Greenland ice sheet covers the majority of Greenland's surface. Despite low temperatures, various microbial communities are adapted to such environment and can therefore be found on the island. Studies conducted up to date mostly emphasize unculturable ice algae from the Zygnematophyceae class and bacteria. However fungi, have not been studied yet. The European project »Black and Bloom« is dealing with darkening of the Greenland ice sheet (black ice phenomenon) and its consequences. In the scope of the project five different habitats were sampled from which 260 fungal and 46 bacterial strains were isolated. Isolates were identified to the genus level, and in some cases to species level based on selected nucleotide sequences. More specifically we studied isolates of the genera Articulospora and Psychrophila (Helotiales, Ascomycota). They were identified based on nucleotide sequences of the ITS rDNA and specific housekeeping genes. Apart from that, we examined morphological characteristics of the selected isolates and determined their enzymatic activities and the capacity to grow at different temperatures and different salt concentrations. Based on the results, we predict that the examined isolates of the Articulospora and Psychrophila genera represent new species. In the last part of the thesis, we have examined the interaction between the chosen isolate of genus Articulospora with unculturable ice algae Ancylonema nordenskiöldii and Mesotaenium berggrenii. The latter two species cause ice darkening on Greenland due to heavy blooming and black pigment production. We come to a conclusion, the chosen fungi is in interaction with unculturable ice algae that reminiscence to lichen.