Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau Cedex, France.
Université de Pau et des Pays de l'Adour, Bâtiment IBEAS, BP 1155, 64013, Pau Cedex, France.
Environ Sci Pollut Res Int. 2015 Oct;22(20):15248-59. doi: 10.1007/s11356-015-4373-2. Epub 2015 Apr 7.
The present study aimed to examine whether the physical reworking of sediments by harrowing would be suitable for favouring the hydrocarbon degradation in coastal marine sediments. Mudflat sediments were maintained in mesocosms under conditions as closer as possible to those prevailing in natural environments with tidal cycles. Sediments were contaminated with Ural blend crude oil, and in half of them, harrowing treatment was applied in order to mimic physical reworking of surface sediments. Hydrocarbon distribution within the sediment and its removal was followed during 286 days. The harrowing treatment allowed hydrocarbon compounds to penetrate the first 6 cm of the sediments, and biodegradation indexes (such as n-C18/phytane) indicated that biodegradation started 90 days before that observed in untreated control mesocosms. However, the harrowing treatment had a severe impact on benthic organisms reducing drastically the macrofaunal abundance and diversity. In the harrowing-treated mesocosms, the bacterial abundance, determined by 16S rRNA gene Q-PCR, was slightly increased; and terminal restriction fragment length polymorphism (T-RFLP) analyses of 16S rRNA genes showed distinct and specific bacterial community structure. Co-occurrence network and canonical correspondence analyses (CCA) based on T-RFLP data indicated the main correlations between bacterial operational taxonomic units (OTUs) as well as the associations between OTUs and hydrocarbon compound contents further supported by clustered correlation (ClusCor) analysis. The analyses highlighted the OTUs constituting the network structural bases involved in hydrocarbon degradation. Negative correlations indicated the possible shifts in bacterial communities that occurred during the ecological succession.
本研究旨在探讨耕翻是否适合促进沿海海洋沉积物中烃类的降解。在尽可能接近自然环境条件下的中观模型中保持泥滩沉积物，这些条件包括潮汐循环。沉积物受到乌拉尔混合原油的污染，其中一半进行了耕翻处理，以模拟表层沉积物的物理重塑。在 286 天的时间里，跟踪了沉积物中烃类的分布及其去除情况。耕翻处理允许烃类化合物渗透到沉积物的前 6 厘米，生物降解指数（如 n-C18/phytane）表明，生物降解在未处理对照中观模型中观察到的时间提前了 90 天。然而，耕翻处理对底栖生物有严重影响，大大降低了大型动物的丰度和多样性。在耕翻处理的中观模型中，通过 16S rRNA 基因 Q-PCR 确定的细菌丰度略有增加；16S rRNA 基因的末端限制性片段长度多态性（T-RFLP）分析显示出独特而特定的细菌群落结构。基于 T-RFLP 数据的共生网络和典范对应分析（CCA）表明了细菌操作分类单元（OTUs）之间的主要相关性，以及 OTUs 与烃类化合物含量之间的关联，聚类相关（ClusCor）分析进一步支持了这一点。这些分析突出了构成网络结构基础的参与烃类降解的 OTUs。负相关表明在生态演替过程中可能发生了细菌群落的转变。
