Publications
Institute Of Oceanology
Vol. 3 Varna 2001
Bulgarian Academy of Sciences
MARINE PHYSICS:
Sea level surface variations in Bourgas bay
Dobrina Kostichkova, Zdravko Belberov, Ekaterina Trifonova, Diana Grudeva
Available existing data base (1928 - 1989) and published scientific results (1975 - 1985) in the sphere of sea level surface variations with diverse genesis: tidal, storm surge and high periodical (barical) variations were checked, processed and analyzed.
It was noticed during the review process that the extreme storm event of Feb. 1979 was not included probably due to the lack of data at the flooded Bourgas mareograph station. Hence, for determination of regime characteristics of maximum sea levels with normative repetition was used incomplete statistical data row by authors. The mareograph stations of Ahtopol, Irakli and Varna registered highest levels during the same period (1.20 - 1.50 m).
Supplementary statistical processing and correlation analysis has been performed to include it in the statistical row of database and to estimate the water level in Bourgas during the Feb.1979 extreme event.
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MARINE CHEMISTRY:
On the recent dynamics of some chemical parameters along
the Bulgarian sector of the Danube River
Alexander Stoyanov, Galina Shtereva, Anton Krastev, Ognyana Hristova, Lidia
Mihova, Ilia Shterev
През периода юли 1995 . юни 1996 година в района на гр. Силистра са проведени наблюдения (средно 2 пъти месечно) върху качеството на дунавските води по следните показатели: разтворен кислород (DO), алкалност, биогенни елементи (N, P), суспендирано вещество и метали. Получените ртезултати са сравнени с данни на други автори от предишни периоди по отношение на сезонната динамика, положението на минимумите и максимумите.
DO се влияе от температурните промени и максимума на хлорофила, когато се наблюдава пресищане на водата с DO. Биогените бележат ниски стойности през лятото и високи през есенно-зимния или зимно-пролетния сезон. Динамиката на Fe и Mn показва доминиране на теригенния внос. Суспедираните форми на металите, POC и Si са в пряка зависимост от речното ниво. Въпреки намаленото постъпване на N и P с българските притоци степента на еутрофизация на речните води остава висока.
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On the state of the Beloslav lake during 1998 - 1999 period.
Galina Shtereva, Ognyana Hristova, Tatyna Nikolova, Boryana Dzhurova
The paper presents the results of a study on the water and sediment chemistry of the Beloslav Lake during two seasons (summer and autumn). The following parameters are analyzed at three stations: S ?, dissolved oxygen (DO), alkalinity, nutrients (P and N), metals, and organic C and P in sediments. The comparison with the data of 1990 reveal a tendency of decreasing of P in waters. The monitored waters correspond to water quality standards (by the national law) but a level of eutrophication is still high. A hipoxy in the bottom layer is observed in the summer as in 1990. At present the Provadijska River and the chemical plants are the main sources of pollution for investigation area as in previous periods.
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MARINE GEOLOGY:
Holocene sediments from West part of Black Sea
Ivan Genov, Vesselin Peychev
Извършено е изследване на холоценски седименти от 18 станции от западната част на Черно море, опробвани с мултикорер по време на 52-рия рейс на НИК .Проф. Водяницки., проведен през месец септември 1998 г. Определен е литоложкият състав на пробите, скоростта на седиментация и е извършен биостратиграфски анализ. На част от пробите е определен зърнометричният състав, плътността и водното съдържание. Холоценските седименти са разгледани като асоциация от автохтонни компоненти, формирани при специфични физикохимични и биохимични условия и алохтонни компоненти, постъпили от източници на теригенен материал и трансформирани под въздействието на постседиментни фактори.
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Lithological features of the upper Holocene in the east
part of Black sea
Ivan Genov
В статията са изнесени данни от литолого-стратиграфски анализ на ядков материал, събран по време на 55-ия круиз на изследователския кораб .Проф. Водяницкий. (20.09. . 13.10.2000 г.). Данните включват скорости на седиментация, стратиграфско разчленение, литоложка характеристика и др. и са за източната част на Черно море. Добавена е и кратка информация от химически анализи за определяне на органичен въглерод, органичен фосфор и неорганичен фосфор на част от ядките.
В заключение е направено обобщение на изнесените данни. Скоростите на седиментация на континенталния шелф, континенталния склон и подножие в източната част на Черно море са над около 14 cm/1000 г., а в източната дълбоководна котловина са ниски до 11 cm/1000 г., но те могат да бъдат и по високи от 20 cm/1000 г. близо до вала Андрусов.
Тектонската активност и/или активността на морските течения могат да бъдат маркирани чрез нестабилна седиментация установена в дълбоководните геоложки ядки от източната част на Черно море. Такива области, установени по време на споменатата по-горе експедиция, са пред Крим, Грузия и източната част на вала Андрусов..
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Classification of the faults on the Bulgarian shelf, to the North of Kamchia
river mouth and the adjacent land
Ivan Genov
Classification of the faults to the North of Kamchia river mouth in the Bulgarian part of the Black sea and neighbouring land is made. The Genesis of the faults on the basis of existing investigations is described and generalized. The faults are differentiated by depth of penetration, formation of geological structures and other features.
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Morphohydrographic analysis of the coastal zone in the
Bulgarian Black Sea littoral
Stoyan Keremedchiev
On the basis of morphohydrophic and morphometric characteristics of the catchment areas in the Bulgarian Black Sea littoral are determined main factors for erosion activity, coefficient of sedimentation and morphological specificity of the coastal and submarine relief.
Three rates of erosion segmentation are delimited by comparative cartographic method. Erosion-terrigenous ingredients in formation of accumulative deposits are determined.
Morphological classification of the coastal zone on the basis of morphostructural specificity and lithostratigaphic description in formation of types and inclination of the submarine slopes is done.
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Development of the terrace complex of the coastal zone
of the Bulgarian Black Sea shore
Stoyan Keremedchiev, Zhivelina Cherneva
The authors? attempt to clarify the geo-morphological and genetic peculiarities of the terrace complex is based on ample morphographic and lythologic material. The origin of the various terrace types has been highlighted as well as their distribution and positioning along the profile of the coastal zone. An attempt has been made to outline the corresponding dating of the terrace levelling and their morphological dependence of the lythostratigrphic and tectonic decomposing processes. Because of the insufficient data on the fauna distribution, as well as the lack of clear morpho-stratigraphic levelling of the terraces in the coastal zone under observation, the prevailing conclusions are towards their predominantly geo-morphological origin.
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Morphology and dynamics of the Pechora Sea coasts
Stanislav Ogorodov
Based on analysis of geological and geomorphological structure and wind-energy calculations, classification and zonation of the Pechora Sea coasts were carried out and sediment drift directions were determined. The Varandei area ? the most industrially developed coastal region of the Pechora Sea ? is used as an example of technogenic impact upon dynamics of coastal systems reducing their stability.
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Features in the dynamics and development of the Dobrudzha
beaches
Ekaterina Trifonova, Margarita Stancheva
The part of the northern Bulgarian Black Sea coast between cape of Sivriburun and cape of Shabla is the area, when the rate of abrasion is highest. There are three beaches - Durankulak- North, Durankulak-Krapets and Shabla in this area. The beaches have similar features and the common correspondence can be observed in their development.
Three kinds of data are used in the present investigation: coastline data (1976, 1990), grainmetric and carbon contains of the beach sand samples data.
Some typical features can be trace in development of the beaches, as well, east exposition, low indentity coefficient, typical sickle-like form, besides the southern part of the beach is more sea-ward, that the northern one. The coast is open to the wind waves from NE, E and SE. All of this features cause common correspondence in the beaches development: sand accumulation in the southern part of the beach and shore cutting in the northern one; the accumulation have considerably high area, then the shore cutting; shore cutting is typical for the northern parts with the E-exposition; coarse and medium sands are predominant; coarse grains are placed close to shore line and front of the beach; Averaged grain size is varied between coarse in the northern parts and medium in the southern one; sand carbon contains is vary between 75 and 100 %, that is the result of it mussel origin
Performed investigations show - there is relatively equilibrium of the beach dynamics. The trend is toward increasing, although the cape areas split these beaches indicate highest rate of abrasion in the Bulgarian Black Sea Coast.
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Some negative trends in the development of the underwater
slope in front of the beach of camp Europe
Hristo Nikolov Mariya Mutafova
Besides their role as a recreational resource the Bulgarian Black Sea beaches appear also as a peculiar buffer preventing coastal destruction caused by the wave impact. The recent data available in the Institute of Oceanology show that about 54 % from the total 63 beaches have decreased in area for the last 25-30 years. During these years the construction of hydrotechnical facilities like groins gains impetus which has changed the hydrodynamical regime and the dynamics of the beach creating material. A number of negative processes occurred as disturbance of the long-shore sand transport (Golden Sands and Akutino), increase of the abrasive processes in the neighbouring sites and beaches (beach Journalist and Akutino), disturbance in the total dynamic equilibrium of the coastal zone and underwater coastal slope (Golden Sands, Pomorie and camp Europe). Conditions for development of different negative hydro- and lithodynamical processes were created. These phenomena provoke disputes on the effectiveness of the coastal protection activities. The random investigations conducted in the Institute of Oceanology by Nikolov, Dachev, Keremedchiev during 80-ies and 90-ies indicate both positive and negative development in the hydro- and lithodynamical processes but up to now purposeful regime investigations of these processes have not been carried uot. Some of the investigations conducted by Dachev, Nikolov (1977), Dachev, Cherneva (1979), Nikolov (1980) are concerned with the problems of the long-shore sand transport and the state of the beaches. Later on, Nikolov, Simeonova, Marinovaal. (1985, 1988), Nikolov, Keremedchiev (1990) dealt with the issues of coastal protection and beach development along the Bulgarian Black Sea coast whereupon a tendency of shortening of some of these beaches has been registered. Confusing fact appears to be that this phenomenon is accompanied by deepening of the underwater coastal slope in front of some beaches (Golden Sands Resort, Pomorie beaches and camp Europe) where second survey was carried out. The causes and the range of these processes are still not explained due to the lack of systematic measurements of the coastal underwater slope within and out of the zone of the existing marine structures. It is quite possible that such deepening of the underwater slope might also exist in front of other regions with marine structures for which there is not enough data available at present. Considering the fact that a significant number of our beaches decrease in area we have to look for the basic reasons of this unfavourable phenomenon which might lead to natural disasters in the near future such as an increase of the abrasive processes and activation of the land-sliding ones with unpredictable economical consequences.
The main purpose of the report is to point out the changes occurring in the beach adjacent underwater slope of camp Europe within the range of the existing marine structures. Investigations have been carried out by taxometric and levelling measurements of the beach and the underwater slope. Diving observations and bottom sediment sampling were also included.
The analysis shows that the sector studied exhibits up to 2 m depth depending on the adjacent underwater slope within the range of the marine structures. This deepening has caused an unfavourable impact on the beach which resulted in shortening of its area. This negative process is due to the unfavourable impact of the marine structures, the deficiency of beach nourishing material, sea level rise as a consequence of the "green-house" effect combined with wind-wave conditions and least but not last the exploitation of the beach resources.
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The Bulgarian Black Sea coast according to medieval charts
Preslav Peev, Vesselin Peychev
In this feature medieval charts are compared with the contemporary bathymetric map of littoral zone of the Bulgarian Black Sea coast. There are analyses the dynamical processes, which has been on coastal zone and occurred in the relief. It is made attempt for identification of the position of islands, which are representation on the medieval charts, but today is not exist.
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MARINE BIOLOGY:
Recent ecosystem trends along the Bulgarian Black Sea
coast
Kamen Prodanov, Snejana Moncheva, Asen Konsulov, Ludmila Kamburska, Tsonka Konsulova,
Kristina Dencheva
На базата на многогодишни данни за качествения и количествения състав на фитопланктона, зоопланктона и зообентоса са проследени процесите, довели до съвременното състояние на черноморската екосистема пред българския бряг. Посочено е влиянието на промишления риболов върху настъпилите промени, включително и за навлизането в Черно море на два нови вида ктенофори . Mnemiopsis leidyi и Beroe ovata. В тази връзка е отбелязано, че след 1989 г. черноморската екосистема е под доминиращото влияние на Mnemiopsis leidyi, а след 1997 г. . на Beroe ovata, която е хищник спрямо M. leidyi. Подобряването на екологичната обстановка в Черно море се обуславя и от намалената концентрация на биогенни елементи вследствие на икономическия колапс на крайбрежните държави. В резултат на всичко това уловите на риба варират в широки граници в зависимост от състоянието на рибните запаси и прилаганото риболовно усилие през съответните години.
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Determination of the Black Sea anchovy stocksduring the
period 1968 - 1993 by Ivanov?s combined method
Liudiya Ivanov, Marina Panayotova
Чрез комбинирания метод на Иванов са определени по възраст, поколения и години експлоатационните, общите и размножителните запаси на хамсията; коефициентите на риболовна смъртност (F) и утилизация (U) на запасите по численост и биомаса, като са използвани данните за възрастовия състав на сумарните улови на всички черноморски държави през периода 1968/69 . 1992/93 г. Установена е висока степен на съвпадане на динамиката на общите начални запаси на възраст 0+ - 4+, на началните размножителни запаси на възраст 1 - 4 г. и на средните коефициенти на риболовната смъртност на възраст 0+ - 4+, определени по комбинирания метод на Иванов и по метода на VPA (P r o d a n o v, S t o y a n o v a, M i k h a i l o v, 1998). Потвърждават се главните фактори (въздействието на ктенофората Mnemiopsis leidyi и свръхриболовът в местата на зимуване на хамсията), довели до рязкото спадане на запасите от хамсия през периода 1989/90 . 1991/92 г.
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An analysis of the zooplankton state in the lake of Varna.
Kremena Stefanova
The publication focuses on the development of the zooplankton qualitative and quantitative parameters in the region of Varna Lake. The aim is to compare the state of the zooplankton community during winter - spring season of three consecutive years (1998 - 2000) as well as
tracing its trends of development under the influence of the eutrophication processes.
Representatives of the meroplankton complex as also of Cladocera, Copepoda and Rotatoria dominate in the quantitative structure of the zooplankton. Significantly less is the number of species as Noctiluca scintilance, Aurelia aurita, Oicoplreura dioica and Mnemiopsis leidyi.
The comparative analysis of zooplankton data shows that the highest mean values of biomass were registered in 1998 (3578.961 mg.m-3), approximately 1.5 lower is the biomass for 1999 (2519.39 mg.m-3) and almost four times lower for 2000 (839.438 mg.m-3).
According to the study of the zooplankton community an improvement of the state of the zooplankton coenose in the lake ecosystem would be possible through recovery by adapting to the alternative natural conditions. However, the positive tendencies are arbitrary owing to still highly expressed variability of the biomass of the zooplankton community and the vulnerability of the lake ecosystem to the anthropogenic factors.
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Growth parameters of the Black Sea sprat (Sprattus sprattus
L.) during the period 1998 - 2000 along the Bulgarian Black Sea coastе
Marina Panayotova
Настоящата работа изчислява някои основни характеристики за популацията от черноморска трицона (Sprattus sprattus L.) като размерен и възрастов състав, параметри и характер на нарастването, зависимост между теглото и дължината и индекса на угоеност по Фултон. Установено е, че нарастването през периода 1998 . 2000 г. е алометрично. Стойностите на параметъра n, характеризиращ нарастването в зависимостта между теглото и дължината, варират от 2.750 до 3.296. Установено е, че през есенно-зимния сезон, зависимостта между дължината на тялото и индекса на Фултон е обратнопропорционална, докато през пролетно-летните месеци същата е пропорционална. Параметрите в уравнението на Von Bertalanffy, изчислени по отношение на дължината за периодите ноември 1998 г. . март 1999 г. и април . октомври 1999 г. са, както следва: Lt = 14.81{1-exp[-0.201(t + 2.795)]} и Lt = 16.64{1-exp[- 0.146(t + 3.212)]}.
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Migration, seasonal and spatial distribution of Manx Shearwater,
Puffinus puffinus in the Black Sea basin
Dimitar Nankinov
Миграциите, сезонното и пространственото разпределение на обикновения буревестник в Черноморския басейн са доста сложни, имат хранителен характер и зависят от годишния жизнен цикъл, от особеностите в биологията, миграциите и промените в числеността на видовете риби, с които той се храни. Основна храна на обикновения буревестник тук са черномоската и азовската хамсия (Engraulis encrasicholus ponticus и E. e. maeoticus), шпротът (Sprattus sprattus) и атерината (Atherina mochan pontica). През пролетта обикновеният буревестник се насочва най-вече към северозападната, северната и източната част на Черно море, задържа се дълго в Керченския пролив, понякога следи рибните стада край западния морски бряг. Със затоплянето на времето мигрира към вътрешността на морето и обитава огромни пространства. В края на лятото и есента прониква все по-често в Азовско море. През есента разпръснатите по цялата морска акватория обикновени буревестници мигрират към бреговете на полуостров Крим и Кавказ, където се формират зимовищата на черноморската и азовската хамсия. Обикновеният буревестник посещава Черноморския басейн масово през лятото и пролетта, когато са регистрирани съответно 53.73 % и 46.01 % от срещаните през годината индивиди. Най-много са птиците през април (32.74 %) и юни (27.06 %). След това те постепенно намаляват, като през зимата в Черно море има най-малко обикновени буревестници.
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MARINE ENGINEERING:
An express method for plankton abundance detection in
sea water.
Atanas Palazov
The increased abundance of plankton under the influence of high level eutrophication of Black Sea as a stratified basin, result in a dramatic change of the optical properties of the water masses especially in the coastal regions. Light attenuation in the water could be used for plankton abundance assessment and communities aggregation down the water column.
A special device has been constructed based on measuring of an optic system directed light beam attenuation in water. The relationship between light attenuation and total plankton abundance and chlorophyll 'a' fluorescence is evaluated in laboratory experiments on sea water samples with molded plankton biomass.
A good relationship between light attenuation and total phyto- and zooplankton biomass as well as chlorophyll 'a' fluorescence has been established.
The results may serve as a calibration of the device for in-situ application.
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Methods of ecological monitoring of the sea bottom
Traian Traianov
As it`s well known, the anthropogenous pollution of the sea-shore waters, affects most negatively upon the sea bottom.
That is why ecological monitoring of the sea bottom appears to be an important part in studying the sea environmental conditions.
A classification of advanced methods, concerning investigation of the sea bottom conditions based upon computerizing treatment of video and photo images is given.
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A general model of solid piezoceramic scheme
Atanas Atanasov
A model of solid piezoceramic scheme is presented. It is received as a result of the equations describing the work done for changing of electrical axis when straight piezo effect and for changing of mechanical axis when opposite piezo effect. The model includes a detail description of admission-outlet parameters of the three basic constructive four-polars too, which are in its structure. The parameters characterize the electrical part, mechanical part as well as the transformation which is valid when admitting the straight and opposite piezo effect. The advantage of the model is that it can be applied to detailed modulation of the mechanical part of the model with electrical ?mechanical analogies. Not less is the importance of the model as a base when working out the acoustical systems which work in conditions of radiating or accepting as well as in static or dynamic conditions.
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