Seasonal distribution characteristics and environmental driving factors of bacterial communities in mangrove sediments of Ximen Island, Zhejiang Province

Mangrove forests, located at the interface of marine and terrestrial ecosystems in tropical and subtropical regions, harbor highly productive environments that support diverse microbial communities. These communities play a pivotal role in sustaining mangrove ecological functions and driving biogeochemical cycles. This study investigated the Ximen Island mangrove ecosystem in Zhejiang Province, employing high-throughput sequencing to systematically analyze the bacterial communities in surface sediments. We explored seasonal variations in bacterial diversity and assessed their correlations with environmental parameters. Results revealed that the sediment bacterial community in Ximen Island mangroves was dominated by Proteobacteria (39.11%), Desulfobacterota (10.02%), and Bacteroidota (9.17%). Among these, Proteobacteria and Desulfobacterota exhibited significant enrichment in spring, while Bacteroidota enriched in summer. Bacterial diversity indices exhibited significant seasonal dynamics: The richness index peaked in winter (2136 ± 235), while the Shannon index in spring (6.05 ± 0.15) was significantly lower than in autumn and winter (P