonstrated that the highest geological subsidence rates of the Mississippi delta plain (<3 mm/yr) correspond closely to the thickest Holocene sediments that fill the underlying incised valley. Within that geologic framework, highest historical subsidence rates (as much as 23 mm/yr) correspond to surface projections of the reactivated Lake Hatch and Golden Meadow fault zones and to individual oil and gas fields. The initial acceleration and subsequent decline in rates of wetland loss in southcentral Louisiana are attributed partly to increased and then possibly decreased rates of subsidence that were related to increased and then decreased rates of fluid production. Decreases in subsurface pore pressures associated with gas production were so large that the state of stress was altered and critically stressed faults were likely reactivated. Subsidence rates in coastal Louisiana associated with natural compaction and dewatering of Holocene deltaic sediments should decrease with time. Therefore historical rates of delta plain subsidence that accelerate and typically exceed geological subsidence rates are most likely influenced by anthropogenic activities, such as subsurface fluid extraction.

  15. Finding Signals for Quiescence from the Dark Matter in Marine Subsurface Metagenomics

    NASA Astrophysics Data System (ADS)

    Biddle, J.; Marsh, A.; Rambo, I. M.; Pasqualone, A.; Christman, G.

    2014-12-01

    Microorganisms are expected to occupy deep marine sediments and underlying basalts, suriving on limited energy and potentially dividing on a thousand year time scale. For a microorganism to do this, and be only slightly active, is a difficult process to maintain, as many cells are programmed to be constantly active or face death. In order to maintain low levels of activity, cells may need additional control on which genes are activated in their genomes. In the surface world, particularly in eukaryotes, gene activity is controlled by factors including methylation of genes to silence activity. Methylation is now recognized as being present in many bacterial and archaeal genomes, and we hypothesized that this may be a prevalent lifestyle in subsurface organisms. We saw initial signals of methylation activity in a deep subsurface metatranscriptome and have shown which genes are methylated in a shallower sediment core. Methylation does appear to be a widespread phenomenon in microbial genomes of the subsurface, and additional tests will be needed to prove it's overall control on the potential for microbial activity.

  16. Effect of subsurface electrical heating and steam injection on the indigenous microbial community

    SciTech Connect

    Krauter, P.; MacQueen, D.; Horn, J.; Bishop, D.

    1995-11-01

    Since the potential for contaminant bioremediation in steam treated subsurface environments has not been explored, the thermal remedial treatment of a gasoline spill at Lawrence Livermore National Laboratory`s (LLNL) Livermore site provided an opportunity to study microbial community changes in the subsurface environment. Many terrestrial microorganisms die or become metabolically inactive if heated for a sufficient time at temperatures of 62-100{degrees}C thus thermal remediation techniques are expected to significantly alter the microbial community structure. We studied changes in community structure and population abundance as well as the characteristics of indigenous heat-tolerant microorganisms before and after steam treatment. Using fatty acid profiles from culturable microorganisms obtained from sediment cores before and after thermal treatment, a 90-98% decline in total microorganism populations in hot subsurface sediments (up to 94{degrees}C) was found. Surviving heat-tolerant microorganisms were found to possess elevated concentrations of saturated fatty acids in their lipid membranes. We also observed that some heat-tolerant microorganisms were capable of degrading gasoline compounds.

  17. Extraordinary phylogenetic diversity and metabolic versatility in aquifer sediment.

    PubMed

    Castelle, Cindy J; Hug, Laura A; Wrighton, Kelly C; Thomas, Brian C; Williams, Kenneth H; Wu, Dongying; Tringe, Susannah G; Singer, Steven W; Eisen, Jonathan A; Banfield, Jillian F

    2013-01-01

    Microorganisms in the subsurface represent a substantial but poorly understood component of the Earth's biosphere. Subsurface environments are complex and difficult to characterize; thus, their microbiota have remained as a 'dark matter' of the carbon and other biogeochemical cycles. Here we deeply sequence two sediment-hosted microbial communities from an aquifer adjacent to the Colorado River, CO, USA. No single organism represents more than ~1% of either community. Remarkably, many bacteria and archaea in these communities are novel at the phylum level or belong to phyla lacking a sequenced representative. The dominant organism in deeper sediment, RBG-1, is a member of a new phylum. On the basis of its reconstructed complete genome, RBG-1 is metabolically versatile. Its wide respiration-based repertoire may enable it to respond to the fluctuating redox environment close to the water table. We document extraordinary microbial novelty and the importance of previously unknown lineages in sediment biogeochemical transformations.

  18. Impact of abrupt deglacial climate change on tropical Atlantic subsurface temperatures.

    PubMed

    Schmidt, Matthew W; Chang, Ping; Hertzberg, Jennifer E; Them, Theodore R; Ji, Link; J, Link; Otto-Bliesner, Bette L

    2012-09-04

    Both instrumental data analyses and coupled ocean-atmosphere models indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly linked to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes. Although a slowdown of AMOC results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming because of rapid reorganizations of ocean circulation patterns at intermediate water depths. Here, we reconstruct high-resolution temperature records using oxygen isotope values and Mg/Ca ratios in both surface- and subthermocline-dwelling planktonic foraminifera from a sediment core located in the TNA over the last 22 ky. Our results show significant changes in the vertical thermal gradient of the upper water column, with the warmest subsurface temperatures of the last deglacial transition corresponding to the onset of the Younger Dryas. Furthermore, we present new analyses of a climate model simulation forced with freshwater discharge into the North Atlantic under Last Glacial Maximum forcings and boundary conditions that reveal a maximum subsurface warming in the vicinity of the core site and a vertical thermal gradient change at the onset of AMOC weakening, consistent with the reconstructed record. Together, our proxy reconstructions and modeling results provide convincing evidence for a subsurface oceanic teleconnection linking high-latitude North Atlantic climate to the tropical Atlantic during periods of reduced AMOC across the last deglacial transition.

  19. Impact of abrupt deglacial climate change on tropical Atlantic subsurface temperatures

    PubMed Central

    Schmidt, Matthew W.; Chang, Ping; Hertzberg, Jennifer E.; Them, Theodore R.; Ji, Link; Otto-Bliesner, Bette L.

    2012-01-01

    Both instrumental data analyses and coupled ocean-atmosphere models indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly linked to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes. Although a slowdown of AMOC results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming because of rapid reorganizations of ocean circulation patterns at intermediate water depths. Here, we reconstruct high-resolution temperature records using oxygen isotope values and Mg/Ca ratios in both surface- and subthermocline-dwelling planktonic foraminifera from a sediment core located in the TNA over the last 22 ky. Our results show significant changes in the vertical thermal gradient of the upper water column, with the warmest subsurface temperatures of the last deglacial transition corresponding to the onset of the Younger Dryas. Furthermore, we present new analyses of a climate model simulation forced with freshwater discharge into the North Atlantic under Last Glacial Maximum forcings and boundary conditions that reveal a maximum subsurface warming in the vicinity of the core site and a vertical thermal gradient change at the onset of AMOC weakening, consistent with the reconstructed record. Together, our proxy reconstructions and modeling results provide convincing evidence for a subsurface oceanic teleconnection linking high-latitude North Atlantic climate to the tropical Atlantic during periods of reduced AMOC across the last deglacial transition. PMID:22908256

  20. Anthropogenic effects on subsurface temperature in Bangkok

    NASA Astrophysics Data System (ADS)

    Taniguchi, M.

    2006-09-01

    Subsurface temperatures in Bangkok, where population and density increase rapidly, were analyzed to evaluate the effects of surface warming due to urbanization. The magnitude of surface warming evaluated from subsurface temperature in Bangkok was 1.7°C which agreed with meteorological data during the last 50 years. The depth apart from steady thermal gradient, which shows an indicator of the magnitude of surface warming due to additional heat from urbanization, was deeper at the center of the city than in the suburb areas of Bangkok. In order to separate surface warming effects into global warming effect and urbanization effect, analyses of subsurface temperature have been done depending on the distance from the city center. The results show that the expansion of urbanization in Bangkok reaches up to 80 km from the city center.

  1. Autonomous microexplosives subsurface tracing system final report.

    SciTech Connect

    Engler, Bruce Phillip; Nogan, John; Melof, Brian Matthew; Uhl, James Eugene; Dulleck, George R., Jr.; Ingram, Brian V.; Grubelich, Mark Charles; Rivas, Raul R.; Cooper, Paul W.; Warpinski, Norman Raymond; Kravitz, Stanley H.

    2004-04-01

    The objective of the autonomous micro-explosive subsurface tracing system is to image the location and geometry of hydraulically induced fractures in subsurface petroleum reservoirs. This system is based on the insertion of a swarm of autonomous micro-explosive packages during the fracturing process, with subsequent triggering of the energetic material to create an array of micro-seismic sources that can be detected and analyzed using existing seismic receiver arrays and analysis software. The project included investigations of energetic mixtures, triggering systems, package size and shape, and seismic output. Given the current absence of any technology capable of such high resolution mapping of subsurface structures, this technology has the potential for major impact on petroleum industry, which spends approximately $1 billion dollar per year on hydraulic fracturing operations in the United States alone.

  2. Urban heat island in the subsurface

    NASA Astrophysics Data System (ADS)

    Ferguson, Grant; Woodbury, Allan D.

    2007-12-01

    The urban heat island effect has received significant attention in recent years due to the possible effect on long-term meteorological records. Recent studies of this phenomenon have suggested that this may not be important to estimates of regional climate change once data are properly corrected. However, surface air temperatures within urban environments have significant variation, making correction difficult. In the current study, we examine subsurface temperatures in an urban environment and the surrounding rural area to help characterize the nature of this variability. The results of our study indicate that subsurface temperatures are linked to land-use and supports previous work indicating that the urban heat island effect has significant and complex spatial variability. In most situations, the relationship between subsurface and surface processes cannot be easily determined, indicating that previous studies that relying on such a linkage may require further examination.

  3. Subsurface Contaminants Focus Area annual report 1997

    SciTech Connect

    1997-12-31

    In support of its vision for technological excellence, the Subsurface Contaminants Focus Area (SCFA) has identified three strategic goals. The three goals of the SCFA are: Contain and/or stabilize contamination sources that pose an imminent threat to surface and ground waters; Delineate DNAPL contamination in the subsurface and remediate DNAPL-contaminated soils and ground water; and Remove a full range of metal and radionuclide contamination in soils and ground water. To meet the challenges of remediating subsurface contaminants in soils and ground water, SCFA funded more than 40 technologies in fiscal year 1997. These technologies are grouped according to the following product lines: Dense Nonaqueous-Phase Liquids; Metals and Radionuclides; Source Term Containment; and Source Term Remediation. This report briefly describes the SCFA 1997 technologies and showcases a few key technologies in each product line.

  4. Heterotrophic potential of Atribacteria from deep marine Antarctic sediment

    NASA Astrophysics Data System (ADS)

    Carr, S. A.; Orcutt, B.; Mandernack, K. W.; Spear, J. R.

    2015-12-01

    Bacteria belonging to the newly classified candidate phylum "Atribacteria" (formerly referred to as "OP9" and "JS1") are common in anoxic methane-rich sediments. However, the metabolic functions and biogeochemical role of these microorganisms in the subsurface remains unrealized due to the lack of pure culture representatives. This study observed a steady increase of Atribacteria-related sequences with increasing sediment depth throughout the methane-rich zone of the Adélie Basin, Antarctica (according to a 16S rRNA gene survey). To explore the functional potential of Atribacteria in this basin, samples from various depths (14, 25 and 97 meters below seafloor), were subjected to metagenomic sequencing. Additionally, individual cells were separated from frozen, unpreserved sediment for whole genome amplification. The successful isolation and sequencing of a single-amplified Atribacteria genome from these unpreserved sediments demonstrates a future use of single cell techniques with previously collected and frozen sediments. Our resulting single-cell amplified genome, combined with metagenomic interpretations, provides our first insights to the functional potential of Atribacteria in deep subsurface settings. As observed for non-marine Atribacteria, genomic analyses suggest a heterotrophic metabolism, with Atribacteria potentially producing fermentation products such as acetate, ethanol and CO2. These products may in turn support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacteria in anoxic methane-rich sediments.

  5. Using Geochemical Indicators to Distinguish High Biogeochemical Activity in Sediments

    NASA Astrophysics Data System (ADS)

    Kenwell, A. M.; Navarre-Sitchler, A.; Prugue, R.; Spear, J. R.; Williams, K. H.; Maxwell, R. M.

    2014-12-01

    A better understanding of how microbial communities interact with their surroundings in physically and chemically heterogeneous subsurface environments will lead to improved quantification of biogeochemical reactions and associated nutrient cycling. This study develops a methodology to predict elevated rates of biogeochemical activity (microbial "hotspots") in subsurface environments by correlating microbial community structure with the spatial distribution of geochemical indicators in subsurface sediments. Statistical hierarchical cluster analyses (HCA) of X-ray fluorescence (XRF), simulated precipitation leachate, bioavailable Fe and Mn, total organic carbon (TOC), microbial community structure, grain size, bulk density and moisture content data were used to identify regions of the subsurface characterized by biogeochemical hotspots and sample characteristics indicative of these hotspots within fluvially-derived aquifer sediments. The methodology has been applied to (a) alluvial materials collected at a former uranium mill site near Rifle, Colorado and (b) relatively undisturbed floodplain deposits (soils and sediments) collected along the East River near Crested Butte, Colorado. At Rifle, 33 sediment samples were taken from 8 sediment cores and at the East River 33 soil/sediment samples were collected across and perpendicular to 3 active meanders. The East River watershed exhibits characteristic fluvial progression and serves as a representative example of many headwater catchments with the upper Colorado River basin. Initial clustering revealed that operationally defined hotspots were characterized by high organic carbon, bioavailable iron and dark colors but not necessarily low hydraulic conductivity. Applying the method to identify hotspots in both contaminated and natural floodplain deposits and their associated alluvial aquifers demonstrates the broad applicability of a geochemical indicator based approach.

  6. MSTS - Multiphase Subsurface Transport Simulator theory manual

    SciTech Connect

    White, M.D.; Nichols, W.E.

    1993-05-01

    The US Department of Energy, through the Yucca Mountain Site Characterization Project Office, has designated the Yucca Mountain site in Nevada for detailed study as the candidate US geologic repository for spent nuclear fuel and high-level radioactive waste. Site characterization will determine the suitability of the Yucca Mountain site for the potential waste repository. If the site is determined suitable, subsequent studies and characterization will be conducted to obtain authorization from the Nuclear Regulatory Commission to construct the potential waste repository. A principal component of the characterization and licensing processes involves numerically predicting the thermal and hydrologic response of the subsurface environment of the Yucca Mountain site to the potential repository over a 10,000-year period. The thermal and hydrologic response of the subsurface environment to the repository is anticipated to include complex processes of countercurrent vapor and liquid migration, multiple-phase heat transfer, multiple-phase transport, and geochemical reactions. Numerical simulators based on mathematical descriptions of these subsurface phenomena are required to make numerical predictions of the thermal and hydrologic response of the Yucca Mountain subsurface environment The engineering simulator called the Multiphase Subsurface Transport Simulator (MSTS) was developed at the request of the Yucca Mountain Site Characterization Project Office to produce numerical predictions of subsurface flow and transport phenomena at the potential Yucca Mountain site. This document delineates the design architecture and describes the specific computational algorithms that compose MSTS. Details for using MSTS and sample problems are given in the {open_quotes}User`s Guide and Reference{close_quotes} companion document.

  7. Improving the biodegradative capacity of subsurface bacteria

    SciTech Connect

    Romine, M.F.; Brockman, F.J.

    1993-04-01

    The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates.

  8. Transcriptional profiling of human monocytes identifies the inhibitory receptor CD300a as regulator of transendothelial migration.

    PubMed

    Ghavampour, Sharang; Lange, Carsten; Bottino, Cristina; Gerke, Volker

    2013-01-01

    Local inflammatory responses are characterized by the recruitment of circulating leukocytes from the blood to sites of inflammation, a process requiring the directed migration of leukocytes across the vessel wall and hence a penetration of the endothelial lining. To identify underlying signalling events and novel factors involved in these processes we screened for genes differentially expressed in human monocytes following their adhesion to and passage through an endothelial monolayer. Functional annotation clustering of the genes identified revealed an overrepresentation of those associated with inflammation/immune response, in particular early monocyte to macrophage differentiation. Among the gene products so far not implicated in monocyte transendothelial migration was the inhibitory immune receptor CD300a. CD300a mRNA and protein levels were upregulated following transmigration and engagement of the receptor by anti-CD300a antibodies markedly reduced monocyte transendothelial migration. In contrast, siRNA mediated downregulation of CD300a in human monocytes increased their rate of migration. CD300a colocalized and cosedimented with actin filaments and, when activated, caused F-actin cytoskeleton alterations. Thus, monocyte transendothelial migration is accompanied by an elevation of CD300a which serves an inhibitory function possibly required for termination of the actual transmigration.

  9. Induction heaters used to heat subsurface formations

    DOEpatents

    Nguyen, Scott Vinh [Houston, TX; Bass, Ronald M [Houston, TX

    2012-04-24

    A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300.degree. C.

  10. Apparatus for passive removal of subsurface contaminants

    DOEpatents

    Pemberton, Bradley E.; May, Christopher P.; Rossabi, Joseph

    1997-01-01

    An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere.

  11. Radar Soundings of the Subsurface of Mars

    NASA Technical Reports Server (NTRS)

    Picardi, Giovanni; Plaut, Jeffrey J.; Biccari, Daniela; Bombaci, Ornella; Calabrese, Diego; Cartacci, Marco; Cicchetti, Andrea; Clifford, Stephen M.; Edenhofer, Peter; Farrell, William M.; Federico, Costanzo; Frigeri, Alessandro; Gurnett, Donald A.; Hagfors, Tor; Heggy, Essam; Herique, Alain; Huff, Richard L.; Ivanov, Anton B.; Johnson, William T. K.; Jordan, Rolando L.; Kirchner, Donald L.; Kofman, Wlodek; Leuschen, Carlton J.; Nielsen, Erling; Orosei, Roberto

    2005-01-01

    The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.

  12. Subsurface Microbes Expanding the Tree of Life

    SciTech Connect

    Banfield, Jillian

    2015-05-11

    Jillian Banfield, Ph.D., UC Berkeley Professor and Berkeley Lab Earth Sciences Division staff scientist and long-time user of the DOE Joint Genome Institute’s resources shares her perspective on how the DOE JGI helps advance her research addressing knowledge gaps related to the roles of subsurface microbial communities in biogeochemical cycling. The video was filmed near the town of Rifle, Colorado at the primary field site for Phase I of the Subsurface Systems Scientific Focus Area 2.0 sponsored by the DOE Office of Biological and Environmental Research.

  13. Apparatus for passive removal of subsurface contaminants

    DOEpatents

    Pemberton, B.E.; May, C.P.; Rossabi, J.

    1997-06-24

    An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere. 7 figs.

  14. Heating systems for heating subsurface formations

    SciTech Connect

    Nguyen, Scott Vinh; Vinegar, Harold J.

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  15. Subsurface Microbes Expanding the Tree of Life

    ScienceCinema

    Banfield, Jillian

    2016-07-12

    Jillian Banfield, Ph.D., UC Berkeley Professor and Berkeley Lab Earth Sciences Division staff scientist and long-time user of the DOE Joint Genome Institute’s resources shares her perspective on how the DOE JGI helps advance her research addressing knowledge gaps related to the roles of subsurface microbial communities in biogeochemical cycling. The video was filmed near the town of Rifle, Colorado at the primary field site for Phase I of the Subsurface Systems Scientific Focus Area 2.0 sponsored by the DOE Office of Biological and Environmental Research.

  16. Sediment chemoautotrophy in the coastal ocean

    NASA Astrophysics Data System (ADS)

    Vasquez-Cardenas, Diana; Meysman, Filip J. R.; van Breugel, Peter; Boschker, Henricus T. S.

    2016-04-01

    oxidation. Sediments with an O2-H2S interface exhibited highest chemoautotrophy activity in the top centimeter via canonical sulfur oxidation, whereas in the presence of electrogenic sulfur oxidation a uniform distribution of chemoautotrophy throughout the top centimeters of the sediment was evidenced. Lowest dark carbon fixation was found in permeable advective-driven sediments with deep oxygen penetration resulting in higher subsurface than surface activity. Hence, the depth-distribution of chemoautotrophy in coastal sediments varies due to several biogeochemical characteristics such as grain size, organic carbon content, presence of filamentous sulfur oxidizing bacteria, and macrofaunal activity.

  17. Water and Solute Transport in the Shallow Subsurface of a Natural Levee

    NASA Astrophysics Data System (ADS)

    Newman, A.; Keim, R.

    2008-12-01

    In riverine wetlands, river channels are separated from backswamps by natural levees that form adjacent to the channel by sediment deposition during floods. The conventional conceptual framework is that backswamp water is impounded and disconnected from surface flow; however, layered sediments, shrink-swell clays, roots and decayed organic matter, and animal burrows likely form preferential pathways for subsurface flow and may substantially affect water and solute exchange between wetlands and river channels. To test the hypothesis that preferential flow is an important pathway of subsurface water movement through natural levees, we measured hydraulic gradients and solute tracers in a 5 x 5 m grid of 19 shallow (2m) monitoring wells within a large representative elementary volume (300 m3) of natural levee in the Atchafalaya Basin, Louisiana. In addition to measuring transient responses to precipitation, we constructed a small reservoir on the backswamp side of the levee to simulate a seasonal hydraulic gradient from the swamp to the adjacent river channel. Results indicate rapid response of water levels in all monitoring wells to the imposed hydraulic gradient as well as rain events, which included two tropical cyclones. In contrast, tracer response was highly variable, both spatially and across events, indicating a complex relationship between subsurface flow processes and water chemistry. Groundwater chemistry indicated spatially variable flowpaths. In some wells, hydraulic response coincided with a chemical shift toward low-conductivity surface water; however, other wells showed similar hydraulic responses but no change in tracer concentrations or even a shift toward higher-conductivity water that was presumably stored in the soil matrix. This spatial variation in tracer response indicates multiple mechanisms of hydraulic response, each of which has important implications for biogeochemical interactions between backswamps and channels in the shallow subsurface

  18. Rain and channel flow supplements to subsurface water beneath hyper-arid ephemeral stream channels

    NASA Astrophysics Data System (ADS)

    Kampf, Stephanie K.; Faulconer, Joshua; Shaw, Jeremy R.; Sutfin, Nicholas A.; Cooper, David J.

    2016-05-01

    In hyper-arid regions, ephemeral stream channels are important sources of subsurface recharge and water supply for riparian vegetation, but few studies have documented the subsurface water content dynamics of these systems. This study examines ephemeral channels in the hyper-arid western Sonoran Desert, USA to determine how frequently water recharges the alluvial fill and identify variables that affect the depth and persistence of recharge. Precipitation, stream stage, and subsurface water content measurements were collected over a three-year study at six channels with varying contributing areas and thicknesses of alluvial fill. All channels contain coarse alluvium composed primarily of sands and gravels, and some locations also have localized layers of fine sediment at 2-3 m depth. Rain alone contributed 300-400 mm of water input to these channels over three years, but water content responses were only detected for 36% of the rain events at 10 cm depth, indicating that much of the rain water was either quickly evaporated or taken up by plants. Pulses of water from rain events were detected only in the top meter of alluvium. The sites each experienced ⩽5 brief flow events, which caused transient saturation that usually lasted only a few hours longer than flow. These events were the only apparent source of water to depths >1 m, and water from flow events quickly percolated past the deepest measurement depths (0.5-3 m). Sustained saturation in the shallow subsurface only developed where there was a near-surface layer of finer consolidated sediments that impeded deep percolation.

  19. Is Europa's Subsurface Water Ocean Warm?

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Ekholm, A. G.; Showman, A. P.; Lorenz, R. D.

    2002-01-01

    Europa's subsurface water ocean may be warm: that is, at the temperature of water's maximum density. This provides a natural explanation of chaos melt-through events and leads to a correct estimate of the age of its surface. Additional information is contained in the original extended abstract.

  20. Lateral gene transfer in the subsurface

    SciTech Connect

    Barkay, Tamar; Sobecky, Patricia

    2007-08-27

    Lateral gene transfer (LGT) is an important adaptive mechanism among prokaryotic organisms. This mechanism is particularly important for the response of microorganisms to changing environmental conditions because it facilitates the transfer of a large number of genes and their rapid expression. Together the transferred genes promote rapid genetic and metabolic changes that may enhance survival to newly established and sometimes hostile environmental conditions. The goal of our project was to examine if and how LGT enhances microbial adaptation to toxic heavy metals in subsurface environments that had been contaminated by mixed wastes due to activities associated with the production of nuclear energy and weapons. This task has been accomplished by dividing the project to several sub-tasks. Thus, we: (1) Determined the level of resistance of subsurface bacterial isolates to several toxic metals, all identified as pollutants of concern in subsurface environments; (2) Designed, tested, and applied, a molecular approach that determined whether metal resistance genes had evolved by LGT among subsurface bacteria; and (3) Developed a DNA hybridization array for the identification of broad host range plasmids and of metal resistance plasmids. The results are briefly summarized below with references to published papers and manuscripts in preparation where details about our research can be found. Additional information may be found in copies of our published manuscripts and conference proceedings, and our yearly reports that were submitted through the RIMS system.

  1. Irrigation strategies using subsurface drip irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsurface drip irrigation (SDI) is practiced on approximately 60,000 ha in the Texas High Plains region of the USA. Adoption of SDI continues to increase in the region. This has been attributed to record drought in Texas and the US Southwest in recent years, declining irrigation well yields, and ev...

  2. BIODEGRADATION OF ATRAZINE IN SUBSURFACE ENVIRONMENTS

    EPA Science Inventory

    The pesticide atrazine is frequently detected in ground water, including ground water used as drinking water. Little information is available on the fate of atrazine in the subsurface, including its biodegradability. The objectives of this study were to evaluate the biodegradabil...

  3. Biomarker Preservation Potential of Subsurface Ecosystems

    NASA Astrophysics Data System (ADS)

    Onstott, T. C.; Harris, R. L.; Sherwood Lollar, B.; Pedersen, K. A.; Colwell, F. S.; Pfiffner, S. M.; Phelps, T. J.; Kieft, T. L.; Bakermans, C.

    2016-05-01

    If surface life emerged on Mars it may have succumbed to a Gaian bottleneck, whereas subsurface life would have continued to grow and evolve sheltered in rocks with sub-freezing saline pore water and their remains preserved in excavated rock.

  4. Characterization of imidacloprid availability in subsurface soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Degradation and sorption/desorption are the most important processes affecting the leaching of pesticides through soil because they control the amount of pesticide available for transport. Once pesticides move past the surface soil layers, variations in subsurface soil physical, chemical, and biolog...

  5. Methods for forming long subsurface heaters

    DOEpatents

    Kim, Dong Sub

    2013-09-17

    A method for forming a longitudinal subsurface heater includes longitudinally welding an electrically conductive sheath of an insulated conductor heater along at least one longitudinal strip of metal. The longitudinal strip is formed into a tubular around the insulated conductor heater with the insulated conductor heater welded along the inside surface of the tubular.

  6. Holocene sea subsurface and surface water masses in the Fram Strait - Comparisons of temperature and sea-ice reconstructions

    NASA Astrophysics Data System (ADS)

    Werner, Kirstin; Müller, Juliane; Husum, Katrine; Spielhagen, Robert F.; Kandiano, Evgenia S.; Polyak, Leonid

    2016-09-01

    Two high-resolution sediment cores from eastern Fram Strait have been investigated for sea subsurface and surface temperature variability during the Holocene (the past ca 12,000 years). The transfer function developed by Husum and Hald (2012) has been applied to sediment cores in order to reconstruct fluctuations of sea subsurface temperatures throughout the period. Additional biomarker and foraminiferal proxy data are used to elucidate variability between surface and subsurface water mass conditions, and to conclude on the Holocene climate and oceanographic variability on the West Spitsbergen continental margin. Results consistently reveal warm sea surface to subsurface temperatures of up to 6 °C until ca 5 cal ka BP, with maximum seawater temperatures around 10 cal ka BP, likely related to maximum July insolation occurring at that time. Maximum Atlantic Water (AW) advection occurred at surface and subsurface between 10.6 and 8.5 cal ka BP based on both foraminiferal and dinocyst temperature reconstructions. Probably, a less-stratified, ice-free, nutrient-rich surface ocean with strong AW advection prevailed in the eastern Fram Strait between 10 and 9 cal ka BP. Weakened AW contribution is found after ca 5 cal ka BP when subsurface temperatures strongly decrease with minimum values between ca 4 and 3 cal ka BP. Cold late Holocene conditions are furthermore supported by high planktic foraminifer shell fragmentation and high δ18O values of the subpolar planktic foraminifer species Turborotalita quinqueloba. While IP25-associated indices as well as dinocyst data suggest a sustained cooling due to a decrease in early summer insolation and consequently sea-ice increase since about 7 cal ka BP in surface waters, planktic foraminiferal data including stable isotopes indicate a slight return of stronger subsurface AW influx since ca 3 cal ka BP. The observed decoupling of surface and subsurface waters during the later Holocene is most likely attributed to a strong

  7. Trends in sediment metal concentrations in the River Avoca, South-east Ireland.

    PubMed

    Gaynor, Anne; Gray, N F

    2004-12-01

    Variation in sediment metal concentrations in the River Avoca, which is severely polluted by acid mine drainage (AMD) discharged from the abandoned sulphur and copper mines in Avoca, is reported. A survey of surface and subsurface sediments was repeated after seven years during exceptionally low flow conditions in 2001. The present study found that the reference (up-stream) site used in the original 1994 study was itself impacted by AMD, showing sediment metal enrichment by AMD to be greater than originally thought. The new reference site contained elevated Pb (570 microg g(-1)) in the subsurface sediment due to abandoned Pb-Zn mines 25 km further upstream. Concentrations of Cu (43 microg g(-1)), Zn (349 microg g(-1)) and Fe (4.0%) were normal for uncontaminated rivers. All the downstream sites showed sediment metal enrichment arising from the AMD (Cu and Zn p < 0.001; Fe p < 0.01). Subsurface concentrations of metals immediately below the mixing zone were Cu 904 microg g-1 (sd 335), Zn 723 microg g-1 (sd 93), Fe 6.3% (sd 1.5) and Pb 463 microg g(-1) (sd 279). Monthly variation in metal concentrations at sites was not significantly different (p > 0.05). Although surface sediment metal concentrations were more variable, they followed similar trends to subsurface sediment. There were no significant differences in the subsurface sediment concentrations for either Cu or Zn over the period 1994 and 2001 immediately below the mines, although at the lowest site Zn had decreased by 35% over the period (p < 0.01). However there was a significant (p < 0.01) decrease over the period in the Fe concentration at all the impacted sites. This corresponds to a reduction in Fe concentration in the AMD and indicates that some remediation has occurred in the river since 1994.

  8. Subsurface barrier verification technologies, informal report

    SciTech Connect

    Heiser, J.H.

    1994-06-01

    One of the more promising remediation options available to the DOE waste management community is subsurface barriers. Some of the uses of subsurface barriers include surrounding and/or containing buried waste, as secondary confinement of underground storage tanks, to direct or contain subsurface contaminant plumes and to restrict remediation methods, such as vacuum extraction, to a limited area. To be most effective the barriers should be continuous and depending on use, have few or no breaches. A breach may be formed through numerous pathways including: discontinuous grout application, from joints between panels and from cracking due to grout curing or wet-dry cycling. The ability to verify barrier integrity is valuable to the DOE, EPA, and commercial sector and will be required to gain full public acceptance of subsurface barriers as either primary or secondary confinement at waste sites. It is recognized that no suitable method exists for the verification of an emplaced barrier`s integrity. The large size and deep placement of subsurface barriers makes detection of leaks challenging. This becomes magnified if the permissible leakage from the site is low. Detection of small cracks (fractions of an inch) at depths of 100 feet or more has not been possible using existing surface geophysical techniques. Compounding the problem of locating flaws in a barrier is the fact that no placement technology can guarantee the completeness or integrity of the emplaced barrier. This report summarizes several commonly used or promising technologies that have been or may be applied to in-situ barrier continuity verification.

  9. IODP Exp 331: Iron-oxidizing Bacteria from the Okinawa Trough Deep Subsurface Biosphere

    NASA Astrophysics Data System (ADS)

    Moyer, C. L.; McAllister, S. M.

    2011-12-01

    Communities of Fe-oxidizing Bacteria (FeOB) are common at sites of hydrothermal venting and are known to form complex communities in microbial mats, hydrothermal sediments, and borehole fluids. Studies at sites around the Pacific Ocean have found the Zetaproteobacteria to be dominant members of these FeOB communities. Preliminary culture-independent analyses indicate that borehole fluids from the deep subsurface may support several novel and distinct Zetaproteobacteria phylotypes (McAllister et al., 2011). Sampling from the deep subsurface at the Iheya North hydrothermal field has provided an opportunity to explore the microbial biodiversity of this unique subsurface habitat. Onboard enrichment experiments for FeOB were carried out at several sites over a wide range of depths as part of IODP Expedition 331. Enrichment experiments were carried out in both microaerophilic and anaerobic environments, with oxygen and nitrate as terminal electron acceptors, respectively. Although tested for the presence of FeOB from 0.23 to 42.45 meters below the seafloor (mbsf), Site C0014 showed little growth except for in the top half meter of hydrothermally unaltered, weakly oxidized sediment. Site C0015, which was diffusely venting and had a relatively low-temperature (~15°C), showed growth throughout the hole with both microaerophilic and anaerobic conditions to a depth of nine mbsf. Growth at this low-temperature site is consistent with previous studies of iron-oxidizing communities, and may correlate best with the borehole community at the Southern Mariana Trough (Kato et al., 2009). At Site C0017, a potential zone of recharge flow (down-welling of cold oxygenated seawater) was traversed from ~26 to 35 mbsf, and at the top of this zone the microaerophilic enrichment experiments showed growth. Growth in this recharge zone represents the deepest subsurface cultivation of FeOB to date, and may lend insight into the colonization of low-temperature vent systems via subsurface fluid

  10. Effects of nitrate on the stability of uranium in a bioreduced region of the subsurface

    SciTech Connect

    Wu, Weimin; Carley, Jack M; Green, Stefan; Luo, Jian; Kelly, Shelly D; Van Nostrand, Joy; Lowe, Kenneth Alan; Mehlhorn, Tonia L; Carroll, Sue L; Boonchayanant, Dr. Benjaporn; Loeffler, Frank E; Jardine, Philip M; Criddle, Craig

    2010-06-01

    The effects of nitrate on the stability of reduced, immobilized uranium were evaluated in field experiments at a U.S. Department of Energy site in Oak Ridge, TN. Nitrate (2.0 mM) was injected into a reduced region of the subsurface containing high levels of previously immobilized U(IV). The nitrate was reduced to nitrite, ammonium, and nitrogen gas; sulfide levels decreased; and Fe(II) levels increased then deceased. Uranium remobilization occurred concomitant with nitrite formation, suggesting nitrate-dependent, iron-accelerated oxidation of U(IV). Bromide tracer results indicated changes in subsurface flowpaths likely due to gas formation and/or precipitate. Desorption-adsorption of uranium by the iron-rich sediment impacted uranium mobilization and sequestration. After rereduction of the subsurface through ethanol additions, background groundwater containing high levels of nitrate was allowed to enter the reduced test zone. Aqueous uranium concentrations increased then decreased. Clone library analyses of sediment samples revealed the presence of denitrifying bacteria that can oxidize elemental sulfur, H{sub 2}S, Fe(II), and U(IV) (e.g., Thiobacillus spp.), and a decrease in relative abundance of bacteria that can reduce Fe(III) and sulfate. XANES analyses of sediment samples confirmed changes in uranium oxidation state. Addition of ethanol restored reduced conditions and triggered a short-term increase in Fe(II) and aqueous uranium, likely due to reductive dissolution of Fe(III) oxides and release of sorbed U(VI). After two months of intermittent ethanol addition, sulfide levels increased, and aqueous uranium concentrations gradually decreased to <0.1 {mu}M.

  11. Adsorption Behavior of Black Carbon for Radioactive Iodine Species in Subsurface Environments

    NASA Astrophysics Data System (ADS)

    Choung, S.; Kim, M.; Um, W.

    2012-12-01

    Releases of radioactive iodines (125/129/131I) into subsurface environments occur during nuclear power plant operations, nuclear weapons tests, and nuclear accidents such as Chernobyl and Fukushima. Environmental concern is mostly for 129I due to high toxicity and long-half life, t1/2=1,600,000 years. The fate and transport of radioactive iodines depend on the speciation in the environments. Sorption of iodate (IO3-) is strongly affected by natural organic matter (NOM) in soil/sediments, while iodide (I-) sorption is less. Although there are numerous forms and compositions of NOM in soil/sediments, previous studies were mostly focused on general organic matter such as humic and fulvic acids. The objective of this study is addressed to evaluate the impact of black carbon as different NOM forms in subsurface environments. Laboratory-produced wood char was used as a representative of black carbon for sorption batch experiments. Commercial humic acid was added to experiments for comparison of iodine sorption behavior to black carbon material. Stable iodine isotope, 127I, was used as a surrogate of radioactive iodine. The 13C-NMR analyses indicated that the wood char consisted of dominantly aromatic chemical structures, while the humic acid exhibited relatively more aliphatic structures than aromaticity. The char and humic acid significantly increased iodide and iodate sorption, respectively. However, iodate sorption on char and iodide sorption on humic acid were negligible in this study. These observations implied different sorption mechanisms between black carbon and humic acid due to different pore structures and chemical compositions. Both of sorption isotherms are dependent on aqueous concentrations, following Freundlich isotherm with n~0.7. The sorption behavior and mechanism of iodine is significantly influenced by the NOM types in soils and sediments, which can enhance iodine retardation in the subsurface environment.

  12. Trajectories of Microbial Community Function in Response to Accelerated Remediation of Subsurface Metal Contaminants

    SciTech Connect

    Firestone, Mary

    2015-01-14

    Objectives of proposed research were to; Determine if the trajectories of microbial community composition and function following organic carbon amendment can be related to, and predicted by, key environmental determinants; Assess the relative importance of the characteristics of the indigenous microbial community, sediment, groundwater, and concentration of organic carbon amendment as the major determinants of microbial community functional response and bioremediation capacity; and Provide a fundamental understanding of the microbial community ecology underlying subsurface metal remediation requisite to successful application of accelerated remediation and long-term stewardship of DOE-IFC sites.

  13. Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: Relationship to lithology and impact processes

    USGS Publications Warehouse

    Cockell, Charles S.; Gronstal, Aaron L.; Voytek, Mary A.; Kirshtein, Julie D.; Finster, Kai; Sanford, Ward E.; Glamoclija, Mihaela; Gohn, Gregroy S.; Powars, David S.; Horton, J. Wright

    2009-01-01

    Asteroid and comet impact events are known to cause profound disruption to surface ecosystems. The aseptic collection of samples throughout a 1.76-km-deep set of cores recovered from the deep subsurface of the Chesapeake Bay impact structure has allowed the study of the subsurface biosphere in a region disrupted by an impactor. Microbiological enumerations suggest the presence of three major microbiological zones. The upper zone (127–867 m) is characterized by a logarithmic decline in microbial abundance from the surface through the postimpact section of Miocene to Upper Eocene marine sediments and across the transition into the upper layers of the impact tsunami resurge sediments and sediment megablocks. In the middle zone (867–1397 m) microbial abundances are below detection. This zone is predominantly quartz sand, primarily composed of boulders and blocks, and it may have been mostly sterilized by the thermal pulse delivered during impact. No samples were collected from the large granite block (1096–1371 m). The lowest zone (below 1397 m) of increasing microbial abundance coincides with a region of heavily impact-fractured, hydraulically conductive suevite and fractured schist. These zones correspond to lithologies influenced by impact processes. Our results yield insights into the influence of impacts on the deep subsurface biosphere.

  14. Analysis of riverbed temperatures to determine the geometry of subsurface water flow around in-stream geomorphological structures

    NASA Astrophysics Data System (ADS)

    Munz, Matthias; Oswald, Sascha E.; Schmidt, Christian

    2016-08-01

    The analytical evaluation of diurnal temperature variation in riverbed sediments provides detailed information on exchange fluxes between rivers and groundwater. The underlying assumption of the stationary, one-dimensional vertical flow field is frequently violated in natural systems where subsurface water flow often has a significant horizontal component. In this paper, we present a new methodology for identifying the geometry of the subsurface flow field using vertical temperature profiles. The statistical analyses are based on model optimisation and selection and are used to evaluate the shape of vertical amplitude ratio profiles. The method was applied to multiple profiles measured around in-stream geomorphological structures in a losing reach of a gravel bed river. The predominant subsurface flow field was systematically categorised in purely vertical and horizontal (hyporheic, parafluvial) components. The results highlight that river groundwater exchange flux at the head, crest and tail of geomorphological structures significantly deviated from the one-dimensional vertical flow, due to a significant horizontal component. The geometry of the subsurface water flow depended on the position around the geomorphological structures and on the river level. The methodology presented in this paper features great potential for characterising the spatial patterns and temporal dynamics of complex subsurface flow geometries by using measured temperature time series in vertical profiles.

  15. Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site

    SciTech Connect

    Green, Stefan; Prakash, Om; Jasrotia, Puja; Overholt, Will; Cardenas, Erick; Hubbard, Daniela; Tiedje, James M.; Watson, David B; Schadt, Christopher Warren; Brooks, Scott C; Kostka, Joel

    2011-01-01

    The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of ribosomal RNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure, and denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as concentration of nitrogen species, oxygen and sampling season did not appear to strongly influence the distribution of Rhodanobacter. Results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

  16. Isolation and Physiology of Bacteria from Contaminated Subsurface Sediments▿ †

    PubMed Central

    Bollmann, Annette; Palumbo, Anthony V.; Lewis, Kim; Epstein, Slava S.

    2010-01-01

    The majority of environmental microorganisms cannot be grown by traditional techniques. Here we employed, and contrasted with conventional plating, an alternative approach based on cultivation of microorganisms inside diffusion chambers incubated within natural samples, followed by subculturing in petri dishes. Using this approach, we isolated microorganisms from subsurface sediments from the Field Research Center (FRC) in Oak Ridge, TN. The sediments were acidic and highly contaminated with uranium, heavy metals, nitrate, and organic pollutants. Phylogenetic analysis of 16S rRNA gene sequences revealed clear differences between diversity of isolates obtained by the diffusion chamber approach and those obtained by conventional plating. The latter approach led to isolation of members of the Alpha- and Gammaproteobacteria, Actinobacteria, and Verrucomicrobia. Isolates obtained via the diffusion chamber approach represented the Alpha-, Beta-, and Gammaproteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Notably, one-third of the isolates obtained by the new method were closely related to species known from previous molecular surveys conducted in the FRC area. Since the initial growth of microorganisms inside diffusion chambers occurred in the presence of the environmental stress factors, we expected the isolates we obtained to be tolerant of these factors. We investigated the physiologies of selected isolates and discovered that the majority were indeed capable of growth under low pH and/or high concentrations of heavy metals and nitrate. This indicated that in contrast to conventional isolation, the diffusion chamber-based approach leads to isolation of species that are novel, exhibit tolerance to extant environmental conditions, and match some of the species previously discovered by molecular methods. PMID:20870785

  17. A subsurface model of the beaver meadow complex

    NASA Astrophysics Data System (ADS)

    Nash, C.; Grant, G.; Flinchum, B. A.; Lancaster, J.; Holbrook, W. S.; Davis, L. G.; Lewis, S.

    2015-12-01

    Wet meadows are a vital component of arid and semi-arid environments. These valley spanning, seasonally inundated wetlands provide critical habitat and refugia for wildlife, and may potentially mediate catchment-scale hydrology in otherwise "water challenged" landscapes. In the last 150 years, these meadows have begun incising rapidly, causing the wetlands to drain and much of the ecological benefit to be lost. The mechanisms driving this incision are poorly understood, with proposed means ranging from cattle grazing to climate change, to the removal of beaver. There is considerable interest in identifying cost-effective strategies to restore the hydrologic and ecological conditions of these meadows at a meaningful scale, but effective process based restoration first requires a thorough understanding of the constructional history of these ubiquitous features. There is emerging evidence to suggest that the North American beaver may have had a considerable role in shaping this landscape through the building of dams. This "beaver meadow complex hypothesis" posits that as beaver dams filled with fine-grained sediments, they became large wet meadows on which new dams, and new complexes, were formed, thereby aggrading valley bottoms. A pioneering study done in Yellowstone indicated that 32-50% of the alluvial sediment was deposited in ponded environments. The observed aggradation rates were highly heterogeneous, suggesting spatial variability in the depositional process - all consistent with the beaver meadow complex hypothesis (Polvi and Wohl, 2012). To expand on this initial work, we have probed deeper into these meadow complexes using a combination of geophysical techniques, coring methods and numerical modeling to create a 3-dimensional representation of the subsurface environments. This imaging has given us a unique view into the patterns and processes responsible for the landforms, and may shed further light on the role of beaver in shaping these landscapes.

  18. Microbial mineral colonization across a subsurface redox transition zone

    SciTech Connect

    Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; Roden, Eric E.

    2015-08-28

    Here our study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ for 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant

  19. Microbial mineral colonization across a subsurface redox transition zone

    DOE PAGES

    Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; ...

    2015-08-28

    Here our study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ formore » 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the RTZ.« less

  20. Microbial mineral colonization across a subsurface redox transition zone

    PubMed Central

    Converse, Brandon J.; McKinley, James P.; Resch, Charles T.; Roden, Eric E.

    2015-01-01

    This study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II)-oxidizing bacteria (FeOB) would preferentially colonize the Fe(II)-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ) at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II) in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013). Sterilized portions of sand+biotite or sand alone were incubated in situ for 5 months within a multilevel sampling (MLS) apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite vs. sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonadaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ) as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II), and HS- oxidizing) taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the RTZ. PMID

  1. The Mars Underground Mole (MUM): A Subsurface Penetration Device with Infrared Reflectance and Raman Spectroscopic Sensing Capability

    NASA Technical Reports Server (NTRS)

    Stoker, C. R.; Richter, L.; Smith, W. H.; Lemke, L. G.; Hammer, P.; Dalton, J. B.; Glass, B.; Zent, A.

    2003-01-01

    Searching for evidence of life on Mars will probably require access to the subsurface. The Martian surface is bathed in ultraviolet radiation which decomposes organic compounds, destroying possible evidence for life. Also, experiments performed by the Viking Landers imply the presence of several strongly oxidizing compounds at the Martian surface that may also play a role in destroying organic compounds near the surface. While liquid water is unstable on the Martian surface, and ice is unstable at the surface at low latitudes, recent results from the Mars Odyssey Gamma Ray Spectrometer experiment indicate that water ice is widely distributed near the surface under a thin cover of dry soil. Organic compounds created by an ancient Martian biosphere might be preserved in such ice-rich layers. Furthermore, accessing the subsurface provides a way to identify unique stratigraphy such as small-scale layering associated with lacustrine sediments. Subsurface access might also provide new insights into the Mars climate record that may be preserved in the Polar Layered Deposits. Recognizing the importance of accessing the subsurface of Mars to the future scientific exploration of the planet, the Mars Surveyor 2007 Science Definition Team called for drilling beneath the surface soils. Subsurface measurements are also cited as high priority in by MEPAG. Recognizing the importance of accessing the Martian subsurface to search for life, the European Space Agency has incorporated a small automated burrowing device called a subsurface penetrometer or Mole onto the Beagle 2 lander planned for 2003 launch. This device, called the Planetary Underground Tool (PLUTO), is a pointed slender cylinder 2 cm wide and 28 cm long equipped with a small sampling device at the pointed end that collects samples and brings them to the surface for analysis. Drawing on the PLUTO design, we are developing a larger Mole carrying sensors for identifying mineralogy, organic compounds, and water.

  2. Impact of agricultural activities on anaerobic processes in stream sediments

    NASA Astrophysics Data System (ADS)

    Schade, J. D.; Ludwig, S.; Nelson, L. C.; Porterfield, J.; Sather, K. L.; Songpitak, M.; Spawn, S.; Weigel, B.

    2013-12-01

    Streams draining agriculture watersheds are subject to significant anthropogenic impacts, including sedimentation from soil erosion and high nitrate input from heavy fertilizer application. Sedimentation degrades habitat and can reduce hydrologic exchange between surface and subsurface waters. Disconnecting surface and subsurface flow reduces oxygen input to hyporheic water, increasing the extent of anoxic zones in stream sediments and creating hotspots for anaerobic processes like denitrification and methanogenesis that can be important sources of nitrous oxide and methane, both powerful greenhouse gases. Increased nitrate input may influence greenhouse gas fluxes from stream sediments by stimulating rates of denitrification and potentially reducing rates of methanogenesis, either through direct inhibition or by increasing competition for organic substrates from denitrifying bacteria. We hypothesized that accumulation of fine sediments in stream channels would result in high rates of methanogenesis in stream sediments, and that increased nitrate input from agricultural runoff would stimulate denitrification and reduce rates of methane production. Our work focused on streams in northern and central Minnesota, in particular on Rice Creek, a small stream draining an agricultural watershed. We used a variety of approaches to test our hypotheses, including surveys of methane concentrations in surface waters of streams ranging in sediment type and nitrate concentration, bottle incubations of sediment from several sites in Rice Creek, and the use of functional gene probes and RNA analyses to determine if genes for these processes are present and being expressed in stream sediments. We found higher methane concentrations in surface water from streams with large deposits of fine sediments, but significantly less methane in these streams when nitrate concentrations were high. We also found high potential for both methanogenesis and denitrification in sediment incubations

  3. Quantification of subsurface pore pressure through IODP drilling

    NASA Astrophysics Data System (ADS)

    Saffer, D. M.; Flemings, P. B.

    2010-12-01

    It is critical to understand the magnitude and distribution of subsurface pore fluid pressure: it controls effective stress and thus mechanical strength, slope stability, and sediment compaction. Elevated pore pressures also drive fluid flows that serve as agents of mass, solute, and heat fluxes. The Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP) have provided important avenues to quantify pore pressure in a range of geologic and tectonic settings. These approaches include 1) analysis of continuous downhole logs and shipboard physical properties data to infer compaction state and in situ pressure and stress, 2) laboratory consolidation testing of core samples collected by drilling, 3) direct downhole measurements using pore pressure probes, 3) pore pressure and stress measurements using downhole tools that can be deployed in wide diameter pipe recently acquired for riser drilling, and 4) long-term monitoring of formation pore pressure in sealed boreholes within hydraulically isolated intervals. Here, we summarize key advances in quantification of subsurface pore pressure rooted in scientific drilling, highlighting with examples from subduction zones, the Gulf of Mexico, and the New Jersey continental shelf. At the Nankai, Costa Rican, and Barbados subduction zones, consolidation testing of cores samples, combined with analysis of physical properties data, indicates that even within a few km landward of the trench, pore pressures in and below plate boundary décollement zones reach a significant fraction of the lithostatic load (λ*=0.25-0.91). These results document a viable and quantifiable mechanism to explain the mechanical weakness of subduction décollements, and are corroborated by a small number of direct measurements in sealed boreholes and by inferences from seismic reflection data. Recent downhole measurements conducted during riser drilling using the modular formation dynamics tester wireline tool (MDT) in a forearc basin ~50

  4. Assessing Uncertainty in Subsurface Transport Predictions Using the ASCEM Toolset

    NASA Astrophysics Data System (ADS)

    Freedman, V.; Chen, X.; Keating, E. H.; Higdon, D. M.; Rockhold, M. L.; Schuchardt, K. L.; Finsterle, S.; Gorton, I.; Freshley, M.

    2011-12-01

    Transport simulation of nonreactive solutes can be used to identify potential pathways of contaminants in the vadose zone and the effectiveness of site remediation technologies. At the BC Cribs site at Hanford in southeastern Washington State, innovative remedial technologies are being explored to address recalcitrant contamination in the deep (~100 m) vadose zone. To identify the effectiveness of the technologies, the impacts of a "no-action" alternative must also be explored. Because only sparse information is available for the geologic conceptual model and the physical and chemical properties of the sediments, there is considerable uncertainty in subsurface transport predictions. In this contribution, the uncertainty of the technetium-99 mass flux to the water table due to parameter uncertainty and variations in the conceptual model are investigated using a newly developed toolset for performing an uncertainty quantification (UQ) analysis. This toolset is part of ASCEM (Advanced Simulation Capability for Environmental Management), a state-of-the-art scientific tool and approach for understanding and predicting contaminant fate and transport in natural and engineered systems. Using the Akuna user environment currently under development, the uncertainty in technetium-99 transport through a two-dimensional, heterogeneous vadose-zone system is quantified with Monte Carlo simulation. Results show that uncertainty in simulated mass fluxes in hydraulic properties can be significant within a single conceptual model, and that significant additional uncertainty can be introduced by conceptual model variation.

  5. Microbial methanogenesis in subsurface oil and coal.

    PubMed

    Meslé, Margaux; Dromart, Gilles; Oger, Philippe

    2013-11-01

    It is now clear that active methanogens are present in the deep-subsurface. This paper reviews microbial population structures and the biodegradation of organic compounds to methane in situ within oil reservoirs and coal deposits. It summarizes our current knowledge of methanogenes and methanogenesis, fermenters, synthrophs and microbial metabolism of complex organic compounds in these two widely occurring organic-rich subsurface environments. This review is not intended to be an exhaustive report of microbial diversity. Rather, it illustrates the similarities and differences between the two environments with specific examples, from the nature of the organic molecules to the methanogenic metabolic pathways and the structure of the microbial populations to demonstrate that widely diverging microbial populations show surprisingly similar metabolic capabilities.

  6. Modeling gas transport in the Martian subsurface

    NASA Astrophysics Data System (ADS)

    Gloesener, Elodie; Karatekin, Özgür; Dehant, Véronique

    2015-04-01

    Modeling gas transport through Martian subsurface and outgassing processes is essential in the study of atmospheric evolution of Mars. We present an overview of gas transport in Martian soil focusing on water vapor and methane diffusion to explain the recent observations of methane in Martian atmosphere with a diffusive transport model. The range of parameters that have the largest effect on transport in Martian conditions is investigated. Among the possible sources of methane, clathrate hydrates destabilization is one potential mechanism. Hydrate stability zone in subsurface is also investigated. In 2016, ExoMars Trace Gas Orbiter (TGO) will have the capabilities to detect and characterize trace gases in Martian atmosphere and will bring additional information to validate the different possible outgassing scenarios.

  7. Spreadsheet log analysis in subsurface geology

    USGS Publications Warehouse

    Doveton, J.H.

    2000-01-01

    Most of the direct knowledge of the geology of the subsurface is gained from the examination of core and drill-cuttings recovered from boreholes drilled by the petroleum and water industries. Wireline logs run in these same boreholes generally have been restricted to tasks of lithostratigraphic correlation and thee location of hydrocarbon pay zones. However, the range of petrophysical measurements has expanded markedly in recent years, so that log traces now can be transformed to estimates of rock composition. Increasingly, logs are available in a digital format that can be read easily by a desktop computer and processed by simple spreadsheet software methods. Taken together, these developments offer accessible tools for new insights into subsurface geology that complement the traditional, but limited, sources of core and cutting observations.

  8. Are sea otters being exposed to subsurface intertidal oil residues from the Exxon Valdez oil spill?

    PubMed

    Boehm, P D; Page, D S; Neff, J M; Brown, J S

    2011-03-01

    Twenty years after the Exxon Valdez oil spill, scattered patches of subsurface oil residues (SSOR) can still be found in intertidal sediments at a small number of shoreline locations in Prince William Sound, Alaska. Some scientists hypothesize that sea otters continue to be exposed to SSOR by direct contact when otters dig pits in search of clams. This hypothesis is examined through site-specific examinations where SSOR and otter-dug pits co-occur. Surveys documented the exact sediment characteristics and locations on the shore at the only three subdivisions where both SSOR and otter pits were found after 2000. Shoreline characteristics and tidal heights where SSOR have persisted are not suitable habitat for sea otters to dig pits during foraging. There is clear separation between areas containing SSOR and otter foraging pits. The evidence allows us to reject the hypothesis that sea otters encounter and are being exposed by direct contact to SSOR.

  9. PLFA analyses of microbial communities associated with PAH-contaminated riverbank sediment.

    PubMed

    Pratt, Brenda; Riesen, Roland; Johnston, Carl G

    2012-10-01

    Sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) is widely distributed in aquatic ecosystems. The microbial community structure of riverbank PAH-contaminated sediments was investigated using phospholipid-derived fatty acid (PLFA) analysis. Surface and subsurface riverbank sediment was collected from a highly contaminated site and from an uncontaminated site along the Mahoning River, OH. PAH concentrations, physical sediment characteristics, and other microbial community parameters (biomass as phospholipid phosphate (PLP) and activity) were also measured. PAHs were detected in all samples but were only quantifiable in the contaminated (250 μg/g g(-1)) subsurface sediment. Subsurface samples from both locations showed very similar PLP values and distribution of PLFAs, with 27-37 % of the microbial community structure being composed of sulfate reducing and other anaerobic bacteria. Principal components analysis indicated no correlation between PAH contamination and PLFA diversity. Although PLP and phospholipid fatty acid measurements of bacterial communities did not reflect the environmental differences among sites, the highly PAH-contaminated sediment showed the highest measured microbial activity (reduction of 1,200 nmol INT g(-1) h(-1)), likely from a population adapted to environmental pollutants, rates that are much higher than measured in many uncontaminated soil and sediment systems. These data warrant further investigation into community structure at the genetic level and indicate potential for bioremediation by indigenous microbes.

  10. Spatial and Vertical Variability in Bacterial Community Structure in the Sediment of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.; Xie, W.; Chen, S.; Zhang, C. L.

    2014-12-01

    The ocean subsurface contains one of the largest pools of reactive carbon and nitrogen on earth, and thus serves as the largest realm for microbial life. However, the microbial communities that drive deep-subsurface geochemical processes are vastly unexplored. In this study, the bacterial community structure in the subsurface of the South China Sea were examined using sediment cores collected from shelf (water depth 667 m) to slope (water depth 3840 m). High-throughput sequencing of the bacterial 16S rRNA genes from the sediment samples resulted in a total of 270,000 sequences with each sample averaging about 10,000 sequences. In all sediment cores, the 16S rRNA gene copies of bacteria were highest in the surface sediment and decreased with the core depth. The bacterial community was dominated by Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes. In most of the sediment cores, Proteobacteria dominated surface sediment samples and decreased with depth. The community structure showed no significant difference among the stations at different water depths, which indicates that bacterial distribution in the sediment is not influenced by the water column above. However, stations along the transect from Pearl River canyon to the deep basin were grouped together by cluster analysis, which indicates that bacterial community structure at these stations may bear the same consequence of sedimentary processes of the deep South China Sea.

  11. Spatiotemporal variability in peatland subsurface methane dynamics

    NASA Astrophysics Data System (ADS)

    Strack, M.; Waddington, J. M.

    2008-06-01

    Peatlands are large natural sources of atmospheric methane (CH4). While many studies have measured CH4 emissions to the atmosphere, less is known about the stock and residence time of subsurface CH4. In this study we examined dissolved CH4 concentration in near-surface peatland pore waters of a poor fen near Québec City, Canada, in order to (1) investigate the variability in and potential controls on these concentrations and (2) combine measured dissolved CH4 concentration with estimated bubble CH4 stock and measured CH4 fluxes to estimate the mean residence time of subsurface CH4. Concentrations ranged from 1 to 450 μM during both study seasons. Depth profiles were generally consistent at one location within the peatland throughout the sampling period but varied between locations. Patterns with depth were not well correlated to pore water pH or EC; however, changes in CH4 concentration through time in the upper 30 cm were related to temperature and water table at some locations. Depth profiles taken at 2- to 5-cm intervals revealed discrete concentration "spikes" which were often maintained throughout the season and are likely related to bubble CH4 dynamics. Estimated subsurface CH4 stocks indicate that even when relatively low bubble volume (5% of peat volume) is assumed, bubble CH4 accounted for greater than half of total stocks. Calculated mean residence times were 28-120 days. This implies that CH4 flux may lag changes in water table and temperature which happen on shorter timescales (hours or days). To improve our description of subsurface CH4 stocks, links between dissolved and bubble CH4 stocks and peatland CH4 residence time, coincident measurement of pore water CH4 concentrations, entrapped gas content and composition, diffusive CH4 flux, and ebullition are required.

  12. Drill Embedded Nanosensors For Planetary Subsurface Exploration

    NASA Technical Reports Server (NTRS)

    Li, Jing

    2014-01-01

    We have developed a carbon nanotube (CNT) sensor for water vapor detection under Martian Conditions and the miniaturized electronics can be embedded in the drill bit for collecting sensor data and transmit it to a computer wirelessly.This capability will enable the real time measurement of ice during drilling. With this real time and in-situ measurement, subsurface ice detection can be easy, fast, precise and low cost.

  13. Subsurface materials management and containment system

    DOEpatents

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2006-10-17

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  14. Subsurface materials management and containment system

    DOEpatents

    Nickelson, Reva A.; Richardson, John G.; Kosteinik, Kevin M.; Sloan, Paul A.

    2004-07-06

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  15. Radionuclide Sensors for Subsurface Water Monitoring

    SciTech Connect

    Timothy DeVol

    2006-06-30

    Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

  16. Activation of Peroxymonosulfate by Subsurface Minerals

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Teel, Amy L.; Watts, Richard J.

    2016-08-01

    In situ chemical oxidation (ISCO) has become a widely used technology for the remediation of soil and groundwater. Although peroxymonosulfate is not a common oxidant source for ISCO, its chemical structure is similar to the ISCO reagents hydrogen peroxide and persulfate, suggesting that peroxymonosulfate may have the beneficial properties of each of these oxidants. Peroxymonosulfate activation in the presence of subsurface minerals was examined as a basis for ISCO, and possible reactive species (hydroxyl radical, sulfate radical, and reductants + nucleophiles) generated in the mineral-activated peroxymonosulfate systems were investigated. Rates of peroxymonosulfate decomposition and generation rates of reactive species were studied in the presence of three iron oxides, one manganese oxide, and three soil fractions. The iron oxide hematite-activated peroxymonosulfate system most effectively degraded the hydroxyl radical probe nitrobenzene. Reductants + nucleophiles were not generated in mineral-activated peroxymonosulfate systems. Use of the probe compound anisole in conjunction with scavengers demonstrated that both sulfate radical and hydroxyl radical are generated in mineral-activated peroxymonosulfate systems. In order to confirm the activation of peroxymonosulfate by subsurface minerals, one natural soil and associated two soil fractions were evaluated as peroxymonosulfate catalysts. The natural soil did not effectively promote the generation of oxidants; however, the soil organic matter was found to promote the generation of reductants + nucleophiles. The results of this research show that peroxymonosulfate has potential as an oxidant source for ISCO applications, and would be most effective in treating halogenated contaminants when soil organic matter is present in the subsurface.

  17. Subsurface heat flow in an urban environment

    NASA Astrophysics Data System (ADS)

    Ferguson, Grant; Woodbury, Allan D.

    2004-02-01

    The subsurface temperature field beneath Winnipeg, Canada, is significantly different from that of the surrounding rural areas. Downward heat flow to depths as great as 130 m has been noted in some areas beneath the city and groundwater temperatures in a regional aquifer have risen by as much as 5°C in some areas. Numerical simulation of heat transport supports the conjecture that these temperature changes can be largely attributed to heat loss from buildings and the temperature at any given point is sensitive to the distance from and the age of any buildings. The effect is most noticable when buildings are closely spaced, which is typical of urban areas. Temperature measurements in areas more than a few hundred meters away from any heated structure were only a few tenths of a degree Celsius greater than those observed outside the city, suggesting that other reasons for increases in subsurface temperature, such as changes in surface cover or climate change, may be responsible for some of the some of the observed increase in temperatures. These sources of additional heat to the subsurface make it difficult to resolve information on past climates from temperatures measured in boreholes and monitoring wells. In some areas, the temperature increases may also have an impact on geothermal energy resources. This impact might be in the form of an increase in heat pump efficiency or in the case of the Winnipeg area, a decrease in the efficiency of direct use of groundwater for cooling.

  18. Chemical inversion in the subsurface hydrosphere

    SciTech Connect

    Yezhov, Yu.A.

    1980-09-01

    A quite common nature of chemical inversion in subsurface hydrosphere is shown in examples of several oil- and gas-bearing regions of the USSR. In particular, when the data of sampling from deep wells of the Volgo-Urals, Mangyshlak, and Western Turkmenian regions were compared, it became obvious that the composite chemical profile of subsurface hydrosphere consists of a vertical alternation of three zones: of increasing (I-II-IIIa genetic types of subsurface waters), maximum (IIIb), and decreasing water mineralization (III'a-II'-I'). The depth of occurrence of the lower inversion branch of zonality depends on the geotectonic activity at depth. It is closer to the Earth's surface in regions of Alpine tectogenesis, whereas in regions of ancient folding it lies at great depths which have not yet been reached by most deep wells. The formation of the inversion zone in the Earth's crust is connected with penetration from below ascending demineralized fluids of sodium bicarbonate type (I'). The latter is due to the presence at great depths of large quantities of free carbonic acid which is involved in hydrolytic processes of decomposition of sodium-containing minerals and produces sodium-type waters.

  19. Resonant seismic emission of subsurface objects

    SciTech Connect

    Korneev, Valeri A.

    2009-04-15

    Numerical modeling results and field data indicate that some contrasting subsurface objects (such as tunnels, caves, pipes, filled pits, and fluid-filled fractures) are capable of generating durable resonant oscillations after trapping seismic energy. These oscillations consist of surface types of circumferential waves that repeatedly propagate around the object. The resonant emission of such trapped energy occurs primarily in the form of shear body waves that can be detected by remotely placed receivers. Resonant emission reveals itself in the form of sharp resonant peaks for the late parts of the records, when all strong direct and primary reflected waves are gone. These peaks were observed in field data for a buried barrel filled with water, in 2D finite-difference modeling results, and in the exact canonical solution for a fluid-filled sphere. A computed animation for the diffraction of a plane wave upon a low-velocity elastic sphere confirms the generation of resonances by durable surface waves. Resonant emission has characteristic quasi-hyperbolic traveltime patterns on shot gathers. The inversion of these patterns can be performed in the frequency domain after muting the strong direct and primary scattered waves. Subsurface objects can be detected and imaged at a single resonance frequency without an accurate knowledge of source trigger time. The imaging of subsurface objects requires information about the shear velocity distribution in an embedding medium, which can be done interactively during inversion.

  20. Subsurface barrier integrity verification using perfluorocarbon tracers

    SciTech Connect

    Sullivan, T.M.; Heiser, J.; Milian, L.; Senum, G.

    1996-12-01

    Subsurface barriers are an extremely promising remediation option to many waste management problems. Gas phase tracers include perfluorocarbon tracers (PFT`s) and chlorofluorocarbon tracers (CFC`s). Both have been applied for leak detection in subsurface systems. The focus of this report is to describe the barrier verification tests conducted using PFT`s and analysis of the data from the tests. PFT verification tests have been performed on a simulated waste pit at the Hanford Geotechnical facility and on an actual waste pit at Brookhaven National Laboratory (BNL). The objective of these tests were to demonstrate the proof-of-concept that PFT technology can be used to determine if small breaches form in the barrier and for estimating the effectiveness of the barrier in preventing migration of the gas tracer to the monitoring wells. The subsurface barrier systems created at Hanford and BNL are described. The experimental results and the analysis of the data follow. Based on the findings of this study, conclusions are offered and suggestions for future work are presented.

  1. Subsurface urban heat islands in German cities.

    PubMed

    Menberg, Kathrin; Bayer, Peter; Zosseder, Kai; Rumohr, Sven; Blum, Philipp

    2013-01-01

    Little is known about the intensity and extension of subsurface urban heat islands (UHI), and the individual role of the driving factors has not been revealed either. In this study, we compare groundwater temperatures in shallow aquifers beneath six German cities of different size (Berlin, Munich, Cologne, Frankfurt, Karlsruhe and Darmstadt). It is revealed that hotspots of up to +20K often exist, which stem from very local heat sources, such as insufficiently insulated power plants, landfills or open geothermal systems. When visualizing the regional conditions in isotherm maps, mostly a concentric picture is found with the highest temperatures in the city centers. This reflects the long-term accumulation of thermal energy over several centuries and the interplay of various factors, particularly in heat loss from basements, elevated ground surface temperatures (GST) and subsurface infrastructure. As a primary indicator to quantify and compare large-scale UHI intensity the 10-90%-quantile range UHII(10-90) of the temperature distribution is introduced. The latter reveals, in comparison to annual atmospheric UHI intensities, an even more pronounced heating of the shallow subsurface.

  2. Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Fredrickson, Jim K.; Bjornstad, Bruce N.; Konopka, Allan

    2012-02-01

    The microbial diversity in subsurface sediments at the Hanford Site's 300 Area in southeastern Washington State was investigated by analyzing 21 samples recovered from depths that ranged from 9 to 52 m. Approximately 8000 non-chimeric Bacterial and Archaeal 16S rRNA gene sequences were analyzed across geological strata that contain a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (Operational Taxonomic Units, defined at the 97% identity level). Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (based upon Chao1 estimator) was highest (>700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic transition zone, richness was about 325 and declined to less than 50 in the deeper reduced zones. The Bacterial community in the oxic Hanford and Ringold Formations contained members of 9 major well-recognized phyla as well 30 as unusually high proportions of 3 candidate divisions (GAL15, NC10, and SPAM). The deeper Ringold strata were characterized by low OTU richness and a very high preponderance (ca. 90%) of Proteobacteria. The study has greatly expanded the intralineage phylogenetic diversity within some major divisions. These subsurface sediments have been shown to contain a large number of phylogenetically novel microbes, with substantial heterogeneities between sediment samples from the same geological formation.

  3. Linear absorption coefficient of beryllium in the 50-300-A wavelength range. [bandpass filter materials for ultraviolet astronomy instrumentation

    NASA Technical Reports Server (NTRS)

    Barstow, M. A.; Lewis, M.; Petre, R.

    1983-01-01

    Transmittances of thin-film filters fabricated for an extreme-UV astronomy sounding-rocket experiment yield values for the linear absorption coefficient of beryllium in the 50-300-A wavelength range, in which previous measurements are sparse. The inferred values are consistent with the lowest data previously published and may have important consequences for extreme-UV astronomers.

  4. 7 CFR 330.300a - Administrative instructions exempting soil from parts of Canada from certain restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Administrative instructions exempting soil from parts... FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Soil, Stone, And Quarry Products § 330.300a Administrative instructions exempting soil from...

  5. 7 CFR 330.300a - Administrative instructions exempting soil from parts of Canada from certain restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Administrative instructions exempting soil from parts... FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Soil, Stone, And Quarry Products § 330.300a Administrative instructions exempting soil from...

  6. 7 CFR 330.300a - Administrative instructions exempting soil from parts of Canada from certain restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Administrative instructions exempting soil from parts... FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Soil, Stone, And Quarry Products § 330.300a Administrative instructions exempting soil from...

  7. 7 CFR 330.300a - Administrative instructions exempting soil from parts of Canada from certain restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Administrative instructions exempting soil from parts... FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Soil, Stone, And Quarry Products § 330.300a Administrative instructions exempting soil from...

  8. 7 CFR 330.300a - Administrative instructions exempting soil from parts of Canada from certain restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Administrative instructions exempting soil from parts... FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Soil, Stone, And Quarry Products § 330.300a Administrative instructions exempting soil from...

  9. The T300A Crohn's disease risk polymorphism impairs function of the WD40 domain of ATG16L1

    PubMed Central

    Boada-Romero, Emilio; Serramito-Gómez, Inmaculada; Sacristán, María P.; Boone, David L.; Xavier, Ramnik J.; Pimentel-Muiños, Felipe X.

    2016-01-01

    A coding polymorphism of human ATG16L1 (rs2241880; T300A) increases the risk of Crohn's disease and it has been shown to enhance susceptibility of ATG16L1 to caspase cleavage. Here we show that T300A also alters the ability of the C-terminal WD40-repeat domain of ATG16L1 to interact with an amino acid motif that recognizes this region. Such alteration impairs the unconventional autophagic activity of TMEM59, a transmembrane protein that contains the WD40 domain-binding motif, and disrupts its normal intracellular trafficking and its ability to engage ATG16L1 in response to bacterial infection. TMEM59-induced autophagy is blunted in cells expressing the fragments generated by caspase processing of the ATG16L1-T300A risk allele, whereas canonical autophagy remains unaffected. These results suggest that the T300A polymorphism alters the function of motif-containing molecules that engage ATG16L1 through the WD40 domain, either by influencing this interaction under non-stressful conditions or by inhibiting their downstream autophagic signalling after caspase-mediated cleavage. PMID:27273576

  10. In situ time-series measurements of subseafloor sediment properties

    USGS Publications Warehouse

    Wheatcroft, R.A.; Stevens, A.W.; Johnson, R.V.

    2007-01-01

    The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein. ASP consists of a four-electrode, Wenner-type resistivity probe and a thermistor that log data at 0.1-cm vertical intervals over a 58-cm vertical profile. To avoid resampling the same spot on the seafloor, the probes are moved horizontally within a 20 times 100-cm-2 area in one of three preselected patterns. Memory and power capacities permit sampling at hourly intervals for up to 3-mo duration. The system was tested in a laboratory tank and shown to be able to resolve high-frequency sediment consolidation, as well as changes in sediment roughness. In a field test off the southern coast of France, the system collected resistivity and temperature data at hourly intervals for 16 d. Coupled with environmental data collected on waves, currents, and suspended sediment, the ASP is shown to be useful for understanding temporal evolution of subsurface sediment porosity, although no large depositional or erosional events occurred during the deployment. Following a rapid decrease in bottom-water temperature, the evolution of the subsurface temperature field was consistent with the 1-D thermal diffusion equation coupled with advection in the upper 3-4 cm. Collectively, the laboratory and field tests yielded promising results on time-dependent seabed change.

  11. Quantifying sediment sources in a lowland agricultural catchment pond using (137)Cs activities and radiogenic (87)Sr/(86)Sr ratios.

    PubMed

    Le Gall, Marion; Evrard, Olivier; Foucher, Anthony; Laceby, J Patrick; Salvador-Blanes, Sébastien; Thil, François; Dapoigny, Arnaud; Lefèvre, Irène; Cerdan, Olivier; Ayrault, Sophie

    2016-10-01

    Soil erosion often supplies high sediment loads to rivers, degrading water quality and contributing to the siltation of reservoirs and lowland river channels. These impacts are exacerbated in agricultural catchments where modifications in land management and agricultural practices were shown to accelerate sediment supply. In this study, sediment sources were identified with a novel tracing approach combining cesium ((137)Cs) and strontium isotopes ((87)Sr/(86)Sr) in the Louroux pond, at the outlet of a lowland cultivated catchment (24km(2), Loire River basin, France) representative of drained agricultural areas of Northwestern Europe. Surface soil (n=36) and subsurface channel bank (n=17) samples were collected to characterize potential sources. Deposited sediment (n=41) was sampled across the entire surface of the pond to examine spatial variation in sediment deposits. In addition, a 1.10m sediment core was sampled in the middle of the pond to reconstruct source variations throughout time. (137)Cs was used to discriminate between surface and subsurface sources, whereas (87)Sr/(86)Sr ratios discriminated between lithological sources. A distribution modeling approach quantified the relative contribution of these sources to the sampled sediment. Results indicate that surface sources contributed to the majority of pond (μ 82%, σ 1%) and core (μ 88%, σ 2%) sediment with elevated subsurface contributions modeled near specific sites close to the banks of the Louroux pond. Contributions of the lithological sources were well mixed in surface sediment across the pond (i.e., carbonate sediment contribution, μ 48%, σ 1% and non-carbonate sediment contribution, μ 52%, σ 3%) although there were significant variations of these source contributions modeled for the sediment core between 1955 and 2013. These fluctuations reflect both the progressive implementation of land consolidation schemes in the catchment and the eutrophication of the pond. This original sediment

  12. Mineral dissolution and secondary precipitation on quartz sand in simulated Hanford tank solutions affecting subsurface porosity

    NASA Astrophysics Data System (ADS)

    Wang, Guohui; Um, Wooyong

    2012-11-01

    Highly alkaline nuclear waste solutions have been released from underground nuclear waste storage tanks and pipelines into the vadose zone at the US Department of Energy's Hanford Site in Washington, causing mineral dissolution and re-precipitation upon contact with subsurface sediments. High pH caustic NaNO3 solutions with and without dissolved Al were reacted with quartz sand through flow-through columns stepwise at 45, 51, and 89 °C to simulate possible reactions between leaked nuclear waste solution and primary subsurface mineral. Upon reaction, Si was released from the dissolution of quartz sand, and nitrate-cancrinite [Na8Si6Al6O24(NO3)2] precipitated on the quartz surface as a secondary mineral phase. Both steady-state dissolution and precipitation kinetics were quantified, and quartz dissolution apparent activation energy was determined. Mineral alteration through dissolution and precipitation processes results in pore volume and structure changes in the subsurface porous media. In this study, the column porosity increased up to 40.3% in the pure dissolution column when no dissolved Al was present in the leachate, whereas up to a 26.5% porosity decrease was found in columns where both dissolution and precipitation were observed because of the presence of Al in the input solution. The porosity change was also confirmed by calculation using the dissolution and precipitation rates and mineral volume changes.

  13. Flat meridional temperature gradient in the early Eocene in the subsurface rather than surface ocean

    NASA Astrophysics Data System (ADS)

    Ho, Sze Ling; Laepple, Thomas

    2016-08-01

    The early Eocene (49-55 million years ago) is a time interval characterized by elevated surface temperatures and atmospheric CO2 (refs ,), and a flatter-than-present latitudinal surface temperature gradient. The multi-proxy-derived flat temperature gradient has been a challenge to reproduce in model simulations, especially the subtropical warmth at the high-latitude surface oceans, inferred from the archaeal lipid-based palaeothermometry, . Here we revisit the interpretation by analysing a global collection of multi-proxy temperature estimates from sediment cores spanning millennia to millions of years. Comparing the variability between proxy types, we demonstrate that the present interpretation overestimates the magnitude of past climate changes on all timescales. We attribute this to an inappropriate calibration, which reflects subsurface ocean but is calibrated to the sea surface, where the latitudinal temperature gradient is steeper. Recalibrating the proxy to the temperatures of subsurface ocean, where the signal is probably formed, yields colder -temperatures and latitudinal gradient consistent with standard climate model simulations of the Eocene climate, invalidating the apparent, extremely warm polar sea surface temperatures. We conclude that there is a need to reinterpret -inferred marine temperature records in the literature, especially for reconstructions of past warm climates that rely heavily on this proxy as reflecting subsurface ocean.

  14. Mineral Dissolution and Secondary Precipitation on Quartz Sand in Simulated Hanford Tank Solutions Affecting Subsurface Porosity

    SciTech Connect

    Wang, Guohui; Um, Wooyong

    2012-11-23

    Highly alkaline nuclear waste solutions have been released from underground nuclear waste storage tanks and pipelines into the vadose zone at the U.S. Department of Energy’s Hanford Site in Washington, causing mineral dissolution and re-precipitation upon contact with subsurface sediments. High pH caustic NaNO3 solutions with and without dissolved Al were reacted with quartz sand through flow-through columns stepwise at 45, 51, and 89°C to simulate possible reactions between leaked nuclear waste solution and primary subsurface mineral. Upon reaction, Si was released from the dissolution of quartz sand, and nitrate-cancrinite [Na8Si6Al6O24(NO3)2] precipitated on the quartz surface as a secondary mineral phase. Both steady-state dissolution and precipitation kinetics were quantified, and quartz dissolution apparent activation energy was determined. Mineral alteration through dissolution and precipitation processes results in pore volume and structure changes in the subsurface porous media. In this study, the column porosity increased up to 40.3% in the pure dissolution column when no dissolved Al was present in the leachate, whereas up to a 26.5% porosity decrease was found in columns where both dissolution and precipitation were observed because of the presence of Al in the input solution. The porosity change was also confirmed by calculation using the dissolution and precipitation rates and mineral volume changes.

  15. Microbial Signatures of Two Marine Subsurface Sites in the Same Geographic Region (Eastern Equatorial Pacific)

    NASA Astrophysics Data System (ADS)

    Martino, A. J.; Biddle, J.; House, C. H.

    2012-12-01

    Drilling expeditions from which marine subsurface sediment samples are obtained are extremely expensive, and thus, it is not possible to sample every location of the ocean floor extensively. As a result, estimations of the contribution of subsurface microbial communities in geochemical cycles and nutrient reservoirs are based on generalizations, which assume that subsurface microbial communities in close proximity are similar as long as there are not major chemical or physical differences in the environments. However, to date, there has been no study comparing the microbial communities in two or more highly similar and geographically close drill cores. In this study, we were fortunate to have obtained samples from two locations within the Eastern Equatorial Pacific, at sites which were both geographically close, and geochemically and lithologically very similar. Using samples from three depths at both of these sites, we are performing a molecular comparison of the microbial communities using next generation metagenomic sequencing. This comparison encompasses both phylogenetic and functional properties. In addition to the comparison between sites, we are also employing a methodology duplicate with one sample, which has rarely been done with metagenomic studies. Finally, we are also exploring the effects of whole genome amplification (WGA) on sequence analysis of extracted DNA samples, via the use of multiple WGA methods on aliquots of the same sample, with an unamplified control as a reference. Preliminary data from the first sample sequenced shows the over-amplification of archaea—particularly Thaumarchaeota—after amplification using multiple displacement amplification, as compared with the unamplified control.

  16. Evidence for extensive gene flow and Thermotoga subpopulations in subsurface and marine environments.

    PubMed

    Nesbø, Camilla L; S Swithers, Kristen; Dahle, Håkon; Haverkamp, Thomas H A; Birkeland, Nils-Kåre; Sokolova, Tatiana; Kublanov, Ilya; Zhaxybayeva, Olga

    2015-07-01

    Oil reservoirs represent a nutrient-rich ecological niche of the deep biosphere. Although most oil reservoirs are occupied by microbial populations, when and how the microbes colonized these environments remains unanswered. To address this question, we compared 11 genomes of Thermotoga maritima-like hyperthermophilic bacteria from two environment types: subsurface oil reservoirs in the North Sea and Japan, and marine sites located in the Kuril Islands, Italy and the Azores. We complemented our genomes with Thermotoga DNA from publicly available subsurface metagenomes from North America and Australia. Our analysis revealed complex non-bifurcating evolutionary history of the isolates' genomes, suggesting high amounts of gene flow across all sampled locations, a conjecture supported by numerous recombination events. Genomes from the same type of environment tend to be more similar, and have exchanged more genes with each other than with geographically close isolates from different types of environments. Hence, Thermotoga populations of oil reservoirs do not appear isolated, a requirement of the 'burial and isolation' hypothesis, under which reservoir bacteria are descendants of the isolated communities buried with sediments that over time became oil reservoirs. Instead, our analysis supports a more complex view, where bacteria from subsurface and marine populations have been continuously migrating into the oil reservoirs and influencing their genetic composition. The Thermotoga spp. in the oil reservoirs in the North Sea and Japan probably entered the reservoirs shortly after they were formed. An Australian oil reservoir, on the other hand, was likely colonized very recently, perhaps during human reservoir development.

  17. Tertiary subsurface solution in the Mississippian Leadville Limestone geothermal aquifer of Colorado

    SciTech Connect

    Bridges, L.W.D.; McCarthy, K.

    1990-04-01

    Subsurface solution by geothermal waters during the Tertiary rather than karst formation during the Paleozoic may account for the solution features found at the top of the Mississippian Leadville Limestone. Evidence at Guernsey, Wyoming suggests overlying sediments were lithified long before solution features formed. At Treasure Mountain, Colorado, a 108 ft (33 m) interval above the fill material is also Mississippian, which may indicate nearly continuous Mississippian deposition in the axis of the Mississippian seaway. It is unlikely that a karst surface could have developed in this restricted time period. The chert breccias of Guernsey and Treasure Mountain show no evidence of abrasion. This chert appears to have been precipitated from silica dissolved by geothermal waters in Tertiary time and later fractured by slumping. Earlier workers found much debris from overlying formations in Leadville solution features, but most dismissed the possibility of late-state subsurface dissolution contemporaneous with ore deposition. The authors postulate that subsurface solution took place in Tertiary time during the heating phase associated with orogeny, mineralization, and igneous activity. Dissolution was localized by pressure differences and fluid flow near major faults associated with mineralization. The largest solution areas are associated with deep-seated faults such as the Rio Grande Rift. Moderate to intense local solution is associated with mineralization. Small-scale, local solution and alteration may be associated with topographically controlled hot spring systems.

  18. Subsurface gas offshore of northern California and its link to submarine geomorphology

    USGS Publications Warehouse

    Yun, J.W.; Orange, D.L.; Field, M.E.

    1999-01-01

    The northern California continental margin contains evidence of abundant subsurface gas and numerous seafloor features that suggest a causative link between gas expulsion and geomorphology. Analyses of seismic reflection, sidescan sonar, and high-resolution multibeam bathymetric data show that the occurrence of subbottom gas and the migration processes beneath the shelf differ from those beneath the slope. Subsurface gas, inferred from enhanced reflectors and other geophysical indicators, is spatially variable and related more to total depth and stratigraphy than to underlying structure, with the exception of one band of gas that follows the regional structural trend. Shallow depressions on the seafloor (pockmarks) are used to infer expulsion sites. The largest zone of acoustically impenetrable subsurface gas occurs between water depths of 100 m and 300 m, where expulsion features are rare. The upper slope (water depths 400-600 m) has a high concentration of pockmarks (diameter 10-20 m), in contrast to a near-absence of pockmarks at water depths shallower than 400 m. Of nearly 4000 pockmarks observed on sidescan sonar records, more than 95% are located in water depths deeper than 400 m. Bottom simulating reflectors (BSRs) on some seismic reflection profiles indicate the possible presence of gas hydrate. We find that gas and pore-fluid migration in the offshore Eel River Basin is: (1) correlated to surface morphology; (2) a contributor to seabed roughness; (3) a significant mode of sediment redistribution on the upper slope; and (4) potentially a factor in large slope failures.

  19. Reactive transport benchmarks for subsurface environmental simulation

    SciTech Connect

    Steefel, Carl I.; Yabusaki, Steven B.; Mayer, K. U.

    2015-06-01

    Over the last 20 years, we have seen firsthand the evolution of multicomponent reactive transport modeling and the expanding range and increasing complexity of subsurface applications it is being used to address. There is a growing reliance on reactive transport modeling (RTM) to address some of the most compelling issues facing our planet: climate change, nuclear waste management, contaminant remediation, and pollution prevention. While these issues are motivating the development of new and improved capabilities for subsurface environmental modeling using RTM (e.g., biogeochemistry from cell-scale physiology to continental-scale terrestrial ecosystems, nonisothermal multiphase conditions, coupled geomechanics), there remain longstanding challenges in characterizing the natural variability of hydrological, biological, and geochemical properties in subsurface environments and limited success in transferring models between sites and across scales. An equally important trend over the last 20 years is the evolution of modeling from a service sought out after data has been collected to a multifaceted research approach that provides (1) an organizing principle for characterization and monitoring activities; (2) a systematic framework for identifying knowledge gaps, developing and integrating new knowledge; and (3) a mechanistic understanding that represents the collective wisdom of the participating scientists and engineers. There are now large multidisciplinary projects where the research approach is model-driven, and the principal product is a holistic predictive simulation capability that can be used as a test bed for alternative conceptualizations of processes, properties, and conditions. Much of the future growth and expanded role for RTM will depend on its continued ability to exploit technological advancements in the earth and environmental sciences. Advances in measurement technology, particularly in molecular biology (genomics), isotope fractionation, and high

  20. Combining multiple fallout radionuclides (137Cs, 7Be, 210Pbxs) improves our understanding of sediment source dynamics in tropical rivers

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Laceby, J. P.; Huon, S.; Lefèvre, I.; Sengtaheuanghoung, O.; Ribolzi, O.

    2015-12-01

    Soil erosion has accelerated as a result of land use change, increasing the sediment supply to rivers worldwide. A thorough knowledge of sediment dynamics is required to design efficient management measures to control erosion and reduce sediment delivery from catchments. Fallout radionuclides are often used separately to provide spatial (137Cs) or temporal (7Be, 210Pbxs) information on sediment sources. In this study, we examine their combined application to simultaneously model spatial and temporal sediment source dynamics. To this end, potential sediment sources (n=84) and suspended sediment (n=16) were collected at two stations in a 12 km² catchment in Northern Laos during the first flood of the 2014 wet season. Part of the source material was directly sampled in ephemeral flow occurring on hillslopes to avoid the grain size selectivity problems that may occur during erosion and river transport processes. A distribution modelling approach quantified the relative contributions of recently eroded surface (labelled with both 7Be and 137Cs), recently eroded subsurface (depleted in both 7Be and 137Cs), re-suspended surface (depleted in 7Be and labelled with 137Cs) and re-suspended subsurface sources (enriched in 7Be and depleted in 137Cs). At an upstream sampling location, surface sources contributed the majority of sediment (55%) whereas subsurface sources dominated the supply of sediment downstream (74%). Importantly, re-suspended subsurface sources, labelled with 7Be, were a significant sediment source at the catchment outlet (60%). This approach demonstrates the utility of combining multiple radionuclides when investigating spatial and temporal sediment source dynamics in tropical catchments. In the future, sampling of source material in ephemeral flows occurring on hillslopes should be encouraged. Furthermore, the proposed approach should be tested in larger catchments to guide the implementation of efficient erosion control measures.

  1. Effects of Surface and Subsurface Bed Material Composition on Gravel Transport and Flow Competence Relations—Possibilities for Prediction

    NASA Astrophysics Data System (ADS)

    Bunte, K.; Abt, S. R.; Swingle, K. W.; Cenderelli, D. A.; Gaeuman, D. A.

    2014-12-01

    Bedload transport and flow competence relations are difficult to predict in coarse-bedded steep streams where widely differing sediment supply, bed stability, and complex flow hydraulics greatly affect amounts and sizes of transported gravel particles. This study explains how properties of bed material surface and subsurface size distributions are directly related to gravel transport and may be used for prediction of gravel transport and flow competence relations. Gravel transport, flow competence, and bed material size were measured in step-pool and plane-bed streams. Power functions were fitted to gravel transport QB=aQb and flow competence Dmax=cQd relations; Q is water discharge. Frequency distributions of surface FDsurf and subsurface FDsub bed material were likewise described by power functions FDsurf=hD j and FDsub=kDm fitted over six 0.5-phi size classes within 4 to 22.4 mm. Those gravel sizes are typically mobile even in moderate floods. Study results show that steeper subsurface bed material size distributions lead to steeper gravel transport and flow competence relations, whereas larger amounts of sediment contained in those 6 size bedmaterial classes (larger h and k) flatten the relations. Similarly, steeper surface size distributions decrease the coefficients of the gravel transport and flow competence relations, whereas larger amounts of sediment within the six bed material classes increase the intercepts of gravel transport and flow competence relations. Those relations are likely causative in streams where bedload stems almost entirely from the channel bed as opposed to direct (unworked) contributions from hillslopes and tributaries. The exponent of the subsurface bed material distribution m predicted the gravel transport exponent b with r2 near 0.7 and flow competence exponent d with r2 near 0.5. The intercept of bed surface distributions h increased the intercept a of gravel transport and c of the flow competence relations with r2 near 0.6.

  2. Subsurface geology of Medina Group (Lower Silurian) and Clinton Group (Lower to Upper Silurian) of New York

    SciTech Connect

    Kearney, M.W.

    1984-12-01

    The depositional environments and geologic history of the Medina Group (Lower Silurian) and the Clinton Group (Lower to Upper Silurian) of New York have been interpreted from a regional subsurface study using approximately 250 ..gamma..-ray logs and 125 sample logs. A sequence of paleogeographic maps illustrate the geologic history and depositional environments associated with this predominantly clastic, rock sequence. Seven principle depositional environments are recognized on the basis of subsurface sedimentary facies. The Silurian clastic rocks were deposited during an overall marine transgression that was interrupted by three major progradational phases. The orogenic episodes represented by these progradational phases steadily decreased in intensity. The sediment influx during the first progradational phase was large enough to produce a deltaic system that extended throughout New York. During the second progradational phase, the sediment influx was small relative to the first event, and subsidence probably increased from loading of the Grimsby sediments. The deltaic system that developed during this time was restricted to east-central New York. The final progradational phase represents an even smaller influx of terrigenous material; only a linear clastic shoreline developed in eastern New York. This phase marks the last major influx of terrigenous clastic sediments until Devonian time.

  3. Physical and chemical controls on habitats for life in the deep subsurface beneath continents and ice.

    PubMed

    Parnell, John; McMahon, Sean

    2016-01-28

    The distribution of life in the continental subsurface is likely controlled by a range of physical and chemical factors. The fundamental requirements are for space to live, carbon for biomass and energy for metabolic activity. These are inter-related, such that adequate permeability is required to maintain a supply of nutrients, and facies interfaces invite colonization by juxtaposing porous habitats with nutrient-rich mudrocks. Viable communities extend to several kilometres depth, diminishing downwards with decreasing porosity. Carbon is contributed by recycling of organic matter originally fixed by photosynthesis, and chemoautotrophy using crustal carbon dioxide and methane. In the shallow crust, the recycled component predominates, as processed kerogen or hydrocarbons, but abiotic carbon sources may be significant in deeper, metamorphosed crust. Hydrogen to fuel chemosynthesis is available from radiolysis, mechanical deformation and mineral alteration. Activity in the subcontinental deep biosphere can be traced through the geological record back to the Precambrian. Before the colonization of the Earth's surface by land plants, a geologically recent event, subsurface life probably dominated the planet's biomass. In regions of thick ice sheets the base of the ice sheet, where liquid water is stable and a sediment layer is created by glacial erosion, can be regarded as a deep biosphere habitat. This environment may be rich in dissolved organic carbon and nutrients accumulated from dissolving ice, and from weathering of the bedrock and the sediment layer.

  4. Geophysical Monitoring of Coupled Microbial and Geochemical Processes During Stimulated Subsurface Bioremediation

    SciTech Connect

    Williams, Kenneth H.; Kemna, Andreas; Wilkins, Michael J.; Druhan, Jennifer L.; Arntzen, Evan V.; N'Guessan, A. Lucie; Long, Philip E.; Hubbard, Susan S.; Banfield, Jillian F.

    2009-08-05

    Understanding how microorganisms alter their physical and chemical environment during bioremediation is hindered by our inability to resolve subsurface microbial activity with high spatial resolution. Here we demonstrate the use of a minimally invasive geophysical technique to monitor stimulated microbial activity during acetate amendment in an aquifer near Rifle, Colorado. During electrical induced polarization (IP) measurements, spatiotemporal variations in the phase response between imposed electric current and the resultant electric field correlated with changes in groundwater geochemistry accompanying stimulated iron and sulfate reduction and sulfide mineral precipitation. The magnitude of the phase response varied with measurement frequency (0.125 and 1 Hz) andwasdependent upon the dominant metabolic process. The spectral effect was corroborated using a biostimulated column experiment containing Rifle sediments and groundwater. Fluids and sediments recovered from regions exhibiting an anomalous phase response were enriched in Fe(II), dissolved sulfide, and cell-associated FeS nanoparticles. The accumulation of mineral precipitates and electroactive ions altered the ability of pore fluids to conduct electrical charge, accounting for the anomalous IP response and revealing the usefulness of multifrequency IP measurements for monitoring mineralogical and geochemical changes accompanying stimulated subsurface bioremediation.

  5. Physical and chemical controls on habitats for life in the deep subsurface beneath continents and ice

    PubMed Central

    Parnell, John; McMahon, Sean

    2016-01-01

    The distribution of life in the continental subsurface is likely controlled by a range of physical and chemical factors. The fundamental requirements are for space to live, carbon for biomass and energy for metabolic activity. These are inter-related, such that adequate permeability is required to maintain a supply of nutrients, and facies interfaces invite colonization by juxtaposing porous habitats with nutrient-rich mudrocks. Viable communities extend to several kilometres depth, diminishing downwards with decreasing porosity. Carbon is contributed by recycling of organic matter originally fixed by photosynthesis, and chemoautotrophy using crustal carbon dioxide and methane. In the shallow crust, the recycled component predominates, as processed kerogen or hydrocarbons, but abiotic carbon sources may be significant in deeper, metamorphosed crust. Hydrogen to fuel chemosynthesis is available from radiolysis, mechanical deformation and mineral alteration. Activity in the subcontinental deep biosphere can be traced through the geological record back to the Precambrian. Before the colonization of the Earth's surface by land plants, a geologically recent event, subsurface life probably dominated the planet's biomass. In regions of thick ice sheets the base of the ice sheet, where liquid water is stable and a sediment layer is created by glacial erosion, can be regarded as a deep biosphere habitat. This environment may be rich in dissolved organic carbon and nutrients accumulated from dissolving ice, and from weathering of the bedrock and the sediment layer. PMID:26667907

  6. Lower Silurian-Upper Ordovician subsurface glacial outwash deposits, northern Saudi Arabia

    SciTech Connect

    Dobson, P.B. )

    1991-08-01

    Recently acquired seismic data reinterpreted well information in northwest Saudi Arabia extends outcropping Lower Silurian to Upper Ordovician Zarqa/Sarah glacial and periglacial deposits into the subsurface. These deposits range from northeast-trending outwash-filled channels deeply incised into the underlying Ordovician Qasim and the Cambrian-Ordovician Saq Formation in the east. A southwest source for these sediments is implied by this new data. This supports previously interpreted source directions mapped from outcrop. It also correlates with the position of the Arabian plate relative to known Gonwanaland ice caps during the Early Silurian-Late Ordovician. The recognition of glacial outwash sediments in the subsurface provides new insight into the continuity and environments of deposition of the Qasim Formation members in northwest Saudi Arabia. The hydrocarbon-prone Lower Silurian Qusaiba Member of the Qalibah Formation overlies the Zarqa/Sarah Formations. The Qusaiba represents a rapid transgression of the Paleo-Tethys Sea during the final melting of the Gondwanaland ice caps. The seal-source characteristics of the Qusaiba Member, combined with the good porosity and permeability of the underlying outwash deposits, suggest a prospective hydrocarbon exploration play. Gas is produced from this reservoir in the Risha field of eastern Jordan.

  7. Nitrate bioreduction in redox-variable low permeability sediments

    SciTech Connect

    Yan, Sen; Liu, Yuanyuan; Liu, Chongxuan; Shi, Liang; Shang, Jianying; Shan, Huimei; Zachara, John M.; Fredrickson, Jim K.; Kennedy, David W.; Resch, Charles T.; Thompson, Christopher J.; Fansler, Sarah J.

    2015-09-09

    Denitrification is a microbial process that reduces nitrate and nitrite to nitrous oxide (N2O) or dinitrogen (N2) with a strong implication to global nitrogen cycling and climate change. This paper reports the effect of sediment redox conditions on the rate and end product of denitrification. The sediments were collected from a redox transition zone consisting of oxic and reduced layers at US Department of Energy’s Hanford Site where N2O was locally accumulated in groundwater. The results revealed that denitrification rate and end product varied significantly with initial sediment redox state. The denitrification rate was relatively faster, limited by organic carbon content and bioavailability in the oxic sediment. In contrast, the rate was much slower in the reduced sediment, limited by biomass and microbial function. A significant amount of N2O was accumulated in the reduced sediment; while in the oxic sediment, N2O was further reduced to N2. RT-PCR analysis revealed that nosZ, the gene that codes for N2O reductase, was below detection in the reduced sediment. The results implied that redox transition zones can be important sinks or sources of N2O depending on local biogeochemical and microbial conditions, and are important systems for understanding and modeling denitrification in subsurface environments.

  8. Biodegradation of polycyclic aromatic hydrocarbons by Sphingomonas strains isolated from the terrestrial subsurface.

    PubMed

    Shi, T; Fredrickson, J K; Balkwill, D L

    2001-05-01

    Several strains of Sphingomonas isolated from deep Atlantic coastal plain aquifers at the US Department of Energy Savannah River Site (SRS) near Aiken, SC were shown to degrade a variety of aromatic hydrocarbons in a liquid culture medium. Sphingomonas aromaticivorans strain B0695 was the most versatile of the five strains examined. This strain was able to degrade acenaphthene, anthracene, phenanthrene, 2,3-benzofluorene, 2-methylnaphthalene, 2,3-dimethylnaphthalene, and fluoranthene in the presence of 400 mg l(-1) Tween 80. Studies involving microcosms composed of aquifer sediments showed that S. aromaticivorans B0695 could degrade phenanthrene effectively in sterile sediment and could enhance the rate at which this compound was degraded in nonsterile sediment. These findings indicate that it may be feasible to carry out (or, at least, to enhance) in situ bioremediation of phenanthrene-contaminated soils and subsurface environments with S. aromaticivorans B0695. In contrast, strain B0695 was unable to degrade fluoranthene in microcosms containing aquifer sediments, even though it readily degraded this polynuclear aromatic hydrocarbon (PAH) in a defined liquid growth medium.

  9. Submarine cementation of subsurface Pliocene carbonates from the interior of Great Bahama Bank

    SciTech Connect

    Beach, D.K.

    1993-11-01

    Thick intervals of early Pliocene subtidal carbonate sediments in the subsurface of northwestern Great Bahama Bank were lithified by submarine cement. This cementation, subsequently altered by meteoric diagenesis, occurred over a broad expanse of the platform interior. It shows that submarine cements can lithify thick packstone and grainstone intervals in the interior of large shallow-water carbonate shelves and platforms given open circulation, moderate to slow sedimentation rates, and minimal accumulation of fine sediments. A submarine origin for these cements is inferred from direct and circumstantial evidence, including: (1) regional depositional and diagenetic setting; (2) fabric and habit similar to modern submarine cements; (3) alteration of cements from mineralogically unstable precursors indicated by (a) abundant inclusions, (b) relict precursor fabric, and commonly (c) yellowish coloration, (d) undulose crystal extinction, and (e) selective leaching of specific generations of cement or cement types; (4) sutured mid-pore crystal contacts; (5) precipitation coeval with accumulation of internal marine sediment; (6) association with organisms requiring a firm substrate for attachment. These considerations may help other workers recognize submarine cements in ancient carbonate rocks.

  10. Physiologically anaerobic microorganisms of the deep subsurface. Final performance report, June 1, 1990--August 31, 1993

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1993-10-01

    Anaerobic bacteria were isolated from deep subsurface sediment samples taken at study sites in Idaho (INEL) and Washington (HR) by culturing on dilute and concentrated medium. Morphologically distinct colonies were purified, and their responses to 21 selected physiological tests were determined. Although the number of isolates was small (18 INEL, 27 HR) some general patterns could be determined. Most strains could utilize all the carbon sources, however the glycerol and melizitose utilization was positive for 50% or less of the HR isolates. Catalase activity (27.78% at INEL, 74.07% at HR) and tryptophan metabolism (11.12% at INEL, 40.74% at HR) were significantly different between the two study sites. MPN and viable counts indicate that sediments near the water table yield the greatest numbers of anaerobes. Deeper sediments also appear to be more selective with the greatest number of viable counts on low-nutrient mediums. Likewise, only strictly obligate anaerobes were found in the deepest sediment samples. Selective media indicated the presence of methanogens, acetogens, and sulfate reducers at only the HR site.

  11. Biodegradation of polycyclic aromatic hydrocarbons by Sphingomonas strains isolated from the terrestrial subsurface

    SciTech Connect

    Shi, T; Fredrickson, Jim K.; Balkwill, David L.

    2001-05-01

    Several strains of Sphingomonas isolated from deep Atlantic coastal plain aquifers at the US Department of Energy Savannah River Site (SRS) near Aiken, SC were shown to degrade a variety of aromatic hydrocarbons in a liquid culture medium. Sphingomonas aromaticivorans strain B0695 was the most versatile of the five strains examined. This strain was able to degrade acenaphthene, anthracene, phenanthrene, 2,3-benzofluorene, 2-methyl naphthalene, 2,3-dimethylnaphthalene, and fluoranthene in the presence of 400 mg l(-1) Tween 80. Studies involving microcosms composed of aquifer sediments showed that S. aromaticivorans B0695 could degrade phenanthrene effectively in sterile sediment and could enhance the rate at which this compound was degraded in nonsterile sediment. These findings indicate that it may be feasible to carry out (or, at least, to enhance) in situ bioremediation of phenanthrene-contaminated soils and subsurface environments with S. aromaticivorans B0695. In contrast, stra in B0695 was unable to degrade fluoranthene in microcosms containing aquifer sediments, even though it readily degraded this polynuclear aromatic hydrocarbon (PAH) in a defined liquid growth medium.

  12. Deglacial Subsurface Temperature Change in the Tropical North Atlantic Linked to Atlantic Meridional Overturning Circulation Variability

    NASA Astrophysics Data System (ADS)

    Schmidt, M. W.; Hertzberg, J. E.; Them, T. R.; Parker, A. O.; Chang, P.

    2011-12-01

    Coupled ocean-atmosphere modeling experiments conducted under both the present and Last Glacial Maximum (LGM) conditions indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly coupled to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes (Zhang, 2007; Chang et al., 2008; Chiang et al., 2008; Otto-Bliesner and Brady, 2009). While a slowdown of AMOC in these experiments results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming due to rapid reorganizations of ocean circulation patterns (Wan et al., 2009). To test the hypothesis that subsurface temperature change in the TNA is coupled to AMOC variability across abrupt climate events over the last deglacial, we reconstruct Mg/Ca-temperature and δ18O records from both surface (Globigerinoides ruber, upper mixed layer) and sub-thermocline dwelling (Globorotalia truncatulinoides, 350-500 m depth) planktonic foraminifera, as well as from the benthic species Cibicidoides pachyderma in the southern Caribbean Sea sediment core VM12-107 (11.33 °N, 66.63 °W; 1079 m; 18 cm/kyr sedimentation rate). Reconstructed sea surface temperatures (SSTs) indicate a gradual warming in the TNA starting at ~19 kyr BP with small cold reversals of ~1.5 °C during Heinrich Event 1 (H1) and the Younger Dryas (YD). In contrast, LGM subsurface temperatures were as much as 2.5 °C warmer than Late Holocene values and H1 and the YD are marked by the warmest subsurface temperatures characterized by abrupt temperature increases as large as 4-5 °C. In addition, benthic Mg/Ca ratios during the YD and H1 increase by 50% relative to Holocene intervals, suggesting significant warming extending to 1079 m water depth across these events. Comparison of our subsurface temperature records with the Bermuda Rise 231Pa/230Th proxy record of AMOC variability (McManus et al., 2004) indicates a strong correlation between

  13. Applied gas tracers for subsurface and surface hydrology

    NASA Astrophysics Data System (ADS)

    Elliot, T.; Kalin, R. M.; MacKinnon, P. A.; McNeill, G. W.; Murphy, J. L.

    2003-04-01

    Tracer methods can be broadly taken to be techniques for obtaining information about an environmental and/or engineering system or some part of a system (eg transit times in media, permeability, dispersivity, internal structure, subsurface activities, etc.) by observing the behaviour of a specific substance (natural or anthropogenic) either injected into or inherently added within that system. Recent studies at QUB have focussed on applied tracer methods using dissolved inert gases both as geochemically conservative tracers in groundwater systems (providing structural information, flow-paths, transit times, physical transport properties) and also as non-conservative, bulk partitioning agents to determine re-aeration coefficients (K_2 values) in surface stream systems or for characterising the presence and extent of nonaqueous phases in subsurface groundwater systems (eg NAPLs at contaminated land sites). Noble gas applications as applied tracers particularly are being investigated because of their low natural background levels and high sensitivity of determination (by GC-MS), and lack of any taste, odour, colour and toxicity problems -- these latter properties suggesting a more "environmentally-friendly" type of tracer either to protect potable water (eg public) supplies under investigation or so as not to impact intrinsic reactive processes in the system being traced. Both laboratory column investigations and field studies are presented, emphasising the utility of applied gas tracing for hydrological investigations. Mackinnon, P.A., Elliot, T., Zhao, Y.Q., Murphy, J.L. &Kalin, R.M. (2002) Evaluation of a novel technique for measuring reaeration in rivers. In C.A. Brebbia, P. Zanetti (Eds.) Development and Application of Computer Techniques to Environmental Studies IX. WIT Press, Southampton, UK. pp.531--540. McNeill, G.W., Yang, Y.S., Elliot, T., Kalin, R.M. (2001) Krypton gas as a novel applied tracer of groundwater flow in a fissured sandstone aquifer. In K

  14. Identifying sediment sources in a drained lowland agricultural catchment: the application of a novel thorium-based particle size correction in sediment fingerprinting

    NASA Astrophysics Data System (ADS)

    Laceby, J. P.; Le Gall, M.; Foucher, A.; Salvador-Blanes, S.; Evrard, O.; Lefèvre, I.; Cerdan, O.; Desmet, M.

    2015-12-01

    Soil erosion is one of the main processes influencing land and water degradation at the global scale. Identifying the main sediment sources is therefore essential for effective soil erosion management. Accordingly, caesium-137 (137Cs) concentrations were used to quantify the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel Thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of suspended sediment loads on riverine systems in similar lowland drained agricultural catchments.

  15. Subsurface Conditions Controlling Uranium Incorporation in Iron Oxides: A Redox Stable Sink

    SciTech Connect

    Fendorf, Scott

    2016-04-05

    mechanism may help to explain U retention in some geologic materials, improving our understanding of U-based geochronology and the redox status of ancient geochemical environments. Additionally, U(VI) may be incorporated within silicate minerals though encapsulation of U-bearing iron oxides, leading to a redox stable solid. Our research detailing previously unrecognized mechanism of U incorporation within sediment minerals may even lead to new approaches for in situ contamination remediation techniques, and will help refine models of U fate and transport in reduced subsurface zones.

  16. Development of in-aquifer heat testing for high resolution subsurface thermal-storage capability characterisation

    NASA Astrophysics Data System (ADS)

    Seibertz, Klodwig Suibert Oskar; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2016-03-01

    The ongoing transition from fossil fuels to alternative energy source provision has resulted in increased geothermal uses as well as storage of the shallow subsurface. Existing approaches for exploration of shallow subsurface geothermal energy storage often lack the ability to provide information concerning the spatial variability of thermal storage parameters. However, parameter distributions have to be known to ensure that sustainable geothermal use of the shallow subsurface can take place - especially when it is subject to intensive usage. In this paper, we test a temperature decay time approach to obtain in situ, direct, qualitative, spatial high-resolution information about the distribution of thermal storage capabilities of the shallow subsurface. To achieve this, temperature data from a high-resolution Fibre-Optic-Distributed-Temperature-Sensing device, as well as data from conventional Pt100-temperature-sensors were collected during a heat injection test. The latter test was used to measure the decay time of temperature signal dissipation of the subsurface. Signal generation was provided by in-aquifer heating with a temperature self-regulating electric heating cable. Heating was carried out for 4.5 days. After this, a cooling period of 1.5 weeks was observed. Temperature dissipation data was also compared to Direct-Push-derived high-resolution (hydro-)geological data. The results show that besides hydraulic properties also the bedding and compaction state of the sediment have an impact on the thermal storage capability of the saturated subsurface. The temperature decay time approach is therefore a reliable method for obtaining information regarding the qualitative heat storage capability of heterogeneous aquifers for the use with closed loop system geothermal storage systems. Furthermore, this approach is advantageous over other commonly used methods, e.g. soil-sampling and laboratory analysis, as even small changes in (hydro-)geological properties lead to

  17. Denitrifying bacteria from the terrestrial subsurface exposed to mixed waste contamination

    SciTech Connect

    Green, Stefan; Prakash, Om; Gihring, Thomas; Akob, Denise M.; Jasrotia, Puja; Jardine, Philip M; Watson, David B; Brown, Steven D; Palumbo, Anthony Vito; Kostka, Joel

    2010-01-01

    In terrestrial subsurface environments where nitrate is a critical groundwater contaminant, few cultivated representatives are available with which to verify the metabolism of organisms that catalyze denitrification. In this study, five species of denitrifying bacteria from three phyla were isolated from subsurface sediments exposed to metal radionuclide and nitrate contamination as part of the U.S. Department of Energy s Oak Ridge Integrated Field Research Challenge (OR-IFRC). Isolates belonged to the genera Afipia and Hyphomicrobium (Alphaproteobacteria), Rhodanobacter (Gammaproteobacteria), Intrasporangium (Actinobacteria) and Bacillus (Firmicutes). Isolates from the phylum Proteobacteria were confirmed as complete denitrifiers, whereas the Gram-positive isolates reduced nitrate to nitrous oxide. Ribosomal RNA gene analyses reveal that bacteria from the genus Rhodanobacter comprise a diverse population of circumneutral to moderately acidophilic denitrifiers at the ORIFRC site, with a high relative abundance in areas of the acidic source zone. Rhodanobacter species do not contain a periplasmic nitrite reductase and have not been previously detected in functional gene surveys of denitrifying bacteria at the OR-IFRC site. Sequences of nitrite and nitrous oxide reductase genes were recovered from the isolates and from the terrestrial subsurface by designing primer sets mined from genomic and metagenomic data and from draft genomes of two of the isolates. We demonstrate that a combination of cultivation, genomic and metagenomic data are essential to the in situ characterization of denitrifiers and that current PCR-based approaches are not suitable for deep coverage of denitrifying microorganisms. Our results indicate that the diversity of denitrifiers is significantly underestimated in the terrestrial subsurface.

  18. Shallow Subsurface Structures of Volcanic Fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Nash, J.; Mitchell, K. L.; Parness, A.

    2015-12-01

    Volcanic fissure vents are a difficult geologic feature to quantify. They are often too thin to document in detail with seismology or remote geophysical methods. Additionally, lava flows, lava drain back, or collapsed rampart blocks typically conceal a fissure's surface expression. For exposed fissures, quantifying the surface (let along sub0surface) geometric expression can become an overwhelming and time-consuming task given the non-uniform distribution of wall irregularities, drain back textures, and the larger scale sinuosity of the whole fissure system. We developed (and previously presented) VolcanoBot to acquire robust characteristic data of fissure geometries by going inside accessible fissures after an eruption ends and the fissure cools off to <50 C. Data from VolcanoBot documents the fissure conduit geometry with a near-IR structured light sensor, and reproduces the 3d structures to cm-scale accuracy. Here we present a comparison of shallow subsurface structures (<30 m depth) within the Mauna Ulu fissure system and their counterpart features at the vent-to-ground-surface interface. While we have not mapped enough length of the fissure to document sinuosity at depth, we see a self-similar pattern of irregularities on the fissure walls throughout the entire shallow subsurface, implying a fracture mechanical origin similar to faults. These irregularities are, on average, 1 m across and protrude 30 cm into the drained fissure. This is significantly larger than the 10% wall roughness addressed in the engineering literature on fluid dynamics, and implies that magma fluid dynamics during fissure eruptions are probably not as passive nor as simple as previously thought. In some locations, it is possible to match piercing points across the fissure walls, where the dike broke the wall rock in order to propagate upwards, yet in other locations there are erosional cavities, again, implying complex fluid dynamics in the shallow sub-surface during fissure eruptions.

  19. Noble gas fractionation during subsurface gas migration

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Larson, Toti E.; Hesse, Marc A.

    2016-09-01

    Environmental monitoring of shale gas production and geological carbon dioxide (CO2) storage requires identification of subsurface gas sources. Noble gases provide a powerful tool to distinguish different sources if the modifications of the gas composition during transport can be accounted for. Despite the recognition of compositional changes due to gas migration in the subsurface, the interpretation of geochemical data relies largely on zero-dimensional mixing and fractionation models. Here we present two-phase flow column experiments that demonstrate these changes. Water containing a dissolved noble gas is displaced by gas comprised of CO2 and argon. We observe a characteristic pattern of initial co-enrichment of noble gases from both phases in banks at the gas front, followed by a depletion of the dissolved noble gas. The enrichment of the co-injected noble gas is due to the dissolution of the more soluble major gas component, while the enrichment of the dissolved noble gas is due to stripping from the groundwater. These processes amount to chromatographic separations that occur during two-phase flow and can be predicted by the theory of gas injection. This theory provides a mechanistic basis for noble gas fractionation during gas migration and improves our ability to identify subsurface gas sources after post-genetic modification. Finally, we show that compositional changes due to two-phase flow can qualitatively explain the spatial compositional trends observed within the Bravo Dome natural CO2 reservoir and some regional compositional trends observed in drinking water wells overlying the Marcellus and Barnett shale regions. In both cases, only the migration of a gas with constant source composition is required, rather than multi-stage mixing and fractionation models previously proposed.

  20. Using Muons to Image the Subsurface.

    SciTech Connect

    Bonal, Nedra; Cashion, Avery Ted; Cieslewski, Grzegorz; Dorsey, Daniel J.; Foris, Adam; Miller, Timothy J.; Roberts, Barry L; Su, Jiann-Cherng; Dreesen, Wendi; Green, J. Andrew; Schwellenbach, David

    2016-11-01

    Muons are subatomic particles that can penetrate the earth 's crust several kilometers and may be useful for subsurface characterization . The absorption rate of muons depends on the density of the materials through which they pass. Muons are more sensitive to density variation than other phenomena, including gravity, making them beneficial for subsurface investigation . Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and the detector, much like a CAT scan. Currently, muon tomography can resolve features to the sub-meter scale. This work consists of three parts to address the use of muons for subsurface characterization : 1) assess the use of muon scattering for estimating density differences of common rock types, 2 ) using muon flux to detect a void in rock, 3) measure muon direction by designing a new detector. Results from this project lay the groundwork for future directions in this field. Low-density objects can be detected by muons even when enclosed in high-density material like lead, and even small changes in density (e.g. changes due to fracturing of material) can be detected. Rock density has a linear relationship with muon scattering density per rock volume when this ratio is greater than 0.10 . Limitations on using muon scattering to assess density changes among common rock types have been identified. However, other analysis methods may show improved results for these relatively low density materials. Simulations show that muons can be used to image void space (e.g. tunnels) within rock but experimental results have been ambiguous . Improvements are suggested to improve imaging voids such as tunnels through rocks. Finally, a muon detector has been designed and tested to measure muon direction, which will improve signal-to-noise ratio and help address fundamental questions about the source of upgoing muons .

  1. Tree Distributions, Subsurface Characteristics and Nitrogen Cycling

    NASA Astrophysics Data System (ADS)

    Brunner, L.; Wallace, M. C.; Brush, G.

    2014-12-01

    This study examines the connection between vegetation and geologic, soil and hydrologic subsurface characteristics of a natural deciduous forest in Oregon Ridge Park, located in the Piedmont physiographic province in Maryland, USA. A preliminary study showed the relationship between nitrogen cycling and four different species occurring on a coarse grained schist and a fine grained schist. Mineralization values for Liriodendon tulipifera were positive on the coarser grained substrate and negative on the fine grained substrate. Nitrification values were positive on both substrates. Mineralization and nitrification values were both positive for Quercus prinus on both the coarse and fine substrates. Mineralization values for Acer rubrum were negative on the coarse substrate and positive on the finer substrate, while mineralization for Quercus rubra was negative on the coarse substrate and positive on the fine schist. Nitrification was positive for Q. rubra on the coarse schist and both positive and negative on the fine schist. Resistivity analyses were performed in collaboration with the Wyoming Center for Environmental Hydrology and Geophysics (WyCEHG) along two perpendicular transects at the study site. This analysis provides indirect information on subsurface conductivity, with low resistivity being interpreted as subsurface water or clay. One transect crossed a valley with a first-order stream in the center, while the second transect was taken along the break and slope of the hillslope. All trees were identified and diameter at breast height (DBH) measured in sixty-three randomly located plots along both transects. A principle components analysis of all tree data showed four associations of species. The plots were labelled as to association. The position of the associations along the transects show a relationship between wet, dry and mesic associations with differences in transect resistivity.

  2. Holocene Sea Surface and Subsurface Water Mass Variability Reconstructed from Temperature and Sea-ice Proxies in Fram Strait

    NASA Astrophysics Data System (ADS)

    Werner, Kirstin; Spielhagen, Robert F.; Müller, Juliane; Husum, Katrine; Kandiano, Evgenia S.; Polyak, Leonid

    2016-04-01

    In two high-resolution sediment cores from the West Spitsbergen continental margin we investigated planktic foraminiferal, biomarker and dinocyst proxy data in order to reconstruct surface and subsurface water mass variability during the Holocene. The two study sites are today influenced by northward flowing warm and saline Atlantic Water. Both foraminiferal and dinocyst (de Vernal et al., 2013) temperature reconstructions indicate a less-stratified, ice-free, nutrient-rich summer surface ocean with strong Atlantic Water advection between 10.6 and 8.5 cal ka BP, likely related to maximum July insolation during the early Holocene. Sea surface to subsurface water temperatures of up to 6°C prevailed until ca 5 cal ka BP. A weakened contribution of Atlantic Water is found when subsurface temperatures strongly decreased with minimum values between ca 4 and 3 cal ka BP. High planktic foraminifer shell fragmentation and increased oxygen isotope values of the subpolar planktic foraminifer species Turborotalita quinqueloba as well as increasing concentrations of the sea ice biomarker IP25 further indicate cool conditions. Indices associated with IP25 as well as dinocyst data suggest a sustained cooling and consequently sea-ice increase during the late Holocene. However, planktic foraminiferal data indicate a slight return of stronger subsurface influx of Atlantic Water since ca 3 cal ka BP. The observed decoupling of cooling surface and warming subsurface waters during the later Holocene might be attributed to a strong pycnocline layer separating cold sea-ice fed surface waters from enhanced subsurface Atlantic Water advection. Reference: de Vernal, A., Hillaire-Marcel, C., Rochon, A., Fréchette, B., Henry, M., Solignac, S., Bonnet, S., 2013. Dinocyst-based reconstructions of sea ice cover concentration during the Holocene in the Arctic Ocean, the northern North Atlantic Ocean and its adjacent seas. Quaternary Science Reviews 79, 111-121.

  3. Legacy Sediments in U.S. River Environments: Atrazine and Aggradation to Zinc and Zoobenthos

    NASA Astrophysics Data System (ADS)

    Wohl, E.

    2014-12-01

    Legacy sediments are those that are altered by human activities. Alterations include (i) human-caused aggradation (and subsequent erosion), such as sediment accumulating upstream from relict or contemporary dams, (ii) human-caused lack of continuing deposition that results in changing moisture and nutrient levels within existing sediments, such as on floodplains that no longer receive lateral or vertical accretion deposits because of levees, bank stabilization, and other channel engineering, and (iii) human-generated contaminants such as PCBs and pesticides that adsorb to fine sediment. Existing estimates of human alterations of river systems suggest that legacy sediments are ubiquitous. Only an estimated 2% of river miles in the United States are not affected by flow regulation that alters sediment transport, for example, and less than half of major river basins around the world are minimally altered by flow regulation. Combined with extensive but poorly documented reduction in floodplain sedimentation, as well as sediment contamination by diverse synthetic compounds, excess nutrients, and heavy metals, these national and global estimates suggest that legacy sediments now likely constitute a very abundant type of fluvial sediment. Because legacy sediments can alter river form and function for decades to centuries after the cessation of the human activity that created the legacy sediments, river management and restoration must be informed by accurate knowledge of the distribution and characteristics of legacy sediments. Geomorphologists can contribute understanding of sediment dynamics, including: the magnitude, frequency, and duration of flows that mobilize sediments with adsorbed contaminants; sites where erosion and deposition are most likely to occur under specified flow and sediment supply; residence time of sediments; and the influence of surface and subsurface water fluxes on sediment stability and geochemistry.

  4. Surface modification by subsurface pressure induced diffusion

    SciTech Connect

    Zimmermann, Claus G.

    2012-01-23

    Polycrystalline Ag, covered with a nm thin siloxane layer, was irradiated with ultraviolet light in vacuum at 500 K. Ag particles of different aspect ratios, 50-1000 nm in size, formed on the surface, including a small fraction of nanorods. Pressurized water vapor bubbles are created in the subsurface region by hydrogen radicals photo-chemically released by the siloxane layer. They provide the driving force for a diffusive material flux along grain boundaries to the surface. This mechanism was modeled and found to agree with the experimental timescale: approximately 300 h are required for a 1000 nm particle to form.

  5. Transport of subsurface bacteria in porous media

    SciTech Connect

    Bales, R.C.; Arnold, R.G.; Gerba, C.P.

    1995-02-01

    The primary objective of this study was to develop tools with which to measure the advective transport of microorganisms through porous media. These tools were then applied to investigate the sorptive properties of representative microorganisms that were selected at random from the DOE`s deep subsurface collection of bacterial, maintained at Florida State University. The transport screening procedure that arose from this study was also used to investigate biological factors that affect the transport/sorption of biocolloids during their movement through porous media with the bulk advective flow.

  6. Airborne Electromagnetic Mapping of Subsurface Permafrost

    NASA Astrophysics Data System (ADS)

    Abraham, J. D.; Minsley, B. J.; Cannia, J. C.; Smith, B. D.; Walvoord, M. A.; Voss, C. I.; Jorgenson, T. T.; Wylie, B. K.; Anderson, L.

    2011-12-01

    Concerns over the impacts of climate change have recently energized research on the potential impacts thawing permafrost may have on groundwater flow, infrastructure, forest health, ecosystems, energy production, CO2 release, and contaminant transport. There is typically little knowledge about subsurface permafrost distributions, such as thickness and where groundwater-surface-water connections may occur through taliks. In June of 2010, the U.S. Geological Survey undertook an airborne electromagnetic (AEM) survey in the area of Fort Yukon, Alaska in order to map the 3-D distribution of permafrost and provide information for the development of groundwater models within the Yukon River Basin. Prior to the development of these models, information on areas of groundwater-surface water interaction was extremely limited. Lithology determined from a borehole drilled in Fort Yukon in 1994 agrees well with the resistivity depth sections inferred from the airborne survey. In addition to lithology, there a thermal imprint appears on the subsurface resistivity values. In the upper 20-50 m, the sections show continuous areas of high electrical resistivity, consistent with alluvial gravel deposits that are likely frozen. At depth, unfrozen gravel deposits have intermediate-to-high resistivity; frozen silts have intermediate resistivity; and unfrozen silts have low resistivity. Under the Yukon River and lakes where the subsurface is not frozen, zones of moderate resistivity intermix with areas of low resistivity. The areas of loess hills on the margins of the Yukon Flats have very-high electrical resistivity, indicating higher ice content, and are associated with the some of the greatest thickness of permafrost in the survey area. This work provides the first look into the 3-D distribution of permafrost in the areas around Fort Yukon and is a demonstration of the application of AEM to permafrost mapping. The AEM survey provides unprecedented 3-D images of subsurface electrical

  7. Detection of microbes in the subsurface

    NASA Technical Reports Server (NTRS)

    White, David C.; Tunlid, Anders

    1989-01-01

    The search for evidence of microbial life in the deep subsurface of Earth has implications for the Mars Rover Sampling Return Missions program. If suitably protected environments can be found on Mars then the instrumentation to detect biomarkers could be used to examine the molecular details. Finding a lipid in Martian soil would represent possibly the simplest test for extant or extinct life. A device that could do a rapid extraction possibly using the supercritical fluid technology under development now with a detection of the carbon content would clearly indicate a sample to be returned.

  8. Instrumented Moles for Planetary Subsurface Regolith Studies

    NASA Astrophysics Data System (ADS)

    Richter, L. O.; Coste, P. A.; Grzesik, A.; Knollenberg, J.; Magnani, P.; Nadalini, R.; Re, E.; Romstedt, J.; Sohl, F.; Spohn, T.

    2006-12-01

    Soil-like materials, or regolith, on solar system objects provide a record of physical and/or chemical weathering processes on the object in question and as such possess significant scientific relevance for study by landed planetary missions. In the case of Mars, a complex interplay has been at work between impact gardening, aeolian as well as possibly fluvial processes. This resulted in regolith that is texturally as well as compositionally layered as hinted at by results from the Mars Exploration Rover (MER) missions which are capable of accessing shallow subsurface soils by wheel trenching. Significant subsurface soil access on Mars, i.e. to depths of a meter or more, remains to be accomplished on future missions. This has been one of the objectives of the unsuccessful Beagle 2 landed element of the ESA Mars Express mission having been equipped with the Planetary Underground Tool (PLUTO) subsurface soil sampling Mole system capable of self-penetration into regolith due to an internal electro-mechanical hammering mechanism. This lightweight device of less than 900 g mass was designed to repeatedly obtain and deliver to the lander regolith samples from depths down to 2 m which would have been analysed for organic matter and, specifically, organic carbon from potential extinct microbial activity. With funding from the ESA technology programme, an evolved Mole system - the Instrumented Mole System (IMS) - has now been developed to a readiness level of TRL 6. The IMS is to serve as a carrier for in situ instruments for measurements in planetary subsurface soils. This could complement or even eliminate the need to recover samples to the surface. The Engineering Model hardware having been developed within this effort is designed for accommodating a geophysical instrument package (Heat Flow and Physical Properties Package, HP3) that would be capable of measuring regolith physical properties and planetary heat flow. The chosen design encompasses a two-body Mole

  9. Parallel heater system for subsurface formations

    DOEpatents

    Harris, Christopher Kelvin; Karanikas, John Michael; Nguyen, Scott Vinh

    2011-10-25

    A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

  10. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1991-06-01

    This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

  11. Surface modification by subsurface pressure induced diffusion

    NASA Astrophysics Data System (ADS)

    Zimmermann, Claus G.

    2012-01-01

    Polycrystalline Ag, covered with a nm thin siloxane layer, was irradiated with ultraviolet light in vacuum at 500 K. Ag particles of different aspect ratios, 50-1000 nm in size, formed on the surface, including a small fraction of nanorods. Pressurized water vapor bubbles are created in the subsurface region by hydrogen radicals photo-chemically released by the siloxane layer. They provide the driving force for a diffusive material flux along grain boundaries to the surface. This mechanism was modeled and found to agree with the experimental timescale: approximately 300 h are required for a 1000 nm particle to form.

  12. Low temperature monitoring system for subsurface barriers

    DOEpatents

    Vinegar, Harold J.; McKinzie, II. Billy John

    2009-08-18

    A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

  13. Mineralogical Signatures in Electrically Coupled Marine Sediments

    NASA Astrophysics Data System (ADS)

    Bauermeister, A.; Gorby, Y. A.; Schramm, J.

    2014-12-01

    'Electric cable bacteria' are organisms of the family Desulfobulbaceaethat exhibit a novel method of electron transport. Cells form conductive filaments that function like electric wires, transferring electrons over distances of more than 1 cm from deep sulfidic sediments to oxygen or other electron acceptors near the soil/water interface. The rate of electron transfer across redox boundaries far exceeds that of diffusion limited processes and generates pH gradients that can significantly influence geochemical reactions, leading to the formation of distinct mineralogical profiles unlikely to be created by abiotic means. Electrically coupled sediments are characterized by carbonate and iron sulfide dissolution reactions occurring at depth and formation of carbonate and metal oxide crusts at the surface, exhibiting a reverse pattern compared to conventional sediment geochemistry. Our research seeks to address the following questions: How prevalent are electric cable bacteria in diverse environments? How do biogeochemical conditions such as ion concentration influence mineral formation? Do biogenic minerals participate in charge transfer? What is the importance of electric charge transfer in the subsurface or other low energy habitats? Can mineral banding patterns caused by cable bacteria activity be preserved in the geologic record? With this research we hope to further elucidate the impact of biologically-induced electric fields on the mineralogy of sediments.

  14. Crystal structure of laser-induced subsurface modifications in Si

    DOE PAGES

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; ...

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystalmore » structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.« less

  15. Crystal structure of laser-induced subsurface modifications in Si

    SciTech Connect

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in ’t Veld, A. J.

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystal structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.

  16. Optimal Electromagnetic (EM) Geophysical Techniques to Map the Concentration of Subsurface Ice and Adsorbed Water on Mars and the Moon

    NASA Astrophysics Data System (ADS)

    Stillman, D. E.; Grimm, R. E.

    2013-12-01

    Water ice is ubiquitous in our Solar System and is a probable target for planetary exploration. Mapping the lateral and vertical concentration of subsurface ice from or near the surface could determine the origin of lunar and martian ice and quantify a much-needed resource for human exploration. Determining subsurface ice concentration on Earth is not trivial and has been attempted previously with electrical resistivity tomography (ERT), ground penetrating radar (GPR), airborne EM (AEM), and nuclear magnetic resonance (NMR). These EM geophysical techniques do not actually detect ice, but rather the absence of unfrozen water. This causes a non-unique interpretation of frozen and dry subsurface sediments. This works well in the arctic because most locations are not dry. However, for planetary exploration, liquid water is exceedingly rare and subsurface mapping must discriminate between an ice-rich and a dry subsurface. Luckily, nature has provided a unique electrical signature of ice: its dielectric relaxation. The dielectric relaxation of ice creates a temperature and frequency dependence of the electrical properties and varies the relative dielectric permittivity from ~3.1 at radar frequencies to >100 at low frequencies. On Mars, sediments smaller than silt size can hold enough adsorbed unfrozen water to complicate the measurement. This is because the presence of absorbed water also creates frequency-dependent electrical properties. The dielectric relaxation of adsorbed water and ice can be separated as they have different shapes and frequency ranges as long as a spectrum spanning the two relaxations is measured. The volume concentration of ice and adsorbed water is a function of the strength of their relaxations. Therefore, we suggest that capacitively-coupled dielectric spectroscopy (a.k.a. spectral induced polarization or complex resistivity) can detect the concentration of both ice and adsorbed water in the subsurface. To prove this concept we have collected

  17. The subsurface origin of microbial life on the Earth.

    PubMed

    Trevors, J T

    2002-10-01

    Life on Earth can be divided into life on the surface made possible by photosynthesis and subsurface life with chemical energy as the driving force. An understanding of both environments is central to our understanding of the origin of life, the search for novel microbial species in the subsurface and for extraterrestrial life or life signatures. In this manuscript, the surface and subsurface worlds are examined with a focus on the origin or assembly of bacterial life.

  18. Evaluation of Subsurface Engineered Barriers at Waste Sites

    DTIC Science & Technology

    1998-08-01

    Evaluation of Subsurface Engineered Barriers at Waste Sites United States Environmental Protection Agency Office of Solid Waste and Emergency...of Subsurface Engineered Barriers at Waste Sites 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...1998 www.epa.gov clu-in.com EVALUATION OF SUBSURFACE ENGINEERED BARRIERS AT WASTE SITES i NOTICE This document was prepared for the U.S. Environmental

  19. Laterally spreading iron, humic-like dissolved organic matter and nutrients in cold, dense subsurface water of the Arctic Ocean

    PubMed Central

    Hioki, Nanako; Kuma, Kenshi; Morita, Yuichirou; Sasayama, Ryouhei; Ooki, Atsushi; Kondo, Yoshiko; Obata, Hajime; Nishioka, Jun; Yamashita, Youhei; Nishino, Shigeto; Kikuchi, Takashi; Aoyama, Michio

    2014-01-01

    The location and magnitude of oceanic iron sources remain uncertain owing to a scarcity of data, particularly in the Arctic Ocean. The formation of cold, dense water in the subsurface layer of the western Arctic Ocean is a key process in the lateral transport of iron, macronutrients, and other chemical constituents. Here, we present iron, humic-like fluorescent dissolved organic matter, and nutrient concentration data in waters above the continental slope and shelf and along two transects across the shelf–basin interface in the western Arctic Ocean. We detected high concentrations in shelf bottom waters and in a plume that extended in the subsurface cold dense water of the halocline layer in slope and basin regions. At σθ = 26.5, dissolved Fe, humic-like fluorescence intensity, and nutrient maxima coincided with N* minima (large negative values of N* indicate significant denitrification within shelf sediments). These results suggest that these constituents are supplied from the shelf sediments and then transported laterally to basin regions. Humic dissolved organic matter probably plays the most important role in the subsurface maxima and lateral transport of dissolved Fe in the halocline layer as natural Fe-binding organic ligand. PMID:25345398

  20. Distribution and geochemistry of contaminated subsurface waters in fissured volcanogenic bed rocks of the Lake Karachai Area, Chelyabinsk, Southern Urals

    SciTech Connect

    Solodov, I.N.; Belichkin, V.I.; Zotov, A.V.; Kochkin, B.T.; Drozhko, E.G.; Glagolev, A.V.; Skokov, A.N.

    1994-06-01

    The present investigation is devoted to the study of the distribution and geochemistry of contaminated subsurface waters, beneath the site of temporary storage of liquid radioactive waste known as Lake Karachai. For this purpose a method of hydrogeochemical logging (HGCL) together with standard hydrogeochemical and geophysical methods of uncased hole logging were used. The distribution of sodium nitrate brine plumes in the subsurface was determined by the physical and physico-chemical properties of these brines and by the petrochemical composition of enclosing rocks and the structural setting of the flow paths. The latter is represented by fractures and large faults in the bedrock of volcanogenic and volcanogenic-sedimentary rocks of intermediate-to-basic composition. The volcanogenic rocks are overlain in some places by a thin cover of unconsolidated sediments, i.e., by loams and relatively impermeable silts. Contaminated waters flow-in accordance with the eluvium bottom relief towards local areas of natural (Mishelyak and Techa rivers) and artificial (Novogomenskii water intake) discharge of subsurface waters. The large Mishelyak fault, southwest of Lake Karachai and under fluvial sediments of the Mishelyak, is assumed to significantly influence the flow pattern of contaminated waters, diverting them from an intake of drinking water.

  1. Atmospheric energy for subsurface life on Mars?

    PubMed Central

    Weiss, Benjamin P.; Yung, Yuk L.; Nealson, Kenneth H.

    2000-01-01

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H2 and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H2 and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H2O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life. PMID:10660689

  2. The subsurface of Pluto from submillimetre observations

    NASA Astrophysics Data System (ADS)

    Greaves, J. S.; Whitelaw, A. C. M.; Bendo, G. J.

    2015-04-01

    Surface areas on Pluto change in brightness and colour, at optical to infrared wavelengths, over time-scales as short as years. The subsurface contains a reservoir of frozen volatiles, but little is known about it because Pluto is out of reach for cm-radar. Here we present a 0.85 mm wavelength light curve of the Pluto system, from archival data taken in 1997 August with the SCUBA (Submillimetre Common-User Bolometer Array) camera on the James Clerk Maxwell Telescope (JCMT). This wavelength probes for the first time to just below the skin depth of thermal changes over Pluto's day. The light curve differs significantly from counterparts in the mid- to far-infrared, in a longitude range that is optically dark on Pluto's surface. An estimate from Herschel of the 0.5 mm flux in 2012 is comparable to the mean 0.45 mm flux from SCUBA in 1997, suggesting that layers centimetres below the surface have not undergone any gross temperature change. The longitudes that are relatively submillimetre-faint could have a different emissivity, perhaps with a subsurface layer richer in nitrogen or methane ices than at the surface. The Radio Science Experiment (REX) instrument on New Horizons may be able to constrain physical properties deeper down, as it looks back on Pluto's nightside after the 2015 July flyby.

  3. Phylogenetic relationships among subsurface microorganisms. Progress report

    SciTech Connect

    Nierzwicki-Bauer, S.A.

    1991-12-31

    This project involves the development of group specific 16S ribosomal RNA-targeted oligonucleotide hybridization probes for the rapid detection of specific types of subsurface organisms (e.g., groups of microbes that share certain physiological traits). Major accomplishments for the period of 6/91 to 12/1/91 are described. Nine new probes have been synthesized on the basis of published 16S rRNA sequence data from the Ribosomal Database Project. We have initiated rapid screening of many of the subsurface microbial isolates obtained from the P24 borehole at the Savannah River Site. To date, we have screened approximately 50% of the isolates from P24. We have optimized our {und in situ} hybridization technique, and have developed a cell blot hybridization technique to screen 96 samples on a single blot. This is much faster than reading 96 individual slides. Preliminary experiments have been carried out which indicate specific nutrients can be used to amplify rRNA only in those organisms capable of metabolizing those nutrients. 1 tab., 2 figs.

  4. Human utilization of subsurface extraterrestrial environments.

    PubMed

    Boston, P J; Frederick, R D; Welch, S M; Werker, J; Meyer, T R; Sprungman, B; Hildreth-Werker, V; Thompson, S L; Murphy, D L

    2003-06-01

    Caves have been used in the ancient past as shelter or habitat by many organisms (including humans). Since antiquity, humans have explored caves for the minerals they contain and sometimes for ceremonial purposes. Over the past century, caves have become the target of increasing exploration, scientific research, and recreation. The use of caves on extraterrestrial bodies for human habitation has been suggested by several investigators. Lunar lava tube bases received early attention because lava tubes were clearly visible in lunar images from the Apollo Era. More recently, Mars Observer Camera data has shown us clear evidence of large tubes visible in a number of volcanic regions on Mars. The budding field of cave geomicrobiology has direct application to questions about subsurface life on other planets. Caves contain many unusual organisms making their living from unlikely materials like manganese, iron, and sulfur. This makes caves and other subsurface habitats prime targets for astrobiological missions to Mars and possibly other bodies. We present the results of a completed Phase I and on-going Phase II NASA Institute for Advanced Concepts (NIAC) study that intensively examines the possibilities of using extraterrestrial caves as both a resource for human explorers and as a highly promising scientific target for both robotic and future human missions to Mars and beyond.

  5. Atmospheric energy for subsurface life on Mars?

    NASA Technical Reports Server (NTRS)

    Weiss, B. P.; Yung, Y. L.; Nealson, K. H.

    2000-01-01

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H(2) and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H(2) and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H(2)O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

  6. Atmospheric energy for subsurface life on Mars?

    PubMed

    Weiss, B P; Yung, Y L; Nealson, K H

    2000-02-15

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H(2) and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H(2) and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H(2)O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

  7. Method and apparatus for subsurface exploration

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian (Inventor)

    2002-01-01

    A subsurface explorer (SSX) for exploring beneath the terrestrial surface of planetary bodies such as the Earth, Mars, or comets. This exploration activity utilizes appropriate sensors and instrument to evaluate the composition, structure, mineralogy and possibly biology of the subsurface medium, as well as perhaps the ability to return samples of that medium back to the surface. The vehicle comprises an elongated skin or body having a front end and a rear end, with a nose piece at the front end for imparting force to composition material of the planetary body. Force is provided by a hammer mechanism to the back side of a nose piece from within the body of the vehicle. In the preferred embodiment, a motor spins an intermediate shaft having two non-uniform threads along with a hammer which engages these threads with two conical rollers. A brake assembly halts the rotation of the intermediate shaft, causing the conical roller to spin down the non-uniform thread to rapidly and efficiently convert the rotational kinetic energy of the hammer into translational energy.

  8. Improving subsurface hydrology in Earth System Models

    NASA Astrophysics Data System (ADS)

    Volk, J. M.; Clark, M. P.; Swenson, S. C.; Lawrence, D. M.; Tyler, S. W.

    2015-12-01

    Hydrologic processes that govern storage and transport of soil water and groundwater can have strong dynamic relationships with biogeochemical and atmospheric processes. This understanding has lead to a push to improve subsurface hydrologic parametrization in Earth System Models. Here we present results related to improving the implementation of soil moisture distribution, groundwater recharge/discharge, and subsurface drainage in the Community Land Model (CLM) which is the land surface model in the Community Earth System Model. First we identified geo-climatically different locations around the world to develop test cases. For each case we compare the vertical soil moisture distribution from the different implementations of 1D Richards equation, considering the boundary conditions, the treatment of the groundwater sink term, the vertical discretization, and the time stepping schemes. Generally, large errors in the hydrologic mass balance within the soil column occur when there is a large vertical gradient in soil moisture or when there is a shallow water table within a soil column. We then test the sensitivity of the algorithmic parameters that control temporal discretization and error tolerance of the adaptive time-stepping scheme to help optimize its computational efficiency. In addition, we vary the spatial discretization of soil layers (i.e. quantity of layers and their thicknesses) to better understand the sensitivity of vertical discretization of soil columns on soil moisture variability in ESMs. We present multivariate and multi-scale evaluation for the different model options and suggest ways to move forward with future model improvements.

  9. Subsurface Defect Detection in FRP Composites Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Halabe, U. B.; Vasudevan, A.; GangaRao, H. V. S.; Klinkhachorn, P.; Lonkar, G.

    2005-04-01

    This paper demonstrates the use of digital infrared thermography to detect subsurface defects such as debonds and delaminations in Fiber Reinforced Polymer (FRP) bridge decks. Simulated sub-surface debonds and delaminations were inserted between the wearing surface and the underlying FRP deck specimens. The infrared thermography technique was used to detect these embedded subsurface defects. The use of various cooling and heating methods, including solar radiation, was explored. Surface temperature-time curves were established for different types and sizes of subsurface defects.

  10. Modeling subsurface stormflow initiation in low-relief landscapes

    NASA Astrophysics Data System (ADS)

    Hopp, Luisa; Vaché, Kellie B.; Rhett Jackson, C.; McDonnell, Jeffrey J.

    2015-04-01

    Shallow lateral subsurface flow as a runoff generating mechanism at the hillslope scale has mostly been studied in steeper terrain with typical hillside angles of 10 - 45 degrees. These studies have shown that subsurface stormflow is often initiated at the interface between a permeable upper soil layer and a lower conductivity impeding layer, e.g. a B horizon or bedrock. Many studies have identified thresholds of event size and soil moisture states that need to be exceeded before subsurface stormflow is initiated. However, subsurface stormflow generation on low-relief hillslopes has been much less studied. Here we present a modeling study that investigates the initiation of subsurface stormflow on low-relief hillslopes in the Upper Coastal Plain of South Carolina, USA. Hillslopes in this region typically have slope angles of 2-5 degrees. Topsoils are sandy, underlain by a low-conductivity sandy clay loam Bt horizon. Subsurface stormflow has only been intercepted occasionally in a 120 m long trench, and often subsurface flow was not well correlated with stream signals, suggesting a disconnect between subsurface flow on the hillslopes and stream flow. We therefore used a hydrologic model to better understand which conditions promote the initiation of subsurface flow in this landscape, addressing following questions: Is there a threshold event size and soil moisture state for producing lateral subsurface flow? What role does the spatial pattern of depth to the impeding clay layer play for subsurface stormflow dynamics? We reproduced a section of a hillslope, for which high-resolution topographic data and depth to clay measurements were available, in the hydrologic model HYDRUS-3D. Soil hydraulic parameters were based on experimentally-derived data. The threshold analysis was first performed using hourly climate data records for 2009-2010 from the study site to drive the simulation. For this period also trench measurements of subsurface flow were available. In addition

  11. Vertical distribution of benthic infauna in continental slope sediments off Cape Lookout, North Carolina

    NASA Astrophysics Data System (ADS)

    Blake, James A.

    The vertical distribution of 30 species of benthic infauna from continental slope (583-3000 m) sediments off Cape Lookout, North Carolina was closely correlated with feeding types. Carnivores, omnivores, filter feeders, and surface deposit feeders were mostly concentrated in the upper 0-2 cm of the cores. The depth distribution of subsurface deposit feeders was more variable, even among related taxa.

  12. Effect of alternative surface inlet designs on sediment and phosphorus drainage losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

  13. Microbial effects on the release and attenuation of arsenic in the shallow subsurface of a natural geochemical anomaly.

    PubMed

    Drahota, Petr; Falteisek, Lukáš; Redlich, Aleš; Rohovec, Jan; Matoušek, Tomáš; Cepička, Ivan

    2013-09-01

    Critical factors leading to arsenic release and attenuation from the shallow subsurface were studied with multidisciplinary approach in the natural gold-arsenic geochemical anomaly at Mokrsko (Czech Republic). The results show that microbial reduction promotes arsenic release from Fe(III) (hydr)oxides and Fe(III) arsenates, thereby enhancing dissolved arsenic in the shallow groundwater at average concentration of 7.76 mg/L. In the organic-rich aggregates and wood particles, however, microbial sulfate reduction triggers the formation of realgar deposits, leading to accumulation of As in the distinct organic-rich patches of the shallow subsurface. We conclude that precipitation of realgar in the shallow subsurface of soil/sediment depends on specific and non-trivial combination of water and rock chemistry, microbial community composition and spatial organisation of the subsurface zone, where speciation in saturated environments varied on a centimeter scale from reduced (decomposed wood, H2S and realgar present) to oxidized (goethite and arsenate minerals are present).

  14. Microbially Induced Calcite Precipitation for Subsurface Immobilization of Contaminants

    NASA Astrophysics Data System (ADS)

    Smith, R. W.; Fujita, Y.; Ginn, T. R.; Hubbard, S. S.; Dafflon, B.; Delwiche, M.; Gebrehiwet, T.; Henriksen, J. R.; Peterson, J.; Taylor, J. L.

    2011-12-01

    Subsurface radionuclide and metal contaminants throughout the U.S. Department of Energy (DOE) complex pose one of the greatest challenges for long-term stewardship. One promising stabilization mechanism for divalent trace ions, such as the short-lived radionuclide 90Sr, is co-precipitation in calcite. We have found that calcite precipitation and co-precipitation of Sr can be accelerated by the activity of urea hydrolyzing microorganisms, that higher calcite precipitation rates can result in increased Sr partitioning, and that nutrient additions can stimulate ureolytic activity. To extend our understanding of microbially induced calcite precipitation (MICP) in an aquifer setting a continuous recirculation field experiment evaluating MICP was conducted at the Integrated Field Research Challenge (IFRC) site located at Rifle, CO. In this experiment, groundwater extracted from an onsite well was amended with urea (total mass of 42.5 kg) and molasses (a carbon and electron donor) and re-injected into a well approximately 4 meters up-gradient for a period of 12 days followed by 10 months of groundwater sampling and monitoring. Crosshole radar and electrical tomographic data were collected prior, during, and after the MICP treatment. The urea and molasses treatment resulted in an enhanced population of sediment associated urea hydrolyzing organisms as evidenced by increases in the number of ureC gene copies, increases in 14C urea hydrolysis rates, and long-term observations of ammonium (a urea hydrolysis product) in the injection, extraction and down gradient monitoring wells. Permeability changes and increases in the calcite saturation indexes in the well field suggest that mineral precipitation has occurred; ongoing analysis of field samples seeks to confirm this. Changes in dielectric constant and electrical conductivity were used to interpret the spatiotemporal distribution of the injectate and subsequent calcite precipitation. Modeling activities are underway to

  15. Microbial Activity in the Subseafloor Sediments of ODP Leg 201

    NASA Astrophysics Data System (ADS)

    D'Honst, S.; Joergensen, B. B.; Blake, R.; Dickens, G.; Hinrichs, K.; Holm, N.; Mitterer, R.; Spivack, A.

    2002-12-01

    Ocean Drilling Program Leg 201 was the first ocean drilling expedition dedicated to the study of life deep beneath the seafloor. Its equatorial Pacific and Peru Margin sites were selected to represent the general range of subsurface environments that exists in marine sediments throughout most of the world's oceans. In water depths as great as 5300 meters and as shallow as 150 meters, the expedition drilled up to 420 meters into oceanic sediments and the underlying basaltic crust. The sediments ranged in temperature from 1° C to 25° C and in age from 0 to almost 40 million years. Leg 201 scientists found biogeochemical evidence of metabolic activity throughout the sediment column at every site. This activity is supported at all sites by the diffusion of sulfate down from the overlying ocean, as well as by the dissolution of iron- and manganese-bearing minerals. At the open ocean sites, metabolic activity deep beneath the seafloor is also supported by the transport of sulfate, nitrate and oxygen from water circulating through the underlying basaltic crust. At both the open ocean sites and the Peru margin sites, multiple metabolic activities (sulfate reduction, iron reduction, manganese reduction and methanogenesis) co-occur. Chemical flux estimates suggest that sulfate is generally the principal terminal electron acceptor in these subseafloor sediments. However, at the open ocean sites with the lowest rates of microbial respiration, manganese may rival sulfate as a terminal electron acceptor. The recovered sediments and fluids are being studied further to document the controls on rates of subsurface activity, the influence of past oceanographic conditions on current activity in deeply buried sediments, and the effects of subseafloor biogeochemical processes on Earth's surface world.

  16. Shallow subsurface stratigraphy and alluvial architecture of the Kosi and Gandak megafans in the Himalayan foreland basin, India

    NASA Astrophysics Data System (ADS)

    Sinha, Rajiv; Ahmad, Jawed; Gaurav, Kumar; Morin, Guillaume

    2014-03-01

    The Kosi and the Gandak are two major Himalayan tributaries of the Ganga River in the north Bihar plains India. With a large hinterland in the Nepal Himalaya, both these rivers have generated megafans in the plains over the Quaternary time scale. Both these rivers are known to be highly dynamic and sediment-charged. A few conceptual models and limited field data suggested that these megafans have produced thick sand sheets over Late Quaternary period but these ideas have remained speculative and there is no data on the size and dimension of these sand bodies. This paper attempts to reconstruct the subsurface stratigraphy and alluvial architecture for the upper ~ 100 m of the megafans based on electrical resistivity soundings, borehole data and drill cores. Alluvial architecture of the Kosi megafan shows significant variability from proximal to medial parts of the fan in terms of sediment grain size and layer thicknesses. While the medial part shows ~ 20-30 m thick medium to coarse sand sheets which are laterally stacked, the proximal part of the fan has a dominantly gravel unit below ~ 15 m depth that is underlain and overlain by medium to coarse sand units. Further, the medial fan also shows significant vertical and lateral variability in alluvial stratigraphy. The near-surface (< 20 m depth) deposits from the Kosi megafan have pockets of clay and silt within large amalgamated sand bodies whereas the shallow sub-surface (50-100 m depth) sediments are largely sandy and devoid of clay and silt pockets. Alluvial architecture of the Gandak megafan shows two major lithounits; the upper fan succession has a higher stacking density of smaller sand bodies perhaps reflecting the migratory behavior of the river whereas the lower succession shows narrow but thick sand fills reflecting incised channels. The western part of the Gandak megafan has more abundant sand bodies compared to the eastern side of the river along both transects. There are no significant differences

  17. The DOE Subsurface (SubTER) Initiative: Revolutionizing Responsible use of the Subsurface for Energy Production and Storage

    NASA Astrophysics Data System (ADS)

    Hubbard, S. S.; Walck, M. C.; Blankenship, D.; Bonneville, A.; Bromhal, G. S.; Daley, T. M.; Pawar, R.; Polsky, Y.; Mattson, E.; Mellors, R. J.

    2015-12-01

    The subsurface supplies more than 80% of the U.S.'s total energy needs through geothermal and hydrocarbon strategies and also provides vast potential for safe storage of CO2 and disposal of nuclear waste. Responsible and efficient use of the subsurface poses many challenges, many of which require the capability to monitor and manipulate sub-surface stress, fractures, and fluid flow at all scales. Adaptive control of subsurface fractures and flow is a multi-disciplinary challenge that, if achieved, has the potential to transform all subsurface energy strategies. As part of the U.S. Department of Energy's SubTER (Subsurface Technology and Engineering Research development and demonstration) initiative, a multi-National Laboratory team is developing next-generation approaches that will allow for adaptive control of subsurface fractures and flow. SubTER has identified an initial suite of technical thrust areas to focus work, and has initiated a number of small projects. This presentation will describe early progress associated with the SubTER technical topic areas of wellbore integrity, subsurface stress and induced seismicity, permeability manipulation and new subsurface signals. It will also describe SubTER plans, and provide a venue to solicit suggestions and discuss potential partnerships associated with future research directions.

  18. Tropical Indian Ocean subsurface temperature variability and the forcing mechanisms

    NASA Astrophysics Data System (ADS)

    Sayantani, Ojha; Gnanaseelan, C.

    2015-05-01

    The first two leading modes of interannual variability of sea surface temperature in the Tropical Indian Ocean (TIO) are governed by El Niño Southern Oscillation and Indian Ocean Dipole (IOD) respectively. TIO subsurface however does not co-vary with the surface. The patterns of the first mode of TIO subsurface temperature variability and their vertical structure are found to closely resemble the patterns of IOD and El Niño co-occurrence years. These co-occurrence years are characterized by a north-south subsurface dipole rather than a conventional IOD forced east-west dipole. This subsurface dipole is forced by wind stress curl anomalies, driven mainly by meridional shear in the zonal wind anomalies. A new subsurface dipole index (SDI) has been defined in this study to quantify the intensity of the north-south dipole mode. The SDI peaks during December to February (DJF), a season after the dipole mode index peaks. It is found that this subsurface north-south dipole is a manifestation of the internal mode of variability of the Indian Ocean forced by IOD but modulated by Pacific forcing. The seasonal evolution of thermocline, subsurface temperature and the corresponding leading modes of variability further support this hypothesis. Positive wind stress curl anomalies in the south and negative wind stress curl anomalies in the north of 5°S force (or intensify) downwelling and upwelling waves respectively during DJF. These waves induce strong subsurface warming in the south and cooling in the north (especially during DJF) and assist the formation and/or maintenance of the north-south subsurface dipole. A thick barrier layer forms in the southern TIO, supporting the long persistence of anomalous subsurface warming. To the best of our knowledge the existence of such north-south subsurface dipole in TIO is being reported for the first time.

  19. Plutonium Contamination Issues in Hanford Soils and Sediments: Discharges from the Z-Plant (PFP) Complex

    SciTech Connect

    Felmy, Andrew R.; Cantrell, Kirk J.; Conradson, Steven D.

    2010-08-23

    Beginning in 1945, weapons production activities at the Hanford Nuclear Reservation resulted in the discharge of large quantities of Pu and other transuranic elements to the subsurface. The vast majority of the transuranics were disposed in the Hanford central plateau (200 areas) predominately associated with activities at the Z-Plant (Plutonium Finishing Plant) complex. In the past the Pu and Am migrated deep into the subsurface at certain locations, although the Pu and other transuranics are not currently being detected in significant concentration in any associated groundwaters. Evaluation of the chemical form of the transuranics in the subsurface along with determining the mechanism(s) of the past subsurface migration is important in establishing strategies for long-term site management practices. Unfortunately, the chemical form of the transuranics in the deep subsurface sediments and the past mechanism of vertical migration remain largely unknown. This paper present a summary of the different waste types and locations where transuranics were disposed, the factors that could have lead to subsurface migration via different transport vectors, the information currently available on the chemical form of Pu in the subsurface, and a summary of current research needs.

  20. Superfund: Contaminated Sediments

    EPA Pesticide Factsheets

    Contaminated sediments are a significant environmental problem and contribute to the over 3,200 fish consumption advisories nationwide. The Superfund program cleans up sediment sites that present an unacceptable risk to human health or the environment.

  1. Indicators: Sediment Enzymes

    EPA Pesticide Factsheets

    Sediment enzymes are proteins that are produced by microorganisms living in the sediment or soil. They are indicators of key ecosystem processes and can help determine which nutrients are affecting the biological community of a waterbody.

  2. Sediment Toxicity Identification Evaluation

    EPA Science Inventory

    Approach combining chemical manipulations and aquatic toxicity testing, generally with whole organisms, to systematically characterize, identify and confirm toxic substances causing toxicity in whole sediments and sediment interstitial waters. The approach is divided into thre...

  3. Contaminated Sediment Core Profiling

    EPA Science Inventory

    Evaluating the environmental risk of sites containing contaminated sediments often poses major challenges due in part to the absence of detailed information available for a given location. Sediment core profiling is often utilized during preliminary environmental investigations ...

  4. Viral activities and life cycles in deep subseafloor sediments.

    PubMed

    Engelhardt, Tim; Orsi, William D; Jørgensen, Bo Barker

    2015-12-01

    Viruses are highly abundant in marine subsurface sediments and can even exceed the number of prokaryotes. However, their activity and quantitative impact on microbial populations are still poorly understood. Here, we use gene expression data from published continental margin subseafloor metatranscriptomes to qualitatively assess viral diversity and activity in sediments up to 159 metres below seafloor (mbsf). Mining of the metatranscriptomic data revealed 4651 representative viral homologues (RVHs), representing 2.2% of all metatranscriptome sequence reads, which have close translated homology (average 77%, range 60-97% amino acid identity) to viral proteins. Archaea-infecting RVHs are exclusively detected in the upper 30 mbsf, whereas RVHs for filamentous inoviruses predominate in the deepest sediment layers. RVHs indicative of lysogenic phage-host interactions and lytic activity, notably cell lysis, are detected at all analysed depths and suggest a dynamic virus-host association in the marine deep biosphere studied here. Ongoing lytic viral activity is further indicated by the expression of clustered, regularly interspaced, short palindromic repeat-associated cascade genes involved in cellular defence against viral attacks. The data indicate the activity of viruses in subsurface sediment of the Peruvian margin and suggest that viruses indeed cause cell mortality and may play an important role in the turnover of subseafloor microbial biomass.

  5. Iron monosulfide accumulation and pyrite formation in eutrophic estuarine sediments

    NASA Astrophysics Data System (ADS)

    Kraal, Peter; Burton, Edward D.; Bush, Richard T.

    2013-12-01

    This study investigates iron (Fe) and sulfur (S) cycling in sediments from the eutrophic Peel-Harvey Estuary in Western Australia, which is subject to localized accumulation of strongly reducing, organic- and sulfide-rich sediments. Sedimentary iron was mostly present in highly reactive form (on average 73% of total Fe) and showed extensive sulfidization even in surface sediments, despite being overlain by a well-mixed oxygenated water column. This indicates that, under eutrophic marine conditions, Fe sulfidization may be driven by reductive processes in the sediment without requiring oxygen depletion in the overlying waters. Strong enrichments in iron monosulfide (FeS > 300 μmol g-1) were observed in fine-grained sediment intervals up to 45 cm depth. This metastable Fe sulfide is commonly restricted to thin subsurface sediment intervals, below which pyrite (FeS2) dominates. Our findings suggest inhibition of the dissolution-precipitation processes that replace FeS with FeS2 in sediments. Rates of pyrite formation based on the FeS2 profiles were much lower than those predicted by applying commonly used kinetic equations for pyrite formation. Dissolved H2S was present at millimolar levels throughout the investigated sediment profiles. This may indicate that (i) pyrite formation via reaction between dissolved Fe (including Fe clusters) and H2S was limited by low availability of dissolved Fe or (ii) reaction kinetics of pyrite formation via the H2S pathway may be relatively slow in natural reducing sediments. We propose that rapid burial of the FeS under anoxic conditions in these organic-rich reducing sediments minimizes the potential for pyrite formation, possibly by preventing dissolution of FeS or by limiting the availability of oxidized sulfur species that are required for pyrite formation via the polysulfide pathway.

  6. Air-water flow in subsurface systems

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  7. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, James G.; Daily, William D.

    1994-01-01

    A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  8. Repository Subsurface Preliminary Fire Hazard Analysis

    SciTech Connect

    Richard C. Logan

    2001-07-30

    This fire hazard analysis identifies preliminary design and operations features, fire, and explosion hazards, and provides a reasonable basis to establish the design requirements of fire protection systems during development and emplacement phases of the subsurface repository. This document follows the Technical Work Plan (TWP) (CRWMS M&O 2001c) which was prepared in accordance with AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities''; Attachment 4 of AP-ESH-008, ''Hazards Analysis System''; and AP-3.11Q, ''Technical Reports''. The objective of this report is to establish the requirements that provide for facility nuclear safety and a proper level of personnel safety and property protection from the effects of fire and the adverse effects of fire-extinguishing agents.

  9. Solving subsurface structural problems using a computer

    SciTech Connect

    Witte, D.M. )

    1987-02-01

    Until recently, the solution of subsurface structural problems has required a combination of graphical construction, trigonometry, time, and patience. Recent advances in software available for both mainframe and microcomputers now reduce the time and potential error of these calculations by an order of magnitude. Software for analysis of deviated wells, three point problems, apparent dip, apparent thickness, and the intersection of two planes, as well as the plotting and interpretation of these data can be used to allow timely and accurate exploration or operational decisions. The available computer software provides a set of utilities, or tools, rather than a comprehensive, intelligent system. The burden for selection of appropriate techniques, computation methods, and interpretations still lies with the explorationist user.

  10. Joint inversion for mapping subsurface hydrologicalparameters

    SciTech Connect

    Tseng, Hung-Wen; Lee, Ki Ha

    2001-03-07

    Using electromagnetic (EM) and seismic travel time data and a least-square criteria, a two-dimensional joint inversion algorithm is under development to assess the feasibility of directly mapping subsurface hydrological properties in a crosswell setup. A simplified Archie's law combined with the time average equation relates the magnetic fields and seismic travel time to two hydrological parameters; rock porosity and pore fluid electrical conductivity. For simplicity, the hydrological parameter distributions are assumed to be two-dimensional. Preliminary results show that joint inversion does have better resolving power for the interpretation than using the EM method alone. Various inversion scenarios have been tested, and it has been found that alternately perturbing just one of the two parameters at each iteration gives the best data fit.

  11. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, J.G.; Daily, W.D.

    1994-07-05

    A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  12. Microfluidic adhesion induced by subsurface microstructures.

    PubMed

    Majumder, Abhijit; Ghatak, Animangsu; Sharma, Ashutosh

    2007-10-12

    Natural adhesives in the feet of different arthropods and vertebrates show strong adhesion as well as excellent reusability. Whereas the hierarchical structures on the surface are known to have a substantial effect on adhesion, the role of subsurface structures such as the network of microchannels has not been studied. Inspired by these bioadhesives, we generated elastomeric layers with embedded air- or oil-filled microchannels. These adhesives showed remarkable enhancement of adhesion ( approximately 30 times), which results from the crack-arresting properties of the microchannels, together with the surface stresses caused by the capillary force. The importance of the thickness of the adhesive layer, channel diameter, interchannel spacing, and vertical position within the adhesive has been examined for developing an optimal design of this microfluidic adhesive.

  13. Microwave radiometer for subsurface temperature measurement

    NASA Technical Reports Server (NTRS)

    Porter, R. A.; Bechis, K. P.

    1976-01-01

    A UHF radiometer, operating at a frequency of 800 MHz, was modified to provide an integral, three frequency voltage standing wave ratio (VSWR) circuit in the radio frequency (RF) head. The VSWR circuit provides readings of power transmission at the antenna-material interface with an accuracy of plus or minus 5 percent. The power transmission readings are numerically equal to the emissivity of the material under observation. Knowledge of material emissivity is useful in the interpretation of subsurface apparent temperatures obtained on phantom models of biological tissue. The emissivities of phantom models consisting of lean beefsteak were found to lie in the range 0.623 to 0.779, depending on moisture content. Radiometric measurements performed on instrumented phantoms showed that the radiometer was capable of sensing small temperature changes occurring at depths of at least 19 to 30 mm. This is consistent with previously generated data which showed that the radiometer could sense temperatures at a depth of 38 mm.

  14. Armored Enzyme Nanoparticles for Remediation of Subsurface

    SciTech Connect

    Grate, Jay W.

    2005-09-01

    The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides; or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation.

  15. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1992-06-01

    A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least FAB making thisthe most common physiological type of anaerobic bacteria present in the deep subsurface at these two sites. INEL core samples are characterized by isolates of both FAB and OAB. No isolates of acetogenic, methanogenic, or sulfate reducing bacteria were obtained. Yakima core samples are characterized by a marked predominance of FAB in comparison to OAB. In addition, isolates of acetogenic, methanogenic, and sulfate reducing bacteria were obtained. The Yakima site has the potential for complete anaerobic mineralization of organic compounds whereas this potential appears to be lacking at INEL.

  16. Letter report: Ari Patrinos -- Subsurface bioremediation

    SciTech Connect

    Happer, W.; MacDonald, G.J.; Ruderman, M.A.; Treiman, S.B.

    1995-07-26

    During the past summer, the authors had the opportunity to examine aspects of the remediation program of the Department of Energy (DOE). The most important conclusion that they have come to is that there is an urgent need to mount a comprehensive research program in remediation. It is also clear to them that DOE does not have the funding to carry out a program on the scale that is required. On the other hand, Environmental Management could very well fund such activities. They would hope that in the future there would be close collaboration between Environmental Management and Energy Research in putting together a comprehensive and well thought-out research program. Here, the authors comment on one aspect of remediation: subsurface bioremediation.

  17. Locating subsurface gravel with thermal imagery

    NASA Technical Reports Server (NTRS)

    Scholen, Douglas E.; Clerke, William H.; Luepke, Douglas E.

    1986-01-01

    A method was discussed for using 6 band thermal imagery to locate subsurface gravel deposits in vegetated areas. Geologic history is reviewed to select potential areas of study. An overflight was made using a thermal scanner. The data were processed with a computerized system to delineate areas showing a quartz signature radiated by a gravel deposit. The method was developed during a search for gravel on National Forest land in Louisiana. Processed data from thermal imagery was compared with known gravel deposits and exploratory drill hole logs. A high correlation was noted for a wide range of deposits, from commercial pits to trace deposits only a foot thick. Overburden at these sites varied from zero to sixty feet, near the maximum annual penetration by the thermal wave. It was concluded that the method can be used to locate buried gravel deposits and that more time and effort are needed to verify the usefulness for developing gravel pits adjacent to proposed construction sites.

  18. Distribution of surface deposits in the Gijón urban subsurface (NW Spain)

    NASA Astrophysics Data System (ADS)

    López-Fernández, Carlos; Pando, Luis; María Díaz-Díaz, Luis; Arias, Daniel; Flor-Blanco, Germán

    2016-04-01

    Gijón is the second most populous city (278.285 inhabitants in 2015) of the Spanish north coast. The urban subsurface is mostly formed (≈80%) by Quaternary sediments which exceeds 20 meters of thickness when cover the Jurassic carbonate basement (Gijón Formation). This work has allowed to know the spatial distribution of the different types of sediments in urban area. To do this, a GIS database was developed that contains data from more than 450 geotechnical reports. Information provided by fieldwork and the exploration of excavation works in progress throughout the city was also incorporated. Currently, the geodatabase developed comprises more than 1,400 site investigation points: boreholes, dynamic probing and trial pits. This has been supplemented with hundreds on-site and laboratory tests carried out on core samples of soils and rocks, performed following renowned testing standards. Quaternary formations, largely concealed below man-made fills, set up two main areas composed by granular and cohesive soils: the littoral zone at the northern urban perimeter and the continental zone at the southern sector. The first one, fluvial-marine deposits, consist of sandy sediments related to beach/dune systems and marsh deposits, with gravels, organogenic mud and layers of Holocene peat. The southern area is composed by residual clays -silt and coarse-grained soils to a lesser extent- linked to the dissolution of the Mesozoic substrate. Associated with these two types of deposits, two main aquifers can be differentiated. The thickness of the man-made deposits, fluvial-marine sediments and residual deposits was determined in this work. Thus, a 3-d model of Gijón subsurface at urban scale was obtained. A map of the Jurassic bedrock bedrock was also produced. Building construction works may be affected by the geotechnical behavior of the Quaternary deposits and the saturation of granular sediments., This is because the shallowness of the water table, the usual low

  19. Interstitial brines in playa sediments

    USGS Publications Warehouse

    Jones, B.F.; Van Denburgh, A.S.; Truesdell, A.H.; Rettig, S.L.

    1969-01-01

    Study of several closed drainages in the Great Basin has shown that the interstitial solutions of shallow, fine-grained playa deposits store a large quantity of dissolved solids and are often more concentrated than associated lakes and ponds, except in peripheral zones of stream or ground-water inflow. These interstitial fluids, when compared with local runoff, impoundments, or spring waters, commonly have a distinctive ionic composition which sometimes cannot be explained by either simple mixing of surface and subsurface inflow or by evaporative concentration. At Abert Lake, Oregon, the interstitial solute concentrations increased with depth to values as much as five times greater than the lake, except where springs indicate significant ground-water input. Where Na+, Cl, and CO2 species constitute more than 90% of the solutes, Na+ Cl- ratios in the lake water are lower than in interstitial solutions of bottom cores and higher than in playa fluids. At the same time, Na+ K+ ratios are highest in the fluids of lake bottom muds and lowest in playa interstitials. In deeper playa profiles, interstitial Na+ Cl- tended to decrease with depth (5 ft. maximum). In the Abert Lake area, as in other parts of the western Great Basin, Na+ Cl- ratios are indicative of total CO2 in solution and the effects of organic decay in surficial sediments. These ratios, coupled with data on silica and bulk density, show that higher PCO2 accompanying decay promotes silicate dissolution and hydrogen ion exchange, stripping alkalis from sediment which had preferentially adsorbed K+ when entering the lake. On subsequent loss of pore fluid in the playa regime, silica initially released to solution in the lake environment is readsorbed on dissolution products. ?? 1969.

  20. Subsurface Controls on Habitability of Hydrothermal Waters

    NASA Astrophysics Data System (ADS)

    Fristad, K. E.; Som, S. M.; Hoehler, T. M.

    2014-12-01

    Liquid water alone does not make an environment habitable. Environmental settings dominated by water-rock reactions such as in hydrothermal vents and springs are natural targets for astrobiological investigation of waterworlds because the rich geochemical diversity at these locales provides abundant energy in solvent to support microbial life. Hydrogen oxidizers are of particular interest because H2-based metabolisms are widespread and deeply rooted throughout the phylogenetic tree of life, implying they may have emerged extremely early in the evolution, and possibly even the origin, of life on Earth and potentially any other rocky bodies bearing liquid water. Dihydrogen (H2) can be lithogenically produced by the hydrolytic oxidation of the ferrous iron component in Fe-bearing minerals as well as by radiolytic cleavage of water by α, β, or γ radiation produced during the decay of radioactive isotopes. Lithogenic H2 production mechanisms operate across a range of rock types, but the concentration of dissolved H2 available to life is controlled by a number of subsurface factors such as surface geometry, water to rock ratio, production rate, and fluid flux. These factors are often controlled by the larger geologic and structural context of a particular site. We present results of an ongoing project that surveys H2 concentrations from terrestrial hydrothermal waters in diverse chemical and physical settings. Aqueous H2 concentrations and potential subsurface controls are presented for sites across the western U.S. including Yellowstone National Park, Lassen Volcanic National Park, and Iceland. In coordination with field data, we also investigate the habitability of various sites numerically by coupling a geochemical model of water-rock interaction with that of single-cell methanogenesis and compute a habitability index for the given environment. In particular, we investigate the control that temperature, rock composition, water composition, and water to rock ratio

  1. Imaging the Subsurface with Upgoing Muons

    NASA Astrophysics Data System (ADS)

    Bonal, N.; Preston, L. A.; Schwellenbach, D.; Dreesen, W.; Green, A.

    2014-12-01

    We assess the feasibility of imaging the subsurface using upgoing muons. Traditional muon imaging focuses on more-prevalent downgoing muons. Muons are subatomic particles capable of penetrating the earth's crust several kilometers. Downgoing muons have been used to image the Pyramid of Khafre of Giza, various volcanoes, and smaller targets like cargo. Unfortunately, utilizing downgoing muons requires below-target detectors. For aboveground objects like a volcano, the detector is placed at the volcano's base and the top portion of the volcano is imaged. For underground targets like tunnels, the detector would have to be placed below the tunnel in a deeper tunnel or adjacent borehole, which can be costly and impractical for some locations. Additionally, detecting and characterizing subsurface features like voids from tunnels can be difficult. Typical characterization methods like sonar, seismic, and ground penetrating radar have shown mixed success. Voids have a marked density contrast with surrounding materials, so using methods sensitive to density variations would be ideal. High-energy cosmic ray muons are more sensitive to density variation than other phenomena, including gravity. Their absorption rate depends on the density of the materials through which they pass. Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and detector, much like a CAT scan. Currently, tomography using downgoing muons can resolve features to the sub-meter scale. We present results of exploratory work, which demonstrates that upgoing muon fluxes appear sufficient to achieve target detection within a few months. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. Accelerating Subsurface Transport Simulation on Heterogeneous Clusters

    SciTech Connect

    Villa, Oreste; Gawande, Nitin A.; Tumeo, Antonino

    2013-09-23

    Reactive transport numerical models simulate chemical and microbiological reactions that occur along a flowpath. These models have to compute reactions for a large number of locations. They solve the set of ordinary differential equations (ODEs) that describes the reaction for each location through the Newton-Raphson technique. This technique involves computing a Jacobian matrix and a residual vector for each set of equation, and then solving iteratively the linearized system by performing Gaussian Elimination and LU decomposition until convergence. STOMP, a well known subsurface flow simulation tool, employs matrices with sizes in the order of 100x100 elements and, for numerical accuracy, LU factorization with full pivoting instead of the faster partial pivoting. Modern high performance computing systems are heterogeneous machines whose nodes integrate both CPUs and GPUs, exposing unprecedented amounts of parallelism. To exploit all their computational power, applications must use both the types of processing elements. For the case of subsurface flow simulation, this mainly requires implementing efficient batched LU-based solvers and identifying efficient solutions for enabling load balancing among the different processors of the system. In this paper we discuss two approaches that allows scaling STOMP's performance on heterogeneous clusters. We initially identify the challenges in implementing batched LU-based solvers for small matrices on GPUs, and propose an implementation that fulfills STOMP's requirements. We compare this implementation to other existing solutions. Then, we combine the batched GPU solver with an OpenMP-based CPU solver, and present an adaptive load balancer that dynamically distributes the linear systems to solve between the two components inside a node. We show how these approaches, integrated into the full application, provide speed ups from 6 to 7 times on large problems, executed on up to 16 nodes of a cluster with two AMD Opteron 6272

  3. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  4. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  5. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  6. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  7. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  8. Subsurface Mapping: A Question of Position and Interpretation

    ERIC Educational Resources Information Center

    Kellie, Andrew C.

    2009-01-01

    This paper discusses the character and challenges inherent in the graphical portrayal of features in subsurface mapping. Subsurface structures are, by their nature, hidden and must be mapped based on drilling and/or geophysical data. Efficient use of graphical techniques is central to effectively communicating the results of expensive exploration…

  9. The distribution of subsurface damage in fused silica

    SciTech Connect

    Miller, P E; Suratwala, T I; Wong, L L; Feit, M D; Menapace, J A; Davis, P J; Steele, R A

    2005-11-21

    Managing subsurface damage during the shaping process and removing subsurface damage during the polishing process is essential in the production of low damage density optical components, such as those required for use on high peak power lasers. Removal of subsurface damage, during the polishing process, requires polishing to a depth which is greater than the depth of the residual cracks present following the shaping process. To successfully manage, and ultimately remove subsurface damage, understanding the distribution and character of fractures in the subsurface region introduced during fabrication process is important. We have characterized the depth and morphology of subsurface fractures present following fixed abrasive and loose abrasive grinding processes. At shallow depths lateral cracks and an overlapping series of trailing indentation fractures were found to be present. At greater depths, subsurface damage consists of a series of trailing indentation fractures. The area density of trailing fractures changes as a function of depth, however the length and shape of individual cracks remain nearly constant for a given grinding process. We have developed and applied a model to interpret the depth and crack length distributions of subsurface surface damage in terms of key variables including abrasive size and load.

  10. DEMONSTRATION BULLETIN: SUBSURFACE VOLATILIZATION AND VENTILATION SYSTEM - BROWN & ROOT ENVIRONMENTAL

    EPA Science Inventory

    The Subsurface Volatilization and Ventilation System (SVVS*) is an in-situ vacuum extraction/air sparging and bioremediation technology for the treatment of subsurface organic contamination in soil and groundwater. The technology, developed by Billings and Associates, Inc., and o...

  11. Water and nitrogen requirements of subsurface drip irrigated pomegranate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface drip irrigation is a well-developed practice for both annual and perennial crops. The use of subsurface drip is a well-established practice in many annual row crops, e.g. tomatoes, strawberries, lettuce. However, the use of subsurface drip on perennial crops has been slow to develop. With th...

  12. 75 FR 1276 - Requirements for Subsurface Safety Valve Equipment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... Equipment AGENCY: Minerals Management Service (MMS), Interior. ACTION: Final rule. SUMMARY: The MMS is... Subsurface Safety Valve Equipment (API Spec 14A) into its regulations. The MMS is incorporating the Eleventh.../API Specification 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition,...

  13. Subsurface banding poultry litter impacts greenhouse gas emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact subsurface banding poultry litter (PL) has on greenhouse gas emissions is limited. Thus, a study was conducted in established bermudagrass pastures located in Coastal Plain and Piedmont regions to determine the effects subsurface applying PL has on soil flux using two different band spaci...

  14. Phylogenetic Characterization of Marine Benthic Archaea in Organic-Poor Sediments of the Eastern Equatorial Pacific Ocean (ODP Site 1225)

    PubMed Central

    Lauer, Antje; Sørensen, Ketil Bernt; Teske, Andreas

    2016-01-01

    Sequencing surveys of microbial communities in marine subsurface sediments have focused on organic-rich, continental margins; the database for organic-lean deep-sea sediments from mid-ocean regions is underdeveloped. The archaeal community in subsurface sediments of ODP Site 1225 in the eastern equatorial Pacific (3760 m water depth; 1.1 and 7.8 m sediment depth) was analyzed by PCR, cloning and sequencing, and by denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes. Three uncultured archaeal lineages with different depth distributions were found: Marine Group I (MG-I) within the Thaumarchaeota, its sister lineage Marine Benthic Group A (MBG-A), the phylum-level archaeal lineage Marine Benthic Group B (also known as Deep-Sea Archaeal Group or Lokiarchaeota), and the Deep-Sea Euryarchaeotal Group 3. The MG-I phylotypes included representatives of sediment clusters that are distinct from the pelagic members of this phylum. On the scale from fully oxidized, extremely organic carbon-depleted sediments (for example, those the South Pacific Gyre) to fully reduced, organic carbon-rich marine subsurface sediments (such as those of the Peru Margin), Ocean Drilling Program (ODP) Site 1225 falls into the non-extreme organic carbon-lean category, and harbors archaeal communities from both ends of the spectrum. PMID:27681926

  15. Phylogenetic Characterization of Marine Benthic Archaea in Organic-Poor Sediments of the Eastern Equatorial Pacific Ocean (ODP Site 1225).

    PubMed

    Lauer, Antje; Sørensen, Ketil Bernt; Teske, Andreas

    2016-09-06

    Sequencing surveys of microbial communities in marine subsurface sediments have focused on organic-rich, continental margins; the database for organic-lean deep-sea sediments from mid-ocean regions is underdeveloped. The archaeal community in subsurface sediments of ODP Site 1225 in the eastern equatorial Pacific (3760 m water depth; 1.1 and 7.8 m sediment depth) was analyzed by PCR, cloning and sequencing, and by denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes. Three uncultured archaeal lineages with different depth distributions were found: Marine Group I (MG-I) within the Thaumarchaeota, its sister lineage Marine Benthic Group A (MBG-A), the phylum-level archaeal lineage Marine Benthic Group B (also known as Deep-Sea Archaeal Group or Lokiarchaeota), and the Deep-Sea Euryarchaeotal Group 3. The MG-I phylotypes included representatives of sediment clusters that are distinct from the pelagic members of this phylum. On the scale from fully oxidized, extremely organic carbon-depleted sediments (for example, those the South Pacific Gyre) to fully reduced, organic carbon-rich marine subsurface sediments (such as those of the Peru Margin), Ocean Drilling Program (ODP) Site 1225 falls into the non-extreme organic carbon-lean category, and harbors archaeal communities from both ends of the spectrum.

  16. 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

  17. Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere

    PubMed Central

    Ventura, Gregory T.; Kenig, Fabien; Reddy, Christopher M.; Schieber, Juergen; Frysinger, Glenn S.; Nelson, Robert K.; Dinel, Etienne; Gaines, Richard B.; Schaeffer, Philippe

    2007-01-01

    Highly cracked and isomerized archaeal lipids and bacterial lipids, structurally changed by thermal stress, are present in solvent extracts of 2,707- to 2,685-million-year-old (Ma) metasedimentary rocks from Timmins, ON, Canada. These lipids appear in conventional gas chromatograms as unresolved complex mixtures and include cyclic and acyclic biphytanes, C36–C39 derivatives of the biphytanes, and C31–C35 extended hopanes. Biphytane and extended hopanes are also found in high-pressure catalytic hydrogenation products released from solvent-extracted sediments, indicating that archaea and bacteria were present in Late Archean sedimentary environments. Postdepositional, hydrothermal gold mineralization and graphite precipitation occurred before metamorphism (≈2,665 Ma). Late Archean metamorphism significantly reduced the kerogen's adsorptive capacity and severely restricted sediment porosity, limiting the potential for post-Archean additions of organic matter to the samples. Argillites exposed to hydrothermal gold mineralization have disproportionately high concentrations of extractable archaeal and bacterial lipids relative to what is releasable from their respective high-pressure catalytic hydrogenation product and what is observed for argillites deposited away from these hydrothermal settings. The addition of these lipids to the sediments likely results from a Late Archean subsurface hydrothermal biosphere of archaea and bacteria. PMID:17726114

  18. Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Fredrickson, Jim K.; Bjornstad, Bruce N.; Konopka, Allan

    2011-11-29

    Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington State (USA) was investigated by analyzing samples recovered from depths of 9 to 52 m. Approximately 8000 near full-length 16S rRNA gene sequences were analyzed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (Operational Taxonomic Units at the 97% identity level), respectively. Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (Chao1 estimator) was highest (>700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic interface, richness was about 325 and declined to less than 50 in the deeper reduced zones. The deeper Ringold strata were characterized by a preponderance (ca. 90%) of Proteobacteria. The Bacterial community in the oxic sediments contained not only members of 9 well-recognized phyla but also an unusually high proportion of 3 candidate divisions (GAL15, NC10, and SPAM). Additionally, novel phylogenetic orders were identified within the Delta-proteobacteria, a clade rich in microbes that carry out redox transformations of metals that are important contaminants on the Hanford Site.

  19. Molecular evidence of Late Archean archaea and the presence of a subsurface hydrothermal biosphere.

    PubMed

    Ventura, Gregory T; Kenig, Fabien; Reddy, Christopher M; Schieber, Juergen; Frysinger, Glenn S; Nelson, Robert K; Dinel, Etienne; Gaines, Richard B; Schaeffer, Philippe

    2007-09-04

    Highly cracked and isomerized archaeal lipids and bacterial lipids, structurally changed by thermal stress, are present in solvent extracts of 2,707- to 2,685-million-year-old (Ma) metasedimentary rocks from Timmins, ON, Canada. These lipids appear in conventional gas chromatograms as unresolved complex mixtures and include cyclic and acyclic biphytanes, C36-C39 derivatives of the biphytanes, and C31-C35 extended hopanes. Biphytane and extended hopanes are also found in high-pressure catalytic hydrogenation products released from solvent-extracted sediments, indicating that archaea and bacteria were present in Late Archean sedimentary environments. Postdepositional, hydrothermal gold mineralization and graphite precipitation occurred before metamorphism (approximately 2,665 Ma). Late Archean metamorphism significantly reduced the kerogen's adsorptive capacity and severely restricted sediment porosity, limiting the potential for post-Archean additions of organic matter to the samples. Argillites exposed to hydrothermal gold mineralization have disproportionately high concentrations of extractable archaeal and bacterial lipids relative to what is releasable from their respective high-pressure catalytic hydrogenation product and what is observed for argillites deposited away from these hydrothermal settings. The addition of these lipids to the sediments likely results from a Late Archean subsurface hydrothermal biosphere of archaea and bacteria.

  20. SHUTTLE IMAGING RADAR: PHYSICAL CONTROLS ON SIGNAL PENETRATION AND SUBSURFACE SCATTERING IN THE EASTERN SAHARA.

    USGS Publications Warehouse

    Schaber, Gerald G.; McCauley, John F.; Breed, Carol S.; Olhoeft, Gary R.

    1986-01-01

    It is found that the Shuttle Imaging Radar A (SIR-A) signal penetration and subsurface backscatter within the upper meter or so of the sediment blanket in the Eastern Sahara of southern Egypt and northern Sudan are enhanced both by radar sensor parameters and by the physical and chemical characteristics of eolian and alluvial materials. The near-surface stratigraphy, the electrical properties of materials, and the types of radar interfaces found to be responsible for different classes of SIR-A tonal response are summarized. The dominant factors related to efficient microwave signal penetration into the sediment blanket include 1) favorable distribution of particle sizes, 2) extremely low moisture content and 3) reduced geometric scattering at the SIR-A frequency (1. 3 GHz). The depth of signal penetration that results in a recorded backscatter, called radar imaging depth, was documented in the field to be a maximum of 1. 5 m, or 0. 25 times the calculated skin depth, for the sediment blanket. The radar imaging depth is estimated to be between 2 and 3 m for active sand dune materials.

  1. Clogging influence on metals migration and removal in sub-surface flow constructed wetlands.

    PubMed

    Ranieri, Ezio; Young, Thomas M

    2012-03-15

    Chromium (Cr) and Nickel (Ni) removal from secondary effluent has been evaluated in a four year research program to determine the effectiveness of Sub-Surface Flow (SSF) Constructed Wetlands (cw(s)). Tests were performed in small scale (10 l/h) and full scale (150 m(3)/d) SSF cw(s). Metals removal was also assessed as a function of increased clogging that occurred in the cw(s) over the course of the study. Cr and Ni content were evaluated in sediments at various locations along the flow path and in plant tissues by sampling Phragmites australis roots, stems and leaves.