Functional response of microbial communities in lab-controlled oil-contaminated marine sediment†

Crude oil contamination is one of the biggest problems in modern society. As oil enters into contact with the environment, especially if the point of contact is a body of water, it begins a weathering process by mixing and spreading. This is dangerous to local living organisms’ communities and can impact diversity. However, despite unfavorable conditions, some microorganisms in these environments can survive using hydrocarbons as a nutrient source. Thus, understanding the local community dynamics of contaminated areas is essential. In this work, we analyzed the 16S rRNA amplicon sequencing and metatranscriptomic data of uncontaminated versus contaminated shallow marine sediment from publicly available datasets. We investigated the local population's taxonomic composition, species diversity, and fluctuations over time. Co-expression analysis coupled with functional enrichment showed us a prevalence of hydrocarbon-degrading functionality while keeping a distinct transcriptional profile between the late stages of oil contamination and the uncontaminated control. Processes related to the degradation of aromatic compounds and the metabolism of propanoate and butanoate were coupled with evidence of enhanced activity such as flagellar assembly and two-component system. Many enzymes of the anaerobic toluene degradation pathways were also enriched in our results. Furthermore, our diversity and taxonomical analyses showed a prevalence of the class Desulfobacteria, indicating interesting targets for bioremediation applications on marine sediment.