Transformation of suspended particulate matter into sediment in the Kara Sea in September of 2011     

A. Yu. Lein  P. N. Makkaveev  A. S. Savvichev  M. D. Kravchishina  N. A. Belyaev  O. M. Dara  M. S. Ponyaev  E. E. Zakharova  A. G. Rozanov  M. V. Ivanov  M. V. Flint 《Oceanology》2013,53(5):570-606

The biogeochemical processes participating in the transformation of the particulate matter into sediment along the Yenisei River-St. Anna Trough (Kara Sea) meridional profile were studied using hydrochemical, geochemical, microbiological, radioisotope, and isotope methods. The water-sediment contact zone consists of three subzones: the suprabottom water, the fluffy layer, and the surface sediment. The total number, biomass, and integral activity of the microorganisms (dark ¹⁴CO₂ assimilation) in the fluffy layer are usually higher than in the suprabottom water and sediment. The fluffy layer shows a decrease in the oxygen content and the growth of the dissolved biogenic elements. It was provided by the particulate organic matter supporting the vital activity of the heterotrophs from the overlying water column and by the flux of reduced compounds (NH₄, H₂S, CH₄, Fe²⁺, Mn²⁺, and others) from the underlying sediments. The C_org isotopic composition of the fluffy layer and the sediments is 2–4 ‰ heavier than that of the particulate matter and sediment due to the presence of the isotopically heavy biomass of microorganisms. A change in the isotopic composition of the C_org in the fluffy layer and surface sediment as compared to the C_org of the particulate matter is a widespread phenomenon in the Arctic shelf seas and proves the leading role of microorganisms in the transformation of the particulate matter into sediment.  相似文献   

Field experiment on studying solar radiation passing through aerosol layers     

Yu. A. Izrael  V. M. Zakharov  N. N. Petrov  A. G. Ryaboshapko  V. N. Ivanov  A. V. Savchenko  Yu. V. Andreev  Yu. A. Puzov  B. G. Danelyan  V. P. Kulyapin 《Russian Meteorology and Hydrology》2009,34(5):265-273

Results of a field experiment on studying solar radiation passing in the visible wavelength range are described with the model aerosol media created in the surface atmosphere. High-efficiency thermocondensation generators were used for creating model aerosol media. The index of refraction and an average size of the aerosol particles formed are close to those characteristic of the natural stratospheric aerosol. The composition and technical characteristics of the equipment complex used in the experiments to control aerosol optical and microphysical parameters and meteorological conditions of the experiment are considered. The Gaussian model of impurity dispersion in the boundary layer is used for the analysis and interpretation of measurement results. It is found that with a number concentration of aerosol particles of ～10²–10³ cm^?3 (which corresponds to the aerosol density in the deposited layer of about 1–10 mg/m² with the layer thickness along the ray path of about 100 m) the solar radiation attenuation with artificial aerosol layers accounts for 1 to 10%. Model estimates are in satisfactory agreement with the measurement results.  相似文献   

Paleolithic hunting in a southern Moravian landscape: The case of Milovice IV,Czech Republic     

Ji&#x;í Svoboda  Zbigniew M. Boche&#x;nski  Vra ulíkov  Alena Dohnalov  Srka Hladilov  Martin Hloek  Ivan Hor ek  Martin Ivanov  Miroslav Krlík  Martin Novk  Alexander J.E. Pryor  Sandra Szelov  Rhiannon E. Stevens  Jaros&#x;aw Wilczy&#x;nski  Piotr Wojtal 《Geoarchaeology》2011,26(6):838-866

The Dolní Věstonice–Pavlov–Milovice area (Czech Republic) on the slopes of the Pavlov Hills provides an opportunity for correlating the geomorphology of the Dyje River valley with Gravettian settlement patterns. Although the sites vary in size and complexity, they create a regular chain of strategic locations at elevations between 200 m and 240 m asl. In 2009, a road collapsed into deserted cellars inside the village of Milovice and revealed a complex of archaeological layers deep within loess, at an elevation of only 175 m asl. This paper presents an analysis of this atypical archaeological site location and compares the results with the other sites. We argue that this location allowed direct contact with mammoth herds concentrated on the floodplain, while the aquatic environment offered possibilities for gathering plants and fishing. This site represents a new aspect of organized settlement, hunting strategies, and short‐distance human movements during the Gravettian within this area. © 2011 Wiley Periodicals, Inc.  相似文献   

Milne's problem in the theory of spectral line formation     

V. V. Ivanov 《Astrophysics》1968,4(1):1-3

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On the spiral structure of M33     

G. R. Ivanov  P. Z. Kunchev 《Astrophysics and Space Science》1985,116(2):341-348

The spiral structure of M33 has been examined on the basis of 197 associations. The parameters of the orientation of the plane are derived. It is supposed to be a system consisting of seven logarithmic spirals. Two principal arms have been interpreted through the use of the density-wave theory. The remaining multiple arm features of M33 may be explained with the stochastic self-propagating model. The distribution of surface brightness segments speaks for the existence of different mechanisms of star formation in M33.  相似文献   

Assessment aspect of contamination of the Arctic estuary ecosystems     

Vladyslav V. Khlebovich  Vladimir V. Ivanov  Vyacheslav M. Makeyev 《Marine pollution bulletin》1997,35(7-12):222-225

Estuarine ecosystem may be considered as ‘pulse-targets’ where information about contamination of all-river basin and about scale and forms of contaminants input to the seas is concentrated. The nucleus of the estuarine processes of contaminants transformation and sedimentation is the critical salinity zone. In the real natural conditions of the Arctic the salinity dependent processes are masked by hydrodynamic effect. The tasks of effective chemical and biological monitoring of Russian Arctic estuarine ecosystems are formulated.  相似文献   

Macrobenthic communities of the Pechora Sea: the past and the present on the threshhold of the prirazlomnoye oil-field exploitation     

V. B. Pogrebov  G. I. Ivanov  N. N. Nekrasova 《Marine pollution bulletin》1997,35(7-12):287-295

On data of bottom sampling, carried out by means of grab, trawl and underwater photography in August–September of 1993 in the area of the Pechora Sea, quantitative regularities of macrobenthos distribution are described for the ecological monitoring purposes. Maps of -biodiversity and biomass indices, bottom communities and trophic zones, singled out by dominant method, are presented. Assessment of structure changes of the investigated area bottom communities during the last 60–70 years is fulfilled. It is shown that the described communities on the whole are of natural undisturbed character and that the revealed changes are within the natural fluctuations in the abundance of benthic populations or may be interpreted in terms of methodical differences in the data analysis and generalization by different authors.  相似文献   

Interannual variability in water masses in the Greenland Sea and adjacent areas   总被引：1，自引：0，他引：1  

Genrich V. Alekseev  Ola M. Johannessen  Alexander A. Korablev  Vladimir V. Ivanov  Dmitry V. Kovalevsky 《Polar research》2001,20(2):201-208

Oceanographic data covering the period 1950–1998 are used to determine interannual variations in the convection intensity and water mass structure in the Greenland Sea and adjacent areas. Extremely cold winters throughout 1965–1970 assisted intensification of the water vertical exchange in the Greenland and Norwegian seas. As a result, cold and fresh Greenland Sea Deep Water (GSDW) production was extremely high in the central Greenland Sea while in the southern Norwegian Sea warm and salty water spread downwards. The recent rapid warming in the Greenland Sea Gyre interior from 1980 originates, we argue, from an increase in the Atlantic Water (AW) temperature due to the advection of warm waters into the region with the Return Atlantic Current. The negative water temperature and salinity trends in the upper 300 m layer of the Atlantic Water in the Norwegian Sea prevailed during 1950–1990, whereas during 1980–1990 the water temperature trends are indicative of warming of that layer. Observation series obtained onboard the Ocean Weather Ship Mike confirmed the existence of layers with advectiondriven high oxygen concentrations in intermediate and deep layers. The depth of oxygen maxima and the values of oceanographic parameters at this horizon can be regarded as indicators of the convection intensity in the Arctic domain. A simultaneous rise in NAO index and GSDW temperature points to a link between atmospheric and thermohaline circulation. Weakening in water exchange with the North Atlantic could be the reason for the Polar Water recirculation increase within the Nordic seas.  相似文献   

The brightest blue stars in M33 galaxy as unresolved star groups     

V. K. Golev  G. R. Ivanov  P. Z. Kunchev 《Astrophysics and Space Science》1987,135(2):301-306

The brightest blue stars in the M33 galaxy have peculiar images. A method to resolve them into components was applied. The brightest members stars atV15–16 mag were recognized as multiple ones. Some stars up toV=17 mag have multiple structures, too. The image of the brightest blue stars consist of two or more components and probably some of them, in fact, resemble dense stellar groups such of R 136 in 30 Dor.  相似文献   

A new 75-day cepheid in M31     

G. R. Ivanov 《Astrophysics and Space Science》1985,115(2):409-411

The light curve of the variable with a period of 75^d and amplitude of the lightA _B0 ^m .5 were obtained. It was assumed that the variable was a cepheid. Having in mind the absence of cepheids withP>50^d in M31 it is possible that the new variable is a cepheid-like variable similar to V810 Cen.  相似文献