Vieira Helena Henriques, Bagatini Inessa Lacativa, de Moraes Guilherme Pavan, Freitas Roberta Mafra, Sarmento Hugo, Bertilsson Stefan, Vieira Armando Augusto Henriques
Hydrobiologický ústav, Biologické cenrum AV ČR, v.v.i, .České Budějovice, Czechia.
Post-graduation Program in Ecology and Natural Resources (PPGERN - CCBS), Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
Front Microbiol. 2022 Aug 18;13:831716. doi: 10.3389/fmicb.2022.831716. eCollection 2022.
The turnover of microbial communities across space is dictated by local and regional factors. Locally, selection shapes community assembly through biological interactions between organisms and the environment, while regional factors influence microbial dispersion patterns. Methods used to disentangle the effects of local and regional factors typically do not aim to identify ecological processes underlying the turnover. In this paper, we identified and quantified these processes for three operational microbial subcommunities (cyanobacteria, particle-attached, and free-living bacteria) from a tropical cascade of freshwater reservoirs with decreasing productivity, over two markedly different dry and rainy seasons. We hypothesized that during the dry season communities would mainly be controlled by selection shaped by the higher environmental heterogeneity that results from low hydrological flow and connectivity between reservoirs. We expected highly similar communities shaped by dispersal and a more homogenized environment during the rainy season, enhanced by increased flow rates. Even if metacommunities were largely controlled by regional events in both periods, the selection had more influence on free-living communities during the dry period, possibly related to elevated dissolved organic carbon concentration, while drift as a purely stochastic factor, had more influence on cyanobacterial communities. Each subcommunity had distinct patterns of turnover along the cascade related to diversity (Cyanobacteria), lifestyle and size (Free-living), and spatial dynamics (particle-attached).
微生物群落的空间周转率受局部和区域因素的支配。在局部层面，选择通过生物体与环境之间的生物相互作用塑造群落组装，而区域因素影响微生物的扩散模式。用于区分局部和区域因素影响的方法通常并非旨在识别周转率背后的生态过程。在本文中，我们针对来自生产力递减的热带淡水水库梯级的三个操作性微生物亚群落（蓝细菌、附着颗粒的细菌和自由生活细菌），在两个明显不同的旱季和雨季期间，识别并量化了这些过程。我们假设在旱季，群落主要受选择控制，这种选择由较低的水文流量和水库之间的连通性导致的较高环境异质性所塑造。我们预计在雨季，由于流速增加，群落会因扩散和更均质的环境而高度相似。即使在两个时期集合群落很大程度上都受区域事件控制，但在旱季选择对自由生活群落的影响更大，这可能与溶解有机碳浓度升高有关，而作为纯粹随机因素的漂移对蓝细菌群落的影响更大。每个亚群落在沿水库梯级的周转率方面都有与多样性（蓝细菌）、生活方式和大小（自由生活细菌）以及空间动态（附着颗粒的细菌）相关的独特模式。
