scholarly journals Structure of the macrozoobenthos assemblages in the central part of the northwestern Black Sea shelf (Zernov's Phyllophora field) at the beginning of the 21st century

2021 ◽  
Vol 39 ◽  
pp. 92-108
Author(s):  
Nikolai K. Revkov ◽  
Natalia A. Boltachova
Keyword(s):  
20Th Century ◽  
Black Sea ◽  
Red Algae ◽  
Water Area ◽  
Ecological Crisis ◽  
The Black Sea ◽  
Bottom Fauna ◽  
Soft Bottom ◽  
Northwestern Shelf ◽  
Soft Bottoms

In the first half of the 20th century, there was an extensive biocoenosis of the unattached red algae Phyllophora crispa on the mussel muds of the central section of the Black Sea’s northwestern shelf, which is known as Zernov’s Phyllophora Field (ZPF). At that time, the area of ZPF was approximately 11000 km2. More than a century after the description of ZPF, long-term changes in its phyto- and zoobenthos have been noted. A period of ecological crisis of the Black Sea ecosystem during the second half of the 20th century was destructive for the phytobenthos of ZPF, with the complete degradation of unattached Phyllophora biocoenosis. In contrast, after a sharp decline in the quantitative development of macrozoobenthos of the soft bottoms in the 1970s, its recovery to pre-crisis levels in the 2010s was noted. Despite the difference in the aforementioned phyto- and zoobenthos dynamics, habitat in the 4025 km² area of the botanical sanctuary of national importance “Zernov’s Phyllophora Field” was recognised as Critically Endangered (CR) within the European Red List of Habitats. In this context, the goal of the present study is to clarify the applicability of the CR category to the entire benthic complex of ZPF water area and to assess the current biocoenotic structure and habitat ordination of the zoobenthos on soft bottoms of the ZPF water area in the current conditions of Black Sea de-eutrophication. The obtained results indicate the presence of one biocoenotic complex (Mytilus galloprovincialis) and three subcomplexes in the zoobenthos of ZPF, where the bivalves Mytilaster lineatus, Modiolula phaseolina, as well as Polychaeta are the next most important subcomplex-forming taxa. Throughout all studies of ZPF, relative stability in the biocoenotic representation of the bottom fauna—with the dominance of M. galloprovincialis—has been observed. Due to the current levels of development in both the soft-bottom macrofauna and assemblages of unattached alga Phyllophora, two different habitats were proposed for identification in the water area of the botanical sanctuary. The first habitat – “Aggregations of unattached red algae Phyllophora in the central part of the northwestern shelf of the Black Sea" – was degraded and can be classified as a CR habitat. The second one – “Pontic circalittoral biogenic detritic bottoms with dead or alive mussel beds, shell deposits, with encrusting corallines and attached foliose sciaphilic macroalgae” – represents the soft-bottom biotope and was associated with the biocoenotic complex M. galloprovincialis, proposed for classification as Least Concern. In accordance with three biocoenotic subcomplexes of complex M. galloprovincialis, the spatial position of the three subhabitats was determined on the soft-bottom in the water area of ZPF.

Trapezountian Pontic Greek in Etoloakarnania

2020 ◽  
pp. 1-13
Author(s):  
Spyros Armostis ◽  
Louiza Voniati ◽  
Konstantinos Drosos ◽  
Dionysios Tafiadis
Keyword(s):  
20Th Century ◽  
Black Sea ◽  
Second Generation ◽  
Native Speakers ◽  
Asia Minor ◽  
The Black Sea ◽  
Historical Reconstruction ◽  
Standard Term ◽  
The One

The variety described here is Pontic Greek (ISO 639 name: pnt), and specifically the variety that originates from Trapezounta in Asia Minor (present-day Trabzon in Turkey) as spoken today in Etoloakarnania, Greece by second-generation refugees. The term ‘Pontic Greek’ (in Greek: ) was originally an etic term, while Pontians called their language by other names, mainly [ɾoˈmeika] ‘Romeika’ (Sitaridou 2016) but also [laziˈka] ‘Laz language’ (Drettas 1997: 19, 620), even though Pontians and Laz people do not share the same language, the latter being Caucasian. Nowadays, is the standard term used not only by researchers, but also by native speakers of Pontic Greek born in Greece to refer to their variety (but see Sitaridou 2013 for Romeyka in the Black Sea). Pontic Greek belongs to the Asia Minor Greek group along with other varieties, such as Cappadocian Greek (e.g. Horrocks 2010: 398–404; Sitaridou 2014: 31). According to Sitaridou (2014, 2016), on the basis of historical reconstruction, the Pontic branch of Asia Minor Greek is claimed to have been divided into two major dialectal groups: Pontic Greek as spoken by Christians until the 20th century in Turkey and Romeyka as spoken by Muslims to date in Turkey. Triantafyllidis (1938/1981: 288) divides Pontic varieties, as were spoken in Asia Minor, into three dialectal groups, namely Oinountian, Chaldiot, and Trapezountian, the latter consisting of the varieties that were spoken at Trapezounta, Kerasounta, Rizounta, Sourmena, Ofis, Livera, Tripolis, and Matsouka in Asia Minor (Trabzon, Giresun, Sürmene, Of, Yazlık, Tirebolu, and Maçka respectively in present-day Turkey). However, Triantafyllidis does not explain his criteria for this classification (Chatzissavidis 2012). According to one other classification (Papadopoulos 1955: 17–18; Papadopoulos 1958: $\upzeta$ ), the variety that was used in Trapezounta belongs to the dialectal group in which post-stressed /i/ and /u/ delete along other varieties, such as e.g. the ones that were spoken in Chaldia (present-day Gümüşhane), Sourmena, and Ofis (as opposed to the rest of Pontic varieties, such as the one of Kerasounta, in which those vowels are retained). Trapezountian Pontic Greek can also be classified with the group of varieties that retain word-final /n/, such as the varieties of Kerasounta and Chaldia, as opposed to the varieties that do not retain it, such as the ones of Oinoe (present-day Ünye) and (partially) Ofis (Papadopoulos 1958: θ).

scholarly journals Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf – is there any recovery after eutrophication?

2013 ◽  
Vol 10 (6) ◽  
pp. 3943-3962 ◽  
Author(s):  
A. Capet ◽  
J.-M. Beckers ◽  
M. Grégoire
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Interannual Variability ◽  
Black Sea ◽  
Sea Surface ◽  
The Black Sea ◽  
Northwestern Shelf ◽  
Bottom Waters ◽  
Seasonal Hypoxia ◽  
Bottom Hypoxia

Abstract. The Black Sea northwestern shelf (NWS) is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D) coupled physical–biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981–2009), and to differentiate its driving factors (climatic versus eutrophication). Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981–2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS – which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers – and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the interannual variability of H is explained by the combination of four predictors: the annual riverine nitrate load (N), the sea surface temperature in the month preceding stratification (Ts), the amount of semi-labile organic matter accumulated in the sediments (C) and the sea surface temperature during late summer (Tf). Partial regression indicates that the climatic impact on hypoxia is almost as important as that of eutrophication. Accumulation of organic matter in the sediments introduces an important inertia in the recovery process after eutrophication, with a typical timescale of 9.3 yr. Seasonal fluctuations and the heterogeneous spatial distribution complicate the monitoring of bottom hypoxia, leading to contradictory conclusions when the interpretation is done from different sets of data. In particular, it appears that the recovery reported in the literature after 1995 was overestimated due to the use of observations concentrated in areas and months not typically affected by hypoxia. This stresses the urgent need for a dedicated monitoring effort in the Black Sea NWS focused on the areas and months concerned by recurrent hypoxic events.

Nutrient distribution in the Bosphorus and surrounding areas

2002 ◽  
Vol 46 (8) ◽  
pp. 59-66 ◽  
Author(s):  
E. Okuş ◽  
A. Aslan-Yilmaz ◽  
A. Yüksek ◽  
S. Taş ◽  
V. Tüfekçi
Keyword(s):  
Chlorophyll A ◽  
Black Sea ◽  
Nutrient Dynamics ◽  
Lower Layer ◽  
Water Quality Monitoring ◽  
Nutrient Concentrations ◽  
The Black Sea ◽  
Sea Of Marmara ◽  
Nutrient Distribution ◽  
Northwestern Shelf

As part of a five years monitoring project “Water Quality Monitoring of the Strait of Istanbul”, February-December 1999 nutrient dynamics of the Black Sea-the Sea of Marmara transect are studied to evaluate the effect of discharges given by deep disposals. Through a one-year study, upper layer nutrient concentrations were generally under the effect of northwestern-shelf Black Sea originated waters. This effect was strictly observed in July, when the upper layer flow was the thickest. On the other hand, partly in November but especially in December the northwestern-shelf Black Sea originated water flow was a minimum resulting in similar concentrations in both layers. Nutrient fluctuations also affected the chlorophyll a and POC concentrations as parameters of productivity. The nutrient concentrations decreased with the effect of spring bloom and highest chlorophyll a values were detected in November at Strait stations that did not match to the Sea of Marmara values. This fact represents the time-scale difference between the Black Sea and the Sea of Marmara. On the contrary, high nutrient concentrations in the lower layer (especially inorganic phosphate), and therefore low N:P ratios reflect the effect of deep discharge. Vertical mixing caused by meteorological conditions of the shallow station (M3) under the effect of surface discharges resulted in homogenous distribution of nutrients. Nutrient concentrations of the stations affected by deep discharge showed that the two-layer stratification of the system did not permit the discharge mix to the upper layer.

scholarly journals Engineering geophysical studies in the Black Sea from onboard the R/V Ashamba during 2017

2019 ◽  
Vol 59 (2) ◽  
pp. 319-320
Author(s):  
N. N. Dmitrevskiy ◽  
R. A. Ananyev
Keyword(s):  
Transition Zone ◽  
Continental Slope ◽  
Black Sea ◽  
Water Area ◽  
The Black Sea ◽  
Echo Sounder

In May and October 2017, expeditionary research was carried out in the area of Gelendzhik in the Black Sea at the R/V «Ashamba». The main tasks were the mapping of the seabed and the search for small-sized objects at the bottom of the water area using a WASSP WMB-3250 multibeam echo sounder. Surveys included areal surveying and drawing up bathymetric maps of test sites in Gelendzhik Bay and in the transition zone from the shelf to the continental slope. In addition, the echo sounder was used to search and determine the exact coordinates of the bottom seismograph installed at the seabed near the Divnomorskoye village in May 2016. The article presents the results of the work carried out.

scholarly journals Seasonal dynamics of the hydrophilic bird community of Kruglaya Bay (Sevastopol, the Black Sea)

2016 ◽  
Vol 1 (4) ◽  
pp. 12-21
Author(s):  
V. E. Giragosov ◽  
M. M. Beskaravainy
Keyword(s):  
Black Sea ◽  
Bird Community ◽  
Water Area ◽  
The Black Sea ◽  
Mute Swan ◽  
Calidris Canutus ◽  
Tufted Duck ◽  
Fulica Atra ◽  
Mute Swans ◽  
Common Pochard

The relevance of the study of hydrophilic birds in the urban areas of the Black Sea coast is due to their important role in the coastal biocoenosis structure and the need to preserve biodiversity in the conditions of anthropogenic transformation of Crimean coastal zone. The dynamics of species composition and abundance of birds in Kruglaya (Omega) Bay (Sevastopol) were investigated. The results of regular and episodic monitoring carried out in 1995 and 2005–2016 were used in this work. Quantitative accounting was carried out only in January and February (1–2 times per winter season) in 2005–2008, episodically in 2009–2013 and weekly in December — May 2014/2015 and September — May 2015/2016. Number of specimens per species was registered, and the ratio of young and adult specimens in mute swan (Cygnus olor), sex ratio in mallard (Anas platyrhynchos), common pochard (Aythya ferina) and tufted duck (Aythya fuligula) were determined. Russian and Latin names of birds are represented by L. S. Stepanian. Kruglaya Bay is one of Sevastopol bays which form the northern coastline of the Heraclea Peninsula, and it is a place of seasonal concentrations of hydrophilic birds. The basic morphometric characteristics of the bay are the following: the water area — 0.64 km2, length — 1.3 km, maximum width — 0.8 km, the average depth — 4.5 m. The water area of the bay did not freeze usually, only its inner part was covered with ice in extremely cold winters. Benthic macrophyte species are represented by two associations: Cystoseira crinita and C. barbata on stones and rocks, and Zostera noltii and Z. marina on sandy and silty areas. Two local areas of common reed (Phragmites australis) beds are located in the inner part of the bay. The zoobenthos is a significant part of the food supply of birds and includes 97 species, mainly polychaetes, molluscs and crustaceans. The ichthyofauna is represented by 42 fish species. 51 species of aquatic and semi-aquatic birds across 8 Orders were identified. The winter bird community was most diverse and numerous (32 species: 14 Anseriformes, 7 Charadriiformes, 5 Podicipediformes, 3 Gruiformes, 2 Pelecaniformes, 1 Gaviiformes). Eight species dominate regularly in winters and quantitatively — mute swan, mallard, common pochard, tufted duck, eurasian coot (Fulica atra), black-headed gull (Larus ridibundus), caspian gull (Larus cachinnans) and common gull (Larus canus). Rare species wintering in the Mountain Crimea, including horned grebe (Podiceps auritus), Bewick’s swan (Cygnus bewickii), red-breasted goose (Rufibrenta ruficollis), white-headed duck (Oxyura leucocephala), knot (Calidris canutus), is of great interest. The average ratio of young and adult mute swans in the main wintering period (December — February) was 61 : 39 % in 2014/2015 and 45 : 55 % in 2015/2016, respectively. The ratio of males and females were as follows: in mallard 49.5 : 50.5 % in 2014/2015, and 51.4 : 48.6 % in 2015/2016; in common pochard 54.8 : 45.2 % in 2014/2015, and 60.5 : 39.5 % in 2015/2016; in tufted duck 51.0 : 49.0 % in 2014/2015, and 51.4 : 48.6 % in 2015/2016, respectively. Formation of the winter bird community began in October, sometimes at the end of September when single specimens of mallard, coot, tufted duck, red-breasted merganser (Mergus serrator), black-necked grebe (Podiceps nigricollis) appeared. Common gull, great crested grebe (Podiceps cristatus) and the common pochard come flying in November; the mute swan appears at the beginning of December. Maximum and relatively stable number of most species was typical for January and the first half of February. Maximum number of specimens of all bird species was registered in January 13, 2015 (1288), and February 7, 2016 (1531 specimens). The feeding conditions of Kruglaya Bay allow overwintering of the birds with different feeding specializations. The benthophages (most of Anseriformes and Coot) rank first in species richness (at least 13 species) and in quantitative terms. Five species (black-throated diver (Gavia arctica), great cormorant (Phalacrocorax carbo), common sheg (Phalacrocorax aristotelis), red-breasted merganser, Sandwich tern (Thalasseus sandvicensis)) form the group of ichthyophages. The Grebes occupy an intermediate position between benthophages and ichthyophages: small fish and benthic invertebrates are present in their diet. Four species of gull (black-headed, Caspian, common, Mediterranean gull (Larus melanocephalus)) constitute a group of omnivores. The rare visitors in Kruglaya Bay are zoophagous and omnivorous birds foraging in the surf zone and at shallow depths, such as water rail (Rallus aquaticus), common moorhen (Gallinula chloropus), dunlin (Calidris alpina), knot (Calidris canutus), and herbivores which prefer to feed in terrestrial habitats — red-breasted goose (Rufibrenta ruficollis). The nutritional requirements of birds are compensated to a certain extent by additional feeding carried out by townspeople. In general 30 passing and nomadic species, mainly Charadriiformes (11), Anseriformes (7) and Ciconiiformes (5), were registered. A nesting bird community was absent, and only the nesting of little bittern (Ixobrychus minutus) was registered in 2016 for the first time in city zone. The spring migration took place from late February to May, the autumn migration — from August until the first decade of November. Kruglaya Bay is a valuable natural and ecological educational place and deserves status as a natural park.

scholarly journals Consorts of gastropod Rapana venosa (Valenciennes, 1846) in the Northern Black Sea. Part I: Porifera, Cnidaria, Bryozoa, Chordata

2017 ◽  
Vol 2 (2) ◽  
pp. 20-33 ◽  
Author(s):  
I. P. Bondarev ◽  
N. K. Revkov
Keyword(s):  
Surface Area ◽  
Coastal Zone ◽  
Black Sea ◽  
The Black Sea ◽  
Bottom Fauna ◽  
Depth Range ◽  
Shell Surface ◽  
Rapana Venosa ◽  
The Core ◽  
Rapa Whelk

Gastropod mollusk-invader Rapana venosa (Valenciennes, 1846) in the 1940s took a free ecological niche terminal predator in benthic communities of the Black Sea shelf and has become an important element of the ecosystem. The ability of rapa whelk to have a devastating impact on the biocenosis filter feeders determines the necessity of constant monitoring of this species populations’ state. The study of rapa whelk showed that the ecological role of this species is not limited to predation. Fairly large shell R. venosa is a solid substrate for alga, attached and restrictedly movable (sedentary) benthic animal organisms, among which mobile free-living forms sometimes find shelter. The aim of the work is to describe specific complex of epibiotic organisms formed on rapa-whelk shells, which is regarded as a consortium, where of R. venosa is the core. To study the consort community of R. venosa a sampling was made in 7 regions of the northern part of the Black Sea: 1 – Mamaia beach, Romania, 2 – the north-western part of the Black Sea (NWBS), Crimean sector, 3 – Sevastopol, 4 – Alupka, 5 – Yalta – Alushta, 6 – Karadag, 7 – the Kerch Strait. The sampling in the coastal zone (less then 15 m depth) was carried out by SCUBA and snorkel diving, deeper (up to 40 m) was used “Ocean-50”grab corer was used. Totally of 856 specimens of R. venosa were collected and analyzed. The main bulk of the material in the amount of 750 specimens of R. venosa was sampled in the coastal zone in Sevastopol vicinity (south-western Crimea) at the depth range of 1.5–10.0 m. The collection of the rapa whelk specimens was carried out totally and each specimen was placed in a separate plastic bag indicating the collection area, depth and biotope. Along with the mollusks sampling, visual observations and photographic fixation of hydrobionts in situ were carried out. Based on the research results the taxonomic list of rapa whelk epibiotic organisms was extended and for the first time the taxonomic composition of the mobile forms permanently or temporarily present in the R. venosa consortium was given. The first part of the investigation provides a list of rapa whelk epibionts taxa relating to four (Porifera, Cnidaria, Bryozoa, Chordata) of the seven detected Phyla with indication of sampling depths and bottom type and comments on the frequency of occurrence, the quantity and of their interaction with the consortium core. Phylum Porifera is represented by 1, Bryozoa – 3 Cnidaria – 2 and Chordata – 4 species. The drilling sponge Pione vastifica was found in all the investigated areas, except region 2 (NWBS), with a frequency of 20 to 90 % and the shell surface area damage was up to 100 % (average 30–35 %). Not numerous representatives of Cnidaria were found singly in the region 3 (Actinia equina) and in the region 5 (Diadumene lineata). Bryozoans are the most common group of animal-consorts of rapa whelk present in all the areas of our research. The frequency of their occurrence ranged from 10 to 100 %, the covering area of the shell surface was from 0 to 85 %. More than 90 % of the total surface area of rapana shell cover with bryozoans and their occurrence is in Cryptosula pallasiana. The second bryozoans’ species on development indices is Conopeum seurati, which was found in areas 3, 6 and 7, where the occurrence was up to 30 % and the coverage was up to 25 %. The other 3 species of bryozoans (Schizomavella auriculata, Bowerbankia imbricata, Hippothoa sp.) were found rarely. Representatives of Chordata – 2 species of ascidians (Botryllus schlosseri, Ciona intestinalis) and 3 species of fish (Diplecogaster bimaculata, Parablennius tentacularis, Scorpaena porcus) were recorded singly in regions 2, 3, 5. For the four Phyla of animal organisms considered the consorts list of R. venosa of the sandy bottom biotopes (10 species) is twice more numerous than that of the rocky eco-form (5 species). The organisms studied are of a different degree and nature of relations with the core consortium from commensalism to parasitism. Generalized information on periphyton and total coverage of rapa whelk shells with epibiotic complex is given. The results of the work show that in the Black Sea R. venosa has become an important element of the ecosystem, increasing biological diversity of the bottom fauna due to the formation of its own consortium complexes of epibiontic organisms.

Organic Matter of Bottom Sediments of the Crimean and Caucasian Coasts (Azov and Black Seas)

2021 ◽  
Author(s):  
E. A. Tikhonova ◽  
Keyword(s):  
Organic Matter ◽  
Black Sea ◽  
Bottom Sediments ◽  
Petroleum Hydrocarbons ◽  
Water Area ◽  
The Black Sea ◽  
Pollution Level ◽  
Sea Of Azov ◽  
The Caucasus ◽  
The Sea Of Azov

As part of the 113th cruise of the R/V “Professor Vodyanitsky”, research was conducted on organic pollution of bottom sediments in the coastal areas of Crimea and the Caucasus, as well as the water area in front of the Kerch Strait. Concentration of chloroformextractable substances was determined by the weight method and that of petroleum hydrocarbons was determined using infrared spectrometry. Both in 2020 and 2016 (the 83d cruise of the R/V “Professor Vodyanitsky”), properties of the bottom sediments of the Crimean and Caucasian coasts were typical of the marine soils of this region. This indicates that the studied water areas are generally in good condition. In accordance with the regional classification of bottom sediment pollution, the maximum concentrations of chloroform-extractable substances obtained for both the Black Sea and the Sea of Azov coast indicate pollution level III (23% of analysed samples). These values were found in bottom sediments in the Sevastopol water area (225 mg·100 g-1), in the coastal area of Cape Tarkhankut (120 mg·100 g-1) and Karadag (120 mg·100 g-1), the southern part of the Sea of Azov (125 mg·100 g-1) and Tuapse (110 mg·100 g-1). The content of chloroform-extractable substances in bottom sediments off the Black Sea coast of the Caucasus and the Sea of Azov coast is slightly lower than that off the Crimean coast. Pollution level II is assigned to bottom sediments in 46 % of the samples, with an average concentration of 72 mg·100 g-1 of air-dry solids. The rest (31 %) of the studied area was classified as conditionally clean (pollution level I, i. e. less than 50 mg·100 g-1). There has been a slight increase in the concentration of petroleum hydrocarbons in the bottom sediments of both the Black Sea and the Sea of Azov and their share in the total amount of chloroformextractable substances. In general, the level of pollution of bottom sediments by organic matter remained unchanged if compared with previous years, in particular with the data from 2016

Promising Hydrocarbon Prospects in the Paleogene Formations of the Black Sea Northwestern Shelf, Ukraine

2008 ◽  
Author(s):  
I.V. Nedosekova ◽  
I.V. Karpenko ◽  
G.S. Starchenko ◽  
I.V. Karpenko ◽  
G.S. Starchenko
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Northwestern Shelf
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