清水河流域典型水库沉积物细菌群落结构的季节性变化特征OA

[Objective]This study reveals the seasonal evolution characteristics and main environmental influencing factors of bacterial communities in reservoir sediments in arid and semi-arid regions,thereby providing a theoretical basis for microbial ecology research in artificial water bodies and regional reservoir ecological management.[Methods]Eight typical reservoirs in the Qingshui River Basin,Ningxia,were selected as the research objects.Sediment samples were collected in May(normal-flow season),July(wet season),and December(dry season)of 2022.Based on 16S rRNA gene high-throughput sequencing results and sediment physicochemical parameters,this study revealed the seasonal dynamics,assembly processes,stability of bacterial communities,and their relationships with environmental factors using methods such as principal coordinates analysis(PCoA),neutral community model,and co-occurrence network analysis.[Results](1)The diversity and richness of sediment bacterial communities exhibited significant seasonal differences,with the overall pattern of May>July>December,and the differences in community structure between months were significant(p<0.05).(2)The bacterial communities were primarily dominated by Proteobacteria,Bacteroidota,and Firmicutes,and their relative abundance showed significant seasonal fluctuations.(3)The neutral model indicated that stochastic processes dominated bacterial community assembly,but their influence weakened over time.(4)Co-occurrence network analysis showed that the bacterial community network in July exhibited the highest complexity and connectivity,while the networks in May and December had stronger modularity and stability.(5)Ammonium nitrogen(NH4+-N),available phosphorus(AP),pH,and electrical conductivity(EC)were the main environmental factors influencing bacterial community structure,with NH4+-N showing positive correlations with both the Shannon and Chao1 diversity indices.[Conclusion]The diversity and structure of bacterial communities in the reservoir sediments of the Qingshui River basin show significant seasonal differentiation.Their community assembly is primarily driven by stochastic processes,but the effect of environmental filtering strengthens with seasonal changes.Ammonium nitrogen is a key factor driving changes in community diversity and richness.