Abstract New data on the geological structure and genesis of relict bottom relief forms, objects of underwater cultural heritage, and the structure of bottom sediments in the Baltic Sea were obtained during cruise 47 of the R/V Akademik Nikolaj Strakhov (June 25–July 4, 2020). Geomorphological features of submerged ancient coastal cliffs have been specified, large sand bodies have been identified at

Abstract—The paper gives brief results of comprehensive studies in the South China Sea obtained from a joint Russian–Vietnamese expedition in November 2019 (cruise 88 of the R/V “Akademik M.A. Lavrentyev”). The set of methods included acoustics, geophysics, geology, mineralogy,geochemistry, paleogeography, geomicrobiology, hydrooptics and hydrology. The seafloor relief, geophysical and gasgeochemical

Abstract During cruise 43 of the R/V Akademik Nikolaj Strakhov (September 21–October 9, 2019), new data were obtained on the bottom relief, sedimentation, and hydrological regime of the Discovery Gap (eastern North Atlantic). It was shown that the upper limit of the Antarctic Bottom Water in the study area follows the 2.05°C isotherm and 34.91 PSU isohaline at depths of 4400–4700 m. A digital elevation

Abstract The multidisciplinary expedition “European Arctic-2020” on board the R/V Akademik Mstislav Keldysh took place from July 31 to August 26, 2020. The investigations were carried out in the Norwegian Sea on the Mohns Mid-Oceanic Ridge (including the hydrothermal activity zone near Jan Mayen), near gas seeps in the Storfjord Trough, on the polar front in the Barents Sea, and on the continental

Abstract Studies have been conducted to assess the functioning of the marginal filter in tidal estuaries of small rivers of the Arctic seas. For this, we used observational data in the White and Barents seas. When extensive tidal drains and thickets of halophytes exist in the mouths of small rivers, biogeochemical processes can differ markedly from the conditions described by the classical marginal

Abstract This work is focused on the river plume generated by the Kodor River which is the largest river of Abkhazia and the northeastern coast of the Black Sea. Based on in situ hydrological data, quadcopter aerial images and satellite observations, hydrophysical structure and circulation in the Kodor plume was studied at different river discharge conditions. Discharge of the Kodor River, which inflows

Abstract The paper presents new data on concentrations and fluxes of organic carbon, iron, and manganese in waters of the mouth area of the Northern Dvina River. The work was conducted within the project “Northern Dvina River Marginal Filter Observatory” from May 2015 to May 2019 with monthly collection of water samples. Systematic determinations of the concentrations of the main carrier elements of

Abstract Large-scale monitoring of anthropogenic marine litter in the Barents Sea was carried out in 2012–2018. The marine litter composition was estimated by recording by-catch from pelagic and bottom trawling. Litter on the sea surface (floating litter) was also taken into account during visual observations. The contents of 949 pelagic and 1477 bottom trawls were analyzed. Marine litter was recorded

Abstract The OCP and PCB contents in the tissues of beluga whales (Delphinapterus leucas) from the Russian Arctic have been studied for the first time. Skin and subcutaneous adipose tissue samples collected in the White, Kara, and Bering seas in 2012–2017 were analyzed for the animals of different age and sex (n = 22). 4,4'-DDE dominated among the OCPs analyzed; the main PCB congeners were PCB-138+PCB-158

Abstract For the first time, the results of a study of ore sands formed during storm waves and winds on the sea beach of Curonian Spit and in the quieter wind environment on the beach of the Curonian Lagoon are presented. The mineral composition and the sources of their supply to the beaches have been determined. Conclusions are given on the practical and theoretical significance of the ore content

Abstract—Hydrogenetic Fe–Mn crusts in the ocean are enriched in platinum but do not accumulate palladium. The mechanism of platinum input into the crusts remains debatable. There is even less data on ruthenium and iridium. In this article, the distribution of platinum group elements (Pd, Ru, Ir, Pt) in ferromanganese crusts of the Detroit guyot (Northwest Pacific) is studied. Based on correlation analyses

Abstract The article presents the results of hydrochemical studies of the rivers of the Abkhazian coast of the Black Sea in April 2019. The Kodor River with its plume was the main object of the study, and additional samples were drawn from the small rivers of Kelasur, Mokva, and Galizga. Kodor River water was shown to contain nutrients at high concentrations (1.35 µM phosphates, 128.5 µM silicates

Abstract At the Black Sea research site Gelendzhik of the Shirshov Institute of Oceanology (IO RAS), a technique has been established for joint current velocity profile measurements using towed ADCP and periodic CTD soundings from on board of the mini R/V Ashamba with high spatiotemporal resolution. In this case, CTD soundings are taken from the sea surface to the bottom layer according to an original

Abstract— The study examines changes in the abundance (density) and distribution of European Sprattus sprattus (Linnaeus, 1758) eggs and larvae, as well as the phenology of its spawning depending on hydrologic factors and abundance of gelatinous macroplankton in the Black Sea in November 2016–2017. An increase in temperature of the sea surface layer observed since the beginning of the century and the

Abstract The effects of oceanic and biotopic factors on the size and age at maturity of sea urchins Strongylocentrotus intermedius alongside the northwestern coast of Primorsky krai are discussed. The growth rate and body size of the sea urchin at 50% maturity of the population corresponds to 30–35 mm in clusters with high growth rates and to 20–22 mm in clusters with low growth rates. In populations

Abstract The geological-structural, magmatic, seismic, and thermometric models of the Earth’s crust and upper mantle of the Sea of Japan region are considered in relation to three-dimensional rheological gravity models reflected in horizontal and vertical sections of density contrast of the tectonosphere. In the crust and the upper mantle, formal manifestations of a right-lateral strike-slip duplex

Abstract On cruise 76 in 2019, the R/V Akademik Mstislav Keldysh completed the Gulf of Ob–Kara Sea slope transect. Samples of bottom water and two sediment layers 1 cm thick were obtained with a multicorer. The silicon, mineral and total phosphorus, and organic nitrogen concentrations were measured in them. The magnitude of fluxes of these nutrients at the water–bottom boundary along the transect was

Abstract Herein we provide information on the sedimentological and paleoceanographic research on the Argentine Patagonian continental slope during cruise 79 of the R/V Akademik Mstislav Keldysh in March 2020. The preliminary scientific results are discussed.

We present a high-resolution historical analysis of the atmosphere over the North Atlantic for the period from January 1979 to December 2018. The dataset was obtained using the nonhydrostatic atmospheric model WRF-ARW version 3.8.1 and contains two experiments that differ in spatial resolution: 14 km (HiRes) and 77 km (LoRes). Except for the spatial resolution, the configuration remained identical

Abstract This article presents a data set on ash, proteins, lipids, carbohydrates, chitin, organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) contents, macronutrients ratio (C, N, and P) and energy content of zooplankton (size fraction >500 μm) from the Kara Sea. Zooplankton samples were collected at 22 stations during the 76th interdisciplinary cruise of the R/V “Akademik Mstislav

Abstract The research is based on the materials collected during cruise 66 of R/V Akademik Mstislav Keldysh in the Yenisei estuary and over the adjacent Kara Sea shelf in the latitudinal range from 71°50.5′ to 75°55.0′ N. The studies were performed from July 25 to 27, 2016, three weeks after the end of the flood period. Two hundred fifty species of plankton algae were recorded. Well-pronounced latitudinal

Abstract The seasonal occurrence and distribution of the pelagic larvae of large burrowing shrimps of infraorders Gebiidea and Axiidea, leading a hidden lifestyle, were studied in the Vostok Bay (Peter the Great Bay, the Sea of Japan) from May through September 2014. Zoea of the burrowing shrimps were found from the end of May to the end of September, at a water temperature of 12.3–23.4оС, reaching

Abstract Transformation of the chemical composition of seawater upon interaction with loess, an analog of natural terrigenous aerosols of the Pleistocene, was studied experimentally. It was shown that this process leads to a change in the concentrations of major ions (K, Ca, SO4, and HCO3), nutrients (Si and P), and fluorine, while the chloride, sodium, and magnesium contents do not vary due to their

The article is devoted to the development of an autonomous profiling system for measuring the aquatic environment under ice. The system moves up and down in the water column along a cable with a load at the lower end, which is lowered into a lane in the ice. The system carrier is designed for transporting an acoustic Doppler current profiler and a salinity, temperature, and pressure probe. The system

The paper presents data from a granulometric analysis based on the results of studying of 44 surface (0–5 cm) sediment samples obtained on cruise 67 of the R/V Akademik Mstislav Keldysh (2016) from different parts of the Barents Sea. Pebble and gravel material is found in surface sediments as an admixture scattered throughout the sea. Such a chaotic distribution pattern is apparently associated with

Abstract— The results of an analysis of wave observations in Dvoinaya Bay at the southern part of Matua Island (Kuril Ridge) are reported. Experimental studies were carried out in order to determine the probability of amplifying the incoming waves in the coastal zone of the island. The observations provided the records of waves at two points of the bay located at depths of ~10 and 20 m, with a discreteness

Abstract— Interannual variability (2002–2018) of primary production, surface seawater temperature (T0), photosynthetically active radiation (PAR) and ice cover area in the East Siberian Sea (ESS) was studied based on the data of the MODIS-Aqua ocean color scanner. The annual total primary production (PPtot) decreased by 1.7 TgC over 17 years. The multi-year negative trend in PPtot was 0.1 TgC y–1 (1

We have summarized the results of studies of bottom rock material in Quaternary sediments in the polar seas of the Arctic, North Atlantic, and Antarctica, obtained by sieve washing on expeditions of the Shirshov Institute of Oceanology, Russian Academy of Sciences. We have compiled maps of the quantitative distribution of this material over water areas and created pie charts of the petrographic composition

Abstract This study was based on data obtained during the cruise 63 of the R/V Akademik Mstislav Keldysh in September 2015. We examine the features of the hydrochemical structure of the Lena River–Laptev Sea mixing zone. The studies were carried out in the eastern part of the Laptev Sea on a quasi-meridional transect, with the length of 710 km along 130°30' E. The distribution of dissolved oxygen,

A new area of oceanography, operational oceanography, involves a comprehensive assessment and forecast of the variability of the state of the marine environment. This requires systematic study of numerous natural parameters, the creation of integrated measurement systems for the properties of the water column and seafloor, rapid data collection and transmission systems, assimilation of new data in

Abstract The content of 53 micro- and ultramicroelements in otoliths of two deep-sea fish species, blue antimora Antimora rostrata from the Northwest Atlantic (NWA) and Pacific flatnose Antimora microlepis from the Northeast Pacific (NEP), is studied. The otoliths of these species were characterized by the maximum concentration of strontium, nickel, zinc, barium, chromium, copper, lithium, cobalt,

Abstract The results on the content, composition, and distribution of chloroform bitumoids (CBs) in the Holocene sediments of the Barents Sea are presented (Cruise 68 of the R/V Akademik Mstislav Keldysh, July–August 2017). Depending on the sedimentation conditions, CB concentrations varied on average (μg/g of dry mass) as follows: Novaya Zemlya Archipelago (174) > Svalbard Archipelago (131) > Western

This paper reports the results of investigations on the radioecological state of bottom sediments of the Ob–Yenisei shoal area and Ob and Yenisei estuaries. Materials were obtained in two periods: 1995–2001 and 2014–2019 during seven expeditions on the R/V Akademik Boris Petrov, Professor Shtokman, and Akademik Mstislav Keldysh. Resampling of bottom sediment cores at key-points in areas of increased

Abstract Measurements of currents and Antarctic Bottom Water properties overflowing the sill from the Weddell to the Scotia Sea are described. The bottom water overflows the sill of one of the passages through the South Scotia Ridge (eastern part of the Philip Passage approximately at 48° W). A weak flow of Weddell Sea Deep Water to the north was found. The northward flow was recorded only in the western

Abstract Field works on cruise 79 of the R/V Akademik Mstislav Keldysh aimed at investigating the ecosystems in the Atlantic sector of Antarctica were conducted from January 16 to March 1, 2020. Hydrophysical and biological studies were carried out in the Drake Passage and the Bransfield and Antarctic Sound straits. The regions of Russian fishery interest were covered. Data were collected that characterize

Abstract Results of a mesoscale survey in the Powell Basin in the northern part of the Weddell Sea are analyzed. The survey included 24 CTD casts (6 × 4) with an interval of six nautical miles. Measurements of water transparency, fluorescence, and plankton catches using the Bongo and Jedy nets were performed. The survey covered a region of an oceanographic front. The front is manifested by sharp horizontal

A comparative description of sedimentary matter in the snow–ice cover of the Circumpolar Arctic and fast ice of the Antarctic is given. The main distribution patterns of dispersed sedimentary matter in the marine cryosystem of snow–sea ice–ice water of the Arctic and Antarctica are obtained. Sedimentary matter fluxes from the bottom of sea ice to the ocean bottom are calculated.

Abstract The key indicators of marine sediment genesis are the particle size distribution (PSD) and volume concentration of suspended particulate matter (SPM). However, their study is not widespread in ship oceanology research. This paper reviews experience in using the LISST-Deep laser particle size analyzer for the study of marine SPM in situ. We present the first data on the volume concentration

Abstract The benthic fauna of Sedova Bay (Kara Sea, Novaya Zemlya Archipelago) was studied during two cruises of the R/V Academik Mstislav Keldysh in 2015–2016. Three macrobenthic communities were described. The species composition of the benthic communities is formed by two orthogonal environmental gradients: vertical (depth) and horizontal (the distance from the apex of the bay). Horizontal changes

Abstract The geological structure and bathymetry of the deepwater part of the South Caspian indicate the possible formation of significant amounts of gas hydrates. The aim of the research is to calculate the volume of hydrocarbon gases of gas hydrates according to integrated geological–geophysical, geochemical, and thermodynamic data, as well as to study and predict the migration of hydrocarbon gases

Abstract In Russian Arctic seas, observations of surface methane concentrations (CH4), ozone, nitrogen and carbon oxides, as well as the content of \({{\delta }^{{13}}}{{{\text{C}}}_{{{\text{C}}{{{\text{H}}}_{4}}}}}\) isotope and black carbon (BC, soot aerosol), were carried out from onboard of the R/V Academician Mstislav Keldysh. The areas of local methane releasing from bottom sediments were investigated

Abstract A flow-through measuring complex has been created for continuous underway measurements of bio-optical characteristics (fluorescence intensities of chlorophyll a and dissolved organic matter, along with the beam attenuation coefficient of seawater) and hydrological quantities (salinity and temperature). Compared to previous versions, the complex measures more characteristics and features wider

A model is developed to simulate the morphodynamics of a barred shore profile on the scale of a storm cycle, comprising the phases of high and low wave activity. In the CROSS-PB model, the main mechanisms governing sediment transport in wave shoaling and surf zones are taken into consideration, in particular, skewness and asymmetry of the wave orbital velocities, undertow, and infragravity oscillations

Abstract— Studies of seasonal variability of the East Siberian Sea (ESS) water column primary production (IPP) and evaluation of its total annual value (PPtot) were performed using MODIS-Aqua data (2002–2018). Region-specific primary production and chlorophyll algorithms were used for the first time to achieve that result. Northeastern and Southwestern regions were distinguished in ESS based on multiyear

Abstract The characteristics of the abiotic environmental parameters obtained during in situ observations and significant for the survival of cod eggs and larvae (water salinity, water temperature, and oxygen content) are presented for the Baltic Sea for 2016. Cod eggs were present in ichthyoplankton during the entire spawning season (March–August). In July and August 2016, the abundance of cod larvae

Abstract The Osborn Plateau is a large intraplate elevation in the eastern Indian Ocean, which has been poorly studied by geological and geophysical methods. On cruise SO258/1 aboard the R/V Sonne, new data were collected by Parasound seismic processing, multibeam survey, and, for the first time, dredging. Faults in the sedimentary cover, which extend to the seafloor surface, indicate high neotectonic

Abstract The article presents results of field research on environmental assessment in Abrosimov Bay (Yuzhny Island of Novaya Zemlya) in connection with the existing RW disposal sites in this region. In the course of the studies, technology was created based on the original remotely and unmanned towed underwater vehicles (ROV and TUUV), as well as special side scan sonar (SSS). To specify the state

Abstract The lithological and mineralogical characteristics of sea surface sediments, composition of microfossils, contribution of organic matter, and element composition have been studied in a core from the northern part of East Novaya Zemlya Trough. Sedimentation rates were calculated based on the radioisotopes 210Pb and 137Cs. Lithological, biogeochemical, and geochemical studies showed a low variability

Abstract The 49th cruise of the R/V Akademik Sergey Vavilov (August 29–September 7, 2019) allowed to obtain new data on the Baltic Sea geological history and the current state of its ecosystem under eutrophication conditions. The size and shape of the Gotland contourite drift, as well as the Major Baltic inflow pathway in the Baltic Proper were specified. The conditions of hypoxia and anoxia in combination

Abstract New data on the formation of the bottom topography, bottom sediments, spatial structure and dynamics of waters of the Baltic Sea were obtained in cruise 42 of the R/V Akademik Nikolaj Strakhov (August 17–27, 2019). The distribution, morphology, and structure of large sand bodies on the Rybachy plateau were obtained. Additional data on the formation of the bottom topography and sedimentation

Abstract Geological, hydrological, hydrochemical, and biological research has been carried out in the eastern tropical Atlantic. Based on the multibeam echo-sounding and seismic profiling north of the Kane Gap (Sierra Leone Rise), an extensive sedimentary body (contourite fan) has been identified. Data of hydrophysical sounding allows assuming the existence of an overflow of the Antarctic Bottom Water

Abstract The first sampling of mantle horizons underlying the ophiolite peridotite complex of the Mariana back-arc basin was carried out based on a spinel lherzolite xenolith in basanites from the submarine Esmeralda Volcano. The paper shows significant differences between the bulk, petrological, geochemical, and mineralogical compositions of this xenolith and similar characteristics of ophiolite peridotites

Abstract It is proposed to use data on the hydrocarbon content in phytoplankton contained in a studied water sample to calculate the biogenic background of hydrocarbons, without which the assessment of the degree of oil pollution of aquatic ecosystems would be incorrect. Algae were grown in sterile flasks to accumulate the biomass required for analysis. The amount of hydrocarbons isolated from lipid

Abstract— Samples were collected in the area of the St. Anna Trough in the northern Kara Sea in September 2015 and July–August 2016. Based on salinity and temperature distribution, four areas have been distinguished: the shelf adjacent to the St. Anna Trough, the shelf edge, and the upper and lower parts of the continental slope. The variability of the structure of phytoplankton communities has been

Abstract Analysis of zooplankton collected on five cruises (2007–2016) in the Kara and Laptev seas has revealed considerable heterogeneity in the spatial distribution of the biomass of the pteropod Limacina helicina, one of the important components of the Arctic zooplankton. The biomass and abundance of mollusks in 2014–2016 were significantly lower than in the previous period, in 2007 and 2011. The

Abstract Data on temporal (July and September) and interannual variations in the content of several heavy metals are presented for the body wall, gonad, and gut of the sea cucumber Eupentacta fraudatrix from coastal waters of two inlets of Peter the Great Bay (Sea of Japan) with different levels of anthropogenic pollution. The gonads mostly accumulate Zn, Fe, Cu and Cd, while the body wall, presumably

Abstract This paper reports the results of investigations in September 2017 on the radioecological state of bottom sediments of the East Siberian Sea during integrated research of the Siberian Arctic seas on cruise 69 of the R/V Akademik Mstislav Keldysh. Evaluation of the results of γ-spectrometric analysis found that the current specific activity of artificial cesium-137 in sediments is two orders

Abstract We studied sedimentation processes in the Lofoten Basin of the Norwegian Sea based on data of the Automatic Deep-Sea Sedimentation Observatory (ADSO) deployed for a year (August 2017–July 2018). The article presents estimates of the vertical fluxes of total sedimentary material, organic carbon (Corg), calcium carbonate (CaCO3), biogenic silica (SiO2bio), aluminum, and the particles of planktonic

Abstract Picophytoplankton abundance, biomass, and chlorophyll a concentration as well as contribution of picoalgae to total chlorophyll a, and species composition of phototrophic picoeukaryotes (cells size less than 3 µm) were studied in Blagopoluchia Bay (Novaya Zemlya archipelago) and the northwestern part of the Kara Sea in September 2017. In the Bay, the highest picophytoplankton abundance and

Abstract Shelf currents are formed by the wind, tides, and pressure gradient. Wind is usually the dominant energy source for coastal currents. This paper considers the formation of the coastal current under the effect of push-off wind and its influence on the thermohaline structure of Peter the Great Bay waters. When wind increases, a strong coastal current forms along the isobath and a transverse