The Niger Delta is one of the most damaged ecosystems in the world, mainly due to petroleum contamination by oil exploration accidents. We investigated the natural attenuation potential of Niger Delta subsurface sediment samples for anaerobic hydrocarbon degradation using benzene as a model compound under iron-reducing, sulfate-reducing, and methanogenic conditions. Benzene was slowly mineralized under methanogenic and iron-reducing conditions using nitrilotriacetic acid (NTA)-Fe(III), or poorly crystalline Fe(III) oxyhydroxides as electron acceptors, analyzed by measurement of ¹³CO₂ produced from added ¹³C-labelled benzene. Highest mineralization rates were observed in microcosms amended with Fe(III) oxyhydroxides. The microbial communities of benzene-mineralizing enrichment cultures were characterized by next-generation sequencing of the genes coding for 16S rRNA and methyl coenzyme M reductase A (mcrA). Abundant phylotypes were affiliated to Betaproteobacteriales, Ignavibacteriales, Desulfuromonadales, and Methanosarcinales of the genera Methanosarcina and Methanothrix, illustrating that the enriched benzene-mineralizing communities were diverse and may contain more than a single benzene degrader. The diversity of the microbial communities was furthermore confirmed by scanning helium-ion microscopy which revealed the presence of various rod-shaped as well as filamentous microbial morphotypes.

尼日尔三角洲是世界上破坏最严重的生态系统之一，主要是由于石油勘探事故造成的石油污染。我们研究了尼日尔三角洲地下沉积物样品在还原铁，还原硫酸盐和产甲烷条件下使用苯作为模型化合物对厌氧烃降解的自然衰减潜力。使用次氮基三乙酸（NTA）-Fe（III）或结晶性较弱的Fe（III）羟基氧化氢氧化物作为电子受体，在产甲烷和铁还原的条件下将苯缓慢矿化，方法是通过测量添加¹³生成的¹³ CO ₂进行分析C标记的苯。在用羟基氧化铁（III）修正的微观世界中观察到最高的矿化速率。通过对16S rRNA和甲基辅酶M还原酶A（mcrA）进行编码的基因的下一代测序来表征苯矿化富集培养物中的微生物群落。Methanosarcina和Methanothrix属的Betaproteobacterialiales，Ignavibacteriales，Desulfuromonadales和Methanosarcinales属于丰富的系统型，这说明富集的苯矿化群落是多种多样的，并且可能包含多个单一的苯降解剂。通过扫描氦离子显微镜进一步证实了微生物群落的多样性，该显微镜揭示了各种杆状以及丝状微生物形态型的存在。