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Comparative integral assessment of the biological characteristics of the water samples of ice-covered Antarctic Lake Untersee was carried out using a new nanobiotechnological approach based on registration of biogenic nanoparticles of reduced silver Ag. Formation of reduced silver nanoparticles occurred in all samples containing aboriginal microorganisms, while nanoparticles were not formed in the samples from which bacterial cells were removed. Size distribution of biogenic silver nanoparticles varied in the samples from five water horizons. The method proposed provides for rapid detection of live microbiological objects in the samples by detection of formation of biogenic nanoparticles of reduced silver. The method was termed OBNG (Observation of Biogenic Nanoparticles Growth). [ABSTRACT FROM AUTHOR]

Comparative analysis of the presence of bacteriophages was carried out for the water column of a permanently ice-covered, extremely oligotrophic Lake Untersee (East Antarctica) and the ancient ice wedge of the Mamontova Gora outcrop (Aldan River, Central Yakutia). Microscopy revealed bacteriophages in the Mamontova Gora ice samples and in the lysates of the pure cultures of phage-sensitive bacteria isolated from the same samples. Bacteriophages isolated from these cultures were filamentous and interacted with bacteria as moderate (lysogenic) phages. A similar filamentous bacteriophage was isolated from the Lake Untersee water column. The highest morphological diversity of bacteriophages was revealed by microscopy in the oxic Lake Untersee water column in the chemocline zone (70-76 m) and in the sulfide layer (85 m). Detection of similar filamentous bacteriophages in a relic ice sample and in the samples from Antarctic Lake Untersee indicate wide occurrence of bacteriophages and lysogeny in microbial communities of low-temperature ecosystems. [ABSTRACT FROM AUTHOR]

The article presents information on a study conducted to determine the importance of bacteriophage population of aerobic microorganism in Untersee lake located in Antarctica. The study revealed the importance of bacteriophages in the formation of microbiota as well as maintenance of biogeochemical and ecological processes which occurs in the aquatic ecosystems.