EN
The present study examined the impact of solar radiation, including UVB, on the activity of intra- and extracellular bacterial enzymes from the surface microlayer (SM). Following results of the study, it was concluded that solar radiation has a significant impact on the activity of extracellular hydrolases in the SM water. In contrast, no clear changes in activity of these enzymes were observed in subsurface water (SW). The activity of intracellular enzymes (cellular dehydrogenases) of bacteria inhabiting the SM and SW underwent no significant changes in the presence of solar radiation. Furthermore, the study also demonstrated substantial changes in the numbers of bacteria occurring in the SM water depending on the intensity of solar radiation.