Spatiotemporal dynamics analysis of the gut microbiota composition in the Mactra veneriformis population in the intertidal zone of the Northern Yellow River Delta

Animal gut microbiota has been extensively studied, but there is relatively little research on the gut microbiota of wild bivalve mollusks, particularly regarding the spatiotemporal dynamics of their gut microbiota composition. This study investigated the spatiotemporal dynamics of the gut microbial community in Mactra veneriformis from the intertidal zone of the Northern Yellow River Delta across different seasons (spring, summer, autumn, winter) and tidal zones (middle tide zone, low tide zone) using high-throughput sequencing technology. The results indicated significant seasonal and tidal zone variations in the structure of the gut microbiota composition of M. veneriformis. At the phylum level, Proteobacteria and Firmicutes dominated in spring and summer, whereas Proteobacteria and Actinobacteriota were predominant in autumn and winter. ANOSIM analysis revealed significant differences in microbial composition between different seasons within the same tidal zone, but no significant difference was found between the middle and low tide zones only in spring. Co-occurrence network analysis further revealed a more complex microbial network structure in winter. Procrustes analysis demonstrated a highly significant correlation between the stomach content composition and the gut microbial community of M. veneriformis. This study elucidates the seasonal succession of the gut microbial community in M. veneriformis and its synergistic adaptation mechanism with dietary changes, providing a scientific basis for understanding the ecological adaptability of intertidal bivalves to environmental changes.