Abstract—The large-scale expedition of cruise 76 of the R/V Akademik Mstislav Keldysh was performed by the Shirshov Institute of Oceanology from July 1 to August 6 2019 within the Program “Marine Ecosystems of the Siberian Arctic.” Seventy-one scientist from Russian Academy of Sciences institutes, Moscow State University, and VNIRO participated. Coordinated hydrophysical, hydrochemical, biooceanological

Abstract The paper presents information on geochemical and mineralogical investigations of sedimentary rocks carried out in April 2019 in the Northern Morocco. A set of data on mineral and chemical composition of the Late Miocene deposits was obtained in the region of the contourite paleo-channel. The obtained results improved lithological description of the studied outcrops and confirmed the significant

Abstract The coast of the shallow Azov Sea is characterized by a series of sand spits. Based on the results of drilling conducted on Dolgaya Spit, which separates the water area of Taganrog Bay from the rest of the Sea of Azov, we consider the structure of the upper part of the geological section of these coastal accumulative forms. Core samples obtained during drilling made it possible to determine

Abstract According to the Plan of Complex Scientific Research of the World Ocean for 2017–2022, the V.I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, continues to study the northern part of the Sea of Japan and the Tatar Strait, carrying out a three-year plan of expeditionary research of this region. The expedition aboard the R/V Akademik Oparin (cruise

Abstract The coefficients of selectivity of a nitrate-selective electrode to \({\text{C}}{{{\text{l}}}^{ - }}\), , and \({\text{SO}}_{4}^{{2 - }}\) ions were experimentally determined: 0.006, 0.0002, and 0.0003, respectively. The value of the activity coefficient of \({\text{NO}}_{{\text{3}}}^{ - }\) ions in seawater with 35‰ salinity was ascertained: 0.533 ± 0.011 at 25°C.

Abstract The algae geochemical anomaly coefficient (KGA) and hazard coefficient (KMe), which are geochemical coefficients characterizing the condition of an algae habitat, have been calculated based on heavy metal (Fe, Mn, Cu, Zn, Pb, Cd, and Ni) levels in the brown alga Sargassum miyabei sampled at different time intervals from 49 stations in Peter the Great and Kievka bays, Sea of Japan. It has been

Abstract—In 2019, a new instrument was included in the multifunctional measuring complex at the Gelendzhik Research Site (Shirshov Institute of Oceanology, Russian Academy of Sciences, IO RAS), which allows automatic measurement of the hydrophysical parameters of the aquatic environment from the bottom layer to the surface of the waterbody with on-line transfer of data to the coastal center. This is

Abstract Joint analysis of wind wave characteristics derived from Voluntary Observing Ships data (VOS) and the third-generation spectral wave model WAVEWATCH III v.5.16 hindcast is presented. Global distributions of significant wave heights and mean periods in both datasets demonstrate good qualitative and quantitative agreement, especially in regions with a high spatiotemporal density of observations

Abstract The present study examined the hydrochemical and biological parameters influencing the spatial distribution of bacterioplankton in the Laptev Sea and the East Siberian Sea shelf regions affected by the Khatanga, Indigirka and Kolyma rivers runoff during September 2017. The highest bacterial abundance and the amount of actively respiring bacteria were determined in rivers delta and in surface

Abstract Statistical analysis of heat flow distribution along nine geotraverses crossing mid-oceanic ridges in the Atlantic, Pacific, and Indian oceans is carried out. Significant asymmetry of heat flow distribution is established: its mean values differ on opposite sides of ridge axes. In geotraverses of the Southern Hemisphere, their western flanks have a higher average heat flow, and on geotraverses

Abstract Studies of the interannual variability of primary production, surface water temperature, photosynthetically active radiation, and sea ice cover in the Laptev Sea were performed based on MODIS-Aqua data (2002–2018). For a 17-year period, a statistically significant positive trend of surface temperature (R2 = 0.27) and a negative trend of photosynthetically active radiation (R2 = 0.24) were

Abstract—Tidal ocean corrections for gravity observation play an important part in monitoring studies. Tidal ocean models were tested by Transcontinental Tidal Gravity Profile (TTGP) results. This part of the global tidal network was used for study the influence of the Atlantic and Pacific oceans up to coastline. Our tidal result agrees with static theory and had a weak ocean dynamic influence (Schiwiderski

Abstract— Materials collected in different seasons in the region of the Yenisei estuary, as well as previously published data, were used to analyze the scale and patterns of the seasonal variability of microbial communities. In all seasons concerned, three zones could be distinguished in the estuarine area based on the salinity values. The abundance and activity of bacterioplankton in these zones varied

Abstract— Based on average monthly data of the ORAS4 ocean reanalysis, the spatial distribution and values of anomalies of the ocean surface temperature and the velocity of surface currents occurring in the North Atlantic at the meridional displacements of the north wall of the Gulf Stream in January–February are determined. Gulf Stream North Wall Index data are used as data on Gulf Stream movements

Abstract—The results of acoustic sounding of the routes of underwater pipelines obtained by the authors in a number of expeditions in river water areas and in the seas of the Arctic Ocean are considered. The possibilities of using narrow-beam parametric systems as a component of environmental monitoring are discussed. in areas buried under the bottom of underwater pipelines.

Abstract It is considered that changes of the North Atlantic’s heat content can be a source of surprises in the evolution of the present-day climate, especially the climate of Europe. To investigate this problem, the RAPID monitoring program has been organized. However, results of such monitoring still cover too short a time interval to reach any particular conclusions. In this study, using wavelets

Abstract A time-continuous, spatially discrete motile predator–immobile prey model has been developed to describe the interactions between harpacticoid copepods and benthic microalgae in the intertidal zone. Harpacticoids perform periodic and nondirectional migrations; the local intensity of these migrations is trophic-dependent, related to the ratio of real to maximum food consumption rates. The zero-dimensional

Abstract—Chemical composition of the Upper Pleistocene sediments (turbidites interbedded with hemipelagic sediments) from contact zones with basalt sills in the Guaymas Basin, Gulf of the California (DSDP Hole 481A), was studied by the methods of XRF and ICP-MS. Alteration for most macroelements in these sediments is not or slightly. This is not indicates immobility or slightly mobility of these elements

Abstract The paper presents the results from a study of the population structure of alien snow crabs Chionoecetes opilio in the western Kara Sea near the Kara Strait using two methods: Sigsby trawling and video surveillance. The towed unmanned underwater vehicle Videomodule was used to estimate the population density of crabs: 0.55 ind/m2 in 2016, and 0.17 and 0.09 ind/m2 in 2017. No differences were

Abstract In the winter low-water season in March and the first week of April 2019, comprehensive hydrological and hydrochemical studies were carried out at the mouths of two small rivers of the White Sea catchment basin: (the Mudyuga River, which flows into Dvina Bay, and the Tamitsa River, which flows into Onega Bay). In the nearshore of the first river, microtidal conditions are observed (the size

Abstract The research program of the dynamics and ecosystem of the Drake Passage and Scotia Sea is scientifically substantiated. Measurements will be carried out by the interdepartmental expedition of the Russian Academy of Sciences with the participation of nine institutes aboard the the R/V Akademik Mstislav Keldysh. The research will be based on study of the functioning of the Antarctic marine ecosystem

Abstract Nannofossils were studied, recovered from Late Pliocene–Pleistocene sediments at station 3316 on cruise 46 of the R/V Akademik Ioffe north of the Rio Grande Rise in the Southwest Atlantic. The presence of irregular discoasters in a narrow horizon at the end of the Discoaster brouweri zone of the Upper Pliocene indicates dramatic changes in the living conditions of these organisms, which led

Abstract During cruise 73 of the R/V Professor Gagarinskiy and cruise 53 of the R/V Akademik Oparin, oceanographic studies of the Sea of Japan and Sea of Okhotsk and the Northwest Pacific were carried out. New data were obtained on the seafloor structure, water structure, and slope convection features in the Sea of Japan.

Abstract— For the first time, the species composition of heterotrophic nanoflagellates, their quantitative characteristics, and abundance and biomass of their main food objects—bacteria and picophytoplankton, were determined in the water column and sediments of the Laptev Sea. In early autumn, an increase in the number and biomass of planktonic flagellates was recorded on a meridional transect from

Abstract The species composition, abundance, biomass, and distribution of zooplankton were studied on the shelf and slope of the northwestern Laptev Sea and the shelf of the East Siberian Sea in summer 2015. The trophic status of common zooplankton and fish species, as well as their position in the food webs of these two seas, has been determined based on stable carbon and nitrogen isotope analyses

Abstract Based on long-term data on the spatial distribution and fluxes of streaming (bubbling) methane in the Black Sea, the study considers various types of streaming gas emissions contributing to the methane content in the anoxic zone of the Black Sea. The estimate for the annual influx of methane gas emissions to the methane budget in the Black Sea was 1.2 × 109 m3 or 0.9 Tg, which is significantly

Abstract The article analyzes the author’s own data on the species composition of planktonic foraminifera tests from Upper Cretaceous sediments in the Indian Ocean, as well as from sections of the marginal shelf seas of Australia. Planktonic foraminifera species are grouped and arranged into a climate series. Analysis of the change in the systematic composition of foraminifera made it possible to identify

Abstract Various aspects of the seasonal and interannual variability of the sea ice cover are estimated based on all available Bering Sea ice data from 1960 to 2017. The possibility of long-term and super-long-term modeling of the ice cover is investigated. Test results are given, and a conclusion is drawn on the prospects of the proposed model and possibility of its practical application.

Abstract The diversity, phylogenetic relationships, and demographic history of glacial relict copepod Limnocalanus macrurus from estuaries of large Siberian Arctic rivers (the Ob, Khatanga, Lena, Indigirka, and Kolyma) are studied using mitochondrial cytochrome oxidase subunit I gene (COI mtDNA). It is shown that Siberian populations of Limnocalanus macrurus, together with those from the Canadian Arctic

Abstract The benthic fauna of Oga Bay (Kara Sea, Novaya Zemlya archipelago) was studied in 2015–2016 during the R/V Akademik Mstislav Keldysh expeditions. Five grab stations at depths of 70–140 m were sampled (three grabs per station). Three macrobenthic communities consecutively replacing each other from the inner near-glacier part of the bay toward the outer slope were revealed. Concentration of

Abstract— The article considers a particular event in the influence of a mesoscale cyclone (MC) on the northern Sea of Japan on February 10–11, 2013. The passage of the MC was accompanied by a sharp increase in wind to storm conditions, an almost twofold decrease in total heat transport, and a fourfold increase in the momentum flux. Perturbations of the hydrological characteristics in the wake of the

Abstract The article presents the results of geophysical and geomorphological works on the western shelf of the Crimean Peninsula (Yevpatoriya–Balaklava). The sedimentary sequence structure, seafloor topography, and paleogeographic reconstructions of the formation conditions of the western shelf in the Late Pleistocene–Holocene are considered. Geoacoustic profile analysis aided in identifying the main

Abstract The article discusses the preliminary results of plume and bottom sediment studies of the Trollveggen hydrothermal vent field based on data from cruise 68 of the R/V Akademik Mstislav Keldysh. The hydrothermal vent field is located east of the axial zone of the slow-spreading Mohn Ridge near the Jan Mayen hotspot at a depth of about 550 m (71°18′ N, Norwegian–Greenland Basin). The hydrothermal

Abstract One of the key problems of physical oceanology is the search for effective global mechanisms that can result in formation and sustainability of the oceanic thermohalocline, which accumulates huge amounts of heat in the middle latitudes. The study revealed a genetic relationship between this element of macroscale stratification and the intensity of vertical mixing of waters caused by double

Abstract— Naturalization of the invasive copepod Oithona davisae is examined based on long-term (2003–2014) routine observations of zooplankton in Sevastopol Bay (the Black Sea). The study analyzes inter-annual and seasonal variability of the species and their impact on the native copepod community. The invasion of O. davisae and their undoubted dominance in terms of abundance have been shown to alter

Abstract It is generally accepted that changes in the heat content of the North Atlantic can be a source of some surprises in the present-day climate evolution, especially in Europe. The RAPID program, which monitors this heat content, is used to investigate this problem. However, the results of such monitoring are too short-term for any conclusion. Therefore, we use wavelets to analyze variations

Abstract Barium sulfate solubility in diluted Na2SO4–NaNO3 solutions and seawater of 35‰ salinity at 22°C was studied in experiments. The value obtained for the thermodynamic solubility product of barium sulfate was \(L_{{{\text{BaSO}}_{4}^{0}}}^{0}\) = (7.57 ± 0.87) × 10–11. It was shown that equilibrium concentration of dissolved barium in seawater was 30.7 μg/L and the water mass of the World Ocean

Abstract— Intra-annual variability in methane fluxes at the water–atmosphere boundary was shown for the first time in the water area of the Sea of Okhotsk east of Sakhalin Island. The variability in methane fluxes is determined by the presence and activity of submarine methane sources and is related to seasonal changes in the hydrological and hydrochemical parameters of seawater and current structure

Abstract The bathymetric ranges of the same deep-sea (>2000 m) species in the Sea of Japan and outside it are compared. Among 85 deep-sea species of the Sea of Japan mega- and macrofauna, 26 species are known outside the sea at depths greater than 2000 m and 45 species only from the sublittoral and bathyal zones (<2000 m). The remaining 14 species are endemic to the Sea of Japan. The species of the