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Original data on the isotope and chemical compositions of mineral springs, cold ground and surface waters, as well as hydrogenic deposits of the Antonovsky manifestation of hydrosulfuric mineral waters (the coast of the Tatar Strait, Sakhalin Island), are presented. The data on the contents of oxygen and hydrogen isotopes in ground and surface waters, as well as the volumetric activity of radon and rare-earth elements are obtained for the first time. Based on automatic monitoring of the physical parameters of the mineral water, its hydrogeological characteristics are determined and balneological properties are assessed. It is found that the mineral waters of the spring are weakly alkaline, hydrocarbonic–chloride calcium–sodium with total dissolved solids (TDS) of up to 1 g/L. According to the isotope data, the genesis of the waters is atmospheric and the circulation time is less than 60 years. The gas composition is dominated by nitrogen of atmospheric genesis (δ15N = 0.0). High contents of organic carbon (Corg = 56.6 mg/L) are explained by the processes of interaction between groundwater and organic matter in water-bearing rocks. When organic matter is decomposed in the presence of sulfates and without access to oxygen, hydrosulfuric acid is released, producing several intermediate and stable sulfur compounds in hydrogenic sediments and bacterial mats. Elemental, sulfide, and sulfate forms of sulfur have been detected in the bottom sediments and in the new formations of the mineral spring, using electron microscopy. The interaction of waters with organic matter of rocks plays a significant role in the formation of the elemental composition of hydrogenic and biogenic deposits of the Antonovsky hydrosulfuric mineral spring and their enrichment with such metals as Zn, Ge, As, Sr, Ba, U, and Th. One characteristic feature of the mineral waters is the presence of a markedly pronounced positive europium anomaly, which is typical of waters with low Eh values.

Original data on the isotopic and chemical composition of mineral waters, cold ground and surface waters, as well as hydrogenic deposits of the Antonovsky manifestation of hydrogen sulfide mineral waters (the coast of the Tatar Strait, Sakhalin Island) are provided in the article. For the first time, data on the content of oxygen and hydrogen isotopes in groundwaters and surface waters, the volumetric activity of radon and the rare-earth elements as well were obtained. Based on automatic monitoring of the physical parameters of the waters, their hydrogeological characteristics were determined and balneological properties were assessed. It has been determined that the mineral waters of the spring are weakly alkaline, hydrocarbonate-chloride calcium-sodium, with TDS of up to 1 g/l. According to isotope data, the genesis of waters is atmospheric, and the circulation time is less than 60 years. The gas composition is dominated by nitrogen of atmospheric genesis (δ15N = 0.0). High contents of organic carbon (Corg. = 56.6 mg/l) are explained by the processes of interaction of groundwaters with organic matter of water-bearing rocks. When organic matter decomposes in the presence of sulfates and without oxygen, hydrogen sulfide is released, giving rise to a number of intermediate and stable sulfur compounds in hydrogenic sediments and bacterial mats. Elemental, sulfide and sulfate forms of sulfur have been determined in the bottom sediments as well as new formations of the mineral spring, using electron microscopy. The interaction of waters with organic matter of rocks plays a significant role in the formation of the elemental composition of hydrogenic and biogenic deposits of the Antonovsky hydrogen sulphide mineral spring and their enrichment with such metals as Zn, Ge, As, Sr, Ba, U, and Th as well. A characteristic feature of mineral waters is the presence of a pronounced positive europium anomaly, which is typical for waters with low Eh values.

The data of 2017, characterizing the modern gas-hydrothermal activity of the Berutarube volcano (Iturup Island, the Southern Kuriles) are presented. It is shown that currently the volcano has intensive solfataric and hydrothermal activity, concentrated within the three main sites near summit part of the edifice. The maximum temperature of steam-gas outlets is 96.6 °C, thermal spring – 80 °C. According to the chemical composition, the hydrotherms of Berutarube volcano are ultra-acid (pH 1.5), mineralized, chloride-sulfate waters with a complex cationic composition.

Since 2002, complex studies of all known thermal springs of Kunashir Island have been carried out. Of the four active volcanoes in the island, three volcanoes have stable hydrothermal systems. In addition to volcanoes, thermal springs in Kunashir are found on the coast and they are associated with tectonic faults. Despite the different morphogenetic types of volcanoes and their activity, the common patterns of zoning of hydrochemical types of thermal waters are typical for volcano-hydrothermal systems. On the periphery of the extrusive domes of the volcanoes, there are solfataric fields with outputs of gases and acid sulfate hydrotherms with temperatures up to 95 °C. Below the slope at a distance from the extrusive domes and solfataric fields an acid chloride-sulfate (sulfate-chloride) sodium hydrotherms with temperatures up to 91 °C are located. At the foot of volcanic edifices, at a considerable distance from the extrusions and outputs of solfataric gases, neutral chloride sodium thermal springs and steams are located. The isotopic composition of oxygen and hydrogen of different hydrochemical types of thermal waters is similar to the isotopic composition of local meteoric waters, which confirms the genesis of hydrotherms due to atmospheric waters with minimal participation of sea and "mantle" waters.

Different types of groundwater manifestations occurring on modern structure of the Baransky volcano were studied. Volcanic and seismic activity influences strongly on hydrology and hydrochemistry of the groundwater of the watershed of Sernaya river. Three types of fluids have been established: volcanic-heated, steam-heated and mature. Existing model of hydrothermal system of Baransky volcano was confirmed using geothermometry and hydrochemical calculations. Thus Baransky volcano is a complex object with atmospheric recharge, deep diorite body as heat source and thick fractured altered andesitic water reservoir, where different types of water springs can emerge.

The dynamics of current retroflection and rings shedding are not yet fully understood. In this paper, the authors develop an analytical model of the Agulhas Current retroflection dynamics using three simple laws: conservation of volume, momentum balance, and Bernoulli’s principle. This study shows that, for a retroflecting current with a small Rossby number, this theoretical model is in good agreement with numerical simulations of a reduced-gravity isopycnal model. Otherwise, the retroflection position becomes unstable and quickly propagates upstream, leaving a chain of eddies in its path. On the basis of these findings, the authors hypothesize that the westward protrusion of the Agulhas retroflection and the local “zonalization” of the Agulhas Current after it passes the Agulhas Bank are stable only for small Rossby numbers. Otherwise, the retroflection shifts toward the eastern slope of the Agulhas Bank, where its position stabilizes due to the slanted configuration of the slope. This study shows that this scenario is in good agreement with several high-resolution numerical models.

The paper presents the results of a comprehensive analysis of GPR data and geophysical well survey data (gamma-ray logging and self-polarization potentials) to study the 3-D spatial structure of the Daginsky hydrothermal system discharging zone (Sakhalin Island) and its hydrogeological situation. According to the GPR method, the paleo-valleys were identified, the morphology of which indicates the presence of runoff hollows, the accumulation of sandy-aleurite-clay sediments covered with peat formations. It can be concluded that the caprock in this area consists of a pack of water layers and permeable zones. Based on the data of geophysical studies in wells, three zones can be distinguished, each of which is characterized by the corresponding values of gamma activity and changes in the potentials of its own polarization. All this helps in identifying permeable thermally conductive zones. The data obtained are of practical importance.

The article presents the results of researches of thermal waters of South-Eastern solfataric field of Ushishir volcano (Yankicha Island, Central Kurile Islands) in 2007 and 2015. Detailed studies of the physicochemical properties of the hydrothermal springs of the volcano were begun in 1950-60 years. Modern studies have confirmed the stability of physical and chemical parameters of hydrotherms. Modern thermal waters (temperature up to 100 °C), as before, can be attributed to acidic (pH 2.8-3.6), highly mineralized (TDS 23-36 g/l), sodium chloride. The chemical composition and ratio of the main macroelements of hydrotherms are close to the sea waters of the region. The uniqueness of these waters distinguishing them from other coastal hydrotherms of the Kuril Islands is their high acidity. The increased content of balneological elements (Br – 107 mg/l; B – 36 mg/l; I – 0.5 mg/l) in hydrotherms determines their high therapeutic value, which allows them to be used in the treatment and prevention of a wide range of diseases.

The Vitoria Eddy (VE) is a cyclone in the Brazil Current (BC) formed immediately to the south of the Vitoria–Trindade Ridge. Using altimetric derived SSH and outputs of a regional ocean model, we show evidences that once the VE is shed from a BC meander, if it is not reabsorbed, it follows a northward path crossing the Vitoria–Trindade Ridge. In all observed events of equatorward translation, the VE interacts with the anticyclonic Abrolhos Eddy (AE) centered about 19°S–37°W. Depending on the strength of the AE, the VE can take one of two different paths: one orbiting the AE and the other tight to the bathymetric lines. During the entire translation, the AE is under the influence of the equatorward intermediate flow of the Intermediate Western Boundary Current/North Brazil Undercurrent system, a key factor for its equatorward translation.

We studied the movements of polypropylene markers in a composite vortex as a model for the transport of garbage in the ocean in the laboratory setting. We showed that when in motion a marker rotates around the center, as well as around its own axis. We determined the dependence of the angular velocities of marker rotation on the distance to the center of a vortex, whose values depend on the size of the markers at fixed permanent conditions. We found the separatrix that divides the areas of the initial positions, from which the marker is displaced upon further movement to the center of the vortex or to the container walls.

Both the North Brazil Current (NBC) and the Brazil Current (BC) are western boundary currents (WBCs) that separate from the western Atlantic coast. The NBC retroflects and sheds several rings per year (at the retroflection region), whereas the BC rarely sheds rings near its separation point. Traditionally, the difference between these two WBCs has been attributed to the Malvinas Current (MC), whose momentum flux opposes the poleward momentum flux of the BC, thus preventing rings shedding at the point where the current leaves the coast. Even in the absence of the MC, rings from the separating BC would have never been regularly generated because of the relatively large slant of the coastline relative to the zonal direction. Using the recently proposed theory of Zharkov and Nof, it is demonstrated that the large inclination of the coastline between 20° and 45°S (approximately 50°) lies within the regime that does not allow the BC a continuous shedding of rings. In contrast, the inclination of the coastline between 5° and 8°N is sufficiently small to allow the NBC a continuous and smooth shedding of rings. The importance of the coastline inclination comes about through a ring β-induced westward propagation rate. In the small inclination case, the alongshore migration is fast, allowing the newly formed rings to quickly escape from their generation zone (i.e., before they are recaptured by the newly born rings generated behind). In contrast, in the high inclination case, the alongshore speed is so small that the rings spend a long time in the generation area and, consequently, are usually recaptured by the new rings generated just behind them. The authors argue, paradoxically, that the rings occasionally shed by the BC are probably due to the MC that advects the rings away from the generation area, preventing their recapture by the current behind them. Although no new analytical solutions are presented, the authors elaborate on the application of the recapturing condition to the NBC and BC and show new numerical simulations for both the NBC and the BC.

Recent proxies analysis suggest that, at the end of the last glacial, there was a significant increase in the injection of Agulhas rings into the South Atlantic (SA). This brought about a dramatic increase in the salt-influx (from the Indian Ocean) into the SA helping re-start the then-collapsed meridional overturning cell (MOC), leading to the termination of the Younger Dryas (YD). Here, we propose a mechanism through which large variations in ring production take place. Using nonlinear analytical solutions for eddy shedding we show that there are restricted possibilities for ring detachment when the coast is oriented in the north-south direction. We define a critical coastline angle below which there is rings shedding and above which there is almost no shedding. In the case of the Agulhas region, the particular shape of the African continent implies that rings can be produced only when the retroflection occurs beyond a specific latitude where the angle is critical. During glaciation, the wind stress curl (WSC) vanished at a latitude lower than that of the critical angle, which prohibited the retroflection from producing rings. When the latitude at which the WSC vanishes migrated poleward towards its present day position, the corresponding coastline angle decreased below the critical angle and allowed for a vigorous production of rings. Simple process-oriented numerical simulations (using the Bleck and Boudra model) are in very good agreement with our results and enable us to affirm that, during the glacials, the behavior of the Agulhas Current (AC) was similar to that of the modern East Australian Current (EAC), for which the coastline slant is supercritical.

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.

We study the dependence of the hydrodynamic pressure induced in a liquid as a result of motion of a load of constant intensity over the floating ice cover on the flexural stiffness of ice and the character of distribution of the load over the moving region. The contribution of the deflection of ice in the vicinity of the load and the induced flexural and flexural-gravitational waves to the formation of the field of hydrodynamic pressure near the ice-water interface is estimated.

The influence of drifting broken ice on the propagation of small-amplitude plane surface waves from an infinitely deep region of a basin to a region of finite depth over a bottom shelf is analyzed on the basis of wave source theory. The variations in the characteristics of the reflected and transmitted waves and the fluid surface perturbation profile due to the drifting ice are estimated as functions of the distance from the shelf.

Ship waves generated in an exponentially stratified fluid when an axisymmetrical area of pressure of constant intensity moves over a floating ice cover are studied in a linear statement. The influence of ice rigidity on the distribution of amplitudes of the internal wave disturbances along the constant phase lines is analysed.

Ice cover oscillations induced by a moving load are studied in a linear formulation using a threedimensional flexural-gravity wave model. Theoretically-derived ice deflection profiles and critical velocities of the moving vehicle are compared with known experimental data.

Color ratio images created from multispectral observations of Phobos are analyzed in order to characterize the spectral properties of Phobos' surface, to assess their spatial distributions and relationships with geologic features, and to compare Phobos' surface materials with possible meteorite analogs. Data calibration and processing is briefly discussed, and the observed spectral properties of Phobos and their lateral variations are examined. Attention is then given to the color properties of different types of impact craters, the origin of lateral variations in surface color, the relation between the spatial distribution of color properties and independently identifiable geologic features, and the relevance of color variation spatial distribution to the origin of the grooves.