Generic composition and metabolic activity of bacteria inhabiting surface seawater layers

Generic composition and metabolic activity of neustonic and planktonic bacteria inhabiting seawater in the region of the Gdansk Deep were determined. In each of the studied water layers, bacteria of the Flavobacterium-Cytophaga group domi-nated, while bacteria of the Micrococcus, Acineto-bacter, Bacillus genera and of the Arthrobacter-Corynebacterium group constituted only a slight percentage of the bacterioneuston and bakterioplankton. Different levels of metabolic activity of bacteria inhabiting different water layers were measured. The intensity of oxidization of respiratory substrates depended also on taxonomic position of bacteria. Generally casein hydrolyzate was the most actively metabolized respiratory substrate; sodium acetate was oxidized with lesser intensity. A considerable impact of salinity on the level of metabolic activity was noticed.