Wetlands provide unique ecological functions such as nutrient cycling, sediment accumulation, pollution filtration, and erosion control. Researching wetland ecosystems can help us better understand the functional linkages between terrestrial and aquatic systems. Estuaries are among the wetland ecosystems that are fragile, sensitive and vulnerable to pressure and disturbances from both natural processes and human activities. The estuarine ecosystem is one of the most important natural ecosystems on Earth, and contributes substantially to human survival and development. The Yellow River Estuary is the second largest estuary in China. Microbial communities have an essential role in the material cycle and energy flow of estuarine ecosystems. Our study aimed to i) elucidate the spatial community profile of intertidal sedimental bacteria and archaea in the Yellow River Estuary, ii) investigate any possible correlation between the intertidal sedimental microorganisms, and the environmental abiotic factors (such as total nitrogen, sediment diameter, heavy metal etc.). iii) evaluate potential functions of intertidal microorganisms of the Yellow River Estuary. We investigated the spatial patterns, co-occurrence networks, function prediction and driving factors of bacterial and archaeal communities in intertidal sediments of the Yellow River Estuary from June to July 2019. This was performed using the Illumina MiSeq platform for high-throughput sequencing of the 16S rRNA gene. The results showed that Proteobacteria, Bacteroidetes, Chloroflexi, and Planctomycetes were the dominant bacterial phyla, and Nanoarchaeaeota, Euryarchaeota and Thaumarchaeota were the dominant archaeal phyla in intertidal sediments from the Yellow River Estuary. Alpha diversity and beta diversity analysis revealed that spatial patterns of microorganisms in intertidal sediments from the Yellow River Estuary were significantly different (p <0.5). The random-forest: LKJR based differential biomarker analysis discovered spatial abundance variation of some genera. Environmental factors, including temperature, silty clay content, sediment median diameter and heavy metals influenced the bacterial community structure significantly. Meanwhile, the archaeal community was positively correlated with temperature, salinity and silty clay content. Linking the correlation between environmental factors and bacteria and co-occurrence pattern analysis together, we found that bacteria with the same effect as heavy metals were present in the same modules. The annotated results of FAPROTAX indicated a link between Pseudomonas and plastic degradation and Cycloclasticus had a role in petroleum bioremediation. Overall, our study presents a detailed outline of the spatial patterns of microbial communities in the Yellow River Estuary, and provides insights to better understand wetland ecological health of the intertidal zones from a microbial perspective.

high-throughput sequencing, co-occurrence network, function prediction, bacteria, archaea, Yellow River Estuary