Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden.
ISME J. 2012 Feb;6(2):330-42. doi: 10.1038/ismej.2011.113. Epub 2011 Sep 1.
Bacteria have important roles in freshwater food webs and in the cycling of elements in the ecosystem. Yet specific ecological features of individual phylogenetic groups and interactions among these are largely unknown. We used 454 pyrosequencing of 16S rRNA genes to study associations of different bacterioplankton groups to environmental characteristics and their co-occurrence patterns over an annual cycle in a dimictic lake. Clear seasonal succession of the bacterioplankton community was observed. After binning of sequences into previously described and highly resolved phylogenetic groups (tribes), their temporal dynamics revealed extensive synchrony and associations with seasonal events such as ice coverage, ice-off, mixing and phytoplankton blooms. Coupling between closely and distantly related tribes was resolved by time-dependent rank correlations, suggesting ecological coherence that was often dependent on taxonomic relatedness. Association networks with the abundant freshwater Actinobacteria and Proteobacteria in focus revealed complex interdependencies within bacterioplankton communities and contrasting linkages to environmental conditions. Accordingly, unique ecological features can be inferred for each tribe and reveal the natural history of abundant cultured and uncultured freshwater bacteria.
细菌在淡水食物网和生态系统元素循环中起着重要作用。然而，个体系统发育群的特定生态特征以及这些群之间的相互作用在很大程度上是未知的。我们使用 454 焦磷酸测序 16S rRNA 基因来研究不同浮游细菌群与环境特征的关联及其在一年周期内的共生模式在一个二态湖中。观察到浮游细菌群落的明显季节性演替。在将序列分类为先前描述的和高度解析的系统发育群（部落）之后，它们的时间动态揭示了与季节性事件的广泛同步性和关联，例如冰覆盖、冰融、混合和浮游植物大量繁殖。通过时间相关的等级相关性来解析密切和远距离相关的部落之间的耦合，这表明生态一致性通常取决于分类学上的相关性。以丰富的淡水放线菌和变形菌为重点的关联网络揭示了浮游细菌群落内的复杂相互依存关系以及与环境条件的对比联系。因此，可以推断每个部落都具有独特的生态特征，并揭示了丰富的培养和未培养淡水细菌的自然历史。
