The digital elevation model (DEM) of the Kara Sea bottom was created on the basis of multiscale navigation charts from the Department of Navigation and Oceanography of the Ministry of Defense of the ...Russian Federation. The errors in the created DEM and publicly available IBCAO v3 DEM were calculated using data obtained during expeditions from 2007 to 2022 in the Kara Sea. The accuracy of these two DEMs was assessed using descriptive statistical methods, demonstrating significantly better seabed relief detail in the created DEM.
Abstract
The Kara and Laptev seas receive about one half of total freshwater runoff to the Arctic Ocean from the Ob, Yenisei, and Lena rivers. Discharges of these large rivers form freshened surface ...water masses over wide areas in these seas. These water masses, i.e., the Ob-Yenisei and Lena river plumes, generate an eastward buoyancy boundary current that accounts for the large-scale zonal freshwater transport along the Siberian part in the Arctic Ocean. In this study we investigate spreading of the Ob-Yenisei plume from the Kara Sea to the Laptev Sea through the Vilkitsky Strait and of the Lena plume from the Laptev Sea to the East-Siberian Sea through the Laptev and Sannikov straits during ice-free season. Large horizontal density gradient between freshened plume water and salty ambient sea water is the main driver of these processes, however, their intensity strongly depends on local wind forcing. The Ob-Yenisei plume is spreading to the Laptev Sea in a narrow alongshore current which is induced by strong and long-term southwesterly winds. Under other wind forcing the plume does not reach the Vilkitsky Strait. The Lena plume is almost constantly spreading to the East-Siberian Sea as a large-scale surface water mass which intensity is governed by eastward Ekman transport and is prone to large synoptic variability.
During cruise 81 of the R/V
Akademik Mstislav Keldysh
comprehensive studies of the Kara Sea were carried out over sill separating the central spur of the St. Anna Trough and the Novaya Zemlya ...depression. For the first time, the water exchange parameters between the shelf southwestern and deep northern parts of the Kara Sea have been evaluated. The meridional component of the geostrophic current velocity calculated from CTD data was used to identify both the northern and southern jets reaching the bottom. Two southern streams are responsible for water transfer from the deep-water part of the Kara Sea to the shelf zone. In the eastern part of the transect, transfer of river-runoff-freshened waters to the deep-water area of the Kara Sea was noted.
Microbial communities of the Arctic Ocean are poorly described in comparison to aquatic environments of other regions regarding their patterns of distribution and change. The present work aims to ...investigate free-living bacterial communities (size fraction 0.22–1.5 μm) of different Arctic seas regions, from the river discharge area to the continental slope. Illumina MiSeq metabarcoding analysis using V3–V4 region of 16S rRNA gene was employed to study the microbial diversity of 11 Arctic seawater samples, collected from the surface and near-bottom layers in the Kara and Laptev Seas in August–September 2018. Additionally, we determined environmental parameters, bacterial abundance, biomass, and respiratory activity. Redundancy analysis, Spearman’s rank correlation, and multiple linear regression analysis were used to reveal environmental factors that modulate the bacterial community structure. The differences in the free-living bacterial community composition were associated with environmental characteristics of water layers (salinity and temperature) rather than with geographical area. Although the communities from all examined sites were dominated by
Gammaproteobacteria
and
Alphaproteobacteria
followed by
Flavobacteriia
and
Actinobacteria
, they showed distinct variations in the distribution at all taxonomical levels. No archaeal taxa were observed. The distribution patterns of the quantitative parameters of total bacterial community were not associated with defined environmental characteristics.
By simulating the effect of interfering shear waves on a ferroelectric through a layer of a liquid electrode, it was shown that it is possible to form not only micro-, but also submicron domain ...structures at frequencies below 1000 MHz at room temperature. The frequency dependences of the domain structure period and the angles of incidence of shear waves are obtained for frequencies limited by the framework of the Newtonian fluid model. The method has a short technological cycle, provides the necessary depth of domain inversion, and does not depend on the degree of acoustic transparency.
The article summarizes data on the suspended particulate matter content and dissolved and particulate organic carbon concentrations in Kara Sea water for 2007–2022. A difference in the distributions ...of dissolved (DOC) and particulate (POC) organic carbon in the water column during autumn (September) and spring–summer (July–August) was revealed. An increase in dissolved organic carbon concentrations was recorded both on the surface and in the water column in summer. Analysis of the dependences of DOC concentrations on salinity showed that the increase in these concentrations is not associated with an increase in DOC concentrations in river runoff water. There was also a significant increase in DOC and POC concentrations in phytoplankton bloom zones throughout the water column. Thus, a relationship has been identified between seasonal increases in organic matter concentrations in the open part of the sea and phytoplankton bloom processes.
A technique for the formation of ferroelectric regular domain structures using interfering ultrasonic waves, a uniform electric field, and liquid electrodes based on ionic liquids has been proposed. ...The technique has a short duration of the technological cycle and provides the necessary depth of domain inversion. Based on the simulation results, recommendations are given for choosing the type of ionic liquid and the main parameters of ultrasonic pulses. The results are applicable to ferroelectrics, such as LiNbO
3
, KTiOPO
4
, and PZT.
Internal tide in the Kara Gates Strait Morozov, E. G.; Kozlov, I. E.; Shchuka, S. A. ...
Oceanology (Washington. 1965),
2017/1, Letnik:
57, Številka:
1
Journal Article
Recenzirano
We observed strong internal tidal waves in the Kara Gates Strait. Internal tides are superimposed over a system of mean currents from the Barents to the Kara Sea. Field studies of internal tides in ...the Kara Gates were performed in 1997, 2007, and 2015. In 2015, we analyzed data from towed CTD measurements, numerical model calculations, and satellite images in the region. An internal tidal wave with a period of 12.4 h is generated due to the interaction between the currents of the barotropic tide and the bottom relief on the slopes of a ridge that crosses the strait from Novaya Zemlya to the continent. The depths of the ridge crest are 30–40 m. A constant current of relatively warm water flows from the Barents to the Kara Sea. An internal wave propagates in both directions from the ridge. In the Barents Sea, internal waves are intensified by the current from the Barents to the Kara Sea. Internal bores followed by a packet of short-period internal waves are found in both directions from the strait. Satellite images show that short-period internal waves are generated after the internal bore. A hydraulic jump was found on the eastern side of the strait. Numerical modeling agrees with the experimental results.
Analysis of the distribution of abundance and activity of bacterioplankton in the estuary area of the Ob River in July 2016 and September 2013, as well as environmental factors, made it possible to ...distinguish between riverine, brackish water, and marine zones. In summer, the abundance of bacterioplankton varied from 2604 ± 436 × 10
3
cells/mL in brackish waters to 468 ± 91 × 10
3
cells/mL in seawater. The average values of bacterial production in waters with a salinity of less than 8 and more than 22 PSU were 17.43 and 4.91 mgC m
–3
day
–1
, respectively. In autumn, the bacterial abundance decreased towards the sea from 1289 ± 385 × 10
3
cells/mL in freshwaters to 85 ± 37 × 10
3
cells/mL in the offshore part; the value of production decreased by more than an order of magnitude. With an increase in salinity, the proportion of cells with active electron transport chain in the abundance of bacterioplankton decreased from 5.8 to 0.6%. Thus, the distribution of river runoff, marked by salinity, proved to be the main factor affecting the spatial distribution and activity of bacterioplankton. However, the mechanism of such regulation remains unclear.
It is believed that the waters of rivers flowing into the Kara Sea (predominantly discharge of the Yenisei and Ob rivers) can propagate to the east, penetrating the Laptev Sea with the current along ...the coast. This can occur with the so-called eastern transfer of continental runoff. During a cruise of the R/V
Akademik Mstislav Keldysh
in 2018, traces of riverine waters were discovered in the Vilkitsky Strait. Hydrochemical data suggest with great confidence that these waters were transported from the Ob–Yenisei estuary region. This is because in 2018, pronounced eastern transfer of water from the Kara to the Laptev Sea was observed. A year earlier, continental runoff was not observed in the strait. The fact that transformed riverine waters were transported into the strait from the Kara Sea is also corroborated by the results of surface water sampling along the route of the vessel.
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