Dmitry Frey

• PhD
• Institute of Oceanology. PP Shirshov Russian Academy of Sciences

The Antarctic Bottom Water flow in the Vema Channel of the Southwest Atlantic is one of the strongest abyssal flows in the World Ocean. The spatial structure of abyssal waters in the channel has been previously studied by different authors only at two locations: at the Vema Sill in the southern part of the channel and at the Vema Extension in its n...

Plain Language Summary The polar regions are responsible for the formation of deep and bottom waters in the ocean, which account for a significant portion of its volume. The motion of these cold and dense waters is vital for oceanic heat transfer and has a direct impact on the Earth's climate. These deep flows also control sedimentation processes a...

The Vema Channel is a deep narrow passage in the South Atlantic and a main path for bottom water which flows northward from the Argentine Basin to the Brazil Basin and after all into the North Atlantic. The thermohaline structure and dynamics in it have been studied for many years. In this study we report our new data on dissolved oxygen and nutrie...

Measurements of oceanographic characteristics, currents, and tides in the Fram Strait and the Greenland Sea are analyzed using historical measurement data. Measurements on moorings across the Fram Strait made it possible to estimate the speeds of the East Greenland and West Spitsbergen currents. It is shown that the speeds of these currents are low...

We analyzed Conductivity-temperature-depth (CTD) and moored Acoustic Doppler Current Profiler (ADCP) measurements in the western Barents Sea carried out onboard the Russian R/V Akademik Mstislav Keldysh (cruise 68) in July–August 2017. A hydrographic section in the Bear Island Trough has been made. Comparison of water properties in the trough and i...

Measurements of temperature, salinity, and currents in the Amazon River plume over a section in the open ocean of the western tropical North Atlantic (38°48′ W) are considered. The measurements were carried out using an AML Base X CTD probe in the upper layer and a flow-through system that measures salinity, turbidity, and chlorophyll-a content in...

In this research communication, we report the results of a field survey conducted in a part of the plume of the Amazon River between 0° and 5°N and offshore of the 28 m isobaths in November of 2022, during the low river discharge season. By comparing the observed vertical salinity profiles ‘disturbed’ by continental discharges within the plume with...

Measurements of temperature and salinity in the Amazon River plume in the open ocean of the western tropical North Atlantic are considered. The measurements were carried out using the AML CTD probe in the upper layer and a flow-through system that measures salinity and turbidity of seawater while the vessel is on the way. Additionally, archive ocea...

We present multi-sensor measurements from satellites, unmanned aerial vehicle, marine radar, thermal profilers, and repeated conductivity–temperature–depth casts made in the Kara Gates strait connecting the Barents and the Kara Seas during spring tide in August 2021. Analysis of the field data during an 18-h period from four stations provides evide...

Abyssal channels are the key points controlling bottom circulation of the World Ocean. They provide meridional transport of the coldest Antarctic Bottom Water between deep-water basins influencing the meridional overturning circulation and the climate on a global scale. Here we show that the synoptic variability of deep-water flows including blocki...

The goal of this work is to study the dynamical structure of eddies of the Brazil‐Malvinas Confluence zone (BMC eddies) using direct velocity measurements carried out by Shipborne Acoustic Doppler Current Profiler during five oceanographic cruises performed in 2016–2022. In total, in situ data of 13 BMC eddies, including nine anticyclones and four...

We present multi-sensor measurements from satellites, unmanned aerial vehicle, marine radar, thermal profilers and repeated conductivity-temperature-depth casts made in the Kara Gates strait connecting the Barents and the Kara Seas during spring tide in August 2021. Analysis of the field data during an 18-hour period from four stations evidence tha...

The present study is the attempt to combine oceanologic measurements and biochemical analysis, which is as possible to implement on board as in a laboratory with chosen certain statistics to reveal trophic conditions and the environment state in which Antarctic krill live in season in real time on site. The fatty acid constituents of total lipids i...

The Kara Sea receives ~ 1/3 of total freshwater discharge to the Arctic Ocean, mainly from the large Ob and Yenisei rivers. The Ob-Yenisei plume covers wide area in the central part of the Kara Sea during ice-free season (June–October) and accumulates ~ 1000 km³ of freshwater volume. In late autumn, the Kara Sea becomes covered by ice, which hinder...

We present the results of measurements of thermohaline and dynamical structures, as well as hydrochemical parameters of near-bottom water in the Western Gap (Azores-Gibraltar Fracture Zone, Northeast Atlantic). The data were collected during cruise 59 of the research vessel Akademik Ioffe in October 2021. The results of the analysis showed that wat...

Results of a joint Russian-Brazilian expedition to study the dynamics of continental river runoff in the ocean associated with the Amazon plume are presented. The stations of the study region covered the seaward part of the Amazon plume. The work was carried out in the dry season (November). The data of in situ measurements and satellite data show...

A combination of a high sediment input and intense bottom currents often leads to the formation of contourites (sediments deposited or significantly reworked by bottom currents). Both of these components are present in the Vema Fracture Zone valley which is the most important passageway for the distribution of the Antarctic Bottom Water from the We...

This is a review paper about measurements of internal tides in the Kara Gates Strait. Kara Gates is one of the straits where intense internal tides are generated by tidal currents overflowing the transversal sill of the strait. Tidal currents are superimposed on a constant current from the Barents to the Kara Sea. Field studies of internal waves in...

A section of 46 CTD/Lowered Acoustic Doppler Current Profiler stations along the Vema Fracture Zone (VFZ) was made for the first time with a repeat of the transverse section on the main sill (at 41° W) for the sixth time. Potential temperature of Antarctic Bottom Water when it flows into the fracture increases from 1.3°С to 1.6°C. This temperature...

We analyze internal waves based on measurements on cruise 87 of the R/V Akademik Mstislav Keldysh in the Bransfield Strait near Half Moon Island and calculations using a numerical model. The measurements were carried out on January 25, 2022 for four hours using a line of temperature and pressure sensors, along with the measurements with a CTD probe...

Oceanographic data from measurements in deep-water channels of the Atlantic Ocean were analyzed. Data from two different methods were compared: CTD/LADCP measurements from research vessels and data from autonomous mooring stations. The comparison showed that discrepancies between the data obtained by two different methods can significantly exceed t...

In January–February 2022, a CTD/LADCP section across the Powell Basin in the Weddell Sea with hydrochemical observations was carried out in the Antarctic expedition of the R/V “Akademik Mstislav Keldysh”. Transect was located from the Antarctic Peninsula to the South Orkney Islands; thus, it crossed the Weddell Gyre in its northwestern part. As a r...

The spatial distribution of the main primary productivity parameters in the Bransfield Strait in the Antarctic summer presents. The integrated primary production in the strait varied from 435 to 741 mgC/m2 per day. The share of primary production in the total production of phyto- and bacterioplankton in the upper 10th layer was 82–91%. Potential ph...

The Antarctic Circumpolar Current plays the key role in the circulation of the Southern Ocean and affects the distribution of heat by the ocean on the global scale. The study of the dynamics and structure of this current becomes especially important in a changing climate. The current is well revealed by satellite altimetry data, which makes possibl...

The sea straits of the Antarctic Peninsula region are characterized by intense currents, the presence of sea ice and large icebergs, strong tides, and many other factors that form the thermohaline structure of the waters in this region and its temporal variability. The existence of local ecological communities depends on the thermohaline properties...

Field measurements of the Malvinas Current (MC) velocity distribution were performed at the western slope of the Argentine Basin in the South Atlantic Ocean between 47° and 43°S including several sections across the current. The data were collected in January and March 2020 using a Shipborne Acoustic Current Doppler Profiler (SADCP) and allowed us...

Three-dimensional structure of currents in the Bransfield Strait (BS) was measured in 2017 over 50 transects across the strait using a Shipborne Acoustic Current Doppler Profiler (SADCP) onboard the R/V Akademik Sergey Vavilov and Akademik Ioffe. These data were used to determine local features of the three-dimensional velocity field of the current...

The major Siberian rivers form large river plumes in the Arctic Ocean, which govern structure of the sea surface layer at the Arctic shelf. These river plumes were explicitly studied during the warm period in summer and early autumn characterized by high river runoff and ice-free conditions. However, little is known about processes, which occur wit...

Information is presented on the work performed to study the flow of Antarctic Bottom Water along the entire length of the Vema Fracture Zone in the tropical part of the North Atlantic Ridge and Russian-Brazilian field studies in the largest river plume of the World Ocean, on the shelf of the northern part of Brazil near the mouth of the Amazon Rive...

Strong acceleration of abyssal flows in narrow deep‐water channels and fracture zones is a key feature of bottom circulation in the Atlantic Ocean. In the Equatorial Atlantic, these bottom currents transport Antarctic Bottom Water (AABW) over the Mid‐Atlantic Ridge from west to east. The main pathway for Antarctic waters in this region is the Roman...

Purpose. The purpose of the work is to study the different-scale features of distribution of the hydroop tical and hydrological characteristics in the Antarctic Sound Strait based on the contact and satellite measurements carried out in January, 2022 in the 87th cruise of the R/V “Akademik Mstislav Keldysh”. Methods and Results. The data of complex...

The aim of this study is to trace how the fine-thermohaline and kinematic structure, formed over a section along 45.8° S in the interaction zone of the outer Patagonian Shelf (PS) and Malvinas (Falkland) Current (MC) System waters, affect the spatial distribution of bio-optical characteristics, phyto/zooplankton, birds, and marine mammals. For the...

An expedition to study the ecosystems of the Atlantic sector of the Antarctic was carried out in cruise 87 of R/V Akademik Mstislav Keldysh between January 19 and February 14, 2022. The studies were carried out in the key regions for understanding modern processes in the ecosystem of the Southern Ocean and in the regions of interest for Russian fis...

Properties of the abyssal current of Antarctic Bottom Water (AABW) from the Vema Channel are studied based on temperature, salinity, and velocity profiler (CTD/LADCP) data. Previous studies over a period of almost 30 years revealed that very intense current of AABW exists in the Vema Channel. Later, it was found that this current consists of two br...

The Bransfield Strait is a relatively deep and narrow channel between the South Shetland Islands and the Antarctic Peninsula contributing to the water transport between the Pacific and Atlantic sectors of the Southern Ocean. The strait can be divided into three deep separate basins, namely, the western, central, and eastern basins. The sources of d...

Supercritical hydraulically controlled overflow of Antarctic Bottom Water from the Weddell Sea has been observed in the Orkney Passage during field measurements in February 2022. The Orkney Passage is the main pathway for the densest layer of Antarctic Bottom Water flow from the Weddell Sea to the Scotia Sea. The bottom current overflows the sill a...

Seawater properties in two intense rings in the South Atlantic are considered. One ring separated from the Brazil Current and the other from the Malvinas Current. The analysis is based on the CTD casts and SADCP measurements from the onboard velocity profiler. The optical properties, chemical parameters, methane concentration, and biological proper...

The inflow of warm and saline Atlantic water from the North Atlantic to the Western Arctic is provided by two branches, namely, the Fram Strait branch water and the Barents Sea branch water. The pathways of these branches merge at the St. Anna Trough, and then both branches propagate eastward along the continental slope, albeit at different depths....

We observed two different icebergs near the Antarctic Peninsula. One was one of the largest ever observed (160 km long). It calved from the Filchner Glacier. Fresher water field surrounded the iceberg and drifted together with the iceberg. The other glacier (800 m long) was aground in the Bransfield Strait. A strong current was flowing around this...

Contourites are sediments deposited or substantially reworked by the persistent action of bottom currents which are capable of forming a wide range of erosional and depositional features on the seafloor. The study of contourites is a multidisciplinary topic linking physical oceanography and marine geology. While near-bottom circulation is an import...

This work is focused on the structure and inter-annual variability of the freshened surface layer (FSL) in the Laptev and East-Siberian seas during ice-free periods. This layer is formed mainly by deltaic rivers among which the Lena River contributes about two thirds of the inflowing freshwater volume. Based on in situ measurements, we show that th...

Satellite altimetry is an efficient instrument for detection dynamical processes in the World Ocean, including reconstruction of geostrophic currents and tracking of mesoscale eddies. Satellite altimetry has the potential to detect large river plumes, which have reduced salinity and, therefore, elevated surface level as compared to surrounding sali...

Тёплая атлантическая водная масса, фактически являющаяся продолжением Гольфстрима, поступает из Северной Атлантики в Северный Ледовитый океан двумя путями: одна струя течёт через пролив Фрама к северу от архипелага Шпицберген и Земли Франца-Иосифа, вторая – через Баренцево море к югу от этих архипелагов. В районе жёлоба Святой Анны, расположенного...

Изучение теплых атлантических вод в Арктике в последнее время привлекает все больше внимания, т.к. считается, что они играют значительную роль в изменении климата в Арктике и влияют на сокращение площади сезонного льда. Также атлантические воды являются потенциальным источником биогенов для шельфовой зоны арктических морей России, поэтому исследова...

The focus area of this monograph is the central part of a tectonic ridge within the Florianopolis (Rio Grande) Fracture ZoneFracture zones in the southern Brazil BasinBrazil Basin. The ridge is swept by the bottom current of the Lower Circumpolar Deep WaterLower Circumpolar Deep Water (LCDW) propagating from the Argentine BasinArgentine Basin to th...

Plain Language Summary Water is an efficient temperature regulator. Large energy exchange is required to produce small changes in water temperature. Since 71% of the Earth's surface is covered by oceanic water, the ocean plays a fundamentally important role in the climate system. The ocean transports, stores, and exchanges with the atmosphere subst...

We investigate tidal and higher frequency internal waves southeast of Hopen Island of the Svalbard archipelago using shipborne CTD and ADCP data, model simulations, and satellite observations. The experiment was carried out in the marginal ice zone region. Previous numerical simulations predicted high amplitudes of internal tides here. A series of...

We present a CTD dataset of repeated sections across the Vema Channel in the South Atlantic approximately along 31°12’ S between longitudes 39°18.0 W and 39°30.0’ W. The Vema Channel is a narrow conduit for Antarctic Bottom Water across the Rio Grande Rise. The measurements at CTD stations (Conductivity-Temperature-Depth) across the Vema Channel we...

Direct velocity measurements of the Malvinas Current (MC) were carried out on multiple occupations of five transects across the flow using a Shipborne Acoustic Current Profiler (SADCP) on the R/V Akademik Sergey Vavilov and Akademik Mstislav Keldysh. These data are used to determine local features of the three‐dimensional velocity field of the curr...

In March 2019, Lake Vallunden was surveyed to construct a chart of ice thickness. Lake Valunden is a lake in Spitsbergen at the top of the Van Mijen Fjord. The lake is approximately 1 km long, 600 m wide, and 10 m deep. It is connected to the Van Mijen Fjord by a channel 100 long and 10 m wide. The tides in the fjord are high; hence periodical tida...

This work is focused on the seasonal and interannual variability of the freshened surface layer (FSL) in the Kara Sea during ice‐free periods. The majority of annual freshwater runoff inflows to the Kara Sea during the freshet period in June–July. As a result, a large low‐salinity and strongly stratified FSL is formed in the central Kara Sea at the...

The structure of northerly overflow of Antarctic Bottom Water (AABW) in the East Atlantic through passages in the East Azores Ridge (37° N) from the Madeira Basin to the Iberian Basin is studied on the basis of hydrographic measurements in October 2011 and in September 2013, historical data from the WOD18 database, and recent data on bottom topogra...

We study the flows in the Charlie Gibbs Fracture Zone and Bight Fracture Zone in the Mid-Atlantic Ridge, the overflows in the Strait of Gibraltar, in the Strait of Denmark, Faroe Bank Channel, and in the Bear Island Trough. The flows are investigated on the basis of CTD/LADCP casts and moorings and review of previous publications. The Charlie Gibbs...

We analyze the inflow of bottom waters to the Northeast Atlantic through the Vema, Romanche, and Chain fracture zones and their further propagation in the basin. In 1983, Mantyla and Reid wrote that bottom waters propagating through the Romanche Fracture Zone influence only the equatorial and southeastern part of the Atlantic Ocean and do not sprea...

We analyze the flow of Antarctic Bottom Water in the Brazil Basin and the flow of bottom water from the Guiana Basin through the westward equatorial channels into the North American Basin. Much consideration is related to the eastward flow in the equatorial fracture zones in the Mid-Atlantic Ridge: the Romanche and Chain fracture zones. A special r...

Flows of Antarctic Bottom Water in the Vema Fracture Zone and other fractures in the northern part of the Mid-Atlantic Ridge are analyzed. We study the flows of Antarctic Bottom Water through the fracture zones in the northern part of the Mid-Atlantic Ridge based on the CTD and LADCP observations in 2006, 2014, 2015, and 2016. We measured the therm...

This chapter describes a general scheme of the distribution of Antarctic waters in the abyssal of the Atlantic Ocean after propagating from their sources in the Southern Ocean. The chapter also summarizes the quantitative indicators of bottom flows in the abyssal channels. Comparison of the limits of distribution of Antarctic waters is given depend...

This chapter summarizes our knowledge about the structure and propagation of waters in the deep and bottom layers of the Atlantic Ocean, description of the properties of the deep, and bottom waters and conditions of their formation. Despite the fact that almost the whole book is related to the spreading of Antarctic Bottom Water, the dynamics of th...

In this chapter we consider formation of bottom water in the Weddell Sea and further spreading of bottom water to the north and around the Antarctic continent. The distribution paths of Antarctic waters between the basins of the Atlantic are confined to the depressions of the bottom topography. From the Weddell Sea, Antarctic waters in the abyss sp...

Two regions exist in the Bransfield Strait: the region of the Bransfield Strait along the South Shetland Islands with Transitional Zonal Water with Bellingshausen Sea influence and the region along the northeastern coast of the Antarctic Peninsula with colder and more saline Transitional Zonal Water with Weddell Sea influence. The narrow jet stream...

The bottom waters of Antarctic origin flow to the Brazil Basin along three pathways: through the Vema Channel, through the Hunter Channel, and over the Santos Plateau. The depths of the Vema Channel exceed 4600 m, while the background depths of the Santos Plateau and Hunter Channel are approximately 4000 m. The Vema Channel is a narrow passage betw...

A strong front between cold and warm surface waters was found in the northwestern part of the Weddell Sea (Powell Basin) in February 2020. The front was manifested by sharp horizontal gradients of temperature, chemical, and optical properties. Differences in the concentrations and species of phytoplankton and zooplankton on both sides of the front...

This book is dedicated to the analysis of bottom waters flows through underwater channels of the Atlantic Ocean. The study is based on recent observations of the authors, analysis of historical data, numerical modeling, and literature review. For example, studying both the measurements from the World Ocean Circulation experiment in the 1990s and re...

We analyze measurements of bottom currents and thermohaline properties of water north of the Vema Channel with the goal to find pathway continuations of Antarctic Bottom Water flow from the Vema Channel into the Brazil Basin. The analysis is based on CTD/LADCP casts north of the Vema Channel. The flow in the deep Vema Channel consists of two branch...

During cruise 79 of R/V Akademik Mstislav Keldysh in the Atlantic Antarctic, information is supplied using optical and radar high-, mid-, and low-resolution satellite data, in combination with geoinformation technologies. During field studies from December 2019 to February 2020, preliminarily processed information obtained by a multisatellite Earth...

We analyze measurements of bottom currents and thermohaline properties of water north of the Vema Channel with the goal to find pathway continuations of the Antarctic Bottom Water flow from the Vema Channel into the Brazil Basin. The analysis is based on the CTD/LADCP casts north of the Vema Channel. The flow in the deep-water Vema Channel consists...

We analyze measurements of bottom currents and thermohaline properties of water north of the Vema Channel with the goal to find pathway continuations of Antarctic Bottom Water flow from the Vema Channel into the Brazil Basin. The analysis is based on CTD/LADCP casts north of the Vema Channel. The flow in the deep Vema Channel consists of two branch...

We analyze measurements of bottom currents and thermohaline properties of water north of the Vema Channel with the goal to find pathway continuations of Antarctic Bottom Water flow from the Vema Channel into the Brazil Basin. The analysis is based on CTD/LADCP casts north of the Vema Channel. The flow in the deep Vema Channel consists of two branch...

High-resolution seismoacoustic and multibeam data revealed a large field of sediment waves covering the Santa Catarina Plateau on the Brazilian Southern Margin. Within the field several zones were determined: a zone of large sediment waves (up to 70 m in height), a zone of smaller sediment waves (15–30 m in height) and a zone of buried sediment wav...

In 2013 and 2018, Shirshov Institute of Oceanology performed 12 stations with conductivity‐temperature‐depth and lowered acoustic Doppler current profiler (LADCP) profiling in the southwestern part of the Brazil Basin in order to find continuations of hydraulic controlled flow of the coldest Antarctic bottom water that propagates along the deepest...

The goal of this research is to modify and apply a version of high‐resolution three‐dimensional numerical model for simulations of bottom circulation and to study the flows of Antarctic Bottom Water in abyssal channels of the Atlantic Ocean using this model. We adjusted the Institute of Numerical Mathematics Ocean Model σ‐level ocean circulation mo...

Six day temperature records carried out at the three mooring levels revealed isotherm fluctuations in the Denmark Strait sill in July 2018 caused by internal waves. In addition to the field measurements, fluctuations of isopycnals were estimated on the basis of a numerical model. It was shown that the vertical displacements of water particles cause...

In April 2017 and in October 2018, a Russian expedition on the R/V “Akademik Sergey Vavilov” in the South-West Atlantic carried out measurements of temperature, salinity, and velocity over a standard section across the deep Vema Channel at 31(градус) 12(минут) S. Extremely high and extremely low velocities and transports of Atlantic Bottom Water (A...

In April 2017 and October 2018, a Russian expedition on the R/V Akademik Sergei Vavilov in the Southwest Atlantic carried out measurements of the temperature, salinity, and velocity over a standard section across the deep Vema Channel at 31°12′ S. Extremely high and extremely low velocities and transports of Antarctic Bottom Water for the entire hi...

Six-day temperature records carried out at the three mooring levels revealed isotherm fluctuations in the Denmark Strait sill in July 2018 caused by internal waves. In addition to the field measurements, fluctuations of isopycnals were estimated on the basis of a numerical model. It was shown that the wave height (vertical displacements of water pa...