Centennial trends in human and climate influences on sediment-associated microorganisms in an oligotrophic lake

Microorganisms in lake ecosystems exhibit sensitive and dynamic changes in response to human activities and climate change. However, studies correlating microbial communities with anthropogenic changes over a century-long timescale are currently lacking. In this study, DNA extracted from sediments and lake sediment environmental proxy analyses were employed to reconstruct a centennial-scale time series of prokaryotic and microeukaryotic community changes, revealing distinct differences in their evolutionary patterns. The results indicated that the heterogeneity of the prokaryotic community was increasing, and the community assembly was consistently influenced by both deterministic and stochastic processes. Microeukaryotes showed significant fluctuations in the relative abundance of the dominant species, a continuous increase in alpha diversity, and stochastic processes as a key mechanism of community assembly. In addition, climate and human activities were identified as key factors influencing microbial communities. It was found that the dynamics of the prokaryotic community were influenced by both biotic and environmental factors, whereas microeukaryotic population dynamics were particularly influenced by external factors. In general, changes in the watershed environment significantly impacted microbial evolutionary patterns, providing new insights into the evolution of lake ecosystems and offering strong support for future lake management and conservation efforts.