Insights into community profiles, environmental influence, and assembly mechanisms of oyster-associated bacteriome from Yueqing Bay, China via absolute quantitation by metabarcoding

Background Oyster populations create new habitats, maintain productivity, improve water quality by removing excess nutrients in coastal environments, and provide a source of animal protein. More importantly, their associated bacteriome is likely a primary contributor to these ecological functions. However, the community profiles, assembly mechanisms of oyster-associated bacteria, and their interaction with the surrounding environment remain poorly understood. Methods In this study, 24 oysters were collected from four typical oyster farming sites from Yueqing Bay, China, and subjected to spike-in absolute high-throughput 16S rRNA amplicon sequencing and subsequent bioinformatic analysis. Results and discussion The results show that the pan-bacteriome of oysters from Yueqing was dominated by Proteobacteria at the phylum and Vibrio at the genus level, which were the most prevalent and abundant bacteria. Moreover, the structure of the oyster bacteriome from different sampling sites revealed significant geographic differences. These variations were found to be significantly correlated with the physicochemical properties, such as salinity, total nitrogen, ammoniacal nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 − -N), etc. Importantly, analyses of the neutral community model (NCM) and null model revealed that stochasticity dominated the assembly of the oyster bacteriome. Such ecological processes may contribute to maintaining the diversity and stability of the oyster bacteriome. Conclusion Collectively, the findings of this study enhance our understanding of the patterns of farmed oyster bacteriome across different environmental conditions and their underlying assembly mechanisms, thereby providing essential insights for evaluating coastal ecosystem health and valuable guidance for sustainable oyster farming practices.