The paper presents results of screening of microscopic fungi occurring in groundwater, soil and air in selected localities of the small Danube island during the period of 1994-1995. Totally, 33 genera of micromycetes were isolated. From that number 10 genera occurred in all components of biosphere. A 100% occurrence in all samples was recorded only in the genus Cladosporium. The representants of other micromycetic genera were identified only in some localities and biotopes. Knowling this problem requires a long-term special interests to be paid to mycetic revitalization of all biosphere components and their mutual relationships, because this short-term observation could not have solved the problem.