Data from: Spatial and successional dynamics of microbial biofilm communities in a grassland stream ecosystem

Biofilms represent a metabolically active and structurally complex component of freshwater ecosystems. Ephemeral prairie streams are hydrologically harsh and prone to frequent perturbation. Elucidating both functional and structural community changes over time within prairie streams provides a general understanding of microbial responses to environmental disturbance. We examined microbial succession of biofilm communities at three sites in a third-order stream at Konza Prairie over a 2 – 64 day period. Microbial abundance (bacterial abundance, chlorophyll a concentrations) increased and never plateaued during the experiment. Net primary productivity (net balance of oxygen consumption and production) of the developing biofilms did not differ statistically from zero until 64 days suggesting a balance of the use of autochthonous and allochthonous energy sources until late succession. Bacterial communities (MiSeq analyses of the V4 region of 16S rRNA) established quickly. Bacterial richness, diversity, and evenness were high after 2 days and increased over time. Several dominant bacterial phyla (Beta-, Alphaproteobacteria, Bacteroidetes, Gemmatimonadetes, Acidobacteria, Chloroflexi) and genera (Luteolibacter, Flavobacterium, Gemmatimonas, Hydrogenophaga) differed in relative abundance over space and time. Bacterial community composition differed across both space and successional time. Pairwise comparisons of phylogenetic turnover in bacterial community composition indicated that early stage succession ( 16d) was driven by stochastic processes, whereas later stages were driven by deterministic selection regardless of site. Our data suggest that microbial biofilms predictably develop both functionally and structurally indicating distinct successional trajectories of bacterial communities in this ecosystem.生物膜（Biofilms）是淡水生态系统中代谢活跃且结构复杂的组成部分。短命草原溪流（Ephemeral prairie streams）水文条件严苛，且易遭受频繁扰动。阐明草原溪流中微生物群落的结构与功能随时间的变化规律，可帮助我们从整体上理解微生物对环境扰动的响应机制。本研究于康扎草原（Konza Prairie）的一条三级溪流（third-order stream）的三个采样点位开展实验，在2至64天的周期内监测了生物膜群落的微生物演替过程。 实验期间，微生物丰度（包括细菌丰度与叶绿素a（chlorophyll a）浓度）持续上升且未达到平台期。发育中生物膜的净初级生产力（Net primary productivity，即氧气消耗与产生的净平衡）在第64天前均无统计学意义上的显著差异，表明在演替后期之前，微生物对本土能源（autochthonous energy sources）与外源能源（allochthonous energy sources）的利用处于动态平衡。 细菌群落通过针对16S rRNA的V4区域开展的MiSeq测序分析（MiSeq analyses）得以解析，其定植过程十分迅速：实验第2天时，细菌丰富度、多样性与均匀度已处于较高水平，并随时间推移进一步提升。多个优势细菌类群——包括β-、α-变形菌纲（Beta-, Alphaproteobacteria）、拟杆菌门（Bacteroidetes）、芽单胞菌门（Gemmatimonadetes）、酸杆菌门（Acidobacteria）、绿弯菌门（Chloroflexi），以及Luteolibacter属、黄杆菌属（Flavobacterium）、芽单胞菌属（Gemmatimonas）、噬氢菌属（Hydrogenophaga）等——的相对丰度随空间与时间发生显著变化。细菌群落组成同时存在空间与演替时间维度上的差异。 针对细菌群落组成的系统发育周转（phylogenetic turnover）进行两两比较后发现：演替早期（<16天）由随机过程（stochastic processes）驱动，而演替后期则不受采样位点影响，由确定性选择（deterministic selection）主导。本研究数据表明，微生物生物膜在功能与结构上均呈现可预测的发育过程，这意味着该生态系统中细菌群落存在独特的演替轨迹（successional trajectories）。