Carbon and Sulfur Cycling by Microbial Communities in a Gypsum-Treated Oil Sands Tailings Pond
Carbon and Sulfur Cycling by Microbial Communities in a Gypsum-Treated Oil Sands Tailings Pond
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DOI：
10.1021/es1028487
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发表时间：
2011-01-15
影响因子：
11.4
通讯作者：
Gieg, Lisa M.
中科院分区：
文献类型：
--
作者：
Ramos-Padron, Esther;Bordenave, Sylvain;Gieg, Lisa M.
油砂尾矿库接收和储存从沥青提取中产生的固体和液体废物，并对其进行管理，以促进固体致密化和水循环。由于固体含量随着深度的增加而增加，池塘高度分层，但可能受到尾矿添加和移除以及微生物气体产生的对流的影响。我们将活性尾矿库中的微生物群落与微生物活动的关系表征为深度的函数，该尾矿库通常用石膏(CaSO4中心点2H(2)O)处理以加速致密化。16S rDNA基因序列的焦解测序表明，好氧表层的硫酸盐含量最高(6 Mm)，但没有检测到硫化物，其群落特征与池塘的其他部分截然不同。深层厌氧层主要是合营养菌(Pelotomaculum，Syntrous和Smithella spp.)，硫酸盐和硫还原细菌(SRB，Desulafapsa和Desulurivibrio spp.)，利用甲烷的乙酸盐和H-2，以及与碳氢利用或铁和硫循环有关的各种其他厌氧菌。硫酸盐还原速率最高的区域为硫酸盐还原速率最高的区域，在10~14MBS范围内SRB最为丰富。同样，确定为深度函数的最丰富的产甲烷菌和合营养体与波动的产甲烷速率密切相关。在实验室培养中，当硫酸盐的供应浓度达到池塘水平时，甲烷生成被抑制了近50%，这表明原位硫酸盐还原可以大大减少甲烷的排放。根据我们的数据，我们假设，由于硫化物在地表水中的高溶解度和氧化性，处理石膏的池塘中SRB活性导致的硫化物排放也是有限的。
Oil sands tailings ponds receive and store the solid and liquid waste from bitumen extraction and are managed to promote solids densification and water recycling. The ponds are highly stratified due to increasing solids content as a function of depth but can be impacted by tailings addition and removal and by convection due to microbial gas production. We characterized the microbial communities in relation to microbial activities as a function of depth in an active tailings pond routinely treated with gypsum (CaSO4 center dot 2H(2)O) to accelerate densification. Pyrosequencing of 16S rDNA gene sequences indicated that the aerobic surface layer, where the highest level of sulfate (6 mM) but no sulfide was detected, had a very different community profile than the rest of the pond. Deeper anaerobic layers were dominated by syntrophs (Pelotomaculum, Syntrophus, and Smithella spp.), sulfate- and sulfur-reducing bacteria (SRB, Desulfocapsa and Desulfurivibrio spp.), acetate- and H-2-using methanogens, and a variety of other anaerobes that have been implicated in hydrocarbon utilization or iron and sulfur cycling. The SRB were most abundant from 10 to 14 mbs, bracketing the zone where the sulfate reduction rate was highest. Similarly, the most abundant methanogens and syntrophs identified as a function of depth closely mirrored the fluctuating methanogenesis rates. Methanogenesis was inhibited in laboratory incubations by nearly 50% when sulfate was supplied at pond-level concentrations suggesting that in situ sulfate reduction can substantially minimize methane emissions. Based on our data, we hypothesize that the emission of sulfide due to SRB activity in the gypsum treated pond is also limited due to its high solubility and oxidation in surface waters.