scholarly journals CHANGES IN THE DOMINANT SPECIES AND SIZE STRUCTURE OF DIATOMS FROM THE SURFACE BOTTOM SEDIMENTS OF THE SEA OF AZOV OVER THE PAST 20 YEARS

2021 ◽  
Vol 1 (6) ◽  
pp. 96-103
Author(s):  
G.V. Kovaleva ◽  
◽  
I.Yu. Gavrilova
Keyword(s):  
Bottom Sediments ◽  
Size Structure ◽  
Sharp Decrease ◽  
Marine Species ◽  
Sea Of Azov ◽  
Diatom Analysis ◽  
The Sea Of Azov ◽  
The Past ◽  
The Stability ◽  
Radical Transformation

The paper presents the results of diatom analysis of surface bottom sediments selected with a range of 20 years. Samples of surface sediments of the Sea of Azov collected in 1998 (before the salinization period) and in 2019 were studied. The results of the diatom analysis of the bottom sediments showed that the sediments were dominated by spores of diatoms from the genus Chaetoceros and stomatocysts of golden algae. In addition to spores and stomatocysts, diatoms from the genus Thalassiosira sp., Coscinodiscus sp., Ditylum brightwellii, Pseudosolenia calcar-avis and Thalassionema nitzschioides were often found in the surface soils of 1998. In the sediments selected in 2019, medium – and large-sized taxa (Actinoptychus senarius, Actinocyclus octonarius, Thalassiosira sp., Coscinodiscus sp.) began to predominate in frequency of occurrence and abundance. The appearance of these species can be associated with an increase in the average salinity of the waters of the Sea of Azov, since most of the representatives of the above taxa belong to marine and brackish-water-marine species. A decrease in freshwater runoff and an increase in salinity in the Sea of Azov can lead not only to a radical transformation of the native microalgae community, but also increases the risk of alien marine species of plankton and benthos. Large-sized diatoms are less attractive as a food base for zooplankton, which can also lead to changes in the native biota of the Sea of Azov. In general, these dangerous transformations can lead to a sharp decrease in the stability of the ecosystem of the Sea of Azov and irreversible consequences.

THE IMPACT OF WIND CONDITIONS ON THE LEVELS OF TOTAL IRON CONTENT IN THE SEA OF AZOV

2017 ◽  
Author(s):  
Yuri Fedorov ◽  
Yuri Fedorov ◽  
Irina Dotsenko ◽  
Irina Dotsenko ◽  
Leonid Dmitrik ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Iron Content ◽  
Iron Concentration ◽  
Total Iron ◽  
Sea Of Azov ◽  
Open Area ◽  
The Sea Of Azov ◽  
Dissolved Iron ◽  
The Impact ◽  
Taganrog Bay

The distribution and behavior of certain of trace elements in sea water is greatly affected by both physical, chemical and hydrometeorological conditions that are showed in the scientific works of prof. Yu.A. Fedorov with coauthors (1999-2015). Due to the shallow waters last factor is one of the dominant, during the different wind situation changes significantly the dynamics of water masses and interaction in the system “water – suspended matter – bottom sediments”.Therefore, the study of the behavior of the total iron in the water of the sea at different wind situation is relevant. The content of dissolved iron forms migration in The Sea of Azov water (open area) varies from 0.017 to 0.21 mg /dm3 (mean 0.053 mg /dm3) and in Taganrog Bay from 0.035 to 0.58 mg /dm3 (mean 0.11 mg /dm3) and it is not depending on weather conditions.The reduction in the overall iron concentration in the direction of the Taganrog Bay → The Sea of Azov (open area) is observed on average more than twice. The dissolved iron content exceeding TLV levels and their frequency of occurrence in the estuary, respectively, were higher compared with The Sea of Azov (open area).There is an increase in the overall iron concentration in the water of the Azov Sea on average 1.5 times during the storm conditions, due to the destruction of the structure of the upper layer and resuspension of bottom sediments, intensifying the transition of iron compounds in the solution.

Organic Matter of Bottom Sediments of the Crimean and Caucasian Coasts (Azov and Black Seas)

2021 ◽  
Author(s):  
E. A. Tikhonova ◽  
Keyword(s):  
Organic Matter ◽  
Black Sea ◽  
Bottom Sediments ◽  
Petroleum Hydrocarbons ◽  
Water Area ◽  
The Black Sea ◽  
Pollution Level ◽  
Sea Of Azov ◽  
The Caucasus ◽  
The Sea Of Azov

As part of the 113th cruise of the R/V “Professor Vodyanitsky”, research was conducted on organic pollution of bottom sediments in the coastal areas of Crimea and the Caucasus, as well as the water area in front of the Kerch Strait. Concentration of chloroformextractable substances was determined by the weight method and that of petroleum hydrocarbons was determined using infrared spectrometry. Both in 2020 and 2016 (the 83d cruise of the R/V “Professor Vodyanitsky”), properties of the bottom sediments of the Crimean and Caucasian coasts were typical of the marine soils of this region. This indicates that the studied water areas are generally in good condition. In accordance with the regional classification of bottom sediment pollution, the maximum concentrations of chloroform-extractable substances obtained for both the Black Sea and the Sea of Azov coast indicate pollution level III (23% of analysed samples). These values were found in bottom sediments in the Sevastopol water area (225 mg·100 g-1), in the coastal area of Cape Tarkhankut (120 mg·100 g-1) and Karadag (120 mg·100 g-1), the southern part of the Sea of Azov (125 mg·100 g-1) and Tuapse (110 mg·100 g-1). The content of chloroform-extractable substances in bottom sediments off the Black Sea coast of the Caucasus and the Sea of Azov coast is slightly lower than that off the Crimean coast. Pollution level II is assigned to bottom sediments in 46 % of the samples, with an average concentration of 72 mg·100 g-1 of air-dry solids. The rest (31 %) of the studied area was classified as conditionally clean (pollution level I, i. e. less than 50 mg·100 g-1). There has been a slight increase in the concentration of petroleum hydrocarbons in the bottom sediments of both the Black Sea and the Sea of Azov and their share in the total amount of chloroformextractable substances. In general, the level of pollution of bottom sediments by organic matter remained unchanged if compared with previous years, in particular with the data from 2016

CHRONOLOGY OF CONTEMPORARY SEDIMENTATION AND POLLUTANTS ACCUMULATION IN THE BOTTOM SEDIMENTS OF THE SEA OF AZOV

2017 ◽  
Author(s):  
Andrey Kuznetsov ◽  
Andrey Kuznetsov ◽  
Yury Fedorov ◽  
Yury Fedorov ◽  
Paul Fattal ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Anthropogenic Impact ◽  
Specific Activity ◽  
Sediment Cores ◽  
Anthropogenic Pressure ◽  
Layer By Layer ◽  
Sediment Layer ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Don River

Bottom sediments formed in the water bodies under the technogenic impact are important environmental factors affecting water quality and hydrobiota. Usually they consist of natural and technogenic material and differ from natural formations by their morphology, chemical and lithological composition, physicochemical and biochemical properties. In the present paper we use the term “sediment layer of anthropogenic impact” to define the sediment layer containing technogenic material and/or chemical pollutants. The determination of its location in the sediment cores, its thickness and accumulation chronology is an important scientific problem. In the paper the results of layer by layer study of Cs-137, Am-241, Pb-210 specific activities as well as concentrations of petroleum components, lead and mercury in 48 sediment cores of the Sea of Azov and the Don River are examined. The sediment core layers are dated by radiological methods. In all the sediment cores the peak of Cs-137 specific activity related to the Chernobyl accident was detected. In the Sea of Azov, this peak is located in the upper sediment layer up to 10 cm thick, however, in the delta and in the near-delta part of the Don River, where the sedimentation rates are more important, it is found at 20 to 40 cm depth. Also in certain sediment cores the second peak of Cs-137 related to the global nuclear fallout of the 1960s was found. The most of petroleum components, lead and mercury quantities are concentrated in the upper sediment layer formed in the last 50 to 70 years, i.e. in the period of the most important anthropogenic pressure. So, this complex approach based on the data on the vertical distribution of technogenic radionuclides and common pollutants in the sediment cores made it possible to identify and delineate the sediment layer of high anthropogenic impact as well as to assess the duration of this impact.

scholarly journals Distribution of Cystoseira s. l. species in the Sea of Azov

Algologia ◽  
2020 ◽  
Vol 30 (4) ◽  
pp. 359-381
Author(s):  
S.Yu. Sadogurskiy ◽  
◽  
S.S. Sadogurska ◽  
T.V. Belich ◽  
S.O. Sadogurskaya ◽  
...  
Keyword(s):  
Open Water ◽  
First Record ◽  
Distribution Range ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
The Past ◽  
Kerch Strait ◽  
Hard Substrates

The information on distribution of the Cystoseira s. l. species in the Sea of Azov (SA) is presented based on the results of our own research and literature data. It is shown that the first record was made 100 years ago at Cape Khroni and at the Kazantyp Peninsula (Crimean coast). Currently, 22 reports from 18 sites have been registered along the Southern coast of the SA (17 along the Crimean coast and one at the Taman Peninsula). Treptacantha barbata (Stackh.) Orellana et Sansón (= Cystoseira barbata (Stackh.) C.Agardh) is the most widespread of the two species (17 sites). It forms dense communities with a biomass of 1.5–3.5 kg/m2. Carpodesmia crinita (Duby) Orellana et Sansón (= Cystoseira crinita Duby) was found in a small number only at two locations. It was found that the modern boundaries of the Azov fragment of the Cystoseira s. l. distribution range coincide with the boundaries of the Pre-Strait area of the SA, where salinity significantly higher, than in other areas. The distribution range has a linear configuration: it covers the Crimean coast from Cape Krasny Kut in the west to Cape Khroni in the east; is interrupted by the open water area of the Kerch Strait, and continues further on the Taman coast from Cape Achilleion to Cape Pekly. Outside the specified area, Cystoseira s. l. do not occur even if hard substrates are present. This shows, that salinity is limiting factor for the distribution of T. barbata and C. crinita in SA. In the past the system of marginal seas of the Mediterranean basin (to which SA also belongs) went through a series of transgressive and regressive phases. As a result, the boundaries, ecological conditions, and composition of biota have been changed several times in the entire basin and in its individual parts. The assumption was made that in the past Cystoseira s. l. species several times settled in the modern boundaries of the SA. The last invasion into the Pre-Strait area of SA (and inhabiting it up to the present time) should have happened in the Late Holocene 3.4–3.1 thousand years ago. Further alternation of regressions and transgressions, certainly, was accompanied by fluctuations of the distribution range boundaries, which either receded from the SA to the Kerch Strait, or again came back to its southern shores. At present, they can also fluctuate to a limited extent, following the salinity fluctuations. It is mostly relevant to the Crimean coast, where hard substrates are widespread. Considering the continuing salinization of the SA due to the climatically caused decrease in river runoff, the spread of Cystoseira s. l. species is possible on the Akmonay coast up to the top of the Arabat Bay. All this does not allow us to classify them as alien species in SA. However, in SA under modern conditions, the sustainable vegetation of the Cystoseira s. l. species with the formation of dense communities at a considerable distance from the Pre-Strait area is impossible. This must be taken into account when artificial reefs are installed and conservation strategies are developed.

scholarly journals ASSESSMENT OF THE MODERN STATE OF THE BOTTOM SEDIMENTS IN PORT TEMRYUK

2021 ◽  
Vol 49 (1) ◽  
pp. 53-67
Author(s):  
R. R. Agletdinov ◽  
I. Yu. Matasova
Keyword(s):  
Heavy Metals ◽  
Bottom Sediments ◽  
Statistical Processing ◽  
Petroleum Products ◽  
Water Area ◽  
Modern State ◽  
Sea Of Azov ◽  
The Sea Of Azov

The article analyzes the dynamics of changes in the content of petroleum products and a number of heavy metals (Fe, Cu, Zn, Pb, Cd) in the bottom sediments of the port of Temryuk in 2016–2020. Fluctuations in the concentrations of petroleum products in the soil from 88 to 413 mg/kg, iron – 8.4–41.0 mg/kg, copper – 13.6–116.0 mg/kg, zinc – 58.2–415.0 mg/kg, lead – 14.0–55.3 mg/kg, cadmium from less than 0.1 to 0.2 mg/kg were revealed. The geochemical features of the bottom sediments of the port of Temryuk relative to the sediments of the Sea of Azov are determined. Statistical processing of the obtained data made it possible to determine the correlation between the concentration of the substances in question in the soils of the studied water area.

THE MODERN MORPHODYNAMICS OF THE «AZOV TYPE» SPITSʼ COASTAL ZONE WITHIN THE LIMITS OF UKRAINE

2018 ◽  
Author(s):  
А. Давыдов ◽  
A. Davydov
Keyword(s):  
Coastal Zone ◽  
Northern Coast ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
The Past ◽  
Bank Protection ◽  
Protection Structures

Within the northern coast of the Sea of Azov there are some accumulative forms that have similar morphological, morphodynamic and lithodynamic characteristics. These forms of the sea relief united in the group of «azov type» spits. At the present time the investigated accumulative forms develop under conditions of intense erosion. The research carried out by us for the past five years, has shown that erosion of accumulative formsʼ bodies is natural, but the building of the bank protection structures affect the lithodynamic systemʼs integrity and strengthen the process.

THE IMPACT OF WIND CONDITIONS ON THE LEVELS OF TOTAL IRON CONTENT IN THE SEA OF AZOV

2017 ◽  
Author(s):  
Yuri Fedorov ◽  
Yuri Fedorov ◽  
Irina Dotsenko ◽  
Irina Dotsenko ◽  
Leonid Dmitrik ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Iron Content ◽  
Iron Concentration ◽  
Total Iron ◽  
Sea Of Azov ◽  
Open Area ◽  
The Sea Of Azov ◽  
Dissolved Iron ◽  
The Impact ◽  
Taganrog Bay

The distribution and behavior of certain of trace elements in sea water is greatly affected by both physical, chemical and hydrometeorological conditions that are showed in the scientific works of prof. Yu.A. Fedorov with coauthors (1999-2015). Due to the shallow waters last factor is one of the dominant, during the different wind situation changes significantly the dynamics of water masses and interaction in the system “water – suspended matter – bottom sediments”.Therefore, the study of the behavior of the total iron in the water of the sea at different wind situation is relevant. The content of dissolved iron forms migration in The Sea of Azov water (open area) varies from 0.017 to 0.21 mg /dm3 (mean 0.053 mg /dm3) and in Taganrog Bay from 0.035 to 0.58 mg /dm3 (mean 0.11 mg /dm3) and it is not depending on weather conditions.The reduction in the overall iron concentration in the direction of the Taganrog Bay → The Sea of Azov (open area) is observed on average more than twice. The dissolved iron content exceeding TLV levels and their frequency of occurrence in the estuary, respectively, were higher compared with The Sea of Azov (open area).There is an increase in the overall iron concentration in the water of the Azov Sea on average 1.5 times during the storm conditions, due to the destruction of the structure of the upper layer and resuspension of bottom sediments, intensifying the transition of iron compounds in the solution.

CHRONOLOGY OF CONTEMPORARY SEDIMENTATION AND POLLUTANTS ACCUMULATION IN THE BOTTOM SEDIMENTS OF THE SEA OF AZOV

2017 ◽  
Author(s):  
Andrey Kuznetsov ◽  
Andrey Kuznetsov ◽  
Yury Fedorov ◽  
Yury Fedorov ◽  
Paul Fattal ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Anthropogenic Impact ◽  
Specific Activity ◽  
Sediment Cores ◽  
Anthropogenic Pressure ◽  
Layer By Layer ◽  
Sediment Layer ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Don River

Bottom sediments formed in the water bodies under the technogenic impact are important environmental factors affecting water quality and hydrobiota. Usually they consist of natural and technogenic material and differ from natural formations by their morphology, chemical and lithological composition, physicochemical and biochemical properties. In the present paper we use the term “sediment layer of anthropogenic impact” to define the sediment layer containing technogenic material and/or chemical pollutants. The determination of its location in the sediment cores, its thickness and accumulation chronology is an important scientific problem. In the paper the results of layer by layer study of Cs-137, Am-241, Pb-210 specific activities as well as concentrations of petroleum components, lead and mercury in 48 sediment cores of the Sea of Azov and the Don River are examined. The sediment core layers are dated by radiological methods. In all the sediment cores the peak of Cs-137 specific activity related to the Chernobyl accident was detected. In the Sea of Azov, this peak is located in the upper sediment layer up to 10 cm thick, however, in the delta and in the near-delta part of the Don River, where the sedimentation rates are more important, it is found at 20 to 40 cm depth. Also in certain sediment cores the second peak of Cs-137 related to the global nuclear fallout of the 1960s was found. The most of petroleum components, lead and mercury quantities are concentrated in the upper sediment layer formed in the last 50 to 70 years, i.e. in the period of the most important anthropogenic pressure. So, this complex approach based on the data on the vertical distribution of technogenic radionuclides and common pollutants in the sediment cores made it possible to identify and delineate the sediment layer of high anthropogenic impact as well as to assess the duration of this impact.

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