High heterogeneity of bacterioplankton community shaped by spatially structured environmental factors in West Lake, a typical urban lake in eastern China.

Elucidating the bacterioplankton spatial distribution patterns and its determinants is a central topic in ecological research. However, research on the distribution patterns of bacterioplankton community composition (BCC) within a small-sized, highly dynamic freshwater lake remains unclear. In this study, we collected surface water samples from West Lake to investigate the spatiotemporal variation of BCC by 16S rRNA gene high-throughput sequencing. Clear spatial heterogeneity in BCC was identified both in summer and winter. The relatively high abundant taxa exhibited greater correlations with environmental factors and other abundant species in summer than in winter. Variation partitioning analysis was used to unravel the relative importance of environmental factors and spatial processes and further explore the underlying mechanism of BCC successions. Our results showed the predominant shared effect of environmental and spatial factors on BCC in summer (68.41%) and winter (57.37%), indicating that spatially structured environmental factors were the key determinants of structuring BCC spatial heterogeneity in West Lake in the two seasons. Furthermore, environmental factors alone explained a higher proportion of the variation in summer whereas spatial factors explained a higher proportion in winter. These divergences may be related to seasonal environmental changes and anthropogenic disturbances. Our study provided knowledge on BCC spatial heterogeneity in small freshwater habitats and their underlying determinants in different seasons.