Coastal sediments are considered to be final receptacles for organic and inorganic contaminants. Characterizing those sediments and assessing their biodegradation potential have become a great challenge in recent years. In this study, the chemical composition, including the content in polycyclic aromatic hydrocarbons, the microbial community abundance and diversity (using culture-independent approaches targeting 16S rRNA genes), and the aerobic/anaerobic biodegradation potential of coastal sediments collected in the Sfax coastal area (Gulf of Gabès, Southern Mediterranean Sea) were investigated. The highest concentration of total polycyclic aromatic hydrocarbons (981 µg kg⁻¹ dw) was recorded in Sidi Mansour harbor sediment, emphasized pyrogenic and petrogenic hydrocarbon sources. Organic matter, including total organic carbon, and the ultimate aerobic biodegradability, with 30% as the highest value in Sidi Salem channel sediment, were in a positive accordance with bacterial communities assigned within Actinobacteria, Clostridia and Flavobacteria classes. The correlation noticed between Thermocladium and Thermogladius genera and sulfate content explained that Sidi Mansour and PK4 sediments are located in terrestrial acid–sulfate areas. The highest cumulative methane produced with Marseille inoculum and Tunisian inoculum was recorded in Sidi Salem sediment and strongly correlated with methanogens among Methanobacteria, Methanococci and Methanomicobia classes showing the presence of industrial and municipal sources. The bioavailability of low and moderate polycyclic aromatic hydrocarbons in the current study may explain the occurrence of Methanobacterium which positively correlated with the anaerobic biodegradability using Tunisian inoculum with 50% as the highest value in Sidi Mansour sediment.

沿海沉积物被认为是有机和无机污染物的最终容器。近年来，表征这些沉积物并评估其生物降解潜力已成为一项巨大挑战。在这项研究中，化学成分包括多环芳烃的含量，微生物群落的丰度和多样性（使用针对16S rRNA基因的与培养无关的方法）以及在Sfax沿海地区收集的沿海沉积物的好氧/厌氧生物降解潜力。 （加贝斯湾，地中海南部）进行了调查。总多环芳烃的最高浓度（981 µg kg ^-1 dw）记录在西迪曼苏尔港的沉积物中，重点是热成因和岩石成因的烃源。有机物（包括总有机碳）和最终有氧生物降解性（在Sidi Salem通道沉积物中的最高值为30％）与放线菌属，梭菌属和黄杆菌属中的细菌群落呈正相关。注意到之间的相关性Thermocladium和Thermogladius属和硫酸盐含量解释，思迪曼苏尔和PK4沉积物位于地面酸硫酸盐区域。马赛接种物和突尼斯接种物产生的最高甲烷累积量记录在西迪塞勒姆沉积物中，并且与甲烷生成物之间的相关性很强。甲烷细菌，甲烷球菌和甲烷菌病类别显示了工业和市政来源的存在。当前研究中低和中度多环芳烃的生物利用度可能解释了甲烷菌的发生，该菌与突尼斯接种物的厌氧生物降解能力呈正相关，突尼斯接种物以西迪曼苏尔沉积物中的最高值为50％。