Bacterial Community Composition in Central European Running Waters Examined by Temperature Gradient Gel Electrophoresis and Sequence Analysis of 16S rRNA Genes

Abstract

The bacterial community composition in small streams and a river in central Germany was examined by temperature gradient gel electrophoresis (TGGE) with PCR products of 16S rRNA gene fragments and sequence analysis. Complex TGGE band patterns suggested high levels of diversity of bacterial species in all habitats of these environments. Cluster analyses demonstrated distinct differences among the communities in stream and spring water, sandy sediments, biofilms on stones, degrading leaves, and soil. The differences between stream water and sediment were more significant than those between sites within the same habitat along the stretch from the stream source to the mouth. TGGE data from an entire stream course suggest that, in the upper reach of the stream, a special suspended bacterial community is already established and changes only slightly downstream. The bacterial communities in water and sediment in an acidic headwater with a pH below 5 were highly similar to each other but deviated distinctly from the communities at the other sites. As ascertained by nucleotide sequence analysis, stream water communities were dominated by Betaproteobacteria (one-third of the total bacteria), whereas sediment communities were composed mainly of Betaproteobacteria and members of the Fibrobacteres/Acidobacteria group (each accounting for about 25% of bacteria). Sequences obtained from bacteria from water samples indicated the presence of typical cosmopolitan freshwater organisms. TGGE bands shared between stream and soil samples, as well as sequences found in bacteria from stream samples that were related to those of soil bacteria, demonstrated the occurrence of some species in both stream and soil habitats. Changes in bacterial community composition were correlated with geographic distance along a stream, but in comparisons of different streams and rivers, community composition was correlated only with environmental conditions.

Seasonal and Spatial Changes of Planktonic Bacterial Communities Inhabiting the Natural Thermal Lake Hévíz, Hungary

“…Other microbial investigations on aquatic environments also confi rmed that bacterial communities associated with surfaces clearly differed from free-living communities [30,31]. Due to decomposition processes taking place in freshwater sediments, their carbon content and the available electron acceptors may generally differ from those of the overlaying water layers which may contribute to the development of distinct microbial communities [32].…”

The impact of physico-chemical water quality parameters on bacterial diversity in the Vaal River, South Africa

“…Alphaproteobacteria, Betaproteobacteria, Gamma proteobacteria and Actinobacteria are ubiquitous groups in freshwater habitats (Gich et al, 2005;Anderson-Glenna et al, 2008) and are numerically important in river systems (Beier et al, 2008;Lemke et al, 2009). Members of Betaproteobacteria respond rapidly to organic and inorganic nutrient enrichment (Hahn, 2003;Simek et al, 2005) and have been isolated from various polluted and unpolluted freshwater bodies (De Figueiredo et al, 2011;Haller et al, 2011).…”

An Opinion on Spring Habitats within the Earth’s Critical Zone in Headwater Regions

“…Spring microhabitat types can be separated in mineral-organic complexes and on a particle and mineral scale as a nanoscale entity. The microscopic scale is relevant for research questions regarding individual micro-organisms or microbiological communities, such as biofilm and their relation to substrate, to study and understand substratespecific microbial consortia and their colonization of substratum [95,96]. The latter is important in understanding the rates of nutrient uptake (e.g., within the nitrogen cycle on the river continuum), storage, regeneration, and export in headwater regions [16].…”