Ren Ze, Zhang Cheng, Li Xia, Ma Kang, Zhang Zhe, Feng Kexin, Cui Baoshan
Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, China.
School of Environment, Beijing Normal University, Beijing, China.
Front Microbiol. 2021 Oct 22;12:716732. doi: 10.3389/fmicb.2021.716732. eCollection 2021.
Thermokarst lakes are a ubiquitous and important landscape feature in cold regions and are changing tremendously due to the accelerated climate change. In thermokarst lakes, sediment and water are two distinct but highly interconnected habitats, harboring different bacterial communities in terms of taxonomic composition. However, the co-occurrence networks of these bacterial communities remain unclear. Here, we investigate the co-occurrence ecological networks of sediment and water bacterial communities for thermokarst lakes in the Yellow River Source Area on the Qinghai-Tibet Plateau. The results show that the bacterial communities construct distinct co-occurrence networks in sediment and water. The metacommunity network was parsed into four major modules formed by the operational taxonomic units (OTUs) enriched in sediment or water independently, and water-enriched OTUs exhibited much closer interconnections than sediment-enriched OTUs. When considering the sediment and water bacterial networks separately, different topological properties and modular patterns present: the sediment bacterial network was more clustered while the modules less responded to the environmental variables. On the contrary, the water bacterial network was more complex with the OTUs more interconnected and its modules more responded to the environmental variables. Moreover, the results of the structural equation model suggest that, by the influence of environmental variations on individual modules, the water bacterial communities would be more vulnerable under the fact of accelerating climate change. This study provides insights beyond a conventional taxonomic perspective, adding our knowledge of the potential mechanisms structuring bacterial community assembly and improving our prediction of the responses of this fast-changing ecosystem to future climate change.
热喀斯特湖是寒冷地区普遍且重要的地貌特征，由于气候变化加速，其正在发生巨大变化。在热喀斯特湖中，沉积物和水是两个截然不同但又高度相互关联的栖息地，在分类组成方面蕴藏着不同的细菌群落。然而，这些细菌群落的共生网络仍不清楚。在此，我们研究了青藏高原黄河源区热喀斯特湖沉积物和水细菌群落的共生生态网络。结果表明，细菌群落在沉积物和水中构建了不同的共生网络。元群落网络被解析为由独立富集于沉积物或水中的操作分类单元（OTU）形成的四个主要模块，且富集于水中的OTU表现出比富集于沉积物中的OTU更为紧密的相互连接。当分别考虑沉积物和水细菌网络时，呈现出不同的拓扑性质和模块模式：沉积物细菌网络聚类性更强，而模块对环境变量的响应较小。相反，水细菌网络更为复杂，OTU之间的相互连接更多，其模块对环境变量的响应更大。此外，结构方程模型的结果表明，在环境变化对各个模块的影响下，在气候变化加速的情况下，水细菌群落将更加脆弱。本研究提供了超越传统分类学视角的见解，增加了我们对构建细菌群落组装潜在机制的认识，并改进了我们对这个快速变化的生态系统对未来气候变化响应的预测。
