Source differentiation of BTEX compounds in groundwater contaminated due to refinery activities.

This study aims to identify sources of groundwater contamination in a refinery area using integrated compound-specific stable isotope analysis (CSIA), oil fingerprinting techniques, hydrogeological data, and distillation analysis. The investigations focused on determination of the origin of benzene, toluene, ethylbenzene, and xylenes (BTEX), and aliphatic hydrocarbons as well. Groundwater and floating oil samples were collected from extraction wells for analysis.

Anaerobic dihydrogen consumption of nutrient-limited aquifer sediment microbial communities examined by stable isotope analysis.

The biogeochemical consequences of dihydrogen (H) underground storage in porous aquifers are poorly understood. Here, the effects of nutrient limitations on anaerobic H oxidation of an aquifer microbial community in sediment microcosms were determined in order to evaluate possible responses to high H partial pressures. Hydrogen isotope analyses of H yielded isotope depletion in all biotic setups indicating microbial H consumption.

Electrogenic sulfur oxidation mediated by cable bacteria and its ecological effects.

At the sediment-water interfaces, filamentous cable bacteria transport electrons from sulfide oxidation along their filaments towards oxygen or nitrate as electron acceptors. These multicellular bacteria belonging to the family Desulfobulbaceae thus form a biogeobattery that mediates redox processes between multiple elements. Cable bacteria were first reported in 2012.

Carbon and hydrogen stable isotope fractionation due to monooxygenation of short-chain alkanes by butane monooxygenase of Bu-B1211.

Multi element compound-specific stable isotope analysis (ME-CSIA) is a tool to assess (bio)chemical reactions of molecules in the environment based on their isotopic fingerprints. To that effect, ME-CSIA concepts are initially developed with laboratory model experiments to determine the isotope fractionation factors specific for distinct (bio)chemical reactions. Here, we determined for the first time the carbon and hydrogen isotope fractionation factors for the monooxygenation of the short-chain alkanes ethane, propane, and butane.

Microbial electricity-driven anaerobic phenol degradation in bioelectrochemical systems.

Microbial electrochemical technologies have been extensively employed for phenol removal. Yet, previous research has yielded inconsistent results, leaving uncertainties regarding the feasibility of phenol degradation under strictly anaerobic conditions using anodes as sole terminal electron acceptors. In this study, we employed high-performance liquid chromatography and gas chromatography-mass spectrometry to investigate the anaerobic phenol degradation pathway.

Improving the performance of bioelectrochemical sulfate removal by applying flow mode.

Treatment of wastewater contaminated with high sulfate concentrations is an environmental imperative lacking a sustainable and environmental friendly technological solution. Microbial electrochemical technology (MET) represents a promising approach for sulfate reduction. In MET, a cathode is introduced as inexhaustible electron source for promoting sulfate reduction via direct or mediated electron transfer.

Effect of temperature on microbial reductive dehalogenation of chlorinated ethenes: a review.

Temperature is a key factor affecting microbial activity and ecology. An increase in temperature generally increases rates of microbial processes up to a certain threshold, above which rates decline rapidly. In the subsurface, temperature of groundwater is usually stable and related to the annual average temperature at the surface.

Structure and functional capacity of a benzene-mineralizing, nitrate-reducing microbial community.

Aims: How benzene is metabolized by microbes under anoxic conditions is not fully understood. Here, we studied the degradation pathways in a benzene-mineralizing, nitrate-reducing enrichment culture.

Methods And Results: Benzene mineralization was dependent on the presence of nitrate and correlated to the enrichment of a Peptococcaceae phylotype only distantly related to known anaerobic benzene degraders of this family.

Sulfidic acetate mineralization at 45°C by an aquifer microbial community: key players and effects of heat changes on activity and community structure.

High-Temperature Aquifer Thermal Energy Storage (HT-ATES) is a sustainable approach for integrating thermal energy from various sources into complex energy systems. Temperatures ≥45°C, which are relevant in impact zones of HT-ATES systems, may dramatically influence the structure and activities of indigenous aquifer microbial communities. Here, we characterized an acetate-mineralizing, sulfate-reducing microbial community derived from an aquifer and adapted to 45°C.

OrtSuite: from genomes to prediction of microbial interactions within targeted ecosystem processes.

The high complexity found in microbial communities makes the identification of microbial interactions challenging. To address this challenge, we present OrtSuite, a flexible workflow to predict putative microbial interactions based on genomic content of microbial communities and targeted to specific ecosystem processes. The pipeline is composed of three user-friendly bash commands.

Iron corrosion by methanogenic archaea characterized by stable isotope effects and crust mineralogy.

Carbon and hydrogen stable isotope effects associated with methane formation by the corrosive archaeon Methanobacterium strain IM1 were determined during growth with hydrogen and iron. Isotope analyses were complemented by structural, elemental and molecular composition analyses of corrosion crusts. During growth with H , strain IM1 formed methane with average δ C of -43.

Complex Odontoma in a Young Captive Reticulated Giraffe (Giraffa camelopardalis reticulata).

Complex odontoma is a rare odontogenic lesion reported in rodents (order: Rodentia) and odd-toed ungulates (order: Perissodactyla), to name a few, and only in bovine animals of the order Artiodactyla. A 3-year-old female giraffe presented with a steadily proliferating, firm mass in the rostral mandible. With further expansion and ulceration of the mass, the general condition of the giraffe deteriorated and it was euthanized.

Monitoring of the effects of a temporally limited heat stress on microbial communities in a shallow aquifer.

Aquifer thermal energy storage (ATES) is a key concept for the use of renewable energy resources. Interest in ATES performed at high temperature (HT-ATES; > 60 °C) is increasing due to higher energetic efficiencies. HT-ATES induces temperature fluctuations that exceed the natural variability in shallow aquifers, which could lead to adverse effects in subsurface ecosystems by altering the groundwater chemistry, biodiversity, and microbial metabolic activity, resulting in changes of the groundwater quality, biogeochemical processes, and ecosystem functions.

Benzene degradation in contaminated aquifers: Enhancing natural attenuation by injecting nitrate.

Natural attenuation processes depend on the availability of suitable electron acceptors. At the megasite Zeitz, concentrations of the main contaminant benzene were observed to increase constantly in the lower aquifer to levels of more than 2.5 mM.

Clinical Conundrums When Integrating the QbTest into a Standard ADHD Assessment of Children and Young People.

The uptake of the QbTest in clinical practice is increasing and has recently been supported by research evidence proposing its effectiveness in relation to clinical decision-making. However, the exact underlying process leading to this clinical benefit is currently not well established and requires further clarification. For the clinician, certain challenges arise when adding the QbTest as a novel method to standard clinical practice, such as having the skills required to interpret neuropsychological test information and assess for diagnostically relevant neurocognitive domains that are related to attention-deficit hyperactivity disorder (ADHD), or how neurocognitive domains express themselves within the behavioral classifications of ADHD and how the quantitative measurement of activity in a laboratory setting compares with real-life (ecological validity) situations as well as the impact of comorbidity on test results.

Effect of Temperature on Acetate Mineralization Kinetics and Microbial Community Composition in a Hydrocarbon-Affected Microbial Community During a Shift From Oxic to Sulfidogenic Conditions.

Aquifer thermal energy storage (ATES) allows for the seasonal storage and extraction of heat in the subsurface thus reducing reliance on fossil fuels and supporting decarbonization of the heating and cooling sector. However, the impacts of higher temperatures toward biodiversity and ecosystem services in the subsurface environment remain unclear. Here, we conducted a laboratory microcosm study comprising a hydrocarbon-degrading microbial community from a sulfidic hydrocarbon-contaminated aquifer spiked with C-labeled acetate and incubated at temperatures between 12 and 80°C to evaluate (i) the extent and rates of acetate mineralization and (ii) the resultant temperature-induced shifts in the microbial community structure.

Temperature management potentially affects carbon mineralization capacity and microbial community composition of a shallow aquifer.

High-temperature aquifer thermal energy storage (HT-ATES) is a promising technique to reduce the CO2 footprint of heat supply in the frame of transitioning to renewable energies. However, HT-ATES causes temperature fluctuations in groundwater ecosystems potentially affecting important microbial-mediated ecosystem services. Hence, assessing the impact of increasing temperatures on the structure and functioning of aquifer microbiomes is crucial to evaluate potential environmental risks associated with HT-ATES.

Anaerobic benzene mineralization by natural microbial communities from Niger Delta.

The Niger Delta is one of the most damaged ecosystems in the world, mainly due to petroleum contamination by oil exploration accidents. We investigated the natural attenuation potential of Niger Delta subsurface sediment samples for anaerobic hydrocarbon degradation using benzene as a model compound under iron-reducing, sulfate-reducing, and methanogenic conditions. Benzene was slowly mineralized under methanogenic and iron-reducing conditions using nitrilotriacetic acid (NTA)-Fe(III), or poorly crystalline Fe(III) oxyhydroxides as electron acceptors, analyzed by measurement of CO produced from added C-labelled benzene.

Dynamics of hydrocarbon mineralization characterized by isotopic analysis at a jet-fuel-contaminated site in subtropical climate.

Release of benzene, toluene, ethylbenzene, and xylene (BTEX) as components of the light non-aqueous phase liquids (LNAPL) contaminates soil and groundwater. Assessing the mechanisms of degradation and mineralization of BTEX in groundwater helps understand the migration of the dissolved plume, enabling the reduction of risks to humans. Here, we studied the fate of ethylbezene, m,p-xylenes and o-xylenes and the accompanying formation of methane in a Cenozoic lateritic aquifer in Brazil by compound-specific carbon stable isotope analysis (CSIA), to gain insights into the complex dynamics of release and biodegradation of BTEX in the LNAPL source zone.

H Kinetic Isotope Fractionation Superimposed by Equilibrium Isotope Fractionation During Hydrogenase Activity of Strain Miyazaki.

We determined H stable isotope fractionation at natural abundances associated with hydrogenase activity by whole cells of strain Miyazaki F expressing a NiFe(Se) hydrogenase. Inhibition of sulfate reduction by molybdate inhibited the overall oxidation of hydrogen but still facilitated an equilibrium isotope exchange reaction with water. The theoretical equilibrium isotope exchange δH-values of the chemical exchange reaction were identical to the hydrogenase reaction, as confirmed using three isotopically different waters with δH-values of - 62, +461, and + 1533‰.

Anaerobic methane oxidation coupled to sulfate reduction in a biotrickling filter: Reactor performance and microbial community analysis.

The aim of this work was to evaluate the performance of a biotrickling filter (BTF) packed with polyurethane foam and pall rings for the enrichment of microorganisms mediating anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) by activity tests and microbial community analysis. A BTF was inoculated with microorganisms from a known AOM active deep sea sediment collected at a depth of 528 m below the sea level (Alpha Mound, Gulf of Cadiz). The microbial community analysis was performed by catalyzed reporter deposition - fluorescence in situ hybridization (CARD-FISH) and 16S rRNA sequence analysis.

Carbon and hydrogen isotopic fractionation during abiotic hydrolysis and aerobic biodegradation of phthalate esters.

We systematically investigated the changes of carbon and hydrogen isotope signatures of three phthalate esters (PAEs) during (i) abiotic hydrolysis over the pH range of 2, 7 and 10, and (ii) aerobic biodegradation initiated by hydrolysis by Rhodococcus opacus strain DSM 43250. Significant carbon isotopic fractionation was exhibited under all investigated conditions. Hydrogen isotopic fractionation was observed in some experiments and is hypothesized to be a secondary isotope effect due to the absence of a hydrogen bond cleavage during hydrolysis.

Anaerobic biotransformation of hexachlorocyclohexane isomers by Dehalococcoides species and an enrichment culture.

The biotransformation of hexachlorocyclohexane isomers (HCH) by two Dehalococcoides mccartyi strains (195 and BTF08) and an enrichment culture was investigated and compared to conversion by the obligate anaerobic strain Clostridium pasteurianum strain DSMZ 525. The D. mccartyi strains preferentially transformed γ-HCH over α-HCH and δ-HCH isomers while β-HCH biotransformation was not significant.