Danube Basin Research Articles

Relationships between macrophyte species, their life forms and environmental factors in floodplain water bodies from the Bulgarian Danube River Basin

The composition and structure of macrophyte assemblages in different water bodies from Bulgarian Danube River catchment area for a period of three years were studied. Main environmental variables: water depth and transparency, substrate type, nutrients (ammonium, nitrate, nitrite and total nitrogen, phosphate and total phosphorus) were simultaneously measured. Our aim was to investigate the spatial and temporal variability of macrophyte composition on the taxonomical (species) and functional (life forms) level in relation to environmental factors by means of multivariate analyses (PCA, CCA and RDA). The Bray-Curtis index was also used to investigate species similarities within and between different kinds of water bodies. Hydromorphology and connectivity were the main factors explaining the spatial variations of both species and life forms. The phosphate phosphorus, total nitrogen and temperature were the variables explaining temporal variation of species.

Determination of tritium levels in environmental samples around NIPNE, Romania from 2007 to 2017

National Institute for Physics and Nuclear Engineering (NIPNE) Romania is located in Măgurele and approximately 10 km from Bucharest. A continued surveillance over the past 10 years offers the opportunity to verify the tritium releases, but also for development of monitoring methods. The determined levels are well below the maximum admissible limits for environmental samples. Dose values have no impact on the environment and have an insignificant contribution to the cumulative annual dose. Comparison with global, regional and zonal levels highlights the role played by its emissions in the Lower Danube Basin, the Romanian Plain and the Danube Meadow.

A Joint Soil‐Vegetation‐Atmospheric Water Tagging Procedure With WRF‐Hydro: Implementation and Application to the Case of Precipitation Partitioning in the Upper Danube River Basin

AbstractAtmospheric models such as the Weather Research and Forecasting (WRF) model provide a tool to evaluate the behavior of regional hydrological cycle components, including precipitation, evapotranspiration, soil water storage, and runoff. Recent model developments have focused on coupled atmospheric‐hydrological modeling systems, such as WRF‐Hydro, in order to account for subsurface, overland, and river flow and potentially improve the representation of land‐atmosphere interactions. The aim of this study is to investigate the contribution of lateral terrestrial water flow to the regional hydrological cycle, with the help of a joint soil‐vegetation‐atmospheric water tagging procedure newly developed in the so‐called WRF‐tag and WRF‐Hydro‐tag models. An application of both models for the high precipitation event on 15 August 2008 in the German and Austrian parts of the upper Danube river basin (94,100 km2) is presented. The precipitation that fell in the basin during this event is considered as a water source, is tagged, and subsequently tracked for a 40‐month period until December 2011. At the end of the study period, in both simulations, approximately 57% of the tagged water has run off, while 41% has evaporated back to the atmosphere, including 2% that has recycled in the upper Danube river basin as precipitation. In WRF‐Hydro‐tag, the surface evaporation of tagged water is slightly enhanced by surface flow infiltration and slightly reduced by subsurface lateral water flow in areas with low topography gradients. This affects the source precipitation recycling only in a negligible amount.

Seyf-i Sarâyî’nin Gülistan Tercümesi’nde Devrik Cümleler

Qipchaqs known as Kipchak/Kifcak in the East, Kuman in the West, and Polovest in Russia, lived in the Qipchaq steppe, the Danube river basin, the Balkans, and the MiddleEast throughout their history. They founded the Mamelukes state (1250–1517) in Eygpt, and they created great Qipchaq literature there. The Gulistan, written by Sa’di al-Shiraziy, one of the greatest Persian poets, was translated from Persian to Qipchaq Turkish by Seyf al-Sarayi, a Qipchaq poet. This translation is one of the most important books among all Qipchaq books in terms of being a reflection of basic Mameluke Qipchaq Turkish features. This book, known as the Gulistan Tercumesi in Turkish, was academically prepared for publishing by Ali Fehmi Karamanlioglu during his associate professorship in 1968 in Turkey. In this study, all of the sentences in the Gulistan Tercumesi prepared by Karamanlioglu have been analyzed in terms of their anacoluthons. All of the anacoluthons in the Gulistan Tercumesi have been placed in three categories in terms of their usage: (a) conversations, (b) translations, and (c) other cases. The most common place for anacoluthons in the Gulistan Tercumesi is in conversational sentences, which are very typical in Turkish languages. Because anacoluthons appear in both spoken and written Turkish languages, they are most often found in conversations. However, it is important to note here that the Gulistan Tercümesi is an original work, although it is a translated book. Regular sentences in the Gulistan Tercumesi are more dominant than anacoluthons, which is quite normal in terms of general Turkish rules. In our opinion, this dominance is a result of Seyf’s Turkish language consciousness and his great knowledge of three languages.

Estimation of the long-term cyclical fluctuations of snow-rain floods in the Danube basin within Ukraine

Estimation of the long-term cyclical fluctuations of snow-rain floods in the Danube basin within Ukraine

Level of surface water eutrophication in Danube river basin

Level of surface water eutrophication in Danube river basin

Karst groundwater quantity assessment and sustainability: the approach appropriate for river basin management plans

As a result of the fact that karstified rocks can accumulate large amounts of high-quality groundwater, karst aquifer is considered, throughout the world, one of the most important types of aquifers. Due to their high permeability, but also vulnerability to pollution, these precious groundwater resources need to be properly evaluated and protected. Taking into account heterogeneity and complexity of the karst environment, it is difficult to propose a uniform algorithm for managing karst groundwater, which causes the necessity to most often apply a case-by-case approach. The rules and standards of the EU Water Framework Directive require the development of Management Plans for all, and entire, river basins. Such plans include the estimation of pressures on water quality and quantity and have already been prepared for most basins of the European Union countries. This paper discusses the applied methodology and some of the results that have been obtained through the analyses of quantitative pressure on delineated groundwater bodies within the Danube and Sava River basins in Bosnia & Herzegovina and Serbia. The analyses confirmed the immense potential of karst aquifers in both countries as regards groundwater quantity.

Determination of resident brown trout Salmo trutta features by their habitat characteristics in streams of Serbia

Streams’ order, their width and depth, as well as the water temperature, conductivity, dissolved oxygen contents and pH reaction were recorded for 18 streams of the Danube River basin in Serbia that home brown trout Salmo trutta. For each of them, the number of fish species was recorded, and for brown trout in them the number of cohorts, age-structure, productivity (biomass, annual production and average weight) and growth (von Betalanffy’s growth parameters L∞, t0, K and ø’) were calculated. They were examined in relation to stream’s habitat features. Stepwise multiple regression revealed strong interdependence between habitat variables. Size, i.e., width and depth of streams increased and their oxygen content dropped with increase in their order and rise of the water temperature, and water conductivity was strongly interrelated with order and depth of streams. Increase in streams’ order and their water’s temperature were accompanied with the increase of species number in them, number of brown trout cohorts raised with the water conductivity and dropped with the increase of the alkaline pH value of streams, whereas growth of brown trout was determined by width of streams and their water’s conductivity. However, when analyzed one at a time, very few of habitat and population traits, e.g., stream depth and L∞, varied clearly in streams of either various orders, or conductivity classes, respectively. The notable, but not yet significant variability of almost all other characters implicates their strong and complex acting in concert to determining number of fish species in syntopy, brown trout population, productivity and growth features.

Scale effects on the performance of niche-based models of freshwater fish distributions

Niche-based species distribution models (SDMs) have become an essential tool in conservation and restoration planning. Given the current threats to freshwater biodiversity, it is of fundamental importance to address scale effects on the performance of niche-based SDMs of freshwater species’ distributions. The scale effects are addressed here in the context of hierarchical catchment ordering, considered as counterpart to coarsening grain-size by increasing grid-cell size. We combine fish occurrence data from the Danube River Basin, the hierarchical catchment ordering and multiple environmental factors representing topographic, climatic and anthropogenic effects to model fish occurrence probability across multiple scales. We focus on 1st to 5th order catchments. The spatial scale (hierarchical catchment order) only marginally influences the mean performance of SDMs, however the uncertainty of the estimates increases with scale. Key predictors and their relative importance are scale and species dependent. Our findings have useful implications for choosing proper species dependent spatial scales for river rehabilitation measures, and for conservation planning in areas where fine grain species data are unavailable.

Luminescence chronology of the northeastern Bulgarian loess-paleosol sequences (Viatovo and Kaolinovo)

The key reference loess sequence of Viatovo in NE Bulgaria, lying within the lower Danube basin, records climatic and environmental changes over the last 800 ka. This 20 m thick loess sequence consists of seven loess units (L1 to L7) intercalated by six paleosols (S1 to S6) below the modern soil (S0). The Matuyama-Brunhes palaeomagnetic boundary has been identified in the lowest loess unit (L7). This reference loess sequence remains so far undated by radiometric techniques. Its chronostratigraphy relies only on pedostratigraphic and magnetostratigraphic evidence. This contrasts with the adjacent reference loess sequences of SE Romania (Tuzla, Mostistea, Mircea Vodă) whose luminescence chronology is now securely established up to MIS 8.The aim of this study is to validate the chronostratigraphic framework of the Viatovo loess sequence using the luminescence dating method. For this purpose, the luminescence method is applied to the three upper loess units (L1, L2, L3) from two adjacent sites: the reference site of Viatovo and the nearby site of Kaolinovo, both located in the Ludogorie region (NE Bulgaria) and showing the same superposition of loess (L1 to L7) and interbedded paleosols. Luminescence dating (Infrared stimulated luminescence; IRSL) was carried out using the feldspar fine sand-size grain fraction (60–80 μm), applying the IRSL50 and the pIRIR290 dating techniques. For the equivalent dose (De) determination we used both the SAR post-infrared infrared (pIRIR290) protocol on single aliquots and the multiple-aliquot additive dose (MAAD IRSL50) protocol. The pIRIR290 ages and the fading corrected MAAD-IRSL50 ages are self-consistent. It demonstrates for the first time, that the three upper loess layers (L1, L2, L3) at Viatovo and Kaolinovo were deposited during the marine isotope stages (MIS) 2–4, 6 and 8, thus constraining the youngest well-developed paleosol (S1, a chernozem) to the Last Interglacial. These IRSL50 and pIRIR290 ages are in good agreement with the luminescence ages obtained for (1) the two upper loess layers (L1, L2) from the Harletz sequence in NW Bulgaria and (2) the three upper loess units (L1, L2, L3) from the adjacent SE Romanian loess sequences.The luminescence chronology of the loess sequences is presented along with the pedogenic and magnetic property data. The pedostratigraphic records of the NE Bulgarian and SE Romanian loess sequences show the same palaeoclimatic trends, with progressive aridification during interglacial periods (from S6 to S0).

Characterization of wastewater effluents in the Danube River Basin with chemical screening, in vitro bioassays and antibiotic resistant genes analysis

Averaged 7-day composite effluent wastewater samples from twelve wastewater treatment plants (WWTPs) in nine countries (Romania, Serbia, Hungary, Slovenia, Croatia, Slovakia, Czechia, Austria, Germany) in the Danube River Basin were collected. WWTPs' selection was based on countries' dominant technology and a number of served population with the aim to get a representative holistic view of the pollution status. Samples were analyzed for 2248 chemicals of emerging concern (CECs) by wide-scope target screening employing LC-ESI-QTOF-MS. 280 compounds were detected at least in one sample and quantified. Spatial differences in the concentrations and distribution of the compounds classes were discussed. Additionally, samples were analyzed for the possible agonistic/antagonistic potencies using a panel of in vitro transactivation reporter gene CALUX® bioassays including ERα (estrogenics), anti-AR (anti-androgens), GR (glucocorticoids), anti-PR (anti-progestins), PPARα and PPARγ (peroxisome proliferators) and PAH assays. The potency of the wastewater samples to cause oxidative stress and induce xenobiotic metabolism was determined using the Nrf2 and PXR CALUX® bioassays, respectively. The signals from each of the bioassays were compared with the recently developed effect-based trigger values (EBTs) and thus allowed for allocating the wastewater effluents into four categories based on their measured toxicity, proposing a putative action plan for wastewater operators. Moreover, samples were analyzed for antibiotics and 13 antibiotic-resistant genes (ARGs) and one mobile genetic element (intl1) with the aim to assess the potential for antibiotic resistance. All data collected from these various types of analysis were stored in an on-line database and can be viewed via interactive map at https://norman-data.eu/EWW_DANUBE.

ADCP Discharge Measurements on the River Danube: Post-Processing and Correction of Data

Abstract Accurate measurements and analyses of river discharges are one of the key tasks of hydrology. Nowadays, the traditional methods of discharge measurements are being supplemented or even replaced by novel approaches that utilize state-of-the-art technologies. One approach, which has recently become very popular in the hydrological practice both in Slovakia and abroad, is a method utilizing the Doppler effect of sound waves. In this study, a dataset of 185 discharge measurements on the River Danube was created using a RiverRay portable Acoustic Doppler Current Profiler (ADCP). All the measurements were taken on the River Danube at four different cross-sections in Slovakia. The measurements were processed using the manufacturer’s WinRiver II software and further adjusted in Agila, which is a specialised third-party post-processing software aimed at correcting measurement errors from ADCP discharge measurements. Currently, some but not all countries lying in the Danube basin have included Agila post-processing in their methodologies. This causes problems and disputes between national water authorities when exchanging information about discharge measurements in the border regions. In order to respond to this problem, the main objective of this study was to compare the results of both original and corrected discharges, which were measured under a number of different circumstances, and to propose recommendations about the suitability of using Agila post-processing for discharge measurements of the River Danube.

Water Resources Management Issues in the Danube River Basin District—Examples from Serbia

This paper aims to present water resources management problems in Serbia and recommend possible solutions. Key issues involve water quality and water quantity. Water quality is endangered by organic pollution from different sources and low degree of waste water treatment. Incomplete exploration of water resources availability as well as their inadequate exploitation are the biggest problems related to water quantity. Other problems involve lack of harmonized legislation, insufficient investments in water resources management, inadequate water price, low level of services, the lack of an effective integral water management system, illegal construction in the areas of water sources and potentially floodplains as well as lack of monitoring. In order to deal with these problems and overcome or mitigate their consequences, complex of measures should be implemented in the frame of interdisciplinary and transdisciplinary national and international projects.

Joint efforts for mobility in Danube region

On December 18, 2018, a round table on “Joint efforts for mobility in the Danube region” was held at the Ministry of Infrastructure of Ukraine. The purpose of the round table was to unite and to consolidate the efforts and joint actions of central and local authorities to support inland navigation in the Danube region, as well as to intensify Ukraine’s activities in the implementation of the European Union Strategy for the Danube Region. The European Union Strategy for the Danube Region is a long-term EU policy to address the Danube macro-region. In 2011, it was approved by the European Commission and supported by the European Parliament and the EU Council. According to the strategy, 14 countries of the Danube River Basin by 2020 will have to implement about 200 projects related to four main areas: the Danube Region, the protection of the environment, the promotion of prosperity and the strengthening of its positions. These include, in particular, the achievement of political stability in the region, joint work for security and prevention of crime. The key themes and objectives of the discussion during the round table were as follows: the strengthening coordination between national and regional stakeholders; opportunities for activating Ukraine in priority direction 1A (mobility: inland navigation); creation of joint infrastructure projects within the framework of the Danube Strategy; accelerating the adoption of legislative initiatives on the Ukrainian inland navigation.

Future water quality monitoring: improving the balance between exposure and toxicity assessments of real-world pollutant mixtures

Environmental water quality monitoring aims to provide the data required for safeguarding the environment against adverse biological effects from multiple chemical contamination arising from anthropogenic diffuse emissions and point sources. Here, we integrate the experience of the international EU-funded project SOLUTIONS to shift the focus of water monitoring from a few legacy chemicals to complex chemical mixtures, and to identify relevant drivers of toxic effects. Monitoring serves a range of purposes, from control of chemical and ecological status compliance to safeguarding specific water uses, such as drinking water abstraction. Various water sampling techniques, chemical target, suspect and non-target analyses as well as an array of in vitro, in vivo and in situ bioanalytical methods were advanced to improve monitoring of water contamination. Major improvements for broader applicability include tailored sampling techniques, screening and identification techniques for a broader and more diverse set of chemicals, higher detection sensitivity, standardized protocols for chemical, toxicological, and ecological assessments combined with systematic evidence evaluation techniques. No single method or combination of methods is able to meet all divergent monitoring purposes. Current monitoring approaches tend to emphasize either targeted exposure or effect detection. Here, we argue that, irrespective of the specific purpose, assessment of monitoring results would benefit substantially from obtaining and linking information on the occurrence of both chemicals and potentially adverse biological effects. In this paper, we specify the information required to: (1) identify relevant contaminants, (2) assess the impact of contamination in aquatic ecosystems, or (3) quantify cause–effect relationships between contaminants and adverse effects. Specific strategies to link chemical and bioanalytical information are outlined for each of these distinct goals. These strategies have been developed and explored using case studies in the Danube and Rhine river basins as well as for rivers of the Iberian Peninsula. Current water quality assessment suffers from biases resulting from differences in approaches and associated uncertainty analyses. While exposure approaches tend to ignore data gaps (i.e., missing contaminants), effect-based approaches penalize data gaps with increased uncertainty factors. This integrated work suggests systematic ways to deal with mixture exposures and combined effects in a more balanced way, and thus provides guidance for future tailored environmental monitoring.

Integrating catchment land cover data to remotely assess freshwater quality: a step forward in heterogeneity analysis of river networks

Attempts to obtain information from geospatial data in freshwater ecology is a highly challenging task requiring the development of new concepts and adequate tools. Conventionally, river networks are represented as collections of vectors, but they can also be thought of as a succession of raster cells corresponding to the digital elevation model of the landscape they traverse. Based on the principle that each cell in the river raster collects environmental influences from its upstream drainage basin, we defined a remote measure of the potential of pollution named RWQ (Remote Water Quality). We used the CORINE Land Cover categories found in the catchment area of each cell in the river network grouped by ecological relevance and weighted by their respective areas in the catchment. To refine the index to account for the proximity of potential pollution sources, we tested successive buffers of 1 km up to the full catchment of each investigated point, concluding that the RWQ calculated for the full catchment is the most suitable index. For implementation, we developed RIVERenhancer, a free Python-based ArcGIS tool making possible the enhancement of raster river networks with data extracted from various files. The reliability of RWQ was tested with the aid of in situ measurements of chemical and biological water quality obtained from several sources in Danube basin (Romania and Hungary). The strong correlation with field data shows that this index can be considered a surrogate to depict the quality of freshwater habitats and to analyse network heterogeneity. The strength of this concept comes from taking advantage of the dendritic nature of river networks, opening new directions of operations for large scale approaches concerning important issues in global ecology, biogeography and conservation.

Occurrence of alien spirlin (Alburnoidessp.) in the Neretva river basin

Northern Mediterranean region is characterised by an exceptional richness of the freshwater ichthyofauna. Many fish species of this region are endemic to a single or a few river basins. This is also the case of the Neretva river basin (Adriatic Sea slope), where 17 out of 34 native species are endemic solely to this river basin. However, these unique Mediterranean freshwater ecosystems are fragile and are susceptible to human-induced changes, including introduction of alien fish species. We report here a finding of the 32ndalien fish species in the Neretva river basin, spirlinAlburnoidessp., which was found at two localities in Bosnia and Herzegovina. The spirlin species was identified by molecular means as so far unnamed species with the native range in the Sava river basin (Danube river basin, Black Sea slope). Based on the comparison ofcytochrome bsequences, the introduced population originated most probably from nearby rivers of the Danube basin in Bosnia and Herzegovina (Vrbas and Bosna river basins). Such a high number of alien fish species reported in a single river basin is alarming and pointing to a necessity of raising public awareness, especially among local fishermen.

First record of North African catfish (Clarias gariepinus) in Croatian inland waters

First record of North African catfish (Clarias gariepinus) in Croatian inland waters

Morphological and genetic diversity of Sabanejewia balcanica (Cobitidae, Actinopteri) in Bosnia and Herzegovina

Event Abstract Back to Event Morphological and genetic diversity of Sabanejewia balcanica (Cobitidae, Actinopteri) in Bosnia and Herzegovina Alen Bajrić1, Ivana Buj2*, Avdul Adrović3 and Edina Hajdarević3 1 Faculty of Natural Sciences and Mathematics, University of Tuzla, Bosnia and Herzegovina 2 Faculty of Science, University of Zagreb, Croatia 3 University of Tuzla, Bosnia and Herzegovina Taxonomic position of the Balkan spined loach, Sabanejewia balcanica (Karaman, 1922) is still uncertain. There are pronounced differences in morphological characters among individuals from different populations, which led to description of various populations as species, subspecies and clinal variation. In this investigation we aimed to describe morphological and genetic diversity of S. balcanica in Bosnia and Herzegovina, investigate phylogenetic relationships among populations and get insight into their evolutionary history. The obtained results revealed pronounced genetic structuring inside S. balcanica in Bosnia and Herzegovina and moderate to high genetic diversity contained inside each population. Lineages and sublineages of S. balcanica in Bosnia and Herzegovina diverged during Pleistocene epoch and their evolution was mostly likely shaped by alteration of glaciations with interglacial periods. Based on morphometric characters, investigated populations fall within already reported range for S. balcanica. However, distinctiveness of populations from Brka, Suturlija and Turija Rivers from the remaining populations in their body shapes has been observed and discussed in relation to separate evolutionary history of some populations. Keywords: Balkan spined loach, Danube Basin, evolutionary history, morphometry, population genetic structure Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Poster Topic: TAXONOMY, PHYLOGENY AND ZOOGEOGRAPHY Citation: Bajrić A, Buj I, Adrović A and Hajdarević E (2019). Morphological and genetic diversity of Sabanejewia balcanica (Cobitidae, Actinopteri) in Bosnia and Herzegovina. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00129 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 07 Jun 2019; Published Online: 14 Aug 2019. * Correspondence: Mx. Ivana Buj, Faculty of Science, University of Zagreb, Zagreb, Zagreb, 10000, Croatia, ivaradic@biol.pmf.hr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Alen Bajrić Ivana Buj Avdul Adrović Edina Hajdarević Google Alen Bajrić Ivana Buj Avdul Adrović Edina Hajdarević Google Scholar Alen Bajrić Ivana Buj Avdul Adrović Edina Hajdarević PubMed Alen Bajrić Ivana Buj Avdul Adrović Edina Hajdarević Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Feeding preferences and diet overlap of introduced Atlantic and native Danube lineages of brown trout (Salmo trutta) from Croatia

Feeding preferences and diet overlap of introduced Atlantic and native Danube lineages of brown trout (Salmo trutta) from Croatia