Hydrocarbon degradation and response of seafloor sediment bacterial community in the northern Gulf of Mexico to light Louisiana sweet crude oil
Hydrocarbon degradation and response of seafloor sediment bacterial community in the northern Gulf of Mexico to light Louisiana sweet crude oil
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DOI：
10.1038/s41396-018-0190-1
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发表时间：
2018-10-01
期刊：
影响因子：
11
通讯作者：
Liu, Zhanfei
中科院分区：
文献类型：
--
作者：
Bacosa, Hernando P.;Erdner, Deana L.;Liu, Zhanfei
深水地平线（DWH）井喷导致2亿加仑石油泄漏到墨西哥湾，其中高达4.9%的石油沉积在海底。泄漏发生后，井口附近的石油碳氢化合物浓度立即很高，但在泄漏发生几年后又回到了背景水平。海底的微生物群落被认为对碳氢化合物的降解负有责任，然而，我们的知识主要是基于基因多样性调查和野外沉积物样品中的碳氢化合物浓度。在这里，我们研究了石油降解潜力和细菌群落的变化，通过用原油和石油和Corexit分散剂修正DWH站点附近的海底沉积物。在培养的前30天，多环芳烃的降解速度很快，而烷烃的降解速度较慢。随着烃类的降解，Colwelliaceae、Alteromonadaceae、Methylococales、Alcanivorax、Bacteriovorax和Phaeobacter的相对丰度显著增加。而原油降解菌的丰度随原油化学性质的变化而变化。随着油降解程度的增加，灯心草科植物的数量减少，而木芋科和甲基球藻科植物的数量则显著增加。我们从元基因组中收集了7个基因组，包括Colwellia， Alteromonadaceae, Rhodobacteraceae，新报道的Woeseia属和候选门NC10，它们都具有碳氢化合物降解的基因库。此外，油气处理过程中与油气降解相关的基因高度富集，表明油气已被生物降解，且本地微生物群对深海表层沉积物中溢油的自然衰减具有显著的潜力。
The Deepwater Horizon (DWH) blowout resulted in the deposition to the seafloor of up to 4.9% of 200 million gallons of oil released into the Gulf of Mexico. The petroleum hydrocarbon concentrations near the wellhead were high immediately after the spill, but returned to background levels a few years after the spill. Microbial communities in the seafloor are thought to be responsible for the degradation of hydrocarbons, however, our knowledge is primarily based upon gene diversity surveys and hydrocarbon concentration in field sediment samples. Here, we investigated the oil degradation potential and changes in bacterial community by amending seafloor sediment collected near the DWH site with crude oil and both oil and Corexit dispersant. Polycyclic aromatic hydrocarbons were rapidly degraded during the first 30 days of incubation, while alkanes were degraded more slowly. With the degradation of hydrocarbons, the relative abundances of Colwelliaceae, Alteromonadaceae, Methylococales, Alcanivorax, Bacteriovorax, and Phaeobacter increased remarkably. However, the abundances of oil-degrading bacteria changed with oil chemistry. Colwelliaceae decreased with increasing oil degradation, whereas Alcanivorax and Methylococcales increased considerably. We assembled seven genomes from the metagenome, including ones belonging to Colwellia, Alteromonadaceae, Rhodobacteraceae, the newly reported genus Woeseia, and candidate phylum NC10, all of which possess a repertoire of genes for hydrocarbon degradation. Moreover, genes related to hydrocarbon degradation were highly enriched in the oiled treatment, suggesting that the hydrocarbons were biodegraded, and that the indigenous microflora have a remarkable potential for the natural attenuation of spilled oil in the deep-sea surface sediment.