Microbial and Functional Gene Dynamics in Long-Term Fermented Mariculture Sediment

The microorganisms of mariculture sediments are key to regulating and maintaining their ecosystem balance and have garnered research interest. Although the microbial composition and functional potential of mariculture sediments have been extensively explored in the past, the effects of long-term aquaculture on microbial communities and functional genes have been scarcely studied. Sediment samples from mariculture ponds with durations of 1 year, 6 years, and 10 years were collected in this study. A high-throughput metagenomic analysis was then conducted. The results showed that the sediments fermented for 1 year had the highest α-diversity, creating conditions for the divergence of functional microbial communities. Due to nutrient competition, long-term fermentation led to a decrease in both diversity and functional redundancy. Key functional groups exhibited different temporal succession patterns. In addition, long-term fermentation, especially fermentation over 10 years, resulted in significant differentiation of functional genes, particularly those related to carbon and nitrogen metabolism. This study reveals the distribution pattern of the microbiome during the natural fermentation process and its temporal coupling relationship with the functions of the pond ecosystem. It clarifies the dynamic evolution of functional genes, providing a theoretical basis for the sustainable management of mariculture.