Comparative analysis of bacterial community compositions between sediment and water in different types of wetlands of northeast China

Abstract

Although wetlands are one of the major ecosystems on the earth, information about the bacterial communities in different types of wetlands, especially in northeast China, has not yet been fully described. The aim of this study was to compare bacterial community compositions between sediment and water in different types of wetlands of northeast China. In this study, sediment and water samples were synchronously collected from different types of wetlands in northeast China. The bacterial communities were analyzed with Illumina MiSeq sequencing targeting the 16S rRNA gene. The results showed that the dominant phyla (relative abundance > 5%) across all sediment samples were Proteobacteria and Chloroflexi, while those across all water samples were Proteobacteria, Actinobacteria, and Bacteroidetes. Bacterial community composition was distinctly different among wetlands at the phylum and genus levels, and the indicator species for different sediment and water samples also varied greatly. The alpha diversity of bacterial community was higher in sediment samples than in water samples, and the lowest alpha diversity was detected in two coastal wetlands, both in sediment and in water samples. A heatmap analysis at the genus level and principal coordinate analysis revealed that all bacterial communities in sediment or in water samples were separated into distinct groups according to wetland type, and the communities in two coastal wetlands were highly similar to each other both in sediment and water samples, respectively. Bacterial communities in sediment were mainly affected by the available K content, followed by total C and total N, soil pH, etc., while in water, the communities were mainly affected by total P, total K, etc. The results revealed that bacterial community compositions between sediment and water samples were significantly different, and the communities in two coastal wetlands were more similar than those in other wetlands. The wetland sediment samples demonstrated higher community alpha diversity than the water samples, and alpha diversity was lowest in both the sediment and water of two coastal wetlands. Moreover, bacterial communities in sediment and water were driven by different environmental factors.