Black Sea Coastal Area Research Articles

Seasonal changes of nutrients and oxygen in the Bulgarian Black Sea coastal area

The paper discusses the seasonal dynamics of nutrients and oxygen during the period 1995-1998 in comparison to the previous periods. This study is based on monthly and seasonally monitoring in the 3-20 n. m. zone along the Bulgarian Black Sea area. The investigation reveals certain shifting of seasonal maximums (minimums) and a trend of decreasing oxygen saturation, phosphorus and silicon in the last few years.

Dynamics of macrozoobenthos in the Southern Bulgarian Black Sea coastal and open-sea areas

The paper presents results of analysis of 96 macrozoobenthic samples, collected on a seasonal basis in Bourgas Bay and in open-sea areas offshore Cape Emine (Bulgarian Black Sea) in 1996 and 1998. In total 96 taxa were established, distributed in four groups: Polychaeta, Mollusca, Crustacea and “Diversa”. The average density of populations was 1756 ind.m-2 with a predominating abundance of Polychaeta species. The average biomass estimated was 183.02 g.m-2, formed mainly by representatives of Mollusca. The latter species were measured together with the shells, which appraised their individual weights. Seven of the species found had a coefficient of constancy more than 50%. These were the most adapted species to the environmental conditions of the investigated areas. The quantitative and qualitative assessments in this study demonstrate an increasing tendency in the parameters obtained (density, biomass, species diversity) in comparison with previous investigations in the early 1990-s, when intensive anthropogenic influence was widely perceived to misbalance the Black Sea ecosystem.The method of Warwick (1986) applied to characterize the water quality of the studied areas allowed us to define them as rather clean or moderately polluted aquatories.

Determination of caesium and natural radionuclide concentrations in sediments, algae and water on the Bulgarian Black Sea coast

Determination of anthropogenic and natural radionuclide distribution along the Bulgarian Black Sea coastal area has been performed by low level gamma spectrometry. Results were obtained for different types of environmental samples: sea bed sediments, eight types of algae species and sea water. Monitoring for 35 sampling sites has been performed from 1991 to 1996. A comparison between the results of nuclide content in algae and sediments was made. The data obtained show that radionuclide concentrations depend strongly on the sediment nature (sand, sandy, silt, slime). Small variations of nuclide content in sand and sandy sediments are obtained, while the variations for slime and silt sediments are greater. The concentrations of artificial and natural gamma emitters in algae depend mainly on the algae species type. The content of most natural radionuclides in algae is close to the LLD except those for the species Bryopsis plumosa. The results for the nuclide concentration values in Black Sea sediments and algae will enable the creation of a database and assessment of radionuclide transfer and accumulation trends in marine ecosystems.

Changes in chemical parameters in the Bulgarian Black Sea coastal area as an indication of the ecological state of the environment

In the present paper the main trends in the principal chemical parameters and the phytoplankton communities in the close coastal area are discussed, aimed at evaluating the present ecological state of the environment and water quality in comparison with historical data. The results reveal a decrease in the content of PO4 and Si, while there is no apparent trend in the N-NO3 variability. In seasonal terms a change in the minima and maxima of some parameters is evident, and a seasonal dynamic closer to the natural annual cycle in the Black Sea. A decrease in the average annual phytoplankton biomass is established, especially pronounced during the summer period. The results suggest a positive sign of evolution of the environmental characteristics of the coastal zone, which should be treated rather tentatively due to the still high level of nutrients and the capacity of the ecosystem to produce and maintain high phytoplankton biomass.

La Turquie : une littoralisation partielle et ambiguë

Spatial disparities in Turkey show three kinds of dual oppositions : coastal regions versus interior regions, but also developed West versus under- industrialized East and rural areas versus cities organized in a hierarchized urban network. This article aims to point out recent trends in development levels, economic activities and demographic dynamics. If a western «crescent of winning regions» confirms the trend towards littoralization, it does not concentrate all the socio-economic growth and leaves aside the Black Sea coastal area.

Changes in chemical parameters in the bulgarian black sea coastal area as an indication of the ecological state of the environment

In present paper the main trends in the principal chemical parameters and the phytoplankton communities in the close coastal area are discussed, aimed at evaluating the present ecological state of the environment and water quality in comparison with historical data. The results reveal a decrease in the content of PO 4 and Si, while there is no apparent trend in the N-NO 3, variability. In seasonal terms a change in the minima and maxima of some parameters is evident, and a seasonal dynamic closer to the natural annual cycle in the Black Sea. A decrease in the average annual phytoplankton biomass is established, especially pronounced during the summer period. The results suggest a positive sign of evolution of the environmental characteristics of the coastal zone, which should be treated rather tentatively due to the still high level of nutrients and the capacity of the ecosystem to produce and maintain high phytoplankton biomass.

Determination of caesium and natural radionuclide concentrations in sediments, algae and water on the bulgarian black sea coast

Determination of anthropogenic and natural radionuclide distribution along the Bulgarian Black Sea coastal area has been performed by low level gamma spectrometry. Results were obtained for different types of environmental samples: sea bed sediments, eight types of algae species and sea water. Monitoring fur 35 sampling sites has been performed from 1991 to 1996. A comparison between the results of nuclide content in algae and sediments was made. The data obtained show that radionuclide concentrations depend strongly on the sediment nature (sand, sandy, silt, slime). Small variations of nuclide content in sand and sandy sediments are obtained, while the variations for slime and silt sediments are greater. The concentrations of artificial and natural gamma emitters in algae depend mainly on the algae species type. The content of most natural radionuclides in algae is close to the LLD except those for the species Bryopsis plumosa. The results for the nuclide concentration values in Black Sea sediments and algae will enable the creation of a database and assessment of radionuclide transfer and accumulation trends in marine ecosystems.

Contacts Between the Steppe and Agricultural Tribes of Central Asia in the Bronze Age

Understanding the interaction between the steppe and agricultural tribes of Central Asia in the Bronze Age and the possible migrations in the sixteenth—ninth centuries B.C. is of paramount significance for the resolution of the problem of Indo-European origins and the localization of their original homeland. Since the nineteenth century, it has generally been accepted that the Indo-European homeland was within the confines of Europe, delimited either by the northern Black Sea coastal area [Prichernomor'e] or by a triangle between the Rhine, the Danube, and the Dnieper. It was assumed that the Indo-Iranian nationalities had left the original homeland toward the east, into the Eurasian steppes, where later a part of them (the ancestors of the Scythians, Sauromatians, Massagetai, and Saka) remained, while others moved on to the south and migrated through the territory of Central Asia into India and Iran. More recently, two leading linguists—V. V. Ivanov and T. V. Gamkrelidze [22, pp. 80-92]—have suggested that the homeland of the Indo-Europeans was found in Western Asia. They consider that during the second half of the second millennium B.C., groups of Indo-European speakers migrated in several waves through Iran and Central Asia to the north, into the northern Black Sea coastal area, and subsequently settled throughout Europe. The last to come from Iran, as late as the eighth century B.C., were the Iranian-speaking Scythians and Saka. According to either scenario, Central Asia occupied a key position in the history of either all of the Indo-Europeans or of only the Indo-Iranians. In which direction the migrations took place and to what extent they were mass migrations remain subject to discussion; the linguistic material does not provide an answer to these questions. Their resolution must be addressed through archeological data.

Studies on the vegetation history of Lake Varna region, northern Black Sea coastal area of Bulgaria

On the basis of pollen analytical investigations of two cores from Lake Varna and Lake Beloslav, the vegetation history of the Lake Varna region is traced back to the beginning of the 6th millennium B.C. A two-fold zoning system is used whereby the pollen diagrams are divided into pollen zones, based on tree migration patterns, and settlement periods. Pollen zone 1 is characterised by the absence of Carpinus betulus and Fagus sylvatica. The spread of hornbeam started at ca. 6500 B.C. (pollen zone 2) and beech at ca. 6200 B.C. (pollen zone 3), the latter being the last tree to spread into the region and considerably enrich the forests of the study area. Of the many pollen taxa representing plants that are favoured by open habitats and hence potentially indicative of human impact, only a few taxa are regarded as reliable indicators of human activity. These include above all Triticum-type, and also Secale and to a certain extent Plantago lanceolata, Rumex and Polygonum aviculare. The spatial pattern of settlements is somewhat different in the areas represented by the two profiles. At both sites the first period of settlement occurred during the 6th millennium B.C. (early Neolithic). After the Neolithic period, the main settlement periods of the Eneolithic and the Early and Middle Bronze Age are recorded. On the other hand, land-use history during the Greek and Roman periods is poorly recorded. Studies on the stratigraphy, diatoms and molluscs indicate that the sixth Black Sea transgression (6500–5800 B.C.), which reached −10 m, had considerable influence on the limnological environment.

GEOGRAPHICAL PROBLEMS OF SOCIALIST ECONOMIC INTEGRATION

The impact of Soviet-bloc economic integration on the spatial structure of the national economies is considered, with particular reference to the interior zone and the frontier areas of member countries. In the case of the Soviet interior, the Comecon integration program has thus far affected mainly the European portion of the USSR. However, as a result of the growing flow of energy and raw materials to Eastern Europe and the increasing number of joint Comecon resource development projects, the Asian areas of the Soviet Union are also being drawn into the integration process. When it comes to frontier areas, several types are distinguished, ranging from the intensive cross-border interaction in the industrial frontier district shared by East Germany, Czechoslovakia and Poland to the potential interplay between Black Sea and Baltic coastal areas. The industrialization of western frontier areas of the Soviet Union is discussed as part of Comecon integration.