Chemical composition data for the Danube River and its tributaries sediments were analyzed using positive matrix factorization (PMF). The objective was to identify both natural and anthropogenic ...sources affecting Danube Basin. During the Joint Danube Survey 2 (JDS2) campaign 148 bottom sediments samples were collected. The following elements were analyzed using the X-ray fluorescence technique: Al, As, Ca, Cd, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Ti, V and Zn. Mercury was determined by cold vapour atomic absorption spectrometry. Three factors were obtained considering the whole dataset (Danube and tributaries), identified as: (i) carbonate component characterized by Ca and Mg; (ii) alumino-silicate component dominated by Si and Al content and the presence of some metals attributed to natural processes; (iii) anthropogenic source identified by Hg, S, P and some heavy metals load. To better characterize the role of tributaries, the Danube and tributaries datasets, were also analyzed separately. The same three factor structures were identified in the Danube dataset. For the tributaries, a four-factor source model gave one further factor dominated by S and P, which could be attributed to the use of fertilizers in agriculture.
At this time East Asian river prawn
Macrobrachium nipponense
is present almost everywhere in the lower reaches of the Danube and Dniester basins, in the Danube-Dniester interfluves and water bodies ...to the east of the Dniester. Successful adaptation and favorable climatic conditions in recent years have provided a significant increase in the East Asian river prawn populations in the Danube and Dniester. High growth rates of
M. nipponense
have been observed in the Danube and Dniester. In these river basins, higher values of maximum body length of the prawn (males 115 mm, females 87 mm) than those recorded in the native range water bodies and the cooler water bodies of thermal power plants during introduction were recorded. In small shallow brackish-water reservoirs of the region (PSU 1.5–6.0) the growth rate of
M. nipponense
is significantly lower than in the freshwater Danube and Dniester deltaic zones. Female East Asian river prawn in such water bodies mature at a much smaller size. The egg-laying period of female
M. nipponense
in the Danube lasts from June to October. The peak of egg laying is observed in July and August. There have been reported cases of
M. nipponense
being affected by crustacean burn-spot disease. The prospect of organizing the fishing of
M. nipponense
in the Danube River has been determined. It is necessary to continue research to increase selectivity of fishing gears, determination of optimal terms of fishing, and places of installation of fishing gears.
The Lower Danube Basin is one of the most important loess regions from Europe, which have provided excellent archives for long-term high-resolution palaeoclimate studies. The aim of this paper is to ...derive new information on the Middle–Late Pleistocene palaeoenvironment from a high resolution multiproxy assessment of the iron mineralogical composition at the Costineşti loess-palaeosol sequence located on the western Black Sea shore. It is the easternmost loess section in the Romanian loess region studied and its distinct pattern of the proxy records can be used to correlate the lower Danube loess to other key sites of the Moldavia and Ukraine loess regions. To investigate the climatic control on soft and hard ferromagnetic minerals we used several types of rock magnetic properties: magnetic susceptibility and its frequency dependence, anhysteretic remanent magnetization, isothermal remanent magnetization, hysteresis properties and FORC distributions, an unmixing model for isothermal remanent magnetization curves and high field (up to 8 T) isothermal remanence measurements. Our results show that the palaeosol horizons, formed during interglacials and climatically more favored periods of the Pleistocene, experienced pedogenic alteration, resulting in high amounts of superparamagnetic, single domain and pseudosingle domain magnetite/maghemite grains and hematite. The loess layers, formed during glacial periods, are mainly dominated by multidomain and/or pseudosingle domain oxidized magnetite and some hematite, all probably of aeolian origin. Goethite contribution is probably minor and constant both in loess and palaeosol horizons. We review the correlation of the loess sections from the lower Danube basin concluding that the new results can be interpreted as a support for the transition of a Mediterranean type climate to a steppe type climate in the last two interglacial periods in the western Black Sea. Because the pattern of magnetic susceptibility data from the lower Danube basin is changing relative fast with distance from the Black Sea shore, it probably reflects the local influence of the Black Sea on continental scale climatic oscillations during the last 600 ka. The values of background magnetic susceptibility of the Romanian loess-palaeosol sections indicate that the main source area of the dust changed during this climatic transition. Our analysis also shows that the age of the loess-palaeosol sections from the Eastern European low lands (Moldavia and Ukraine) must be revised to be in agreement with the chronostratigraphy of the sections from the Lower Danube Basin loess area.
As the Intergovernmental Panel on Climate Change reported in 2013, climate change will have significant impacts on all water sectors. Since water is essential for live, culture, economy and ...ecosystems, climate change adaptation is crucial. Therefore, a legal and political framework was established by the commissions of the European Union, the United Nations and on national levels. For the Danube River Basin (DRB), the International Commission for the Protection of the Danube River got the mandate to develop an adaptation strategy in 2012 and to update this strategy in 2018. The natural science basis on which the adaptation strategy and its update are based on are two studies, conducted in 2011/2012 and updated and revised in 2017/18. Numerous documents from actual research and development projects and studies dealing with climate change and its impacts on water related issues were analysed in detail and the results summarised. It is agreed that temperature will increase basin-wide. The precipitation trend shows a strong northwest-southeast gradient and significant changes in seasonality. Runoff patterns will change and extreme weather events will intensify. However, the magnitude of the results shows a strong spatial variability due to the heterogeneity of the DRB., It is assessed that these changes will have mostly negative impacts on all water related sectors. Based on the scientific findings an approach for an improved basin-wide strategy on adaptation to climate change is developed. It includes guiding principles and five categories of adaptation measures targeting different objectives.
In 2016, an intense copepod infection was recorded from a reservoir in proximity to the Danube River in Hungary from visibly emaciated wels catfish, Silurus glanis. The parasite-induced pathology was ...described but parasite identity was not conclusive. Additional sample collections in 2017 and 2018 allowed for identification using both light and scanning electron microscopy, alongside genetic characterisation. The copepods were confirmed to be ergasilids, Sinergasilus major, distinctly different from any previous infection on silurids in Europe. This is the first record of this parasite from Hungary and the first host record from wels catfish.
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•First record of Sinergasilus major from wels catfish (Silurus glanis).•First record of S. major from Hungary.•Light and scanning eletron microscopy support identification of S. major.•100% similarity of the 18S rDNA provides significant confidence to the identification of the copepods as S. major.
The Danube River Basin is the second longest catchment basin in Europe and exhibits intense climatological diversity. In recent decades, the frequency and intensity of daily precipitation extremes ...have suffered from an increment in many parts of the world, including Central and Eastern Europe. Wet spells are defined by the number of consecutive rainy days with different thresholds. The identification of wet spells and their trends in the rainfall time is very important for many sectors, such as agriculture, ecology, hydrology and water resources. Wet spells can lead to extreme events and cause floods and other disasters. In this study, we will attempt to characterise global precipitation in the context of wet spells and associated precipitation depth of wet spells in the Danube River Basin area using daily precipitation data, as well as analysing different approaches to identifying wet spells. The ten most intense wet spells were detected, and the most intense, which occurred on 23 September 1996, was studied in depth in terms of precipitation and associated anomalies, the synoptic situation and the anomalous transport of moisture using a Lagrangian approach. The existence of a marked west-east dipole in the field of sea level pressure between the Atlantic Ocean and the eastern Mediterranean leads to the anomalous moisture transport from the Northern Atlantic Ocean to the Mediterranean Sea, where a higher available amount of moisture existed, and subsequently penetrated within the low positioned over the Danube River Basin. In addition, an Atmospheric River was also responsible for the wet conditions in the Danube River Basin. The combination of all these factors was responsible for the extreme precipitation linked with the wet spell.
Climate change is presently a widely discussed subject in relation to alterations in water storage capacity and the components of the hydrological balance within catchment areas. This research study ...was directed at two main objectives: 1. The indirect estimation of long-term mean annual runoff using an empirical model; 2. The determination of changes in the annual runoff regime of fifty Danube sub-basins. Monthly areal precipitation, discharges, and air temperature data from 1961 to 1990 were collected for selected headwater sub-basins of the Danube River. In the first part, Turc-type empirical equations for the estimation of the long-term average annual runoff
in the Danube basin were employed. The parameters of the empirical equations were determined through nonlinear regression. Given the underestimation of the actual (territorial, balance) evapotranspiration
values determined from the balance equation, the precipitation totals were corrected by +10%. With a 10% increase in precipitation, the values of balance
reached the values
determined by the Budyko–Zubenok–Konstantinov method. In the second part, fifty equations for the estimation of changes in the average annual runoff, depending on increases in the air temperature and changes in the annual precipitation separately for each of the 50 sub-basins, were established. In conclusion, the results suggest that, on average, a 100 mm increase in the average annual rainfall in the Danube River headwater sub-basins, will cause a 50 mm increase in outflow, and a 1 °C increase in the average annual air temperature will lead to a 12 mm decrease in runoff.
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