Assessing the in situ bacterial diversity and composition at anthropogenically active sites using the environmental DNA (eDNA)

In this study, we identified the in situ bacterial groups and their community structure in coastal waters influenced by anthropogenic inputs. The use of environmental DNA (eDNA) and high throughput sequencing (HTS) were employed to derive accurate and reliable information on bacterial abundance. The V3 and V4 hypervariable regions of the 16S rRNA gene were amplified and the sequences were clustered into operational taxonomic units to analyze the site-specific variations in community composition. The percentage composition within the bacterial orders varied significantly among nearshore anthropogenic hotspots and offshore (5 km) samples. The microbial network constructed taking the bacterial abundance as nodes displayed strong positive and negative correlations within the bacterial families. Overall, the use of eDNA coupled with HTS is an incredible means for monitoring and assessing the abundance of bacterial communities and also serves as a biomonitoring tool to understand the degree of anthropogenic contamination in coastal waters.