The (DWH) oil spill significantly impacted salt marsh ecosystems, with numerous repercussions observed in the subsequent years. However, the long-term effects of chronic oil exposure on soil microbial communities remain unexplored. This study, conducted in 2018, aimed to identify how the legacy of heavy oiling from the DWH spill in 2010 influenced the soil microbial community. We surveyed vegetation and soil variables while simultaneously employing high-throughput 16s rRNA gene sequencing to examine microbial communities in soils across 21 marsh sites that exhibited varying degrees of initial oil contamination following the DWH incident. The effects of these variables, including geographic location, on taxonomic and phylogenetic metrics of community composition were disentangled using variance partitioning analysis and permutational ANOVA. Results showed a strong and significant longitudinal trend in microbial community composition that was partially confounded with degree of initial oil exposure and contemporary vegetation biomass. However, significant indicator species for heavily oiled sites included oil-degrading bacteria, and there were significant differences in microbial community composition among marshes that received variable levels of initial oiling after controlling for this spatial effect. The level of soil petroleum residues that remained in 2018 had significant explanatory power for community composition after controlling for location, whereas the effects of vegetation biomass were largely confounded with longitude. Collectively, our results indicate that persistent oil pollution as well as unidentified spatial processes, possibly associated with spill-induced alterations in erosion or wave dynamics, played a role in structuring soil microbial communities within this ecosystem.

中文翻译：

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深水地平线漏油事件八年后，空间异质性和石油污染构成了美国路易斯安那州巴拉塔里亚湾盐沼中的土壤微生物群落

(DWH) 石油泄漏严重影响了盐沼生态系统，并在随后的几年中观察到了许多影响。然而，长期接触石油对土壤微生物群落的长期影响仍有待探索。这项研究于 2018 年进行，旨在确定 2010 年 DWH 泄漏造成的重油残留如何影响土壤微生物群落。我们调查了植被和土壤变量，同时采用高通量 16s rRNA 基因测序来检查 21 个沼泽地土壤中的微生物群落，这些沼泽地在 DWH 事件后表现出不同程度的初始石油污染。使用方差分配分析和排列方差分析来阐明这些变量（包括地理位置）对群落组成的分类学和系统发育指标的影响。结果显示，微生物群落组成存在强烈且显着的纵向趋势，该趋势与初始石油暴露程度和当代植被生物量部分混杂。然而，严重石油污染地点的重要指示物种包括石油降解细菌，并且在控制这种空间效应后，初始石油污染程度不同的沼泽中的微生物群落组成存在显着差异。在控制位置后，2018年残留的土壤石油残留物水平对群落组成具有显着的解释力，而植被生物量的影响在很大程度上与经度混杂。总的来说，我们的结果表明，持续的石油污染以及未知的空间过程（可能与泄漏引起的侵蚀或波浪动力学变化有关）在构建该生态系统内的土壤微生物群落方面发挥了作用。