# Bacterial Diversity of Arctic Soils with Long-Standing Pollution by Petroleum Products and Heavy Metals

## TL;DR

This study explores how bacteria in Arctic soils adapt to long-term pollution from petroleum and heavy metals, showing their potential to help clean contaminated soil.

## Contribution

The study identifies specific bacterial genera and their metabolic capabilities in Arctic soils with chronic contamination.

## Key findings

- Bacterial phyla like Pseudomonadota and Bacillota increased with soil contamination.
- Isolated bacteria showed abilities to oxidize hydrocarbons and reduce iron.
- Strains were cold-tolerant and resistant to heavy metals like Cu(II), Ni(II), and Pb(II).

## Abstract

Long-standing and chronic soil pollution in the Polar Regions is the most persistent. Simultaneous contamination with petroleum products and heavy metals puts additional load on the soil microbial community. The purpose of this work was to determine the composition of prokaryotes in the soils of Mount Kaskama with long-standing contamination with petroleum products and heavy metals (Murmansk region, Russia) and outside this zone and the potential ability of bacteria to participate in the self-purification of these soils. Using high-throughput sequencing of 16S rRNA gene V3–V4 fragments, an increase in the proportion of bacteria of the phyla Pseudomonadota, Verrucomicrobiota, Cyanobacteriota, and Bacillota was shown with an increase in soil contamination. Bacteria of the genera Bacillus, Caballeronia, Cytobacillus, Paenibacillus, Paraburkholderia, Pseudomonas, and Rhodanobacter were isolated from soil samples. Bacteria of the genus Paenibacillus capable of hydrocarbon oxidation and iron reduction were isolated from the subsurface contaminated layers. Under aerobic conditions, Fe(II) oxidation by bacteria of the genus Pseudomonas and biodegradation of hydrocarbons by isolated bacteria are possible. The isolated strains grew at low temperatures, used diesel fuel components, and were resistant to Cu(II), Ni(II), and Pb(II). The data obtained indicates the adaptation of bacterial communities to environmental conditions and the ability to participate in the process of soil self-healing.