Publication Details

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Title (Primary) Vertical gradients in carbon flow and methane production in a sulfate-rich oil sands tailings pond
Author Stasik, S.; Wendt-Potthoff, K.;
Journal Water Research
Year 2016
Department SEEFO;
Volume 106
Language englisch;
POF III (all) T31;
Keywords Oil sands tailings ponds; Methanogenesis; Sulfate reduction; Inhibitors; Carbon transformation
UFZ wide themes RU2;
Abstract Oil sands tailings ponds are primary storage basins for tailings produced during oil sands processing in Alberta (Canada). Due to microbial metabolism, methane production contributes to greenhouse gas emissions, but positively affects tailings densification, which is relevant for operational water re-use. Depending on the age and depth of tailings, the activity of sulfate-reducing bacteria (SRB) may control methanogenesis due to the competition for substrates. To assess the depth-related impact of sulfate reduction on CH4 emissions, original tailings of two vicinal pond profiles were incubated in anoxic microcosms with/without molybdate as selective inhibitor of microbial sulfate reduction. Integrating methane production rates, considerable volumes of CH4 emissions (∼5.37 million L d−1) may be effectively prevented by the activity of SRB in sulfidic tailings between 3.5 and 7.5 m. To infer metabolic potentials controlling methanogenic pathways, a set of relevant organic acids (acetate, formate, propionate, butyrate, lactate) was added to part of the microcosms. Generally, organic acid transformation shifted with depth, with highest rates (305–446 μmol L−1 d−1) measured in fresh tailings at 5.5–7.5 m. In all depths, a transient accumulation of acetate revealed its importance as key intermediate during organic matter decomposition. SRB dominated the transformation of acetate, butyrate and propionate, but were not essential for lactate and formate turnover. Acetate as methanogenic substrate was important only at 13.5 m. At 1–7.5 m, methanogenesis significantly increased in presence of organic acids, most likely due to the syntrophic oxidation of acetate to CO2 by SRB and subsequent conversion to CH4.
ID 17954
Persistent UFZ Identifier
Stasik, S., Wendt-Potthoff, K. (2016):
Vertical gradients in carbon flow and methane production in a sulfate-rich oil sands tailings pond
Water Res. 106 , 223 - 231