Isotopic and Chemical Assessment of the Dynamics of Methane Sources and Microbial Cycling during Early Development of an Oil Sands Pit Lake

Water-capped tailings technology (WCTT) is a key component of the reclamation strategies in the Athabasca oil sands region (AOSR) of northeastern Alberta, Canada. The release of microbial methane from tailings emplaced within oil sands pit lakes, and its subsequent microbial oxidation, could inhibit the development of persistent oxygen concentrations within the water column, which are critical to the success of this reclamation approach. Here, we describe the results of a four-year (2015–2018) chemical and isotopic (δ13C) investigation into the dynamics of microbial methane cycling within Base Mine Lake (BML), the first full-scale pit lake commissioned in the AOSR. Overall, the water-column methane concentrations decreased over the course of the study, though this was dynamic both seasonally and annually. Phospholipid fatty acid (PLFA) distributions and δ13C demonstrated that dissolved methane, primarily input via fluid fine tailings (FFT) porewater advection, was oxidized by the water column microbial community at all sampling times. Modeling and under-ice observations indicated that the dissolution of methane from bubbles during ebullition, or when trapped beneath ice, was also an important source of dissolved methane. The addition of alum to BML in the fall of 2016 impacted the microbial cycling in BML, leading to decreased methane oxidation rates, the short-term dominance of a phototrophic community, and longer-term shifts in the microbial community metabolism. Overall, our results highlight a need to understand the dynamic nature of these microbial communities and the impact of perturbations on the associated biogeochemical cycling within oil sands pit lakes.

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Nitrogen- and sulfur-deposition-altered soil microbial community functions and enzyme activities in a boreal mixedwood forest in western Canada

Canadian Journal of Forest Research ◽

10.1139/cjfr-2013-0049 ◽

2013 ◽

Vol 43 (9) ◽

pp. 777-784 ◽

Cited By ~ 12

Author(s):

Ya-Lin Hu ◽

Kangho Jung ◽

De-Hui Zeng ◽

Scott X. Chang

Keyword(s):

Microbial Community ◽

Microbial Biomass ◽

Soil Microbial Community ◽

Oil Sands ◽

Soil Microbial Biomass ◽

Soil Microbial ◽

C And N ◽

Boreal Mixedwood Forest ◽

The Impact ◽

S Deposition

Chronic nitrogen (N) and (or) sulfur (S) deposition to boreal forests in the Athabasca oil sands region (AOSR) in Alberta, Canada, has been caused by oil sands mining and extraction/upgrading activities. It is important that we understand the response of microbial community function to chronic N and S deposition as microbial populations mediate soil carbon (C) and N cycles and affect ecosystem resilience. To evaluate the impact of N and (or) S deposition on soil microbial community functions, we conducted a simulated N and S deposition experiment in a boreal mixedwood forest with the following four treatments: control (CK), N addition (+N, 30 kg N·ha−1 as NH4NO3), S addition (+S, 30 kg S·ha−1 as NaSO4), and N plus S addition (+NS, 30 kg N·ha−1 + 30 kg S·ha−1), from 2006 to 2010. Nitrogen and (or) S deposition did not change soil organic carbon, total N, dissolved organic C and N, or soil microbial biomass C and N. Soil microbial community-level physiological profiles, however, were strongly affected by 5 years of N and (or) S addition. Soil β-glucosidase activity in the +NS treatment was greater than that in the +S treatment, and S addition decreased soil arylsulfatase; however, urease and dehydrogenase activities were not affected by the simulated N and (or) S deposition. Our data suggested that N and (or) S deposition strongly affected soil microbial community functions and enzymatic activities without changing soil microbial biomass in the studied boreal forest.

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Effects of Calcium and Aluminum on Particle Settling in an Oil Sands End Pit Lake

Mine Water and the Environment ◽

10.1007/s10230-021-00808-9 ◽

2021 ◽

Author(s):

Kai Wei ◽

Heidi L. Cossey ◽

Ania C. Ulrich

Keyword(s):

Surface Water ◽

Oil Sands ◽

Surface Mining ◽

Pit Lake ◽

Particle Settling ◽

Pit Lakes ◽

Fine Tailings ◽

High Turbidity ◽

Fluid Fine Tailings ◽

Al Treatment

AbstractSurface mining of oil sands ore in Alberta, Canada has generated fluid fine tailings (FFT) that must be reclaimed. End pit lakes (EPLs), which consist of thick deposits of FFT capped with water, have been proposed for FFT reclamation, and Base Mine Lake (BML) is the first full-scale demonstration EPL. However, FFT particle settling and resuspension contributes to high turbidity in the BML water cap, which may be detrimental to the development of an aquatic ecosystem. This study investigated the effect of Ca and Al treatments on turbidity mitigation. The initial turbidity was reduced from 20 NTU to less than 2 NTU in BML surface water treated with 54 mg/L of Ca or 1.1 mg/L of Al. At a concentration of 1.1 mg/L, Al reduced the initial turbidity to a greater extent, and in a shorter time, than 54 mg/L of Ca. Further, resuspended Al-treated FFT particles were 100–700 nm larger in diameter, and thus resettled faster than the resuspended untreated or Ca-treated FFT particles. The final turbidity values 21 days after resuspension of untreated and 1.7 mg/L Al-treated FFT particles in fresh BML surface water were 20.5 NTU and 2.5 NTU, respectively. Thus, Al treatment may be effective in mitigating turbidity in BML through both Al-induced coagulation and self-weight settling of the resuspended Al-treated FFT particles.

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Seasonal methane accumulation and release from a gas emission site in the central North Sea

Biogeosciences ◽

10.5194/bg-12-5261-2015 ◽

2015 ◽

Vol 12 (18) ◽

pp. 5261-5276 ◽

Cited By ~ 21

Author(s):

S. Mau ◽

T. Gentz ◽

J.-H. Körber ◽

M. E. Torres ◽

M. Römer ◽

...

Keyword(s):

North Sea ◽

Traditional Approach ◽

Turnover Time ◽

Minor Importance ◽

Microbial Oxidation ◽

Dissolved Methane ◽

Oxidation Rates ◽

Median Concentration ◽

Central North Sea ◽

Methane Concentrations

Abstract. We investigated dissolved methane distributions along a 6 km transect crossing active seep sites at 40 m water depth in the central North Sea. These investigations were done under conditions of thermal stratification in summer (July 2013) and homogenous water column in winter (January 2014). Dissolved methane accumulated below the seasonal thermocline in summer with a median concentration of 390 nM, whereas during winter, methane concentrations were typically much lower (median concentration of 22 nM). High-resolution methane analysis using an underwater mass-spectrometer confirmed our summer results and was used to document prevailing stratification over the tidal cycle. We contrast estimates of methane oxidation rates (from 0.1 to 4.0 nM day−1) using the traditional approach scaled to methane concentrations with microbial turnover time values and suggest that the scaling to concentration may obscure the ecosystem microbial activity when comparing systems with different methane concentrations. Our measured and averaged rate constants (k') were on the order of 0.01 day−1, equivalent to a turnover time of 100 days, even when summer stratification led to enhanced methane concentrations in the bottom water. Consistent with these observations, we could not detect known methanotrophs and pmoA genes in water samples collected during both seasons. Estimated methane fluxes indicate that horizontal transport is the dominant process dispersing the methane plume. During periods of high wind speed (winter), more methane is lost to the atmosphere than oxidized in the water. Microbial oxidation seems of minor importance throughout the year.

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Seasonal methane accumulation and release from a gas emission site in the central North Sea

Biogeosciences Discussions ◽

10.5194/bgd-11-18003-2014 ◽

2014 ◽

Vol 11 (12) ◽

pp. 18003-18044 ◽

Cited By ~ 1

Author(s):

S. Mau ◽

T. Gentz ◽

J. H. Körber ◽

M. Torres ◽

M. Römer ◽

...

Keyword(s):

Water Column ◽

Methane Oxidation ◽

North Sea ◽

Field Data ◽

Microbial Oxidation ◽

Dissolved Methane ◽

Median Concentration ◽

Peak Release ◽

Central North Sea ◽

Seep Site

Abstract. Hydroacoustic data document the occurrence of 5 flare clusters and several single flares from which bubbles rise through the entire water column from an active seep site at 40 m water depth in the central North Sea. We investigated the difference in dissolved methane distributions along a 6 km transect crossing this seep site during a period of seasonal summer stratification (July 2013) and a period of well mixed winter water column (January 2014). Dissolved methane accumulated below the seasonal thermocline in summer with a median concentration of 390 nM, whereas during winter, methane concentrations were much lower (median concentration of 22 nM) and punctually elevated due to bubble transport. High resolution methane analysis by an underwater mass-spectrometer confirmed our summer results and were used to document prevailing stratification over the tidal cycle. Although sufficient methane was available, microbial methane oxidation was limited during both seasons. Measured and averaged rate constants (k') using Michaelis Menten kinetics were on the order of 0.01 days-1, equivalent to a turnover time of 100 days. Time series measurements indicated an uptake of only 5–6% of the gas after 4 days, and no known methanotrophs and pmoA-genes were detected. Estimated methane fluxes indicate that horizontal eddy transport rapidly disperses dissolved methane, vertical transport becomes dominant during phases of high wind speeds, and relative to these processes, microbial methane oxidation appears to be comparably low. To bridge the discrete field data we developed a 1-D seasonal model using available year-long records of wind speed, surface temperature and thermocline depth. The model simulations show a peak release of methane at the beginning of fall when the water column becomes mixed. Consistent with our field data, inclusion of microbial methane oxidation does not change the model results significantly, thus microbial oxidation appears to be not sufficient to notably reduce methane during summer stratification before the peak release in fall.

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Interaction between the Microbial Community and Invading Escherichia coli O157:H7 in Soils from Vegetable Fields

Applied and Environmental Microbiology ◽

10.1128/aem.03046-13 ◽

2013 ◽

Vol 80 (1) ◽

pp. 70-76 ◽

Cited By ~ 24

Author(s):

Zhiyuan Yao ◽

Haizhen Wang ◽

Laosheng Wu ◽

Jianjun Wu ◽

Philip C. Brookes ◽

...

Keyword(s):

Escherichia Coli ◽

Microbial Community ◽

Soil Microbial Community ◽

Phospholipid Fatty Acid ◽

Soil Microbial Communities ◽

Principal Component ◽

Content Type ◽

E Coli ◽

Soil Microbial ◽

The Impact

ABSTRACTThe survival ofEscherichia coliO157:H7 in soils can contaminate vegetables, fruits, drinking water, etc. However, data on the impact ofE. coliO157:H7 on soil microbial communities are limited. In this study, we monitored the changes in the indigenous microbial community by using the phospholipid fatty acid (PLFA) method to investigate the interaction of the soil microbial community withE. coliO157:H7 in soils. Simple correlation analysis showed that the survival ofE. coliO157:H7 in the test soils was negatively correlated with the ratio of Gram-negative (G−) to Gram-positive (G+) bacterial PLFAs (G−/G+ratio). In particular, levels of 14 PLFAs were negatively correlated with the survival time ofE. coliO157:H7. The contents of actinomycetous and fungal PLFAs in the test soils declined significantly (P, <0.05) after 25 days of incubation withE. coliO157:H7. The G−/G+ratio declined slightly, while the ratio of bacterial to fungal PLFAs (B/F ratio) and the ratio of normal saturated PLFAs to monounsaturated PLFAs (S/M ratio) increased, afterE. coliO157:H7 inoculation. Principal component analysis results further indicated that invasion byE. coliO157:H7 had some effects on the soil microbial community. Our data revealed that the toxicity ofE. coliO157:H7 presents not only in its pathogenicity but also in its effect on soil microecology. Hence, close attention should be paid to the survival ofE. coliO157:H7 and its potential for contaminating soils.

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Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes

Microorganisms ◽

10.3390/microorganisms9071443 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1443

Author(s):

Heidi L. Cossey ◽

Mian Nabeel Anwar ◽

Petr V. Kuznetsov ◽

Ania C. Ulrich

Keyword(s):

Microbial Communities ◽

Oil Sands ◽

Threshold Velocity ◽

Water Turbidity ◽

Mixing Speed ◽

Fine Grained ◽

Pit Lakes ◽

Fine Tailings ◽

Fluid Fine Tailings ◽

The Impact

End pit lakes (EPLs) have been proposed as a method of reclaiming oil sands fluid fine tailings (FFT), which consist primarily of process-affected water and clay- and silt-sized particles. Base Mine Lake (BML) is the first full-scale demonstration EPL and contains thick deposits of FFT capped with water. Because of the fine-grained nature of FFT, turbidity generation and mitigation in BML are issues that may be detrimental to the development of an aquatic ecosystem in the water cap. Laboratory mixing experiments were conducted to investigate the effect of mudline biofilms made up of microbial communities indigenous to FFT on mitigating turbidity in EPLs. Four mixing speeds were tested (80, 120, 160, and 200 rpm), all of which are above the threshold velocity required to initiate erosion of FFT in BML. These mixing speeds were selected to evaluate (i) the effectiveness of biofilms in mitigating turbidity and (ii) the mixing speed required to ‘break’ the biofilms. The impact of biofilm age (10 weeks versus 20 weeks old) on turbidity mitigation was also evaluated. Diverse microbial communities in the biofilms included photoautotrophs, namely cyanobacteria and Chlorophyta (green algae), as well as a number of heterotrophs such as Gammaproteobacteria, Desulfobulbia, and Anaerolineae. Biofilms reduced surface water turbidity by up to 99%, depending on the biofilm age and mixing speed. Lifting and layering in the older biofilms resulted in weaker attachment to the FFT; as such, younger biofilms performed better than older biofilms. However, older biofilms still reduced turbidity by 69% to 95%, depending on the mixing speed. These results indicate that biostabilization is a promising mechanism for turbidity mitigation in EPLs.

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METHANE EBULLITION CAN INFLUENCE INTERNAL MASS LOADING IN OIL SANDS END PIT LAKES

10.1130/abs/2019am-334343 ◽

2019 ◽

Author(s):

Daniel Francis ◽

◽

Matthew B.J. Lindsay ◽

Lee Barbour

Keyword(s):

Oil Sands ◽

Internal Mass ◽

Mass Loading ◽

Pit Lakes ◽

Methane Ebullition

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Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths

Agronomy ◽

10.3390/agronomy11010173 ◽

2021 ◽

Vol 11 (1) ◽

pp. 173

Author(s):

Huiling Guan ◽

Jiangwen Fan ◽

Haiyan Zhang ◽

Warwick Harris

Keyword(s):

Microbial Community ◽

Microbial Communities ◽

Soil Depth ◽

Phospholipid Fatty Acid ◽

Soil Microbial Communities ◽

Deep Soil ◽

Soil System ◽

Soil Microbial ◽

Total Soil ◽

Karst Ecosystems

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.

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Computational Evaluation of Shock Wave Interaction with a Cylindrical Water Column

Applied Sciences ◽

10.3390/app11114934 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4934

Author(s):

Viola Rossano ◽

Giuliano De Stefano

Keyword(s):

Shock Wave ◽

Water Column ◽

Wave Interaction ◽

Navier Stokes ◽

Plane Shock ◽

Governing Equations ◽

Computational Evaluation ◽

Air Water Interface ◽

The Mean ◽

The Impact

Computational fluid dynamics was employed to predict the early stages of the aerodynamic breakup of a cylindrical water column, due to the impact of a traveling plane shock wave. The unsteady Reynolds-averaged Navier–Stokes approach was used to simulate the mean turbulent flow in a virtual shock tube device. The compressible flow governing equations were solved by means of a finite volume-based numerical method, where the volume of fluid technique was employed to track the air–water interface on the fixed numerical mesh. The present computational modeling approach for industrial gas dynamics applications was verified by making a comparison with reference experimental and numerical results for the same flow configuration. The engineering analysis of the shock–column interaction was performed in the shear-stripping regime, where an acceptably accurate prediction of the interface deformation was achieved. Both column flattening and sheet shearing at the column equator were correctly reproduced, along with the water body drift.

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