Kay_Isme2016_poster

Kay_Isme2016_poster

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  Figure 2. Left:Microbial cell counts from day -1 (pre CH4 injection) to day 253. The stable or increasing cell numbers at 2 m and 4 m depth was indicative of an active methanotrophic population. Combined effects of CH4 concentration (Figure 3) and anoxic conditions possibly contributed to the sharp decline in cell numbers at 6 m. No visible change was observed at 8 m depth. Middle: Green enhanced fluorescent image from 2 m depth of various cell morphologies at day -1. Right: Day 253 sample image showing dominance of large coccoid cells. The morphology and cell diameter is consistent with Methylococcaceae and support their relative abundance in Figure 1 as a direct result of CH4 release.Figure 3. Contour plot by depth at 113 days and 245 days showing CH4 migration and persistence in the aquifer. Dashed line; CH4 injection horizon, Blue arrow; groundwater flow direction, Diamond in green box; monitoring well for this study. Figure1. Left: Domain level taxonomic distribution. The relative sequence abundance of methane oxidizers (red), other Bacteria (blue) and Archaea (green) are displayed per depth. Right: Relative sequence abundance of bacterial taxa in the monitoring well. CH4 was injected from day 0 to day 72 (dashed line). Methylococcaceae are shown in red, Methylophilaceae in orange, sulfate reducers in yellow. Other taxa possibly involved in the cycling of sulfur and iron are shown in blue and brown, respectively. Methane injection strongly and persistently disturbed indigenous microbial communities with no sign of recovery after 254 days. Microbial community response to fugitive methane in groundwater Olukayode Kuloyo1 * ([email protected]) Collaborators: Emil Ruff1 , Bernhard Mayer1 , Aaron Cahill2 , Beth Parker2 , Colby Steelman2 , John Cherry2 , Ulrich Mayer3 , Olenka Forde3 , Cathryn Ryan1 , Bethany Ladd1 , Sara Cho1 , and Marc Strous1 1 Department of Geoscience, University of Calgary, Canada 2 G360 Centre for Applied Groundwater Research, University of Guelph, Ontario, Canada 3 Department of Earth, Ocean and Atmospheric Science, University of British Colombia, British Colombia, Canada Abstract The expansion of unconventional natural gas extraction (e.g. from shale) has raised concerns over potential impacts of fugitive methane migration on shallow groundwater. To provide direct insight into the effect of methane (CH4) and the microbial processes involved in CH4 removal from contaminated aquifers, we performed metagenomic and microbiological analyses of groundwater from multi-level depths during a controlled methane-release experiment at a research aquifer in Borden, Ontario.  Methane (51,350 liters) was injected at 4.5 m and 9 m depth into the aquifer over a 72-day period  Groundwater from multi-level monitoring wells was sampled for geochemical and molecular analyses over 254 days  Samples were serial-filtered through 0.22 mμ and 0.1 m membrane filters for DNAμ extraction  The V3-V4 region of 16S rRNA gene was amplified and sequenced using Illumina Miseq platform  Microbial cells were visualized and enumerated using DAPI stain under a fluorescent microscope Materials and Methods Microbial community profile of groundwater monitoring well site 2 m 4 m 6 m 8 m Depth (m) 113 Days 245 Days Horizontal Distance (m) CH4 (mg/l)  CH4 release caused microbial community shift and strongly stimulated the growth of methanotrophs (up to 64% relative abundance)  Methane oxidation decreased with depth due to oxygen-limitation. Anaerobic methanotrophs were undetected.  Low microbial cell numbers and persistent CH4 after 8 months suggested that methane oxidation was relatively ineffective in the aquifer.  Metagenomic analyses are an important and complementary tool to geochemical and isotopic techniques for assessing the fate of CH4 in contaminated shallow groundwater. Key Findings Microbial cell numbers Methane Plume Persistence Day -1 Day 253