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Svetla Stankova, Tzanko Tzankov and Rosen Iliev

Abstract

The Black Sea Neozoic passive continental margin marks the natural „bridge” between the Moesian and Bulgarian continental microplates and the Black Sea oceanic microplatte. It was coming in to being after the saturation between the terrains which are composed the Neo Europe south east part during the Early Paleogene. The subaerial part of the margin includes the most east parts of the South Moesian, Hemus, and Upper Thracian and Sakar-Strandzha morphostructural zones. The subaquatic part of the margin is composed by the consequently orderly step lower to the Black Sea bottom: high shelf zone, lover shelf zone, continental slope and continental foot. The Black Sea Neozoic passive continental margin is characterized by low seismic activity. It is concentrated in some fault zones.

Open access

Juraj Kapusta, Juraj Hreško, František Petrovič, Dávid Tomko-Králo and Jozef Gallik

Abstract

Tatra’s lakes are vulnerable ecosystems and an important element of the alpine landscape. Mainly some shallow lake basins succumb to intense detritus sedimentation, fine fractions of material from the catchment area or to the overgrowing of water level by vegetation. In this paper, changes and dynamics of the 12 Tatra’s lake shorelines that were selected based on the detailed mapping of their extent are pointed out. Changes were assessed by accurate comparisons of historical and current orthophoto maps from the years 1949, 1955 and 2015 – and therefore, based on the oldest and the latest relevant materials. Due to the overgrowing of lakes caused by vegetation, their water surface decreased from −0.9% up to −47.9%, during the examined period. Losses were caused by the overgrowing of open water surface by the communities of sedges and peat bogs. The most significant dynamics of the shorelines during the last decades were reached by those lakes, into which fine sediments were simultaneously deposited by means of mountain water coarse. These sediments made the marginal parts of the lake basins shallower and accelerated rapid expansion of vegetation to the detriment of the open water surface. The overgrowing of shallow moraine lakes lying in the vegetation zone is a significant phenomenon of the High Tatras alpine landscape. It leads to their gradual extinction, turn into peat bogs and wet alpine meadows.

Open access

Marek Bednář and Bořivoj Šarapatka

Abstract

The article presents a method of selecting critical areas (4th river basin) in terms of landscape degradation, with an emphasis on water retention, from a relatively larger unit (3rd river basin). For this purpose, indicators that point directly or indirectly to soil and landscape degradation or water retention were selected with regard to the scale of processing. The indicators were processed in a multi-criteria context using principal component analysis, which, based on the spatial layout pattern of the indicators, assigns weights of importance. These weights were then subsequently used to calculate the aggregation index, which indirectly indicates the sensitivity of the area to degradation and, in particular, water retention. Two catchment areas of the 3rd order – Čížina and Kyjovka – with different soil, climatic and economic conditions were selected for the study. Among the indicators of water retention in the landscape, our analysis included the share of agricultural land in the total area, the share of arable land, the average size of the field block, soil degradation according to the degradation model, runoff curve number, potential water erosion and surface drainage. The resulting procedure can be used to evaluate smaller areas. For a more detailed solution, a number of other methods and indicators could be used, which are also outlined in the article.

Open access

Anita Ivanković, Nikolina Ćosić, Zrinka Knezović and Višnja Vasilj

Abstract

Blidinje lake is an integral part of the Nature Park Blidinje established in 1995. Blidinje lake is largest mountain lake in Bosnia and Herzegovina (B&H) according to the surface and water supplies. Considering the surface, it is surprising to its low depth and large surface changes.

Eutrophication is defined as the ‘biological effect of increasing concentrations of plant nutrients in aquatic ecosystems’. Eutrophication results in increased primary production or the production of aquatic plants. It can adversely affect the suitability of the use of water resources for other purposes. Metabolism of shallow lakes is extremely specific such as classical connections; algal biomass with a load of nutrients in shallow lakes can have catastrophic effects.

Nutrients that come directly or indirectly into water lead to increase in the amount of algae as well as changes in the composition of phytoplankton, where there is suppression of diatoms and green algae by cyanobacteria.

The values of parameters assessing trophic index (Trophic State Index [TSI]) are total phosphorus, chlorophyll a and transparency. This method that generalises numerous data using mathematical equations allows the expression of trophic level.

On the basis of earlier studies on physical and chemical parameters of water quality in Blidinje lake, Carlson trophic index was calculated, and based on that assessment, trophic level is given.

Open access

Laurent André, Christomir Christov, Arnault Lassin and Mohamed Azaroual

Abstract

The knowledge of the thermodynamic behavior of multicomponent aqueous electrolyte systems is of main interest in geo-, and environmental-sciences. The main objective of this study is the development of a high accuracy thermodynamic model for solution behavior, and highly soluble M(III)Cl3(s) (M= Al, Fe, Cr) minerals solubility in Na-Al(III)-Cr(III)-Fe(III)-Cl-H2O system at 25°C. Comprehensive thermodynamic models that accurately predict aluminium, chromium and iron aqueous chemistry and M(III) mineral solubilities as a function of pH, solution composition and concentration are critical for understanding many important geochemical and environmental processes involving these metals (e.g., mineral dissolution/alteration, rock formation, changes in rock permeability and fluid flow, soil formation, mass transport, toxic M(III) remediation). Such a model would also have many industrial applications (e.g., aluminium, chromium and iron production, and their corrosion, solve scaling problems in geothermal energy and oil production). Comparisons of solubility and activity calculations with the experimental data in binary and ternary systems indicate that model predictions are within the uncertainty of the data. Limitations of the model due to data insufficiencies are discussed. The solubility modeling approach, implemented to the Pitzer specific interaction equations is employed. The resulting parameterization was developed for the geochemical Pitzer formalism based PHREEQC database.

Open access

Dragomir Marchev, Georgi Dimitrov, Nataliya Pavlova and Borislav Stoyanov

Abstract

This article presents a 2D visualization of stellar spectra, obtained in Rozhen NAO.The aim is to convert one-dimensional arrays into two-dimensional images with the possibility of adjusting the degree of gray. This allows us to visualize the curves of the radial velocities and to determine their half-amplitudes even more precisely. The results of the observed stars NSVS 254037 and TYC3621-711 are presented.

Open access

Galina Zadorozhnaya

Abstract

This article examines changes in the spatial distribution of soil penetration resistance in ordinary chernozem (Calcic Chernozem) and in the recultivated soil in 2012 and 2014. The measurements were carried out in the field using an Eijkelkamp penetrometer on a regular grid. The depth of measurement was 50 cm, the interval was 5 cm. The indices of variation of soil penetration resistance in space and time have been determined. The degree of spatial dependence of soil penetration resistance has been determined layer by layer. The nature of temporal dynamics of soil penetration resistance of chernozem and technical soil has been described. A significant positive relationship of the structure of chernozem in the two years of the research has been shown. Significant correlations between the data of different years in the technical soil were found to be mostly negative.

Open access

Florian Kucera, Christian J. Beisser and Patrick Lemell

Abstract

Many studies have yet been conducted on suction feeding in aquatic salamander species. Within the Salamandridae, the crested newt Triturus dobrogicus (Kiritzescu, 1903), occurring from the Austrian Danube floodplains to the Danube Delta, was not subject of investigations so far. The present study examines the kinematics of aquatic suction feeding in this species by means of high-speed videography. Recordings of five individuals of different size and sex while feeding on bloodworms were conducted, in order to identify potential discrepancies among individuals and sizes. Five coordinate points were digitized from recordings of prey capture and twelve time- and velocity-determined variables were evaluated. All specimens follow a typical inertial suction feeding process, where rapid hyoid depression expands the buccal cavity. Generated negative pressure within the buccal cavity causes influx of water along with the prey item into the mouth. Results demonstrate higher distance values and angles for gape in individuals with smaller size. In addition, hyoid depression is maximized in smaller individuals. While Triturus dobrogicus resembles a typical inertial suction feeder in its functional morphology, intraspecific differences could be found regarding the correlation of different feeding patterns and body size.

Open access

Darina Bachvarova, Aleksandar Doichinov and Rayme Abdulova

Abstract

The article presents the results of a study of the soil surface seasonal activity of two species of julidae, widely spread in the Balkan Peninsula: Leptoiulus trilineatus (C.L. Koch, 1847) and Megaphyllum trassylvanicum (Verhoeff, 1897). The material was collected by means of pitfall traps between May 2007 and May 2009 in natural and urban habitats exposed to varying degrees of anthropogenic pressure. In the study period 1474 specimens of L. trilineatus and 618 specimens of M. transsylvanicum were collected. The impact of the soil and air temperature and humidity on the seasonal activity of both species was measured through statistical analysis. The statistical data processing was conducted using SPSS 9.0 and StatPlus 3.5.3 software packages.

L. trilineatus and M. trassylvanicum are polytopic, mesophilic and mesotermic species with year-round activity in the studied area. There is no statistically significant correlation between the degree of anthropogenic impact and the activity of the two species.

Leptoiulus trilineatus shows equal preference for both urban and natural habitats in the studied area. The species demonstrates the typical of all millipedes bimodal activity, which is the highest in spring and the beginning of winter – in the periods from March to May and from November to December. The coefficients of correlation dependence of L. trilineatus activity on the tested abiotic environmental factors are not statistically significant. The Pearson-Brave coefficient which measures the effect of soil humidity on species activity is 0.417, which shows a positive correlation. M. trassylvanicum has the highest frequency in urban biotops such as parks in the urban and suburban areas of Shumen and in the coniferous habitats on the Shumen Plateau. In this area the species demonstrates its highest activity in spring and summer (from February to July). The abiotic factors with statistically significant effect on the soil surface activity of M. trassylvanicum are the soil and air temperature – the values of the Pearson-Brave correlation coefficients are 0.708 and 0.586 respectively.

Open access

Milan Geršl, Tjaša Kanduč, Dalibor Matýsek, Martin Šotnar and Jan Mareček

Abstract

In the field of electric power industry, renewable energy sources, fertilisers, reclamation, and waste management, biomass is widely studied and used. Minerals are present in every step of biogas transformation, but their forms, occurrence, and composition have not been studied yet. However, there is no comprehensive study research that would address the presence of mineral phases in the process of biogas production. This aim of the study is determination of the amount and composition of the mineral phases present in fermentation residues resulting from different production technologies. Digestate mineral composition was analysed using 46 samples from agricultural biogas plants and university testing biogas reactor. The majority of samples contained the amorphous phase. Minority phases consisted of quartz, albite, orthoclase, muscovite, and amphibole. Opal-CT was found in eleven samples (1.26 to 12.1% wt.). The elements present in gas-liquid fluids or in liquids, gases and aerosols within the biogas technology system may create mineral phases, namely the amorphous phase or the crystalline phase under certain conditions. Opal-CT may enter the fermenter as part of plant tissues referred to as phytoliths, or as an unwanted admixture of different origin. It may also originate from the present amorphous SiO2.