scholarly journals DEVELOPMENT OF AN EMPIRICAL MODEL OF pH LONG-TERM CHANGES IN THE SURFACE WATERS OF THE DEEP-WATER PART OF THE BLACK SEA

2021 ◽  
pp. 22-30
Author(s):  
E.A. Grebneva ◽  
Keyword(s):  
Black Sea ◽  
Deep Water ◽  
Ph Value ◽  
Average Rate ◽  
Field Studies ◽  
The Black Sea ◽  
Climate Trend ◽  
Using Data ◽  
Deep Water Part

The paper analyzes the interannual variability of the pH value in the surface layer of the deep-water part of the Black Sea for the period from 1957 to 1996. For the period from 1977 to 1996, an empirical mod-el of the time series is developed and a retrospective forecast is calculated with an assessment of its quali-ty using data from field studies performed from 2019 to 2021. In the interannual course of pH, two sig-nificant quasi-cyclic components of variability with periods of about 6, 7 years and 2.5 years are distin-guished. The highlighted trend (climate trend) indicates a decrease in the pH value for the period from 1977 to 2021. with an average rate of about 0.01 pH units/10 years. The data of field studies in 2019-2021 confirm the calculations obtained.

scholarly journals Changes in the Oxygen Regime in the Deep Part of the Black Sea in 1980–2019

2021 ◽  
Vol 37 (2) ◽  
Author(s):  
A. V. Vidnichuk ◽  
S. K. Konovalov ◽  
◽  
Keyword(s):  
Oxygen Saturation ◽  
Black Sea ◽  
Deep Water ◽  
Anthropogenic Factors ◽  
The Black Sea ◽  
Expert Assessment ◽  
Distance Method ◽  
Oxygen Regime ◽  
Aerobic Zone ◽  
Deep Water Part

Purpose. Assessing changes in the oxygen regime of the deep-water part of the Black Sea under the influence of climatic and anthropogenic factors over the past 40 years is the goal of the work. Methods and Results. For the analysis, the expedition data (2015–2019) and those from the Databank of the Marine Hydrophysical Institute, Russian Academy of Sciences, (1980–2013) were used. The data for the deep-water part of the Black Sea (the depths exceeding 200 m) were selected from the array. The data on hydrophysical and hydrochemical parameters were subjected to expert assessment, and those including random errors in the values were excluded from the array. Then the average profiles of temperature, salinity, oxygen concentration, oxygen saturation, and nitrates concentration were plotted in the density scale (σt). Averaging was carried out by the inverse distance method followed by additional smoothing by the low-frequency filtering method. Conclusions. Against the background of the tendency of temperature increase in the upper layers of the water column and decrease of winter convective mixing intensity, the oxygen supply diminishes in all the layers of the Black Sea aerobic zone. Having been analyzed, the data for the 1980–2019 period showed that at the present stage, a “regime shift” resulting from the joint effect of climate changes and anthropogenic load took place in the ecosystem of the deep-water part of the Black Sea. Decrease in the oxygen saturation of water throughout the entire thickness of the aerobic zone shows that the process of the Black Sea basin eutrophication constitutes a significant factor affecting oxygen dynamics in the Black Sea waters.

scholarly journals CLIMATIC DISTRIBUTION Of pH IN THE DEEP-WATER PART OF THE BLACK SEA

2017 ◽  
Vol 4 ◽  
pp. 88-95
Author(s):  
A.B. Polonsky ◽  
◽  
E.A. Grebneva ◽  
Keyword(s):  
Black Sea ◽  
Deep Water ◽  
The Black Sea ◽  
Deep Water Part

scholarly journals Changes in the Oxygen Regime in the Deep Part of the Black Sea in 1980–2019

2021 ◽  
Vol 28 (2) ◽  
Author(s):  
A. V. Vidnichuk ◽  
S. K. Konovalov ◽  
◽  
Keyword(s):  
Oxygen Saturation ◽  
Black Sea ◽  
Deep Water ◽  
Anthropogenic Factors ◽  
The Black Sea ◽  
Expert Assessment ◽  
Distance Method ◽  
Oxygen Regime ◽  
Aerobic Zone ◽  
Deep Water Part

Purpose. Assessing changes in the oxygen regime of the deep-water part of the Black Sea under the influence of climatic and anthropogenic factors over the past 40 years is the goal of the work. Methods and Results. For the analysis, the expedition data (2015–2019) and those from the Databank of the Marine Hydrophysical Institute, Russian Academy of Sciences, (1980–2013) were used. The data for the deep-water part of the Black Sea (the depths exceeding 200 m) were selected from the array. The data on hydrophysical and hydrochemical parameters were subjected to expert assessment, and those including random errors in the values were excluded from the array. Then the average profiles of temperature, salinity, oxygen concentration, oxygen saturation, and nitrates concentration were plotted in the density scale (σt). Averaging was carried out by the inverse distance method followed by additional smoothing by the low-frequency filtering method. Conclusions. Against the background of the tendency of temperature increase in the upper layers of the water column and decrease of winter convective mixing intensity, the oxygen supply diminishes in all the layers of the Black Sea aerobic zone. Having been analyzed, of the data for the 1980–2019 period showed that at the present stage, a "regime shift" resulting from the joint effect of climate changes and anthropogenic load took place in the ecosystem of the deep-water part of the Black Sea. Decrease in the oxygen saturation of water throughout the entire thickness of the aerobic zone shows that the process of the Black Sea basin eutrophication constitutes a significant factor affecting oxygen dynamics in the Black Sea waters.

scholarly journals Space-time ph variability in the Black Sea

2019 ◽  
Vol 486 (4) ◽  
pp. 494-499
Author(s):  
A. B. Polonsky ◽  
E. A. Grebneva
Keyword(s):  
Black Sea ◽  
Ph Value ◽  
Space Time ◽  
The Black Sea ◽  
Surface Ph ◽  
Absolute Value ◽  
Intermediate Layers ◽  
Acidic Waters ◽  
Upward Moving

Based on the archival data for the period from 1956 to 2010, space-time pH changes in the Black Sea upper layer are analyzed. In the surface layer, a statistically significant decreasing in the pH value (at a level of -0.06 pH units per 50 years) was found. It is mostly due to the growing concentrations of carbon dioxide in the atmosphere. Intermediate layers are characterized by a negative pH trend which absolute value more than fivefold exceeds the surface pH trend. Likely reason of the pH decreases here is a long-term upward moving of acidic waters with a typical velocity of ~1 m per year.

scholarly journals Mud-volcanic deposits of methane gas hydrates in the Black Sea

2021 ◽  
Vol 230 ◽  
pp. 01005
Author(s):  
Yevgeny Shnyukov ◽  
Volodymyr Kobolev ◽  
Valentina Yanko
Keyword(s):  
Black Sea ◽  
Deep Water ◽  
Gas Hydrates ◽  
Mineral Deposits ◽  
The Black Sea ◽  
Mud Volcanoes ◽  
Methane Gas ◽  
Volcanic Deposits ◽  
Methane Gas Hydrates ◽  
Deep Water Part

This paper discusses the formation of a special mud-volcanic type of gas hydrate accumulation in the deep-water part of the Black Sea. The main conclusions are based on the results of geological and geophysical studies of mud volcanoes carried out in the course of numerous scientific cruises between 1970-2015. Comparison of the Black Sea submarine mud volcanoes with their on-land analogues indicates the possible use of compensatory depressions, called “recessed synclines”, accompanying mud volcanoes, which is revealed in the course of prospecting and exploration of mineral deposits. In the sea they are represented by ring deposits of methane gas hydrates.

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