Cyanobacteria and algae from biofilm at the entrance zone of Petnica Cave

The importance of biofilms in caves, the diversity microorganisms them, their mutual relationship and with substratum are among advancing research topics microbial biospeleology. This is making contribution to knowledge about at cave entrances phototrophic communities them. In that manner, from entrance zone Petnica Cave were examined. Light microscopy showed cyanobacteria exclusively dominant phototrophs (34 taxa out 39 total recorded) coccoid forms prevailing (28 taxa); simple trichal present a lesser extent, while heterocytous ones completely absent. Genera Gloeocapsa, Chroococcus,Gloeothece Leptolyngbya most diverse. Four green algal genera characteristic for aerophytic habitats (Apatococcus, Desmococcus, Haematococcus Trentepohlia) also recorded, Bacillariophytawere observed sporadically. Three groups sampling sites distinguished based on recorded taxa, richness similarity, using non-metric multidimensional scaling (NMDS). Quantitative biofilm characteristics assessed - content chlorophyll (Chl a) was determined, as well contents water, organic inorganic matter. Chl had significant positive correlation matter (r=0.904, P=0.013).