Unveiling the Unique Microbial Diversity of Dhala Impact Crater: Comparative Insights with Crater and Non-crater Soil

The Dhala Impact Crater, the largest crater in Southeastern Asia, presents a unique environment for studying microbial diversity, though its soil bacterial composition remains largely unexplored. Using 16S rRNA gene amplicon sequencing on an Illumina MiSeq platform to characterize the bacterial communities of four soil samples within the crater. A total of 2,368,428 high-quality sequences were obtained, and operational taxonomic units (OTUs) were defined at 97% sequence similarity. The dominant bacterial phyla were Proteobacteria (syn. Pseudomonadota), Firmicutes (syn. Bacillota), Actinobacteria (syn. Actinomycetia), and Bacteroidetes (syn. Bacteroidia), with clear differences in community composition and alpha diversity among sampling sites. Principal component analysis (PCA) revealed marked between-sample variation, particularly disturbed sites. Functional prediction using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) suggested enrichment of genes related to oxidative phosphorylation, nitrogen metabolism, motility, and secretion systems. Comparative analyses showed that the Dhala Impact Crater shares dominant phyla with Lonar Lake Crater and natural agricultural soils while maintaining a distinct compositional signature. This study provides the first comprehensive overview of the bacterial diversity and predicted functional potential of Dhala Impact Crater soils and establishes a baseline for future work on the role of microbial communities in impact-affected terrestrial environments.