scholarly journals Origin, migration pathways, and paleoenvironmental significance of Holocene ostracod records from the northeastern Black Sea shelf

2017 ◽  
Vol 87 (1) ◽  
pp. 49-65 ◽  
Author(s):  
Maria A. Zenina ◽  
Elena V. Ivanova ◽  
Lee R. Bradley ◽  
Ivar O. Murdmaa ◽  
Eugene I. Schornikov ◽  
...  
Keyword(s):  
Black Sea ◽  
Sediment Cores ◽  
Early Holocene ◽  
The Black Sea ◽  
Mediterranean Species ◽  
Species Occurrence ◽  
Additional Information ◽  
Modern Species ◽  
Migration Pathways ◽  
Ostracod Species

AbstractMicropaleontological studies of the Black Sea, including ostracod records, have suggested that early Holocene salinity values were between ~5 and 10 practical salinity units (psu), contrasting with present values of 18–22 psu. However, more precise paleoenvironmental reconstructions based on ostracod assemblages require additional information related to their modern ecological affinities. This study uses modern species information collected from samples with living fauna to interpret the fossil Holocene assemblages of two sediment cores, Ak-2575 and Ak-521, collected from the northeastern outer shelf of the Black Sea. A total of 37 ostracod species are recorded in the fossil assemblages, with 2 related to freshwater/oligohaline environments, 23 from Caspian-type environments, and 12 from environments similar to the Mediterranean. Three distinct assemblage zones are identified from the Caspian type dominating in the early Holocene up to 7.4 cal ka BP, a mixed assemblage of Caspian type and Mediterranean type from 7.4 to 6.8 cal ka BP, and a progressive dominance of Mediterranean species from 6.8 cal ka BP. It is very likely that the dominant control of ostracod species occurrence during the period up to ~6.8 cal ka BP is salinity. A range of factors including temperature, biotope, and sedimentation rates influenced the species distribution over the last 6.8 cal ka BP.

Black Sea Shores of Ukraine

2008 ◽  
Author(s):  
Yu.P. Zaitsev ◽  
Keyword(s):  
Natural Resources ◽  
Black Sea ◽  
Coastal Wetlands ◽  
The Black Sea ◽  
Additional Information ◽  
Annotated List ◽  
Geological Past ◽  
Black Sea Coast ◽  
Independent Observations ◽  
Sea Coast

The book covers the geological past of the Black Sea, physical-geographical and ecological characteristics, coastal wetlands of the northern part of the Black Sea, its natural resources. Much attention is paid to the problems of ecology and protection of the Black Sea. Additional information is presented for tourists, recommendations for conducting independent observations of the ecology of the Black Sea coastal zone, as well as an annotated list of fish species on the Ukrainian Black Sea coast for fishing enthusiasts. The publication is illustrated with original color photographs, drawings and diagrams.

Was the Black Sea catastrophically flooded in the early Holocene?

2009 ◽  
Vol 28 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
Liviu Giosan ◽  
Florin Filip ◽  
Stefan Constatinescu
Keyword(s):  
Black Sea ◽  
Early Holocene ◽  
The Black Sea

Mn(II) carbonate authigenesis marks the benthic SMTZ and is fueled by Mn-driven anaerobic oxidation of methane: A Black Sea evidence

2021 ◽  
Author(s):  
Tiantian Sun ◽  
Michael E Böttcher ◽  
Jens Kallmeyer ◽  
Tina Treude ◽  
Marko Lipka ◽  
...  
Keyword(s):  
Pore Water ◽  
Black Sea ◽  
Dissolved Inorganic Carbon ◽  
Sediment Cores ◽  
The Black Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Potential Contribution ◽  
Anaerobic Oxidation ◽  
Upward Migration ◽  
Geochemical Composition

<p>In the Black Sea, sediment cores covering the last brackish-limnic transition were recovered and investigated for anaerobic biogeochemical processes controlling sulfur, carbon, and metal cycling. The development of a sulfate-methane transition zone (SMTZ) is nowadays found below the brackish zone in the limnic part of the sediments that limits the upward migration of biogenic methane into surface sediments and the water column. The position of the SMTZ may have changed in the past due to dynamic fluxes of dissolved species in the pore water. Besides dissolved sulfate, metal-bearing minerals have been shown to serve as potential reactants, also converting CH<sub>4</sub> into dissolved inorganic carbon (DIC). The pore water and sediment stable isotope (C, S, O) and geochemical composition were investigated, as well as in-situ microbial rates of sulfate reduction and total anaerobic oxidation of CH<sub>4</sub> (AOM) obtained from sediment incubations for the identification of a potential contribution of manganese-bearing minerals to AOM in the limnic part of the sediments (Mn-AOM). In the limnic Black Sea sediments Mn-AOM is causes an upward flux of dissolved Mn whereas intense SO<sub>4</sub>-AOM located in shalower sediments leads to an increase in pH and a maximum in DIC concentrations in the SMTZ. The resulting change in saturation states leads to the precipitation of mixed MnCa-carbonate solid-solutions (‘rhodochrozitization front’) and the development of a zone enriched in excess sedimentary Mn(II). We further argue that these authigenic fronts may survive changes in pore water composition and are stable in the anoxic sedimentary record, marking the position of paleo-SMTZs. The persisting formation of this geochemical marker has advantage in application over the transient development of a sulfidization front of metastable mackinawite, that is fromed by the reaction of downard migrating sulfide with upward diffusing Fe(II), originating from SO<sub>4</sub>-AOM and Fe-AOM, respectively.</p>

scholarly journals The Holocene history of the NE Black Sea and surrounding areas: An integrated record of marine and terrestrial palaeoenvironmental change

The Holocene ◽  
2019 ◽  
Vol 29 (4) ◽  
pp. 648-661 ◽  
Author(s):  
Fabienne Marret ◽  
Lee R Bradley ◽  
Pavel E Tarasov ◽  
Elena V Ivanova ◽  
Maria A Zenina ◽  
...  
Keyword(s):  
Black Sea ◽  
Deciduous Forest ◽  
Land Use Changes ◽  
Water Environment ◽  
Early Holocene ◽  
The Black Sea ◽  
Pollen Record ◽  
Temperate Deciduous Forest ◽  
Black Sea Region ◽  
Palaeoenvironmental Change

Here we present an almost complete and integrated Holocene record of marine and terrestrial palaeoenvironmental change from the NE shelf of the Black Sea. A dinoflagellate cyst record used to reconstruct Holocene sea-surface conditions highlights that the NE shelf was a brackish water environment, with a minimum salinity of 7 psu in the early-Holocene before changing at a gradual rate to a more saline environment with maximum salinities of ~18 psu being reached around 3 cal. ka. A warming phase was detected from 6 cal. ka BP, with warmest conditions between 3 and 2.5 cal. ka BP. A pollen record is used to examine the major climate and land-use changes in the eastern Black Sea region. Biome reconstructions show that the temperate deciduous forest dominates throughout the record, although with an overall decline. From early-Holocene to the first hiatus around ~9 cal. ka BP, Pinus pollen dominates, while taxa representing a mixed oak-hornbeam-beech forest are less abundant, indicating relatively cool and dry conditions. Between ~7.9 and ~6.1 cal. ka BP, a thermophilous deciduous forest established, suggesting an overall warming trend and humid conditions. From 4 cal. ka BP, Pinus dominates the pollen record, accompanied by an increase of herbs, implying an opening of the landscape, which would coincide with the beginning of the Meghalayan Age. The integrated record of the marine and terrestrial climate indicators supports the notion that this change in landscape may have been triggered by a combination of warmer and drier conditions and human activities in this region.

scholarly journals OIL POLLUTION OF THE BLACK SEA COAST IN THE AREAS OF THE TSEMES BAY AND THE KERCH STRAIT: LONG-TERM DYNAMICS AND ASSESSMENT OF SELF-CLEANING CAPACITY

2021 ◽  
Vol 49 (1) ◽  
pp. 142-162
Author(s):  
A. N. Kuznetsov ◽  
E. V. Kuznetsova
Keyword(s):  
Black Sea ◽  
Oil Pollution ◽  
Sediment Cores ◽  
Environmental Parameters ◽  
The Black Sea ◽  
Kerch Strait ◽  
Black Sea Coast ◽  
Tar Balls ◽  
High Level ◽  
Sea Coast

The paper examines the results of twelve-year (2007 to 2019) observations of spatial distribution and temporal changes in the concentrations of petroleum components in the coastal waters and sediment cores, as well as in the quantity and composition of oil slicks and tar balls on the beaches, cliffs and solid constructions of the Black Sea coast in the area of the city of Novorossiysk, which is the most important oil seaport of Russia, and in the Kerch Strait. 165 samples of seawater, 24 sediment cores up to 50 cm long split layer-bylayer into 108 samples, and 102 samples of oil slicks and tar balls were taken and analyzed with the use of thin layer and column chromatography, optical and gravimetric methods. The evidences of high level and chronic character of oil pollution of the studied coastal sectors are presented. Much attention is given to the dynamics of the natural transformation of oil slicks and tar balls found on the shore. It is shown that over time, under the influence of natural factors of attenuation, the oil slicks stranded ashore undergo an exponential decrease of the ratio between relatively labile hydrocarbons and conservative asphaltic components in their composition. The rate of the process may vary considerably depending on the size of oil pollution traces, their location on the coastal zone profile, as well as on the climatic, hydrological, and geomorphological conditions. An empirical statistical model is developed on the base of this data. This model makes it possible to classify and to map seacoasts according to their ability to degrade oil pollution using the information on the principal environmental parameters of attenuation.

scholarly journals DYNAMICS OF DEVELOPMENT OF LITHOFLUID OIL AND GAS SYSTEMS IN THE CRETACEOUS DEPOSITS OF THE WESTERN CENTRICLINAL OF THE BLACK SEA MEGADEPRESSION

2021 ◽  
pp. 83-89
Author(s):  
K. Hryhorchuk ◽  
V. Hnidets ◽  
Z. Wojcickyu
Keyword(s):  
Black Sea ◽  
Structural Changes ◽  
Oil And Gas ◽  
Structural Features ◽  
The Black Sea ◽  
Gas Accumulation ◽  
Spatio Temporal ◽  
And Migration ◽  
Migration Pathways ◽  
Cretaceous Deposits

On the basis of modeling the dynamics of the catagenesis of the Cretaceous deposits, the lateral heterogeneity of the history of their catagenesis within the western part of the Black Sea megadepression, caused by the tectonic regime of the blocks separated by the Golitsyn, Sulino-Tarkhankutsky, Gubkino-Donuzlavsky sublatitudinal faults, was established. The spatio-temporal features of the development of reservoirs and migration paths of hydrocarbon fluids have been established, the predicted zones of oil and gas accumulation have been localized. There are four types of lithogenetic reservoirs, which differed in the time of formation, structural features, fluid regime and the nature of oil and gas saturation.In the first cycle of catagenesis, the generation center was localized mainly in the sediments of the Lower Albian (t 80–100 оС), in the second – the Middle Albian (t 100–120 оС), in the third – the Upper Albian (t 130–150 оС).Given a certain difference in the situations of sedimentation of these stratigraphic units, the composition and content of scattered organic matter in the sediments were different. This, as well as the different generation temperatures, obviously caused the specific composition of hydrocarbon fluids formed during individual cycles of catagenesis. Along the migration pathways and during structural changes, these fluids were mixed, multicomponent systems were formed, and the composition of hydrocarbons changed.The possibility of the existence of subvertical "vein" areas of oil and gas accumulation with a width of up to 10 km and a height of 1,5–2,0 km is argued. Such reservoirs, on the one hand, may contain deposits and, on the other hand, supply hydrocarbons to overlying traps. Given the nature of oil and gas accumulation, the potential resources and, consequently, the prospects for oil and gas in the region can be much higher.

scholarly journals Late Pleistocene to Recent ostracod assemblages from the western Black Sea

2010 ◽  
Vol 29 (2) ◽  
pp. 119-133 ◽  
Author(s):  
Ian Boomer ◽  
Francois Guichard ◽  
Gilles Lericolais
Keyword(s):  
Black Sea ◽  
Environmental Changes ◽  
Eastern Mediterranean ◽  
Initial Step ◽  
Late Glacial ◽  
Taxonomic Composition ◽  
Early Holocene ◽  
The Black Sea ◽  
The Caspian Sea ◽  
Sea Levels

Abstract. During the last glacial phase the Black Sea basin was isolated from the world's oceans due to the lowering of global sea-levels. As sea-levels rose during the latest glacial and early Holocene period, the Black Sea was once again connected to the eastern Mediterranean via the Dardanelles–Marmara–Bosporus seaway. In recent years, trace element and stable isotope analyses of ostracod assemblages have yielded important details regarding the hydrological evolution of the Black Sea during these events. Despite this focus on the geochemical signatures of the ostracods, little if any attention has been paid to the taxonomic composition of the ostracod assemblages themselves and there are notably few publications on the sub-littoral fauna of this important water body. We present a summary of the most abundant ostracod taxa of the Black Sea during the late glacial to early Holocene phase (dominated by the Candonidae, Leptocytheridae and Loxoconchidae) and chart their response to the subsequent environmental changes in the early Holocene with the pre-connection, low salinity ‘lacustrine’ fauna being replaced by one with a more Mediterranean aspect. Many of these taxa are illustrated using SEM for the first time, providing an important initial step in establishing taxonomic stability within Black Sea ostracod studies and noting faunal similarities with neighbouring areas, such as the Caspian Sea.

Early Holocene Marine Flooding of the Black Sea

2000 ◽  
Vol 54 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Elazar Uchupi ◽  
David A. Ross
Keyword(s):  
Black Sea ◽  
Early Holocene ◽  
The Black Sea ◽  
Sea Of Marmara ◽  
Bottom Currents ◽  
Continental Rise ◽  
Catastrophic Flood ◽  
A Chain ◽  
Echo Sounding

Echo-sounding data recorded in the Black Sea in 1969 imaged a chain of hills 5- to 150-m high at a depth of 2000–2200 m that resemble hills on the lower continental rise. Like those hills, the features in the western Black Sea may have been created by bottom currents. The easterly flowing currents inferred to have formed the hills may be related to a catastrophic flood of the Black Sea from the Sea of Marmara 7150 yr ago.

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