Bacterial community composition of a shallow hypertrophic freshwater lake in China, revealed by 16S rRNA gene sequences

Abstract

The phylogenetic composition of a bacterial community from a hypertrophic freshwater lake in China was investigated by sequencing cloned 16S rRNA genes. Three hundred and thirty-six bacterial clones from four clone libraries in different months (March, May, July and September in 2004) were classified into 142 operational taxonomic units, most of which were affiliated with bacterial divisions commonly found in freshwater ecosystem, e.g. Alpha-, Beta-, Gamma- and Deltaproteobacteria, Bacteriodetes and Actinobacteria. The results showed that the composition of bacterial community in the July library was the most diverse one. Actinobacteria was the most significant lineage in Lake Taihu, with dominant numbers of operational taxonomic units in the May, July and September libraries. Phylogenetic analysis suggested that 53 sequences were grouped into six novel clusters which may represent specific populations indigenous to the environment. Coverage analyses indicated that the clone libraries could provide a fine inventory of bacterial diversity in the lake.

Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

“…Overall, the bacterial community composition could only partially be explained by those factors that defined cyanobacterial species composition. Increased heterogeneity between samples ( Figure 2b) during periods of elevated biomass is consistent with high levels of variability reported among freshwater microbial communities during periods of increasing cyanobacterial biovolume (Wu et al, 2007;.…”

“…To the best of our knowledge, this study represents one of only a few studies to examine the total bacterial population of a freshwater lake on the Australian continent (Dennis et al, 2013) and the first Australian study to do so in the context of a multi-site time series comparable to those conducted elsewhere (Allgaier and Grossart, 2006;Wu et al, 2007; Tang et al, 2010;Dziallas and Grossart, 2011;Eckert et al, 2012;Paver et al, 2013;Wilhelm et al, 2014). During periods of low cyanobacterial biovolume, the microbial community present within the surface water was dominated by the taxa acI (-A and B) (Figure 4a) and alfV-A (Figure 4c).…”

“…Further, such studies have demonstrated that, for cyanobacterial-associated microbial communities, despite the identity of these communities being dependent on the cyanobacterial species present (Bagatini et al, 2014), water chemistry, temperature Xing et al, 2013) and ultimately the freshwater system within which the experiment is based, the function of these communities is largely conserved across local and continental spatial scales (Steffen et al, 2012;Penn et al, 2014;Steffen et al, 2015). Fewer studies have assessed how the nature of the cyanobacterial-associated microbial community changes over temporal scales (Wu et al, 2007;Tang et al, 2010;Xing et al, 2013) with changes in cyanobacterial species dominance and biovolume likely to impact on both the composition and function of these groups.…”

“…Periods of high cyanobacterial biovolume are associated with elevated rates of denitrification (McCarthy et al, 2007) and carbon sequestration (Becker et al, 2011;Sandrini et al, 2014), applying additional perturbations to the water column that in turn contribute to already highly variable systems . Numerous studies have highlighted the diversity of heterotrophic groups that occur within microbial communities associated with freshwater bloomforming cyanobacteria species (Eiler and Bertilsson, 2004;Wu et al, 2007;Berg et al, 2008;Cheng et al, 2011;Dziallas and Grossart, 2011;Grossart et al, 2011;Wilhelm et al, 2011;Steffen et al, 2012;Woodhouse et al, 2012;Cai et al, 2013;Xing et al, 2013;Bagatini et al, 2014). Further, such studies have demonstrated that, for cyanobacterial-associated microbial communities, despite the identity of these communities being dependent on the cyanobacterial species present (Bagatini et al, 2014), water chemistry, temperature Xing et al, 2013) and ultimately the freshwater system within which the experiment is based, the function of these communities is largely conserved across local and continental spatial scales (Steffen et al, 2012;Penn et al, 2014;Steffen et al, 2015).…”

Comparative single-cell genomics reveals potential ecological niches for the freshwater acI Actinobacteria lineage

“…Members of the acI lineage within the phylum Actinobacteria are an intriguing group of free-living ultramicrobacteria that dominate many freshwater ecosystems (Newton et al, 2011), including highnutrient eutrophic (Wu et al, 2007), low-nutrient oligotrophic (Humbert et al, 2009) and dystrophic lakes (Newton et al, 2006). They are also abundant in some marine estuaries (Glockner et al, 2000).…”