Lake Uchum is a newly defined meromictic lake in Siberia with clear seasonal changes in its mixolimnion. This study characterized the temporal dynamics and vertical profile of bacterial communities in oxic and anoxic zones of the lake across all four seasons: October (autumn), March (winter), May (spring), and August (summer). Bacterial richness and diversity in the anoxic zone varied widely between time points. Proteobacteria was the dominant bacterial phylum throughout the oxic and anoxic zones across all four seasons. Alphaproteobacteria (Loktanella) and Gammaproteobacteria (Aliidiomarina) exhibited the highest abundance in the oxic and anoxic zone, respectively. Furthermore, there was a successional shift in sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria in the anoxic zone across the seasons. The most dominant SRB, Desulfonatronovibrio sp., is likely one of the main producers of hydrogen sulfide (H₂S) and typically accumulates the most H₂S in winter. The representative anoxygenic phototrophic bacterial group in Lake Uchum was purple sulfur bacteria (PSB). PSB were dominant (60.76%) in summer, but only had 0.2–1.5% relative abundance from autumn to spring. Multivariate analysis revealed that the abundance of these SRB and PSB correlated to the concentration of H₂S in Lake Uchum. Taken together, this study provides insights into the relationships between changes in bacterial community and environmental features in Lake Uchum.

乌丘姆湖是西伯利亚的一个新近定义的莫克伦湖，其混合固相的季节变化明显。这项研究的特征在于整个四个季节：十月（秋季），三月（冬季），五月（春季）和八月（夏季），该湖的有氧和无氧区细菌群落的时间动态和垂直剖面。缺氧区的细菌丰富度和多样性在各个时间点之间差异很大。整个四个季节中，在整个缺氧和缺氧区域，变形杆菌都是占主导地位的细菌门。变形杆菌（Loktanella）和变形杆菌（Aliidiomarina）分别在缺氧和缺氧区域表现出最高的丰度。此外，整个季节缺氧区的硫酸盐还原菌和硫氧化菌都有连续的变化。最主要的SRB，Desulfonatronovibrio属，是硫化氢（H的主要生产者的一个可能的₂ S），并且典型地积聚最ħ ₂ S IN冬季。乌恰姆湖中典型的产氧养分细菌群是紫色硫细菌（PSB）。夏季，PSB占主导地位（60.76％），而从秋季到春季，相对丰度仅为0.2-1.5％。多变量分析表明，这些SRB和PSB的丰度与H ₂的浓度有关。S在Uchum湖。两者合计，这项研究提供了洞察湖的细菌群落变化与环境特征之间的关系的见解。