Distribution of the verrucomicrobial clade S partobacteria along a salinity gradient in the Baltic Sea.

A recent pyrosequencing study along the whole Baltic Sea salinity transect identified members of the V errucomicrobia class S partobacteria as an important component of Baltic Sea bacterioplankton. In this study, catalysed reporter deposition-fluorescence in situ hybridization was used for cellular quantification. The published probes VER47 and SPA714 were optimized for samples from the Baltic Sea and a new, specific probe ( SPA476) was used to quantify the dominant spartobacterial lineage ' LD29'. The results confirmed that in the brackish surface waters of the Baltic Sea S partobacteria comprise an important component, constituting up to 12% of all bacteria. The positive correlation and physical association of S partobacteria with phytoplankton suggest their involvement in the utilization of phytoplankton-derived organic matter in the Baltic Sea. [ABSTRACT FROM AUTHOR]