Data from: Short term dynamics of diversity patterns: evidence of continual reassembly within lacustrine small eukaryotes

The short-term variation in the community structure of freshwater small eukaryotes (0.2-5 μm) was investigated in a mesotrophic lake every 2-3 days over one summer by coupling three molecular methods: 454 amplicon pyrosequencing, qPCR and TSA-FISH. The pyrosequencing approach unveiled a much more extensive small-eukaryotic diversity (991 OTUs) than has been described previously. The vast majority of the diversity described was represented by rare OTUs (≤ 0.01% of reads) belonging primarily to Cryptomycota, Dikarya and photosynthetic organisms, which were never detected as abundant in any of the samples. The small eukaryote community was characterized by a continual and important reassembly. These rearrangements involved the 20 “core taxa” (≥ 1% of reads), and, were essentially due to a handful of OTUs that were detected in intermediate abundance (0.01-1% of reads) and sporadically in dominant taxa. Putative bacterivorous (Ciliophora and Cercozoa) as well as parasitic and saprotrophic taxa (Perkinsozoa and Cryptomycota) were involved in these changes of diversity. A putative infection of microalgae by a lacustrine perkinsozoan was also reported for the first time in this study. Open questions regarding both the patterns that govern the rapid small eukaryote reassemblies and the possible biogeography of these organisms arise from this study.

本研究于某夏季期间，每隔2-3天对一座中营养型湖泊中的淡水小型真核生物（0.2-5μm）群落结构的短期动态变化展开调查，整合了三种分子检测手段：454扩增子焦磷酸测序（454 amplicon pyrosequencing）、实时定量PCR（qPCR）以及TSA-FISH。该测序策略揭示了远超既往报道的小型真核生物多样性，共获得991个操作分类单元（OTU）。绝大多数已探明的多样性由稀有操作分类单元构成，这类单元的读段（reads）占比≤0.01%，且主要隶属于隐真菌门（Cryptomycota）、双核真菌类群（Dikarya）以及光合生物，在所有样本中均未以优势类群的形式被检出。该小型真核生物群落呈现出持续且显著的群落重构特征。此类重构涉及20个"核心类群"（读段占比≥1%），其驱动因素主要为少数丰度处于中间水平（读段占比0.01%-1%）、偶尔成为优势类群的操作分类单元。参与此类多样性动态变化的类群包括推测的食细菌性类群：纤毛虫门（Ciliophora）、丝足虫门（Cercozoa），以及寄生和腐生类群：帕金虫门（Perkinsozoa）、隐真菌门。本研究还首次报道了一种湖生帕金虫门类群对微藻的潜在感染现象。本研究提出了两项待解的科学问题：一是调控小型真核生物快速群落重构的潜在模式机制，二是此类生物可能存在的生物地理学分布特征。