Abundance and phylogenetic diversity of bacterioneuston and bacterioplankton inhabiting marine harbor channel on the southern coast of the Baltic Sea

The abundance of bacterioneuston and bacterioplankton and their taxonomic composition were determined with the fluorescence in situ hybridization (FISH) method in the harbor channel in Ustka. Among bacteria inhabiting the surface microlayer and subsurface water two phylogenetic groups dominated: Gammaproteobacteria and Cytophaga-Flavobacterium. The abundance of bacterial taxonomic groups in the water of the studied channel showed typical ranking, i.e., Gammaproteobacteria > Cytophaga-Flavobacterium > Marine alpha cluster > Pseudomonas > Vibrio. Total prokaryotic cell differed along the vertical and horizontal profiles. Similar taxonomic composition of bacterioneuston and bacterioplankton in both studied profiles were noted. All studied taxonomic groups occurred more often in the surface microlayer than subsurface water.