Phylogenetic distance–decay patterns are not explained by local community assembly processes in freshwater lake microbial communities

Abstract

While water and sediment microbial communities exhibit pronounced spatio‐temporal patterns in freshwater lakes, the underlying drivers are yet poorly understood. Here, we evaluated the importance of spatial and temporal variation in abiotic environmental factors for bacterial and microeukaryotic community assembly and distance–decay relationships in water and sediment niches in Hongze Lake. By sampling across the whole lake during both Autumn and Spring sampling time points, we show that only bacterial sediment communities were governed by deterministic community assembly processes due to abiotic environmental drivers. Nevertheless, consistent distance–decay relationships were found with both bacterial and microeukaryotic communities, which were relatively stable with both sampling time points. Our results suggest that spatio‐temporal variation in environmental factors was important in explaining mainly bacterial community assembly in the sediment, possibly due lesser disturbance. However, clear distance–decay patterns emerged also when the community assembly was stochastic. Together, these results suggest that abiotic environmental factors do not clearly drive the spatial structuring of lake microbial communities, highlighting the need to understand the role of other potential drivers, such as spatial heterogeneity and biotic species interactions.

Linking ecological niches to bacterial community structure and assembly in polluted urban aquatic ecosystems

“…These findings indicate that bacterial community variations across distinct niches are, to a certain extent, modulated by environmental factors particularly dissolved oxygen levels and nutrient content (Qin et al, 2022;Shi et al, 2022). Abiotic factors, such as temperature and pH, are equally important in determining the bacterial assembly of different niches, which has been illustrated to have profound impacts on the survival, growth, and interactions of microorganisms (He et al, 2021;Gu et al, 2023). Consequently, further exploration of these abiotic factors is warranted in future studies to gain a deeper understanding of niche-mediated changes in the composition and functionality of microbial communities.…”