Characterization of Bacterial Diversity in Antarctic Soils Using 16S rRNA Gene Amplicon Sequencing

Abstract

Antarctic soils harbor highly specialized bacterial communities that perform essential functions in the functioning of polar ecosystems; however, the composition and structure of these communities remain poorly understood in many areas of Antarctica. The objective of this study was to characterize the diversity and structure of bacterial communities present in soils from four islands in the South Shetland Archipelago (Torre, Barrientos, Greenwich, and Dee) using 16S rRNA gene amplicon sequencing. Total genomic DNA was extracted from composite soil samples, followed by amplification of the 16S rRNA gene and sequencing on the Illumina MiSeq platform. Taxonomic classification allowed the sequences to be assigned from the domain level down to the species level, achieving classification rates between 98.47% and 99.39% at the domain level and between 57.39% and 65.88% at the species level. The bacterial communities were dominated by the phyla Bacillota, Pseudomonadota, Actinomycetota, and Bacteroidota, although variations in relative abundance patterns were observed among the composite samples analyzed. Alpha diversity indices revealed high taxonomic complexity, with greater species richness on Dee Island and greater evenness in Greenwich, highlighting differences in the diversity patterns observed among the composite samples analyzed. Taken together, these results expand our understanding of bacterial biodiversity in Antarctic soils and provide a baseline for future research in microbial ecology, biogeography, and the exploration of the biotechnological potential of microorganisms adapted to extreme environments.