Particle trajectories and average settling and drift velocities of microplastic particles under wave action were studied in a linear wind-wave channel. A wave-maker and an airflow above the water surface created various hydrodynamic conditions. Particles of various shapes (isometric, flat, elongated) were used. The paper provides a brief overview of the theoretical approaches (dimensional analysis) used to study the transport of microplastics in the presence of surface waves and currents. Based on this, a characteristic of wave regimes and sets of experimental particles is given. Terminal settling velocities of the particles in a quiet fluid are 1.0–3.8 cm/s. They were obtained experimentally and may be of independent interest. The settling trajectories of 13 types of particles in 4 wave regimes were obtained and analyzed. According to Welch’s t-criterion (p < 0.05), the average particle settling rate in the presence of waves differs slightly from the terminal settling velocity, which is consistent with other works. The results indicate that the average horizontal (drift) velocity follows the velocity of the mean current. The presence of wind enhances horizontal transport due to the induction of drift current and drastically increases particle dispersion.

The allelic diversity of the DQB gene of the major histocompatibility complex (MHC) in the Atlantic walrus from the European part of the Arctic was analyzed for the first time. We studied animals from the haulouts located on the Franz Josef Land archipelago and near the northern tip of Novaya Zemlya. We demonstrated that there are significant differences for this locus between the two studied haulouts. Simultaneous analysis of microsatellite loci reveals a lower level of differentiation and also suggested that animals from more than one spatial-geographical stock (population) gather at the summer haulout on Novaya Zemlya. It has been suggested that individuals with different MHC genotypes may prefer different feeding areas, regardless of the areas of residence during the breeding season.

We analyzed population genetic structure of polar bear (Ursus maritimus) in the Russian Arctic based on samples collected in 2010–2021. For 93 adult individuals, we report polymorphism of 17 nuclear DNA microsatellite loci and a 610 nucleotide long mtDNA D-loop fragment. High genetic diversity of nuclear DNA and low nucleotide diversity π for mitochondrial DNA was found. All genetic markers proved differentiation between bears of southern Barents Sea and northern Barents and Kara seas. These two groups differed by distribution of the mitochondrial marker (θst = 0.270) and, to less extent, by nuclear loci (Rst = 0.018).

The Polar bear's seropositivity from the Barents Sea subpopulation to a number of pathogens was analyzed: Canine distemper virus, Herpes simplex virus, Parvovirus, Toxoplasma, Trichinella (Trichinella sp.), Mycoplasma (Mycoplasma sp.), Candida (Candida sp.) and Chlamydia (Chlamydia sp.). Seropositive animals have been identified for Canine distemper virus and Trichinella (Trichinella sp.). The proportion of seropositive animals to Trichinella was the maximal. Over the last 10 years, an increased share of animals seropositive to Trichinella and Canine distemper virus has been noted in the study area.

The seabed topography of the Velikaya Salma Strait of Kandalaksha Gulf, White Sea, was studied using multibeam echo sounding, side-scan sonar surveys, seismoacoustic profiling, geological sampling, and survey from remote-operated underwater vehicles. A digital elevation model of the seabed with a grid cell of 2 m, slope angle map and exposure map were created. Structural-denudation, glacial, gravity, and tidal-current of meso- and microrelief forms were identified on the seabed of the strait. An approach to large-scale geomorphological mapping was proposed, based on identification of morphogenetic complexes: regular combinations of meso- and microrelief forms typical of glaciated shelves. The boundaries of morphogenetic complexes are repeat by the methods for automated analysis of morphometric parameters calculated using TIN models. This approach can be used for landscape and engineering-geological mapping, including identification areas of geological hazards.

Настоящая работа посвящена разработке и применению системы измерения полей скорости течения методом Particle Image Velocimetry (PIV) (Анемометрии по Изображениям Частиц) в исследованиях турбулентного пограничного слоя в модернизированном гидродинамическом лотке Атлантического отделения Института океанологии им. П.П. Ширшова Российской академии наук. Работы проводились в рамках подготовки лабораторной установки к экспериментам по взмучиванию частиц микропластика со дна, покрытого естественным донным осадком. Эксперименты выполнялись при трех типах покрытия дна: крупный песок (1—1.5 мм), зёрна янтаря (3—4 мм), галька (1—2 см). Разработанная система PIV-измерений базируется на использовании цифровой камеры средней производительности и непрерывной лазерной подсветки. Эксперименты выполнялись в широком диапазоне скоростей потока (до 2 м/с), задаваемых частотой вращения насоса и положением регулирующей заслонки. Выполнены измерения профилей средней скорости, по наклону логарифмической части которых вычислялась динамическая скорость, которая, вместе с масштабом шероховатости дна, является одной из основных характеристик при исследовании процессов седиментации/взмучивания. Динамические скорости для песка и янтаря оказались близкими друг к другу, и значительно меньше, чем для гальки. Масштаб шероховатости для гальки, как и ожидалось, оказался максимальным. Янтарь в экспериментах не только моделировал дно промежуточной шероховатости, но также, из-за своей относительно малой плотности (1.07 г/см), позволил наблюдать начало движения частиц при небольших скоростях потока — меньших, чем необходимо для начала движения песка. Сравнение результатов наблюдений с известными данными А. Шильдса о пороге взмучивания янтаря показывают их хорошее согласие. Одним из основных преимуществ PIV-измерений в последующих экспериментах по исследованию динамики МП, можно считать возможность практически мгновенного измерения характеристик течения в пограничном слое с одновременным отслеживанием динамики добавленных на поверхность дна частиц МП.

The Velikaya Salma Strait is part of a fiard, typical of the Kandalaksha Gulf of the White Sea. Seabed topography, landscapes, and bottom sediments were studied in an area of 35.12 km(2) (depths of 10-120 m) using geophysical methods, geological sampling, and visual observations. Macrobenthos distribution was sampled at 15-60 m depth and studied using an underwater camera. Structural-denudation, glacial, gravity, and tidal current landforms were identified on the Strait seabed. Bottom sediments vary from boulder-pebble to pelite. The bathymetric zonation of their distribution is disturbed when tidal currents encounter the dissected seabed topography and by gravitational displacements. Macrobenthos distribution has statistically significant dependence on bottom sediments grain size and depths. Galathowenia oculata-Chaetozone setosa community prevails on muddy sediment, and Macoma calcarea-Scoloplos acutus community prevails on sandy bottom. Statistical relationships between sidescan sonar images and macrobenthos distribution are stable in the areas of gently dismembered seabed and are lost in the areas of dissected topography.

Структура и внутренняя динамика интрузионного течения изучалась при помощи двумерной численной модели стратифицированных по плотности течений в вертикальной плоскости. Течение в модельном пространстве формировалось за счет притока жидкости промежуточной плотности в двухслойную среду. Приток осуществлялся в виде двух импульсов фиксированного объема с заданным интервалом времени между ними. Начальная стратификация определялась перепадом плотности между слоями равной толщины и толщиной промежуточного слоя. Для идентификации водных масс отдельных импульсов в расчетах использовались индивидуальные поля пассивной примеси. Предложен набор безразмерных параметров, определяющих начальные и граничные условия задачи. Численные эксперименты показали существенное влияние пульсаций расхода источника на эволюцию интрузионного течения. В зависимости от параметров затока может происходить как ускорение, так и замедление горизонтального распространения объема второй интрузии. Приведены примеры различной динамики объема второго импульса при закритических и докритических начальных числах Фруда. Расчеты показывают, что импульсный характер источника в наибольшей степени модифицирует течение при коротком интервале времени между импульсами.

The transition from winter vertical mixing to the formation of the spring thermocline in the southeastern Baltic Sea is studied based on data from the hydrophysical measurements program (11 expeditions) in the Russian part of Gdansk Bay in March–June 2010, 2011, and 2013. CTD measurements were taken along the standard 18-km transect across the isobaths with a 500-m step abeam the city of Baltiysk. A set of frequently measured data was collected in a 1–2 week interval from the end of March to the beginning of May, which made it possible to analyze the transformation of the vertical thermal structure of water from inverse winter type to the summer stratification with the transition of temperature over the temperature of the density maximum. Series of repeated measurements at the deep and coastal stations as well as surface and subsurface towed measurements were carried out. The fact that lenses of freshened warmer water appear at the surface almost simultaneously with intensification of cold intrusions in intermediate (10–40 m) layers makes it possible not only to confirm the advective nature of the formation of the spring thermocline in the Baltic Sea, but also to hypothesize about the intensification of intrabasin exchange when winter-time vertical mixing ceases: the potential energy excess supported by vertical mixing in the 60-m upper quasi-homogeneous layer (UQL) of the Baltic Proper, in which the horizontal estuarine salinity gradient is significant, is converted to kinetic energy of exchange currents as the mixing process terminates. Such water dynamics makes it possible to explain the intensification of intrusions in the Baltic in spring and the formation of the cold intermediate layer due to the fast propagation of late-winter UQL water from the Bornholm Basin to the Baltic Proper. The results agree well with earlier published studies of other authors.

The size structure of the population, morphology of the reproductive system, and gonad maturation of the chaetognath Eukrohnia hamata (Möbius, 1875) (Chaetognatha) were studied for the first time from zooplankton samples collected in Fram Strait and the deep Eurasian basin of the Arctic Ocean north of the Kara and Laptev seas in the summers of 1995 and 1997. We describe the gonad morphology and the progress of gonad maturation in male and female specimens and propose a system for classification of gonad maturity stages. During the Arctic summer, the population was represented by individuals ranging in size from 2 to 37 mm. The newly hatched young (2.0–3.5 mm long) and juveniles (4.0–12.5 mm long) dominated numerically (30 and 50% of the population, respectively). Our results indicate that E. hamata successfully matures and reproduces in the Arctic basin, but mature individuals make up less than 1% of the population in the summer against the background of juvenile abundance.

The degree of development and operability of the indicators for the Marine Strategy Framework Directive (MSFD) using Descriptor 1 (D1) Biological Diversity was assessed. To this end, an overview of the relevance and degree of operability of the underlying parameters across 20 European countries was compiled by analysing national directives, legislation, regulations, and publicly available reports. Marked differences were found between countries in the degree of ecological relevance as well as in the degree of implementation and operability of the parameters chosen to indicate biological diversity. The best scoring EU countries were France, Germany, Greece and Spain, while the worst scoring countries were Italy and Slovenia. No country achieved maximum scores for the implementation of MSFD D1. The non-EU countries Norway and Turkey score as highly as the top-scoring EU countries. On the positive side, the chosen parameters for D1 indicators were generally identified as being an ecologically relevant reflection of Biological Diversity. On the negative side however, less than half of the chosen parameters are currently operational. It appears that at a pan-European level, no consistent and harmonized approach currently exists for the description and assessment of marine biological diversity. The implementation of the MSFD Descriptor 1 for Europe as a whole can therefore at best be marked as moderately successful.

During 2009-2012 stocks of the bivalve Arctica islandica (Linnaeus, 1767) (Ocean quahog) in Kandalaksha Bay (the White Sea) has been assessed using a side-scan sonar, grab sampling and underwater photo imaging. Structurally uniform localities were highlighted on the basis of side-scan signal. Each type of a signal reflects combination of sediment type, microtopography and structural characteristics of benthic community. The distribution of A. islandica was the predominant factor in determining community structure. Seabed attributes considered most significant were defined for each type of substrate type. Relations of sonar signal and sediment type were used for landscape mapping based on sonar data. Community characteristics at known localities were reliably interpolated to the area of survey using statistical processing of geophysical data. A method of integrated sonar and sampling data interpretation for high-resolution mapping of A. islandica by biomass groups, benthic faunal groups and associated habitats was developed.

Planning of soil dumping, dredging, mining, construction of port facilities and dams and other marine engineering works requires description and subsequent monitoring of benthic communities. According to Russian normative documents when carrying out marine engineering- ecological surveys it is necessary to construct theme maps containing information on distribution of marine biota (in particular macrobenthos) and its vulnerability to the main kinds of anthropogenic factors. Benthos research is especially important in connection with inevitable structural damage and redeposition of bottom sediments during pipeline laying. This article reviews current estimation methods of the state of benthic communities (methods of benthic habitat mapping). It also describes research results of benthic community mapping i.e. identification of spatial mosaic elements in several bays in the Peter the Great Bay (the Sea of Japan) revealed by a side-scanning sonar. Especial attention is paid to the necessity of construction of integrated maps of natural ecosystems sensitivity and to application of remote sensing methods (underwater video filming) for investigation of the bottom areas where the most significant influence on the macrobenthos is expected.

The age structure of a dense settlement of Arctica islandica (Bivalvia) near Vysokii Island (Rugozerskaya Guba (bay)) of the White Sea is described. The data collected by trawling in 2003, 2006–2007 and grab sampling in 2009–2011 are summarized. The A. islandica community in the Rugozerskaya Guba was first described in 1953–1959, but to date, no reliable quantitative estimates have been obtained and the community’s size structure was not studied. The size structure of this community was stable over the last eight years; the main part of the community was represented by individuals with a body weight of 3–10 g. It was revealed that the distribution of different A. islandica classes depends on the depth. The majority of the largest individuals were found in the shallowest parts of the study area (9–11 m); middle-size individuals were registered at depths of 9–14 m; and the smallest ones, at depths of 12–17 m.

The age structure of a dense assemblage of Arctica islandica (Bivalvia) is analyzed at the Vysokii Is and (Rugozersky Bay, the White Sea). The data collected during the trawling of 2003, 2006-2007 and grab sampling in 2009-2011 are summarized. The A. islandica community in the Rugozersky Bay was first described in 1953, 1959, but up to date, reliable quantitative estimates have not been obtained, and its size structure was not studied. The size structure of this community was stable during the last 8 years; the main parr of the,assemblage was presented by individuals with a mass of 3-10 g. The dependence of the distribution of different A. islandica classes on the depth was revealed. The majority of the largest individuals was found in the shallowest parts of the polygon; middle-size individuals were registered at depths of 9-14 m, the smallest ones, at depths of 12-17 m.

Abstract Nowadays problems of ecological and geotechnical investigations are emphasized on. A lot of scientists both mapping bottom sediments and trying to reconstruct complex, multi-component seabed system, which include biological factors either. For example, geophysical data is successfully used to evaluate contrasting biological objects on the bottom, such as communities associated with seamounts and pock-marks, oyster or mussels banks. Material for this study was procured during surveys in Kandalaksha bay, the White Sea (Arctic). During 2010 – 2012 side-scan sonar (SSS) and VHR seismic surveys, qualitative sampling, underwater photo and video were carried out at the polygon of study. Main task of this research was community mapping. Spatial structure of benthic communities shows very high heterogeneity in the area of survey. Thus so, samples can’t be validly interpolated to the area more than 20 m in radius. Knowledge of bottom sediment structure and topography allows obtaining a higher degree of accuracy of community mapping. Biodiversity is related to bottom sediments type. It’s mean sonar data include information about community. On the other hand, Arctica Islandica shell big (4 cm on the average) and hard enough to backscatter high-frequency acoustic signal. There are two factors which connect community structure and side scan sonar data, this correlation may be defined. Sediments mapping was done by joint interpretation of the seismic, SSS, data of sample grain size and underwater observations. For research of underwater landscape distribution on the polygon method of mapping was used. It’s based on integrated interpretation of traditional sampling data, underwater observation, photo and video results and remote sensing methods (side scan sonar). Detailed data of underwater landscapes were produced.