Taxonomic diversity of fungi in the samples of the active layer of Antarctica was investigated using conventional microbiological techniques and metagenomic analysis of total DNA extracted from environmental samples. The list of Antarctic microscopic fungi was expanded, including detection of the species representing a portion of the fungal complex which is nonculturable or sterile on conventional nutrient media.

По результатам анализа клоновых библиотек двух областей гена 16S рРНК рассмотрены сообщества архей многолетнемерзлых пород острова Кинг Джордж и оазиса Бангера (Антарктида), содержащих разное количество биогенного метана. Во всех горизонтах обнаружены филотипы, принадлежащие к метаногенным археям.

Изучено таксономическое разнообразие грибов в образцах деятельного слоя Антарктиды с использованием традиционных микробиологических методов и метагеномного анализа суммарной ДНК природных образцов. Расширен перечень микроскопических грибов Антарктиды, в т.ч., за счет обнаружения видов, представляющих некультивируемую или стерильную на традиционных питательных средах часть грибного комплекса.

Метагеномное исследование образцов многолетнемерзлых пород Колымской низменности, возраст которых составляет 20–35 тыс. лет, проведенное с использованием набора “Geneclean for Ancient DNA kit” (“Bio101”, США), выявило 8 филотипов, относящихся к филумам Actinobacteria и Proteobacteria. Анализ клоновой библиотеки генов 16S рРНК показал, что наибольшее количество клонов (48 и 29%) представлено родами Arthrobacter и Bradyrhizobium соответственно. Впервые обнаружены микроорганизмы родов Williamsia, Bradyrhizobium, Filomicrobium и Hansschlegelia в составе древних микробных сообществ данных экосистем. Анализ генов 16S рРНК изолятов выявил наличие среди них организмов - представителей филумов Firmicutes и Actinobacteria, как филогенетически близких к известным видам, так и явных представителей новых таксонов. Электронно-микроскопический анализ in situ тотальных препаратов изучаемых образцов показал наличие неповрежденных бактериальных клеток различных морфотипов.

The relationships between climate changes and the soil cover are analyzed. The greenhouse effect induced by the rising concentrations of CO 2 , CH 4 , N 2 O, and many other trace gases in the air has been one of the main factors of the global climate warming in the past 30–40 years. The response of soils to climate changes is considered by the example of factual data on soil evolution in the dry steppe zone of Russia. Probable changes in the carbon cycle under the impact of rising CO 2 concentrations are discussed. It is argued that this rise may have an effect of an atmospheric fertilizer and lead to a higher productivity of vegetation, additional input of organic residues into the soils, and activation of soil microflora. Soil temperature and water regimes, composition of soil gases, soil biotic parameters, and other dynamic soil characteristics are most sensitive to climate changes. For the territory of Russia, in which permafrost occupies more than 50% of the territory, the response of this highly sensitive natural phenomenon to climate changes is particularly important. Long-term data on soil temperatures at a depth of 40 cm are analyzed for four large regions of Russia. In all of them, except for the eastern sector of Russian Arctic, a stable trend toward the rise in the mean annual soil temperature. In the eastern sector (the Verkhoyansk weather station), the soil temperature remains stable.

Рассматриваются проблемы воздействия изменений климата на почвенный покров. Показано, что одной из главных причин потепления климата в последние 30–40 лет является парниковый эффект, вызываемый повышающейся концентрацией в атмосфере СО2, СН4, N2O и других микрогазов. В статье предпринята попытка представить в общих чертах связь между глобальными изменениями климата и состоянием почвенного покрова. На примере сухостепной зоны России рассмотрена эволюция почв под влиянием климатических изменений. Рассмотрены возможные изменения углеродного цикла в результате увеличения в атмосфере концентрации СО2. Повышающаяся концентрация СО2 в атмосфере может рассматриваться, как фактор атмосферного удобрения, способствующего увеличению продуктивности растений и дополнительному поступлению в почвы органических остатков и усилению активности почвенной микрофлоры. Наибольшей скоростью изменения под влиянием климата обладают режимы температуры и влажности, газовый состав, биотические параметры и некоторые другие. Для территории России, более половины которой занято самой чувствительной к изменениям климата оболочкой – вечной мерзлотой, это имеет первостепенное значение. На основе анализа собранной базы данных в настоящей статье приведены обобщенные многолетние данные по температуре почвы на глубине 40 см по четырем крупным регионам России. Во всех регионах, за исключением Восточного сектора Арктики показан устойчивый тренд повышения среднегодовой температуры. В восточном секторе Арктики (метеостанция Верхоянск) наблюдается стабильный температурный режим почв независимо от глобального потепления.

A comparative study of the structure of micromycete complexes has been performed. The samples of micromycetes were taken by boring from unique habitats: cryopegs (lenses of non-freezing hypersaline water in ancient permafrost horizons) and permafrost Arctic sediments of different age enclosing these cryopegs. The possibility of characterizing the above habitats by the structure of specific complexes of microscopic fungi using qualitative and quantitative indices at extremely low numbers of these organisms was demonstrated.

Comparative characterization of Geomyces isolates was performed. The isolates were obtained from Arctic cryopegs and the surrounding ancient marine deposits, from nonsaline permafrost soils, and from temperate environments. Microbiological (cultural and morphological) and molecular criteria were used to confirm the identification of the isolates as Geomyces pannorum. The isolates from cryopegs and surrounding marine deposits were shown to differ from those obtained from nonsaline soils and temperate environments in their ability to grow at negative temperatures (−2°C) under increased salt concentration (10%). The results are discussed in relation to the possible inheritance of the adaptive characteristics acquired in specific environments.

An algologically pure culture of the green alga Trebouxia, a phycobiont of cryptoendolithic lichens, was isolated from sandstone samples collected in the high-altitude polar regions of Antarctica. The absorption and second-derivative absorption spectra of acetone extract of the Antarctic phycobiont cells were studied in comparison with those of a Trebouxia phycobiont isolated recently from a Parmeliaceae lichen in the Mid-European climatic zone. The cells of the Antarctic phycobiont were characterized by a lower content of chlorophyll a and a higher ratio of chlorophyll b and carotenoids to chlorophyll a as compared to the Mid-European phycobiont. Furthermore, the carotenoids of the Antarctic phycobiont were more diverse. The low-temperature fluorescence spectra of the Antarctic phycobiont were characterized by an increased intensity of the short-wavelength fluorescence peak of chlorophyll aand a diminished intensity of fluorescence in the long-wavelength spectral region.

An algologically pure culture of the green alga Trebouxia, a phycobiont of cryptoendolithic lichens, was isolated from the sandstone samples collected in the high-altitude polar regions of Antarctica. The absorption and the second-derivative absorption spectra of the acetone extract of the Antarctic phycobiont cells were studied in comparison with those of the Trebouxia phycobiont isolated recently from the Parmeliaceae lichen in the Mid-European climatic zone. The cells of the Antarctic phycobiont were characterized by a lower content of chlorophyll a and a higher ratio of chlorophyll b and carotenoids to chlorophyll a as compared to the Mid-European phycobiont. Furthermore, the carotenoids of the Antarctic phycobiont were more diverse. The low-temperature fluorescence spectra of the Antarctic phycobiont were characterized by an increased intensity of the short-wavelength fluorescence peak of chlorophyll a and a diminished intensity of fluorescence in the long-wavelength spectral region.

The algologically pure cultures of the green–brown cyanobacterium Chroococcidiopsissp. and three cyanobacteria of the genus Gloeocapsa, the blue–green Gloeocapsa sp.1, the brown Gloeocapsa sp.2, and the red–orange Gloeocapsa sp.3, were isolated from sandstones and rock fissures in the high-polar regions of Antarctica. These cyanobacteria are the most widespread phycobionts of cryptoendolithic lichens in these regions. The comparative analysis of the absorption and the second-derivative absorption spectra of the cyanobacteria revealed considerable differences in the content of chlorophyll a and in the content and composition of carotenoids and phycobiliproteins. In addition to phycocyanin, allophycocyanin, and allophycocyanin B, which were present in all of the cyanobacteria studied, Gloeocapsa sp.2 also contained phycoerythrocyanin and Gloeocapsa sp.3 phycoerythrocyanin and C-phycoerythrin (the latter pigment is typical of nitrogen-fixing cyanobacteria). The fluorescence spectra of Gloeocapsa sp.2 and Gloeocapsa sp.3 considerably differed from the fluorescence spectra of the other cyanobacteria as well. The data obtained suggest that various zones of the lichens may be dominated either by photoheterotrophic or photoautotrophic cyanobacterial phycobionts, which differ in the content and composition of photosynthetic pigments.