Thermal fluxes and stability of the upper boundary of deep near-bottom layer in the Black Sea

1997 ◽  
Vol 8 (1) ◽  
pp. 29-38
Author(s):  
V. M. Kushnir
Keyword(s):  
Black Sea ◽  
Bottom Layer ◽  
The Black Sea ◽  
Upper Boundary

scholarly journals On the possible presence of oxygen in the upper sediment layer of the hydrogen sulfide zone in the Black Sea

2019 ◽  
Vol 59 (1) ◽  
pp. 166-169
Author(s):  
P. A. Stunzhas ◽  
M. B. Gulin ◽  
A. G. Zatsepin ◽  
E. A. Ivanova
Keyword(s):  
Black Sea ◽  
Benthic Fauna ◽  
Water Layer ◽  
Bottom Layer ◽  
The Black Sea ◽  
Depth Range ◽  
Sediment Layer ◽  
Bottom Water Layer ◽  
Long Time ◽  
Eukaryotic Organisms

In the northeastern Black Sea the search was performed for living eukaryotic organisms (micro- and meiobenthos) in hypoxic and anoxic conditions as well as measurement of O2 in the bottom water layer and in the upper layer of sediments. The results have shown the presence of a deep maximum abundance of zoobenthos in a depth range of 215–244 m. This aggregation of benthic fauna occupies a layer of 30 m along the vertical. In general, the proportion of active meiobenthos was no greater than 1.5% of the total number of organisms recorded from the sample.The presence of aerobic benthos near the upper boundary of the H2S zone can be explained by: sliding down of sediments from a higher depth; quasi-periodic O2 supply due to fluctuations in the position of the isopycna and/or sinking of waters downslope in the bottom Ekman layer. Also, in the case of physical entry of oxygen into the bottom layer, it can remain for a relatively long time in the upper part of the H2S zone due to the lack of deep Mn+2 flux and reaction with it.

Long-term variations of the location of the upper boundary of the hydrogen-sulphide zone in the Black Sea

2001 ◽  
Vol 11 (3) ◽  
pp. 249-258
Author(s):  
A. M. Suvorov ◽  
A. Kh. Khaliulin ◽  
E. A. Godin
Keyword(s):  
Black Sea ◽  
Hydrogen Sulphide ◽  
The Black Sea ◽  
Long Term Variations ◽  
Upper Boundary

Hydrometeorological Conditions in the Southern Part of the Kerch Strait and the Pre-Strait Zone of the Black Sea as a Potential Area for Industrial Shellfish Cultivation

2020 ◽  
pp. 112-117
Author(s):  
Natalya A. Sytnik
Keyword(s):  
Black Sea ◽  
Bottom Layer ◽  
Water Area ◽  
The Black Sea ◽  
Frequent Change ◽  
Trophic Conditions ◽  
Kerch Strait ◽  
Sea Currents ◽  
Summer Minimum ◽  
Hydrometeorological Conditions

Considered materials on the hydrometeorological conditions of the Kerch Strait and the Black Sea. The data on the wind regime in the study areas are presented. The materials on currents and water exchange in the southern part of the Kerch Strait and the Black Sea waters are presented. The average monthly, annual, minimum and maximum values of air temperature at the coastal hydrometeorological stations are analyzed. In the seasonal course of salinity, in contrast to the regularities in the sea zone (in the surface and bottom layers), there is no summer minimum in the bottom layer of the strait. This indicates the development of coastal upwellings in the Black Sea in the summer, which facilitates the penetration of the Black Sea waters into the strait in the bottom layer. The oxygen saturation of the waters in the strait (both in the surface and in the bottom layers) is higher than in the sea area. This indicates a more intensive course of production processes. The stable Azov currents are most favorable for the plantations located in the strait near the Crimean coast during the collection of larvae on the collector and for the improvement of trophic conditions in the plantation areas. For the purification of coastal waters from suspended matter, the Black Sea currents are preferred. The frequent change of the Azov and Black Sea currents creates favorable conditions for the effective operation of mariculture farms. On the basis of the studies carried out, conclusions were drawn about the possibility of industrial cultivation of mollusks in the water area of the Kerch Strait and the Black Sea.

scholarly journals The energy spectrum of the current velocity in deep layers of the Black Sea

2019 ◽  
Vol 488 (5) ◽  
pp. 550-554
Author(s):  
A. A. Klyuvitkin ◽  
A. G. Ostrovskii ◽  
A. P. Lisitzin ◽  
S. K. Konovalov
Keyword(s):  
Energy Spectrum ◽  
Black Sea ◽  
Blue Shift ◽  
Bottom Layer ◽  
The Black Sea ◽  
Spectral Energy ◽  
Data Set ◽  
Deep Layers ◽  
Deep Current ◽  
First Time

In 2016-2017, for the first time, nearly year-long measurements of the current velocities were carried out below the thermocline at a depth of 100 m and at a depth of 1700 m that was about 100 m above the seabed by using the mooring station in the deep central part of the Black Sea. Analysis of the new data set allowed us to uncover the followings. In the near-bottom layer, the significant flow velocities were recorded, reaching a peak magnitude of 0.13 m/s. Near the frequency of 110-6 Hz, in the transition region of the energy spectrum, the spectral energy of the deep current was close to that observed in the same range in the subthermocline layer of the sea. In the range of balanced geostrophic motions, the energy spectrum had a slope of -2,8 that should be compared to a spectrum slope of -1,8 obtained for current below the thermocline. The regular strong horizontal currents were observed near the local inertial frequency fI. There was a blue shift of the inertial maximum up to 5% with respect to fI in the energy spectrum.

scholarly journals Vertical Distribution of Phosphates in the Black Sea Based on the Expeditionary Data, 2016–2019

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
S. I. Kondratev ◽  
D. S. Khoruzhii ◽  
◽  
Keyword(s):  
Vertical Distribution ◽  
Black Sea ◽  
Organic Phosphorus ◽  
The Black Sea ◽  
Marine Hydrophysical Institute ◽  
Isopycnic Surface ◽  
Concentration Maximum ◽  
Suboxic Zone ◽  
Upper Mixed Layer ◽  
Upper Boundary

Purpose. The purpose of the study is to analyze the features of vertical distribution of phosphates and dissolved organic phosphorus (Porg) in the Black Sea at the present period. Methods and Results. The data obtained by the scientists of Marine Hydrophysical Institute in the Black Sea within the economic zone of Russia in 2016–2019 were used. At more than 200 deep-sea stations, a cassette of 12 bathometers (the Seabird-Electronics STD-instrument) was applied for taking hydrochemical samples at certain isopycnic surfaces, usually at σt = 16.30; 16.25; 16.20; 16.20; 16.15; 16.10; 16.05; 16.00; 15.95; 15.90; 15.80; 15.50, 14.0 kg/m3. At the coastal shallow-water stations, samples were taken at the 10 m intervals. Such a scheme permitted to carry out vertical sampling in the upper mixed layer and in the suboxic zone (including its upper boundary) with possible minimum of phosphates, to determine the depth of hydrogen sulfide formation and the location of the phosphates concentration maximum in the upper part of the anaerobic zone. Conclusions. From the surface to isopycn σt = 14.4 kg/m3, the content of phosphates and Porg does not exceed 0.1 µM; below this isopycnic surface, the phosphates concentration begins to increase, whereas of Porg remains at the same level. At all the profiles of the phosphates vertical distribution, the phosphates concentration minimum was recorded near the isopycnic surface σt = 15.8 kg/m3, and its maximum – near the isopycnic surface σt = 16.2 kg/m3. The minimum content of phosphates varied within 0–1.5 µM; in 2016–2017 the phosphates concentration maximum did not exceed 8 µM; in 2018, in many cases, it was higher than 12 µM, and once, near the Kerch Strait, it exceeded 17 µM. Increase in the magnitude of the maximum phosphates concentration (in the previous studies in 1988–2013, it did not exceed 8 µM) is assumed to be related to installation of the supports for constructing the Kerch Bridge.

Relationship between the upper boundary of the H2S zone and the respective isopycnic surface in the Black Sea with the index of atmospheric circulations

1997 ◽  
Vol 8 (4) ◽  
pp. 293-296 ◽  
Author(s):  
V. N. Eremeev ◽  
A. M. Suvorov ◽  
A. Kh. Khaliulin ◽  
E. A. Godin ◽  
A. A. Sizov
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Isopycnic Surface ◽  
Atmospheric Circulations ◽  
Upper Boundary

scholarly journals Annual cycle of sound-scattering mesoplankton in the oxycline and hypoxic zone in the northeastern Black Sea

2020 ◽  
Author(s):  
Alexander G. Ostrovskii ◽  
Vladimir A. Solovyev ◽  
Dmitry A. Shvoev
Keyword(s):  
Black Sea ◽  
Annual Cycle ◽  
Bottom Layer ◽  
Acoustic Backscatter ◽  
The Black Sea ◽  
Sound Scattering ◽  
Near Surface ◽  
Hypoxic Zone ◽  
Acoustic Beams ◽  
Temperature Depth

Abstract. To investigate the annual cycle of sound-scattering layers in the Black Sea, a moored profiler equipped with an acoustic Doppler current meter, a conductivity-temperature-depth probe, and fast sensors for dissolved oxygen [O2] was employed. Approximately 13,350 multiparameter profiles from the near-surface layer down to the near-bottom layer were obtained at intervals of 1–2 h from 2013–2020. The acoustic system allowed for observations of ultrasound backscattering at 3 angles at 2 MHz frequency. Combinations of the volume strength data of the 3 acoustic beams (directional acoustic backscatter ratios, R) were found to be a useful tool for visualizing acoustic backscatter patterns associated with mesoplankton in the oxycline and hypoxic zone. The time series of R as a function of [O2] at depths where [O2]

scholarly journals Seasonal variation of the cold intermediate water in the Southwestern Black Sea and its interaction with the Sea of Marmara during the period of 1996-1998

2000 ◽  
Vol 1 (2) ◽  
pp. 31 ◽  
Author(s):  
H. ALTIOK ◽  
H. YUCE ◽  
B. ALPAR
Keyword(s):  
Black Sea ◽  
Coastal Upwelling ◽  
Surface Current ◽  
The Black Sea ◽  
Intermediate Water ◽  
Sea Of Marmara ◽  
Average Temperature ◽  
Layer Flow ◽  
June July ◽  
Upper Boundary

Seasonal variations of the cold intermediate water (CIW) in the southwestern Black Sea and its entrance into the Strait of Istanbul (Bosphorus) within the upper layer flow have been studied by using monthly oceanographic data sets collected in 1996-1998 period. In addition, the advection of the CIW via Strait Of Istanbul to the Sea of Marmara has been investigated.The CIW is a permanent and characteristic water mass of the Black Sea, markedly observed in the northwestern Black Sea. It is transported with the Rim Current along the boundary of the basin. The average temperature of the CIW is about 6o C. The 8oC isotherms defines its upper and lower boundaries. The upper boundary of CIW rises up to the 20 m depth in the shelf and coastal upwelling regions with a thickness of 40 m. On the other hand, the depth of the upper boundary may decrease down to 40 m with a thickness of 120 m in the anticyclonic regions.The CIW, located between 30 and 65m depths, was observed from April to September at the northern approaches of the Strait of Istanbul in the Black Sea. However, the CIW, within the Black Sea's upper layer flow, does not enter into the strait in the beginning (April, May) and at the end (September) of this period. The CIW between 20 and 50m water depths was observed in the northern entrance of the strait in summer (June, July and August) and it was carried into the strait by the southbound surface current. Its temperature increases southwards along the strait, due to the mixing with the warmer surface and bottom layers. This increment ranges between 2 and 4oC depending on the rate of mixing. The physically altered waters enter the Sea of Marmara with temperature of 11-14oC.In the Sea of Marmara, a residual cold intermediate layer (CIL) is observed in summer, it is just placed on top of the halocline. The average temperature of the upper layer increases from spring to autumn. In some months, however, there is a decrement in the average temperature of the upper layer. The altered CIW waters entering the Sea of Marmara may be responsible for this cooling.

scholarly journals The short timescale variability of the oxygen inventory in the NE Black Sea slope water

Ocean Science ◽  
2018 ◽  
Vol 14 (6) ◽  
pp. 1567-1579
Author(s):  
Alexander G. Ostrovskii ◽  
Andrey G. Zatsepin ◽  
Vladimir A. Solovyev ◽  
Dmitry M. Soloviev
Keyword(s):  
Black Sea ◽  
Bottom Layer ◽  
Temporal Variations ◽  
The Black Sea ◽  
Low Oxygen ◽  
Oxygen Penetration ◽  
Direct Observations ◽  
Faunal Abundance ◽  
Vertical Displacements ◽  
Oxygenated Water

Abstract. Warm winters have recently become common over the Black Sea, leading to the risk of shoaling oxygen penetration. The insufficient supply of oxygen to the near-bottom layer may result in a decrease in faunal abundance. However, there is a lack of data on the temporal variations in oxygen throughout the water column over short timescales of hours to weeks. In this paper, new observations over the upper part of the NE Black Sea continental slope are presented. Regular, frequent measurements were performed using a moored profiler from January to early March 2016. The profiling allowed for direct observations of the temperature in the cold intermediate layer (CIL), pycnocline structure, current velocity, and oxygen stratification and in particular, the depths of hypoxia onset. The average local oxygen inventory below a depth of 30 m was 24.9 mol m−2. Relatively high/low oxygen inventory cases were related to the thin/thick main pycnocline, which was associated with the onshore/offshore location of the Black Sea Rim Current. The pycnocline hindered the vertical transport of oxygenated water to the CIL. The vertical displacements of the hypoxia onset depth ranged from 97 to 170 m, while the shelf edge depth in this region usually ranged from 90 to 100 m. Intermittently, the hypoxia boundary depth fluctuated on two timescales: ∼17 h due to inertial oscillations and 3–7 days due to current meanders and eddies.

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