Different Assembly Patterns of Planktonic and Sedimentary Bacterial Community in a Few Connected Eutrophic Lakes

Abstract

The mechanism of bacterial community assembly has been the hot spot in the field of microbial ecology and it is difficult to quantitatively estimate the influences of different ecological processes. Here, a total of 23 pairs of planktonic and sedimentary samples were collected from five lakes in Wuhan, China. significant higher α-diversity (p < 0.001) and β-diversity (p < 0.001) of bacterial communities were observed in sediment than those in water. Some phylum had linear relationships with the comprehensive TSI (TSIc) by regression analysis. Non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA) revealed that the depth of water, NO3−-N, NH4+-N, PO43−, and CODcr were the key environmental variables in planktonic bacterial communities, whereas in sediment they were the depth, NO3−-N, and NH4+-N. Furthermore, variation partitioning analysis (VPA) showed that spatial and environmental factors could only explain 40.2% and 27.9% of the variation in planktonic and sedimentary bacterial communities, respectively. More importantly, null model analysis suggested that different assembly mechanisms were found between in water and in sediment with the fact that planktonic bacterial community assembly was mainly driven by dispersal limitation process whereas variable selection process played a vital role in that of sediment.

Human access and deterministic processes play a major role in structuring planktonic and sedimentary bacterial and eukaryotic communities in lakes

“…Previous studies ( Jiao et al, 2020 , 2021 ; Xia et al, 2022 ) have shown that bacterial sediment communities and water column communities were structured differently with homogeneous selection being more prominent in the water column in comparison to the sediment. This pattern was observed for both bacteria and eukaryotes although homogeneous selection was not the dominant process for bacteria in the water column.…”

“…Biological communities present within the sediments are also vital in many biogeochemical processes ( Forsberg, 1989 ). Studies investigating community patterns in both the water column and sediments are notably fewer and focused mostly on differences in bacterial communities between the two habitats ( Zeng et al, 2019 ; Jiao et al, 2020 , 2021 ; Xia et al, 2022 ).…”

“…They also highlighted that different biological taxonomic groups in the same lakes could be structured by different processes. While investigations are limited, lake sediment bacterial communities have been shown in a variety of Chinese lakes to be predominantly assembled by variable selection ( Zeng et al, 2019 ; Jiao et al, 2020 , 2021 ; Xia et al, 2022 ). In general, there is a pattern of homogeneous selection in the water column and variable selection in the sediment ( Zeng et al, 2019 ; Jiao et al, 2020 ; Xia et al, 2022 ).…”

“…While investigations are limited, lake sediment bacterial communities have been shown in a variety of Chinese lakes to be predominantly assembled by variable selection ( Zeng et al, 2019 ; Jiao et al, 2020 , 2021 ; Xia et al, 2022 ). In general, there is a pattern of homogeneous selection in the water column and variable selection in the sediment ( Zeng et al, 2019 ; Jiao et al, 2020 ; Xia et al, 2022 ). This is most likely due to variability in the sediment structure, as well as the accumulation of nutrients and pollutants from the catchment making the sediment more heterogenous.…”

Environmental filtering governs consistent vertical zonation in sedimentary microbial communities across disconnected mountain lakes

“…Our results agree with analyses of microbial communities within the surface sediments (first few cm) of lakes in other regions. In these studies, variable selection, driven by environmental differences, created differences among communities (Jiao et al, 2021; Pearman et al 2022, b; Xia et al, 2022; Yang et al, 2020; Zeng et al, 2019). Specifically, water nutrients, algal concentrations, and pH have been suggested to cause a strong selection of sediment bacteria (Jiao et al, 2021; Pearman, Adamson, et al, 2022; Zeng et al, 2019).…”