scholarly journals Basic Features of the Black Sea Late Cenozoic History Based on Results of Deep-Sea Drilling, Leg42B

1978 ◽  
Author(s):  
M.V. Muratov ◽  
Y.P. Neprochnov ◽  
D.A. Ross ◽  
E.S. Timonis
Keyword(s):  
Black Sea ◽  
Deep Sea ◽  
The Black Sea ◽  
Late Cenozoic ◽  
Basic Features

scholarly journals Biogeochemical characteristics of shallow methane seeps of Crimean coastal areas in comparison with deep-sea seeps of the Black Sea

2020 ◽  
Vol 5 (4) ◽  
pp. 37-55
Author(s):  
T. V. Malakhova ◽  
V. N. Egorov ◽  
L. V. Malakhova ◽  
Yu. G. Artemov ◽  
N. V. Pimenov
Keyword(s):  
Black Sea ◽  
Deep Sea ◽  
Coastal Areas ◽  
The Black Sea ◽  
Gas Bubble ◽  
Gas Emission ◽  
Bacterial Mats ◽  
Seabed Sediments ◽  
Gas Seeps ◽  
Methane Carbon

Methane gas bubble emissions (seeps) are widespread phenomenon in the World Ocean, inter alia in Black Sea basin. The relevance of the research of methane seeps is due to their important role as a source of methane – greenhouse and environment-forming gas – for water column and atmosphere. The article presents a comparative analysis of the data from our biogeochemical 10-year studies of shallow gas seeps of the Crimean Peninsula and data on deep-sea gas seeps of the Black Sea. During 10-year period, apart from carrying out hydroacoustic research, the following parameters were determined: bubble gas component composition, methane carbon isotopic composition, microbial community structure of bacterial mats, covering gas bubble emission sites, and gas fluxes from separate seeps. During long-term monitoring, 14 separate gas bubble emission sites were detected and described in Crimean coastal areas; they were located from Cape Tarkhankut in the west of the peninsula to the Dvuyakornaya Bay in the southeast. Crimean coastal seeps were mostly of biogenic origin, with a seasonal type of gas bubble emission. Laspi Bay seeps were classified as emissions of deep gas of thermocatalytic genesis. A significant variation was recorded in values of isotopic composition of methane carbon δ13C-CH4 of bubble gas in coastal shallow areas (−94…−34 ‰), which indicates different conditions for bubble gas generation and maturation in seabed sediments. Similar to deep-sea seeps, coastal gas bubble emissions were accompanied by bacterial mats of diverse structure, with different dominating species. As shown, formation of stable bacterial biomass, usually consisting of sulfide- and sulfur-oxidizing bacteria, requires a fluid flux of reduced dissolved gases, while pointwise bubble gas discharge does not provide sufficient concentration gradients and can mechanically disrupt community structure. Various methods were used to estimate the size spectra of bubbles, as well as fluxes from separate seeps. Gas flux values varied from 1.8 L·day−1 (the Martynova Bay) to 40 L·day−1 (the Laspi Bay). The environment-forming effects, related to gas bubble emission in coastal areas, are discussed: effect of seeps on oxygen conditions in seabed sediments and in water column above gas emission sites, vertical water mixing due to gas lift effect, and fluid discharge at gas emission sites.

IN SITUPRESERVATION OF A DEEP-SEA WRECK SITE : SINOP D IN THE BLACK SEA

2010 ◽  
Vol 55 (sup2) ◽  
pp. 6-11 ◽  
Author(s):  
Dennis Piechota ◽  
Robert D. Ballard ◽  
Bridget Buxton ◽  
Michael Brennan
Keyword(s):  
Black Sea ◽  
Deep Sea ◽  
The Black Sea

scholarly journals Geochemistry of Late Cenozoic Sediments of the Black Sea, Leg 42B

1978 ◽  
Author(s):  
E. Emelyanov ◽  
A.P. Lisitzin ◽  
K.M. Shimkus ◽  
E.S. Trimonis ◽  
V.K. Lukashev ◽  
...  
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Late Cenozoic ◽  
Cenozoic Sediments

Double Diffusive Intrusions, Mixing and Deep Sea Convection Processes in the Black Sea

1991 ◽  
pp. 17-42 ◽  
Author(s):  
Emin Özsoy ◽  
Zafer Top ◽  
George White ◽  
James W. Murray
Keyword(s):  
Black Sea ◽  
Deep Sea ◽  
The Black Sea ◽  
Double Diffusive

Late Pleistocene – Holocene sea level and climate changes in the Black Sea

2020 ◽  
Author(s):  
Andrei Briceag ◽  
Gabriel Ion ◽  
Mihaela Melinte-Dobrinescu ◽  
Dan Vasiliu ◽  
Naliana Lupascu
Keyword(s):  
Last Glacial Maximum ◽  
Black Sea ◽  
Deep Sea ◽  
Emiliania Huxleyi ◽  
Glacial Maximum ◽  
The Black Sea ◽  
Calcareous Nannoplankton ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>The Danube Deep-Sea Fan, situated in NW Black Sea, is one of the most developed deep-sea sedimentary structures in Europe (Panin & Jipa, 2002). In 2018, in the framework of the uBiogas Project (24PCCDI/2018), several cores were acquired from the aforementioned area. In this study, high resolution microfaunal analyses coupled with sedimentological and geochemical ones, were performed on two gravity cores that revealed changes since the Last Glacial Maximum. The cores have been collected from two secondary canyons, situated in the E of the Danube Canyon, at 655,7 m (MN183_3_GC_1) and 1315 m water depths (MN183_8_GC_1). In both cores, three stratigraphic units as described by Ross & Degens (1974) were identified (oldest first): Unit 3 (Lacustrine lutite), Unit 2 (Sapropel Mud) and Unit 1 (Coccolith Mud).</p><p>The sediments of Unit 3 correspond to the Last Glacial Maximum and are marked by the presence of the cold-water ostracod species. The cores contain a reddish-brown clay and silty interval belonging to the post-glacial melt-water pulse of the Heinrich Event 1. In these deposits the ostracod assemblages display a high diversity and abundance. The CaCO<sub>3</sub> amount is very low, i.e. below 15%, except for the upper part where it reaches more than 50%. The samples of Unit 3 contain nannofossil assemblages that are entirely composed of reworked species from Cretaceous, Paleogene, Early and Middle Miocene intervals.</p><p>In Unit 2 (the sapropel), very few specimens of ostracods were identified, towards the top. During this depositional interval CaCO<sub>3 </sub>values are dropping again below 15%. The high abundance of the calcareous nannoplankton species Braarudosphaera bigelowii in the upper part of Unit 2 suggests the first strong influx of marine waters into the Black Sea basin.</p><p>In the youngest Unit 1, a brackish-marine ostracod assemblage, with low diversity and abundance was identified. This interval is characterized by the presence of polyhaline ostracods with Mediterranean origin. The ostracods from this assemblage tolerate salinities comprised between 17-21 ‰ and characterize a sub-littoral environment. The CaCO<sub>3</sub> values are increasing to more than 50%. During the depositional interval of Unit 1 the environmental was definitely a marine one, probably with a constant salinity of surface waters over 17 ppm, allowing the calcareous nannoplankton species Emiliania huxleyi and Braarudosphaera bigelowii to proliferate. The great abundance of the two taxa and especially of Emiliania huxleyi indicates the existence in the basin of a high nutrient input.</p><p>The financial support for this paper was provided by the Romanian Ministry of Research and Innovation, through the Programme 1 – Development of the National System of Research – Institutional Performance, Project of Excellence in Research-Innovation, Contract No. 8PFE/2018 and by the Project uBiogas, contract no. 24PCCDI/ 2018.</p><p> </p><p>Panin, N., Jipa, D., 2002. Danube river sediment input and its interaction with the northwestern Black Sea. Estuarine Coastline Shelf Science 54: 551–562.</p><p>Ross, D.A., Degens, E.T., 1974. Recent sediments of the Black Sea. In: Degens E.T. and Ross D.A. (Eds.), The Black Sea: Geology, Chemistry, and Biology. American Association of Petroleum Geologists, Tulsa, USA: 183–199.</p>

scholarly journals Factors and criteria of the morphostructural zoning and the main types of morphostructures of the North-West of the Black Sea

2019 ◽  
pp. 68-82
Author(s):  
А. А. Pasynkov ◽  
B. A. Vakhrushev
Keyword(s):  
Continental Slope ◽  
Black Sea ◽  
Deep Sea ◽  
Wave Action ◽  
The Black Sea ◽  
North West ◽  
The North ◽  
Research Techniques ◽  
Morphostructural Zoning

The principles of morphostructural zoning are presented on the example of the North-West of the Black Sea. Research techniques and criteria for distinguishing the morphostructural regions are discussed. In the morphostructural province of the Black Sea the following subprovinces were identified: shelf under conditions of active and passive wave action, continental slope with non-wave accumulation, deep-sea depression. Fragment of the map of morphostructural zoning of the North-West of the Black Sea at 1:500 000 scale is presented. Main morphogenetic types of morphostructures of the shelf, continental slope and deep sea basin of the Black sea are given. The characteristics of the selected morphostructural taxa are described.

scholarly journals Regulation of anaerobic methane oxidation in sediments of the Black Sea

2008 ◽  
Vol 5 (3) ◽  
pp. 2305-2341 ◽  
Author(s):  
N. J. Knab ◽  
B. A. Cragg ◽  
E. R. C. Hornibrook ◽  
L. Holmkvist ◽  
C. Borowski ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Methane Oxidation ◽  
Black Sea ◽  
Deep Sea ◽  
The Black Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Oxidation Of Methane ◽  
History Of ◽  
Carbon Recycling ◽  
Sulfate Reduction Rates

Abstract. Anaerobic oxidation of methane (AOM) and sulfate reduction (SRR) were investigated in sediments of the western Black Sea, where methane transport is controlled by diffusion. To understand the regulation and dynamics of methane production and oxidation in the Black Sea, rates of methanogenesis, AOM, and SRR were determined using radiotracers in combination with pore water chemistry and stable isotopes. On the shelf of the Danube paleo-delta and the Dnjepr Canyon, AOM did not consume methane effectively and upwards diffusing methane created an extended sulfate-methane transition zone (SMTZ) that spread over more than 2.5 m and was located in formerly limnic sediment. Measurable AOM rates occurred mainly in the lower part of the SMTZ, sometimes even at depths where sulfate seemed to be unavailable. The inefficiency of methane oxidation appears to be linked to the limnic history of the sediment, since in all cores methane was completely oxidized at the limnic-marine transition. The upward tailing of methane was less pronounced in a core from the deep sea in the area of the Dnjepr Canyon, the only station with a SMTZ close to the marine deposits. Sulfate reduction rates were mostly extremely low, and in the SMTZ were even lower than AOM rates. Rates of bicarbonate-based methanogenesis were below detection limit in two of the cores, but δ13C values of methane indicate a biogenic origin. The most depleted δ13C-signal was found in the SMTZ of the core from the deep sea, most likely as a result of carbon recycling between AOM and methanogenesis.

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