Noble gas anomalies related to high-intensity methane gas seeps in the Black Sea

2008 ◽  
Vol 265 (3-4) ◽  
pp. 396-409 ◽  
Author(s):  
C.P. Holzner ◽  
D.F. McGinnis ◽  
C.J. Schubert ◽  
R. Kipfer ◽  
D.M. Imboden
Keyword(s):  
Black Sea ◽  
High Intensity ◽  
Noble Gas ◽  
The Black Sea ◽  
Methane Gas ◽  
Gas Seeps

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.

Methane gas emissions of the Black Sea—mapping from the Crimean continental margin to the Kerch Peninsula slope

2019 ◽  
Vol 40 (4) ◽  
pp. 467-480 ◽  
Author(s):  
Miriam Römer ◽  
Heiko Sahling ◽  
Christian dos Santos Ferreira ◽  
Gerhard Bohrmann
Keyword(s):  
Black Sea ◽  
Continental Margin ◽  
The Black Sea ◽  
Gas Emissions ◽  
Methane Gas ◽  
Kerch Peninsula

Natural oil and gas seeps on the Black Sea floor

2004 ◽  
Vol 24 (3) ◽  
Author(s):  
R.P. Kruglyakova ◽  
Y.A. Byakov ◽  
M.V. Kruglyakova ◽  
L.A. Chalenko ◽  
N.T. Shevtsova
Keyword(s):  
Black Sea ◽  
Oil And Gas ◽  
The Black Sea ◽  
Sea Floor ◽  
Natural Oil ◽  
Gas Seeps

scholarly journals Methanotrophic microbial communities associated with bubble plumes above gas seeps in the Black Sea

2006 ◽  
Vol 7 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Carsten J. Schubert ◽  
Edith Durisch-Kaiser ◽  
Christian P. Holzner ◽  
Lucia Klauser ◽  
Bernhard Wehrli ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Black Sea ◽  
The Black Sea ◽  
Bubble Plumes ◽  
Gas Seeps

scholarly journals Tsunami hazard in the Black Sea and the Azov Sea: a new tsunami catalogue

2011 ◽  
Vol 11 (3) ◽  
pp. 945-963 ◽  
Author(s):  
G. A. Papadopoulos ◽  
G. Diakogianni ◽  
A. Fokaefs ◽  
B. Ranguelov
Keyword(s):  
Black Sea ◽  
High Intensity ◽  
Tsunami Hazard ◽  
Moderate Intensity ◽  
The Black Sea ◽  
Standard Format ◽  
Azov Sea ◽  
Grade Scale ◽  
Statistical Sample ◽  
Messina Strait

Abstract. Data on tsunamis occurring in the Black Sea and the Azov Sea from antiquity up to the present were updated, critically evaluated and compiled in the standard format developed since the 90's for the New European Tsunami Catalogue. Twenty nine events were examined but three of them, supposedly occurring in 557 AD, 815 AD and 1341 or 1343, were very likely falsely reported. Most of the remaining 26 events were generated in Crimea, offshore Bulgaria as well as offshore North Anatolia. For each of the 26 events examined, 22 events were classified as reliable ones receiving a score of 3 or 4 on a 4-grade reliability scale. Most of them were caused by earthquakes, such as the key event 544/545 of offshore Varna, but a few others were attributed either to aseismic earth slumps or to unknown causes. The tsunami intensity was estimated using the traditional 6-grade scale and the new 12-grade scale introduced by Papadopoulos and Imamura (2001). From 544/545 up to now, only two reliable events of high intensity K ≥ 7 have been reported, which very roughly indicates that the mean repeat time is ∼ 750 years. Five reliable tsunamis of moderate intensity 4 ≤ K < 7 have been observed from 1650 up to the present, which implies a recurrence of 72 years on the average. Although these calculations were based on a very small statistical sample of tsunami events, the repeat times found are consistent with the theoretical expectations from size-frequency relations. However, in the Black Sea there is no evidence of tsunamis of very high intensity (K ∼ 10) such as the AD 365, 1303 and 1956 ones associated with large earthquakes occurring along the Hellenic arc and trench, Greece, or the 1908 one in Messina strait, Italy. This observation, along with the relatively low tsunami frequency, indicates that the tsunami hazard in the Black Sea is low to moderate but not negligible. The tsunami hazard in the Azov Sea is very low because of the very low seismicity but also because of the shallow water prevailing there. In fact, only three possible tsunami events have been reported in the Azov Sea.

scholarly journals The Influence of Parasitic Infection on the Black Sea Whiting, Merlangius merlangus euxinus (Gadidae), Morphophysiological and Biochemical Parameters

2013 ◽  
Vol 47 (4) ◽  
pp. 309-317 ◽  
Author(s):  
E. N. Skuratovskaya ◽  
V. M. Yurakhno ◽  
A. V. Zavyalov
Keyword(s):  
Black Sea ◽  
High Intensity ◽  
Biochemical Parameters ◽  
Parasitic Infection ◽  
The Black Sea ◽  
Hepatosomatic Index ◽  
Antioxidant Enzyme Activities ◽  
Average Intensity ◽  
Intensity Of Infection ◽  
Merlangius Merlangus

Abstract Complex influence of infection by myxosporeans Myxidium gadi Georgevitsch, 1916; Ceratomyxa merlangi Zaika, 1966 and nematode Hysterothylacium aduncum (Rudolphi, 1802) on the morphophysiological and biochemical parameters of the Black sea whiting Merlangius merlangus euxinus (Nordmann, 1840) were studied. Significant decrease of spleenosomatic index and increase of hepatosomatic index in fish with average and high intensity of infection were found. The dependence of hepatic antioxidant enzyme activities on intensity of infection was observed. Increase of superoxidismutase, catalase, glutation-S-transferase activities in fish with average and high intensity of infection and decrease of peroxidase activity in specimens with average intensity of infection were shown.

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