Abstract
The abundance of actinomycetes, filamentous fungi and yeasts in the marine epipsammon habitat and their spatial distribution were studied with conventional plating techniques in two marine beaches (Ustka and Czołpino, southern Baltic Sea) which are characterized by different anthropic pressure levels. Actinomycetes constituted the predominant group of studied microorganisms, while the least numerous were yeasts in the sand of both studied beaches. On both of the beaches researched in this study, the amounts of accumulated actinomycetales, fungi and yeasts were similar. When analyzing the distribution of the microflora along the horizontal beach profiles we found significant differences. In the sand collected along the profile perpendicular to the shoreline in Ustka and Czołpino beaches, the highest numbers of actinomycetes, filamentous fungi and yeasts were noted in the samples from the dune and the lowest in those from the subtidal zone and waterline. Generally, higher numbers of studied microorganisms were observed in the surface than in the subsurface sand layer. The occurrence of actinomycetes, filamentous fungi and yeasts showed considerable seasonal variation.