Phototrophic bacterioplankton of four stratified boreal ferruginous lakes of the Northern Hemisphere: comparative analysis of vertical 16S rRNA profiles

Abstract

The aim of the study was to analyze the phototrophic bacterioplankton composition and vertical structure of Lake Linevo, a polyhumic iron-rich lake in the Raifa section of the Volga-Kama Nature Reserve (Tatarstan, Russia), and three other ferruginous boreal lakes in Russia, Finland, and Canada. The results demonstrated the presence of identical phylogenetic groups and dominant operational taxonomic units, but the inntensity of development and overall structure of the phototrophic bacterioplankton community was nevertheless different. Highest abindance was detected in Lake Linevo which had a number of unique features when compared to the other studied lakes. In particular, it had the largest number of phototrophic bacteria and a significant abundance and diversity of phototrophic Chloroflexales that were scarce in the other lakes. It seems desirable to further characterize the oxygen-depleted zone of this lake in more detail and, if possibly, to apply metagenomic and whole-genome analysis methods that have already been used in lakes Lovojärvi and L227 as well as many other boreal brown-water lakes.