Li Saifei, Liu Yang, Wang Wenqiang, Liu Yongqin, Ji Mukan
College of Ecology, Lanzhou University, Lanzhou 730000, China.
Center for Pan-Third Pole Environment, Lanzhou University, Lanzhou 730000, China.
FEMS Microbiol Ecol. 2025 Jan 28;101(2). doi: 10.1093/femsec/fiaf001.
In polar and alpine regions, global warming and landform changes are draining lakes, transforming them into permafrost with altered microbial communities and element cycling. In this study, we investigated bacterial and archaeal (prokaryotic) community changes in the newly exposed sediment of Zonag Lake (Tibetan Plateau), focusing on prokaryotic diversity, community structure, and genes involved in carbon fixation and nitrogen cycling across lateral (up to 800 m) and vertical (up to 80 cm) horizons. The results showed that prokaryotic richness decreased across the lateral horizons, coinciding with reductions in carbon concentrations. Dramatic changes in community structure were also observed, primarily influenced by the distance from the lake and then by sediment depth, with environmental filtering and dispersal limitations shaping the lateral and vertical distributions, respectively. Based on PICRUSt2 results, the relative abundance of genes related to carbon fixation increased along the lateral horizon, suggesting that microbial carbon fixers are counteracting the carbon loss during permafrost formation. In contrast, the genes related to denitrification also increased, which may lead to nitrogen loss and contribute to global warming by releasing nitric oxide gas. This study highlights the resilience of prokaryotic communities in drained lake basins and their ecological implications under global warming.
在极地和高山地区，全球变暖和地形变化正在排干湖泊，将它们转变为永久冻土，微生物群落和元素循环也随之改变。在本研究中，我们调查了若拉错湖（青藏高原）新暴露沉积物中的细菌和古菌（原核生物）群落变化，重点关注原核生物多样性、群落结构以及横向（长达800米）和纵向（长达80厘米）范围内参与碳固定和氮循环的基因。结果表明，原核生物丰富度在横向范围内降低，这与碳浓度的降低相一致。还观察到群落结构发生了显著变化，主要受距湖距离的影响，其次受沉积物深度的影响，环境过滤和扩散限制分别塑造了横向和纵向分布。基于PICRUSt2结果，与碳固定相关的基因相对丰度沿横向范围增加，这表明微生物碳固定者正在抵消永久冻土形成过程中的碳损失。相反，与反硝化作用相关的基因也增加了，这可能导致氮损失，并通过释放一氧化氮气体加剧全球变暖。本研究强调了排水湖盆中原核生物群落的恢复力及其在全球变暖下的生态影响。
