State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Environ Res. 2022 Sep;212(Pt D):113376. doi: 10.1016/j.envres.2022.113376. Epub 2022 May 10.
Microbes (e.g., bacteria and archaea) are indispensable components for the key biological processes of estuarine ecosystems and three main habitats (sediment, particle, and water) are harboring diverse estuarine microbes. However, we still know little about how the microbial community structures, potential keystone species, and network properties change among these three habitats in estuarine ecosystems. In this study, we collected size-fractioned water and sediment samples from the Pearl River Estuary to reveal their microbial diversity, community structures, network properties, and potential keystone taxa. We found that the sediment microbial community was remarkably more diverse than particle-attached (PA) and free-living (FL) communities, whereas its ecological network was less complex in terms of node distance and connectivity. TOC was determined as the main driver of sediment community, while the PA and FL communities were predominantly shaped by NO, non-ionic ammonia (NH) and pH. Among the bulk water, there were no significant differences between PA and FL communities in diversity, community structure, and network complexity. However, the PA community was more susceptible to metal elements, suggesting their higher level of involvement in physiological metabolism. Potential keystone taxa among community networks were taxonomically divergent in three habitats. Specifically, Synechococcales (Cyanobacteria) and Actinomarinales (Actinobacteria) exclusively served as the module-hubs in FL network, while members from phylum Proteobacteria and Bacteroidetes were the module-hubs and connectors in PA network. Potential keystone taxa in sediment network were more diverse and covered 9 phyla, including the only archaeal lineage Bathyarchaeia (Crenarchaeota). Overall, our study provided more detailed information about estuarine microbial communities in three habitats, especially the potential keystone species, which provided new perspectives on evaluating further effects of anthropogenic disturbances on estuarine microbes and facilitated the environment monitoring based on microbial community.
微生物（例如细菌和古菌）是河口生态系统关键生物过程不可或缺的组成部分，而三个主要栖息地（沉积物、颗粒和水）则蕴藏着多样的河口微生物。然而，我们仍然不太了解微生物群落结构、潜在的关键物种以及网络特性在河口生态系统这三个栖息地之间是如何变化的。在这项研究中，我们从珠江口采集了不同大小的水和沉积物样本，以揭示它们的微生物多样性、群落结构、网络特性和潜在的关键分类群。我们发现，沉积物微生物群落的多样性明显高于颗粒附着（PA）和自由生活（FL）群落，而其生态网络在节点距离和连通性方面则不太复杂。TOC 被确定为沉积物群落的主要驱动因素，而 PA 和 FL 群落主要受 NO、非离子氨（NH）和 pH 的影响。在总水中，PA 和 FL 群落的多样性、群落结构和网络复杂性之间没有显著差异。然而，PA 群落对金属元素更为敏感，表明它们在生理代谢中参与度更高。群落网络中的潜在关键类群在三个栖息地中具有不同的分类学特征。具体来说，蓝细菌（蓝细菌）和放线菌（放线菌）仅作为 FL 网络的模块枢纽，而厚壁菌门和拟杆菌门的成员则是 PA 网络的模块枢纽和连接器。沉积物网络中的潜在关键类群更加多样化，涵盖了 9 个门，包括唯一的古菌谱系 Bathyarchaeia（古菌）。总的来说，我们的研究提供了更多关于三个栖息地中河口微生物群落的详细信息，特别是潜在的关键物种，这为评估人为干扰对河口微生物的进一步影响提供了新的视角，并有助于基于微生物群落进行环境监测。
