Investigation of Transformations of the Local Regions of Pollution in the Northwest Part of the Black Sea Caused by the Motion of a Cyclone

By the method of mathematical simulation, we study the evolution of local discharges of pollutants on the northwest shelf of the Black Sea induced by the motion of a cyclone. We use the nonlinear equations of motion of a homogeneous viscous fluid in the hydrostatic approximation and the equation of turbulent diffusion. A cyclonic formation is represented by a moving axisymmetric area of low pressures. The discharges of pollutants are caused by the action of instantaneous sources located on the sea surface. We perform the analysis of dependences of the paths of motion of polluted regions, the periods of their dissipation, and the depths of penetration of pollutants on the bottom topography and the intensity of diffusion processes. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 17–27, November–December, 2005.     

Generation of seiches by moving baric formations

We consider a plane problem of generation of barotropic seiches in the case of motion of a region of disturbances of atmospheric pressure over a bounded basin. The nonlinear system of equations of long waves with regard for the quadratic dependence of bottom friction is solved by the finite-difference method. The calculations are carried out for three basins of variable depth corresponding to rectangular sections of the Black Sea and Sea of Azov. It is shown that the passage of the baric anomaly over the basin is accompanied by the generation of the lowest seiches. The oscillations of fluid are especially intense in the shallow-water zones of the basins. Seiches exhibit a trend to intensification as the velocity of motion of the atmospheric disturbance increases. The dependence on the width of the baric anomaly is not monotonic. In the shelf zone, the amplitude of oscillations of the level can be several times higher that the pure hydrostatic response of the sea surface. In the analyzed basins, the influence of nonlinearity on the seiches is weak. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–15, November–December, 2007.     

Transformation of the ocean level under a moving area of disturbances of atmospheric pressure

Within the framework of the linear model of long waves, we study the transformations of the ocean surface under the conditions of uniform motion of a zone of disturbances of atmospheric pressure. The analysis is based on the evaluation of a two-dimensional integral appearing in the exact expression for the shape of the free surface of the ocean. It is shown that Earth’s rotation, the increase in the horizontal scale of the atmospheric anomaly, and the decrease in the depth of the basin make the displacements of the sea level smaller than those predicted by the law of inverted barometer. The motion of the baric anomalies leads to the opposite effect. In the open ocean, the displacements of its surface under a moving front are more pronounced than in the case of a moving circular anomaly of atmospheric pressure. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 3–14, March–April, 2007.     

Statistical characteristics of cyclones and anticyclones over the Black Sea in the second half of the 20th century

By using the NCEP reanalysis data for 1952–2000, we estimate the parameters of cyclones and anticyclones in the Black-Sea region and evaluate the statistical characteristics of their variability for each season. It is shown that the frequency of cyclones decreases in all seasons (except summer) as a result of the intensification of the North Atlantic Oscillation in the 1960–90s and the displacement of the predominant paths of synoptic disturbances to the north. For anticyclones, we reveal the opposite trend. The parameters of cyclones and anticyclones are characterized by quasiperiodic variations on the subdecadal scale also induced by the North Atlantic Oscillation. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 47–58, November–December, 2007.     

A review of three transform margins off eastern Canada

 The southwest Newfoundland transform margin has been studied by deep seismic reflection and refraction. Lower crustal reflectivity strengthens towards the margin, where there is a shear zone of thinned continental crust overplated with oceanic material. The reflectivity may be due to shear fabrics in the crust. Crustal thinning probably took place by flow in the lower crust. The Ungava transform margin has been less studied but has been explored and drilled. It appears more volcanic in character. The north Baffin region has undergone a complex tectonic history and provides an example of the transition from continent–ocean to continent–continent transform motion. Received: 9 March 1995 / Revision received: 25 July 1995     

The hydrostatic motor: Utilization of hydrostatic pressure differentials in the deep sea

A hydrostatic motor that converts hydrostatic pressure gradients in the deep sea into harnessable mechanical energy has been developed and successfully tested. Controlled equalization between higher ambient hydrostatic pressures at oceanic depths and lower pressures retained from atmospheric or sea-level conditions—sealed within a chamber as part of the motor assembly—produces reciprocating motion of a piston. This motion is utilized for power or work requirements. Our needs have been directed toward oceanographic instrumentation requirements but many other applications are likely.     

Capillary-Gravitational Waves of Finite Amplitude on the Surface of a Homogeneous Liquid

The method of multiple scales is used to deduce equations for three nonlinear approximations of the capillary-gravitational disturbances of the free surface of a layer of a homogeneous liquid of constant depth. In these equations, the space-time variations of the wave profile in the expression for the velocity potential on the liquid surface are taken into account. On this basis, we construct asymptotic expansions up to the quantities of the third order of smallness for the velocity potential and elevations of the liquid surface induced by running periodic waves of finite amplitude. Furthermore, we analyze the dependences of the amplitude-phase characteristics of wave disturbances on the surface tension, depth of the liquid, and the length and steepness of waves of the first harmonic. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 25–34, September–October, 2005.     

Distribution of Flexural Strains in a Sea-Ice Cover Caused by the Uniform Motion of an Area of Constant Pressure

The space distribution of flexural strains induced in a floating ice cover by its oscillations caused by the motion of an area of constant pressure is investigated. The dependences of flexural strains in front the load, in the loaded area, and in the wave track on the thickness of ice, velocity of propagation of pressure, and the type of its distribution are analyzed. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–16, November–December, 2005.     

Vertical structure of the field of current velocities in the northwest part of the Black Sea based on the <Emphasis Type="Italic">LADCP</Emphasis> data for May 2004

The profiles of absolute current velocity obtained by using a lowered acoustic doppler current profiler (LADCP) are presented. In the course of the BSERP-3 expedition, the measurements were carried out in the regions of the Rim Current, anticyclonic eddy, and northwest shelf. In the core of the Rim Current, a unidirectional motion of waters is traced in layers below the main pycnocline down to depths greater than 500 m. Its characteristic velocity can be as high as 0.08 m/sec. It is shown that the direct action of the eddy is detected in the shelf region at distances larger than 20 km from the outer edge of the shelf in the zone bounded by an isobath of 100 m. The formation of multilayer vertical structures in the field of current velocities is revealed in the region of interaction of the anticyclonic eddy with irregularities of the bottom on the side of the shelf. A two-layer structure of currents with specific features in the layer of formed seasonal pycnocline is observed in the region of the shelf down to an isobath of 100 m. The profiles of the moduli of vertical shears of currents averaged over the casts ensemble are presented for the abyssal and shelf parts of the sea. It is shown that the shears induced by the geostrophic currents and wave processes in the region of the main pycnocline are comparable. Below the pycnocline, the shears are mainly determined by the wave processes. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 25–37, November–December, 2008.     

East-west distribution of POC fluxes estimated from <Superscript>234</Superscript>Th in the northern North Pacific in autumn

Observations of primary productivity, ²³⁴Th, and particulate organic carbon (POC) were made from west to east across the northern North Pacific Ocean (from station K2 to Ocean Station Papa) during September–October 2005. Primary productivities in this region varied longitudinally from approximately 236 to 444 mgC m⁻²d⁻¹ and clearly indicate the West High East Low (WHEL) trend. We estimated east-west variations in the POC flux from the surface layer (0–100 m) by using ²³⁴Th as a tracer. POC fluxes in the western region (44–53 mgC m⁻²d⁻¹) were higher than those in the eastern region (21–34 mgC m⁻²d⁻¹). However, the export ratios (e-ratios) ranged from approximately 8% to 16% and did not show the WHEL trend. Contrary to our expectation, no relation between POC flux (or e-ratio) and diatom biomass (or dominance) was apparent in autumn in the northern North Pacific.     

Influence of the Space Distribution of Atmospheric Pressure on the Structure of Free Wave Surface in a Basin of Variable Depth

Within the framework of the linear theory of long waves, we study forced oscillation of liquid in a ring basin of variable depth by using numerical methods. As a generator of waves, we use periodic (in time) variations of atmospheric pressure. The action of the Coriolis force is taken into account. The liquid is regarded as homogeneous and inviscid. We analyze the dependences of the structure of the free wave surface (the number and location of nodal lines) on the period and space distribution of disturbing pressures. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 11–23, March–April, 2005.     

Analysis of the Black-Sea climatic fields below the main pycnocline obtained on the basis of assimilation of the archival data on temperature and salinity in the numerical hydrodynamic model

We study model climatic temperature and salinity fields and the fields of currents in the 350–1000-m layer. The following specific features are revealed: Colder waters are observed in the regions with anticyclonic vorticity. At the same time, warmer waters are detected in the regions with cyclonic vorticity. This temperature effect can be explained by the elevation of temperature with depth below the main pycnocline. In the region of the Sevastopol anticyclone, at depths greater than 500 m, we observe a zone of cyclonic rotation of waters. Near the Caucasian coast, in the region of Gelendzhik, we reveal a narrow jet current existing at a depth of 350 m from March till July. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp.3–15, January–February, 2009.     

Balance of Volume Transports between Horizontal Circulation and Meridional Overturn in the North Pacific Subarctic Region

Horizontal and meridional volume transports on timescales from intra-seasonal to interannual in the North Pacific subarctic region were investigated using a reanalysis dataset for 1993–2001 that was constructed from an assimilation of the TOPEX altimeter and in situ data into an eddy-permitting North Pacific ocean general circulation model. The barotropic flow is excited along east of the Emperor Seamounts by the western intensification dynamics. The volume transport of this flow compensates for that across the interior region east of the Seamounts below the summit depth of the Seamounts. The Oyashio, which is also considered as a compensation flow for the transport in the whole interior region, includes baroclinic as well as barotropic components. Baroclinic transports in the whole interior region exceed those in the western boundary region in the upper (200–1000 m) and lower (2000–5000 m) layers, and the total transport is northward (southward) in the upper (lower) layer. These excesses of the baroclinic transport are balanced by a vertical transport of the meridional overturn. The meridional overturn has a complementary relation to the basin-scale baroclinic circulation in the North Pacific subactic region. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dynamic modes of propagation and transformation of subsurface gravitational lenses

We study the dynamic features of propagation of subsurface gravitational lenses and the conditions of changes in the modes of control over their motion by various internal and external forces. As these forces, we study the action of drag, molecular and turbulent viscosity due to the presence of internal and external forces, and deceleration caused by the effects of double diffusion. We also analyze the modes of propagation of small-scale gravitational lenses. The information about these lenses taken from the literature is supplemented and generalized. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–14, May–June, 2006.     

Modeling of the breeze circulation of waters in the Kerch Strait

The problem of the numerical analysis of currents in the Kerch Strait is studied within the framework of a linear nonstationary two-dimensional model in the nondivergent approximation. We describe the actual situation when the motion is induced by a breeze against the background of the daily average northeast wind. The breeze is specified as acting in a narrow coastal strip and can be classified as a zonal wind. The variations of circulation near the Tuzla Island are studied in detail. It is shown that the contribution of the breeze circulation to the total circulation can be significant for the explanation of the processes running in the Kerch Strait. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 16–27, November–December, 2007.     

Accumulation and Export of Dissolved Organic Carbon in Surface Waters of Subtropical and Tropical Pacific Ocean

Dissolved organic carbon (DOC) concentrations in surface waters of the Pacific Ocean during October–November, 1995, were determined using a high-temperature combustion method. The DOC in the surface mixed-layer was approximately homogeneous with a concentration between 55 and 89 μmol C l⁻¹. This homogeneity indicates that there is a strong control of the vertical distribution of DOC by mixing processes. The DOC concentrations in the mixed-layer in the subtropical region were up to 27 μmol C l⁻¹ higher than in the tropical region. This difference reflects the subtropical accumulation and the tropical export of DOC. There is a significant positive correlation between DOC and chlorophyll a concentrations in the mixed-layer of the North Pacific subtropical region, suggesting that phytoplankton is the primary source of DOC accumulated in this region. Calculations using simple box models suggest that DOC export in the tropical region (0–50 m depth, 10°N-10°S, along 160°W) occurs primarily by poleward advection at a rate of 0.5–3 mmol C m⁻²day⁻¹. A comparison with estimates of the export rate of particulate organic carbon published in previous studies leads us to conclude that DOC export may contribute less to the carbon budget in the tropical region than has recently been supposed. This revised version was published online in August 2006 with corrections to the Cover Date.     

A Compilation of Geophysical Data from the Lazarev Sea and the Riiser-Larsen Sea, Antarctica

On the basis of new geophysical data acquired by the Federal Institute of Geosciences and Natural Resources (BGR) and the Polar Marine Geological Research Expedition (PMGRE) as well as existing data new geophysical maps were compiled for the Lazarev Sea and the Riiser-Larsen Sea between 10°W and 25°E. The new results are: – The drastic change in the strike direction of the volcanic Explora Wedge between longitudes 10°W and 5°W is accompanied with a gradual change from one major wedge, i.e. the Explora Wedge, into at least two wedge-shaped volcanic constructions, each manifested by a sequence of seaward-dipping reflectors in the seismic records. – The southern Lazarev Sea is best described as a continental margin affected by multiple rifting episodes accompanied with transient volcanism. – A distinct N80°E striking basement depression separates the volcanic-prone continental margin of the southern Lazarev Sea from oceanic crust upon which the Maud Rise rests. The southern scarp of the narrow depression was presumably aligned with the eastern scarp of the Mozambique Ridge during the Early Cretaceous. – The Astrid Ridge proper occupies the transition from the volcanic-prone continental margin of the Lazarev Sea to old oceanic crust of the Riiser -Larsen Sea, and it rests upon a large volcanic apron which covers the basement of the southwestern Riiser-Larsen Sea. – No evidence was found that prolific volcanism has affected the early opening of the Riiser-Larsen Sea. – The Lazarev Sea is a sediment-starved region.     

瘦尾胸刺水蚤适应近岸多变环境的灵活摄食策略

Centropages tenuiremis is a species with a wide distribution range in disturbed coastal waters.However,due to a lack of dietary information,it remains unclear as to how they maintain such dominance in fluctuating conditions.In this study,C.tenuiremis was collected from the Daya Bay Nuclear Power Plant both in inlet and outfall regions at 06:00,12:00 and 18:00 on April 27,2011 and their in situ diet was analyzed using a PCR protocol targeting 18S ribosomal genes.Thirty-four species of prey organisms were identified totally,including Dinophyta,Baciliariophyta,Viridiplantae,Rhizaria,Apicomplexa,Chordata,Mollusca,Arthropoda and Fungi,indicating an obvious omnivorous feeding habit of C.tenuiremis.Centropages tenuiremis obviously exhibited spatial and temporal variations in diet composition.More plant prey(land plants and phytoplankton)were consumed in the morning(~50%),while more animal prey(metazoans and protozoans)were ingested at midday and night(60%–70%).Furthermore,a more diverse diet was detected in the outfall region(10–11 taxa),where the temperatures were relatively higher and more fluctuating,than in the control region(5–10 taxa).This finding indicated that C.tenuiremis could potentially expand its food spectrum under stressful condition.Specifically,C.tenuiremis exhibited phytoplankton preference(58.62%–67.64%)in the outfall region with a lower omnivory index(0.27–0.35)than in the control region(0.51–0.95).However,phytoplankton density was lower than that in the control region,suggesting a possible herbivorous tendency of C.tenuiremis under elevated temperatures to balance the energy acquirement and feeding effort.The flexible food choices of C.tenuiremis observed here could effectively buffer environmental fluctuations and might be an important survival strategy in coastal ecosystems.