Xin Guo, Xiaohong Shi, Yujiao Shi, Wenbao Li, Yanjun Wang, Zhimou Cui, Arvolab Lauri
Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China.
Inner Mongolia Key Laboratory of Protection and Utilization of Water Resources, Hohhot, China.
Front Microbiol. 2024 Aug 21;15:1448919. doi: 10.3389/fmicb.2024.1448919. eCollection 2024.
Microorganisms in lakes are sensitive to salinity fluctuations. Despite extensive prior research on bacterial communities, our understanding of their characteristics and assembly mechanisms in lakes, especially in desert lakes with different salinities. To address this issue, we collected three samples from freshwater lakes, six from brackish lakes, and five from salt lakes in the Badanjilin Desert. The 16S rRNA gene sequencing was applied to investigate the bacterial interactions with rising salinity, community coexistence patterns, and assembly mechanisms. Our findings suggested that the increased lake salinity significantly reduces the bacterial community diversity and enhanced the community differentiation. Significant variations were observed in the contribution of biomarkers from Cyanobacteria, Chloroflexi, and Halobacterota to the composition of the lake bacterial communities. The bacterial communities in the salt lakes exhibited a higher susceptibility to salinity limitations than those in the freshwater and brackish lakes. In addition, the null modeling analyses confirmed the quantitative biases in the stochastic assembly processes of bacterial communities across freshwater, brackish, and saline lakes. With the increasing lake salinity, the significance of undominated and diffusion limitation decreased slightly, and the influence of homogenizing dispersal on community assembly increased. However, the stochasticity remained the dominant process across all lakes in the Badanjilin Desert. The analysis of co-occurring networks revealed that the rising salinity reduced the complexity of bacterial network structures and altered the interspecific interactions, resulting in the increased interspecies collaboration with increasing salinity levels. Under the influence of salinity stress, the key taxon Cyanobacteria in freshwater lakes () was replaced by Proteobacteria ( and ) in brackish lakes, and Thermotogota () in salt lakes. The results indicated the symbiotic patterns of bacterial communities across varying salinity gradients in lakes and offer insights into potential mechanisms of community aggregation, thereby enhancing our understanding of bacterial distribution in response to salinity changes.
湖泊中的微生物对盐度波动很敏感。尽管之前对细菌群落进行了广泛研究，但我们对其在湖泊中的特征和组装机制，尤其是在不同盐度的沙漠湖泊中的了解仍很有限。为了解决这个问题，我们从巴丹吉林沙漠的淡水湖采集了3个样本，从咸水湖采集了6个样本，从盐湖采集了5个样本。应用16S rRNA基因测序来研究细菌与盐度上升的相互作用、群落共存模式和组装机制。我们的研究结果表明，湖泊盐度的增加显著降低了细菌群落多样性并增强了群落分化。在蓝细菌、绿弯菌门和盐杆菌门的生物标志物对湖泊细菌群落组成的贡献方面观察到显著差异。盐湖中的细菌群落比淡水湖和咸水湖中的细菌群落对盐度限制更敏感。此外，空模型分析证实了淡水湖、咸水湖和盐湖中细菌群落随机组装过程中的定量偏差。随着湖泊盐度的增加，未占主导地位和扩散限制的重要性略有下降，而同质化扩散对群落组装的影响增加。然而，随机性仍然是巴丹吉林沙漠所有湖泊中的主导过程。共现网络分析表明，盐度上升降低了细菌网络结构的复杂性并改变了种间相互作用，导致随着盐度水平的增加种间协作增加。在盐度胁迫的影响下，淡水湖中的关键分类群蓝细菌（ ）被咸水湖中的变形菌门（ 和 ）以及盐湖中的栖热袍菌门（ ）所取代。结果表明了湖泊中不同盐度梯度下细菌群落的共生模式，并为群落聚集的潜在机制提供了见解，从而增强了我们对细菌响应盐度变化分布的理解。
