Cryoseston in Stara Planina (Balkan) Mountains, Bulgaria

Numerous snow fields persisted in the Stara Planina (Central Balkan) Mountains, some with a very light tint, but with dirty surfaces, at the end of May 2009. The cryoseston community was quite different in individual snow fields. We found Chlorophyta: zygospores of Chloromonas nivalis and Chloromonas rostafinski, Chromophyta: Chromulina elegans, Bacillariophyceae: Aulacoseira granulata var. angustissima, Aulacoseira italica Cyclotella menenghiniana, Navicula nivalis, Hantzschia amphioxys, Fungi: Chionaster nivalis and Selenotila nivalis. Alpine species such as Chlamydomonas nivalis were not found in the snow fields studied, even though they were located in the alpine zone.