Mycelial fungi from cryopegs (tundra, Kolyma lowland, Russia) have been studied. The use of media with different amounts of salt and cultivation at 4 and 25 °C allowed us to isolate filamentous fungi assigned to 11 species. The micromycetes of genus Geomyces were found most often. The total amount of fungi reached 1–4×102 CFU ml−1 of water. The extreme conditions of the cryopegs – the high salinity of the water (150–200 g l−1) and the constant low temperatures (average annual temperature is from −9 to −11 °C) – might serve as a model for the conditions of interplanetary environments.

In the Arctic there are lenses of overcooled water brines (cryopegs) sandwiched within permafrost marine sediments 100–120 thousand years old. We have investigated the physiological properties of the pure cultures of anaerobic Clostridium sp. strain 14D1 and two strains of aerobic bacteria Psychrobacter sp. isolated from these cryopegs. The structural and physiological characteristics of new bacteria from water brines have shown their ability to survive and develop under harsh conditions, such as subzero temperatures and high salinity.