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Gelendzhik, Russia

The Shirshov Institute of Oceanology RAS, Russian: Институт океанологии им. П. П. Ширшова РАН) in Moscow, is the largest institute for ocean and earth science research in Russia, established in 1946. It is part of the Russian Academy of science. Wikipedia.

Krylova E.M.,RAS Shirshov Institute of Oceanology | Sahling H.,University of Bremen

Vesicomyid bivalves are a consistent component of communities of sulphide-rich reducing environments distributed worldwide from 77° N to 70°S at depths from 100 to 9050 m. Up-to-now the taxonomy of the family has been uncertain. In this paper, the current state of vesicomyid taxonomy and distribution at the generic rank are considered. This survey is founded on a database including information both from literature sources and also unpublished data of the authors on all recent species of vesicomyids. We suggest that the Vesicomyidae is not a synonym of Kelliellidae, and is therefore a valid family name. We propose to divide the family Vesicomyidae into two subfamilies: Vesicomyinae and Pliocardiinae. The Vesicomyinae includes one genus, Vesicomya, which comprises small-sized bivalves characterized by non-reduced gut and the absence of subfilamental tissue in gills. Symbiosis with chemoautotrophic bacteria has, so far, not been proved for Vesicomya and the genus is not restricted to sulphide-rich reducing habitats. The subfamily Pliocardiinae currently contains about 15 genera with mostly medium or large body size, characterized by the presence of subfilamental tissue in the gills. The Pliocardiinae are highly specialized for sulphide-rich reducing environments, harbouring chemoautrophic bacteria in their gills. This is the first summary of the generic structure of the family Vesicomyidae that allow us to analyze the distribution of vesicomyids at the generic level. We recognize here five different distribution patterns that are related to the specific environmental demands. The general trends in the distribution patterns of the vesicomyids are an occurrence of the majority of genera in broad geographical ranges and the prevalence of near continental type of distribution. © 2010 Krylova, Sahling. Source

Shiganova T.,RAS Shirshov Institute of Oceanology
Annual Review of Ecology, Evolution, and Systematics

Comparative analysis of patterns of species invasion, dispersal, and impact on ecosystems in the Ponto-Caspian seas has been ongoing since 1900. The Black Sea is an important international shipping destination. High shipping intensity has facilitated species invasions into the Black Sea. Many species have successfully established because of Black Sea disturbances. The Black Sea serves as a hub for species that then spread further to the Sea of Azov, the Caspian Sea, the Sea of Marmara, and in some cases the eastern Mediterranean Sea. The Black Sea has thus become the main recipient for non-native species and acts as a donor to the seas of Eurasia. Native biodiversity has declined and invaders now dominate the Ponto-Caspian seas. This process has caused biotic homogenization of the Ponto-Caspian, as the same invaders determine community structure and in some cases ecosystem functioning in the different seas. Among these invaders, gelatinous species have become the main drivers of ecosystem functioning. The invasion rate of new species is accelerating. Copyright © 2010 by Annual Reviews. All rights reserved. Source

Reznik G.M.,RAS Shirshov Institute of Oceanology
Journal of Marine Research

Linear dynamics of stably-neutrally stratified fluid consisting of the stably stratified upper layer and the homogeneous lower layer is studied with and without rotation. The density and other fields are continuous at the interface between the layers. A special feature of this configuration is existence of the wave mode related to the homogeneous layer. In non-rotating fluid this is the homogeneous layer vortex mode characterized by a stationary three-dimensional velocity field confined to the lower layer. In the presence of rotation, the mode turns into the gyroscopic waves. Besides the mode, the wave spectrum contains internal waves and the zero frequency horizontal vortex mode with zero vertical velocity. In non-rotating fluid, the vertical velocity consists of the dispersive internal waves and of a steady component in the homogeneous layer. With increasing time the internal waves decay at a fixed point because of dispersion, and the vertical velocity decays in the upper layer and becomes stationary in the lower layer. A non-stationary boundary layer develops near the interface in the stratified layer at large times. In rotating fluid we examined the wave spectrum not using the traditional and hydrostatic approximations, and found the spectrum consists of the super-inertial internal waves, the sub-inertial gyroscopic waves and the sub- and super-inertial internal inertio-gravity waves. In the case of strong stratification f/N « 1(f is the inertial frequency and N is the stratified layer buoyancy frequency) and for the long wave scales f 2 /N 2 « H/L « 1(H and L are the fluid depth and the horizontal scale), the internal and the super-inertial inertio-gravity waves freely penetrate into the lower layer, and the gyroscopic waves are localized in the lower layer and are close to the inertial oscillations. Any long-wave field of the vertical velocity is split into the internal waves, and the inertial oscillations (long gyroscopic waves) confined to the lower layer. With time, the internal waves decay because of dispersion, and the vertical velocity goes to zero in the upper layer and in the lower layer only the inertial oscillations remain. © 2013 Gregory M. Reznik. Source

Prokofiev A.M.,RAS Shirshov Institute of Oceanology
Journal of Ichthyology

Deepsea herrings of the northwestern Pacific (waters of Japan and Taiwan) are revised. Three species are recognized in this area, and two of them described as new: B. gracilis Fowler, 1938, B. japanotaiwana sp. n., and B. nikparini sp. n. B. japanotaiwana was previously mistakenly identified as the western Atlantic species B. argentea; actually it is especially similar to B. malayana, from which it differs in the bicolor oral cavity and in some meristic characters. B. nikparini is especially close to the Caribbean species B. schroederi, from which it differs in a greater number of developed gill rakers and smaller number of rays in the anal fin. © 2014 Pleiades Publishing, Ltd. Source

Agafontsev D.S.,RAS Shirshov Institute of Oceanology
JETP Letters

We examine statistics of waves for the problem of modulation instability development in the framework of discrete integrable Ablowitz-Ladik (AL) system. Modulation instability depends on one free parameter h that has the meaning of the coupling between the nodes on the lattice. For strong coupling h ≪ 1, the probability density functions (PDFs) for waves amplitudes coincide with that for the continuous classical nonlinear Schrödinger equation; the PDFs for both systems are very close to Rayleigh ones. When the coupling is weak h ∼ 1, there appear highly localized waves with very large amplitudes, that drastically change the PDFs to significantly non-Rayleigh ones, with so-called “fat tails” when the probability of a large wave occurrence is by several orders of magnitude higher than that predicted by the linear theory. Evolution of amplitudes for such rogue waves with time is similar to that of the Peregrine solution for the classical nonlinear Schrödinger equation. © 2013, Pleiades Publishing, Inc. Source

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