scholarly journals Phytoplankton adaptation strategies under the influence of climatic changes and anthropogenic pressure on the Black Sea coastal ecosystems on the example Sevastopol Bay

2020 ◽  
Vol 37 ◽  
pp. 34-42
Author(s):  
Liudmila Stelmakh ◽  
Nela Kovrigina ◽  
Tatiana Gorbunova
Keyword(s):  
Water Temperature ◽  
Black Sea ◽  
Phytoplankton Biomass ◽  
Anthropogenic Pollution ◽  
The Black Sea ◽  
Nitrate Content ◽  
Anthropogenic Pressure ◽  
Total Phytoplankton Biomass ◽  
Sevastopol Bay ◽  
Total Phytoplankton

Some ways of the Black Sea coastal waters phytoplankton community adaptation to changes in water temperature, nutrients concentration and anthropogenic pollution have been identified on the example of the Sevastopol Bay. The increase in water temperature and decrease in nutrient content in the studied waters during 2000 – 2014 caused a gradual decrease in the chlorophyll a concentrations, total phytoplankton biomass and its re-composition, predominantly in the summer and autumn periods. The phytoplankton restructuring was predominantly reflected by a decrease in relative diatoms contribution in the total phytoplankton biomass and an increase in dinoflagellates contribution. Among the dominant diatoms species, the share of resistant species to high temperatures, pollution, low nitrate content in the water and microzooplankton grazing was increasing. An increase in nitrate concentration in the studied waters in 2020 led to increase in total phytoplankton biomass and a predominance of diatoms species, which under the stated conditions did not lead to bloom emergence as were regularly observed earlier in the Sevastopol region.

Effect of phytoplankton adaptation on the distribution of its biomass and chlorophyll a concentration in the surface layer of the Black Sea

2019 ◽  
Vol 48 (4) ◽  
pp. 404-414 ◽  
Author(s):  
Liudmila Stelmakh ◽  
Tatiana Gorbunova
Keyword(s):  
Surface Layer ◽  
Spatial Variability ◽  
Black Sea ◽  
Phytoplankton Biomass ◽  
Abiotic Factors ◽  
Nitrogen Concentration ◽  
The Black Sea ◽  
Total Phytoplankton ◽  
Upper Mixed Layer ◽  
Effect Of Light

Abstract Using the field data collected in the Black Sea in September 2005–May 2013, the authors studied the spatial variability of the ratio of organic carbon to chlorophyll a (C:Chl a) in the sea surface layer (0–1 m). The C:Chl a ratio is an important parameter that reflects the phytoplankton adaptation to abiotic factors. Its maximum variations occurred in September–October 2005 and October 2010 when the highest spatial variability of average light intensity and nitrogen concentration was observed in the upper mixed layer. As a result, the maps of phytoplankton biomass differed from chlorophyll maps. In August 2011, no effect of light or nitrogen on the spatial variability of the C:Chl a ratio was found. Changes in the contribution of dinoflagellates to the total phytoplankton biomass affected the C:Chl a ratio variability, which was two times lower compared to September–October 2005 and October 2010. Also, the spatial distribution of phytoplankton biomass differed from the distribution of chlorophyll a concentration only in some areas of the sea. In May 2013, environmental factors slightly varied across the study area and the spatial variability of the C:Chl a ratio was insignificant. Therefore, the map of phytoplankton biomass indicated similarities with the chlorophyll map.

scholarly journals The finding of a rare in the Black Sea polychaete Ctenodrilus serratus (Schmidt, 1857) (Annelida, Cirratulidae)

2020 ◽  
Vol 5 (2) ◽  
pp. 109-111
Author(s):  
E. V. Lisitskaya ◽  
N. A. Boltachova
Keyword(s):  
Water Temperature ◽  
Black Sea ◽  
Morphological Characteristics ◽  
The Black Sea ◽  
Single Specimen ◽  
Schematic Representation ◽  
Bottom Soil ◽  
Sevastopol Bay ◽  
Oyster Farm

In July 2019, three polychaetae specimens of the genus Ctenodrilus were found in oyster cages on silted oyster shells. The cages from a mussel-and-oyster farm located at the outer roadstead of Sevastopol Bay were suspended at a depth of 6–8 m. The bottom soil under the mussel-and-oyster farm is silted sand, and the depth is of 16 m. During the sampling, water temperature was of +23 °C, and the salinity was of 17.7 ‰. Thus, according to morphological characteristics, polychaetae we found should be classified as Ctenodrilus serratus (Schmidt, 1857). Photographs of alive and fixed polychaetae, chaetae patterns, and a schematic representation of their number by segments are presented. At the beginning of the XX century, a single specimen of this species was found in the Black Sea.

scholarly journals The sea water temperature impact upon Gonothyraea loveni (Allman) hydroid development on the artificial substrates in the Sevastopol Bay (the Black Sea)

2019 ◽  
Author(s):  
Keyword(s):  
Water Temperature ◽  
Black Sea ◽  
Sea Water ◽  
Seawater Temperature ◽  
Artificial Substrates ◽  
Effect Of Temperature ◽  
The Black Sea ◽  
Temperature Range ◽  
Wide Range ◽  
Sevastopol Bay

The effect of seawater temperature on the subsidence and development of the Gonothyraea loveni (Allman) hydroid at a specific point in the water area was discussed This allows us to trace the connection of seasonal changes in sea temperature with the process of sedimentation of planules and the development of hydroid G. loveni on artificial substrates of various exposures in the Sevastopol bay. Observations were carried out over two periods: from 1979 to 1987. and from 2011 to 2015. The temperature range of 5-10 °C corresponds to the subsidence of planul on plates with a community 10 days aged in the autumn and spring periods. The peak of subsidence was detected at a water temperature of 9 °C. At this time, the greatest number of plates with settled hydroids was detected (22%). The number of hydrotecas in the temperature range of 11-19 °C reaches maximum values due to sedimentation and active growth of colonies, since the frequency of occurrence of plates with hydroids during this period is halved and remains at this level at higher temperatures (17-24 °C). With an increase in the exposure of substrates up to 30 days, the bulk of the plates with hydroid (80%) are concentrated in the temperature range of 6–11 °C. When the temperature of water in the sea is 16-24 °C, plates with hydroids are less than 5%, which is determined in addition to the effect of temperature by the massive subsidence of Botryllys schlosseri (Pallas), which replaces the hydroid. In communities of 2-12 months of age, the hydroid G. loveni develops over a wide range of temperatures, from 5 to 23 °C. Dynamic changes in communities show that the growth of colonies occurs at a temperature of 5-9 °C with a maximum intensity of 10 to 15 °C. At temperatures above 17 °C, the reduction of colonies occurs. Key words: subsidence, development of hydroid Gonothyraea loveni, the temperature of the sea water of the Sevastopol Bay, the Black sea

scholarly journals Phytoplankton Growth Rate and Microzooplankton Grazing under Conditions of Climatic Changes and Anthropogenic Pollution in the Coastal Waters of the Black Sea (Sevastopol Region)

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3230
Author(s):  
Lyudmyla Stelmakh ◽  
Nelya Kovrigina
Keyword(s):  
Growth Rate ◽  
Black Sea ◽  
Coastal Waters ◽  
Phytoplankton Biomass ◽  
Trophic Levels ◽  
The Black Sea ◽  
Anthropogenic Pressure ◽  
Diatom Species ◽  
Nutrition Quality ◽  
Microzooplankton Grazing

In the coastal waters of the Black Sea near Sevastopol, a gradual temperature elevation and an increase in anthropogenic pressure since the early 2000s have caused significant structural and functional changes in phytoplankton. Currently, there is a significant decrease in the contribution of small diatom species (Skeletonema sp. and Chaetoceros socialis H.S.Lauder as well as coccolithophorids Emiliania huxleyi (Lohmann) W.W.Hay and H.P.Mohler) to the total phytoplankton biomass in these waters. Previously these species caused regular weak blooms. In the warm periods (from May to October), during which the main phytoplankton biomass is formed, large diatom species Pseudosolenia calcar-avis (Schultze) B.G.Sundström, 1986, Proboscia alata (Brightwell) Sundström and dinoflagellates predominate. Therefore, the maximum values of the phytoplankton community’s specific growth rate are about two times lower than in the preceding periods and do not exceed 1.10–1.40 day−1. There was also a decrease observed in the microzooplankton grazing rate, which, during the year, was no higher than 0.70–1.20 day−1. This is primarily conditioned by the increased role of large algae in phytoplankton, which means a decline in nutrition quality for microzooplankton. As a result of the joint influence of nutrition quality and water pollution, the relative share of net primary production consumed by microzooplankton in the warm periods of the year averaged only 32%, which is two times lower than the average values generally accepted for marine ecosystems. This means that the transfer of matter and energy from phytoplankton to higher trophic levels is significantly decreased.

DISTRIBUTION OF DISSOLVED METHANE IN SURFACE COASTAL WATERS OF THE NORTHEASTERN PART OF THE BLACK SEA

2017 ◽  
Author(s):  
Elena Kovaleva ◽  
Elena Kovaleva ◽  
Alexander Izhitskiy ◽  
Alexander Izhitskiy ◽  
Alexander Egorov ◽  
...  
Keyword(s):  
Black Sea ◽  
Natural Waters ◽  
Sea Water ◽  
The Black Sea ◽  
Methane Formation ◽  
Anthropogenic Pressure ◽  
Russian Science ◽  
Southeastern Part ◽  
Dissolved Methane ◽  
Continental Runoff

Studying of methane formation and distribution in natural waters is important for understanding of biogeochemical processes of carbon cycle, searching for oil and gas sections and evaluation of CH4 emissions for investigations of greenhouse effect. The Black Sea is the largest methane water body on our planet. However, relatively low values of methane concentration (closed to equilibrium with the atmospheric air) are typical of the upper aerobic layer. At the same time, the distribution pattern of CH4 in surface waters of coastal areas is complicated by the influence of coastal biological productivity, continental runoff, bottom sources, hydrodynamic processes and anthropogenic effect. The investigation is focused on the spatial variability of dissolved methane in the surface layer of the sea in coastal regions affected by the continental runoff and anthropogenic pressure. Unique in situ data on methane concentrations were collected along the ship track on 2 sections between Sochi and Gelendzhik (2013, 2014) and 2 sections between Gelendzhik and Feodosia (2015). Overall 170 samples were obtained. Gas-chromatographic analysis of the samples revealed increase of CH4 saturation in the southeastern part of the Crimean shelf and the Kerch Strait area. Such a pattern was apparently caused by the influence of the Azov Sea water spread westward along the Crimean shore from the strait. This work was supported by the Russian Science Foundation, Project 14-50-00095 and the Russian Foundation for Basic Research, Project 16-35-00156 mol_a.

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.

DISTRIBUTION OF DISSOLVED METHANE IN SURFACE COASTAL WATERS OF THE NORTHEASTERN PART OF THE BLACK SEA

2017 ◽  
Author(s):  
Elena Kovaleva ◽  
Elena Kovaleva ◽  
Alexander Izhitskiy ◽  
Alexander Izhitskiy ◽  
Alexander Egorov ◽  
...  
Keyword(s):  
Black Sea ◽  
Natural Waters ◽  
Sea Water ◽  
The Black Sea ◽  
Methane Formation ◽  
Anthropogenic Pressure ◽  
Russian Science ◽  
Southeastern Part ◽  
Dissolved Methane ◽  
Continental Runoff

Studying of methane formation and distribution in natural waters is important for understanding of biogeochemical processes of carbon cycle, searching for oil and gas sections and evaluation of CH4 emissions for investigations of greenhouse effect. The Black Sea is the largest methane water body on our planet. However, relatively low values of methane concentration (closed to equilibrium with the atmospheric air) are typical of the upper aerobic layer. At the same time, the distribution pattern of CH4 in surface waters of coastal areas is complicated by the influence of coastal biological productivity, continental runoff, bottom sources, hydrodynamic processes and anthropogenic effect. The investigation is focused on the spatial variability of dissolved methane in the surface layer of the sea in coastal regions affected by the continental runoff and anthropogenic pressure. Unique in situ data on methane concentrations were collected along the ship track on 2 sections between Sochi and Gelendzhik (2013, 2014) and 2 sections between Gelendzhik and Feodosia (2015). Overall 170 samples were obtained. Gas-chromatographic analysis of the samples revealed increase of CH4 saturation in the southeastern part of the Crimean shelf and the Kerch Strait area. Such a pattern was apparently caused by the influence of the Azov Sea water spread westward along the Crimean shore from the strait. This work was supported by the Russian Science Foundation, Project 14-50-00095 and the Russian Foundation for Basic Research, Project 16-35-00156 mol_a.

Sign in / Sign up

Export Citation Format

Share Document