卷 63, 编号 1 (2023)

The paper proposes a study of the transformation of the physical properties of mesoscale vortices during their strong elongation by horizontal barotropic currents. It is shown that when the core is pulled out, the kinetic and available potential energies of the vortex individually, as well as their sum (the total mechanical energy of the vortex) decreases, and the vortex itself degrades in all physical parameters. The decrease in the energy of the ensemble of vortices when they are pulled out by the background flow is interpreted as a manifestation of the reverse energy cascade property or, in older terminology, the phenomenon of negative viscosity.

The paper presents the results of autumn-winter surveys of the thermohaline structure and currents of the Tag-anrog Bay of the Azov Sea in 2021. The seiche periods of the sea proper are estimated from the results of spectral analysis of data from Temryuk level detectors. A comparison was made with the spectra of level fluctuations in Yeisk and Donskoy. The conclusion is made about the predominance of cyclically repeating seiche currents over wind currents. The eigen resonance mode (uninodal seiche) in the eastern part of the Taganrog Bay has a period of 12 h, in the central and western parts - 24 h, in the Azov Sea proper - 38 h. Estimates are confirmed analytically, by current measurements and by level detectors. In practice, this means that with the strongest positive and negative water setups in 12-24 hours, with a constant wind, the direction of the current will change to the opposite. The described nature of the circulation, on the one hand, distinguishes the Azov Sea from other similar water bodies, on the other hand, it makes it possible to reveal the energy potential of the basin in an unusual way.

The inconstancy of phytopigment composition during intensive mesoscale mixing of the Tasman Sea photic layer was investigated using MODIS images of its surface. To do this, each pixel of such an image is assigned a WRM index equal to the sum of the wavelengths of the minima in the reflectance spectrum of the water surface within the boundaries of a pixel on the ground (Spectral Indexing of Pixels, or SIP approach). WRM is acceptable as an indicator of phytopigment composition variability in the water column, since the attenuation of light by water as a solvent and by its admixtures of other nature is inferior to light absorption by phytopigments in spectral selectivity, while the composition of phytopigments in the aquatic environment depends on the species composition of local phytoplankton. A co-analysis of WRM distributions and characteristics of Tasman Sea waters showed that with increased mesoscale variability in open ocean waters, phytopigment content in the near-surface layer reaches levels at which minimums of pigment origin at 400–550 nm, discernible by multispectral ocean color scanners, occur in the backscattered solar radiation spectrum. This phenomenon is ignored by common algorithms for chlorophyll determination based on the data of multispectral ocean color scanners (band-ratio algorithms) and, apparently, is one of the reasons for the known tendency of such algorithms to overestimate chlorophyll concentration relative to its real content in the water column. The conclusion is applicable to any ocean basins if they, like the Tasman Sea, are not affected by external sources of optically significant admixtures in water.

Hydrobiological surveys (plankton and benthos, including snow crab) were carried out in the summer of 2003–2020 in the south-western region of the Chukchi Sea. At the west, east, and north edges of C. opilio distribution area in the Chukchi Sea the amounts of the crabs were 5–10 times lower due to the limit of species’ tolerance to hydrological factors and inappropriate trophic base – low mass of zoobenthos. Some gatherings of snow crab C. opilio in northern regions of the Chukchi and the East-Siberian Seas can be considered as dependent, which depends on income from southern regions of the Chukchi Sea. The southern regions of the Chukchi Sea are some kinds of the nursery for development and growth of snow crab larvae and youth until 1–2 years age, from where they migrate into northern deeper regions of the Chukchi Sea, and then more fare into north-eastern region of the East-Siberian Sea.

Based on the materials of 20 expeditions of the IO RAS conducted in various areas of the coastal zone of the Russian sector of the Black Sea in the period from 1999 to 2021, empirical equations the relationship between the relative transparency (depth of visibility of the white disk Zd) and the mass concentrations of the total suspended matter-SM and its mineral – SMM and organic – POM fractions (Csm, Csmm and Csom, respectively) were obtained. The values of Zd were recorded in the range from 0.1 to 21 m, the concentrations of SMM – from 0.11 to 104 mg/L, POM – from 0.09 to 2.0 mg/l and chlorophyll a (Ca) – from 0.03 to 4.4 mcg/l. The relative abundance of the POM in the suspension ranged from 1.1 to 48.7%. The estimation of the error in the calculations according to these equations is carried out. The coefficients of determination r² = 0.85 (for lgCsm and lgCsmm ) and 0.72 ( for lg Csom). The influence of the concentration of POM – on the accuracy of the calculation of Csmm and the concentration of chlorophyll a on the accuracy of the calculation of Csom was revealed. It is concluded that it is possible to use empirical formulas related to the entire array to calculate the concentrations of these fractions of suspension in the entire studied water area. It is proposed to consider the method of estimating the content of suspension fractions based on the obtained empirical equations as a regional variant of the method of passive sounding of the upper layer of the sea using a white disk.

The article systematizes and summarizes published data on the parameters and distribution areas of modern and relict iceberg scours (or plough marks), as well as on the maximum possible sizes and drift areas of modern icebergs in the Barents and Kara Seas. According to the open-source bathymetric data, for the first time the analysis of “throughput” of the waters in front of modern glaciers was carried out. Based on summarized and established facts, areas of the most likely distribution of modern iceberg effects on the bottom are determined by the method of expert assessment. This work is relevant both from a fundamental point of view and for determining the current depths limits of iceberg scouring at the bottom of the Barents and Kara Seas, which is important for ensuring the geoecological safety of all kinds of activities on the sea shelf.

During the 41th scientific cruise of the R/V “Professor Logachev” in 2019, two new ore fields were discovered within the Russian exploration area of the Mid-Atlantic Ridge. The “Korallovoye” ore field is located in the middle part of the rift valley ridge and lies on a gentle slope in the depth range of 2800–2850 m. The “Molodezhnoye” ore field is located at a distance of approximately 5 km northeast of the “Korallovoye” field and lies on a less steeper section of the slope between 3500 and 3550 m in depth. The “Korallovoye” and “Molodezhnoye” fields are confined to the outcrop of a gabbro-peridotite massif on the western side of the Mid-Atlantic Rift valley. The total number of discovered ore fields in the Russian exploration area has been increased to 14 sites.

A seismogenic-trigger mechanism is proposed for the rapid activation of the destruction of cover and shelf glaciers in West Antarctica at the end of the 20th and the beginning of the 21st centuries, accompanied by the release of methane from the underlying hydrate-bearing sedimentary rocks and consequent rapid climate warming. This mechanism is associated with the action of deformation waves in the lithosphere-asthenosphere system, resulting from the strongest earthquakes occurring in the subduction zones surrounding Antarctica – Chile and Kermadec-Macquarie. Disturbances in the lithosphere are transmitted over long distances of the order of 3000 km, and the additional stresses associated with them, which come to Antarctica several decades after earthquakes, lead to a decrease in the adhesion of glaciers to underlying rocks, accelerated sliding of glaciers and the development of faults in them. This process, in turn, results in a reduction of pressure on the underlying sedimentary layers containing gas hydrates, which lead to methane emission and climate warming. The considered hypothesis leads to the conclusion that in the coming decades the processes of destruction of glaciers and climate warming in Antarctica will speed-up due to an unprecedented increase in the number of strongest earthquakes in the subduction zones of the South Pacific Ocean in the late 20th and early 21st centuries.

Organic carbon of fecal pellets and small-sized (≤ 1mm) zooplankton was measured using a high- temperature combustion method. The method was adapted for measurements with Shimadzu TOC-VCPH analyzer equipped with a manual injection module. The range of carbon content values was 30–10 000 ng ind^–1. The samples for analysis were collected during the cruises of the R/V “Akademik Mstislav Keldysh”in the Kara Sea in 2019-2021. Relationship between body carbon (C, µg ind^-1) and prosome length (L, mm) of zooplankton describes by the equation С = 4.24 L^1.84, r² = 0.85, n = 46. Carbon of field collected fecal pellet varied from 9.4 до 102.9 µg С mm^–3. The carbon to chlorophyll a ratio of fecal pellets differed by more than two orders of magnitude. The highest values (542 and 736) were obtained in the bays of the Novaya Zemlya archipelago, the lowest (3–6) on the Kara sea shelf in June 2021 soon after ice melting. The perspectives of implication of high temperature combustion method for studies of zooplankton in situ feeding and to estimate the contribution made by pellets to POC vertical flux are discussed.