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.

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.

Artificial radionuclides, mercury, lead, and oil components in sediment cores as markers of the Anthropocene Epoch

2021 ◽  
Author(s):  
Yury Fedorov ◽  
Andrey Kuznetsov ◽  
Irinageo Dotsenko ◽  
Anna Mikhailenko
Keyword(s):  
Bottom Sediments ◽  
Working Group ◽  
Anthropogenic Impact ◽  
Sediment Cores ◽  
Water Bodies ◽  
Sedimentation Rates ◽  
Sea Of Azov ◽  
The Holocene ◽  
The Sea Of Azov ◽  
Oil Components

<p>The majority of researches of the Working group on the ‘Anthropocene’ of the International Commission on Stratigraphy (ICS) voted for the recognition of the Anthropocene as a formal chrono-stratigraphic unit characterized by profound alterations of several conditions and processes on Earth by human impact. It is also proposed to place its beginning and the end of the Holocene epoch in the mid-20th century, coinciding with the launch of nuclear weapon tests [1]. In contemporary sediment cores of the Sea of ​​Azov, the Don and the Kuban rivers, we will distinguish a "layer of anthropogenic impact", meaning the layer containing considerable quantities of technogenic material and (or) pollutants [2]. To reveal the chronology of its formation, its thickness, and boundaries, it is proposed to use the results of layer-by-layer determining of the Cs-137 and Am-241 specific activities, as well as the content of oil components, lead and mercury in the bottom sediments of the water bodies. The upper Cs-137 peak formed due to the Chernobyl accident and sometimes the lower Cs-137 and Am-241 peaks related to the global radioactive fallout in the 1950s and 1960s have been detected [3]. The decrease of mercury, lead, and oil components concentrations from the upper to the lower parts of sediment cores has also been observed. The results of analysis of technogenic radionuclides and priority pollutants distribution have proved that since the 1950s and 1960s in the bottom sediments of the Sea of ​​Azov and water bodies of its basin the “layer of anthropogenic impact" has been being formed. Its thickness varies from 20 to 50 cm and may even exceed 50 cm in areas characterized by high sedimentation rates. It has been found out that in the mid-20th century the ecosystem of the Sea of ​​Azov began to suffer from intense anthropogenic pressure, which reached its maximum in the 1970s and 1980s. It is proposed to consider the studied pollutants (technogenic radionuclides, mercury, lead, and oil components) as a possible set of priority markers of the Anthropocene epoch. The Holocene - Anthropocene boundary should be placed at the base of the identified “layer of anthropogenic impact”.</p><p> </p><p>The research was supported by the Russian Foundation for Basic Research, project no. 19-05-50097.</p><p> </p><p>Bibliography</p><p>[1] Working Group on the ‘Anthropocene’. Results of binding vote by AWG. http://quaternary.stratigraphy.org/working-groups/anthropocene/ (last accessed 17 January 2021).</p><p>[2] Kuznetsov A.N., Fedorov Yu.A., and Yaroslavtsev V.M. (2018) Technogenic and natural radionuclides in the bottom sediments of the Sea of Azov: regularities of distribution and application to the study of pollutants accumulation chronology. IOP Conference Series: Earth and Environmental Science 107, 012063.</p><p>[3] Fedorov Yu.A., Kuznetsov A.N., and Trofimov M.E. (2008) Sedimentation rates in the Sea of Azov inferred from Cs-137 and Am-241 specific activity. Doklady Earth Sciences, vol. 423, no. 1, pp. 1333-1334.</p>

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

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.

scholarly journals Spiders (Aranei) of the coast of Taganrog Bay (the Sea of Azov) and the Don River delta

2016 ◽  
Vol 12 (1) ◽  
pp. 3-28 ◽  
Author(s):  
A.V. Ponomarev ◽  
◽  
E.V. Prokopenko ◽  
P.P. Ivliev ◽  
V.Yu. Smatko ◽  
...  
Keyword(s):  
River Delta ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Don River ◽  
Taganrog Bay

scholarly journals First find of the Black Sea turbot Scophthalmus maeoticus (Scophthalmidae) in Don River estuary

2018 ◽  
Vol 3 (3) ◽  
pp. 70-76
Author(s):  
D. N. Kutsyn ◽  
A. V. Startsev
Keyword(s):  
River Estuary ◽  
The Black Sea ◽  
Anadromous Fish ◽  
Published Data ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Don River ◽  
Brackish Water Species ◽  
Taganrog Bay ◽  
Water Species

The aim of the work was to describe the first catch of Scophthalmus maeoticus (Pallas, 1814) in the Don River estuary (47°3′57′′N, 39°12′39′′E) and to analyze it in the context of salinity increasing in the Sea of Azov. The study was carried out using two turbot specimens caught on July 16, 2016, and on September 1, 2016, by a net with a mesh 55 mm. Assessment of the chalinic conditions of the Sea of Azov was carried out through annual monitoring at 3 hydrometeorological stations in Don River delta and in the eastern part of the Taganrog Bay. The article presents main meristic and plastic features of the turbots studied in comparison with published data. The dynamics of the salinity in the Sea of Azov and in the Taganrog Bay is analyzed. Find of the turbot in the estuary of the Don River is an evidence of ichthyocene transformation in response to salinity increasing (up to 12.5 ‰ in the Sea of Azov and up to 6 ‰ in the Taganrog Bay). The first catch of the turbot corresponds with trend of increasing of marine and brackish-water species share and with a decrease in the number of native semi-anadromous fish species.

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