Temporal variability of the microbial food web (viruses to ciliates) under the influence of the Black Sea Water inflow (N. Aegean, E. Mediterranean)

Τhe entire pelagic microbial food web was studied during the winter-spring period in the frontal area of the North Aegean Sea. Abundance of viruses, heterotrophic bacteria, cyanobacteria, auto- and hetero-trophic flagellates, and ciliates, as well as bacterial production, were measured at three stations (MD1, MD2, MD3) situated along a N-S transect between the area directly influenced by the inflowing Black Sea water and the area covered by the Levantine water. Samples were collected in December 2009, and January, March, April, and May 2011. Station MD1 exhibited the highest values of abundance and integrated biomass of all microbial groups and bacterial production during all months, and MD3 the lowest. Bacteria dominated the total integrated biomass at all stations and months, followed by cyanobacteria, auto-, hetero-trophic flagellates and ciliates. On a temporal scale, the microbial food web was less important in March as all microbial parameters at all stations showed the lowest values. After the phytoplankton bloom in March, the heterotrophic part of the microbial food web (mainly) strongly increased, though the intensity of the phenomenon was diminished from North to South. Pico-sized plankton was found to be heterotrophic whereas nanoplankton was autotrophic. It seems that the influence of the Black Sea water on station MD1, permanent throughout the study period of early winter to late spring, was reflected in all microbial populations studied, and produced a more productive pelagic food web system, with potential consequences for the upper trophic levels.

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Heterotrophic bacterial growth and substrate utilization in the oligotrophic Eastern Mediterranean (Aegean Sea)

Mediterranean Marine Science ◽

10.12681/mms.238 ◽

2003 ◽

Vol 4 (1) ◽

pp. 23 ◽

Cited By ~ 8

Author(s):

U. CHRISTAKI ◽

F.V. WAMBEKE ◽

M. BIANCHI

Keyword(s):

Amino Acids ◽

Black Sea ◽

Bacterial Growth ◽

Bacterial Production ◽

Sea Water ◽

Eastern Mediterranean ◽

Aegean Sea ◽

Substrate Utilization ◽

The Black Sea ◽

Respiration Rates

Heterotrophic bacterial growth and substrate utilization were studied in March and September of 1997 in the oligotrophic Aegean Sea. Maximum velocities of ectoproteolytic activity (ectoaminopeptidase ctivity, EAP), as well as amino acid assimilation and respiration rates (AA-A, AA-R) were measured along with bacterial production (protein synthesis). At the northern stations which are influenced by the input of the Black Sea waters, rates at 5 m depth of EAP, AA-A and bacterial production were 2 to 3 times higher than at southern stations. Influenced by the Black Sea water, mean bacterial numbers in the 0-100 m layer showed typical oceanic concentrations averaging 0.7 x 10 6 cells ml -1 . These values, along with low bacterial production rates (30 ng C l -1 h -1 ) implied slow growth for bacteria and/or that a large number among them were inactive. Neither bacterial abundance nor production were correlated with primary production. The percentage of amino acids respired was higher in September compared to March, particularly in the northern Aegean (mean 69 %). The enzyme kinetic analysis showed a biphasic model, the transition between the high and low affinity enzymes being obtained at 50 ΜM. Ectoaminopeptidase activity was weakly correlated with bacterial production (p < 0.05), but strongly correlated with respiration rates of amino acids (p < 0.001), suggesting that the substrate used was devoted to maintain energy requirements.

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An Inverse Model Analysis of Planktonic Food Webs in Experimental Lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f94-206 ◽

1994 ◽

Vol 51 (9) ◽

pp. 2034-2044 ◽

Cited By ~ 45

Author(s):

Alain F. Vézina ◽

Michael L. Pace

Keyword(s):

Food Web ◽

Heterotrophic Bacteria ◽

Grazing Pressure ◽

Inverse Methods ◽

Trophic Levels ◽

Microbial Food Web ◽

Food Web Structure ◽

Planktonic Food ◽

Size Groups ◽

The Impact

We used inverse methods to reconstruct carbon flows in experimental lakes where the fish community had been purposely altered. These analyses were applied to three years of data from a reference lake and two experimental lakes located in Gogebic County, Michigan. We reconstructed seasonally averaged flows among two size groups of phytoplankton, heterotrophic bacteria, microzooplankton, cladocerans, and copepods. The inverse analysis produced significantly different flow networks for the different lakes that agreed qualitatively with known chemical and biological differences between lakes and with other analyses of the impact of fish manipulations on food web structure and dynamics. The results pointed to alterations in grazing pressure on the phytoplankton that parallel changes in the size and abundance of cladocerans and copepods among lakes. Estimated flows through the microbial food web indicated low bacterial production efficiencies and small carbon transfers from the microbial food web to the larger zooplankton. This study demonstrates the use of inverse methods to identify and compare flow patterns across ecosystems and suggests that microbial flows are relatively insensitive to changes at the upper trophic levels.

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Microbial food web dynamics during spring phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean)

Biogeosciences ◽

10.5194/bg-11-6739-2014 ◽

2014 ◽

Vol 11 (23) ◽

pp. 6739-6753 ◽

Cited By ~ 41

Author(s):

U. Christaki ◽

D. Lefèvre ◽

C. Georges ◽

J. Colombet ◽

P. Catala ◽

...

Keyword(s):

Southern Ocean ◽

Food Web ◽

Bacterial Production ◽

Trophic Levels ◽

Microbial Food Web ◽

Heterotrophic Nanoflagellates ◽

Viral Production ◽

Phytoplankton Blooms ◽

Food Web Dynamics ◽

Heterotrophic Production

Abstract. Microbial food web dynamics were determined during the onset of several spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island in the Southern Ocean (KEOPS2). The abundances of heterotrophic bacteria and heterotrophic nanoflagellates, bacterial heterotrophic production, bacterial respiration, and bacterial growth efficiency, were consistently higher in surface waters of the iron-fertilized sites than at the reference site in HNLC (high nutrient low chlorophyll) waters. The abundance of virus-like particles remained unchanged, but viral production increased by a factor of 6 in iron-fertilized waters. Bacterial heterotrophic production was significantly related to heterotrophic nanoflagellate abundance and viral production across all sites, with bacterial production explaining about 70 and 85%, respectively, of the variance of each in the mixed layer (ML). Estimated rates of grazing and viral lysis, however, indicated that heterotrophic nanoflagellates accounted for a substantially higher loss of bacterial production (50%) than viruses (11%). Combining these results with rates of primary production and export determined for the study area, a budget for the flow of carbon through the microbial food web and higher trophic levels during the early (KEOPS2) and the late phase (KEOPS1) of the Kerguelen bloom is provided.

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The chemical-microbiological characteristics of sea water and bottom sediments of the Kerch Strait and adjacent water areas

Marine Biological Journal ◽

10.21072/mbj.2017.02.3.07 ◽

2017 ◽

Vol 2 (3) ◽

pp. 75-85

Author(s):

E. A. Tikhonova ◽

N. V. Burdiyan ◽

O. V. Soloveva

Keyword(s):

Surface Layer ◽

Black Sea ◽

Bottom Sediments ◽

Heterotrophic Bacteria ◽

Sea Water ◽

Water Area ◽

The Black Sea ◽

Azov Sea ◽

Sea Bottom ◽

Oil Hydrocarbons

This paper presents the results of contamination level of sea bottom sediments and seawater in the water areas by the strait of the Black Sea and the Azov Sea by oil hydrocarbons and chloroform-extractable substances studies (spring, autumn 2016). Comparison of marine environment pollution levels with the results of previous studies (2007–2010) and sanitary norms is given. The quantitative characteristics of heterotrophic and oil-oxidizing microbiota in the designated areas are presented. It was determined that the concentration of oil hydrocarbons in the water surface layer in the water area by the strait of the Azov Sea did not exceed the current norm (0.05 mg·l-1). The single cases of the maximum permissible concentration exceeding were registered in the water area by the strait of the Black Sea (autumn 2016). In the surface layer of Azov Sea water, the number of heterotrophic bacteria ranged from 104 to 105 cells·ml-1, and the oil-oxidizing bacteria were isolated in single quantities. In the water area of the Black Sea region of the strait the number of heterotrophic bacteria was 106, the number of oil-oxidizing bacteria did not exceed 10 cells·ml-1. In comparison with the previous years’ data, there was an increase in quantitative indicators of chloroform-extractable substances and oil hydrocarbons in the sea bottom sediments. The overall level of pollution did not exceed the average values determined for the region. The number of heterotrophic bacteria in the sea bottom sediments varied in the Strait of Azov water area from 2,5·104 to 4,5·104 cells·g-1, while that of oil-oxidizing bacteria varied from 2,5·10 to 4,5·102 cells·g-1. In the sea bottom sediments of the Black Sea, the number of heterotrophic bacteria was 4,5·103 cells·g-1, the number of oil oxidizing bacteria was 10 cells·g-1.

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HYDROGEN FROM HYDROGEN SULPHIDE IN BLACK SEA

Alternative Energy and Ecology (ISJAEE) ◽

10.15518/isjaee.2019.01-03.049-055 ◽

2019 ◽

pp. 49-55

Author(s):

S. Z. Baykara ◽

E. H. Figen ◽

A. Kale ◽

T. N. Veziroglu

Keyword(s):

Hydrogen Production ◽

Black Sea ◽

Hydrogen Sulphide ◽

Sea Water ◽

Economic Value ◽

Environmental Pollutant ◽

The Black Sea ◽

Fuel Processing ◽

Acid Gas ◽

Reducing Bacteria

Hydrogen sulphide, an acid gas, is generally considered an environmental pollutant. As an industrial byproduct, it is produced mostly during fuel processing. Hydrogen sulphide occurs naturally in many gas wells and also in gas hydrates and gas-saturated sediments especially at the bottom of the Black Sea where 90% of the sea water is anaerobic.The anoxic conditions exist in the deepest parts of the basin since nearly 7300 years, caused by the density stratification following the significant influx of the Mediterranean water through the Bosphorous nearly 9000 years ago. Here, H2S is believed to be produced by sulphur reducing bacteria at an approximate rate of 10 000 tons per day, and it poses a serious threat since it keeps reducing the life in the Black Sea. An oxygen–hydrogen sulphide interface is established at 150–200 m below the surface after which H2S concentration starts increasing regularly until 1000 m, and finally reaches a nearly constant value of 9.5 mg/l around 1500 m depth.Hydrogen sulphide potentially has economic value if both sulphur and hydrogen can be recovered. Several methods are studied for H2S decomposition, including thermal, thermochemical, electrochemical, photochemical and plasmochemical methods.In the present work, H2S potential in the Black Sea is investigated as a source of hydrogen, an evaluation of the developing prominent techniques for hydrogen production from H2S is made, and an engineering assessment is carried out regarding hydrogen production from H2S in the Black Sea using a process design based on the catalytic solar thermolysis approach. Possibility of a modular plant is considered for production at larger scale.

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DISTRIBUTION OF DISSOLVED METHANE IN SURFACE COASTAL WATERS OF THE NORTHEASTERN PART OF THE BLACK SEA

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b93b237aa68.28587089 ◽

2017 ◽

Author(s):

Elena Kovaleva ◽

Alexander Izhitskiy ◽

Alexander Egorov ◽

...

Keyword(s):

Black Sea ◽

Natural Waters ◽

Sea Water ◽

The Black Sea ◽

Methane Formation ◽

Anthropogenic Pressure ◽

Russian Science ◽

Southeastern Part ◽

Dissolved Methane ◽

Continental Runoff

Studying of methane formation and distribution in natural waters is important for understanding of biogeochemical processes of carbon cycle, searching for oil and gas sections and evaluation of CH4 emissions for investigations of greenhouse effect. The Black Sea is the largest methane water body on our planet. However, relatively low values of methane concentration (closed to equilibrium with the atmospheric air) are typical of the upper aerobic layer. At the same time, the distribution pattern of CH4 in surface waters of coastal areas is complicated by the influence of coastal biological productivity, continental runoff, bottom sources, hydrodynamic processes and anthropogenic effect. The investigation is focused on the spatial variability of dissolved methane in the surface layer of the sea in coastal regions affected by the continental runoff and anthropogenic pressure. Unique in situ data on methane concentrations were collected along the ship track on 2 sections between Sochi and Gelendzhik (2013, 2014) and 2 sections between Gelendzhik and Feodosia (2015). Overall 170 samples were obtained. Gas-chromatographic analysis of the samples revealed increase of CH4 saturation in the southeastern part of the Crimean shelf and the Kerch Strait area. Such a pattern was apparently caused by the influence of the Azov Sea water spread westward along the Crimean shore from the strait. This work was supported by the Russian Science Foundation, Project 14-50-00095 and the Russian Foundation for Basic Research, Project 16-35-00156 mol_a.

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LUMINESCENCE OF THE BLACK SEA MICROSCOPIC FUNGI CULTURES

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b946ac0fc74.55415483 ◽

2017 ◽

Author(s):

Olga Mashukova ◽

Yuriy Tokarev ◽

Nadejda Kopytina ◽

...

Keyword(s):

Fresh Water ◽

Black Sea ◽

Ethyl Alcohol ◽

Light Emission ◽

Sea Water ◽

Control Culture ◽

Chemical Stimulation ◽

The Black Sea ◽

The Given ◽

First Time

We studied for the first time luminescence characteristics of the some micromycetes, isolated from the bottom sediments of the Black sea from the 27 m depth. Luminescence parameters were registered at laboratory complex “Svet” using mechanical and chemical stimulations. Fungi cultures of genera Acremonium, Aspergillus, Penicillium were isolated on ChDA medium which served as control. Culture of Penicillium commune gave no light emission with any kind of stimulation. Culture of Acremonium sp. has shown luminescence in the blue – green field of spectrum. Using chemical stimulation by fresh water we registered signals with luminescence energy (to 3.24 ± 0.11)•108 quantum•cm2 and duration up to 4.42 s, which 3 times exceeded analogous magnitudes in a group, stimulated by sea water (p < 0.05). Under chemical stimulation by ethyl alcohol fungi culture luminescence was not observed. Culture of Aspergillus fumigatus possessed the most expressed properties of luminescence. Stimulation by fresh water culture emission with energy of (3.35 ± 0.11)•108 quantum•cm2 and duration up to 4.96 s. Action of ethyl alcohol to culture also stimulated signals, but intensity of light emission was 3–4 times lower than under mechanical stimulation. For sure the given studies will permit not only to evaluate contribution of marine fungi into general bioluminescence of the sea, but as well to determine places of accumulation of opportunistic species in the sea.

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SITE-SPECIFIC EQUATIONS OF STATE FOR COASTAL SEA AREAS AND INLAND WATER BODIES

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b9452bebe47.34318019 ◽

2017 ◽

Author(s):

Natalia Andrulionis ◽

Ivan Zavialov ◽

Elena Kovaleva ◽

...

Keyword(s):

Equation Of State ◽

Black Sea ◽

Water Samples ◽

Equations Of State ◽

Sea Water ◽

Ionic Composition ◽

Water Bodies ◽

Aral Sea ◽

The Black Sea ◽

Coastal Sea

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water samples from the Aral Sea, the Black Sea and the Issyk-Kul Lake were performed using a high-precision laboratory density meter. The obtained results were compared with the density values calculated for the considered water samples by the EOS-80 equation. It was shown that difference in ionic composition between Standard Seawater and the considered water bodies results in significant inaccuracies in determination of water density using the EOS-80 equation. Basing on the laboratory measurements of density under various salinity and temperature values we constructed a new equation of state for the Aral Sea and the Black Sea water samples and estimated errors for their coefficients.

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CORRELATION OF THE BLACK, MARMARA AND AEGEAN SEAS DURING THE HOLOCENE

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.21610/conferencearticle_58b4315c686d6 ◽

2017 ◽

Author(s):

Nikolay Esin ◽

Vladimir Ocherednik ◽

Vladimir Ocherednik

Keyword(s):

Mathematical Model ◽

Sea Level ◽

Black Sea ◽

Aegean Sea ◽

The Black Sea ◽

Sea Level Changes ◽

The Holocene

A mathematical model describing the change in the Black Sea level depending on the Aegean Sea level changes is presented in the article. Calculations have shown that the level of the Black Sea has been repeating the course of the Aegean Sea level for the last at least 6,000 years. And the level of the Black Sea above the Aegean Sea level in the tens of centimeters for this period of time.

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