Community assembly and co-occurrence network complexity of interstitial microbial communities in the Arctic (investigation of ciliates in the White Sea intertidal zone)

Toward an intensive understanding of sewer sediment prokaryotic community assembly and function

Prokaryotic communities play important roles in sewer sediment ecosystems, but the community composition, functional potential, and assembly mechanisms of sewer sediment prokaryotic communities are still poorly understood. Here, we studied the sediment prokaryotic communities in different urban functional areas (multifunctional, commercial, and residential areas) through 16S rRNA gene amplicon sequencing. Our results suggested that the compositions of prokaryotic communities varied significantly among functional areas. Desulfomicrobium, Desulfovibrio, and Desulfobacter involved in the sulfur cycle and some hydrolytic fermentation bacteria were enriched in multifunctional area, while Methanospirillum and Methanoregulaceae, which were related to methane metabolism were significantly discriminant taxa in the commercial area. Physicochemical properties were closely related to overall community changes (p < 0.001), especially the nutrient levels of sediments (i.e., total nitrogen and total phosphorus) and sediment pH. Network analysis revealed that the prokaryotic community network of the residential area sediment was more complex than the other functional areas, suggesting higher stability of the prokaryotic community in the residential area. Stochastic processes dominated the construction of the prokaryotic community. These results expand our understanding of the characteristics of prokaryotic communities in sewer sediment, providing a new perspective for studying sewer sediment prokaryotic community structure.

Distribution and co-occurrence networks of the bacterial community in sediment cores from the subtropical Daya Bay, China

The bacterial community plays an important role in biogeochemical cycles in marine sediment. However, little is known about the vertical profiles and co-occurrence patterns of bacterial community in sediment cores from the marine environment. In this study, five sediment cores were taken from a subtropical bay in China, heavily impacted by anthropogenic activities. The bacterial composition in sediment cores was investigated by using high-throughput sequencing of the 16S rRNA gene. A principal coordinates analysis and an adonis analysis of the operational taxonomic unit (OTU) compositions showed that spatial variation, rather than vertical variation, determined the bacterial structure in sediment cores. The bacterial complexity varied greatly across the five sediment cores, and the rare taxa played an important role in supporting the stability of the bacterial network. This study revealed that sediment properties and anthropogenic activities may induce a shift in the bacterial composition in sediment cores of a subtropical bay.