Abstract
Microphytic cenoses that develop on coastal rocks in the area of the water's edge can serve as particularly bright indicator biosystems that clearly display any harmful effects on their habitat. Developing, in fact, in the water-land boundary conditions, in the area of direct impact of the surface film of continuously moving water, they are a kind of " sponges " that collect a variety of agents carried by sea currents from sources of pollution. Accumulating in these communities, such agents are able to change the balance of species in the structure of these coenoses in a short time, as well as cause morphological changes in the species themselves. These modifications of the appearance can be caused both by their phenotypic norm of reaction to the presence and high concentrations of the contaminating agent, and by mutations provoked by one or another agent. Based on the obtained results describing the state of microepiphytic and microepilitic cenoses in various locations located at the end of July 2019 in the vicinity of the port of Ersai and the village of Kuryk, it can be concluded that the communities of all three locations were under stress – however, to a significantly different degree.