Ekaterina A. Ovsepyan

Shirshov Institute of Oceanology

Benthic foraminiferal assemblages were studied in twenty surface sediment samples collected in the western part of the East Siberian Sea in the framework of the expedition of the R/V Ivan Kireev in 2004. Rose Bengal treatment made it possible to separate "living" and dead individuals. Taxonomic analyses reveal that "living" calcareous foraminifers...

Several drifts of different types and sizes are identified near the northern exit of the Vema Channel, within the projects Neogene-Quaternary contourites of the Central and South Atlantic and Lateral sedimentation in the deep ocean (on the examples from the Central and South-Western Atlantic). Herein, we discuss new results of a multidisciplinary s...

On August 6, 2021, the chief researcher of the IO RAS, Doctor of Geological and Mineralogical Sciences, Professor Ivar Oskarovich Murdmaa turned 90 years old. The main focus of I.O. Murdmaa is the study of bottom sediments of seas and oceans, their lithology, mineralogy, deposition processes, facies and formations, the theory of oceanic sedimentoge...

Deglacial dissolved oxygen concentrations were semiquantitatively estimated for intermediate and deep waters in the western Bering Sea using the benthic foraminiferal-based transfer function developed by Tetard et al. (2017), Tetard et al. (2021a). Benthic foraminiferal assemblages were analyzed from two sediment cores, SO201-2-85KL (963 m below se...

In response to modern global warming and climate emergency, large oxygen-depleted oceanic areas, known as Oxygen Minimum Zones (OMZs) have been expanding for the past decades, with negative ecological and economic consequences on food chains, marine ecosystems and resources, biodiversity, and fisheries. The future evolution of these areas and their...

Oxygen minimum zones (OMZs) are oceanic areas largely depleted in dissolved oxygen, nowadays considered in expansion in the face of global warming. To investigate the relationship between OMZ expansion and global climate changes during the late Quaternary, quantitative oxygen reconstructions are needed but are still in their early development. Here...

Oxygen Minimum Zones (OMZs) are oceanic areas largely depleted in dissolved oxygen, nowadays considered in expansion in the face of global warming. Their ecological and economic consequences are being debated. The investigation of past OMZ conditions allows us to better understand biological and physical mechanisms responsible for their variability...

The submarine Shirshov Ridge is an independent system of terrigenous sedimentation, which is geomorphologically isolated from bottom terrigenous influx into the deep-water basin of the Bering Sea. Using the ridge as example, we studied background hemipelagic sedimentation of the finely dispersed terrigenous suspended matter from water column and de...

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the global climate system due to its role in oceanic heat transport, CO2 exchange between the ocean and atmosphere, and carbon storage in the ocean interior. Previous studies have proposed dramatic changes in the global thermohaline circulation during glacial–interglacial...

Our new and previously published data on sea surface bioproductivity changes from different parts of the Pacific Ocean in the Northern Hemisphere were analyzed in relation to meridional overturning circulation during the last deglaciation. Synchronous episodes of upwelling intensification in the Eastern Equatorial Pacific and Southern Ocean cores i...

Геологические исследования в 43-м рейсе НИС “Академик Иоффе” были организованы Геологическим институтом и Институтом океанологии им. П.П. Ширшова РАН. Рейс был совмещен с перегоном судна после завершения арктического туристического сезона в период со 2 по 31 октября 2013 г. (порт выхода – Роттердам, Голландия, порт прибытия – Монтевидео, Уругвай).

The present paper addresses the issue of the existence of inferred hiatus on the Shirshov Ridge in the western Bering Sea, which is represented by a sand layer allegedly produced by intensification of the bottom current at the penultimate glacial/last interglacial boundary. Intensification of current velocity near the ocean floor likely provoked wa...

We present results from the sediment core SO201-2-85KL retrieved from the western Bering Sea that recovered the past 180 000 years. For the first time, the intense dissolution of calcareous microfossils has been established when the Bering Strait was open during the glacioeustatic sea level rise. Possible mechanisms of climatic teleconnections betw...

The lithological analysis of sediments from Core SO201-2-85KL (18 m long) taken from the Shirshov Ridge in the western part of the Bering Sea (57°30.30′ N, 170°24.79′ E, water depth 968 m), which recovered the section spanning from the penultimate glaciation till Holocene, revealed their mostly terrigenous composition with several intercalations of...

The se-�surface bioproductivity changes over the last 25 kyr were inferred from published data on 30 sediment cores from the open Northwest Pacific (NWP), Sea of Okhotsk, Bering Sea and Sea of Japan accounting for the glacioeustatic se-�level changes. A novel method was developed to compare the variations of several independent productivity proxies...

The benthic and planktonic foraminiferal assemblages and the distribution of coarse grain -size factions were studied in the upper 4.5 m of the Core SO201-2-85KL (57°30.30′ N, 170°24.79′ E, water depth 968 m) retrieved from the Shirshov Ridge. This part of the core covers 7.5 to 50 kyr BP. The glacial period is established to be characterized by lo...

Changes in paleoceanographic conditions on Shirshov Ridge, Western Bering Sea, are inferred over the last two glacial cycles from the high-resolution study of planktic and benthic foraminiferal assemblages and IRD from the upper and lower parts of an 18m-long piston core SO201-2-85KL (57°30.30'N, 170°24.79'E, water depth 968 m). Here we present evi...

Environmental changes in the surface and bottom water layers of the Ingøydjupet Basin and the his� tory of the Atlantic Water inflow to the southwestern Barents Sea during the last 16 ka are reconstructed based on planktic and benthic foraminiferal assemblages. The multiproxy study of sediment cores PSh�5159R and PSh�5159N, including AMS 14C dating...

Environmental changes in the surface and bottom water layers of the Ingøydjupet Basin and history of Atlantic water inflow to the southwestern Barents Sea during the last 16 ka are reconstructed on the base of planktic and benthic foraminiferal assemblages. A multiproxy study of sediment cores PSh-5159R and PSh-5159N, including AMS 14C dating, prov...

Five assemblages of benthic foraminifers reflecting the changes in the properties of the intermediate water masses and the biological productivity during different periods of the last glacial-interglacial cycle are defined based on the abundances and relative contents of indicative species in the upper 9 m of giant Core MD02-2529 from the Cocos Rid...

We analyzed n-alkanes spectra, TOC content, and C/N ratio in the upper 12 m of the giant IMAGES Core MD02-2529 from the Cocos Ridge (08°12.33'N; 84°07.32'W; 1619 m w.d.) to estimate terrestrial organic matter (TOM) and marine organic matter (MOM) contribution to the total organic matter budget in sediments. Multi-proxy studies of nannofossils, bent...

The density and vertical distribution of living calcareous foraminifera have been studied in six box cores from the shelf depressions in the Western Barents Sea in relation to total organic carbon content and flux to the seafloor, primary production, sedimentation rates, bottom-water masses and stable isotopes. It appears that at least several infa...