Peculiarities of the rare-earth element distribution in the modern bottom sediments of the White Sea and the lower reaches of the Severnaya Dvina River

The study of the rare-earth element (REE) systematics in the modern bottom sediments of the White Sea and the lower reaches of the Severnaya Dvina River showed that they were derived by the simple mixing of the detrital material from two geochemically contrasting provenances: the Kola-Karelian geoblock almost completely consisting of Archean rocks and the northwestern Mezen syneclise made up of the Upper Vendian, Paleozoic, and Mesozoic rocks. This is best manifested by the changes in ?_Nd(0). In terms of the Gd_N/Yb_N and Eu/Eu*, most of the studied samples are comparable with the Post-Archean craton complexes, some of which resemble the average composition of the Archean mudstone. Based on the ΣREE and La_N/Yb_N, the modern bottom sediments are subdivided into two groups: (1) those close to basalts and granites and (2) those approximating common sedimentary rocks. From the lower reaches of the Pinega River to the Tersky coast, the maximal average (La/Yb)_RPSC, (Gd/Yb)_RPSC, La_N/Yb_N, and Gd_N/Yb_N ratios were determined in the samples taken at the boundary of Dvina Bay with the Basin, i.e., in the sediments with the highest content of the pelitic component. In general, the geochemical composition of the modern bottom sediments of almost the entire White Sea area was defined by input of the eroded products of the mature continental crust with the Severnaya Dvina River, the main river of the region. Such a setting, when the formation of the sediments in a peri- or intracontinental marine basin is controlled by one large river system, presumably may be propagated to the sedimentation in the Laptev Sea, the eastern Kara Sea, the Bay of Bengal, and other basins.     

Variations in the concentration of mesospheric ozone during the total solar eclipse of March 29, 2006, from microwave radiometric data

We present the results of microwave observations of the ozone content variability in the upper stratosphere and lower mesosphere during a total solar eclipse of March 29, 2006 at the Kislovodsk high-altitude scientific station. An increase in the concentration of mesospheric ozone was recorded during the eclipse. At a height of 60 km, the ozone concentration increased by 40%, which is close to the value of diurnal ozone variations.     

Concentration and Diffusion of Nutrients in the Interpore–Bottom Water System of the Ob River Estuary

Oceanology - 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...     

Integrated Geological–Geophysical and Oceanographic Research in the South China Sea: Cruise 88 of the R/V “Akademik M.A. Lavrentyev”

Oceanology - 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...     

Effects of Cystoseira Sensu lato (Fucales: Phaeophyceae) on Species Richness,Composition, and Biomass of Abrau Peninsula Shelf Macrophytobenthic Communities (Black Sea)

Oceanology - Field observations were applied to study the macrophytobenthos of the Abrau Peninsula of the Black Sea and the effect of the two most common and largest species of brown algae of the...     

Field Research in the Baltic Sea on Cruise 55 of the P/V Akademik Ioffe

Oceanology - New data on the structure of the water column, upper layer of bottom sediments, and biological communities of the Gdansk and Gotland deeps and the Gulf of Finland in the Baltic Sea...     

Underwater Acoustic Communications Using Vertical Receiver Arrays in Ice-Covered Shallow-Water Areas

Oceanology - The feasibility of underwater acoustic communications in an ice-covered shallow-water area is demonstrated in a field experiment and by computer modeling. The advantages of vertical...     

Vertical Variability of Primary Production and Chlorophyll a in the Kara Sea in the Middle of Summer: Contribution of Subsurface Maxima to the Water Column Values

Oceanology - Spatial and vertical variability of primary production (PP) and Chl a were studied in the framework of the 76th cruise of R/V Akademik Mstislav Keldysh to the Kara Sea from July 7 to...     

Phytoplankton of the Barents Sea at the Polar Front in Spring

Oceanology - This paper describes the comprehensive studies of phytoplankton carried out in April 2018 in the northwestern Barents Sea, in the Polar Front region (74.8°–76.2° N), at...     

Effect of the East Siberian Current on Water Exchange in the Bering Strait Based on Satellite Altimetry Measurements

Oceanology - The seasonal and interannual variability of water exchange in the Bering Strait and its relationship with Arctic circulation is investigated on the basis of satellite-altimetry...