The Dushak-Erekdag survey of roAp stars

The search of roAp stars at Mt. Dushak-Erekdag Observatory was started in 1992 using the 0.8 m Odessa telescope equipped with a two-star high-speed photometer. We have observed more than a dozen stars so far and discovered HD 99563 as roAp star while BD+8087 is suspected to have rapid oscillations. Negative results of our observations for the search of rapid oscillations in four stars in NGC 752 are also discussed.     

Terrigenous Sedimentation on the Submarine Shirshov Ridge (Bering Sea) during the Last Deglaciation

Lithology and Mineral Resources - The submarine Shirshov Ridge is an independent system of terrigenous sedimentation, which is geomorphologically isolated from bottom terrigenous influx into the...     

Sedimentary infill in the equatorial Mid-Oceanic Canyon,Atlantic Ocean

Facts confirming the hypothesis of contourite sediment infill of the Equatorial Mid-Ocean Canyon (EMOC) are presented. We examined two cores recovered in Cruises 37 and 43 of the R/V Akademik Ioffe (2012, 2013). The cores recovered upper Quaternary miopelagic clays on the EMOC floor (AI-3149) and the adjacent abyssal plain (AI-2620). The study of these cores unraveled significant differences in their composition. In contrast to the lithologically homogeneous Core AI-2620, Core AI-3149 includes interlayers enriched in the biogenic CaCO₃, terrigenous silt, and authigenic ferromanganese micronodules. These peculiarities are attributed to activity of the Antarctic Bottom Water (AABW) contour currents along the EMOC.     

Oceanological Research in the Baltic Sea during the 56th Cruise of the Passenger Vessel Akademik Ioffe

Oceanology - During the 56th cruise of the P/V Akademik Ioffe (August 2020) in the Baltic Sea, hypoxia was registered at a water depth of 80 m, hydrogen sulfide in the East Gotland Basin was...     

Paleocurrents in the Charlie-Gibbs Fracture Zone during the Late Quaternary

Planktonic foraminiferal and ice-rafted debris count data, as well as the mean size of mineral particles of the 10–63 μm fraction (sortable silt, \(\overline {SS} \)) were used as a proxy for surface and near-bottom paleocurrent intensity variations. The data obtained support our hypothesis about turbiditic origin of the lower (80–370 cm) section of the studied AMK-4515 core. Stratigraphic subdivision of the upper section (0–80 cm) makes it possible to allocate two marine isotope stages (MIS) covering the last 27 ka. The main intervals of the North Atlantic Polar Front (PF) migrations were recorded: south of the modern PF position during early MIS 2 (24–27 ka) with PF presence in the study area during MIS 2 (20–24 ka); south of the study area during the last glacial maximum (18–20 ka). Influence of the near-bottom currents within the investigated interval led to beginning of the channel-related drift formation on the northern slope of the southern channel of the Charlie-Gibbs Fracture Zone. There is a weak relationship between intensity of near-bottom contour currents and long-term climatic cyclicity. However, intervals corresponding to Heinrich events coincide with decrease in bottom currents activity.     

Integrated Oceanographic Research of Discovery Gap (Eastern North Atlantic) during the Cruise 43 of the R/V Akademik Nikolaj Strakhov

Oceanology - 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...     

Bioindication of the environmental state of marine areas with the use of fish biomarkers

The study is focused on the effect of the concentrations of toxic elements Zn, Cu, As, Pb, Hg, and Cd in the muscles of six species of Black-Sea fish on the concentrations of modified forms of proteins and medium-molecular peptides in fish serum. Correlation analysis established that the effect of toxic elements on the concentration of modified forms of proteins decreases in the series Zn + Pb > As > Hg > Cu > Cd and that for medium-molecular peptides decrease in the series Pb > Cu > Zn > Hg > As + Cd. The possible use of the concentration of modified forms of proteins and medium-molecular peptides in fish blood as biomarkers for assessing their state and the effect of habitat on them.