Eutrophication and annual primary production of phytoplankton in the deep-water part of the Black Sea

Oceanology ◽  
2011 ◽  
Vol 51 (4) ◽  
pp. 616-625 ◽  
Author(s):  
O. A. Yunev
Keyword(s):  
Primary Production ◽  
Black Sea ◽  
Deep Water ◽  
The Black Sea ◽  
Annual Primary Production ◽  
Deep Water Part

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 Seasonal dynamics of the main primary production characteristics of phytoplankton and its microzooplankton grazing in the surface coastal waters of the Black sea

2017 ◽  
pp. 114-120
Author(s):  
L.V. Stelmakh ◽  
Keyword(s):  
Primary Production ◽  
Black Sea ◽  
Coastal Waters ◽  
Grazing Rate ◽  
The Black Sea ◽  
Average Cell ◽  
Average Cell Volume ◽  
Annual Primary Production ◽  
Microzooplankton Grazing ◽  
Production Characteristics

Seasonal variability of phytoplankton biomass, “pure” primary production and its share consumed micro¬zooplankton, as well as the specific microzooplankton grazing rate of phytoplankton for the surface layer (0-1 m) in coastal waters of the Black Sea was studied. Almost 80% of the total annual primary’ produc¬tion of phytoplankton is created by phytoplankton with the average cell volume .from 150 to 4000 mm3. The main share of annual primary production, eaten by microzooplankton (86%) is also associated with these algae sized groups.

scholarly journals Modeling the nitrogen fluxes in the Black Sea using a 3D coupled hydrodynamical-biogeochemical model: transport versus biogeochemical processes, exchanges across the shelf break and comparison of the shelf and deep sea ecodynamics

2004 ◽  
Vol 1 (1) ◽  
pp. 107-166 ◽  
Author(s):  
M. Grégoire ◽  
J. M. Beckers
Keyword(s):  
Primary Production ◽  
Water Column ◽  
Black Sea ◽  
Deep Sea ◽  
Shelf Break ◽  
The Black Sea ◽  
Biogeochemical Model ◽  
Euphotic Layer ◽  
Open Sea ◽  
Annual Primary Production

Abstract. A 6-compartment biogeochemical model of nitrogen cycling and plankton productivity has been coupled with a 3D general circulation model in an enclosed environment (the Black Sea) so as to quantify and compare, on a seasonal and annual scale, the typical internal biogeochemical functioning of the shelf and of the deep sea as well as to estimate the nitrogen and water exchanges at the shelf break. Model results indicate that the annual nitrogen net export to the deep sea roughly corresponds to the annual load of nitrogen discharged by the rivers on the shelf. The model estimated vertically integrated gross annual primary production is 130 g C m-2yr-1 for the whole basin, 220 g C m-2yr-1 for the shelf and 40 g C m-2yr-1 for the central basin. In agreement with sediment trap observations, model results indicate a rapid and efficient recycling of particulate organic matter in the sub-oxic portion of the water column (60-80m) of the open sea. More than 95% of the PON produced in the euphotic layer is recycled in the upper 100m of the water column, 87% in the upper 80 m and 67% in the euphotic layer. The model estimates the annual export of POC towards the anoxic layer to 4 1010mol yr-1. This POC is definitely lost for the system and represents 2% of the annual primary production of the open sea.

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.

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.

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