Diversity of Molluscs in the Danube river (1269-863.5 rkm) and taxonomic analysis of the genera Planorbarius, Radix, Physella and Ferrissia (Pulmonata: Basommatophora)

Analiza slatkovodnih mekušaca razmatrana je kroz tri zone glavnog toka Dunava (1260 - 863,5 rkm) kao i plavnoj zoni, na levoj obali reke, od 1082 do 1085 rkm. Uzorci su prikupljeni sezonski (april, jun, septembar i novembar), u tri ponavljanja, uključujući uzorke za analizu fizičkih i hemijskih parametara kvaliteta vode i sedimenta. Ovim istraţivanjima dat je detaljan pregled sastava i distribucije malakofaune istraţivanog dela rečnog toka pri različitim uticajima grupe antropogenih pritisaka. Primenom molekularnih metoda razmatrani su filogenetski odnosi autohtonih i alohtonih vrsta iz reda Basommatophora. Analizom zajednica akvatičnih makroinvertebrata, uočeno je da plavnu zonu reke karakteriše najveća procentualna zastupljenost insekatskih grupa (61,69%) kao i fitofilnih vrsta slatkovodnih mekušaca (15%). Lokalitete rečne, prelazne i jezerske zone karakteriše velika procentualna zastupljenost pre svega Oligochaeta (37,89%, 63,83%, 83,99%), zatim Bivalvia (38,21%, 24,35%, 16,72%) i Crustacea (15,82%, 31,11%, 13,73%), što predstavlja karakteristične odnose u zajednicama makroinvertebrata reka potamon tipa. Analizom zajednica slatkovodnih mekušaca zabeleţeno je 32 taksona iz 28 rodova i 13 familija u okviru dve klase - Bivalvia i Gastropoda. Klasa Bivalvia zastupljena je sa 12 taksona iz četiri familije u okviru redova Veneroida i Unionida. Najveći procenat, 92% od ukupnog broja zabeleţenih taksona iz klase Bivalvia, zabeleţen je na lokalitetima prelazne zone; nešto manji procenat od 75% zabeleţen je u jezerskoj zoni; dok je najmanja zastupljenost zabeleţenih taskona uočena na lokalitetima rečne zone (41%). Klasa Gastropoda zastupljena je sa 20 taksona, iz dve potklase, Prosobranchia (Orthogastropoda) i Pulmonata. Posmatrajući raznovrsnost taksona iz klase Gastropoda na istraţivanim lokalitetima, najmanji broj taksona uočen je u gornjem delu toka Dunava (20%), dok je najveća raznovrsnost zabeleţena u plavnoj zoni gde je naĎeno 55% od ukupnog broja zabeleţenih taksona...Fresh water molluscs analysis was performed through three zones of The Danube main flow (1260-863.5 rkm) as well as flooding zone, on the left river bank from 1080 to 1085 rkm. Samples were collected seasonally (April, June, September and November), in three repetitions, along with samples for physical and chemical analysis of water and sediment quality. This research presents detailed summary of composition and distribution of malacofauna in analysed part of the river flow under different influence of anthropogenic pressure. Molecular methods were used for establishing phylogenetic relationships among native and alien species from Basommatophora order. Analysis of aquatic macroinvertebrate communities showed that river flooding zone is characterized by highest percentage of occurrence for insect groups (61.69%) as well as phytophilic species of freshwater molluscs (15%). Localities from riverine, transitional and lacustrine zone are characterized by large percentage of occurrence of Oligochaeta (37.89%, 63.83%, 83.99%), then Bivalvia (38.21%, 24.35%, 16.72%) and Crustacea (15.82%, 31.11%, 13.73%), which is characteristic for macroinvertebrate communities of potamon river type. Analysis of aquatic molluscs communities showed that 32 taxa from 28 genera and 13 families within two classes Bivalvia and Gastropoda were recorded. Class Bivalvia is represented with 12 taxa from four families within orders Veneroida and Unionida. Highest percentage, 92% from total number of all recorded taxa within class Bivalvia, was found in localities in transitional zone, about 75% in lacustrine zone; lowest percentage of identified taxa was recorded at riverine zone localities (41%). Classis Gastropoda is represented with 20 taxa from two subclasses, Prosobranchia (Orthogastropoda) and Pulmonata..

The uniqueness of the beryllium-7 time series in Kista and Vienna over 1987–2014

Activity concentration of beryllium-7 (Be-7) in the surface air is considered a good tracer of atmospheric processes. Promptly after its production, this radionuclide attaches to aerosols and then subsides to the surface where its concentrations depend on the aerosol removal processes, e.g. precipitation, and atmospheric transport drivers, e.g. temperature and pressure. Our study investigates whether a set of five variables: mean temperature, minimum temperature, maximum temperature, precipitation and atmospheric pressure can account for the Be-7 concentration variability at the surface. We use the Be-7 activity concentration from the Radioactivity Environmental Monitoring data bank maintained by the Joint Research Centre in Ispra, Italy. We look into two locations, Kista (59.40 °N; 17.93 °E; 16 m a.s.l.) in Sweden and Vienna (48.22 °N; 16.35 °E; 193 m a.s.l.) in Austria, between February 1987 and December 2014, when the sampling was performed on a weekly basis. The meteorological parameters are extracted from the E-OBS gridded climatology, version 15, using bilinear interpolation. For each location, we perform Factor Analysis. The calculations are done in R, an open-source software for statistical computing and graphics. Factor Analysis assumes that a given set can be modelled as a linear combination of unobserved uncorrelated factors. Loadings are contributions of each original variable to a factor; variables with high loadings are well explained by the factor. The total data variability has two terms: communality arising from the linear combinations of the factors, and uniqueness not explained by the factors. The model is appropriate if the uniqueness is low. The null hypothesis in Factor Analysis is that the chosen number of factors is sufficient to explain the variability of the data; the hypothesis is rejected if the calculated p-value is less than 0.05. We perform Factor Analysis by choosing 1, 2 and 3 factors. Results for both locations give similar results. One factor (F1): Temperatures show very high loadings (greater than 0.98) making F1 identical to a temperature variable in the set. The loading of the Be-7 concentration is 0.39 and 0.68 for Kista and Vienna, respectively. The loadings of precipitation and atmospheric pressure are less than 0.4. With the low Be-7 concentration loading, its uniqueness is large, giving temperature, as a single contributing factor, insufficient to explain well the data’s features. This is corroborated by the p-value=0. Two factors (F1 and F2): The sum of square loadings for F1 is greater than 3 making it significant, unlike F2 (a factor is significant if the sum of square loadings is greater than 1). The Be-7 concentration and temperatures have high loadings for F1, but precipitation has a negligible F1-loading; precipitation has a significant loading for F2, while the pressure has similar loadings for F1 and F2. Although the uniqueness of the Be-7 concentration decreases with two factors, p-value is again very low, essentially zero. Three factors (F1, F2 and F3): Again, F1 with the highest temperature loadings can be identified as a temperature variable. The loading of atmospheric pressure is the highest for F2. Both F1 and F2 are significant, while F3 is insignificant. Also, we cannot assess the validity of the null hypothesis regarding the use of the 3-factor model, because this model has zero degrees of freedom, thus no p-value can be calculated. Nevertheless, if we look into the uniqueness of the Be-7 concentration, its lowest values are given by this model. In conclusion, all variables exhibit a variance that cannot be captured by up to 3 factors. Still, the Be-7 concentration seems to be strongly correlated with the temperature variables in all the investigated models. But, the uniqueness of the Be-7 concentration remains high, implying that the chosen set of variables lacks an important observable that could help explain the behaviour of the Be-7 concentration at the surface.Book of Abstract

ISOLATION OF MICROPLASTICS FROM FRESHWATER MACROINVERTEBRATES IN THE DANUBE RIVER

The study was conducted on the Danube River, within the project Joint Danube Survey 3 (JDS3). The main aim was to estimate the quantity of microplastics in aquatic ecosystems through passive biological monitoring. Three freshwater species were used for microplastic (MP) isolation from different taxonomic groups of organisms: Mollusca, Oligochaeta, and Chironomidae (Diptera), with the following species: Lithoglyphus naticoides (C. Pfeiffer, 1828), Limnodrilus hoffmeisteri (Claparede, 1862), and Chironomus acutiventris (Wülker, Ryser & Scholl, 1983), respectively. The samples were collected from 6 sites along the Danube River where 540 specimens were examined. The samples were digested by alkaline method (incubation in 10% KOH solution at 60 ⁰C for 24 h) and filtered through a mill silk, 10 µm mesh size. Collected particles were categorized as: fibre, hard plastic, nylon, rubber, or miscellaneous. Categories were divided into subcategories based on the coloration of the particles. Particles ingested by organisms were represented mostly by fibres and fragmented hard plastics, within the size range were from 0.03 to 4.87 mm. A total of 678 MP particles were collected with an average of 4.64 ± 1.59; 1.64 ± 0.46 and 1.24 ± 0.34 items/organism isolated from L. hoffmeisteri, L. naticoides and C. acutiventris, respectively. According to results, L. hoffmeisteri, L. naticoides and C. acutiventris could be used as proper bioaccumulators of MP pollution in the Danube River

First report on the non-indigenous triclad girardia tigrina (Girard, 1850) (Tricladida, Dugesiidae) in Serbia, with Notes on its Ecology and Distribution

Girardia tigrina (Girard, 1850) (Turbellaria, Tricladida, Dugesiidae), a native freshwater triclad of North America, is a widespread species, which has been introduced by human activities into various parts of the world, including Europe. The aim of this paper is to contribute to the knowledge of this species by presenting its frst record and recent distribution in Serbia. Girardia tigrina was recorded in Serbia in 2008 in the lower stretch of the Kolubara River. After this initial fnding, the species was identifed only a few more times, but with low abundance. Its presence only in the northern part of Serbia, in the Danube River and in its proximity, points to the Danube River and its larger tributaries (the South invasive corridor) as the main route of its spread in the country. Our data suggest that G. tigrina should not be considered an invasive species but as an alien species with a minor impact on native communities

Comparison of the effectiveness of kick and sweep hand net and Surber net sampling techniques used for collecting aquatic macroinvertebrate samples

The objective of this work is to analyze the effectiveness of two widely used methods for collecting aquatic macroinvertebrate samples: the semiquantitative kick and sweep (K&S) and quantitative Surber net (SN) techniques. Based on our data, the methods were fully comparable as regards analysis of the macroinvertebrate metrics most often used in ecological status assessment (sensitivity/tolerance parameters), while K&S was found to be more successful in the evaluation of biodiversity. Thus, both methods could be used for routine monitoring of the status of water bodies, according to the recommendation of the EU Water Framework Directive, while for research, K&S is more advanced. K&S is also more effective timewise for material collecting. SN sampling is a quantitative method and could thus be used in studies of aquatic ecosystem productivity.Archives of Biological Sciences (2017), 69(2): 233-23

First limnological investigations of the water quality of the Lake Srebrno in Serbia

The first limnological investigations of the Lake Srebrno water quality were performed in March 2007. The investigations included qualitative, quantitative, and saprobiological analyses of bottom fauna communities, physical chemical analyses of sediments and the determination of chlorophyll a concentration, as well as analyses of the trophic status. Samples were collected at eighteen localities distributed along the shore line, as well as from the deep parts of the lake. Twenty taxa from nine macro-invertebrate groups were recorded. The classification of the water in Lake Srebrno was proposed, based on trophic and saprobic levels. Trophic levels were in the range of upper limits of meso- to eutrophy, and within the limits of the eutrophic status. Calculated values of the Saprobic Index S, based on bio-indicator organisms of macrozoobenthos, ranged from S=2.81 to S=3.58. The water quality was estimated to be within the limits proposed to III and IV-III class of the Serbian (Yugoslav) watercourses.Tokom marta 2007. godine obavljena su prva istraživanja kvaliteta vode Srebrnog jezera u Srbiji. Ispitivanja su obuhvatila kvalitativnu, kvantitativnu i saprobiološku analizu zajednica makrozoobentosa, fizičko-hemijsku analizu sedimenata i određivanje koncentracije hlorofila, a kao i analizu trofičnog statusa. Uzorci su sakupljeni sa osamnaest lokaliteta, raspoređenih duž obale u litoralu i iz dubljih zona jezera. U okviru faune dna, zabeleženo je devet faunističkih grupa sa ukupno dvadeset taksona. Procenjivan je kvalitet vode Srebrnog jezera sa stanovišta trofije i saprobnosti. Stupanj trofije Srebrnog jezera je u oblasti gornje granice mezo- na prelazu u eutrofiju i u granicama eutrofnog statusa. Izračunate vrednosti saprobnog indeksa S po metodi Pantle-Bucka, primenom saprobnog sistema bioindikatorskih vrsta makrozoobentosa, bile su u opsegu od S=2,81 do S=3,60. Procenjeni kvalitet vode bio je u granicama III i na prelazu IV-III klasu.nul

Comparison of the effectiveness of kick and sweep hand net and surber net sampling techniques used for collecting aquatic macroinvertebrate samples

The objective of this work is to analyze the effectiveness of two widely used methods for collecting aquatic macroinvertebrate samples: the semiquantitative kick and sweep (K&S) and quantitative Surber net (SN) techniques. Based on our data, the methods were fully comparable as regards analysis of the macroinvertebrate metrics most often used in ecological status assessment (sensitivity/tolerance parameters), while K&S was found to be more successful in the evaluation of biodiversity. Thus, both methods could be used for routine monitoring of the status of water bodies, according to the recommendation of the EU Water Framework Directive, while for research, K&S is more advanced. K&S is also more effective timewise for material collecting. SN sampling is a quantitative method and could thus be used in studies of aquatic ecosystem productivity.The final publication is available at [http://www.serbiosoc.org.rs/arch/index.php/abs/article/view/731]Archives of Biological Sciences (2016), OnLine Firs

First limnological investigations of the water quality of the Lake Srebrno in Serbia

The first limnological investigations of the Lake Srebrno water quality were performed in March 2007. The investigations included qualitative, quantitative, and saprobiological analyses of bottom fauna communities, physical chemical analyses of sediments and the determination of chlorophyll a concentration, as well as analyses of the trophic status. Samples were collected at eighteen localities distributed along the shore line, as well as from the deep parts of the lake. Twenty taxa from nine macro-invertebrate groups were recorded. The classification of the water in Lake Srebrno was proposed, based on trophic and saprobic levels. Trophic levels were in the range of upper limits of meso- to eutrophy, and within the limits of the eutrophic status. Calculated values of the Saprobic Index S, based on bio-indicator organisms of macrozoobenthos, ranged from S=2.81 to S=3.58. The water quality was estimated to be within the limits proposed to III and IV-III class of the Serbian (Yugoslav) watercourses.Tokom marta 2007. godine obavljena su prva istraživanja kvaliteta vode Srebrnog jezera u Srbiji. Ispitivanja su obuhvatila kvalitativnu, kvantitativnu i saprobiološku analizu zajednica makrozoobentosa, fizičko-hemijsku analizu sedimenata i određivanje koncentracije hlorofila, a kao i analizu trofičnog statusa. Uzorci su sakupljeni sa osamnaest lokaliteta, raspoređenih duž obale u litoralu i iz dubljih zona jezera. U okviru faune dna, zabeleženo je devet faunističkih grupa sa ukupno dvadeset taksona. Procenjivan je kvalitet vode Srebrnog jezera sa stanovišta trofije i saprobnosti. Stupanj trofije Srebrnog jezera je u oblasti gornje granice mezo- na prelazu u eutrofiju i u granicama eutrofnog statusa. Izračunate vrednosti saprobnog indeksa S po metodi Pantle-Bucka, primenom saprobnog sistema bioindikatorskih vrsta makrozoobentosa, bile su u opsegu od S=2,81 do S=3,60. Procenjeni kvalitet vode bio je u granicama III i na prelazu IV-III klasu.nul

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

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

Faunistic patterns and diversity components of leech assemblages in karst springs of Montenegro

The aim of this study was to reveal faunistic and diversity patterns and to assess the effects of environmental factors on the differentiation of leech communities. This study covers investigations of 82 karst springs in Montenegro from 2009–2017. The communities were analyzed in respect to five wellspring types – caves, sublacustrine, limnocrene, rheo-limnocrene and rheocrene. The percentage of substrate types and aquatic vegetation cover was recorded alongside water parameters. In total, 18 leech species were identified, of which two were recently described as new species for science (Dina minuoculata Grosser, Moritz and Pešić, 2007 and Glossiphonia balcanica Grosser and Pešić, 2016). K-means clustering was used to classify leech assemblages into three homogenous groups. The patterns of leech communities and the components of both alpha and beta diversity were examined in identified groups of assemblages. The significance of environmental factors and the impact of selected factors were assessed through forward selection analysis, CCA and RDA. Our results indicate that the type of spring and the environmental variables, as well as the combination of biotic and abiotic factors in a microhabitat dictate the distribution of leeches