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.

scholarly journals Sea level changes along the Turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean

2000 ◽  
Vol 1 (1) ◽  
pp. 141 ◽  
Author(s):  
B. ALPAR ◽  
E. DOGAN ◽  
H. YUCE ◽  
H. ALTIOK
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
Eastern Mediterranean ◽  
The Black Sea ◽  
Marmara Sea ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Sea Level Fluctuations ◽  
Short Period ◽  
Turkish Straits System

Short, tidal, subtidal, seasonal, secular sea-level variations, sea-level differences and interactions between the basins have been studied, based on the data collected at some permanent and temporary tide gauges located along the Turkish coasts, mostly along the Straits connecting the Marmara Sea to outer seas. Even though the deficiency of sufficient information prevented us to reach the desired results, many pre-existed studies have been improved. Short-period oscillations were clearly identified along the Turkish Strait System and related to their natu-ral periods. The tidal amplitudes are low along the Turkish coasts, except northern Aegean and eastern Mediterranean. The stability of harmonic constants of Samsun and Antalya were examined and most of the long period constituents were found to be unstable. Even the Marmara Sea is not affected from the tidal oscillations of Black and Aegean Seas, some interactions in low frequency band have been detected. Subtidal sea level fluctuations (3-14 day) have relations with the large-scale cyclic atmospheric patterns passing over the Turkish Straits System. Short-term effects of wind on sea level are evident.Seasonal sea-level fluctuations along the Turkish Straits System are in accord with Black Sea's hydrological cycle. The differential range of the monthly mean sea levels between the Black Sea and the Marmara Sea is highly variable; high during spring and early summer and low during fall and winter.On the average, there is a pronounced sea-level difference (55 cm) along the Turkish Straits System. However, the slope is nonlinear, being much steeper in the Strait of Istanbul. This barotrophic pressure difference is one of the most important factors causing the two-layer flow through the system. The topography and hydrodynamics of the straits, the dominant wind systems and their seasonal variations make this flow more complicated. For secular sea level changes, a rise of 3.2 mm/a was computed for Karsiyaka (1935-71) and a steady trend (-0.4 mm /a) has been observed for annual sea levels at Antalya (1935-77). The decreasing trend (-6.9 mm/a) at Samsun is contrary to the secular rising trend of the Black Sea probably because of its rather short monitoring period (1963-77).

scholarly journals Release of Gases in the Seas and Oceans

2021 ◽  
pp. 194-201
Author(s):  
Shota Mestvirishvili ◽  
◽  
Irina Denisova ◽  
Alexsandre Babunashvili ◽  
◽  
...  
Keyword(s):  
Black Sea ◽  
Environmental Changes ◽  
Oil Fields ◽  
The Black Sea ◽  
Environmental Study ◽  
Gas Flows ◽  
The Caspian Sea ◽  
Gas Emissions ◽  
Research Ship ◽  
Black Sea Coast

Over the recent decades, gas and oil fields have been intensively explored in the seas and oceans of the world. As part of the expedition of the Ukrainian research ship "Professor Vodyanitsky", gas flows from the bottom of the Black sea of the continental shoal located on the territory of Georgia were studied. In this article, we conducted an environmental study of the results obtained during the expedition. The analysis revealed the dangers that gas emissions found in this region may pose. The article presents map of the coastal shelf of Adjara with gas release points; Similar places of gas emissions on the black sea coast of Crimea are discussed; The results of gas extraction in the Caspian sea are presented; The nature of environmental changes caused by the removal of a layer of hydrogen sulfide from the sea depths to the upper layers of the sea during a gas eruption is analyzed.

scholarly journals Hydrology and circulation in the North Aegean (eastern Mediterranean) throughout 1997 and 1998

2002 ◽  
Vol 3 (1) ◽  
pp. 5 ◽  
Author(s):  
V. ZERVAKIS ◽  
D. GEORGOPOULOS
Keyword(s):  
Surface Layer ◽  
Black Sea ◽  
Sea Water ◽  
Saline Water ◽  
Eastern Mediterranean ◽  
Late Summer ◽  
Cyclonic Circulation ◽  
The Black Sea ◽  
The North ◽  
North Aegean

The combination of two research projects offered us the opportunity to perform a comprehensive study of the seasonal evolution of the hydrological structure and the circulation of the North Aegean Sea, at the northern extremes of the eastern Mediterranean. The combination of brackish water inflow from the Dardanelles and the sea-bottom relief dictate the significant differences between the North and South Aegean water columns. The relatively warm and highly saline South Aegean waters enter the North Aegean through the dominant cyclonic circulation of the basin. In the North Aegean, three layers of distinct water masses of very different properties are observed: The 20-50 m thick surface layer is occupied mainly by Black Sea Water, modified on its way through the Bosphorus, the Sea of Marmara and the Dardanelles. Below the surface layer there is warm and highly saline water originating in the South Aegean and the Levantine, extending down to 350-400 m depth. Below this layer, the deeper-than-400 m basins of the North Aegean contain locally formed, very dense water with different θ /S characteristics at each subbasin. The circulation is characterised by a series of permanent, semi-permanent and transient mesoscale features, overlaid on the general slow cyclonic circulation of the Aegean. The mesoscale activity, while not necessarily important in enhancing isopycnal mixing in the region, in combination with the very high stratification of the upper layers, however, increases the residence time of the water of the upper layers in the general area of the North Aegean. As a result, water having out-flowed from the Black Sea in the winter, forms a separate distinct layer in the region in spring (lying between “younger” BSW and the Levantine origin water), and is still traceable in the water column in late summer.

scholarly journals Pleistocene Sea Levels possibly indicated by Buried Black Sediments in the Black Sea

Nature ◽  
1970 ◽  
Vol 227 (5259) ◽  
pp. 700-700 ◽  
Author(s):  
ROBERT A. BERNER
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Sea Levels

Meiobenthos as indicator of gaseous hydrocarbons reservoirs existing under the seabed of the Black Sea

2021 ◽  
Author(s):  
Valentina Yanko ◽  
Anna Kravchuk ◽  
Irina Kulakova ◽  
Tatiana Kondariuk
Keyword(s):  
Black Sea ◽  
Abiotic Factors ◽  
Taxonomic Composition ◽  
The Black Sea ◽  
Northwestern Part ◽  
Hydrocarbon Gases ◽  
The Sustainable Development ◽  
Dual Analysis ◽  
Gaseous Hydrocarbons ◽  
Physical And Chemical

<p>This <span>presentation</span> represents a case study that reviews research into the relationship between meiobenthos distribution and concentrations of hydrocarbon gases (HG), primarily methane, in the sediments of the northwestern part of the Black Sea, including gases released by mud volcanoes and gas seeps. Evidence forming the basis of this research comes from meiobenthos here represented by 29 species of benthic foraminifers, 7 species of ostracods, and 44 species of nematodes. The potential use of these meiobenthic organisms as indicators of gaseous hydrocarbons reservoirs existing under the seabed is evaluated according to two linked axes, namely the dual analysis of abiotic factors (physical and chemical parameters of the water column, gasmetrical, geochemical, lithological, and mineralogical properties of the sediments) and biotic characteristics (quantitative and taxonomic composition of foraminifers, nematodes, and ostracods). Studies of this kind have been directed toward developing interdisciplinary methods to improve the search for HG accumulations, especially methane, under the seabed. Development of such methods might have substantial socio-economic importance for the economy of Ukraine as well as that of other Black Sea countries, and such methods might also contribute to the sustainable development of Black Sea ecosystems.</p>

scholarly journals Key Environmental Factors Controlling Planktonic Foraminiferal and Pteropod Community’s Response to Late Quaternary Hydroclimate Changes in the South Aegean Sea (Eastern Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 709
Author(s):  
Christina Giamali ◽  
George Kontakiotis ◽  
Efterpi Koskeridou ◽  
Chryssanthi Ioakim ◽  
Assimina Antonarakou
Keyword(s):  
Environmental Factors ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Explanatory Power ◽  
Principal Component ◽  
Aegean Sea ◽  
Late Glacial ◽  
The South

A multidisciplinary study was conducted in order to investigate the environmental factors affecting the planktonic foraminiferal and pteropod communities of the south Aegean Sea. Aspects of the Late Quaternary paleoceanographic evolution were revealed by means of quantitative analyses of planktonic foraminiferal and pteropod assemblages (including multivariate statistical approach; principal component analysis (PCA)), the oxygen (δ18O) and carbon (δ13C) isotopic composition of planktonic foraminifera and related paleoceanographic (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), seasonality) indices, extracted by the gravity core KIM-2A derived from the submarine area between Kimolos and Sifnos islands. Focusing on the last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel sublayers S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP), with extremely warm and stratified conditions. Pteropod fauna during the sapropel deposition were recorded for the first time in the south Aegean Sea, suggesting arid conditions towards the end of S1a. Besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, water column stratification, primary productivity, and seasonality also control their communities during the Late Quaternary.

Sign in / Sign up

Export Citation Format

Share Document