Warming reduces bacterial diversity and stability in Lake Bosten.

Understanding the effects of warming on bacterial communities is essential for predicting microbial responses to climate change in aquatic ecosystems. However, the mechanisms through which warming influences bacterial diversity and stability in lake ecosystems remain poorly understood. To address this gap, we conducted a mesocosm experiment in Lake Bosten, a climate change hotspot, with three temperature scenarios (26 °C, 29 °C, and 32 °C), and investigated bacterial diversity, community composition, potential functions, and stability. Our findings revealed that temperature, time, and their interactions significantly reduced bacterial α-diversity (two-way ANOVA: P < 0.05). Warming altered bacterial potential metabolic functions, with decreases in methanotrophy and methylotrophy and increases in phototrophy and photoheterotrophy. Warming also increased species replacement within bacterial communities, indicating a dynamic shift in community composition. Network analysis indicated heightened complexity under higher temperatures but also a decrease in bacterial stability, evidenced by higher average variation degree (AVD), increased vulnerability, and reduced robustness. Overall, our study highlights the profound effects of warming on the ecological dynamics of lake bacterial communities, underscoring the need for further research to understand and mitigate the impacts of global climate change on aquatic ecosystems.