Suja Laura Duran, Summers Stephen, Gutierrez Tony
Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt UniversityEdinburgh, UK.
Front Microbiol. 2017 Apr 21;8:676. doi: 10.3389/fmicb.2017.00676. eCollection 2017.
In this study we report the formation of marine oil snow (MOS), its associated microbial community, the factors influencing its formation, and the microbial response to crude oil in surface waters of the Faroe-Shetland Channel (FSC). The FSC is a subarctic region that is hydrodynamically complex located in the northeast Atlantic where oil extraction is currently occurring and where exploration is likely to expand into its deeper waters (>500 m). A major oil spill in this region may mirror the aftermath that ensued following the Deepwater Horizon (DWH) blowout in the Gulf of Mexico, where the massive influx of Macondo crude oil triggered the formation of copious quantities of rapidly sinking MOS and successional blooms of opportunistic oil-degrading bacteria. In laboratory experiments, we simulated environmental conditions in sea surface waters of the FSC using water collected from this site during the winter of 2015. We demonstrated that the presence of dispersant triggers the formation of MOS, and that nutrient amendments magnify this. Illumina MiSeq sequencing revealed the enrichment on MOS of associated oil-degrading (, , ) and EPS-producing (, , ) bacteria, and included major representation by and with putative oil-degrading/EPS-producing qualities. The formation of marine snow, in the absence of crude oil and dispersant, in seawater amended with nutrients alone indicated that the synthesis of bacterial EPS is a key factor in MOS formation, and the glycoprotein composition of the MOS aggregates confirmed that its amorphous biopolymeric matrix was of microbial (likely bacterial) origin. The presence of dispersants and crude oil with/without nutrients resulted in distinct microbial responses marked by intermittent, and in some cases short-lived, blooms of opportunistic heterotrophs, principally obligate hydrocarbonoclastic (, , , ) and EPS-producing (, , ) bacteria. Interestingly, members of the (principally the genus ) were strongly enriched by crude oil (with/without dispersant or nutrients), highlighting a putative importance for these organisms in crude oil biodegradation in the FSC. Our findings mirror those observed at DWH and hence underscore their broad relevance.
在本研究中，我们报告了海洋油雪（MOS）的形成、其相关的微生物群落、影响其形成的因素，以及法罗-设得兰海峡（FSC）表层水中微生物对原油的反应。FSC是一个亚北极地区，位于东北大西洋，水动力复杂，目前正在进行石油开采，并且勘探可能会扩展到其更深水域（>500米）。该地区的一次重大石油泄漏可能会反映出墨西哥湾深水地平线（DWH）井喷后随之而来的后果，在那里，大量马孔多原油的涌入引发了大量快速下沉的MOS的形成以及机会性石油降解细菌的连续繁殖。在实验室实验中，我们使用2015年冬季从该地点采集的水模拟了FSC海表水的环境条件。我们证明了分散剂的存在会触发MOS的形成，而营养物质的添加会放大这种作用。Illumina MiSeq测序揭示了与油降解（、、）和EPS产生（、、）相关细菌在MOS上的富集，并且包括具有假定油降解/EPS产生特性的和的主要代表。在仅添加营养物质的海水中，在没有原油和分散剂的情况下海洋雪的形成表明细菌EPS的合成是MOS形成的关键因素，并且MOS聚集体的糖蛋白组成证实其无定形生物聚合物基质是微生物（可能是细菌）来源。分散剂和原油（有/无营养物质）的存在导致了不同的微生物反应，其特征是机会性异养菌的间歇性（在某些情况下是短暂的）繁殖，主要是专性嗜烃菌（、、、）和EPS产生菌（、、）。有趣的是，（主要是属）的成员被原油（有/无分散剂或营养物质）强烈富集，突出了这些生物体在FSC原油生物降解中的假定重要性。我们的发现与在DWH观察到的结果相似，因此强调了它们的广泛相关性。
