EN
This paper presents results of research concerning bacteria inhabiting the surface microlayer and subsurface waters of the eutrophic lake Jeziorak Maly. Total number, biomass and share of heterotrophic bacteria was higher in the surface microlayer than in subsurface water. The rate of secondary production of bacteria was higher in the subsurface water. There is a considerably higher percentage of neustonic bacteria showing the ability to degrade different compounds than planktonie ones.