scholarly journals Emiliania huxleyi blooms in the Black Sea: influence of abiotic and biotic factors

Botanica ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 172-184 ◽  
Author(s):  
Liudmila Stelmakh ◽  
Tatiana Gorbunova
Keyword(s):  
Black Sea ◽  
Emiliania Huxleyi ◽  
Uneven Distribution ◽  
The Black Sea ◽  
Total Biomass ◽  
Biotic Factors ◽  
Nitrogen And Phosphorus ◽  
Seasonal Adaptation ◽  
Solar Radiation Intensity ◽  
Abiotic And Biotic Factors

Abstract Stelmakh L.V., Gorbunova T.I., 2018: Emiliania huxleyi blooms in the Black Sea: influence of abiotic and biotic factors. - Botanica, 24(2): 172-184. The studies were conducted in the Black Sea in deep and shallow water areas in October 2010 and May 2013. The main abiotic and biotic factors, which control spring and autumn coccolithophorid Emiliania huxleyi blooms, were identified. During late May this phenomenon was observed under optimal light and temperature conditions, and also optimal ratio between mineral forms of nitrogen and phosphorus (N/P) in the water. Biotic variables (the net growth rate of phytoplankton and relative dinoflagellates share in its total biomass) determined the uneven distribution of E. huxleyi within a bloom. In October, water temperature was almost 4ºС lower compared to that in May, and solar radiation intensity decreased approximately by 2-3 times. However, as a result of seasonal adaptation to light and temperature, E. huxleyi abundance reached blooming level. In that period, the variability of N/P ratio in the water and the relative share of diatoms in total biomass of phytoplankton played a major role in the uneven distribution of this coccolithophorid within the studied area. In the areas with low water salinity, a bloom was not developing. Within the main part of the studied water area, the major source of nitrogen was ammonium, which was favourable for the growth of E. huxleyi and dinoflagellates, but limited the growth of diatoms.

Effect of Certain Abiotic and Biotic Factors on Spawning of the European Sprat Sprattus sprattus (Linnaeus, 1758) in the Black Sea in November 2016–2017

Oceanology ◽  
2021 ◽  
Vol 61 (1) ◽  
pp. 58-68
Author(s):  
T. N. Klimova ◽  
I. V. Vdodovich ◽  
B. E. Anninsky ◽  
A. A. Subbotin ◽  
P. S. Podrezova ◽  
...  
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Biotic Factors ◽  
Sprattus Sprattus ◽  
Abiotic And Biotic Factors

7000 Years of Emiliania huxleyi Viruses in the Black Sea

Science ◽  
2011 ◽  
Vol 333 (6041) ◽  
pp. 451-452 ◽  
Author(s):  
M. J. L. Coolen
Keyword(s):  
Black Sea ◽  
Emiliania Huxleyi ◽  
The Black Sea

scholarly journals Winter jellyfish macroplankton off the coastal of Crimea

2016 ◽  
Vol 1 (4) ◽  
pp. 22-29
Author(s):  
S. M. Ignatyev ◽  
V. V. Gubanov ◽  
N. A. Datsyk
Keyword(s):  
Black Sea ◽  
Size Range ◽  
Size Structure ◽  
The Black Sea ◽  
Winter Period ◽  
Small Range ◽  
Total Biomass ◽  
Southern Coast ◽  
South Eastern ◽  
Azov Sea

Predatory macroplankton of jellyfish species is an important component of the pelagic ecosystem. It is capable of mass development, and may influence pelagic communities. Surveillance monitoring of jellyfish populations can detect the seasonal and long-term trends of their variability and assess the role of jellyfish in the trophic structure of the pelagic zone. Monitoring of plankton community (jellyfish macroplankton) off the coastal of Crimea from the Cape Tarkhankut to the Kerch coast (including the Azov Sea) in winter period is presented. 22 comprehensive oceanographic stations from Cape Tarkhankut to the Kerch Strait and in Azov Sea at the depths of up to 100 m were made. We used a Bogorov — Russ plankton net (entrance area is 0.5 square meters) for collecting plankton in the upper 100-m water layer. Jellyfish were measured immediately, we used a standard method of measuring and calculated the mass of the individual instances by the formulas. The biomass is calculated as the product of the abundance and the average wet weight of organisms in the population. Abundance and biomass macroplankton were counted per square meter of water surface or per the volume of filtered water. The species composition of jellyfish macroplankton was represented by 1 species of jellyfish and 3 species of ctenophores. Aurelia aurita dominated in biomass (98 % of the total biomass of gelatinous macroplankton)  everywhere; Pleurobrachia and Aurelia dominated in abundance (67 and 25 % respectively). The share of both species of ctenophores-invaders did not exceed 8 %. The average relative abundance of jellyfish along the coast of Crimea was fluctuated between 9 and 43 %, comb jellies — from 32 to 77 %. Quantitative distribution of gelatinous macroplankton was non-uniform — from complete absence to 83.3 g·m-3 (average of 12.6 g·m-3). The highest biomass was registered in the area of Sevastopol and Eupatoria, the minimum — off the southern coast of Crimea. Jellyfish were noted at almost all stations. Their biomass reached a value of 18 g·m-3. Distribution of jellyfish is characterized by marked heterogeneity with higher values of abundance and biomass in the area of the southern coast of Crimea and lower — in the stations in the western part of the Black Sea. Aurelia was presented with large dome diameter of 21–220 mm (average diameter — 93 mm). The bulk of the population was accounted for last year’s individuals generation. Biomass of the ctenophore M. leidyi varied from 86 to 4788 mg·m-3 (average of 1595 mg·m-3). The structure of its population was represented by wide size range of animals — 10–65 mm, while the share of larger animals of 60–100 % was observed in the western and south-eastern parts of the Black Sea. On the southern coast of Crimea 45 % of population of ctenophore were animals of 15–25 mm. Biomass of the ctenophore B. ovata was within 34.8–1316.6 mg·m-3 (average of 371.4 mg·m-3). Its abundance varied within a small range, except the area of Feodosia stations, where the maximum value was observed (it was more than 1 g·m-3). B. ovata population consisted of individuals of 20–40 mm long, while it formed the basis of immature specimens of 20–30 mm (50–70 % of the total). In Kerch area their share has reached 100 %. There were hibernating animals of last year’s generation. The coldwater ctenophore Pleurobrachia pileus was present almost everywhere, with biomass from 0.1 to 6.0 mg·m-3. Maximum values of abundance were observed in Alushta region. The stations of Crimean southern coast were characterized by intermediate, relatively flat values. South-eastern and western parts of the Black Sea were marked by similar values of abundance and biomass. In all studied regions, the prevailing size group in the structure of P. pileus populations were individuals with a  diameter of 10 mm. In the deep-sea area of the southern part of Crimea population was represented in the larger size range, and the proportion of animals ranging in size from 11 to 20 mm was low (5 %). In general, “winter” composition, size structure and abundance of jellyfish off the coast of the Crimea are the same of indicators in the coastal waters of Sevastopol. But the results show the existence of certain differences in the structure and quantitative development of jellyfish macroplankton in southern and  western coasts of Crimea.

scholarly journals Variability of the food potential of the Kerch strait and the black sea pre-strait zone as a prospective area for the development of mollusks Mariculture

2021 ◽  
Vol 258 ◽  
pp. 04007
Author(s):  
Nataliy Sitnik
Keyword(s):  
Black Sea ◽  
Suspended Matter ◽  
Zooplankton Community ◽  
The Black Sea ◽  
Dynamic Factor ◽  
Total Biomass ◽  
Algal Flora ◽  
High Productivity ◽  
Larval Stages ◽  
Kerch Strait

Based on the data of integrated observations, the variability of phytoplankton, the amount of suspended organic matter and zooplankton of the pelagic zone of the Kerch Strait and the pre-strait zone of the Black Sea is considered. The algal flora of the entire Black Sea, the Kerch Strait and the pre-strait is characterized by the predominance of diatoms over pyridineas (pyrrophytes or dinoflagellates). The study of the species range, number and biomass of the phytoplankton community during several periods of the year showed that its dynamics is largely dependent on seasonal weather changes (climate). In the process of phytoplankton development, several phases of autogenic succession were revealed. It is expressed in a sequential change in phytoplankton forms, changes in its abundance and biomass typical of the eastern shelf of the Black Sea. The zooplankton community of the Kerch Strait is represented by micro-, meso- and macro- zooplankton typical of the Black Sea. Microzooplankton is represented by zooflagellates and protozoa, as well as by early larval stages of planktonic crustaceans, apendicularia and mollusks. Its total biomass averages about 80 mg/m3.The above analysis of the collected material allows us to conclude that the distribution of suspended matter and larvae is related primarily to the peculiarities of water circulation in the strait. In the case of low concentrations of larvae, the dynamic factor can be decisive in the process of sedimentation intensity. The amounts of suspended matter can reach 20 mg/m3, which is 2-3 times higher than on average for the Black Sea. It further demonstrates the high productivity of waters and the prospects of the latter to be the area for commercial growing of mussels.

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 Nutrients Dynamics in the Surface Waters of the Black Sea

2020 ◽  
Vol 37 (6) ◽  
Author(s):  
N. A. Orekhova
Keyword(s):  
Black Sea ◽  
Phytoplankton Bloom ◽  
Inorganic Nitrogen ◽  
Water Layer ◽  
The Black Sea ◽  
Deep Part ◽  
Nitrogen And Phosphorus ◽  
Current State ◽  
Nutrients Concentration ◽  
Dissolved Silicon

Purpose. One of the key characteristics of water quality and marine ecosystems’ sustainability is nutrients supply, which are the main factors of phytoplankton bloom. Since the mid 20th century, in the northwestern Black Sea and on its western shelf, significant changes in nutrients concentrations took place, which were manifested in increase of the inorganic nitrogen and phosphorus concentrations, and decrease of the dissolved silicon content, that in its turn, led to a strong anthropogenic eutrophication of the above-mentioned regions. The aim of the work is to assess the current state of the Black Sea based on the data on the nutrients distribution and dynamics in the surface water layer. Methods and Results. The data obtained in the cruises of R/V “Professor Vodyanitsky” in 2016–2019 were analyzed. The main regions under study included the deep part of the Black Sea, as well as the Crimean and Caucasian sectors of the economic zone of Russia. The data obtained showed significant variability in the nutrients concentration both in the coastal and open areas. Conclusions. A decrease of nutrients concentration in 2016–2019 as compared to that in 2009–2014 was noted, that can indicate a decrease in the eutrophication degree and an improvement of the Black Sea waters quality. Intra-annual variability of the nutrients concentration in the sea surface layer is observed. No pronounced features in spatial variability of the nutrients concentration in this layer were revealed. It is assumed that in the central deep part of the sea, their concentrations are conditioned mainly by the physical processes of water transfer. In addition to physical transport, the increased nutrients concentrations in the coastal areas are, probably, also related to influence of the anthropogenic factor, namely inflow of nutrients from the coastal sources or their formation resulting from the biogeochemical processes which include organic matter.

scholarly journals LONG-TERM CHANGES OF COPEPODA (CRUSTACEA) ABUNDANCE AND BIOMASS IN THE DANUBE AND ODESA REGIONS OF THE BLACK SEA AS INDICATOR OF WATER QUALITY

2021 ◽  
Author(s):  
Yuliia Kharytonova ◽  
◽  
Vasil Dyadichko ◽  
Keyword(s):  
Black Sea ◽  
Fish Larvae ◽  
Ecological Status ◽  
Zooplankton Biomass ◽  
The Black Sea ◽  
Total Biomass ◽  
Ecological State ◽  
Total Zooplankton ◽  
Main Components ◽  
Total Zooplankton Biomass

Copepoda are the most important zooplanktonic group constituting the primary food for fish larvae and some fishes. Copepoda have the longest life cycles among the Black Sea mesozooplankton, so their biomass and percentage of total zooplankton biomass is greatly reduced by eutrophication. The percentage of Copepoda from the total biomass of zooplankton is a reliable indicator of the ecological status of the water bodies. For the Black Sea marine waters the indicator of “good” ecological status (GES) is the average annual biomass of Copepoda, which exceeds 45% of the total biomass of zooplankton. Changes of total biomass of zooplankton, biomass of Copepoda, the abundance and biomass of dominant species – Oithona davisae Ferrari F. D. & Orsi, 1984, Acartia (Acartiura) clausi Giesbrecht, 1889 and A. (Acanthacartia) tonsa Dana, 1849 in the Danube and Odesa marine regions from 1970 to 2019 were analysed. Also the ecological quality class in the Nort-Western part of Black sea by Copepoda indicators from 2004 to 2017 were established according to Water Framework Directive US. The total zooplankton biomass had been decreasing in Ukrainian waters and % of Copepoda from total zooplankton biomass was increasing. These tendencies shown a positive change in the forage base of commercial planktophagous fishes and ecological class status of the investigated aquatories. The abundance and biomass of O. davisae, A. clausi and A. tonsa were decreased from 2016 to 2019. The highest values of their metrics were in 2016 and the lowest rates observed in 2019. O. davisae, A. clausi and A. tonsa were the main components of copepods number and biomass. The Acartia species formed higher part of Copepoda biomass than O. davisae. The ecological state was “good” (GES) only in Danube-Dnieper coastal waters and Danube delta in 2004–2017 where Copepoda formed more than 45 % of total zooplankton biomass. In waters of Northwester Black Sea bays, shallow and deepwater shelfs the ecological state was “Bad” (notGES), the part of Copepoda was lower than 45 %.

scholarly journals Intercomparison of five nets used for mesozooplankton sampling

2015 ◽  
Vol 16 (3) ◽  
pp. 550 ◽  
Author(s):  
D. ALTUKHOV ◽  
I. SIOKOU ◽  
M. PANTAZI ◽  
K. STEFANOVA ◽  
F. TIMOFTE ◽  
...  
Keyword(s):  
Black Sea ◽  
Size Structure ◽  
Mesh Size ◽  
Taxonomic Composition ◽  
The Black Sea ◽  
Total Biomass ◽  
Correction Factors ◽  
Fine Mesh ◽  
Large Animals ◽  
Ecosystem Changes

Intercomparison of nets commonly used for mesozooplankton sampling in the Black and Mediterranean seas was attempted within SESAME (Southern European Seas: Assessing and Modelling Ecosystem Changes) project. Five nets were compared: three Juday nets equipped with 150 μm, 180 μm and 200 μm mesh size, Nansen net (100 μm mesh size) and WP2 (200 μm mesh size). Replicated samples were collected at one station in the western Black Sea offshore waters in April 2009. Collected samples were analyzed at species level (except for meroplankton), stages (for copepods) and size length. A decrease of total abundance values was observed with increasing mesh size, due to the significantly higher numbers of animals smaller than 1 mm in the samples obtained by fine mesh size than with coarser nets. Few comparisons were revealed significant for the abundance of animals with 1-2 mm length, while no significance was detected for specimens larger than 2 mm. The above differences resulted in discripancies between nets regarding species and stages composition. Biomass values did not differ significantly between nets, due to the strong contribution to total biomass of the large animals fraction (Calanus euxinus). The smallest and the largest animals revealed high variability between replicates collected by Nansen, Juday- 200 μm and WP2 nets. Correction factors were calculated for the conversion of abundance values between each couple of nets. The detected differences between nets regarding the abundance and biomass, the community taxonomic composition and size structure, as well as the estimated correction factors, provide useful information for the harmonization of data obtained by the above nets in the Black Sea.

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