Diversity and seasonal variability of bacterial community structure in the river Aliakmon, Greece: Analysis by the molecular technique fish

Abstract

AbstractAimFluorescence in situ hybridization (FISH) with rRNA‐targeted oligonucleotide probes was used to investigate the phylogenetic composition of bacterial community in samples from the river Aliakmon, the longest river in Greece. Diversity of bacterial community in different habitats of the same river, as well as seasonal variation, was also examined.Methods and ResultsOligonucleotide probes specific for the domain Bacteria and five bacterial groups (high GC content, low GC content, Alpha‐, Beta‐ and Gammaproteobacteria) were used. The Gram‐positive populations were dominated by Firmicutes (low GC content), while Gammaproteobacteria showed increased abundances compared to Betaproteobacteria, although an enrichment step for samples was used, something which might had favoured the gamma subclass. Seasonal and along river variations were observed for Gram‐negative bacteria but not for Firmicutes.ConclusionsWe conclude that the changes in bacterial community composition was correlated with environmental conditions and resulted from interactions brought about by physical and biological factors. To our knowledge, this is the first study describing structure and diversity of a bacterial community in a Greek freshwater system, with the use of FISH. Copyright © 2009 John Wiley & Sons, Ltd.