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Schmidt SI, Cuthbert MO, Schwientek M. Towards an integrated understanding of how micro scale processes shape groundwater ecosystem functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 592:215-227. [PMID: 28319709 DOI: 10.1016/j.scitotenv.2017.03.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Micro scale processes are expected to have a fundamental role in shaping groundwater ecosystems and yet they remain poorly understood and under-researched. In part, this is due to the fact that sampling is rarely carried out at the scale at which microorganisms, and their grazers and predators, function and thus we lack essential information. While set within a larger scale framework in terms of geochemical features, supply with energy and nutrients, and exchange intensity and dynamics, the micro scale adds variability, by providing heterogeneous zones at the micro scale which enable a wider range of redox reactions. Here we outline how understanding micro scale processes better may lead to improved appreciation of the range of ecosystems functions taking place at all scales. Such processes are relied upon in bioremediation and we demonstrate that ecosystem modelling as well as engineering measures have to take into account, and use, understanding at the micro scale. We discuss the importance of integrating faunal processes and computational appraisals in research, in order to continue to secure sustainable water resources from groundwater.
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Affiliation(s)
- Susanne I Schmidt
- Centre for Systems Biology, University of Birmingham, Birmingham, UK.
| | - Mark O Cuthbert
- Connected Waters Initiative Research Centre, UNSW Australia, 110 King Street, Manly Vale 2093, Australia; Department of Geography, University College London, Gower Street, London, WC1E 6BT, UK
| | - Marc Schwientek
- Center of Applied Geoscience, University of Tübingen, 72074 Tübingen, Germany
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52
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Campeão ME, Reis L, Leomil L, de Oliveira L, Otsuki K, Gardinali P, Pelz O, Valle R, Thompson FL, Thompson CC. The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation. Front Microbiol 2017; 8:1019. [PMID: 28659874 PMCID: PMC5468453 DOI: 10.3389/fmicb.2017.01019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 05/22/2017] [Indexed: 12/05/2022] Open
Abstract
One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical–chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae, and Alcanivoracaceae), archaea (e.g., Halobacteriaceae, Desulfurococcaceae, and Methanobacteriaceae), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web.
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Affiliation(s)
- Mariana E Campeão
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Luciana Reis
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Luciana Leomil
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Louisi de Oliveira
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Koko Otsuki
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Piero Gardinali
- Department of Chemistry, Florida International University, MiamiFL, United States
| | - Oliver Pelz
- BP Exploration & Production Inc., HoustonTX, United States
| | - Rogerio Valle
- SAGE/COPPE, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Fabiano L Thompson
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil.,SAGE/COPPE, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Cristiane C Thompson
- Institute of Biology, Federal University of Rio de JaneiroRio de Janeiro, Brazil
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53
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Oko BJ, Tao Y, Stuckey DC. Dynamics of two methanogenic microbiomes incubated in polycyclic aromatic hydrocarbons, naphthenic acids, and oil field produced water. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:123. [PMID: 28503198 PMCID: PMC5426053 DOI: 10.1186/s13068-017-0812-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/04/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Oil field produced water (OFPW) is widely produced in large volumes around the world. Transforming the organic matter in OFPW into bioenergy, such as biomethane, is one promising way to sustainability. However, OFPW is difficult to biologically degrade because it contains complex compounds such as naphthenic acids (NAs), or polycyclic aromatic hydrocarbons (PAHs). Although active microbial communities have been found in many oil reservoirs, little is known about how an exotic microbiome, e.g. the one which originates from municipal wastewater treatment plants, would evolve when incubated with OFPW. RESULTS In this study, we harvested methanogenic biomass from two sources: a full-scale anaerobic digester (AD) treating oil and gas processing wastewater (named O&G sludge), and from a full-scale AD reactor treating multiple fractions of municipal solid wastes (named MS, short for mixed sludge). Both were incubated in replicate microcosms fed with PAHs, NAs, or OFPW. The results showed that the PAHs, NAs, and OFPW feeds could rapidly alter the methanogenic microbiomes, even after 14 days, while the O&G sludge adapted faster than the mixed sludge in all the incubations. Two rarely reported microorganisms, a hydrogenotrophic methanogen Candidatus methanoregula and a saccharolytic fermenter Kosmotoga, were found to be prevalent in the PAHs and OFPW microcosms, and are likely to play an important role in the syntrophic degradation of PAHs and OFPW, cooperating with methanogens such as Methanoregula, Methanosarcina, or Methanobacterium. CONCLUSIONS The dominant phyla varied in certain patterns during the incubations, depending on the biomass source, feed type, and variation in nutrients. The sludge that originated from the oil and gas processing wastewater treatment (O&G) reactor adapted faster than the one from municipal solid waste reactors, almost certainly because the O&G biomass had been "pre-selected" by the environment. This study reveals the importance of biomass selection for other crude oil-waste-related bioengineering studies, such as bioaugmentation and bioremediation.
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Affiliation(s)
- Bonahis J. Oko
- Department of Chemical Engineering, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ UK
| | - Yu Tao
- Department of Chemical Engineering, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ UK
| | - David C. Stuckey
- Department of Chemical Engineering, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ UK
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54
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Lin YS, Koch BP, Feseker T, Ziervogel K, Goldhammer T, Schmidt F, Witt M, Kellermann MY, Zabel M, Teske A, Hinrichs KU. Near-surface Heating of Young Rift Sediment Causes Mass Production and Discharge of Reactive Dissolved Organic Matter. Sci Rep 2017; 7:44864. [PMID: 28327661 PMCID: PMC5361187 DOI: 10.1038/srep44864] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 02/15/2017] [Indexed: 11/09/2022] Open
Abstract
Ocean margin sediments have been considered as important sources of dissolved organic carbon (DOC) to the deep ocean, yet the contribution from advective settings has just started to be acknowledged. Here we present evidence showing that near-surface heating of sediment in the Guaymas Basin, a young extensional depression, causes mass production and discharge of reactive dissolved organic matter (DOM). In the sediment heated up to ~100 °C, we found unexpectedly low DOC concentrations in the pore waters, reflecting the combined effect of thermal desorption and advective fluid flow. Heating experiments suggested DOC production to be a rapid, abiotic process with the DOC concentration increasing exponentially with temperature. The high proportions of total hydrolyzable amino acids and presence of chemical species affiliated with activated hydrocarbons, carbohydrates and peptides indicate high reactivity of the DOM. Model simulation suggests that at the local scale, near-surface heating of sediment creates short and massive DOC discharge events that elevate the bottom-water DOC concentration. Because of the heterogeneous distribution of high heat flow areas, the expulsion of reactive DOM is spotty at any given time. We conclude that hydrothermal heating of young rift sediments alter deep-ocean budgets of bioavailable DOM, creating organic-rich habitats for benthic life.
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Affiliation(s)
- Yu-Shih Lin
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany.,Department of Oceanography, National Sun Yat-Sen University, 80424 Kaohsiung, Taiwan
| | - Boris P Koch
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany.,Alfred-Wegener-Institut Helmholtz Zentrum für Polar und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany
| | - Tomas Feseker
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
| | - Kai Ziervogel
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, 27599 NC, USA
| | - Tobias Goldhammer
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany.,Leibniz Institute of Freshwater Ecology and Inland Fisheries, 12587 Berlin, Germany
| | - Frauke Schmidt
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
| | | | - Matthias Y Kellermann
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
| | - Matthias Zabel
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
| | - Andreas Teske
- Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, 27599 NC, USA
| | - Kai-Uwe Hinrichs
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Bremen, Germany
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55
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Li Y, Harir M, Lucio M, Gonsior M, Koch BP, Schmitt-Kopplin P, Hertkorn N. Comprehensive structure-selective characterization of dissolved organic matter by reducing molecular complexity and increasing analytical dimensions. WATER RESEARCH 2016; 106:477-487. [PMID: 27770724 DOI: 10.1016/j.watres.2016.10.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 05/26/2023]
Abstract
Deciphering the molecular codes of dissolved organic matter (DOM) improves our understanding of its role in the global element cycles and its active involvement in ecosystem services. This study demonstrates comprehensive characterization of DOM by an initial polarity-based stepwise solid phase extraction (SPE) with single methanol elution of the cartridges, but separate collection of equal aliquots of eluate. The reduction of molecular complexity in the individual DOM fractions attenuates intermolecular interactions and substantially increases the disposable resolution of any structure selective characterization. Suwannee River DOM (SR DOM) was used to collect five distinct SPE fractions with overall 91% DOC recovery. Optical spectroscopy (UV and fluorescence spectroscopy), high-field Fourier transform ion cyclotron mass spectrometry (FTICR MS) and nuclear magnetic resonance (NMR) spectroscopy showed analogous hierarchical clustering among the five eluates corroborating the robustness of this approach. Two abundant moderately hydrophobic fractions contained most of the SR DOM compounds, with substantial proportions of aliphatics, carboxylic-rich alicyclic molecules, carbohydrates and aromatics. A minor early eluting hydrophilic fraction was highly aliphatic and presented a large diversity of alicyclic carboxylic acids, whereas the two late eluting, minor hydrophobic fractions appeared as a largely defunctionalized mixture of aliphatic molecules. Comparative mass analysis showed that fractionation of SR DOM was governed by multiple molecular interactions depending on O/C ratio, molecular weight and aromaticity. The traditional optical indices SUVA254 and fluorescence index (FI) indicated the relative aromaticity in agreement with FTICR mass and NMR spectra; the classical fluorescent peaks A and C were observed in all four latter eluates. This versatile approach can be easily expanded to preparative scale under field conditions, and transferred to different DOM sources and SPE conditions.
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Affiliation(s)
- Yan Li
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
| | - Mourad Harir
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany; Chair of Analytical Food Chemistry, Technische Universität München, 85354, Freising, Germany
| | - Marianna Lucio
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
| | - Michael Gonsior
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Salomons, MD, 20688, USA
| | - Boris P Koch
- Alfred Wegener Institute for Polar und Marine Research, Ecological Chemistry, Am Handelshafen 12, 27570, Bremerhaven, Germany; Hochschule Bremerhaven, University of Applied Sciences, An der Karlstadt 8, 27568, Bremerhaven, Germany
| | - Philippe Schmitt-Kopplin
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany; Chair of Analytical Food Chemistry, Technische Universität München, 85354, Freising, Germany
| | - Norbert Hertkorn
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany.
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56
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Yu H, Peng S, Lei L, Zhang J, Greaves TL, Zhang X. Large Scale Flow-Mediated Formation and Potential Applications of Surface Nanodroplets. ACS APPLIED MATERIALS & INTERFACES 2016; 8:22679-87. [PMID: 27500306 DOI: 10.1021/acsami.6b07200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Microscopic droplets located on a solid substrate in contact with an immiscible liquid promise a broad range of applications in miniaturized analytical techniques, fabrication of antireflective coatings, high-resolution near-field imaging techniques, and many others. A simple method of producing oil nanodroplets with desirable morphology is a bottom-up approach called solvent exchange, where nanodroplets nucleate and grow, as a good solvent of oil is displaced by a poor solvent. In this work, we have achieved the production of surface nanodroplets over a large surface area on planar or curved surfaces, guided by the principles of the solvent exchange. The droplet size is uniform over the entire surface of a planar or curved substrate and tunable. The production rate is extremely high at 10(6) nanodroplets per second. This advance in the nanodroplet production provides a general platform for droplet-based applications. Here we demonstrate that the application of surface nanodroplets in microextraction of hydrophobic solute (dye) from its highly diluted aqueous solution and in situ detection of the dye in a simple process, and in fabrication of highly ordered array of microlens arrays and polymer-capped microstructures by simple processes.
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Affiliation(s)
- Haitao Yu
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia
- Physics of Fluids Group, Department of Science and Engineering, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Shuhua Peng
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia
| | - Lei Lei
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia
- School of Electric Power Engineering, China University of Mining and Technology , Xuzhou, Jiangsu 221000, China
| | - Jiwei Zhang
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia
| | - Tamar L Greaves
- School of Sciences, RMIT University , Melbourne, VIC 3001, Australia
| | - Xuehua Zhang
- Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia
- Physics of Fluids Group, Department of Science and Engineering, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
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57
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Zhang Y, Zhu B, Liu Y, Wittstock G. Hydrodynamic dispensing and electrical manipulation of attolitre droplets. Nat Commun 2016; 7:12424. [PMID: 27514279 PMCID: PMC4990644 DOI: 10.1038/ncomms12424] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/29/2016] [Indexed: 11/08/2022] Open
Abstract
Dispensing and manipulation of small droplets is important in bioassays, chemical analysis and patterning of functional inks. So far, dispensing of small droplets has been achieved by squeezing the liquid out of a small orifice similar in size to the droplets. Here we report that instead of squeezing the liquid out, small droplets can also be dispensed advantageously from large orifices by draining the liquid out of a drop suspended from a nozzle. The droplet volume is adjustable from attolitre to microlitre. More importantly, the method can handle suspensions and liquids with viscosities as high as thousands mPa s markedly increasing the range of applicable liquids for controlled dispensing. Furthermore, the movement of the dispensed droplets is controllable by the direction and the strength of an electric field potentially allowing the use of the droplet for extracting analytes from small sample volume or placing a droplet onto a pre-patterned surface.
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Affiliation(s)
- Yanzhen Zhang
- Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
| | - Benliang Zhu
- Guangdong Province Key Laboratory of Precision Equipment and Manufacturing, School of Mechanical and Automation Engineering, South China University of Technology, 510640 Guangzhou, China
| | - Yonghong Liu
- Department of Mechanical and Electronic Engineering, College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China
| | - Gunther Wittstock
- Institute of Chemistry, Center of Interface Sciences, Faculty of Mathematics and Science, Carl von Ossietzky University of Oldenburg, D-26111 Oldenburg, Germany
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58
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Wang J, Sandoval K, Ding Y, Stoeckel D, Minard-Smith A, Andersen G, Dubinsky EA, Atlas R, Gardinali P. Biodegradation of dispersed Macondo crude oil by indigenous Gulf of Mexico microbial communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 557-558:453-468. [PMID: 27017076 DOI: 10.1016/j.scitotenv.2016.03.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 06/05/2023]
Abstract
Because of the extreme conditions of the Deepwater Horizon (DWH) release (turbulent flow at 1500m depth and 5°C water temperature) and the sub-surface application of dispersant, small but neutrally buoyant oil droplets <70μm were formed, remained in the water column and were subjected to in-situ biodegradation processes. In order to investigate the biodegradation of Macondo oil components during the release, we designed and performed an experiment to evaluate the interactions of the indigenous microbial communities present in the deep waters of the Gulf of Mexico (GOM) with oil droplets of two representative sizes (10μm and 30μm median volume diameter) created with Macondo source oil in the presence of Corexit 9500 using natural seawater collected at the depth of 1100-1300m in the vicinity of the DWH wellhead. The evolution of the oil was followed in the dark and at 5°C for 64days by collecting sacrificial water samples at fixed intervals and analyzing them for a wide range of chemical and biological parameters including volatile components, saturated and aromatic hydrocarbons, dispersant markers, dissolved oxygen, nutrients, microbial cell counts and microbial population dynamics. A one phase exponential decay from a plateau model was used to calculate degradation rates and lag times for more than 150 individual oil components. Calculations were normalized to a conserved petroleum biomarker (30αβ-hopane). Half-lives ranged from about 3days for easily degradable compounds to about 60days for higher molecular weight aromatics. Rapid degradation was observed for BTEX, 2-3 ring PAHs, and n-alkanes below n-C23. The results in this experimental study showed good agreement with the n-alkane (n-C13 to n-C26) half-lives (0.6-9.5days) previously reported for the Deepwater Horizon plume samples and other laboratory studies with chemically dispersed Macondo oil conducted at low temperatures (<8°C). The responses of the microbial populations also were consistent with what was reported during the actual oil release, e.g. Colwellia, Cycloclasticus and Oceanospirillales (including the specific DWH Oceanospirillales) were present and increased in numbers indicating that they were degrading components of the oil. The consistency of the field and laboratory data indicate that these results could be used, in combination with other field and model data to characterize the dissipation of Macondo oil in the deepwater environment as part of the risk assessment estimations.
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Affiliation(s)
- Jian Wang
- Southeaest Environmental Research Center, Florida International University, North Miami Beach, FL 33181, United States
| | - Kathia Sandoval
- Southeaest Environmental Research Center, Florida International University, North Miami Beach, FL 33181, United States
| | - Yan Ding
- Southeaest Environmental Research Center, Florida International University, North Miami Beach, FL 33181, United States
| | | | | | - Gary Andersen
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Eric A Dubinsky
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Ronald Atlas
- Department of Biology, University of Louisville, Louisville, KY 40292, United States
| | - Piero Gardinali
- Southeaest Environmental Research Center, Florida International University, North Miami Beach, FL 33181, United States; Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States.
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59
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Evaluation of bacterial diversity recovered from petroleum samples using different physical matrices. Braz J Microbiol 2016; 47:712-23. [PMID: 27282730 PMCID: PMC4927652 DOI: 10.1016/j.bjm.2016.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 11/24/2015] [Indexed: 11/23/2022] Open
Abstract
Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material.
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60
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Dvorski SEM, Gonsior M, Hertkorn N, Uhl J, Müller H, Griebler C, Schmitt-Kopplin P. Geochemistry of Dissolved Organic Matter in a Spatially Highly Resolved Groundwater Petroleum Hydrocarbon Plume Cross-Section. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5536-46. [PMID: 27152868 DOI: 10.1021/acs.est.6b00849] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
At numerous groundwater sites worldwide, natural dissolved organic matter (DOM) is quantitatively complemented with petroleum hydrocarbons. To date, research has been focused almost exclusively on the contaminants, but detailed insights of the interaction of contaminant biodegradation, dominant redox processes, and interactions with natural DOM are missing. This study linked on-site high resolution spatial sampling of groundwater with high resolution molecular characterization of DOM and its relation to groundwater geochemistry across a petroleum hydrocarbon plume cross-section. Electrospray- and atmospheric pressure photoionization (ESI, APPI) ultrahigh resolution mass spectrometry (FT-ICR-MS) revealed a strong interaction between DOM and reactive sulfur species linked to microbial sulfate reduction, i.e., the key redox process involved in contaminant biodegradation. Excitation emission matrix (EEM) fluorescence spectroscopy in combination with Parallel Factor Analysis (PARAFAC) modeling attributed DOM samples to specific contamination traits. Nuclear magnetic resonance (NMR) spectroscopy evaluated the aromatic compounds and their degradation products in samples influenced by the petroleum contamination and its biodegradation. Our orthogonal high resolution analytical approach enabled a comprehensive molecular level understanding of the DOM with respect to in situ petroleum hydrocarbon biodegradation and microbial sulfate reduction. The role of natural DOM as potential cosubstrate and detoxification reactant may improve future bioremediation strategies.
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Affiliation(s)
- Sabine E-M Dvorski
- Helmholtz Zentrum München-German Research Center for Environmental Health , Research Unit Analytical BioGeoChemistry, D-85764 Neuherberg, Germany
| | - Michael Gonsior
- University of Maryland Center for Environmental Science , Chesapeake Biological Laboratory, Solomons, Maryland 20688, United States
| | - Norbert Hertkorn
- Helmholtz Zentrum München-German Research Center for Environmental Health , Research Unit Analytical BioGeoChemistry, D-85764 Neuherberg, Germany
| | - Jenny Uhl
- Helmholtz Zentrum München-German Research Center for Environmental Health , Research Unit Analytical BioGeoChemistry, D-85764 Neuherberg, Germany
| | - Hubert Müller
- Helmholtz Zentrum München-German Research Center for Environmental Health , Institute of Groundwater Ecology, D-85764 Neuherberg, Germany
| | - Christian Griebler
- Helmholtz Zentrum München-German Research Center for Environmental Health , Institute of Groundwater Ecology, D-85764 Neuherberg, Germany
| | - Philippe Schmitt-Kopplin
- Helmholtz Zentrum München-German Research Center for Environmental Health , Research Unit Analytical BioGeoChemistry, D-85764 Neuherberg, Germany
- Technische Universität München , Chair of Analytical Food Chemistry, D-85354 Freising-Weihenstephan, Germany
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61
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Jiménez N, Richnow HH, Vogt C, Treude T, Krüger M. Methanogenic Hydrocarbon Degradation: Evidence from Field and Laboratory Studies. J Mol Microbiol Biotechnol 2016; 26:227-42. [PMID: 26959375 DOI: 10.1159/000441679] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Microbial transformation of hydrocarbons to methane is an environmentally relevant process taking place in a wide variety of electron acceptor-depleted habitats, from oil reservoirs and coal deposits to contaminated groundwater and deep sediments. Methanogenic hydrocarbon degradation is considered to be a major process in reservoir degradation and one of the main processes responsible for the formation of heavy oil deposits and oil sands. In the absence of external electron acceptors such as oxygen, nitrate, sulfate or Fe(III), fermentation and methanogenesis become the dominant microbial metabolisms. The major end product under these conditions is methane, and the only electron acceptor necessary to sustain the intermediate steps in this process is CO2, which is itself a net product of the overall reaction. We are summarizing the state of the art and recent advances in methanogenic hydrocarbon degradation research. Both the key microbial groups involved as well as metabolic pathways are described, and we discuss the novel insights into methanogenic hydrocarbon-degrading populations studied in laboratory as well as environmental systems enabled by novel cultivation-based and molecular approaches. Their possible implications on energy resources, bioremediation of contaminated sites, deep-biosphere research, and consequences for atmospheric composition and ultimately climate change are also addressed.
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Affiliation(s)
- Núria Jiménez
- Department of Resource Geochemistry, BGR - Federal Institute for Geosciences and Natural Resources, Hannover, Germany
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Abstract
The evolution of habitable conditions on Mars is often tied to the existence of aquatic habitats and largely constrained to the first billion years of the planet. Here, we propose an alternate, lasting evolutionary trajectory that assumes the colonization of land habitats before the end of the Hesperian period (ca. 3 billion years ago) at a pace similar to life on Earth. Based on the ecological adaptations to increasing dryness observed in dryland ecosystems on Earth, we reconstruct the most likely sequence of events leading to a late extinction of land communities on Mars. We propose a trend of ecological change with increasing dryness from widespread edaphic communities to localized lithic communities and finally to communities exclusively found in hygroscopic substrates, reflecting the need for organisms to maximize access to atmospheric sources of water. If our thought process is correct, it implies the possibility of life on Mars until relatively recent times, perhaps even the present.
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Affiliation(s)
- Alfonso F Davila
- 1 Carl Sagan Center at the SETI Institute , Mountain View, California, USA
- 2 NASA Ames Research Center , Moffett Field, California, USA
| | - Dirk Schulze-Makuch
- 3 School of the Environment, Washington State University , Pullman, Washington, USA
- 4 Center of Astronomy and Astrophysics, Technical University Berlin , Berlin, Germany
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Yu H, Lu Z, Lohse D, Zhang X. Gravitational Effect on the Formation of Surface Nanodroplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12628-12634. [PMID: 26514099 DOI: 10.1021/acs.langmuir.5b03464] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nanoscale droplets at a solid-liquid interface are of high relevance for many fundamental phenomena and applied processes. The solvent exchange process is a simple approach to produce, e.g., oil nanodroplets over a large surface area on a substrate, by exchange oil-saturated ethanol by oil-saturated water, which has a lower oil solubility than ethanol. In this process, the size of the nanodroplets is closely related to the flow conditions. To achieve control of the droplet size, it is essential to fully understand the nucleation and growth of nanodroplets under different flow conditions. In this work, we investigate the gravitational effect on the droplet formation by the solvent exchange. We compared the droplet size as the substrate was placed on the upper or lower wall in a horizontal fluid channel or on the sides of a vertical channel with an upward or downward flow. We found significant difference in the droplet size for the three substrate positions in a wide channel with height h = 0.21 mm. The difference of droplet size was eliminated in a narrow channel with height h = 0.07 mm. The relevant dimensional control parameter for the occurrence of the gravitational effects is the Archimedes number Ar and these two heights correspond to Ar = 10 and Ar = 0.35, respectively. The gravitational effects lead to a nonsymmetric parabolic profile of the mixing front, with the velocity maximum being off-center and thus with different distances α(Ar)h and (1 - α(Ar))h to the lower and upper wall, respectively. The ratio of the total droplet volume on the lower and upper wall is theoretically found to be (α(Ar)/(1 - α(Ar)))(3). This study thus improves our understanding of the mechanism of the solvent exchange process, providing guidelines for tailoring the volume of surface nanodroplets.
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Affiliation(s)
- Haitao Yu
- Soft Matter & Interfaces Group, School of Civil, Environmental and Chemical Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Ziyang Lu
- Soft Matter & Interfaces Group, School of Civil, Environmental and Chemical Engineering, RMIT University , Melbourne, Victoria 3001, Australia
| | - Detlef Lohse
- Physics of Fluids group, Department of Science and Engineering, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
- Max Planck Institute for Dynamics and Self-Organization , 37077 Goettingen, Germany
| | - Xuehua Zhang
- Soft Matter & Interfaces Group, School of Civil, Environmental and Chemical Engineering, RMIT University , Melbourne, Victoria 3001, Australia
- Physics of Fluids group, Department of Science and Engineering, Mesa+ Institute, and J. M. Burgers Centre for Fluid Dynamics, University of Twente , P.O. Box 217, 7500 AE Enschede, The Netherlands
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64
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Cai M, Nie Y, Chi CQ, Tang YQ, Li Y, Wang XB, Liu ZS, Yang Y, Zhou J, Wu XL. Crude oil as a microbial seed bank with unexpected functional potentials. Sci Rep 2015; 5:16057. [PMID: 26525361 PMCID: PMC4630613 DOI: 10.1038/srep16057] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/01/2015] [Indexed: 01/17/2023] Open
Abstract
It was widely believed that oil is a harsh habitat for microbes because of its high toxicity and hydrophobicity. However, accumulating evidence has revealed the presence of live microbes in crude oil. Therefore, it’s of value to conduct an in-depth investigation on microbial communities in crude oil. To this end, microorganisms in oil and water phases were collected from four oil-well production mixtures in Qinghai Oilfield, China, and analyzed for their taxonomic and functional compositions via pyrosequencing and GeoChip, respectively. Hierarchical clustering of 16S rRNA gene sequences and functional genes clearly separated crude oil and water phases, suggestive of distinct taxonomic and functional gene compositions between crude oil and water phases. Unexpectedly, Pseudomonas dominated oil phase where diverse functional gene groups were identified, which significantly differed from those in the corresponding water phases. Meanwhile, most functional genes were significantly more abundant in oil phase, which was consistent with their important roles in facilitating survival of their host organisms in crude oil. These findings provide strong evidence that crude oil could be a “seed bank” of functional microorganisms with rich functional potentials. This offers novel insights for industrial applications of microbial-enhanced oil recovery and bioremediation of petroleum-polluted environments.
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Affiliation(s)
- Man Cai
- Peking University, College of Engineering, Beijing, 100871, China
| | - Yong Nie
- Peking University, College of Engineering, Beijing, 100871, China
| | - Chang-Qiao Chi
- Peking University, College of Engineering, Beijing, 100871, China
| | - Yue-Qin Tang
- Sichuan University, College of Architecture and Environment, Chengdu, 610065, China
| | - Yan Li
- Peking University, College of Engineering, Beijing, 100871, China
| | - Xing-Biao Wang
- Peking University, College of Engineering, Beijing, 100871, China
| | - Ze-Shen Liu
- Peking University, College of Engineering, Beijing, 100871, China
| | - Yunfeng Yang
- Tsinghua University, School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Beijing, 100084, China
| | - Jizhong Zhou
- Tsinghua University, School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Beijing, 100084, China
| | - Xiao-Lei Wu
- Peking University, College of Engineering, Beijing, 100871, China
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Castillo-Orozco E, Davanlou A, Choudhury PK, Kumar R. Droplet impact on deep liquid pools: Rayleigh jet to formation of secondary droplets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:053022. [PMID: 26651794 DOI: 10.1103/physreve.92.053022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Indexed: 06/05/2023]
Abstract
The impact of droplets on a deep pool has applications in cleaning up oil spills, spray cooling, painting, inkjet printing, and forensic analysis, relying on the changes in properties such as viscosity, interfacial tension, and density. Despite the exhaustive research on different aspects of droplet impact, it is not clear how liquid properties can affect the instabilities leading to Rayleigh jet breakup and number of daughter drops formed after its pinch-off. In this article, through systematic experiments we investigate the droplet impact phenomena by varying viscosity and surface tension of liquids as well as impact speeds. Further, using numerical simulations, we show that Rayleigh-Plateau instability is influenced by these parameters, and capillary time scale is the appropriate scale to normalize the breakup time. Based on Ohnesorge number (Oh) and impact Weber number (We), a regime map for no breakup, Rayleigh jet breakup, and crown splash is suggested. Interestingly, crown splash is observed to occur at all Ohnesorge numbers; however, at high Oh, a large portion of kinetic energy is dissipated, and thus the Rayleigh jet is suppressed regardless of high impact velocity. The normalized required time for the Rayleigh jet to reach its peak varies linearly with the critical height of the jet.
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Affiliation(s)
- Eduardo Castillo-Orozco
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
| | - Ashkan Davanlou
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
| | - Pretam K Choudhury
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
| | - Ranganathan Kumar
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
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Hertkorn N, Harir M, Schmitt-Kopplin P. Nontarget analysis of Murchison soluble organic matter by high-field NMR spectroscopy and FTICR mass spectrometry. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:754-68. [PMID: 26275226 DOI: 10.1002/mrc.4249] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/18/2015] [Accepted: 03/23/2015] [Indexed: 05/26/2023]
Abstract
High-field NMR spectra of Murchison meteorite methanolic extracts revealed primarily aliphatic extraterrestrial organic matter (EOM) with near statistical branching of commonly C(3-5) units separated by heteroatoms and aromatic units. The ratios of CCH, OCH and C(sp2)H units were 89 : 8 : 3, whereas carbon-based aliphatic chain termination was in the order methyl > -COOH > -CH(CH3)COOH. Aliphatic methine carbon was abundant, but its weak NMR signatures were primarily deduced from JRES (J-resolved) NMR spectra. Carbon NMR spectra were dominated by methylene and methyl carbon; strong apodization revealed methine carbon, of which about 20% was aromatic. Extrapolation provided 5-7% aromatic carbon present in Murchison soluble EOM. Compositional heterogeneity in Murchison methanolic extracts was visible in NMR and Fourier transform ion cyclotron (FTICR) mass spectra obtained from a few cubic millimeters of solid Murchison meteorite; increasing sample size enhanced uniformity of NMR spectra. Intrinsic chemical diversity and pH-dependent chemical shift variance contributed to the disparity of NMR spectra. FTICR mass spectra provided distinct clustering of CHO/CHOS and CHNO/CHNOS molecular series and confirmed the prevalence of aliphatic/alicyclic (73%) over single aromatic (21%) and polyaromatic (6%) molecular compositions, suggesting extensive aliphatic substitution of aromatic units as proposed by NMR. Murchison soluble EOM molecules feature a center with enhanced aromatic and heteroatom content, which provides rather diffuse and weak NMR signatures resulting from a huge overall chemical diversity. The periphery of Murchison EOM molecules comprises flexible branched aliphatic chains and aliphatic carboxylic acids. These project on narrow ranges of chemical shift, facilitating observation in one-dimensional and two-dimensional NMR spectra. The conformational entropy provided by these flexible surface moieties facilitates the solubility of EOM.
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Affiliation(s)
- N Hertkorn
- Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - M Harir
- Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Ph Schmitt-Kopplin
- Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstaedter Landstrasse 1, Neuherberg, Germany
- Chair of Analytical Food Chemistry, Technische Universität München, Alte Akademie 10, Freising-Weihenstephan, Germany
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67
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Roles of Thermophiles and Fungi in Bitumen Degradation in Mostly Cold Oil Sands Outcrops. Appl Environ Microbiol 2015. [PMID: 26209669 DOI: 10.1128/aem.02221-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Oil sands are surface exposed in river valley outcrops in northeastern Alberta, where flat slabs (tablets) of weathered, bitumen-saturated sandstone can be retrieved from outcrop cliffs or from riverbeds. Although the average yearly surface temperature of this region is low (0.7°C), we found that the temperatures of the exposed surfaces of outcrop cliffs reached 55 to 60°C on sunny summer days, with daily maxima being 27 to 31°C. Analysis of the cooccurrence of taxa derived from pyrosequencing of 16S/18S rRNA genes indicated that an aerobic microbial network of fungi and hydrocarbon-, methane-, or acetate-oxidizing heterotrophic bacteria was present in all cliff tablets. Metagenomic analyses indicated an elevated presence of fungal cytochrome P450 monooxygenases in these samples. This network was distinct from the heterotrophic community found in riverbeds, which included fewer fungi. A subset of cliff tablets had a network of anaerobic and/or thermophilic taxa, including methanogens, Firmicutes, and Thermotogae, in the center. Long-term aerobic incubation of outcrop samples at 55°C gave a thermophilic microbial community. Analysis of residual bitumen with a Fourier transform ion cyclotron resonance mass spectrometer indicated that aerobic degradation proceeded at 55°C but not at 4°C. Little anaerobic degradation was observed. These results indicate that bitumen degradation on outcrop surfaces is a largely aerobic process with a minor anaerobic contribution and is catalyzed by a consortium of bacteria and fungi. Bitumen degradation is stimulated by periodic high temperatures on outcrop cliffs, which cause significant decreases in bitumen viscosity.
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Abstract
Nanodroplets on a solid surface (i.e., surface nanodroplets) have practical implications for high-throughput chemical and biological analysis, lubrications, laboratory-on-chip devices, and near-field imaging techniques. Oil nanodroplets can be produced on a solid-liquid interface in a simple step of solvent exchange in which a good solvent of oil is displaced by a poor solvent. In this work, we experimentally and theoretically investigate the formation of nanodroplets by the solvent exchange process under well-controlled flow conditions. We find significant effects from the flow rate and the flow geometry on the droplet size. We develop a theoretical framework to account for these effects. The main idea is that the droplet nuclei are exposed to an oil oversaturation pulse during the exchange process. The analysis shows that the volume of the nanodroplets increases with the Peclet number Pe of the flow as ∝ Pe(3/4), which is in good agreement with our experimental results. In addition, at fixed flow rate and thus fixed Peclet number, larger and less homogeneously distributed droplets formed at less-narrow channels, due to convection effects originating from the density difference between the two solutions of the solvent exchange. The understanding from this work provides valuable guidelines for producing surface nanodroplets with desired sizes by controlling the flow conditions.
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Hosein R, Haque S, Beckles DM. Mud volcanoes of trinidad as astrobiological analogs for martian environments. Life (Basel) 2014; 4:566-85. [PMID: 25370529 PMCID: PMC4284458 DOI: 10.3390/life4040566] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/08/2014] [Accepted: 09/23/2014] [Indexed: 11/23/2022] Open
Abstract
Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region.
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Affiliation(s)
- Riad Hosein
- Department of Chemistry, University of the West Indies, St. Augustine, Trinidad, West Indies, Trinidad and Tobago.
| | - Shirin Haque
- Department of Physics, University of the West Indies, St. Augustine, Trinidad, West Indies, Trinidad and Tobago.
| | - Denise M Beckles
- Department of Chemistry, University of the West Indies, St. Augustine, Trinidad, West Indies, Trinidad and Tobago.
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Tiny water worlds float in oil reservoirs. Nature 2014. [DOI: 10.1038/nature.2014.15684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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71
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Ecosystems afloat in asphalt. Nature 2014. [DOI: 10.1038/512117d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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