Composition and assembly of bacterial communities in surface and deeper sediments from aquaculture-influenced sites in Eastern Lake Taihu, China

Although aquaculture provides a stable and high-quality source of food, the environmental effects related to large-scale industrial aquacultural activities have raised concern. To identify the influence of aquacultural activities on sedimentary bacterial communities, we collected surface and deeper sediments from a series of sites subjected to varying intensities of aquacultural activities within Eastern Lake Taihu, China. The associated physicochemical properties were measured, and 16S rRNA gene sequencing was applied to determine the related bacterial communities in sediment. The diversity and composition of bacterial communities within the surface sediments differed significantly from those of the deeper sediment samples. Marked differences were also found between the surface sediments of the aquaculture-influenced and non-aquaculturally influenced sites. More importantly, phylogenetic structure analysis indicated that stochastic processes dominated the assembly of the bacterial communities; yet, the relative contribution of deterministic processes to bacterial community assembly was greater in the aquacultural zones than in the non-aquacultural zones. Furthermore, we identified total phosphorus (TP) as the most important factor driving the assembly of bacterial communities influenced by aquaculture in sediment. These findings provide useful information for ecological assessments and remediation strategies for aquaculture-influenced ecosystems.