Tremblay Julien, Yergeau Etienne, Fortin Nathalie, Cobanli Susan, Elias Miria, King Thomas L, Lee Kenneth, Greer Charles W
National Research Council Canada, Montreal, Quebec, Canada.
INRS-Institut Armand-Frappier, Laval, Quebec, Canada.
ISME J. 2017 Dec;11(12):2793-2808. doi: 10.1038/ismej.2017.129. Epub 2017 Aug 11.
Application of chemical dispersants to oil spills in the marine environment is a common practice to disperse oil into the water column and stimulate oil biodegradation by increasing its bioavailability to indigenous bacteria capable of naturally metabolizing hydrocarbons. In the context of a spill event, the biodegradation of crude oil and gas condensate off eastern Canada is an essential component of a response strategy. In laboratory experiments, we simulated conditions similar to an oil spill with and without the addition of chemical dispersant under both winter and summer conditions and evaluated the natural attenuation potential for hydrocarbons in near-surface sea water from the vicinity of crude oil and natural gas production facilities off eastern Canada. Chemical analyses were performed to determine hydrocarbon degradation rates, and metagenome binning combined with metatranscriptomics was used to reconstruct abundant bacterial genomes and estimate their oil degradation gene abundance and activity. Our results show important and rapid structural shifts in microbial populations in all three different oil production sites examined following exposure to oil, oil with dispersant and dispersant alone. We found that the addition of dispersant to crude oil enhanced oil degradation rates and favored the abundance and expression of oil-degrading genes from a Thalassolituus sp. (that is, metagenome bin) that harbors multiple alkane hydroxylase (alkB) gene copies. We propose that this member of the Oceanospirillales group would be an important oil degrader when oil spills are treated with dispersant.
在海洋环境中，向溢油事故现场施用化学分散剂是一种常见做法，其目的是将油分散到水柱中，并通过提高油对能够自然代谢碳氢化合物的本地细菌的生物可利用性来促进油的生物降解。在溢油事件的背景下，加拿大东部近海原油和凝析油的生物降解是应对策略的一个重要组成部分。在实验室实验中，我们模拟了类似于溢油事故的条件，在冬季和夏季条件下分别添加和不添加化学分散剂，并评估了加拿大东部近海原油和天然气生产设施附近近表层海水中碳氢化合物的自然衰减潜力。通过化学分析来确定碳氢化合物的降解速率，并利用宏基因组分箱结合宏转录组学来重建丰富的细菌基因组，并估计它们的石油降解基因丰度和活性。我们的结果表明，在所有三个不同的石油生产地点，微生物种群在接触油、含分散剂的油和单独的分散剂后都发生了重要且迅速的结构变化。我们发现，向原油中添加分散剂提高了油的降解速率，并有利于来自一个含有多个烷烃羟化酶（alkB）基因拷贝的嗜盐栖热菌属（即宏基因组分箱）的石油降解基因的丰度和表达。我们认为，当用分散剂处理溢油时，这个海洋螺菌目菌群的成员将是一种重要的石油降解菌。
