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.

scholarly journals EXPERIENCE IN DETAILED LANDSCAPE MAPPING OF THE BLACK SEA ABRASION COAST AT THE NORTH-WESTERN CAUCASUS

2021 ◽  
Vol 7 (17) (2) ◽  
pp. 108-116
Author(s):  
A.M. Aleynikova ◽  
A.P. Andreeva ◽  
O.N. Lipka ◽  
M.V. Krylenko
Keyword(s):  
Black Sea ◽  
Large Scale ◽  
Remote Sensing Data ◽  
Field Research ◽  
The Black Sea ◽  
Western Caucasus ◽  
Coastal Mapping ◽  
The North ◽  
Landscape Unit ◽  
North Western

The landscape units of the Black Sea coast of the North-Western Caucasus have complex and dynamic structures. Mapping of such systems is possible only on a large scale, by superimposing remote sensing data on field research materials. The detailed landscape maps of the marine abrasive coasts of this region were produced for the first time. The landscape structure includes identified hierarchic units: stows, substows, narrow stretched belts, and land facies. A substow was selected as the main unit of analysis for the coastal mapping. The landscape unit map exposes the activity of slope processes and the potential danger areas in the coastal zone.

scholarly journals Influence of Long-Term Changes in the Large-Scale Sea Level Pressure Field on the Wind Regime and the Wind Stress Curl in the Black Sea

2021 ◽  
Vol 28 (2) ◽  
Author(s):  
I. G. Shokurova ◽  
A. A. Kubryakov ◽  
M. V. Shokurov ◽  
◽  
◽  
...  
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
Wind Stress ◽  
Large Scale ◽  
Pressure Field ◽  
The Black Sea ◽  
Wind Stress Curl ◽  
Sea Level Pressure ◽  
Level Pressure

Purpose. The paper is aimed at studying the relationship between the wind regime and the wind stress curl in the Black Sea and the long-term changes in the large-scale sea level pressure field in winter months. Methods and Results. The data on wind speed and sea level pressure in January – February from the NCEP/NСAR reanalysis for 1948–2018 are used. Based on the 6-hour data, the synoptic conditions accompanied by high and low values of the wind stress curl in the sea were determined. The synoptic situations in which a vast anticyclone is located north and northeast of the sea, and the area of low pressure – to the southwest of the sea in the Mediterranean region, are accompanied by the northeast and east winds, and by the cyclonic curl predominance. On the contrary, passing of the cyclones to the north of the sea and increase of pressure to the southwest are followed by the westerly and southwesterly winds, and by the anticyclonic curl predominance. Extremely high monthly mean values of the cyclonic curl were observed in those years, when the area occupied by the Siberian anticyclone increased and expanded westward, so that the Black Sea was on the southwestern periphery of its spur. Extremely low values of the anticyclonic curl were noted when the Azores anticyclone area expanded to the Mediterranean region. The wind stress curl changes on the multidecadal scales have shown its relation to the global changes in the field of the sea level pressure and the sign of the pressure anomalies at the low latitudes. Conclusions. The opposite sign of the surface pressure anomalies to the northeast and southwest of the sea is accompanied by the highest values of the wind stress curl.

Oithona davisae: naturalization in the Black sea, inter-annual and seasonal dynamics, effect on the structure of the planktonic copepod community

2019 ◽  
Vol 59 (6) ◽  
pp. 1008-1015
Author(s):  
A. D. Gubanova ◽  
O. A. Garbazey ◽  
D. A. Altukhov ◽  
V. S. Mukhanov ◽  
E. V. Popova
Keyword(s):  
Black Sea ◽  
Coastal Waters ◽  
Native Species ◽  
Significant Decline ◽  
Acartia Tonsa ◽  
The Black Sea ◽  
Copepod Community ◽  
Oithona Davisae ◽  
Sevastopol Bay

Long-term (20032014) routine observations of zooplankton in Sevastopol Bay (the Black Sea) have allowed the naturalization of the invasive copepod Oithona davisae to be studied in the Black Sea coastal waters. Inter-annual and seasonal variability of the species and their impact on the native copepod community have been analyzed. The invasion of O. davisae and their undoubted dominance in terms of abundance were shown to alter the community structure but, at the same time, the abundances of the native species did not decrease, excepting the Black Sea earlier invader Acartia tonsa. A significant decline in A. tonsa numbers over the stages of O. davisae establishment and naturalization provided evidence of competition between the species. O. davisae have been demonstrated to gain competitive advantage over A. tonsa, that ensured their fast dispersal in the Black Sea, acclimatization in the new habitat and the successful competition over native species.

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 Long term trends in the sea surface temperature of the Black Sea

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 491-501 ◽  
Author(s):  
G. I. Shapiro ◽  
D. L. Aleynik ◽  
L. D. Mee
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Black Sea ◽  
Sea Surface ◽  
The Black Sea ◽  
The North ◽  
Sst Variability ◽  
Long Term Trends ◽  
Cooling Trend

Abstract. There is growing understanding that recent deterioration of the Black Sea ecosystem was partly due to changes in the marine physical environment. This study uses high resolution 0.25° climatology to analyze sea surface temperature variability over the 20th century in two contrasting regions of the sea. Results show that the deep Black Sea was cooling during the first three quarters of the century and was warming in the last 15–20 years; on aggregate there was a statistically significant cooling trend. The SST variability over the Western shelf was more volatile and it does not show statistically significant trends. The cooling of the deep Black Sea is at variance with the general trend in the North Atlantic and may be related to the decrease of westerly winds over the Black Sea, and a greater influence of the Siberian anticyclone. The timing of the changeover from cooling to warming coincides with the regime shift in the Black Sea ecosystem.

Air recirculation and ventilation in the coastal regions of the Black Sea

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Galina Surkova
Keyword(s):  
Black Sea ◽  
Eastern Coast ◽  
The Black Sea ◽  
Additional Risk Factor ◽  
Additional Risk ◽  
Sea Breezes ◽  
North Eastern ◽  
Favorable Conditions ◽  
Parameter Values

AbstractAn initial investigation of recirculation is carried out for the coast of the Black Sea. The local mesoscale circulations (land-sea breezes, mountain and valley winds) in coastal areas are shown to be an additional risk factor in creating favorable conditions for air stagnation and accumulation of air pollutants in the surface atmosphere layer. Two types of annual recirculation patterns are revealed for northern and north-eastern coast of the Black Sea. Long-term changes in recirculation are investigated. It is shown that the recirculation parameter values remained quasistable until the mid-1970s. Since 1976–1977, steady intensification of recirculation in both winter and summer is identified.

Long-term ecological changes in Romanian coastal Waters of the Black Sea

1996 ◽  
Vol 32 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Adriana Cociasu ◽  
Liliana Dorogan ◽  
Christoph Humborg ◽  
Luci Popa
Keyword(s):  
Black Sea ◽  
Coastal Waters ◽  
The Black Sea ◽  
Ecological Changes
Sign in / Sign up

Export Citation Format

Share Document