scholarly journals Trends of long-term changes in chlorophyll concentration, primary production of phytoplankton and water temperature in the shelf regions of the Black Sea

2021 ◽  
Vol 18 (4) ◽  
pp. 228-235
Author(s):  
V Kovalyova ◽  
◽  
Z.Z. Finenko ◽  
V.V. Suslin ◽  
◽  
...  
Keyword(s):  
Primary Production ◽  
Water Temperature ◽  
Black Sea ◽  
Chlorophyll Concentration ◽  
The Black Sea ◽  
Long Term Changes

scholarly journals Tendencies of long-term changes of temperature fields, salinity and water level of the North-Western part of the Black Sea

2019 ◽  
pp. 84-94
Author(s):  
N. Berlinsky ◽  
R. Gavriluk ◽  
O. Danilenko
Keyword(s):  
Water Temperature ◽  
Sea Level ◽  
Black Sea ◽  
Temperature Increase ◽  
The Black Sea ◽  
Sea Level Fluctuations ◽  
The North ◽  
Long Term Changes ◽  
North Western

The paper analyzes the variability of hydrological characteristics of the North-Western part of the Black for different temporal scales: long-term, seasonal and synoptic. The traditional methods of geographic investigations, such as comparative-geographic, retrospective and cartographic methods, were used. When analyzing sea level data packages and thermohaline characteristics mathematical methods, including statistical, correlation and regression analysis, were used. As a result of the conducted research quantitative estimates of tendencies of long-term changes of the thermohaline characteristics and level in the North-Western part of the Black Sea were received. Over the period of 1982-2005 an increase of water temperature in the North-Western part of the Black Sea was observed: in winter water temperature in the surface layer increased by 2оC, in the bottom layer – by more than 2оC. Over the period of 1990-2005 an increase of an average annual water temperature in Odesa area constituted 1,2°C. The most considerable and statistically significant temperature increase took place during the summer hydrological season: an average summer temperature increased during this period by 2,7оC. During transitional seasons (autumn and spring) there was also a tendency of temperature increase, however, statistically significant trend was observed only during the autumn period. There is a statistically significant negative trend observed for long-term changes of salinity. For the period of 1990-2005 an average annual salinity decreased by 1.36 ‰. A tendency of salinity decrease was observed for all seasons of the year, however, statistically significant trends are observed only in winter and summer. A close relationship between long-term changes in water salinity and runoff of the Dnieper River was also established. A sea level rise is observed at all stations of the North-Western part of the Black Sea. Over the period of 1947-2012 an average annual sea level in Odesa increased by 14 cm. An analysis of climatic changes of wind-induced sea level fluctuations showed that the frequency of surges of varying intensity remained almost unchanged, however, the frequency of sweeps changed significantly. Over the period of 1980-2012, as opposed to the period of 1947-1979, the frequency of minor sweeps (no more than 30 cm) increased, and the frequency of significant (more than 30 cm) and very significant (more than 50 cm) sweeps, on the contrary, decreased by about 5%-6%. Changes of wind-induced sea level fluctuations' character harmonize with wind direction and wind speed over the North-Western part of the Black Sea.

Long -Term Changes in the Fish Fauna of the Karkinitsky Gulf of the Black Sea

2020 ◽  
Vol 46 (6) ◽  
pp. 452-460
Author(s):  
R. E. Belogurova ◽  
E. P. Karpova ◽  
E. R. Ablyazov
Keyword(s):  
Black Sea ◽  
Fish Fauna ◽  
The Black Sea ◽  
Long Term Changes

Long-term Changes in Sevastopol Bay (the Black Sea) with Particular Reference to the Ichthyoplankton and Zooplankton

2001 ◽  
Vol 52 (1) ◽  
pp. 1-13 ◽  
Author(s):  
A.D. Gordina ◽  
E.V. Pavlova ◽  
E.I. Ovsyany ◽  
J.G. Wilson ◽  
R.B. Kemp ◽  
...  
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Sevastopol Bay ◽  
Long Term Changes

Long-term changes in nutrient supply of phytoplankton growth in the Black Sea

2013 ◽  
Vol 117-118 ◽  
pp. 53-64 ◽  
Author(s):  
Alexander S. Mikaelyan ◽  
Andrey G. Zatsepin ◽  
Valeriy K. Chasovnikov
Keyword(s):  
Black Sea ◽  
Nutrient Supply ◽  
Phytoplankton Growth ◽  
The Black Sea ◽  
Long Term Changes

scholarly journals Long-term dynamic of reproductive performance of European anchovy Engraulis encrasicolus Linnaeus, 1758 and its connection with temperature

2017 ◽  
Vol 2 (2) ◽  
pp. 3-19
Author(s):  
G. V. Zuev ◽  
T. N. Klimova
Keyword(s):  
Water Temperature ◽  
Black Sea ◽  
Relative Abundance ◽  
The Black Sea ◽  
Western Coast ◽  
European Anchovy ◽  
Engraulis Encrasicolus ◽  
European Anchovy Engraulis Encrasicolus ◽  
Calendar Dates

European anchovy (Engraulis encrasicolus Linnaeus, 1758) is one of the most numerous species of fish in the Azov-Black Sea basin. It is the main commercial fishery object, its share being about 80 %. Assessment of the functional state of the anchovy population and its dynamics in conditions of the climatic warming was one of the topical tasks in contemporary research. The paper is devoted to the study of a long-term dynamic of anchovy population: reproductive parameters and its relation with water temperature for the purpose of potential prediction. The results of our own investigations made in 2000–2015 in the area bordering the south-western coast of Crimean peninsula (Sevastopol–Balaklava region) have been considered in the paper. The eggs were collected with Bogorov – Rass net (BR-80/113) from the layer of 0–10 m. Adult specimen were caught with pound seines. 702 ichthyoplankton samples and 941 mature anchovy females (gonad maturation stage V, VI–IV and VI–V) were analyzed. Calendar dates and duration of spawning season, intensity and efficiency of spawning, intraspecific composition of mature anchovy females were researched. Calendar dates of anchovy spawning beginning near the south-western coast of Crimea in 2000–2014 varied from the 2ⁿᵈ decade of May (early spawning) to the 3ʳᵈ decade of June (late spawning); finishing dates – from the 3ʳᵈ decade of August to the 3ʳᵈ decade of September. Total reproductive period duration was 8–14 weeks, average – 11 weeks. In long-term plan the time shift for earlier calendar dates was determined at the start of the spawning. Maximum peak of spawning intensity in 2012–2013 varied from 33.6 to 78.7 % (average 51.2 %). Peak of population spawning was in July – August, its repeatability in July – 25 and in August 66.7 %. The peak spawning shift to the earlier time was determined in perennial plan: in 2000–2005 years peak spawning periodicity amounts in August to 100 %; in 2007–2013 – only 50 %. Absolute number of eggs (spawning efficiency) change from 1.6 to 29.9 specimen·m-2 in 2000–2014 years (average 10.3 specimen·m-2). Low, average and high yielding years with number of eggs less than 10, 10–20 and more than 20.0 specimen·m-2 were determined. The average spawning efficiency was: 5.1, 14.5 and 25.0 specimen·m-2 respectively. Spawning efficiency in high-yielding years exceeded 1.7 and 4.9 times the efficiency of low and average-yielding years. In long-term plan the positive efficiency spawning trend was determined. In 2000–2001 the intraspecific structure reconstruction of anchovy took place, followed by redistribution of numerical relation in composition of spawning part of the Azov and the Black Sea subspecies in favor of the last one. In 2000–2004 relative abundance of Black Sea anchovy amounted 33.3 %, in 2005–2011 years – 76.7 %. Simultaneously a considerable catch growth was registered. Сorrelation coefficient of the Black Sea anchovy’s relative abundance and catch was 0.92. Calendar time of spawning beginning, its intensity and efficiency are closely connected with the water temperature. Lower temperature limit for mass spawning was 17.5 °С. The region of “maximum favorable spawning temperature” lays in the range of 23 °C and warmer. Nearly 2/3 of population reproductive potential is realized within this temperature range.

scholarly journals LONG-TERM CHANGES IN THE PRESIPITATION AT THE BLACK SEA COAST OF THE CAUCASUS

2020 ◽  
Vol 1 (5) ◽  
pp. 161-167
Author(s):  
A.V. Parfenova ◽  
◽  
L.V. Dashkevich ◽  
Keyword(s):  
Black Sea ◽  
Coefficient Of Variation ◽  
Meteorological Station ◽  
The Black Sea ◽  
The Caucasus ◽  
Modern Period ◽  
Black Sea Coast ◽  
Long Term Changes ◽  
Sea Coast

Long-term changes in the amount of precipitation on the Black Sea coast of the Caucasus according to data of the hydro-meteorological stations Anapa, Tuapse and Sochi are considered. The observation data analysis of for the selected periods revealed an increase in the average yearly precipitation from the beginning of the twentieth to the beginning of the twenty-first centuries for all hydro-meteorological stations with a slight decrease in the coefficient of variation. Seasonal changes in precipitation regime are pronounced in the region. The highest increase in seasonal precipitation was noted at the Anapa hydro-meteorological station for winter, then for spring and autumn. At the Tuapse and Sochi hydro-meteorological stations also tended to increase precipitation in spring and autumn, but was noted a slight decrease in winter in the modern period. At the same time, for all seasons such growth is provided mainly by an increase in the minimum seasonal values (for all stations), as well as maximum ones in spring (for all stations) and autumn (hydro-meteorological station Anapa). In modern period relative to the twentieth century it is possible to note a slight decrease in the coefficient of variation in winter and spring (for all hydro-meteorological stations), and an increase in summer (for hydro-meteorological stations Anapa and Tuapse). The redistribution of precipitation by seasons was revealed from the beginning of the twentieth to the beginning of the twentyfirst centuries. The most significant changes affected the hydro-meteorological station Tuapse: the share of autumn and spring precipitation increased from 25 to 31 % and from 18 to 22 %, respectively, while the share of summer precipitation decreased from 26 to 18 %. The share of winter precipitation increased from the first to the third selected periods (from 30 to 35 %), after which it decreased to 29 % in the modern period.

scholarly journals Modeling long-term changes of the Black Sea ecosystem characteristics

2012 ◽  
Vol 9 (3) ◽  
pp. 2039-2080 ◽  
Author(s):  
V. L. Dorofeyev ◽  
T. Oguz ◽  
L. I. Sukhikh ◽  
V. V. Knysh ◽  
A. I. Kubryakov ◽  
...  
Keyword(s):  
Black Sea ◽  
Inorganic Nitrogen ◽  
The Black Sea ◽  
Mnemiopsis Leidyi ◽  
Biogeochemical Model ◽  
Food Web Structure ◽  
Decadal Scale ◽  
Basin Scale ◽  
Long Term Changes

Abstract. A three dimensional coupled physical-biological model is provided for the Black Sea to investigate its long-term changes under the synergistic impacts of eutrophication, climatic changes and population outbreak of the gelatinous invader Mnemiopsis leidyi. The model circulation field is simulated using the high frequency ERA40 atmospheric forcing as well as assimilation of the available hydrographic and altimeter sea level anomaly data for the 30 yr period of 1971–2001. The circulation dynamics are shown to resolve well the different temporal and spatial scales from mesoscale to sub-basin scale and from seasonal peaks to decadal scale trend-like changes. The biogeochemical model includes the main vertical biological and chemical interactions and processes up to the anoxic interface zone. Its food web structure is represented by two phytoplankton and zooplankton size groups, bacterioplankton, gelatinous carnivores Mnemiopsis and Aurelia, opportunistic species Noctiluca scientillans. The nitrogen cycling is accommodated by the particulate and dissolved organic nitrogen compartments and the dissolved inorganic nitrogen in the forms of ammonium, nitrite and nitrate. The ecosystem model is able to simulate successfully main observed features and trends of the intense eutrophication phase (from the early 1970s to the early 1990s), but points to its modification to simulate better the ecosystem conditions of the post-eutrophication phase.

Sign in / Sign up

Export Citation Format

Share Document