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To shed light on the problem of trans-biome invasions by microbes, the results of ecological and phylogenetic studies of femtoplankton, the smallest size fraction of plankton formed by viruses and ultramicrobacteria (UMB), were overviewed. Phylogenetic lineages of viruses and UMB were shown to be associated with particular biomes, thus, indicating infrequent trans-biome transitions in the microbial world. Consideration of an alternative hypothesis of widespread cross-colonizations is believed to require a deeper analysis of the factors that form the barrier between biomes and are responsible for the adaptation of microorganisms to different environments.

The phenotypic variation of the morphological traits complex (length of fore and hind wings and diameters of wing eyespot patterns) in the populations of a Trans-Eurasian species Erebia ligea in different landscape and climatic conditions of the Urals region was analyzed. It was shown that protandry, bicyclicity and imago emergence in odd-numbered years were characteristic of E. ligea in the Urals. Geographic variability of imago size was characterized by the cline with a gradual increase in the north-south direction. The chrono-geographical approach allowed us to establish the scale of the observed differences: chronographic variability had the biggest impact on morphological traits; then went sexual and geographical factors. The least effect on the morphological traits complex had the seasonal factor, i.e the moment of imago emergence during the generation flight.

The complete cycle of the structure transformation of shrew model taxocene in southern Sakhalin was revealed by investigations of 2008-2014. It was shown that in the communities of these animals facultative and obligate dominants are absent and a dominant group is formed every year of common species. There are two main patterns of the taxocene structure: the monodominant type, predominating by the long-clawed shrew at low number of other species, and the polydominant type, in which one of the background species plays a role of codominаnt at a lower number of long-clawed shrews. It is found out that the dominanct structure in shrew taxocene is not closely related to the phase of its quantitative dynаmics.

The results of the morphological analysis of ecology and feeding of two sympatric forms (lacustrine and lacustrine-riverine) of the whitefishes inhabiting Lake Taymyr (the Taymyr Peninsula) were presented. It was determined that these forms do not differ in the number of gill rakers on the first brachial arch and the number of lateral line scales, but do differ in plastic features, spawning period and spawning area. At 2-3 years of age the feeding preferences of different forms of whitefish begin to vary. It was supposed that both forms of whitefish occupied Lake Taymyr simultaneously with the ponding of the lake basin. Apparently, the taxonomic status of the sympatric whitefishes from Lake Taymyr is broader than the term “ecological form”.

The study of phytoplankton from lakes, sors, streams and rivers of the Yarayakha River basin with the help of scanning electron microscopy made it possible to extend the Bacillariophyta taxonomic spectrum: 236 specific and intraspecific taxa of diatom algae from 63 genera were detected. A total of 16 species and varieties new for the flora of Russia were recorded, and for 30 forms from 18 genera only the genus was identified. The maximum species diversity was recorded in a stream in the mouth of Yarayakha River (82 species) and in the channel of Khureikhotarka River (105 species). The following species are the most widespread in the waterbodies under study: Cyclotella meneghinianа, Fragilaria exiguiformis, Navicula hanseatica, Neidium bisulcatum, Stauroneis anceps, Thalassiosira inserta, Tabellaria flocculosa.

The article considers the peculiarities of biofilm formation in iron-bearing groundwater in the presence of organic substances with different degrees of bioavailability (yeast extract, peptone, humic substances). Scanning electron microscopy and X-ray analysis helped to identify a biomineral in the crystal structure - goethite (a-FeOOH). It was supposed that admission of surface water with organic substances into the iron groundwater creates a risk of colmatage of aquifer pore space with iron minerals of biogenic origin.

Aquatic vegetation of Hydrochari-Lemnetea and Potametea classes in the Danube-Tisza-Danube hydrosystem (Hs DTD) was studied in 2009-2012, by applying the standard Braun-Blanquet method. The canal network vegetation comprises 14 associations, with Trapetum nаtantis and Ceratophylletum demersi being the most widely distributed. Hs DTD is also a habitat for several important endangered species, which serve as edificators of the following phytocenoses: Nymphaeetum albae, Nymphaeetum albo-luteae, Nymphoidetum peltatae, Trapetum nаtantis, Lemno-Spirodeletum, Salvinio-Spirodeletum polyrrhizae, Lemno-Utricularietum vulgaris, Potametum nodosi, Myriophyllo-Potametum and Najadetum marinаe. In the studied vegetation, we also found an invasive phytocenosis Elodeetum canadensis that did not have an expanding tendency, and Ceratophyllo demersi-Vallisnerietum spiralis that had this tendency, which made monitoring its stands necessary. Physico-chemical analyses of water, conducted at localities in which the studied phytocenoses thrive, revealed that the development and distribution of most phytocenoses is closely linked with specific habitat conditions. Among the studied parameters, the most significant for the phytocenoses differentiation were: pH, alkalinity, COD-MnO₄, BOD₅, NO₃^-, NO₂^-, PO₄^3- and the concentration of total phosphorus.

Four types of mountain forest-steppes were determined for the Altai-Sayan mountain region. It was shown that each type corresponded to a certain bioclimatic sector. The belt structure of each type of mountain forest-steppe was characterized. The ranges of increases in aridity were described: the primary Altaian, the primary Khakas-Tuvinian, and the secondary Khakas-Tuvinian.

The adaptation of Hedysarum theinum to the conditions of the mountainous areas of Western Altai (Kazakhstan) was studied by observing the anatomical features of the leaf blade. The status of 9 populations of Hedysarum theinum was estimated based on the study of 10 anatomical features of the leaf blade. It was found that the combined values of features were the highest in sub-alpine habitats.

The article presents the results of the analysis of ontogenetic and vitality structure of 7 cenopopulations of Oxytropis sulphurea (Fisch. ex DC.) Ledeb. in the high-altitude conditions of the Rydny Altai (Ivanovsky and Prohodnoi ridges) and the Saur ridge. In the study of the demographic structure it was determined that most of the populations from undisturbed habitats were characterized by left-side spectrums with maximums on juvenile or immature individuals. The changes in the structure of the studied ontogenetic spectrums of this species depended largely on the presence of anthropogenic influence. Grazing pressure led to formation of the spectrums with a maximum on g₃-plants. The vitality type of the O. sulphurea populations varied from exuberant to depressed; the depressed and balanced types of vitality prevailed. Intensive seed propagation provides stable existence of O. sulphurea in the high mountain alpine zone. The results of our study showed that O. sulphurea is an alpine-meadow species, which has strict ecological and cenotic propensity for alpine meadows with the prevalence of Festuca krylovianа, Anthoxanthum alpinum, Schulzia crinite and shrub tundras with Dryas oxyodonta.