The relationship between the behavioral activity and the underwater vocalization of the beluga whale (<Emphasis Type="Italic">Delphinapterus leucas</Emphasis>)

The underwater vocalizations of the beluga whale summering in Onega Bay (64°24′N, 35°49′E) were recorded in June–July of 2008. The vocalizations were classified into five major whistle types, four types of pulsed tones, click series, and noise vocalizations. To determine the relationship between the behavioral activity and the underwater vocalizations, a total of fifty-one 2 minute-long samples of the audio records were analyzed in the next six behavioral contexts: directional movements, quiet swimming, resting, social interactions, individual hunting behavior, and the exploration of hydrophones by beluga whales. The overall vocalization rate and the percentage of the main types of signals depend on the behavior of the belugas. We suggest that one of the whistle types (the “stereotype whistle”) is used by belugas for long-distance communications, while other whistle types (with the exception of “squeaks”) and three types of pulsed tones (with the exception of “vowels”) are used for short distance communication. The percentage of “squeaks” and “vowels” was equally high in all the behavioral situations. Thus, we assume that “squeaks” are contact signals. “Vowels” have a specific physical structure and probably play a role in identification signals. A high rate of the click series was observed in the process of social interactions.     

Upwelling age: an indicator of local tendency for coastal upwelling

A proxy named “upwelling age”, defined as the ratio of wind time scale to “advection time”, was developed to quantify the local tendency for coastal upwelling. The formulation of the “advection time” was derived from Ekman theory. A 3D numerical model was used to validate and refine the theoretical formula by simulating a total of 30 cases of different bottom topographies and wind stresses. The results agree reasonably well with the theoretical formulation although some modifications are necessary. The final formulation of the “advection time” was parameterized as a function of pycnocline depth, bottom slope, and wind stress.     

The Deep-Sea Fan deposits of the miocene Marnoso-arenacea formation, northern Apennines

Submarine fans of different sizes, geometry, and petrology were built in the Marnoso-arenacea Basin, a migrating foredeep within an active continental margin. In an initial depositional stage, a well-developed basin plain received sediment from flows that by-passed restricted fan systems, now buried, located near the north end of an elongated basin. Minor fans grew near the steeper, tectonically deformed side of the basin. In the later stage, turbidite deposition was stopped in the former basin plain. Sediment sources and feeder channels shifted and fed fan lobes that prograded in a narrower trough and were distored (choked). The tectonic control on development of megasequence and sand bodies is stressed here in contrast with previous emphasis on “inner” or “autocyclic” mechanisms. Margin setting represents fan and/or source area     

Seistec Seismic Profiles: A Tool to Differentiate Gas Signatures

The presence of gas is a common feature in many seismic sections. However, the origin of the gas is often difficult to determine. Recently acquired very high resolution seismic profiles using an IKB Seistec boomer provide useful insight to the understanding of the gas origins in a range of environmental settings including sea lochs and coastal lagoons. The gas features are described both from a qualitative point of view through their acoustic facies, and quantitatively through the associated seismic signal (polarisation, amplitude). Acoustic facies include acoustic turbidity, gas “curtains” and “blankets” as well as “white fringes” and “black shadows”. All the features encountered have been related to specific gas nature generated by different sources (organic matter degradation in paleo-valley infillings, waste material effluent).     

Hydrochemical conditions of the “Chistaya Banka” polygon in the Volga’s avant delta

Characteristics of different types of river drainage were obtained during studies of a polygon in the near-mouth part of the Volga River in 2000–2003: “fast” (flowing through deep channels) and “slow” (that which passes through the littoral parts of the delta (1–2 m)). The low current velocities (lower than in the channel waters by a factor of ten), the abundance of water vegetation, and the strong heating of the waters lead to the high intensity of the biochemical processes. Therefore, the chemical composition of the waters is subjected to significant transformation with intensity so high that it allows comparing these regions with some sort of “bioreactor.” These changes influence the dissolved oxygen and various forms of carbon content.     

Large-scale slumps off southern India and Sri Lanka

Two suites of slumps from opposite margins of the Gulf of Mannar, between Sri Lanka and southern India, have met and coalesced. The “Eastern Comorin” Slump is the more coherent of the two with a length of 70 to 100 km. The “Colombo” side slump consists of two to four blocks 15 to 35 km in length. Both slump-suites decrease to the south. A paleoslump underlies the western toe of the East Comorin Slump at a depth of some 800 meters. To the south, an enlarging and deepening submarine canyon marks the area of slump coalescence.     

On the wind conditions of a shallow as a factor of the formation of satellite images of the Sea (Using the example of the South Caspian Sea)

Based on the scatterometer QuickScat wind data and the water-leaving radiances from the ocean color scanner SeaWiFS data for 2000–2004, we composed a pair of mean annual images of a testing site in the South Caspian Sea under conditions of west-bound and east-bound winds corresponding to the offset and onset state of the shallows in the east of the testing site. It was established that both the “offset” and “onset” radiances grow shorewards, but the former becomes about twice as large as the latter in the middle of the shallows with 10–15 m of water, while their difference tends to zero at the seaward and coastal boundaries of the shallow. These and other findings are hypothetically attributable to the inclination of the sea floor of the shallows, due to which the surfacing of bottom sediments resuspended by the drift current takes less time under the “offset” wind conditions than under the “onset” ones. The study’s results indicate that the effect of the bottom sediments resuspension upon the structure of the images of the marine shallows is universal in character and needs to be taken into account to improve the bio-optical algorithms for estimating the admixtures in the thickness of the shallows from the satellite data.     

“Sigma-1” Measuring Complex for the Investigation of Small-Scale Characteristics of Hydrophysical Fields in the Upper Layer of the Sea

We describe a new measuring complex aimed at the investigation of small-scale processes in the upper active layer of the sea. The necessity of creation of a complex of this sort is justified and a circle of problems that can be solved with the help of this complex is described. The scales of resolution of horizontal and vertical inhomogeneities in measuring in the mode of vertical probing are theoretically estimated. The basic technical characteristics of the complex are presented. We also present the results of laboratory and field tests, which confirm the agreement between the calculated and actual technical possibilities of the complex. The structural features of various versions of the “Sigma-1” measuring complex (the “Sigma-1P” point-to-point-operation version and the “Sigma-1Z” probing version) are described. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 60–71, September–October, 2005.     

Bottom boundary layer in the Black Sea: formation of the stationary state

We make an attempt to answer the following question: how a natural stationary system formed by a layer and an interface “selects” a unique set of governing parameters from a great number of possible collections under the conditions of double-diffusion layer convection (e.g., for the bottom boundary layer in the Black Sea)? As the “rule of selection,” we use the principle of minimum entropy production for systems close to the state of thermodynamic equilibrium. In the process of solution of the problem, the system is regarded as a heat engine. The proposed approach is reduced to a simple procedure of application of the principle of minimum entropy production to the analyzed case. The combined analysis of the theoretical results, the data of deepwater field measurements in the Black Sea, and the results of laboratory experiments leads us to the conclusion that, most likely, the stationary system “selects” its governing parameters according to the Prigogine–Glansdorff principle. The density ratio (approximately equal to three for the stationary case) proves to be the key parameter of the system. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 16–25, January–February, 2009.     

Effect of finely divided admixtures on the scattering of light in “pure” filtered water

We consider the problem of disagreement between the theoretical and experimental values of the spectral volume scattering function of “pure” filtered water. To explain this disagreement, we advance a hypothesis of existence of two-dimensional space correlations between the locations of a finely divided suspension in the liquid. We deduce analytic relations for the scattering of light in the approximation of statistically equilibrium distribution of particles over the surfaces of spheres randomly arranged in the medium. The experimental data on the volume scattering function of “pure” filtered water (the sizes of particles do not exceed 0.2 μm) are analyzed. The results of numerical analysis according to the model of spherical surface distribution of finely divided particles in water are in qualitative agreement with the spectral volume scattering function of filtered water. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 46–56, March–April, 2008.     

Detection of Mediterranean lenses in the Atlantic ocean by profilers of the Argo project

We executed investigations of Mediterranean lenses detection in the Atlantic using data recorded by buoys-profilers of the “Argo” project (more than 11200 profiles). We investigate the region from 28° to 47° N and from 7° to 27° W for the period from 2001 to 2010. From these data, we revealed “lenses profiles” with the salinity values exceeding 36 psu (2043 cases). We demonstrate the allocation of Argo buoys in the area investigated and indicate their working periods; we also show the periodicity of the “lenses profiles.” It was found out that the Argo buoys traced individual lenses and depicted correctly their movements, the vertical scale of the eddy, its location in the depth, and the hydrological peculiarities of the lenses. We estimated the number of lenses occurring in different periods and analyzed the interaction of the Argo buoy with the intrathermocline lenses. The importance of these investigations for studying the Mediterranean water dynamics was pointed out.     

Drifter Observations of Anticyclonic Eddies near Bussol' Strait, the Kuril Islands

Hydrographic surveys and satellite imaging reveal that mesoscale anticyclonic (AC) eddies are common features of the area south of Bussol' Strait, the deepest of the Kuril straits connecting the western North Pacific and Sea of Okhotsk. To examine the velocity structure of these eddies, we deployed groups of 15-m drogued satellite-tracked surface drifters over the Kuril-Kamchatka Trench in the fall of 1990 and late summer of 1993. Drifters in both groups entered large AC eddies centered over the axis of the trench seaward of Bussol' Strait and subsequently underwent a slow northeastward translation. One drifter (Drifter 1315) deployed near the center of the “Bussol' eddy” in 1990, remained in the eddy for roughly 45 days and made five loops at successively greater distances from the eddy center. Large-amplitude (80–100 cm/s) storm-generated inertial oscillations were observed during the first two loops. The vorticity field associated with the eddy resulted in a Doppler “red-shift” of inertial frequency motions such that the “effective” inertial period of 21 hours was roughly 4 hours greater than the nominal inertial period for the drifter latitude (45°N). In 1993, a second drifter (Drifter 15371) was retained in the Bussol' eddy for about 40 days. This eddy had characteristics similar to those of the 1990 eddy but was devoid of significant high-frequency motions until the drifter's final half loop. The observed spatial scales, persistence, and slow poleward translation of the eddies suggests that they play an important role in the dynamics of the East Kamchatka and Oyashio current systems. This revised version was published online in August 2006 with corrections to the Cover Date.     

Basic regularities of the formation of “new” and regeneration production in the Black Sea

Based on the experimental data obtained in 1990–1993 by the method of isotopic tracers with the help of a stable isotope of nitrogen (¹⁵N), we establish basic regularities of the formation of “new” and regeneration production in the Black Sea and reveal the factors specifying their combination. It is shown that the rates of nitrate and ammonium uptake by microplankton vary from the minimum values in winter to the maximum values in summer. In the surface layer, the uptake of nitrates corresponding to the amount of “new” production in deep-water layers is equal to ∼ 50% (in winter) and ∼ 30% (in summer) of the total uptake of inorganic nitrogen compounds by microplankton. In the zone of photosynthesis, the average fractions of nitrates are equal to 31 ± 10% in winter and 41 ± 10% in summer. The minimum values of this parameter are attained in the middle of spring and in autumn. The fraction of “new” production (f-ratio) and the integral content of nitrates in the zone of photosynthesis are connected by a hyperbolic dependence. The period of cyclic transformations of nitrates in this zone decreases from several dozens of days at the beginning of winter to 12 h in the mid-spring. In summer, this period is equal, on the average, to one day. The average period of cyclic transformations of ammonium is equal to 15 ± 4 h in winter and 5 ± 3 h in summer. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 29–43, November–December, 2006.     

On the transformation of the chemical composition of the Volga River discharge waters at the Caspian shallows

The Volga River discharge consists of the waters transferred by fast currents through channels and the waters which are passing through the shallow areas of the delta overgrown by cane. Using the hydrochemical data, it is possible to track distribution of the waters modified by “biofilters” of macrophytes in the delta shallows starting from the external edge of the delta. The main distinctive features of these waters are the high content of dissolved oxygen, the abnormally high values of the pH, and the low content of dissolved inorganic carbon (both total and as CO₂). These waters extend in the shape of 1 to 3-km-wide strips at a distance of 20–40 km from the outer border of the delta. The analysis of the data obtained during the expeditions run by the Institute of Oceanology of the Russian Academy of Sciences in 2003–2009, along with archived and published data, show that such “modified” waters occur almost constantly along the outer edge of the Volga River delta.     

Numerical Method for the Solution of the Equation of Radiation Transfer. Reflection and Transmission Coefficients for an Optically Thin Plane-Parallel Layer

We study the problem of the choice of initial approximation for the reflection and transmission coefficients in numerical methods based on the principle of “interaction.” The disadvantages of the approximation of single scattering are demonstrated and the regularities of propagation of light in media with strongly anisotropic scattering are analyzed. Semianalytic expressions proposed for the evaluation of the initial approximation enable one to determine the characteristics of the light field in plane-parallel media with relative errors of about 10⁻⁵ within the framework of the algorithm of “adding” of layers. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 62–72, May–June, 2005.     

Upwelling of oxygen-depleted water (Sumishio) in Omura Bay,Japan

Wind-induced circulation and the distribution of hypoxia corresponding to the upwelling of oxygen-depleted water (called “Aoshio” in Japan and “Sumishio” locally in Omura Bay) in Omura Bay, Japan, was examined field observations and by three-dimensional modeling. During the calm weather in summer, well-mixed strait water, in rich oxygen at the mouth of the bay intruded into the middle layer of the bay, southward and northward along the west and east coast, respectively, forming basin-scale cyclonic circulation. A stagnant water mass was formed below the center of this cyclonic circulation, and it became hypoxic water. As a result of the prevailing strong southeast (northeast) wind, the bottom hypoxia moved in a southeasterly (northeasterly) direction. This induces the upwelling of hypoxic water, accompanied by mass mortality of marine organisms.     

Correspondence between Lagrangian and Eulerian Velocity Statistics at the ASUKA Line

The 20–30% differences between drifter- and altimetry-derived mean velocities reported at the ASUKA line (Affiliated Surveys of the Kuroshio off Cape Ashizuri) are explained in terms of the non-Eulerian character of statistics of drifter trajectories' crossovers with the TOPEX/Poseidon track. Larger mean drifter velocities are shown to result from the fact that more water crosses the line when velocity is large, so that the “line” average velocity corresponds to the Eulerian quantity <V⋅|V_n|>/<|V_n|>, where V_n is a velocity component perpendicular to the line. Practical methods are suggested to correct the bias. General properties of the “line” statistic and improvement of dynamical balance by correct accounting for the acceleration term are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Correction of atmospheric effect on ADEOS/OCTS ocean color data: Algorithm description and evaluation of its performance

This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model” introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670 and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances, and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the estimation error of the “weighted average” scheme is mostly within the permissible level of ±0.002, reducing the error by 18% on average compared to the “simple average” scheme. The paper further discusses the expected error under the old CZCS-type atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration waters, indicating the necessity for future improvements.     

The concept of “representative tides” in morphodynamic numerical modelling

Process-based numerical modelling of coastal morphodynamics involves model and data reduction schemes in order to cope with computational limitations. Model reduction, on the one hand, may involve the discretisation of an interactive multidimensional, diverse natural system into a reduced set of coupled process-simulation modules. Data reduction schemes, on the other hand, are used to parameterise processes. The use of schematised open-boundary conditions, which are considered as representative in terms of their cumulative morphological effect, is based on the concept of “morphological” or “representative” boundary conditions. Recent model applications show realistic tendencies in terms of depositional and erosional areas. By contrast, the reproduction of characteristic changes in morphology such as the migration of bars, banks and channels is only occasionally achieved. Using field data on observed morphological impact of a single storm event and numerical model data, it is demonstrated that the concept of representative tides may lead to simulations of morphological development lacking natural dynamics. It is proposed that rather than being based on “representative” single tides, morphodynamic models should be applied with open-boundary conditions which take variations in longer-term tidal and meteorological forcing into account.     

Two-dimensional analysis of the semidiurnal tide in some regions of the white sea

An improved method of two-dimensional kinematical structural analysis of tides (the “method of the orbits”) is presented. This method allows us to determine the parameters of the primary tidal waves shaping the observed tidal structure. The construction of the vertical orbits for the individual tidal harmonics is performed along the horizontal coordinate axes; one of them is oriented along the so-called “reactive azimuth,” which coincides with the direction of the tidal current at the instant of the zero tidal level. In this case, the orbit parameters include information on the amplitude-phase relations of the interfering waves and allow us to determine the angle of the waves crossing. The suggested method enables us to quantitatively describe the mechanism of the tidal formation with oblique interference both close to the shore and in the open sea. We tested the new method in two local zones of the White Sea (Morzhovets Island and in the vicinity of the entrance to Kandalaksha Gulf) where the presence of rotating semidiurnal tidal currents evidences the significant role of oblique interference of tidal waves. In these zones, the developed method made it possible to perform a detailed quantitative analysis of the local tide structure caused by the M₂ tidal wave, which plays the dominant role in the White Sea. The result describes the structure of the propagation of the primary tidal waves better than the field of “pure” energy fluxes that was used earlier.