Danube Basin Research Articles

Smernice za uvođenje bioloških sistema za revitalizaciju zagađenih i prečišćavanje otpadnih voda u strateška dokumenta u Srbiji

Long-term courses of water protection and management are based on the fact that Serbia belongs to the region of UNECE countries (UN Economic Commission for Europe) while most of its territory belongs to the Danube River Basin where countries have established multilateral coordination and cooperation in water management. Since the Republic of Serbia is currently in the process of joining the EU, it is obliged to gradually align its strategic decisions in the field of water to the documents that apply to EU member states. The degree of the state's readiness to join the EU will be assessed based on the adequate introduction of internationally accepted principles of water management into the strategic documents and their establishment and implementation at the state level and within international cooperation in this area. Serbia will not be granted EU membership unless it invests significant funds in wastewater and polluted water treatment, as this is one of the priorities in meeting the criteria to open Chapter 27. The introduction of biological systems into the standard water treatment infrastructure provides higher levels of environmental protection and contributes to the integration of environmental requirements, opinions and principles into the plans and programs that encourage and promote sustainable development. The paper will present the current level of alignment between EU and Serbian water-related legislation and propose specific guidelines for the introduction of biological systems for the treatment of polluted water in strategic documents in Serbia.

Practici depoziţionale non-funerare La Tène târziu în sud-vestul României. Descoperirile de la Glogova şi Desa / Non-funerary depositional practices during the Late La Tène in southwestern Romania. The discoveries from Glogova and Desa

Practici depoziţionale non-funerare La Tène târziu în sud-vestul României. Descoperirile de la Glogova şi Desa / Non-funerary depositional practices during the Late La Tène in southwestern Romania. The discoveries from Glogova and Desa

Some remarks on socketed axes of the Passau type

Among artefacts from a private collection there is a bronze socketed axe which resembles the Passau type, originating from an unknown locality. Since the type was first defined in 1935, its definition tended to be extended to cover axes of other variants, and as a result, apart from those decorated with three arched planes (wings), axes ornamented with 1 to 4 arched ribs have also been included into this type. In recent years, however, the name has practically fallen out of use in archaeological literature. A review of relevant publications indicates that both the Passau type proper and the variants decorated with ribs should be dated to a broad timespan of HaA2–HaB3. The earliest assemblages, mostly hoards, occur in the middle Danube basin, and the younger ones in the upper Danube and upper Elbe basins. The closest analogies to the privately-owned axe discussed here are stray finds from Bavaria and Austria. Their chronology falls within HaA2–HaB2, perhaps with a focus on HaB2.

Description of a new species of Phoxinus from the upper Krka River (Adriatic Basin) in Croatia (Actinopterygii: Leuciscidae), first discovered as a molecular clade.

Using morphometric, meristic and qualitative characters, we confirmed a specific status of a clade discovered based on molecular data only. The newly described species Phoxinus krkae has a very local distribution in the upper Krka River but is easily morphologically distinguished from geographically neighbouring species with much wider ranges: Phoxinus lumaireul, Phoxinus marsilii and Phoxinus csikii. Phoxinus krkae is well differentiated in statistical analyses and differs from other species of Phoxinus in northern Adriatic Sea drainages and right-bank tributaries of the middle and lower River Danube by a combination of characters, none of them unique: caudal peduncle length 1.9-2.2 times minimum depth of caudal peduncle; upper lip not projecting beyond lower lip; rostral fold absent; total number of scales in lateral series 74-84; lateral line incomplete and interrupted, commonly 17-49 (< 60% of total number of scales in lateral series) with no or few canal segments on posterior body and caudal peduncle; scales on belly extending forward to over middle of distance between pelvic-fin base and pectoral-fin origin; patches of breast scales commonly connected by scattered scales or forming 1-3 regular rows of scales; total vertebrae commonly 38-39 (22 + 17, 22 + 16 or 21 + 17). The study reveals unrecognised morphological diversity within the group and provides the groundwork for future taxonomic study in Phoxinus in the Adriatic region and the Danube Basin.

A study of the endohelminths of the European perch Perca fluviatilis L. from the central region of the Danube river basin in Slovakia.

The European perch Perca fluviatilis L. serves as a host of different endohelminths of Trematoda, Cestoda, Nematoda, and Acanthocephala. Its natural range covers freshwater basins throughout much of Europe, including the Danube. Since information about endohelminths of European perch from this international river basin has been rather sporadic, the parasitological examinations of 700 perch from the central region of the Danube river basin in Slovakia were performed in October 2017 and April 2018. The larval stages of Triaenophorus nodulosus (Cestoda) were found in cysts located in the perch liver and adults of Proteocephalus percae (Cestoda) were isolated from the intestine. The larval stages of Eustrongylides sp. (Nematoda) and metacercariae of Clinostomum complanatum (Trematoda), both potential causative agents of fish-borne zoonoses, were found in the musculature. Spatial and seasonal differences in the occurrence of currently detected helminths were discussed with data on biological and environmental conditions of particular sampling site.

Comparative study of statistical methods to identify a predictor for discharge at Orsova in the Lower Danube Basin

ABSTRACTThe aims of this study are to investigate the influence of large-scale atmospheric circulation quantified by indices such as the North Atlantic Oscillation index (NAOI), the Greenland-Balkan Oscillation index (GBOI) and blocking-type indices on the Lower Danube discharge. We separately analysed each season for the 1948–2000 period. In addition to the statistical linear procedure, we applied methods to quantify nonlinear connections between variables, as mutual information between predictors and predictand, using Shannon’s information entropy theory. The nonlinear correlation information between climate indices and discharge is higher than that obtained from the linear measure, providing more insight into real connections. Also, the non-stationarity of the link between variables is highlighted by spectral coherence based on wavelet analysis. For the physical interpretation, we analyse composite maps over the Atlantic-European region. The most significant influence on the discharge of the Lower Danube Basin is given by the GBOI and blocking-type atmospheric circulation over Europe.

Beneficial land use change: Strategic expansion of new biomass plantations can reduce environmental impacts from EU agriculture

Society faces the double challenge of increasing biomass production to meet the future demands for food, materials and bioenergy, while addressing negative impacts of current (and future) land use. In the discourse, land use change (LUC) has often been considered as negative, referring to impacts of deforestation and expansion of biomass plantations. However, strategic establishment of suitable perennial production systems in agricultural landscapes can mitigate environmental impacts of current crop production, while providing biomass for the bioeconomy. Here, we explore the potential for such “beneficial LUC” in EU28. First, we map and quantify the degree of accumulated soil organic carbon losses, soil loss by wind and water erosion, nitrogen emissions to water, and recurring floods, in ∼81.000 individual landscapes in EU28. We then estimate the effectiveness in mitigating these impacts through establishment of perennial plants, in each landscape. The results indicate that there is a substantial potential for effective impact mitigation. Depending on criteria selection, 10–46% of the land used for annual crop production in EU28 is located in landscapes that could be considered priority areas for beneficial LUC. These areas are scattered all over Europe, but there are notable “hot-spots” where priority areas are concentrated, e.g., large parts of Denmark, western UK, The Po valley in Italy, and the Danube basin. While some policy developments support beneficial LUC, implementation could benefit from attempts to realize synergies between different Sustainable Development Goals, e.g., “Zero hunger”, “Clean water and sanitation”, “Affordable and Clean Energy”, “Climate Action”, and “Life on Land”.

Characterisation of the floods in the Danube River basin through flood frequency and seasonality analysis

Floods are natural disasters that cause extreme economic damage and therefore have a significant impact on society. Understanding the spatial and temporal characteristics exhibited by floods is one of the crucial parts of effective flood management. The Danube River with its basin is an important region in Europe and floods have occurred in the Danube River basin throughout history. Flood frequency analysis (FFA) and seasonality analysis were performed in this study using the annual maximum discharge series data from 86 gauging stations in order to form a comprehensive characterisation of floods in the Danube River basin. The results of the study demonstrate that some noticeable clusters of stations can be identified based on the best-fitting distribution regarding FFA. Furthermore, the best-fitting distributions regarding FFA for the stations in the Danube River basin are generalized extreme values (GEV) and log Pearson type 3 (LP3) distributions as among 86 considered gauging stations, 76 stations have one of these two distributions among their two best fits. Moreover, seasonality analysis demonstrates that large floods in the Danube River basin mainly occur in the spring, and flood seasonality in the basin is highly clustered.

Geochemical signature of sources, recycling and weathering in the Last Glacial loess from the Rhône Valley (southeast France) and comparison with other European regions

Pleistocene loess of the Rhone Valley and Provence region, disconnected from the two main European aeolian systems (North European Loess Belt and Danube basin), are of interest to test the impact of source variability, grain size sorting, weathering and sediment recycling on the geochemical composition. The concentration of major, trace and rare earth elements in loess and potential sources was analysed through Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and ICP-Mass Spectometry (ICP-MS). Analyses show a genetic relationship between loess and the Ca-rich river sediments from the Alpine Ice Sheet (AIS). The loess of Provence show distinctive properties with a higher CaO and MgO content and a higher Europium anomaly (Eu/Eu*), suggesting sources richer in dolomite together with a contribution from mafic rocks (Alpine ophiolite complex). The homogeneous loess composition, compared to alluvial sources, reflects particle mixing during transport in the atmosphere. At the European scale, the geochemical composition of loess changes according to regions, but remains consistent within each region. Such variability is mostly related to the composition of rocks outcropping in respective catchments and especially in areas covered by ice sheets. The Chemical Proxy of Alteration (CPA) and Rb/K ratio suggest a weak chemical weathering linked to the cold and dry conditions typical of the Last Glacial. Recycling of older aeolian formations possibly caused loess enrichment in resistant minerals and quartz, especially for loess derived mostly from the abrasion of aeolian sand (Aquitaine).

The age and paleoenvironment of a late Miocene floodplain alongside Lake Pannon: Rodent and mollusk biostratigraphy coupled with authigenic 10Be/9Be dating in the northern Danube Basin of Slovakia

We present new age constraints for the late Miocene Volkovce Formation of Slovakia, alluvial facies that accumulated adjacent to Lake Pannon. Facies analysis and authigenic 10Be/9Be dating was undertaken at the Bernolákovo and Triblavina localities while the latter outcrop also yielded additional small mammal and mollusk assemblages as well as remains of flora. The results of seven radiometric dating ages yielded a weighted mean age of 9.65 ± 0.61 Ma for the Triblavina outcrop and 8.85 ± 0.32 Ma for the Bernolákovo outcrop. The small mammal assemblage at the Triblavina outcrop is indicative of the lowermost MN11 zone, which in the Western European standard definition suggests an age of <8.9 Ma. The ~0.1 Ma inconsistency between absolute dating and biostratigraphic dating at the Triblavina outcrop might be explained either by the variation of initial 10Be/9Be ratio in the depositional environment or/and by diachronous development of the mammal faunas across the Europe. The mollusk assemblage at this outcrop indicates the paleoenvironment of freshwater lakes affected by rivers with evidence for a nearby riparian forests; it may be roughly correlated with Papp's lithostratigraphic units G and H defined for the Pannonian stage in the Vienna Basin. Our results provide a detailed insight to the late Miocene stratigraphy and terrestrial environments alongside the Lake Pannon shoreline.

Irrigation Water Use in the Danube Basin: Facts, Governance and Approach to Sustainability

Abstract In this paper we assess the irrigation water use in the Danube Basin, highlight its complexity, identify future challenges and show the relevance for a basin-wide integrative irrigation management plan as part of a more holistic and coherent resource policy. In this sense, we base our integrative regional assessments of the water-food-energy nexus on insights from an extensive review and scientific synthesis of the Danube Basin and region, experimental field studies on irrigation and agricultural water consumption, current irrigation related policies and strategies in most of the Danube countries, and regulatory frameworks on resources at European Union level. We show that a basin-wide integrative approach to water use calls for the evaluation of resource use trade-offs, resonates with the need for transdisciplinary research in addressing nexus challenges and supports integrative resource management policies within which irrigation water use represents an inherent part. In this respect, we propose a transdisciplinary research framework on sustainable irrigation water use in the Danube Basin. The findings were summarized into four interconnected problem areas in the Danube Basin, which directly or indirectly relate to irrigation strategies and resource policies: prospective water scarcity and Danube water connectedness, agricultural droughts, present and future level of potential yields, and science based proactive decision-making.

Breeding population dynamics of Common Tern Sterna hirundo and associated gull species with overview of conservation management in continental Slovenia

Abstract An overview of the long-term (1980–2019) population development of colonial Laridae species in continental part of Slovenia, their nest sites at anthropogenic water bodies, and various conservation measures with special focus on Common Tern Sterna hirundo along the Slovenian/border part of the Drava River is given. Breeding of these species occurs only on the westernmost fringes of the Pannonian plain, on lowland floodplains of the main rivers of the Danube Basin. Altogether, breeding of Common Tern and Black-headed Gull Larus ridibundus was recorded at 11 and 10 sites, respectively. Lake Ptuj is the single site with mixed-species colony residing there in all years of the study period, while at Ormož (two sites) it was established during the early 1990s in the Slovenian territory but moved completely to the Croatian side by the second half of the 2010s. At all other sites, a suitable breeding habitat became available or was provided by management in just a few years, or created only recently. The percentage of Common Tern national population breeding in continental Slovenia was usually well above 50% throughout the 1980s and 1990s (52–136 pairs), while in the last 16 years (77–258 pairs) it ranged between 40.8% and 69.0%. Breeding of Black-headed Gull remains largely limited to continental Slovenia. Overall, continental populations of both species in the last few years have been substantially higher compared to the most of the study period. Long-term trends were estimated as a moderate increase for Common Tern and a strong increase for Black-headed Gull. Since 2006, the Mediterranean Gull L. melanocephalus has been a regular breeder at Lake Ptuj (up to 28 pairs), the only such site in Slovenia. Three general types of conservation measures implemented at different nesting locations are described in detail: (1) measures to create/increase the total surface of breeding habitat – the construction of new breeding structures, such as artificial islands and nesting rafts, (2) measures to maintain and enhance breeding habitat through recurring management activities, and (3) measures aimed to increase chick/nest survival and improve breeding success.

Danube River Basin Waters on Romanian Territory: Chemical Status Assessment Based on Priority Substances Data Analysis

Framework Directive (2000/60/EC) (WFD) sets out a series of legal measures at European level against surface waters chemical pollution. The EU-list, annex of the WFD, contains those substances that present a significant risk to human health via aquatic environment, known as priority substances. In the last ten years, the Danube water quality has improved significantly. Instead, heavy metals concentrations in the tributaries waters sometimes were found to be rather highest and the chemical status is not in-line with the WFD requirements. Therefore, the Danube River Basin (DRB) waters quality showed a significant variability in terms of priority substances due to the diverse human activities, especially mining activities. This research paper aims to assess the chemical status of the DRB waters located on Romania territory regarding six heavy metals: Pb, Cd, Ni, Cr, Cu, and Zn by analysing water and sediment samples collected from different areas (south-west and north-west of Romania). Based on the obtained results by evaluating the quality elements, the water chemical status of DRB achieved a good chemical status for 74% of water samples and 55% of sediment samples. Also, the basic statistic and multivariate analysis were used to explore the relationship between the concentration values obtained for priority substances to underlying the water quality assessment.

Scale effects on the performance of niche-based models of freshwater fish distributions: Local vs. upstream area influences

Niche-based species distribution models (SDMs) play a central role in studying species response to environmental change. Effective management and conservation plans for freshwater ecosystems require SDMs that accommodate hierarchical catchment ordering and provide clarity on the performance of such models across multiple scales. The scale-dependence components considered here are: (a) environment spatial structure, represented by hierarchical catchment ordering following the Strahler system; (b) analysis grain, that included 1st to 5th order catchments; and (c) response grain, the grain at which species respond most, represented by local and upstream catchment area effects. We used fish occurrence data from the Danube River Basin and various factors representing climate, land cover and anthropogenic pressures. Our results indicate that the choice of response grain – local vs. upstream area effects – and the choice of analysis grain, only marginally influence the performance of SDMs. Upstream effects tend to better predict fish distributions than corresponding local effects for anthropogenic and land cover factors, in particular for species sensitive to pollution. Key predictors and their relative importance are scale and species dependent. Consequently, choosing proper species dependent spatial scales and factors is imperative for effective river rehabilitation measures.

Smart Solutions for Guided Cultural Routes along the Iron Age Archaeological Sites of the Danube Basin

Reverberating on the social expectations connected to the cultural heritage, international cooperation was launched in order to communicate a lively image of archaeological research and to raise awareness for the importance of fragile monumentalized landscapes. The EU funded Iron-Age-Danube project resulted in several working camps, scientific and informative papers, presentations and new museum programmes. A smart device solution offers easy and wide access to the outputs and is the best suited to the present-day experience-oriented tourism approach. The GUIDE@HAND application offers archaeological sites by using a variety of interactive multimedia objects including maps, serious games, augmented reality, videos, panorama pictures, guided tours and a lot of other functions. The content is based on archaeological researches and can be updated even by the non-experts.

Clinoforms as paleogeographic tools: Development of the Danube catchment above the deep Paratethyan basins in Central and Southeast Europe

AbstractThe Miocene marine basins of Central and Southeast Europe, once comprising the Paratethys Sea, were gradually filled with sediments during the Neogene and turned to be the catchment area of the proto‐Danube and finally that of the modern Danube. Seismic data from various parts of the large Danube catchment area show that these several hundred meter deep basins were filled by lateral accretion of river‐transported sediments, appearing as shelf edge scale clinoform sets in seismic profiles. The direction of shelf edge progradation is NW to SE (N to S, W to E) in each basin, except for the Dacian basin where NE to SW direction prevails. The age of the clinoform sets is generally younging downstream: 19–18 Ma in the North Alpine Foreland basin, 14–13 Ma in the Vienna basin, 10–9 Ma in the Danube (Kisalföld) basin, 8.6–4 Ma in the Central Pannonian basin (Alföld), ?9–5 Ma in the Dacian basin, and 6–0 Ma in the Euxinian (Black Sea) basin. In spite of this geographical and temporal pattern, only the Danube (Kisalföld) and the western and central part of the Central Pannonian basin were filled by the proto‐Danube shelf accretion. Formation of the Danube, as a longitudinal river of the Alpine foreland that gradually elongated to the east and followed the retreating shoreline of the Paratethys, most probably took place at the beginning of the Late Miocene, ca. 11 Ma ago, thus the Early and Middle Miocene shelf advance in the North Alpine Foreland and Vienna basins, respectively, cannot be attributed to a „paleo‐Danube”. The clinoform systems of the Dacian basin are coeval with those of the upstream Central Pannonian basin, indicating that by the time the Danube sedimentary system reached the Dacian basin, it was already a shallow basin. The vast clinoforms of the northwestern Euxinian shelf also significantly overlap in age with the Pannonian basin ones; only the &lt;4 Ma part of the shelf accretion can be attributed to the Danube sensu stricto.

Sturgeon re‐introduction in the Upper and Middle Danube River Basin

All six sturgeon species naturally occurring in the Danube River from the Black Sea (BS) to the upstream reaches in Germany today are under severe pressure and classified as either vulnerable, critically endangered or already extinct in the Danube River Basin (DRB). This sharp decline of populations is the result of two major drivers: habitat alteration and unsustainable harvest. The Danube River Basin can be divided in three functionally separated sections by its hydromorphology and character: The Lower Danube (LD) and BS, now also separated ecologically from the Middle Danube (MD) by two hydropower stations at the Iron Gate gorge, 800 km from the sea, currently restricting the remaining anadromous sturgeon species (A. gueldenstaedtii, A. stellatus, Huso huso) to the LD and BS also restraining migrations of potamodromous species. The Upper Danube (UD) is nowadays disconnected from the approx. 850 km long MD by Gabčikovo Dam. The UD itself, as well as many tributaries along the Danube, are fragmented by numerous barriers, leaving no more than a total of 300 km free flowing river out of 700 km. Overharvest led to disappearance of most sturgeon species in the UD already in the Middle Ages, with populations in the MD following in the subsequent centuries. Today the potamodromous sterlet (A. ruthenus) still exists in small decreasing populations in the UD and MD basins, where its occurrence is supported by stocking. Most probably the potamodromous ship sturgeon (A. nudiventris) is extirpated in the whole basin. The Danube basin comprises 19 countries, being the most international river basin in the world, rendering coordinated conservation efforts a challenge. Strategic guidelines for the conservation of the Danube sturgeons are available in form of several action plans, but implementation remains insufficient as of yet. This paper attempts an analysis of the potential for sturgeon restoration in the UD and MD basin and highlights the need for concerted approaches when it comes to ex situ actions and reintroductions.

Production and function of Neolithic black-painted pottery from Schela Cladovei (Iron Gates, Romania)

This paper presents for the first time the results of a combination of petrographic, geochemical and organic residue analyses of early Neolithic ceramics from the Iron Gates region of the Danube basin. Eleven early Neolithic potsherds from Schela Cladovei (Romania) were analysed in detail. The results of the petrographic analysis show that the ceramics were made with the same recipe that was used by Starcevo-Koros-Criș potters elsewhere in southeastern Europe. The SEM-EDX analysis shows one of the earliest uses of Mn-rich black pigments to decorate Neolithic European ceramics. Organic residue analyses detected dairy, non-ruminant and ruminant adipose fats. No evidence of aquatic resources was detected. In summary, the early Neolithic potters at the Iron Gates, although able to make coarse and more sophisticated painted ceramics, did not make specific vessels for a specific use.

Repository of Drought Event Impacts Across the Danube Catchment Countries Between 1981 and 2016 Using Publicly Available Sources

Drought directly and indirectly affects human society in a number of ways. In many regions of the world climate change will exasperate the effects of droughts, affect national economies more intensely. The main aim of this article was to catalogue and analyze the drought impacts in the 11 Central and South Eastern European states located in the Danube river basin. The identification of dry episodes was based on information from publicly available sources, namely, newspaper and journal articles that reported drought impacts. Information on drought impact occurrences was classified into one of five defined categories in which the drought impact report was most clearly manifested (i.e., agriculture, forestry, soil systems, wildfires and hydrology). In terms of the spatial distribution of drought impacts, individual recorded events were analyzed at the level of EU NUTS regions (or their equivalent in non‑EU countries). The analysis highlights country‑specific vulnerability to drought. Furthermore, gradual increases in drought events and the number of reported impacts were identified, which was particularly evident in the agricultural sector.

Significant pedogenic and palaeoenvironmental changes during the early Middle Pleistocene in Central Europe

Three well-developed paleosols from the Paks loess succession (Hungary), a key profile of the European Loess Belt, were sampled and studied by rock magnetic methods, such as low-field magnetic susceptibility and hysteresis measurements. The studied paleosols formed in MIS19, MIS15 and MIS11 and represent key periods in the Middle Pleistocene, namely, the Middle Pleistocene transition (MPT) (MIS19), and frame the mid-Brunhes transition (MIS15 and 11).The results of the low-field magnetic susceptibility measurements, a popular interglacial intensity proxy, showed different patterns and values. The different characteristics of the susceptibility curve indicate different degrees of pedogenesis and therefore different soil-forming palaeoenvironments. The comparison of the rock magnetic (hysteresis) parameters supports the results of the susceptibility measurements and revealed some components of two characteristic palaeoclimate types: i.) a humid and warm MIS19 (pre-)MPT interglacial environment with very intense weathering and pedogenesis and ii.) a moderate climate with seasonal precipitation in a post-MPT interglacial environment during MIS15 and MIS11 characterized by intense but different types of pedogenesis compared to MIS19. This result, compared with other loess successions in the Middle and Lower Danube Basin and the western part of the East European Plain, helps to improve the climate model regarding the changing of the characteristic palaeoenvironment from a sub-Mediterranean (in the south) and temperate and humid climate (with forests, in the north) towards a cooler grassland/forest steppe-ruled environment in the region.