scholarly journals Contribution to the knowledge on the distribution of freshwater sponges – the Danube and Sava rivers case study

2017 ◽  
Vol 77 (2) ◽  
Author(s):  
Stefan Andjus ◽  
Nadja Nikolic ◽  
Valerija Dobricic ◽  
Ana Marjanovic ◽  
Zoran Gacic ◽  
...  
Keyword(s):  
Danube River ◽  
Sequencing Analysis ◽  
Freshwater Sponges ◽  
The Danube River ◽  
Rdna Sequencing ◽  
Freshwater Invertebrate ◽  
Sava River ◽  
Ephydatia Fluviatilis ◽  
The Sava River

Sponges in the large rivers within the Danube River Basin (DRB) have not been adequately studied. Hence, the aim of this work was to undertake an investigation on the distribution of sponge species in the Danube and Sava rivers. Out of 88 localities covered by the study, sponges were found at 25 sites only (46 samples in total). By using morphological (light and scanning electron microscopy) and genetic (28S rDNA sequencing) analysis, four species were determined: Ephydatia fluviatilis (Linnaeus, 1759), Spongilla lacustris (Linnaeus, 1759), Eunapius fragilis (Leidy, 1851), Trochospongilla horrida Weltner, 1893. In the Danube, the predominant species was found to be E. fluviatilis making approximately 80% of collected samples, while in the Sava River S. lacustris dominated, representing 46% of the river sponges. Our work represents one of the few studies on freshwater sponges within the DRB from long stretches of the large lowland rivers (more than 2500 km of the Danube River and about 900 km of the Sava River). Moreover, molecular analysis for the identification of freshwater sponges was applied on the material collected from a wide area, thus contributing to the systematic studies on the distribution and abundance of the European freshwater invertebrate fauna in general.

Distribution of H and O stable isotopes in the surface waters of the Sava River, the major tributary of the Danube River

2018 ◽  
Vol 565 ◽  
pp. 365-373 ◽  
Author(s):  
Nives Ogrinc ◽  
David Kocman ◽  
Nada Miljević ◽  
Polona Vreča ◽  
Janja Vrzel ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Surface Waters ◽  
Danube River ◽  
The Danube River ◽  
Sava River ◽  
Major Tributary ◽  
The Sava River

Investigation of correlations between magnetic susceptibility and elemental content in the Kupa River sediments (Croatia)

2020 ◽  
Author(s):  
Stanislav Frančišković-Bilinski ◽  
Sanja Sakan ◽  
Dragana Đorđević ◽  
Aleksandar Popović ◽  
Sandra Škrivanj ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Negative Correlation ◽  
River Sediments ◽  
Danube River ◽  
Residual Fraction ◽  
Elemental Content ◽  
Icp Oes ◽  
The Danube River ◽  
Sava River ◽  
The Sava River

<p>The Kupa River basin occupies the west-central part of Croatia and is shared by two neighboring countries (Slovenia, Bosnia and Herzegovina). It is the tributary of the Sava River and meets the latter at Sisak after traversing a distance of 294 km. The Sava River belongs to the Danube River watershed and enters the Danube River at Belgrade (Serbia).      </p><p>An extreme barium anomaly in sediments of Kupica and Kupa rivers was discovered during 2003 (Frančišković-Bilinski, 2006). It is result of un-careful mine waste disposal. Therefore this river has a big potential to be used as a “natural laboratory” in the future to study sediment transport processes in rivers, so we repeated sampling on most important locations in 2018, to see which processes happened during that time frame. In the current study, we aim to investigate correlations between magnetic susceptibility (MS) and elemental content of 26 studied elements in the fine sediment fraction (<63 µm) of samples from 2018. MS method is a fast and cheap method, which can give indication of contamination with some metals, so we aimed to test its suitability on Kupa River sediments. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used to determine the concentration of the studied elements, after sequential extraction procedure (Sakan et al., 2016). Total concentrations of each element were determined as the sum of concentrations determined in each fraction. The same method was applied recently for determination of Ba concentrations in Kupa River sediments by Frančišković-Bilinski et al. (2019).</p><p>Correlation analysis was performed to reveal statistical correlations between MS and 26 elements analyzed by ICP-OES. Ten of them showed negative correlation (As, B, Ba, Fe, K, Li, Mg, Na, P, S), while other elements showed positive. Chromium showed excellent correlation with MS (0.91) and is element with the highest correlation to MS. All other elements show much weaker correlation with MS. Element with strongest correlation to MS after Cr is vanadium (0.62), followed by Mn (0.52), Al (0.52) and Cd (0.50). All other elements have rather weak correlation with MS, among which highest are those of Sr (0.45), Zn (0.35), Be (0.28), Co (0.27), Pb (0.27) and Ti (0.26). Rest of elements has very low correlation.</p><p>Our research confirmed that MS is not suitable to study barium contamination in sediments, as they have low negative correlation (-0.18). Low negative correlation of MS with Fe (-0.12) indicates that MS is not caused by iron minerals in Kupa River sediments. MS values show extreme value at the same location as does Cr, which is bound to residual fraction of yet not known mineral composition.</p><p>Earlier data of Frančišković-Bilinski (2007) show that SiO<sub>2 </sub>group of minerals predominate in Kupa sediment at Pokupsko, where MS and Cr have highest values.</p><p>Rererences:</p><p>Frančišković-Bilinski, S. (2006). J.Geochem.Explor. 88, 1-3, 106-109.</p><p>Frančišković-Bilinski, S. (2007). Fresenius Env.Bull. 16, 5, 561-575.</p><p>Frančišković-Bilinski S., Bilinski, H., Sakan, S., Đorđević, D., Popović, A. (2019). SGEM Conference proceedings, 19, 3.1., 73-80.</p><p>Sakan, S., Popović, A., Anđelković, I., Ðorđević, D. (2016). Env.Geochem.Health 38, 855–867.</p>

scholarly journals The co-existence of recreational and artisanal fisheries in the central parts of the Danube and Sava rivers

2017 ◽  
Vol 75 (4) ◽  
pp. 89-94
Author(s):  
Tomislav Treer ◽  
István Kubatov
Keyword(s):  
Bosnia And Herzegovina ◽  
Danube River ◽  
Artisanal Fisheries ◽  
Recreational Fisheries ◽  
The Danube River ◽  
Sava River ◽  
Official Data ◽  
The Sava River

Abstract The official data on recreational and artisanal fisheries in Croatia and Hungary were analysed. The data from Croatia relates to the entire Croatian section of the Danube River and to the section of the Sava River along the border with Bosnia and Herzegovina. The data from Hungary covers 60 km of the Danube River north of the Croatian border. Absolute catches in kilograms, as well as CPUE (kg per fisherman per year) by both groups in all three river sections varied from year to year without dramatic changes. Fishing with nets, artisanal fishermen differ from the anglers in two major ways: they are less selective and they catch bigger specimens. According to the official data, the existing ratio between recreational and artisanal fishermen in these three river sections does not negatively affect each other’s or overall fishing. Therefore, a conclusion can be drawn that medium-intensive artisanal fisheries qualify to co-exist with recreational fisheries.

scholarly journals Hydrological simulation of flood transformations in the upper Danube River: Case study of large flood events

2016 ◽  
Vol 64 (4) ◽  
pp. 337-348 ◽  
Author(s):  
Veronika Bačová Mitková ◽  
Pavla Pekárová ◽  
Pavol Miklánek ◽  
Ján Pekár
Keyword(s):  
Natural Transformation ◽  
Danube River ◽  
Human Society ◽  
Hydrological Simulation ◽  
The Danube River ◽  
Natural Processes ◽  
The Past ◽  
River Reach ◽  
Flood Waves

Abstract The problem of understand natural processes as factors that restrict, limit or even jeopardize the interests of human society is currently of great concern. The natural transformation of flood waves is increasingly affected and disturbed by artificial interventions in river basins. The Danube River basin is an area of high economic and water management importance. Channel training can result in changes in the transformation of flood waves and different hydrographic shapes of flood waves compared with the past. The estimation and evolution of the transformation of historical flood waves under recent river conditions is only possible by model simulations. For this purpose a nonlinear reservoir cascade model was constructed. The NLN-Danube nonlinear reservoir river model was used to simulate the transformation of flood waves in four sections of the Danube River from Kienstock (Austria) to Štúrovo (Slovakia) under relatively recent river reach conditions. The model was individually calibrated for two extreme events in August 2002 and June 2013. Some floods that occurred on the Danube during the period of 1991–2002 were used for the validation of the model. The model was used to identify changes in the transformational properties of the Danube channel in the selected river reach for some historical summer floods (1899, 1954 1965 and 1975). Finally, a simulation of flood wave propagation of the most destructive Danube flood of the last millennium (August 1501) is discussed.

scholarly journals The Assessment of the Surface Water Quality Using the Water Pollution Index: A Case Study of the Timok River (The Danube River Basin), Serbia

2012 ◽  
Vol 38 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Jovana Brankov ◽  
Dragana Milijašević ◽  
Ana Milanović
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Oxygen Demand ◽  
Pollution Index ◽  
Surface Water Quality ◽  
Danube River ◽  
Water Pollution Index ◽  
The Danube River ◽  
The Republic

The Assessment of the Surface Water Quality Using the Water Pollution Index: A Case Study of the Timok River (The Danube River Basin), Serbia The Timok River (202 km long, 4547 km2 basin area) is located in East Serbia. It is a right tributary of the Danube River and one of the most polluted watercourses in Serbia. On the basis of the data provided by the Republic Hydrometeorological Service of Serbia, the paper presents an analysis of water quality and pollution using the combined physico-chemical WPI index (Water Pollution Index) calculated for two periods - 1993-96 and 2006-2009 at four hydrological stations: Zaječar-Gamzigrad (Crni Timok River), Zaječar (Beli Timok River), Rgotina (Borska Reka River) and Čokonjar (Timok River). The following parameters were taken into consideration: dissolved O2, O2 saturation, pH, suspended sediments, Five Day Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (CODMn), nitrites, nitrates, orthophosphates, ammonium, metals (Cu, Fe, Mn, Hg, Ni, Zn, Cd), sulphates and coliform germs. The average WPI values were calculated for the observed periods based on the comparison of the annual average values of the listed parameters and defined standard values for the I water quality class (according to the Regulation on the Hygienic Acceptability of Potable Water of the Republic of Serbia). The highest pollution degree was recorded in the Borska Reka River, where heavy metal levels (especially manganese and iron) were significantly increased. These metals are indicators of inorganic pollution (primarily caused by copper mining). Also, increased values of the organic pollution indicators (ammonium, coliform germs, Five-Day Biological Oxygen Demand - BOD5) in the Borska Reka and the Timok rivers are the result of uncontrolled domestic wastewater discharge.

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