Sediment microbial communities of a technogenic saline-alkaline reservoir

Abstract

Various natural saline and alkaline habitats have recently been widely investigated, but knowledge of anthropogenic habitats with more complex environmental conditions is still lacking. This research looks at the structure of microbial communities in 18 bottom sediment samples from a technogenic water body with saline and alkaline composition. The core samples were collected from 2 columns in the western and eastern parts of an artificial water body at the Verkhnekamskoe Salt Deposit (Russia). The microbial community structure was studied using high-throughput 16S rRNA gene sequencing. The bottom sediment composition (salinity, pH, and toxic element content) varies greatly with depth and laterally throughout the study area. The study found a considerable difference in bacterial community diversity between the 2 columns, but no considerable difference was found between the communities at various depths of the studied layers. Proteobacteria, Firmicutes, and Actinobacteria, which are common in both natural and artificial saline and alkaline environments, make up the majority of the bacteria found in the samples. Studies have shown that salinity and total alkalinity are the key factors influencing the formation of microbial communities. Ralstonia and Pseudomonas were the two most common genera in the sediment samples. These two genera are known for having high metabolic flexibility, which means they can survive in extreme environments and use a variety of carbon compounds as energy sources. The study also found that Ralstonia is indicator bacteria in samples with the highest concentrations of toxic elements compared to the other samples. A relatively high microbial diversity was discovered in the studied anthropogenic water reservoir despite the extreme alkaline and saline conditions, but it is considerably lower than that found in natural, less alkaline habitats. This research offers insight into the mechanisms behind microbial community formation in complex anthropogenic environments and covers key factors in microbial community distribution.