scholarly journals Features of seasonal variability of hydrological and hydrochemical characteristics of subsurface waters of the northwestern Black Sea

2021 ◽  
pp. 07-15
Author(s):  
A.A. Valle ◽  
◽  
A.B. Polonsky ◽  
Keyword(s):  
Water Temperature ◽  
Black Sea ◽  
River Runoff ◽  
Data Availability ◽  
The Black Sea ◽  
Hydrochemical Characteristics ◽  
Subsurface Waters ◽  
Subsurface Layers ◽  
Upper Mixed Layer ◽  
The Stability

In our work, based on the archival data of observations carried out in 1955 – 2015, hydrological and hydrochemical characteristics in the 10–30 m layer in the northwestern shelf (NWS) of the Black Sea, including the Danube estuary area are analyzed. Intra-annual changes in dissolved oxygen and water temperature in the NWS and in the Danube estuary area are shown to have a well-pronounced seasonal character. Water temperature in the estuary area of the Danube is characterized by lower values in all seasons than in the NWS. Salinity at the horizons of 10 and 20 m in winter in the estuary area of the Danube is lower than in the NWS due to the freshening of the upper mixed layer by river runoff. In spring, resulting from increased river runoff, an increase in the stability of water stratification occurs, which prevents the spread of heat inland and vertical exchange of oxygen. The strongest freshening in the studied layer is established at the horizon of 10 m. In spring, the southerly winds “trap” river waters in the shallower part of the shelf, and westerly winds give rise to the spread of freshened waters to the east. The summer-autumn period is characterized by low intensity of vertical and horizontal water exchange, which reduces the flow of oxygen to the subsurface layers. Harmonic analysis shows that in the Danube estuary area and in the NWS, the annual signal is dominant for temperature, salinity and oxygen, except for salinity at the 30 m horizon in the estuary area of the Danube. The semiannual harmonic of salinity at 30 m in the estuarine area of the Danube is most likely related to both limited data availability and their noisiness.

Hydrochemical Characteristics of Water of Balaklava Bay and Adjacent Coastal Part of the Black Sea

2000 ◽  
Vol 36 (6) ◽  
pp. 15
Author(s):  
Ye. A. Kuftarkova ◽  
N. P. Kovrigina ◽  
N. Yu. Rodionova
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Hydrochemical Characteristics

Seasonal variations of the dinoflagellate algae Noctiluca scintillans abundance in the western Arabian Sea and the northern Black Sea

2021 ◽  
Author(s):  
Sergey Piontkovski ◽  
Khalid Al Hashmi ◽  
Yuliya Zagorodnaya ◽  
Irina Serikova ◽  
Vladislav Evstigneev ◽  
...  
Keyword(s):  
Black Sea ◽  
Mixed Layer ◽  
Algal Blooms ◽  
Arabian Sea ◽  
Temporal Dynamics ◽  
The Black Sea ◽  
Northeast Monsoon ◽  
Major Peak ◽  
Noctiluca Scintillans ◽  
Upper Mixed Layer

<p>Seasonal variability is a powerful component of the spatio-temporal dynamics of plankton communities, especially in the regions with oxygen-depleted waters. The Arabian Sea and the Black Sea are typical representatives of these regions. In both, the dinoflagellate Noctiluca scintillans (Macartney) Kofoid & Swezy, 1921, is one of the abundant plankton species which forms algal blooms. Sampling on coastal stations in the upper mixed layer by the plankton nets with the 120-140 µm mesh size was carried out in 2004-2010. Monthly data were averaged over years. A comparison of seasonal patterns of Noctiluca abundance pointed to the persistence of a bimodal seasonal cycle in both regions. The major peak was observed during spring in the Black Sea and during the winter (Northeast) monsoon in the Arabian Sea. The timing of the second (minor) peak was different over regions as well. This peak was modulated by advection of seasonally fluctuating velocity of coastal currents which transport waters enriched by nutrients by coastal upwelling. The abundance of Noctiluca of the major peak (with the concentration around 1.5*10<sup>6</sup> cells m<sup>-3</sup>) was from one to two orders as much high in the western Arabian Sea compared to the northern Black Sea. The remotely sensed chlorophyll-a concentration during the time of the major seasonal peak exhibited a fivefold difference over these regions. In terms of nutrient<sub></sub>concentration in the upper mixed layer (in particular, nitrates and silicates), a difference of about one order of magnitude was observed.</p>

scholarly journals BALLAST WATER POLLUTION RISK ASSESSMENT IN THE BLACK SEA

2021 ◽  
Vol 10 (4) ◽  
pp. 35-40
Author(s):  
Vasile RAŢᾸ ◽  
Liliana RUSU
Keyword(s):  
Risk Assessment ◽  
Black Sea ◽  
Marine Environment ◽  
Ballast Water ◽  
Safety Net ◽  
The Black Sea ◽  
Natural Food ◽  
Economic Activities ◽  
Living Organisms ◽  
The Stability

Since the emergence of humanity, the marine environment has provided a safety net in many ways, has fostered socio-economic development, creating links between states, between continents. In the same time, it represents a priority source of food for a considerable percentage of the population. The same marine environment also creates solutions to current global problems, as a potential source of sustainable energy for the future. In recent decades, the stability of this ecosystem has been  considerably shaken by the various types of pollution resulting from human activities. The Black Sea is not immune to these results from economic activities, such as the transport of goods by water, which creates the context for the migration of living organisms from one geographical region to another. The threat of ecosystems has been intensified by the process of globalization, by changing the natural food chains following the accidental introduction of non- indigenous marine life by discharging ballast water from ship tanks. Risk assessment to limit the effects of this biohazard problem is the first step in a normal regional chain of action..

Hydrophysical and Hydrochemical Characteristics of the Sea Areas Adjacent to the Estuaries of Small Rivers of the Russian Coast of the Black Sea

2014 ◽  
Vol 54 (3) ◽  
pp. 293-308
Author(s):  
P. O. Zavialov ◽  
P. N. Makkaveev ◽  
B. V. Konovalov ◽  
A. A. Osadchiev ◽  
P. V. Khlebopashev ◽  
...  
Keyword(s):  
Black Sea ◽  
Small Rivers ◽  
The Black Sea ◽  
Hydrochemical Characteristics

Results of Monitoring of Temperature Conditions of Migration and Fishing of the Azov Khamsa

2020 ◽  
pp. 71-77
Author(s):  
Boris N. Panov ◽  
Elena O. Spiridonova ◽  
Michail M. Pyatinskiy ◽  
Aleksandr S. Arutyunyan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Water Temperature ◽  
Black Sea ◽  
Sea Surface ◽  
The Black Sea ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Kerch Strait ◽  
Flood Zone

The paper presents the results of monitoring the process of migration and fishing of the Azov khamsa in April-May and October-November, 2019. The research used daily maps of sea surface temperature (SST) of the Black and Azov seas, built in the hydrometeorological Center of Russia according to NCDC/NOAA (Operational module Yessim - hmc.meteorf.ru/sea/black/sst/sst_black.htm) and daily fishing information of the Center for Monitoring of Fisheries and Communications. It is shown that in the spring, khamsa clusters begin to disperse and move to feeding places after the water temperature reaches 11 °C, and at a water temperature of 14-15 °C, the fish becomes much more mobile and the clusters finally disperse. In autumn, the Azov khamsa began to concentrate in the pre-flood zone of the Sea of Azov at an average SST of 16-17 °C, with a SST of 14-16 °C, the khamsa went out into the Kerch Strait. The active output of the khamsa into the Black Sea began at the SST of the pre-flood zone of 15 °C and almost stopped at the SST of about 13 °C. The average SST in the Kerch Strait dropped to 11 °C these days.

scholarly journals Interannual Variability of the Wind-Wave Regime Parameters in the Black Sea

2020 ◽  
Vol 27 (5) ◽  
Author(s):  
P. N. Lishaev ◽  
V. V. Knysh ◽  
G. K. Korotaev ◽  
◽  
◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Black Sea ◽  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Temperature Fields ◽  
The Black Sea ◽  
Layer Depth ◽  
Upper Mixed Layer

Purpose. The investigation is aimed at increasing accuracy of the temperature field reconstruction in the Black Sea upper layer. For this purpose, satellite observations of the sea surface temperature and the three-dimensional fields of temperature (in the 50–500 m layer) and salinity (in the 2.5–500 m layer) pseudo-measurements, previously calculated by the altimetry and the Argo floats data, were jointly assimilated in the Marine Hydrophysical Institute model. Methods and Results. Assimilation of the sea surface temperature satellite observations is the most effective instrument in case the discrepancies between the sea surface and the model temperatures are extrapolated over the upper mixed layer depth up to its lower boundary. Having been analyzed, the temperature profiles resulted from the forecast calculation for 2012 and from the Argo float measurements made it possible to obtain a simple criterion (bound to the model grid) for determining the upper mixed layer depth, namely the horizon on which the temperature gradient was less or equal to ≤ 0.017 °C/m. Within the upper mixed layer depth, the nudging procedure of satellite temperature measurements with the selected relaxation factor and the measurement errors taken into account was used in the heat transfer equation. The temperature and salinity pseudo-measurements were assimilated in the model by the previously proposed adaptive statistics method. To test the results of the sea surface temperature assimilation, the Black Sea hydrophysical fields were reanalyzed for 2012. The winter-spring period (January – April, December) is characterized by the high upper mixed layer depths, well reproducible by the Pacanowski – Philander parameterization, and also by the low values (as compared to the measured ones) of the basin-averaged monthly mean square deviations of the simulated temperature fields. The increased mean square deviations in July – September are explained by absence of the upper mixed layer in the temperature profiles measured by the Argo floats that is not reproduced by the Pacanowski – Philander parameterization. Conclusions. The algorithm for assimilating the sea surface temperature together with the profiles of the temperature and salinity pseudo-measurements reconstructed from the altimetry data was realized. Application of the upper mixed layer depths estimated by the temperature vertical profiles made it possible to correct effectively the model temperature by the satellite-derived sea surface temperature, especially for a winter-spring period. It permitted to reconstruct the temperature fields in the sea upper layer for 2012 with acceptable accuracy.

scholarly journals Different aspects of studying a diatom Cylindrotheca closterium (Ehrenberg) Reimann et Lewin 1964 in natural and laboratory conditions

2019 ◽  
Vol 4 (2) ◽  
pp. 52-62 ◽  
Author(s):  
L. I. Ryabushko ◽  
D. S. Balycheva ◽  
A. V. Bondarenko ◽  
S. N. Zheleznova ◽  
A. A. Begun ◽  
...  
Keyword(s):  
Light Intensity ◽  
Water Temperature ◽  
Sea Of Japan ◽  
Black Sea ◽  
The Black Sea ◽  
The Sea Of Japan ◽  
Average Cell ◽  
Cylindrotheca Closterium ◽  
Laboratory Conditions ◽  
Maximum Abundance

The article summarizes original and literary data on different aspects of studying Cylindrotheca closterium (Ehrenberg) Reimann et Lewin 1964 in two biotopes – phytoplankton and microphytobenthos – of the Black Sea, the Sea of Azov, and the Sea of Japan for the period from 1976 to 2016. The aim of the work is to present the results of the study mainly of own data on the morphology, systematics and ecology of C. closterium in different seas and under cultivation in the laboratory. Information on the history of the species origin and its nomenclature changes is given. C. closterium belongs to the phylum Bacillariophyta, class Bacillariophyceae, order Bacillariales Hendey 1937, family Bacillariaceae Ehrenb. 1831, genus Cylindrotheca Rabenhorst 1859 emend. Reim. et Lewin 1964. This benthoplanktonic species occurs in the plankton, in littoral and sublittoral zones of the seas. The species is marine and brackish-water; it is a cosmopolite common in different geographical zones of the World Ocean. The results of studying alga by various methods under natural and experimental conditions in light and transmission electron microscopes of C. Zeiss LIBRA-120 are presented. The quantitative data of C. closterium were determined by direct counting of the cells in the Goryaev’ camera (V = 0.9 mm³) in light microscopes BIOLAM L-212, C. Zeiss Axioskop 40 with the program AxioVision Rel. 4.6 at 10×40, 10×100, and Olympus BX41 (Tokyo, Japan) with lenses UPLanF140× and 100×1/30 oil immersion. Cultivation of C. closterium was carried out in the cumulative mode on the nutrient medium F, volume of 1 L under light intensity of 13.7 klx and temperature of +20…+21 °C. Morphology data of this species from different seas were obtained. The average cell sizes of C. closterium are: 25–260 µm length, 1.5–8 µm width; 12–25 fibulae in 10 µm. The results of cultivation in the laboratory conditions showed that the average cell sizes reached 148.17 µm (length) and 8 µm (width) at the temperature of +19…+20 °C and light intensity of 13 klx; length of cells reached 162.12 µm in the exponential phase of growth and 172.07 µm – in the stationary phase. C. closterium has an important practical significance as a source of fucoxanthin, since this alga is intensively cultivated for production of biologically active substances. Our experimental data showed that during laboratory cultivation the fucoxanthin concentration in a diatom biomass can reach 11 mg·g-1 of dry mass. The new data obtained are relevant and important; they can be used in different fields of science and medicine. The seasonal dynamics of population abundance of C. closterium in different ecotopes (epizoon of invertebrates and their food spectra, epiphyton of bottom vegetation, periphyton of the experimental and anthropogenic substrates of the different seas) is presented for the first time. The maximum abundance of the species population (65.6·10³ cells·cm-2) was registered in the epizoon of the mussel Mytilus galloprovincialis Lam. in March at the water temperature of +7.7 °C at a depth of 2.5 m in the Black Sea. The maximum abundance was registered in the epiphyton of green algae (896·10³ cells·cm-2) and in the periphyton of asbestos plates (728·10³ cells·cm-2) in August at the water temperature of +24.5 °C in the Sea of Japan. The abundance dynamics of C. closterium natural populations in the local habitats changed depending on the season, the depth, and the type of substrate. The similarities and differences in the distribution of C. closterium in the sea microphytobenthos are discussed.

scholarly journals Seasonal and Long-Term Variability of Coccolithophores in the Black Sea According to Remote Sensing Data and the Results of Field Investigations

2022 ◽  
Vol 10 (1) ◽  
pp. 97
Author(s):  
Sergey V. Vostokov ◽  
Anastasia S. Vostokova ◽  
Svetlana V. Vazyulya
Keyword(s):  
Black Sea ◽  
Large Scale ◽  
Remote Sensing Data ◽  
Cold Season ◽  
The Black Sea ◽  
Local Character ◽  
Field Investigations ◽  
Mass Development ◽  
Upper Mixed Layer

Based on satellite data from the SeaWiFS, MODIS-Aqua, and MODIS-Terra scanners, the long-term dynamics of coccolithophores in the Black Sea and their large-scale heterogeneity have been studied. During the twenty years in May and June, mass development of coccolithophores population of different intensities was recorded annually. Summer blooms of coccolithophores reached peak levels in 2006, 2012, and 2017, after abnormally cold winters. It was noted that in conditions of low summer temperatures, the blooming of coccolithophores could be significantly reduced or acquire a local character (2004). In the anomalous cold summer of 2001, coccolithophore blooms were replaced by the mass growth of diatoms. Over twenty years, numerous signs of coccolithophores mass development in the cold season have been revealed. Winter blooms develop mainly in warm winters with periods of low wind activity. The formation of a thermocline and the surface layer’s stability are essential factors for initiating winter blooms of coccolithophores. It was noted that after the winter blooms of coccolithophores, their summer growth was poorly expressed. It is shown that during periods of rapid growth, the bulk of coccolithophores is concentrated in the upper mixed layer and thermocline. During the blooming period, the share of coccolithophores in phytoplankton biomass constituted 70–85%. The intensity of coccolithophore’s blooms is associated with the previous diatoms’ growth level. The effect of eddies circulation on the distribution and growth of coccolithophores is considered.

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