Laboratory of Microbial Processes and Biodiversity, Departamento de Hidrobiologia, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
Programa de Pós-graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
PLoS One. 2019 Aug 9;14(8):e0220695. doi: 10.1371/journal.pone.0220695. eCollection 2019.
Amazonian floodplains form complex hydrological networks that play relevant roles in global biogeochemical cycles, and bacterial degradation of the organic matter in these systems is key for regional carbon budget. The Amazon undergoes extreme seasonal variations in water level, which produces changes in landscape and diversifies sources of organic inputs into floodplain systems. Although these changes should affect bacterioplankton community composition (BCC), little is known about which factors drive spatial and temporal patterns of bacterioplankton in these Amazonian floodplains. We used high-throughput sequencing (Illumina MiSeq) of the V3-V4 region of the 16S rRNA gene to investigate spatial and temporal patterns of BCC of two size fractions, and their correlation with environmental variables in an Amazon floodplain lake (Lago Grande do Curuai). We found a high degree of novelty in bacterioplankton, as more than half of operational taxonomic units (OTUs) could not be classified at genus level. Spatial habitat heterogeneity and the flood pulse were the main factors shaping free-living (FL) BCC. The gradient of organic matter from transition zone-lake-Amazon River was the main driver for particle-attached (PA) BCC. The BCC reflected the complexity of the system, with more variation in space than in time, although both factors were important drivers of the BCC in this Amazon floodplain system.
亚马逊河泛滥平原形成了复杂的水文网络，在全球生物地球化学循环中发挥着重要作用，而这些系统中有机物的细菌降解对区域碳预算至关重要。亚马逊河经历着极端的水位季节性变化，这导致了景观的变化，并使进入泛滥平原系统的有机物质输入源多样化。尽管这些变化应该会影响细菌浮游生物群落组成（BCC），但对于哪些因素驱动这些亚马逊河泛滥平原的细菌浮游生物的时空格局，我们知之甚少。我们使用 Illumina MiSeq 高通量测序（V3-V4 区 16S rRNA 基因），调查了两个大小分数的 BCC 的时空格局，以及它们与亚马逊泛滥湖（Lago Grande do Curuai）环境变量的相关性。我们发现了细菌浮游生物的高度新颖性，超过一半的操作分类单元（OTUs）无法在属级分类。自由生活（FL）BCC 的主要形成因素是空间栖息地异质性和洪水脉冲。从过渡带-湖-亚马逊河的有机物梯度是颗粒附着（PA）BCC 的主要驱动因素。BCC 反映了系统的复杂性，空间变化比时间变化更大，尽管这两个因素都是这个亚马逊河泛滥平原系统中 BCC 的重要驱动因素。
