Coherent dynamics and association networks among lake bacterioplankton taxa

Abstract

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.

Bacterial assembly and temporal dynamics in activated sludge of a full-scale municipal wastewater treatment plant

“…Monthly, seasonal and inter-annual variability of bacterial structure The seasonal succession of bacterial communities over various environmental gradients has been widely observed in many natural ecosystems, including soil (Lipson and Schmidt, 2004), oceans (Gilbert et al, 2011), lakes (Eiler et al, 2011;Paver et al, 2013). However, in an artificially controlled, half-close engineered biological wastewater treatment system, such as activated sludge, whether the dynamics of the bacterial community structure still follow a seasonal succession remains to be explored.…”

Bacterioplankton niche partitioning in the use of phytoplankton-derived dissolved organic carbon: quantity is more important than quality

“…Various studies have used the network approach to illustrate the interactions among microbes, yet the interactions are usually defined by co-existence in a water sample or by co-variation throughout time series (for example, Barberan et al, 2011;Eiler et al, 2011;Steele et al, 2011;Lima-Mendez et al, 2015), yet rarely by a real quantification of the interaction strengths (ISs) in terms of carbon flow, for example. We previously developed a metric that captures the mutualistic interaction of several bacterioplankton phylogenetic groups and different phytoplankton species mediated by DOCp, applying an adapted version of the MAR-FISH (microautoradiography combined with fluorescent in situ hybridization) technique with radiolabeled exudates from axenic algal cultures (Sarmento and Gasol, 2012).…”

Vertical Distribution of Functional Potential and Active Microbial Communities in Meromictic Lake Kivu

“…Meromictic lakes are good model systems for microbial ecology research due to the high vertical stability of the water masses and physicochemical gradients (in particular oxygen) that lead to relatively constant stratification of microbial populations [1][2][3]. Since microbes are key players in biogeochemical cycles, investigations on microbial diversity and community composition are important to understand the ecological functioning of lakes.…”