Effect of Aquaculture on the structure of sediment bacterial communities

In the past decade, the growth of the global seafood market has increased shellfish cultures worldwide. Increase of such cultures have led to significant decay of estuarine habitats. Prolonged shellfish cultures influences fluxes of greenhouse gases, increases organic matter decomposition and decreases oxygen in the water column. Such variation in physical factors can drive changes in sediment microbial communities that live in close association with these farm animals. This study therefore uses 16S sequencing to identify shifts in sediment bacterial compositions in response to different lengths of shellfish farming (control, 3, 5 and 7 years). We further relate such changes in bacterial compositions to sediment trace metal concentrations to investigate correlation patterns between them. Our results show an increase in species abundance in our 3 year site while the control, 5 and 7 year sites are relatively similar. Phylum level diversity for all sites are dominated by Proteobacteria, Bacteriodetes, Cyanobacteria, and Bacillariophyta. This study provides a first-hand account of 16S sequencing of bacterial community that exist in the top 1cm of soil sediments collected from shellfish farms with different duration of farming.