Browsing by Author "Albakistani, Emad"

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    Methane Cycling and Methanotrophic Bacteria in Base Mine Lake, a Model End-Pit Lake in the Alberta Oilsands
    (2018-08-29) Albakistani, Emad; Dunfield, Peter F.; Voordouw, Gerrit; Gieg, Lisa Marie
    We studied methanotrophic bacteria over three years (2015 - 2018) in Base Mine Lake, Fort McMurray, Canada. The lake represents the first large scale demonstration of end-pit lake technology in the Alberta oilsands. 16S rRNA gene amplicon sequencing and measurement of methanotrophic rates were applied to evaluate the effect of seasonal changes on methanotrophic diversity and activity, and to understand the biogeochemical cycling of methane and oxygen. Based on 16S rRNA gene sequence relative abundance, the predominantly detected methanotrophic genera were Methylobacter/Crenothrix in the winter and Methylocaldum in the summer. Methanotrophs were most abundant in winter throughout the water column, and in summer at the bottom of the lake near the fluid fine tailings interface. Potential methanotrophic rates decreased over three years from 2015-2018.
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    Seasonal dynamics of methanotrophic bacteria in a boreal oil sands end-pit lake
    (2021-11-29) Albakistani, Emad; Nwosu, Felix; Furgason, Chantel; Haupt, Evan; Smirnova, Angela; Verbeke, Tobin; Lee, Eun-Suk; Kim, Joong-Jae; Chan, Amelia; Ruhl, Ilona; Sheremet, Andriy; Rudderham, Sarah; Lindsay, Matthew; Dunfield, Peter
    Base Mine Lake (BML) is the first full-scale demonstration end pit lake for the oil sands mining industry in Canada. We examined aerobic methanotrophic bacteria over all seasons for five years in this dimictic lake. Methanotrophs comprised up to 58% of all bacterial reads in 16S rRNA gene amplicon sequencing analyses (median 2.8%), and up to 2.7 × 104 cells mL−1 of water (median 0.5 × 103) based on qPCR of pmoA genes. Methanotrophic activity and populations in the lake water were highest during fall turnover, and remained high through the winter ice-covered period into spring turnover. They declined during summer stratification, especially in the epilimnion. Three methanotroph genera (Methylobacter, Methylovulum, and Methyloparacoccus) cycled seasonally, based on both relative and absolute abundance measurements. Methylobacter and Methylovulum populations peaked in winter/spring, when methane oxidation activity was psychrophilic. Methyloparacoccus populations increased in the water column through summer and fall, when methane oxidation was mesophilic, and also predominated in the underlying tailings sediment. Other, less abundant genera grew primarily during summer, possibly due to distinct CH4/O2 microniches created during thermal stratification. These data are consistent with temporal and spatial niche differentiation based on temperature, CH4 and O2. This pit lake displays methane cycling and methanotroph population dynamics similar to natural boreal lakes. Importance statement: The study examined methanotrophic bacteria in an industrial end pit lake, combining molecular DNA methods (both quantitative and descriptive) with biogeochemical measurements. The lake was sampled over 5 years, in all four seasons, as often as weekly, and included sub-ice samples. The resulting multi-season and multi-year dataset is unique in its size and intensity, and allowed us to document clear and consistent seasonal patterns of growth and decline of three methanotroph genera (Methylobacter, Methylovulum, and Methyloparacoccus). Laboratory experiments suggested that one major control of this succession was niche partitioning based on temperature. The study helps to understand microbial dynamics in engineered end-pit lakes, but we propose that the dynamics are typical of boreal stratified lakes, and widely applicable in microbial ecology and limnology. Methane oxidising bacteria are important model organisms in microbial ecology, and have implications for global climate change.