Microbiota Structure of Swimming Crabs from a Mercury-Impacted Estuary in Southeastern Brazil and Its Association with Abiotic Parameters

This project investigates the microbial community structure associated with swimming crabs collected from a heavily anthropogenically impacted estuary in Southeastern Brazil. The study integrates high throughput 16S rRNA gene sequencing with environmental and chemical analyses to evaluate the influence of abiotic parameters and mercury contamination on host associated microbiota composition.Samples were obtained from crabs collected in estuarine zones exhibiting distinct physicochemical gradients. Total DNA was extracted and subjected to paired end Illumina sequencing targeting the V3 V4 region of the 16S rRNA gene. Sequence data were processed using a standardized QIIME2 pipeline, including denoising with DADA2, amplicon sequence variant inference, taxonomic classification, phylogenetic reconstruction, and diversity analyses.Microbial diversity metrics were calculated to assess intra and inter sample variation. Community composition was evaluated at multiple taxonomic levels, and correlation analyses were conducted to explore associations between microbial taxa, abiotic factors, and mercury concentrations. Statistical analyses included non parametric testing and false discovery rate correction to account for multiple comparisons.This dataset provides a comprehensive characterization of estuarine crab associated microbiota under metal stress conditions and contributes to understanding microbial ecological responses to environmental contamination. The data may support future studies in marine microbial ecology, environmental monitoring, ecotoxicology, and host microbiome interactions in coastal ecosystems.All raw sequencing reads generated in this project are deposited in the Sequence Read Archive and are linked to corresponding environmental metadata.