Spatiotemporal Dynamics of Bacterial Taxonomic and Functional Profiles in Estuarine Intertidal Soils of China Coastal Zone

Abstract Estuarine intertidal wetlands pertain to habitats with high productivity on Earth. Bacteria in estuarine intertidal soils regulate carbon (C), nitrogen (N) and sulfur (S) cycles. To gain insights into the ecological and metabolic modes possessed by bacteria in estuarine intertidal wetlands, we explored the spatial and seasonal variations of bacterial taxonomic composition, assembly processes, and ecological system functions in surface soils from China’s estuarine intertidal flats through shotgun metagenomic and 16S rRNA gene sequencing. Obvious spatiotemporal dynamic patterns in the bacterial community structure were identified, with more pronounced seasonal rather than spatial variations. Dispersion limitation was observed to act as a critical factor affecting community assembly, explaining approximately half of the total variation in bacterial community. Functional bacterial community structure exhibited a more significant latitudinal change than seasonal variability, highlighting that functional stability of the bacterial communities differed with their taxonomic variability. Identification of biogeochemically related links between C, N and S cycles in the soils showed the adaptive routed metabolism of the bacterial communities and the strong interactions between coupled metabolic pathways. Our study broadens the insights into the taxonomic and functional profiles of bacteria in China’s estuarine intertidal soils from various latitudes and helps us understand the effects exerted by environmental factors or climate-related variations on the ecological health and microbial diversity of estuarine intertidal flats.