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A. I. Kopylov A. F. Sazhin E. A. Zabotkina A. V. Romanenko N. D. Romanova P. R. Makarevich M. P. Wenger 《Oceanology》2016,56(6):789-798
The paper considers the concentrations and functional characteristics of viruses, bacteria, and heterotrophic nanoflagellates determined for the first time in the Laptev Sea in August-September, 2014. The abundance of bacteria, viruses, and heterotrophic nanoflagellates varied from 110.1 × 103 to 828.4 × 103 cells/mL, from 384.2 × 103 to 2932.8 × 103 particles/mL, and from 108 to 651 cells/mL, respectively. The daily bacterioplankton production varied from 4.2 × 103 to 381.7 × 103 cells/mL, with an average of 117.6 × 103 cells/mL. Electron transmission microscopy has for the first time shown that the frequency of visibly infected bacterial cells varied from 0.2 to 2.0% (0.8% on average) of NB. The average virus-induced mortality of bacteria was 6.3% of bacterioplankton production, with variations ranging from 1.4 to 16.9%. Grazing on bacteria by heterotrophic nanoflagellates contributed more to bacteria mortality than virus-induced bacterial lysis. By grazing on bacteria, heterotrophic nanoflagellates consumed large quantities of viruses located on the surface and inside bacterial cells. 相似文献
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V.B. Bazarova M.S. Lyashchevskaya T.R. Makarova R.A. Makarevich L.A. Orlova 《Russian Geology and Geophysics》2018,59(11):1410-1418
Overbank deposits in the Komissarovka River valley consist of alternating silt, clay silt, sand, and soils produced by lacustrine, alluvial, and aeolian deposition and by soil formation. Silt and sand layers in the lower part of the section correlate with the events of Early Holocene transgression and Middle Holocene regression of Lake Khanka. Deposition in the lowermost reaches of the Komissarovka River provides a faithful record of local Holocene landscapes controlled by level changes in Lake Khanka. 相似文献
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Makarevich P. R. Larionov V. V. Vodopyanova V. V. Bulavina A. S. Ishkulova T. G. Venger M. P. Pastukhov I. A. Vashchenko A. V. 《Oceanology》2021,61(6):930-943
Oceanology - This paper describes the comprehensive studies of phytoplankton carried out in April 2018 in the northwestern Barents Sea, in the Polar Front region (74.8°–76.2° N), at... 相似文献
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Panichev Aleksander Seryodkin Ivan Popov Vladimir Chekryzhov Igor Makarevich Raisa Lutsenko Tatiana Stolyarova Tatiana Sergievich Aleksander Khoroshikh Pavel Maksimova Darya Petrunenko Yury 《Arabian Journal of Geosciences》2020,13(4):1-11
This paper establishes a mechanical model of the stress distribution in front of the driving face during coal roadway excavation. Theoretical research shows that the stress state in the plastic zone of the driving face is consistent with the limit equilibrium equation, and the elastic zone is in accordance with the equilibrium equation based on elasticity mechanics. Based on this improved mechanical state solution model, different coal material constitutive hypotheses are used for the analysis. The width of the plastic zone calculated under the brittle-perfectly elastic model can reach 2–5 times the height of the roadway, and the stress concentration coefficient can reach two or more times. 3DEC numerical simulation software was used to simulate the stress distribution of the heading face. The results of the simulation are similar to those of the theoretical analysis. Compared with the elastic-perfectly plastic model, the calculated results of the brittle-perfectly elastic model are more consistent with the numerical simulation results. The heading face coal during roadway excavation shows obvious damage, and the strength characteristics of the coal decrease. 相似文献
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P. R. Makarevich 《Oceanology》2008,48(6):813-818
The paper presents the results of studies of seasonal trends in the development of phytoplankton and algae inhabiting one-year ice under the conditions of anomalous hydrometeorological processes that cause freezing of the Kola Bay estuarine zone (Barents Sea). In the years of anomalous ice formation, no changes were observed in the species composition and quantitative characteristics of the plankton algocoenosis, as well as in the time of the phytoplankton vegetation. Meanwhile, it was found that the pelagic community reaches its maximal abundance and biomass later than under normal conditions. The data obtained suggest that, in selected years, the community of ice algae has not enough time to reach its maximal abundance, which is related to the rapid degradation of the ice cover at the beginning of the spring. Therefore, the representatives of the cryoflora proper do not contribute much to the total annual biomass of the phytoplankton of the estuarine pelagic ecosystem of Kola Bay. 相似文献
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G. V. Kovaleva V. V. Povazhnyy A. E. Zolotareva P. R. Makarevich D. G. Matishov 《Oceanology》2014,54(5):618-623
The temporary ice algae community in the mixing zone of brackish and fresh waters of the Taganrog Bay of the Azov Sea is described. A high abundance and biomass of planktonic algae and a high chlorophyll a concentration have been registered in samples of under-ice water taken on February 2013. The mass development of the diatom Stephanodiscus hantzschii Grunow blooming on the ice in the eastern part of Taganrog Bay is described for the first time. The quantitative data on the under-ice microalgae community and the related hydrochemistry are published. The obtained results could be used in total productivity estimates in the Azov Sea. 相似文献
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The taxonomic composition and spatial distribution of pelagic algae were studied in the south-western Kara Sea in August-September 1981. In the north-western and easternmost regions of the study area the phytoplankton community, dominated by neritic diatoms and autotrophic dinoflagellates, was at the late spring bloom stage of the seasonal succession. In the central deep-water zone of the sea, there was a predominance of heterotrophic dinoflagellates from the genera Protoperidinium and Dinophysis , and the autotrophic compartment of the algal community was clearly in a stage of decline. The distribution of the phytoplankton assemblages followed closely the major routes of receding marginal ice zones. Three stages of the seasonal succession were established for the area of interest: (1) early spring (ice edge) bloom of arcto-boreal neritic diatoms; (2) late spring bloom of neritic diatoms and autotrophic dinoflagellates, fuelled by continental run-off; and (3) summer minimum with a predominance of heterotrophic dinoflagellates, followed by autumnal decline of the phytoplankton community. 相似文献
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We present a statistical study of the diurnal variations of the E-region backscatter occurrence observed by 15 SuperDARN radars over 3 years. The diurnal variation of echo occurrence observed by each radar is examined for three levels of geomagnetic activity. It is found that the E-region echo occurrence for individual radars exhibits very similar diurnal variations for low geomagnetic activity, with the differences between radars increasing with activity. This indicates that local processes become more important in the generation of the E-region echoes during disturbed periods. It is also shown that the majority of E-region backscatter structures take the form of diffuse echo bands rather than discrete echo patches, with the dominance of diffuse echoes increasing with activity. Finally, a hypothesis that the echo occurrence is controlled by the radar's coverage of the auroral oval is tested using the electron and ion oval models derived from the DMSP satellite observations. 相似文献