RÉSUMÉ

Communities of macro- and microperiphyton and their annual succession on concrete slabs of different exposure terms were studied in the experimental installation. The preponderance of green algae and diatoms, having the quickest reproduction rate, was discovered. The quantitative indicators of plant communities were similar to those of natural populations. The seasonal specificity of micro-and macrobiofouling was described, and the most active periods of colonization were determined. The stabilization of microalgal communities was revealed in the second half of the year; the species diversity and concomitant species development indicators increased, whereas the abundance of dominant species diminished. It is shown that the marginal effect of biofouling by microalgae is expressed in more intensive colonization of edges and marginal areas.