Home – Home – Jornals – Numerical Analysis and Applications 2016 number 1

We present results of study of the geologic structure and age sequence of formation of the Late Neoproterozoic-Early Paleozoic plagiogranitoid and gabbroid associations in the Bumbat-Hairhan intrusive area of the Lake Zone in Western Mongolia. The petrogeochemical characteristics of the plagiogranitoids provide information about the conditions of formation of their parental melts at the island-arc and accretion-collision stages of the regional evolution. They also help to establish the main magma-generating sources as well as the major mechanisms of large-scale formation of granitoid melts and their relationship with ore generation processes. According to the trace-element and REE patterns and indicative ratios of these elements, the plagiogranitoids are subdivided into high- and low-alumina ones. Among the island-arc plagioranitoids (551-524 Ma) of the Bumbat-Hairhan area, high-alumina varieties are the most widespread. They resulted from the partial melting of metabasites in equilibrium with garnet-containing restite at ≥15 kbar during their subsidence into the subduction zone. In geochemical features these plagiogranitoids are similar to high-Si adakites of different world regions. Island-arc low-alumina plagiogranitoids are scarcer. Their geochemical characteristics indicate that the parental melts were generated through the partial melting of metabasites in the basement of the island-arc system in equilibrium with amphibole-containing restite at ≤8 kbar. Plagiogranitoid associations of the accretion-collision stage (511-468 Ma) are the most widespread in the Bumbat-Hairhan area. They are subdivided into high- and low-alumina ones. According to the contents of trace elements and their indicative ratios, the low-alumina plagiogranitoids resulted from the partial melting of metabasites in equilibrium with plagioclase-containing restite at ≤8 kbar in the upper part of the collisional structure, and the high-alumina ones were generated through the melting of metabasites in the basement of thick crust in equilibrium with garnet-containing restite at ≥15 kbar. Geochronological studies in the Bumbat-Hairhan area revealed two stages of ore-generating processes spatially and temporally related to the formation of low-alumina plagiogranitoids. The early stage (518 ± 5 Ma), development of vein Cu(Au) mineralization, coincided in time with the formation of island-arc low-alumina plagiogranitoids of the Darbi massif (~524 Ma). The late stage (456 ± 4 Ma), formation of porphyry Cu-Mo (Au) mineralization, was synchronous with the formation of the low-alumina plagiogranites at the accretion-collision stage (~468 Ma).

A U-Pb isotope analysis has revealed zircons, dated at ~510−490 and ~430−400 Ma, in granitoid intrusions on the eastern slope of the Kuznetsk Alatau Range (Batenev Ridge). This suggests two stages of regional granitoid magmatism: Middle-Late Cambrian and Silurian-Early Devonian. The ages of two zircon grains from the rocks of the Tigertysh pluton are ~1.9 and ~2.6 Ga; they suggest the involvement of fragments of the Paleoproterozoic continental crust in magma generation. The granitoids, independently of their age, are mostly products of rocks of the calc-alkalic (K₂O/Na₂O ≈ 0.5−1.7) series. In the proportions of alumina, calcium, and alkalies most of them correspond to I-type granites (A/CNK ≤ 1.1) with reduced Fe/(Fe + Mg) values and contents of HFSE, including REE (ΣREE ≈ 100−300 ppm). The trace-element patterns of the rocks point to the possible participation of both IAB and OIB in magma genesis. Presumably, the influence of the within-plate component increased as a result of the superposition of plume on accretion-collisional structures, and their melting might have favored the preservation of geochemical features of subduction magmatism in the granitoids. The isotopic inhomogeneity (ε_Nd(T) = 2.3−4.8, (⁸⁷Sr/⁸⁶Sr) T ≈ 0.7036−0.7051) of granitoid complexes suggests the heterogeneous composition of the sources of their material, which consisted of the matter of moderately depleted (PREMA) and enriched (EM) lithospheric mantle and crustal substrate, mixed in different proportions. Some products of the regional alkali-basic magmatism are coeval with the Cambrian granitoids of the Kuznetsk Alatau and are similar to them in isotope composition. This magmatism confirms the interaction of plume with the active continental margin at the Caledonian stage of evolution of the Central Asian Fold Belt.

We present data on the geologic setting, mineral composition, and conditions of metamorphism of volcanics of andesite-dacite-trachyrhyodacite, leucobasalt-basalt, basalt-andesite-basalt-trachyandesite, and basalt associations in the Yenisei amphibolite-gneiss complex of the Angara-Kan terrane. We have determined the age of zircon (SHRIMP-II U-Pb dating) from two samples of volcanics of the andesite-dacite-trachyrhyodacite association. The volcanics formed in the Late Paleoproterozoic (~1.74 Ga) and were metamorphosed at 750 Ma. Inherited zircon and the Sm-Nd model age (2.4-2.5 Ga) of intermediate-felsic volcanics testify to their formation predominantly from the ancient crustal source. The Late Paleoproterozoic (1.78-1.74 Ga) sedimentation and volcanism in the Angara-Kan terrane followed the main collision events: high-temperature metamorphism (1.89-1.87 Ga) and formation of the first-phase granitoids of the Taraka massif (1.84 Ga). The volcanics have a predominantly bimodal character and belong to the tholeiitic and subalkalic series; this testifies to their formation in an extension setting. The formation of the volcanics of the Yenisei complex correlates with the intrusion of the intraplate granites of the Taraka massif, whereas the terrigenous sediments correlate with the sediments of the middle Subluk Group in the Urik-Iya graben. The rocks of the Yenisei complex are characterized by inhomogeneous metamorphism, which corresponds to the conditions of transition from epidote-amphibolite to amphibolite facies and to the entire PT -range of the amphibolite facies.

Biostratigraphic subdivision and correlation of Ordovician different-facies sections on the western slope of the Southern Urals are carried out based on conodonts and chitinozoans. Upper Ordovician conodonts are defined in the West Zilair zone, in a carbonate-terrigenous section near Nabiullino Village. They belong to important cosmopolitan taxa which permit distinguishing biostratigraphic units corresponding to the North Atlantic standard conodont scale. Successions of Middle and Upper Ordovician conodont and chitinozoan assemblages are detected in the terrigenous-siliceous sections of the East Zilair zone. Middle Ordovician chitinozoans are found in the Uraltau zone, in the metamorphic rocks of the Belekei Formation of the Suvanyak complex, previously assigned to the Precambrian. Most of the taxa in the conodont and chitinozoan assemblages have a good correlation potential owing to their wide geographic range. A positive δ¹³C excursion of 3.3 ‰ has been first recorded in the Nabiullino section (West Zilair zone), suggesting the initial stage of the HICE isotopic event in the Southern Urals. The development of shallow-water conodont biofacies at the top of the section suggests a sea level fall in the late Ordovician.

We present new data on the structure and age of the upper Permian strata in the basin of the Setorym River (tributary of the Vostochnaya Khandyga River) in the South Verkhoyansk region, represented by the Imtachan Formation and the lower part of the Nekuchan Formation. Based on the new findings of bivalve fossils from the Intomodesma costatum Zone, as well as on the study of carbon isotopes in the shells and carbon isotopes of the organic matter of the host mudstones, we have for the first time proved the completeness of the Permian section. The detailed description of the contact between the Imtachan and Nekuchan Formations bears evidence for a certain continuity of the lithologic characteristics of the sandstones. The sharp lithologic contact between the formations reflects not a regional sedimentation hiatus but a shift of depositional settings from the upper parts of a delta to the deep shelf, caused by forced marine transgression. It is concluded that there was no long-term hiatus between the accumulation of the Imtachan and Nekuchan Formations. Images of the most characteristic species of bivalves and crinoids from the Imtachan Formation are presented.

The study explored the taxonomic composition of foraminiferal assemblages from cores sampled in the Sil’ga and Yamal-Tyumen’ facies regions-the southern and southwestern West Siberian sedimentary basin. A complete sequence of biostratons was established for the Callovian-Kimmeridgian sediments of the southwestern West Siberian Lowland and was correlated with the units of the General Stratigraphic Scale. A number of biostratons have been revealed for the south of West Siberia. The biofacies analysis of the foraminiferal assemblages revealed that the Yamal-Tyumen’ facies region belonged to a relatively deep marine environment, far away from the Jurassic Sea littoral zone, in the Callovian through the Kimmeridgian and that the Sil’ga facies region was a relatively shallow marine environment in the Oxfordian through the Middle Volgian.

The paper presents palynologic and paleomagnetic characteristics of three West Siberian horizons are presented: Zhuravka (Upper Oligocene, Chattian), Abrosimovka, and Beshcheul (Lower-Middle Miocene, Aquitanian, Burdigalian, Langhian, and Serravallian). We consider the distribution of dinocysts of the genus Pseudokomewuia in the stratotype section of the Zhuravka Horizon (Zashchitino Village) and in the section of borehole 13 (Chelyuskintsev Village), which exposes the Turtas, Abrosimovka, and Beshcheul Formations. Similar compositions and structures of dinocyst assemblages and similar palynofloras in the Turtas and Abrosimovka Horizons, as well as the sedimentation environment and cyclic structure of lacustrine deposits, suggest that the Paleogene/Neogene boundary should be localized at the base of the Beshcheul Horizon. We propose to include the Abrosimovka Horizon into the Upper Oligocene (upper Chattian). The data are correlated with the regional paleomagnetic scale. These views should be reflected in a new regional stratigraphic chart for the Paleogene-Neogene deposits of the West Siberian Plain.

We performed a regional analysis of the effect of anthropogenic (acid precipitation) and natural (climatic changes, endogenous methane) factors on the hydrochemical composition and phytoplankton of mountain lakes in East Siberia for the last 210 years. The lacustrine diatom community responded to the intense acid precipitation that led to the acidification of lakes in Europe and North America in 1950-1985: Cyclotella-complex was partly replaced by more pH-tolerant species of diatoms, such as Aulacoseira lirata, A. italica, and Tabellaria flocculosa. This anthropogenic impact, however, was not dramatic for the ecosystem of mountain Lake Oron. The diatom records distinctly show a tendency for the reduction of lacustrine-alga population since the end of the Little Ice Age. We assume that the decrease in the Oron bioproductivity was mainly due to a deficit of nutrients caused by the inflow of ultrafresh waters from the thawing glaciers, snow patches, and seasonal snow cover of the Kodar Ridge during the global warming in the Northern Hemisphere. In addition, the changes in the lake ecosystem might have been accelerated by emissions of endogenous methane.

A method for three-dimensional modeling of pulsed soundings using a fast Fourier transform is developed: instead of the time-domain problem, it is proposed to solve a set of frequency-domain problems obtained by processing the original excitation pulse by a fast Fourier transform. The error of the proposed method compared to the method of solving the time-domain problem is numerically estimated for a model problem with a sinusoidal signal.

The area of the Chon-Aksu and Kichi-Aksu grabens abounds in seismic deformation produced by historic and prehistoric events, among which the great Kemin (Kebin) earthquake of 1911, with a magnitude of Ms ≈ 8 and a shaking intensity of I ₀ = 10-11, generated by the Aksu fault. Trenching across a fault scarp of the 1911 event has revealed signatures of reverse slip resulted from another earthquake that occurred about 3000 years ago. Traces of a large event at ~12,700 yr BP appear in sediments of a tectonically dammed lake. The trenching results, along with radiocarbon dating and published evidence, show the Late Pleistocene-Holocene history of the Aksu fault to comprise prolonged quiescence periods separated by large earthquakes or earthquake clusters at 19,500-20,000, 12,700, 4000-3000, and <850 yr BP (including the 1911 Kemin shock).

Conductivity anisotropy of the lower mantle presumably caused by phase change of dielectric magnesiowьstite at depths of 1500-2000 km is detectable from jerks. Jerks are induced by currents in the fluid outer core, propagate upward from the CMB through anisotropic conducting mantle, and appear on the Earth’s surface. The surface jerk patterns are studied theoretically from the potential of the geomagnetic field presented as a sum of magnetic and electric modes. Equations for the fields of both modes and their relationship in a weakly anisotropic earth are obtained by the perturbation method. The field potential is expanded into a series of spherical harmonics, and the equations are solved in the frequency and time domains. The surface jerk responses can be inverted to retrieve anisotropy parameters; the goal function in the inversion may correspond to misfit between the model and experimental values either along the horizontal or vertical components.

Results of numerical simulation of exciting a copper vapor laser (CVL) by a pulse-periodical inductive (electrodeless) discharge are presented. A variant of CVL with a ring active volume of the discharge chamber is studied. It is shown that such a chamber to a higher degree satisfies all the requirements for pumping by the inductive method than an ordinary cylindrical chamber. High output characteristics of lasing obtained in the numerical simulation confirm the possibility of CVL efficient pumping by the new inductive method.

Evolution of spatial and energy characteristics of start pulse with energy of 0.8 mJ and duration of 2 ps in the amplifier of THL-100 laser system have been studied experimentally and by numerical simulation. Laser radiation energy E = 2 J was obtained experimentally. In this work we present a 3D amplification model of conically diverging laser beams, which takes into account the spatial inhomogeneity of the pump and the geometry of THL-100 laser system amplifier. Description and the test results of the model are submitted. At the start pulse energy of 0.8 mJ the calculated radiation energy at the amplifier output reaches 2.4 J. Simulation results show that maximal intensity of the laser radiation in this mode reaches P = 60 GW × сm^-2. Evolution of energy and space-time structure of the laser pulse in the amplifier was investigated. It is shown that in the ideal case (excluding the processes of nonlinear interaction of laser beam with the active medium), at the start pulse energy of 5 mJ, the energy of the laser radiation at the output of the amplifier is increased to E _out = 3.8 J. In this mode, the maximal radiation intensity reaches a value of I = 148 GW × сm^-2.

The experimental results of the study of population inversion in the resonant electronic transition B³П _g -A³å _u⁺ of nitrogen ions by optical pump of air and pure nitrogen by a femtosecond laser pulse at a wavelength of 950 nm are presented. It is shown that the inversion results from selective settling of N₂⁺ (B²å _u⁺,n¢=0) excited state during multiphoton excitation of the autoionization state of the nitrogen molecule with energy of 18.7 eV. Seed photons for superradiance at transitions of molecular nitrogen ions are photons of the axial supercontinuum occurring in a filament at the corresponding wavelengths. The mode of the superradiance at the wavelength  = 358.4 nm, referred to the transition of the CN molecules, was implemented.

The results of measurement and calculation of parameters of radiation at  = 475 nm after compression in glass are presented. It is shown that there are three ranges of the energy density of the radiation entering to the compressor. In the first range of low intensity (energy density is 1-5 mJ/cm²), the influence of non-linearity on the output beam parameters is insignificant. The second range of moderate intensity (energy density is 5-10 mJ/cm²) is characterized by a significant loss of energy during the propagation of the output beam. The third range of increased intensities (energy density is 20 mJ/cm² or more) is characterized by a complete destruction of the spatial structure and the spectral composition of the output beam.

In this work, we showed that doping of sesquioxide based ceramics (for instance, Y₂O₃) by heterovalent ions leads to altering of polarizations. It results in variation of refractive index and wave-front distortion due to presence of volumes with increased content of heterovalent ions. It also contributes to lowering of transmittance and increasing of scattering in ZrO₂-, HfO₂-, or CeO₂-doped Y₂O₃ ceramic samples.

Investigations of 1Nd : Y₂O₃ + 6HfO₂, 1Nd : Y₂O₃ + 10HfO₂, 3Yb_{: Y2O3 + 5ZrO2, and 5Yb :Y2O3 + 5HfO2 laser ceramics with typical optical inhomogeneities called "orange peel" are presented. The diameter and thickness of samples were, respectively, 11 and 1.7-2.0 mm. Characteristic sizes of optical inhomogeneities causing the effect of "orange peel" were in a range from 10 to 300 mm.}

Results of experimental investigations of dependence of energy, temporal, spectral, and spatial characteristics of inductive HF laser generation on pumping conditions are presented. Gas mixture of hydrogen with F₂ or NF₃ or SF₆ and their mixtures with helium and neon were used as an active medium. A maximum generation energy of 19 mJ in a gas mixture He :_{H2 : NF3 - 45 :1 : 4 under pressure of 42 Torr has been achieved. Pulse duration (FWHM) was 0.42 ms that corresponded to a pulse peak power of 45 kW. Spectral composition of inductive HF laser generation has been investigated for the first time. Lasing spectrum consisted of seven groups of bands near 2732, 2763, 2798, 2835, 2873, 2893, and 2913 nm. Lasing shape had a ring form with diameter of about 20 mm and thickness of 4-5 mm. The laser had high stability when operating in pulse periodic regime. The light pulse amplitude divergence was within 5-6%.}

Laser parameters in Не-Ar(Kr, Xe)-F₂ and He-F₂ gas mixtures under pumping by runaway electron preionized diffuse discharge (REP DD) are studied. It is shown that the REP DD can be a source of efficient laser emission on XeF^* and KrF^* molecules. Laser action on transitions of molecular fluorine in the VUV range at 157 nm was obtained in REP DD for the first time. It was shown that high uniformity of REP DD allows one to increase laser pulse duration on rare gas fluoride molecules. Laser parameters obtained in the REP DD are comparable with those obtained under pumping by commonly used transverse discharges with preionization.

Gasdynamic processes that take place at a pulse-periodic discharge initiated by runaway electrons in atmospheric pressure air were studied with a laser monitor based on a CuBr laser. Voltage pulses (U = 13 kV, FWHM is 10 ns, front duration is 4 ns, negative polarity, f = 60-3200 Hz) applied to a cone copper cathode with diameter of cone base, apex angle, and corner radius of cone apex of 6 mm, 30°, and 0.2 mm, respectively. A flat copper anode was located at a distance of 2 mm from the cathode. It was established that products of discharge plasma with copper vapors are transferred in radial direction along a surface of the flat anode during 2.5 ms to a distance of 24 mm. The temperature of air heated by the discharge in the moment of its expanding was ~ 1 × 10³ K. It was shown that use of the laser monitor in transmitted light allows obtaining contrast images of optical inhomogeneities that arise at a gas discharge.

In this paper, the investigation results of gain characteristics of a CuBr laser with an unstable cavity are shown. The effect of the losses in the feedback channel of the unstable telescopic resonator with lateral output radiation was investigated. The possibility of allocating one laser wavelength through the use of band-pass filters in the cavity feedback channel was demonstrated.

An iterative method of finding a singular solution to the problem of minimizing resource consumption has been developed. This method is based on the information about the finite control structure. A condition for existence of a singular solution is obtained. The limit value for transferring the time between the normal and the singular solutions is found. A relation between the variations of the control switching moments and the variations of the initial conditions of the adjoint system is determined. A system of linear algebraic equations relating the variations of the initial conditions of the adjoint system to the variations of the phase coordinates from a given final state of the system is obtained. The computational algorithm, the modeling results and the numerical calculations are presented.

The new algorithms of statistical modeling of radiative transfer through different types of stochastic homogeneous isotropic media have been created. To this end a special geometric implementation of «the maximum cross-section method» has been developed. This implementation allows one to take into account the radiation absorption by the exponential multiplier factor. The dependence of a certain class of solution functionals of the radiative transfer equation on the correlation length and the field type is studied theoretically and by means of numerical experiments. The theorem about the convergence of these functionals to the corresponding functionals for an average field with decreasing the correlation length up to zero has been proved.

In this paper, we investigate the accuracy of estimates of the first moments of a numerical solution to SDE with the Wiener and the Poisson components by the generalized Euler explicit method. The exact expressions for the mathematical expectation and variance of the test SDE solution are obtained. These expressions allow us to investigate the dependence of the accuracy of estimates obtained by Monte Carlo method on the values of SDE parameters, the size of an integration step, and the size of an ensemble of simulated trajectories of the solution. The results of the numerical experiments are presented.

The soils of the study area function in different temperature regimes: under the influence of permafrost (turbic histic cryosol and cryic eutric histosol) and long-term seasonаl freezing (Albic Podsol). Sporadic permafrost defines the differences in temperature regimes. All soils were characterized by low values of carbon dioxide effluxes (an average of 160 mgCO₂/(m²⋅h)) indicating their low biological activity. The lack of easily accessible carbon for microorganisms was detected in all investigated soils by the C_mic : C_org ratio despite the high stocks of organic matter. The value of CO₂ emission and the C_mic : C_org ratio were “site-specific” for the region of investigation and may be used as indicators of environmental changes. Peat cryogenic soils represent a unique natural object and provide functional diversity and integrity of northern taiga ecosystems of West Siberia.

The basic tendencies of territorial changes in bird communities of the middle taiga of the Central Siberian Plateau are connected with the differences in forest cover percent, productivity, swampiness, developing of shrubs, abundance of water and on how much the land is built-up. On the whole, these factors are the same as in the West Siberian and Central-Yakutsk plains, although there are some differences. Namely, only West Siberia is characterized by the communities living on upper swamps and low-inundated meadows in combination with the lowland swamps. In Central Siberia forest ornithocomplexes are the most diverse, mainly at the expense of the communities living in open forests and post-fire areas at different stages of regeneration. The ekoton ornithokomplex type was distinguished only for Central Yakutiya. In North Ural, forest cover percent and tree species composition are still significant for the formation of ornithocomplexes, but the impact of high-altitude zonation and the productivity of biocenoses and developing of shrubs in the habitats connected with it are also becoming important.

Data on the species composition and distribution of ferns in the present-day periglacial zone of the Aktru, Karagemsky, Akkem, Sophiysky, Gebler and Taldurinsky glaciers in the Central Altai were presented. Sixteen species of ferns were found and confirmed by herbarium specimens. Botrychium lunаria (L.) Sw., Cystopteris dickieanа R. Sim, C. fragilis (L.) Bernh. and Polystichum lonchitis (L.) Roth were the most tolerant to the severe conditions of the high mountains. The distribution of ferns in the centers of present-day glaciation was related mostly to the occurrence of rocks. Colonization of the periglacial zone by ferns occured only by means of spores, initially by their dispersion from the locations far from the periglacial zone. Further colonization and migration of species following the retreating glaciers were possible by means of spores produced by sporophytes growing in the periglacial zone. Germination of spores and development of gametophytes and sporophytes in severe conditions of the periglacial zone occured mainly in local micro-niches providing protection in the cold season and sufficient amount of moisture in the warm season.

The data on meteorological parameters variation in the Altai-Sayan region in XX-XXI century were analyzed. Significant trends characterizing the dynamics of the average temperature, precipitation and dryness index SPEI were revealed. Growing wildfire frequency in the study area since the end of XX century was detected. Annual variation of wildfires had phase concurrency with the dynamics of mean temperature deviations and climate dryness and negatively correlated with averaged precipitation data. Rising of wildfire frequency was observed for the period of the XX - the first decade of the XXI century. The spatial re-distribution of wildfires in the Altai-Sayan region in the beginning of the XXI century was determined.

Ecological structure of ground beetles and its dynamics during the transition of ground beetles from one habitat to another due to felling and subsequent reforestation were studied. The regularities in the formation and development of ground beetles community in the early stage of secondary succession on the felling site were determined. The simplest indices of diversity, species abundance, distribution and dominance were used. Species richness of ground beetles on the felling site increased from 28 to 41 species a year after felling. In four years it decreased to 36 species. According to the ecological preference, the basis of the ground beetles complex on the forest site before felling was formed by spring-breeding forest species. Four years after felling the proportion of forest species decreased from 73,4 to 65,7 %, and the significance of forest-marsh species and meadow-field species increased. The number of summer-breeding and autumn-breeding species also increased. The species and quantitative composition of ground beetles on the felling area during the first year was mostly determined by a neighboring forest. In the following years a separate biocenosis was formed on the site, and the influence of the forest diminished.

A hypothesis of range formation of the earthworm Eisenia sibirica Perel et Graphodatsky, 1984, which is an endemic species of Altai-Sayansk mountain system and is also found on the adjacent plains of Siberia across the valleys of the rivers, was suggested. Limited distribution of the species can be connected with insufficient cold hardiness of the worm stage (-10…-12 ^оС). Plains of Western Siberia lie in the isotherm area of minimum soil temperatures at a depth of 3 cm - -12…-14 ^оС, i. e., on average 2-4 ^оС below tolerable limits for this species. Foothills and mountain soils are warmer, since they obtain much more solid precipitations. Low soil temperatures of the plains apparently “lock up” this species within Altai-Sayansk system. At the same time there is reason to consider the northernmost locations of E. sibirica to be relict.

The diet of the American mink near the lakes and mountain rivers of the Southern Urals was studied. The structure and dynamics of the minks’ feeding near the lakes and mountain rivers differed significantly. On mountain rivers the minks’ diet depended on the abundance of small mammals on the river bank. The abundance of small mammals in each season was determined by the peculiarities of the hydrological regime.

Seasonality of epidemic and epizootic processes of tick-borne encephalitis (TBE) and borreliosis among the populations of Ixodes persulcatus and Ixodes pavlovskyi was studied. The study was carried out in 2011-2012 on the flatland part of Toguchin and in the vicinities of Akademgorodok in Novosibirsk, on the border between the forest and forest-steppe zones of the Ob region. The results obtained for I. persulcatus did not contradict the previously published studies. The starting point and peak of mass activity of I. pavlovsky ticks were registered later (the III decade of May) than that of I. persulcatus ticks . Seasonal variations in the physiological age of I. pavlovsky ticks were similar to that of I. persulcatus ticks. The only exception to this was detected in the III decade of April when young specimens prevailed in the population of I. pavlovsky ticks in contrast to the I. persulcatus population. The large influence of I. persulcatus on the circulation of TBE was shown, as well as the influence of I. pavlovskyi on the spreading of Borrelia burgdorferi s.l.

External ecological factors that have an impact on a population of wild reindeer on the Taimyr Peninsula were surveyed in the paper. The factors were estimated according to their influence on the abundance of reindeer in the population. The key factors were examined with relation to bioenergetics. In view of the potential resumption of anthropogenic influence due to further industrial development of Taimyr the population conservation strategy was proposed.

The article presents the results of an experimental study on the bream Abramis brama L. exposed to polychlorinated biрhenyls (PCBs) administered with food. Responses of the components of hepatic biotransformation system (activity of ethoxyresorufin-O-deethylase and glutathione-S-transferase), antioxidant system (superoxide dismutase and catalase activity) and lipid peroxidation system (conjugated dienes and malonic dialdehyde contents) were studied. It was determined that the 2 mg/kg dose of PCBs did not cause permanent physiological alterations in the bream exposed to such feed for 14 days. Apparently, at these exposure conditions hepatic protection systems of the bream were able to suppress effects of xenobiotics and keep destructive processes on a stable moderate level.

The study area covered the West Siberian plain from the Urals to the Yenisei River, and the same lane further southwards to the borders of the former USSR in 1991, including a part of the Altai-Sayan mountain country, Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan and Tajikistan. On this site we analyzed the results of ornithogeographic surveys carried out on routes with a length of 63 thousand km in 3140 habitats from May 16 to July 31 in the period from 1936 to 2013. More than 100 specialists participated in the study. The collected data were averaged according to the contours of natural-geographical maps. The subsequent cluster analysis revealed the presence of 3 systems (rows) of bird communities of undeveloped and developed land, and water and riparian communities. Within the first system 8 types of communities were determined: 1 - Tundra; 2 - Forest-tundra; 3 - Forest; 4 and 5 - West Siberian: 4 - Meadow-steppe and 5 - Semidesert-steppe; 6 and 7 - Asian: 6 - North-desert-steppe and 7 - South desert; 8 - High-mountain. The borders of their distribution did not coincide with the zonal borders. In the second and third systems 7 and 6 types of communities were allocated respectively. A part of them was divided into 29 subtypes. The heterogeneity of bird communities was determined by 12 environmental factors. The greatest impact was detected for forest cover, building cover and watering cover. The correlation of the bird population variability with all the identified environmental factors amounted to 54 % ± 1 percentage of variance in the similarity matrix. It corresponded with the correlation coefficient of 0.74.

The elemental composition, the content of pigments, proteins, liрids, free amino acids and antioxidants of 5 wild halophyte species in Prieltonye were investigated. Plants differed in systematic location (Chenopodiaceae, Plumbaginaceae, Asteraceae), the type of regulation of salt metabolism (eu-, cryno- and glycohalophytes), life form (annual grasses, shrubs), the water regime (mesoxerophytes, xeromesophytes). A decrease in the ion content of K, Na, Ca among Suaeda linifolia > Salicornia perennаns > Halocnemum strobilaceum > Limonium gmelinii > Artemisia santonica was noted. The reversed pattern was observed for the content of C. The increase in the total content of C in glyco-, cryno- and euhalophytes was accompanied by increased content of total and membrane liрids, proteins and pigments. Halophytes varied considerably in terms of components of the antioxidant system - the content of endogenous proline, soluble protein, liрid peroxidation and the level of total SOD activity. Cluster anаlysis revealed that the differentiation of the studied halophyte species by the type of regulation of salt metabolism was mostly determined by biochemical parameters.

The ecology of the meadow piрit was studied in nаture in the Lower Ob region and on the Yamal Peninsula. Laboratory investigations were carried out under natural and artificial photoperiods. The factors affecting the distribution of the species in the north-eastern limit of its range were analyzed. The meadow pipit is wide-spread in the taiga zone and it does not need any special adaptations for the conditions of forest-tundra and southern tundra. But the species is not adapted to the north tundra environment. Current climate changes define the northern border of its range. The species has no obvious obstacles to spreading to the east.

Migration processes, as well as birth and death rate determine the population dynamics. The main type of migration for rodents is dispersal which has not been studied thoroughly. The typical and maximum distances of species dispersal and permeability of some landscape elements are yet to be found out. The aim of this study was to investigate the dispersal of two most abundant rodent species using a specifically modified method of non-selective marking. It was found out that dispersal distance of a pygmy wood mouse ( Sylvaemus uralensis Pallas, 1811) is larger than that of a bank vole ( Clethrionomys glareolus Schreber, 1780). The determined dispersal distance of the bank vole (up to 2 km) proved the longest for this species. Dispersal process and spatial structure of rodent populations were greatly affected by the territory characteristics. Barrier landscape elements that impede the dispersal, can increase the animals’ local density. The “migrant trap” effect was described for the first time.

Succession stages of epixylic lichens in relation to decomposition of fallen deadwood were studied in Eastern Baikal region. It was found that lichens passed through four stages of epixylic succession: from epiphytic and epixylic to the epigeic stage. It was also determined that lichens could inhibit decomposition of the higher layer of deadwood which served as the substrate to them.

Transformation of ecological environment on coal dumps under the influence of Pinus sylvestris L. lead to formation of three-zone phytogenous fields. The undertree zone was characterized by smoothed temperature conditions, low illumination, accumulation of the forest floor and formation of plentiful undergrowth. The crown zone with high moisture content was characterized by the developed moss cover and low occurrence of undergrowth. The external zone served as a transitional space to background meadow communities and was characterized by the developed grassy cover, high abundance of species and group distribution of undergrowth of P. sylvestris L. Positive, adaptive and negative reactions of grassy plants to phytogenous fields of Scots pine were noted. The majority of species expressed negative reaction.