Abstract <p>Multispecies cyanobacterial communities (biofilms, the “blooming” phenomenon) may constantly develop and vegetate for a long time on various dense media, including soil and stony substrates. These communities are of interest, both theoretically and practically. Some specific features of such biofilms are due to the fact that, in addition to phototrophs (algae and cyanobacteria), they include heterotrophic bacteria, micromycetes, protozoa and rotifers, i.e., a classical trophic network is observed in such microbial coenoses, which makes it possible for such consortia to exist for a long time, primarily because cyanobacteria have an autotrophic mode of nutrition with respect to carbon (photosynthesis) and nitrogen (nitrogen fixation), which ensures their stability not only under stable environmental conditions, but also in stressful situations. From a practical viewpoint, cyanobacterial biofilms can be used in biotechnology, in the fields such as biosorption and the synthesis of various exometabolites. In addition, they could be useful in the context of exploitation of various construction objects made of materials similar to that used as a substrate for the growth of these microorganisms in our experiment. The studied biofilms were maintained for 15 years in a model experiment on a stony substrate. Our analyses carried out to determine the qualitative and quantitative composition of the phototrophic component of these biofilms, their antifusarium activity, the content of pigments and the concentration of heavy metals showed that the growths were characterized not only by morphological differences, but also by significant differences in the determined indicators depending on growth pattern. Within this stony substrate, three different types of biofilms and specific outgrowths on the walls of the container, where cultivation took place, were identified.</p>