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Applicability of Control Region of Mitochondrial DNA for Assessment of Turbot Populations Along the Bulgarian Black Sea Coast

Author(s): Petya Ivanova,Nina Dzhembekova,Ivan Atanassov,Krasimir Rusanov,Violin Raykov,Ivelina Zlateva,Maria Yankova / Language(s): English Publication Year: 0

Turbot is a valuable commercial fish species classified as endangered. Knowledge of the level and distribution of genetic diversity in turbot is important for designing conservation strategies for their sustainable survival and to preserve their evolutionary potential. Mitochondrial control region sequences were investigated to evaluate variability in population genetic structure of one population along the northern Black Sea coast. 19 CR haplotypes were found in the Shabla population, which were shared with turbot haplotypes, previously described for the Black Sea and the Mediterranean. A pattern with a high level of haplotype diversity (h = 0.954 ± 0.022) and a very low level of nucleotide diversity (π = 0.00563 ± 0.00063) indicated a high number of closely related haplotypes and suggested that this population may have undergone a recent expansion. Tajima’s D test and Fu’s FS test both suggest recent population growth. The haplotypes found in the Shablа population were typical for the north Black Sea populations and could be used for distinguishing the population along the Bulgarian Black Sea coast.

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Open Source GIS Decision Support Tools for Wildfire and Flood Natural Hazards with Embedded Interactive Training Resources

Author(s): Stefan Stefanov,Nina Dobrinkova,Emilia Tosheva / Language(s): English Publication Year: 0

Training of volunteers that participate in natural hazard suppression measures is very important and time consuming. The volunteers do not have unlimited amount of time to dedicate on educational activities. Thus, interactive training platforms are the next step of the training processes. In our paper we will describe an open source Geographic Information System (GIS) tool specifically designed to support decision making for field operations in cases of natural disasters. The training activities for the tool implementation were based on Google G-Suite cloud application. The GIS application was developed to deliver field situation alerts in operational room and G suite was used before the field work as preparatory training for the teams working with it. The combination of the online tools described in the paper is presented as potential first step of real time volunteer training system that in future can be further elaborated and improved.

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Seismicity Patterns Associated with Earthquakes on the Balkan Peninsula

Author(s): Emil Oynakov,Dimcho Solakov,Irena Aleksandrova,Jordan Milkov / Language(s): English Publication Year: 0

Statistical analysis was performed, which revealed statistical parameters of the seismic setting before the earthquake in the region of Crete (01.04.2011 with coordinates 26.56oE, 35.64oN; Ml = 6.2, h = 63 km and T0 = 13: 29: 10.5 ). For this purpose, the spatial and temporal changes in the b-value and the value of the Z-seismic lull were estimated. The temporary change in the b-value shows that the average value of b decreased from 1.75 ± 0.02 between 1985 and 2002 to 1.4 ± 0.02 between 2003 and 2011. A significant decrease in the b-value and clear anomalies of calm in the Z-value in early 2011 were also observed in several neighboring areas. The epicenter of the earthquake falls in an area with a relatively low value of the a-parameter estimated for the entire previous period. In the study area, the abnormal decreasing trend of the b-value may be an indicator of increased stress, and the increasing trend of the Z-value may indicate areas of calm before the studied earthquake.

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Parameters of the Seismic Risk for Blagoevgrad Region, Bulgaria

Author(s): Petya Trifonova,Dimcho Solakov,Stela Simeonova,Metodi Metodiev,Stefan Florin Balan / Language(s): English Publication Year: 0

The present study investigates the characteristics of seismic sites of some of the NOTSSI monitoring network stations, based on microseismic noise. Nakamura's method of the spectral ratio of the horizontal to the vertical components of the seismic noise (H / V), directly related to the S-wave velocity of distribution (Vs) at the observed site was used for calculating the station repairs. The spectral H / V ratio of the seismic noise for 11 seismic stations is calculated, combined with geological data bellow each station. The values of A0 - site-effect, f0 - resonance frequency and h - depth of reference at the most contrasting resonance boundary were obtained. Attention is paid to seismic instruments and sensors

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Geoarchaeological Research in the Area of the Cape Shabla Using Unmanned Aerial Vehicles, North Bulgarian Black Sea Coast

Author(s): Bogdan Prodanov,Preslav Peev / Language(s): English Publication Year: 0

This paper aims to set out the role of using aerial remote sensing and marine hazard can play in informing responses to global challenges of coastal cultural heritage and enhancing the sustainable development of coastal zones. Aerial remote sensing and photogrammetric approaches are an integral part of modern archaeological research. In the last two decades of the century, a significant change in approaches to archaeological research has taken place: from direct fieldwork and excavation to remote sensing. In Bulgaria, this scientific discipline is quite new and it is in its infancy. However, during the last few years, the Institute of Oceanology – BAS conducted such types of investigations and a lot of new data have been collected. For this initial survey has been chosen a heritage site on the Bulgarian seashore. The studied area is the archaeological site Caron Limen/Caria at the Cape Shabla and it is determined as highly hazardous to coastal erosion. A systematic archaeological study of the topographic evolution of the coast in association with the functionality of case study area and other coastal facilities during Late Antiquity and Medieval Ages provides new data on the development of coastal life and especially the nature of sea exploitation in the context of maritime commerce.

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Earthquake Scenarios for the City of Ruse

Author(s): Dimcho Solakov,Stela Simeonova,Plamena Raykova,Boyko Rangelov,Constantin Ionescu / Language(s): English Publication Year: 0

Earthquakes are the deadliest natural disasters affecting the human environment. Global seismic risk and vulnerability to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Furthermore, uncontrolled growth of mega cities in highly seismic areas in the world is often associated with the construction of buildings and infrastructure, inconsistent with the regional seismo-tectonic features and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk.In the present study a deterministic earthquake scenario (expressed in macroseismic intensity MSK) for the city of Ruse is generated. The study is guided by the perception that usable and realistic, based on both local seismic history and tectonic conditions, ground motion maps have to be produced for urban areas. The scenario maps account soil amplification effects using the geotechnical zonation of the considered urban area.

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Complex Assessment of the Urban Earthquake Risk

Author(s): Dimitar Stefanov / Language(s): English Publication Year: 0

The impact of earthquakes in urban areas is a complex problem compounded by multi-hazard and consequential risk issues, enormous inventory of vulnerable physical elements and the attendant socio-economic problems. An approach for assessment of urban earthquake risk is presented. Rational urban risk predictions and expected losses from major earthquakes in the future serve the basis and also provide strong reasons for the pro-active risk mitigation activities. The proposed approach is based on a combination of numerical values for the determined levels of consequences in the three considered areas (social consequences, material consequences, economic losses).

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Assessment of Landslide Susceptibility and Hazard along the Northern Bulgarian Black Sea Coast

Author(s): Plamen Ivanov,Vladislav Zaalishvili,Rosen Nankin / Language(s): English Publication Year: 0

The Black Sea coast is one of the regions of Bulgaria with distribution of a significant part of the Bulgarian landslides. The analysis of the factors influencing the stability of the coastal slopes shows that they have a higher concentration and more intensive total impact on the northern part of the Bulgarian Black Sea coast, where most of the larger landslides are located. In this study, the Mora and Vahrson method was applied to estimate the landslide susceptibility along the northern Bulgarian Black Sea coast. This method is based on evaluation of various local factors for slope instability which are estimated using a Geographic Information System. The purpose of the study is to produce a landslide susceptibility map and to locate landslide-prone areas for this region.

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Assessment of Empirical Relationships between Beach-Face Slope and Sediment Size Using Field Data (Burgas Bay Case)

Author(s): Petya Eftimova,Nikolay Valchev,Bogdan Prodanov,Nataliya Andreeva,Todor Lambev,Liubomir Dimitrov / Language(s): English Publication Year: 0

The study examines the relationships between the beach-face slopes and sediment sizes for several coastal stretches located in Burgas Bay using limited field data, and explores the applicability of a number of previously developed formulations for local geomorphic, lithologic and wave conditions. Knowledge on the clear dependence between considered parameters is of particular importance for many engineering applications such as calculation of maximum run-up, shoreline changes, beach berm erosion potential, and assessment of coastal flood and erosion hazards. The results have shown that none of the considered empirical relationships can be used straightforwardly, although some of them might be considered for future analysis. Hence, it is necessary to enrich the database with wider ranges of beach-face slopes, sediment sizes coming from areas with different wave exposure and morphodynamics state in order to elaborate a reliable native relationship suitable for local to regional specifics of the western Black Sea coast. This underpins the importance of regular coastal monitoring.

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An Earthquake Catalogue for Bulgaria and Adjacent Areas since 1981

Author(s): Dimcho Solakov,Stela Simeonova,Plamena Raykova,Irena Aleksandrova / Language(s): English Publication Year: 0

A homogeneous earthquake catalogue for Bulgaria and adjacent areas covering the period 1981–2019 is presented. The existing catalogues (including instrumental seismicity) for Bulgaria, covering the time period 1981–2000, were updated for the time period 2001-2019 using instrumentally determined focal earthquake parameters. In the present update catalogue, MW is calculated for the entire period 1981–2019 applying the regression equations converting magnitude scales used in Bulgarian seismological routine practice (Md and MP) to the most reliable and widely used scale of magnitude, i.e. the seismic moment magnitude, MW. Thus, a magnitude homogeneous catalogue concerning MW scales is presented. The extended catalogue contains 645 independent events. The completeness test revealed that the catalogue is complete for moment magnitudes larger than or equal to 3.2 for the last 39 yr.

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Aggregated Tsunami Scenario for Karpathos Island

Author(s): Lyuba Dimova,Reneta Raykova,Alberto Armigliato,Gianluca Pagnoni,Stefano Tinti / Language(s): English Publication Year: 0

Karpathos is the second largest of the Greek Dodecanese islands. Historical data such as the event of 9 February 1948, indicate that this area is prone to earthquakes and tsunamis. In this study we evaluate the tsunami hazard for the Karpathos Island by means of a scenario-based technique. We take into account tsunamis generated by three main seismic sources in agreement with local tectonics and historical records. The code UBO-TSUFD is used for all numerical simulations. Tsunamis are computed in several domains with different resolution for a better calculation of the maximum coastal wave height and tsunami inundation. Tsunami parameters for each individual scenario are used to construct a unique aggregated scenario, which help us to evaluate the inundation zone. The contribution of all scenarios along the coast of Karpathos is studied via synthetic mareograms. It is found that EHA dominates and that the southern Karpathos is more exposed to tsunamis.

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Effect of Saharan Dust Intrusions on Precipitation Chemistry in Bulgaria

Author(s): Emilia Georgieva,Elena Hristova,Blagorodka Veleva / Language(s): English Publication Year: 0

The objective of this work is to investigate the influence of Saharan dust events on the chemical composition of rain samples collected at three sites in Bulgaria during 2017-2018. Saharan dust intrusions were identified through a combination of satellite retrieved aerosol data and results from dust forecasting models and from backward trajectory model. The chemical composition of the samples (acidity pH, conductivity EC, main ions and elements) is analysed in view of the direction of the approaching air masses – “direct” influence (south-west), and “indirect” influence from other directions and regions, already impacted by Saharan dust. All samples were characterised by elevated values of pH (max 7.4), EC (max 202 µS.cm-1) and Si, Ca, Fe, Mg concentrations. For cases with direct influence Si and Ca values were up to 1.5 and 25 mg.l-1. In most of the indirect cases increased concentrations of sulphate, nitrate and ammonium were observed (up to 39.5, 23.1 and 8.3 mg.l-1)

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PBL Vertical Structure During Extreme Wind Events at Seaside Region of Southern Bulgaria

Author(s): Damyan Barantiev,Ekaterina Batchvarova,Hristina Kirova,Orlin Gueorguiev / Language(s): English Publication Year: 0

round-based remote sensing (GBRS) data collection with Scintec Sodar MFAS was performed in southern Bulgarian Black Sea side from August 2008 until October 2016. These high spatial (10 m) and temporal (10 minutes with averaging time of 20 minutes) resolution measurements of wind and turbulent parameters have been used to explore the vertical structure of the coastal boundary layer during extreme wind events. For this purpose, the ninety-percentile of the two-parameter Weibull distribution of the wind speed at every sodar measurement level from 30 up to 600 m is used as a criterion to define the “rare” values within their statistical distributions and to identify a theoretical extreme wind speed profile (reference profile). On this basis, the extreme profiles during the reviewed period have been determined and their multiple time series have been then used to derive averaged profiles of twelve sodar output parameters under extreme winds conditions.

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Black Sea Holocene Environmental Setting in Respect of Ostrea Edulis Appearance and Loss

Author(s): Ivan Genov,Krasimira Slavova,Tzvetana Nonova,Elena Koleva-Rekalova / Language(s): English Publication Year: 0

Geological and palaeoclimatic Holocene setting in the Black Sea has been traced. This research suggests that the appearance of Ostrea edulis in the Black Sea during the Middle Holocene, not immediately after the invasion of Mediterranean waters, is due to the dynamics of interconnected climate and abiotic parameters of the basin. Although the reasons for the decrease in abundance of the Black Sea population of flat oysters are still uncertain, we attempts, through a comparative analysis of key abiotic factors in the past and today, to suggest that it is quite possible marine ecosystems to respond to modern changes of key climate-related drivers and pollution by changing their habitat and/or extinction. Geological approaches were used to study the abiotic factors of the environment (salinity and temperature) back in time.

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Effect of Organic Matter Loading on Nutrient and Oxygen Fluxes at the Sediment-Water Interface in Different Sedimentary Habitats in Sozopol Bay (Sw Black Sea): a Laboratory Experiment

Author(s): Stefania Klayn,Dimitar Berov,Ventzislav Karamfilov / Language(s): English Publication Year: 0

Coastal benthic sediments play an important role in regulating water column nutrient concentrations and primary production via nutrient regeneration and exchanges at the sediment-water interface. This study aimed to characterize the diffusive benthic fluxes of NH4+, NO3-, PO4-3, and O2 in some of the most common shallow sedimentary habitats (fine and coarse sands, seagrass beds, and unvegetated patches within the seagrass beds) along the Bulgarian coast, and their changes under organic loading, through a laboratory experiment. Nutrient fluxes were dominated by a release of NH4+ to the water column in all sediment types, and a parallel uptake of NO3- by the sediments; both fluxes increased under organic loading, possibly indicating stimulation of nitrate reduction within the sediments. The PO4-3 fluxes were smaller, and the sediments mostly acted as a source for phosphorus under organic loading. O2 was taken up from the overlying water in all treatments and sediment types, and this flux increased under organic loading, probably in relation to the decomposition of the organic matter and spontaneous chemical oxidation of sulphide ions, released during sulphate reduction within the sediments. The study contributes towards the understanding of nutrient cycling and the role of the benthic compartment in Black Sea coastal soft-bottom habitats.

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Assessment of the Natural Landscapes as a Prerequisite for Environmental Risk Assessment and Preparation of Management Plans

Author(s): Petja Ivanova-Radovanova / Language(s): English Publication Year: 0

he article discusses a method for assessment of the quality of the natural landscapes in one of the Nature parks in Bulgaria – Rila Monastery Nature Park – as a good practice for the evaluation of the quality of natural resources. The methodology for Rapid Landscape Assessment presented, had been initially developed for the purpose of the development of the management plan of Rila Monastery Nature Park. Significant amount of information from the field have been generated and analyzed by multi-disciplinary team in a relatively short period of time. It was proved that the approach of rapid assessment is a good practice for cost-effective, rapid and efficient assessment of natural resources. Thus, the methodology can be used in environmental risk assessment of different sites of natural and cultural interest because such sites are normally not only underestimated and also under pressure from different kinds of developments and time constrains.

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Seismicity on the Territory of Bulgaria and Surroundings Recorded by NOTSSI for the Period 2017-2019

Author(s): Dragomir Dragomirov,Emil Oynakov,Valentin Buchakchiev,Jordan Milkov / Language(s): English Publication Year: 0

A map of epicenters of 411 earthquakes with magnitude Mw >= 2.5 that occurred from 2017 to 2019 in Bulgaria and surroundings (sector outlined by latitude = 41o- 44.5o N and longitude = 22o- 29o E) registered by NOTSSI is presented. Analysis is done on the distribution of the events through time and space, magnitude and depth. The events frequency progression is analyzed for the whole studied period and then compared with each year separately. Generalized analysis is proposed as to what can contribute to variations in the data for the studied period. Catalog of earthquakes with magnitude Mw >= 3.5 is applied.

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Intrinsic Oscillations of River Stream Flows Determined by ARIST Method

Author(s): Yavor Chapanov / Language(s): English Publication Year: 0

The river streamflows analyses can be successfully used in water resource planning and management, depending on the needs of the wide range users. It is possible to use these applications in several general directions: as informal, qualitative guidance for water managers, stakeholders and decision makers and prediction about long-term drought variability; for quantitative assessments of long-term hydrologic variability and assessment the severity and duration of drought cycles; as direct inputs into hydrologic models of a water system, etc. The long-term oscillations of the river streamflows are influenced mainly by the solar activity and climate interaction, whose variations often consist of synchronous cycles. The intrinsic oscillations of Danube and Don streamflows are determined by the recently created autoregressive method ARIST. These oscillations are compared with the intrinsic oscillations of solar and climate indices and mean Black Sea level variations. Conclusions about the use of intrinsic oscillations in floods or drought prediction are made.

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Initial Assessment of Composition, Abundance, Spatial Distribution and Hotspots Identification of Floating Macro-Litter in the Bulgarian Black Sea Waters

Author(s): Violeta Slabakova,Ivelina Zlateva,Krasimira Slavova / Language(s): English Publication Year: 0

The present research is focused on composition, density, distribution and identification of accumulative areas of floating marine litter (FML) in the Bulgarian Black Sea coastal, shelf and offshore waters. Macro-debris abundances were determined in compliance with MSFD protocol for visual observations based on fixed-width strip transect method. Six floating litter monitoring surveys were carried out between 2017 and 2019. Over 144 hours of visual observations were performed in a total of 288 transects, covering an overall survey area of 7.52 km2. 1320 litter items were identified and classified during the campaigns of which 90% were detected as plastic materials. The presence of floating debris was observed throughout the entire study area with density ranging from 0 to 1750 items km-2 and average density of 170 items km-2. Unexpectedly marine litter concentration patterns were evenly distributed among the studied regions with some specifics at certain sites.

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Endemic Forests in Danger: Land Use Shifts and Accompanying Impacts upon the Natural Flood Storage Reservoirs along the North Bulgarian Black Sea Coast

Author(s): Iliyan Kotsev,Bogdan Prodanov / Language(s): English Publication Year: 0

Longozes represent endemic forests native to the East Balkans. Key factors for their existence are the humid subtropical climate with mild winters and the river inundations occurring twice-yearly. These hygrophilous forests play an essential regulatory role in the runoff peaks by ensuring a crucial ecosystem service as flood storage reservoirs. Nowadays, because of highly decreased and fragmented areals, longozes are red-listed as critically endangered. Hence, they are subject to preservation in compliance with the EU Habitats Directive and Annex 1 of Bulgaria’s Biodiversity Act. Aim and objectives of the study herein are: to investigate the spatio-temporal changes in the longoz forests’ areals along the North Bulgarian coast; to analyze the consequences of the anthropogenic impacts upon the river runoff; to provide a generalized assessment of the longozes’ contemporary flood retention capabilities. Topographic maps from the late 19th century were integrated in GIS to reconstruct the longozes’ historical extents by on-screen digitizing of the areas of interest. Analogous procedures were applied to such from the mid-1970s, a time frame correlating with the Socialist extensive development of Bulgaria’s coast. The areas’ historical land cover as in the late 1980s was further refined using Landsat imagery. These historic data sets were chronologically compared to the longozes’ contemporary extents, available as up-to-date cadastral data. The comparisons were executed using GIS crosstabulation techniques. The analyses demonstrate the ubiquitous decrease of the longozes due to overexploitation of the wood resources, land use shifts, resort construction, decreased river runoff, etc. These findings imply for a deteriorated environmental status, impaired flood storage capacity and the inability of the woods to act as a regulator of the peak ourflows nowadays, well correlating with the recent extreme coastal floods with fluvial origin.

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