Composition of Bacterial Communities in Oil-Contaminated Bottom Sediments of the Kamenka River

The Kamenka River flows through the territory of the Kokuyskoye gas and oil field located in Perm krai. Despite the absence of oil-producing facilities in the immediate vicinity of the river, oil hydrocarbons were found in the waters and bottom sediments at a concentration of 2445–25800 mg/kg. The composition of microbial communities of bottom sediments of the Kamenka River located at the source and along the river was studied. Using the methods of high-performance sequencing and bioinformatic data processing, it was established that the main share of microbial communities is represented by bacteria of the phylum Proteobacteria (16.7–30.3%), as well as the phyla Actinobacteriota, Bacteroidota, Bdellovibrionota, Campilobacterota, Chloroflexi, Cyanobacteria, Deferribacterota, Desulfobacterota, Firmicutes, Gemmatimonadota, Methylomirabilota, Myxococcota, Nitrospirota, Patescibacteria, Planctomycetota, Spirochaetota, Synergistota, Thermotofota, and Verrucomicrobiota. The values of the Shannon index for the studied communities are directly correlated with the concentration of petroleum hydrocarbons in bottom sediments. The phylum Proteobacteria in all communities is represented by the classes Alphaproteobacteria and Gammaproteobacteria, among which representatives of the families Rhodobacteriaceae and Comamonadaceae dominate. When identifying to the genus, it was found that the main share in the Comamonadaceae family is made up of bacteria of the genus Hydrogenophaga . It should be noted that bacteria of the genus Pseudomonas (class Gammaproteobacteria) were found only in the microbiocenosis of bottom sediments, characterized by the highest concentration of petroleum hydrocarbons.