Danube Delta National Institute
Danube Delta National Institute
Kohlmann K.,Leibniz Institute of Freshwater Ecology and Inland Fisheries |
Kersten P.,Leibniz Institute of Freshwater Ecology and Inland Fisheries |
Gessner J.,Leibniz Institute of Freshwater Ecology and Inland Fisheries |
Onara D.,Danube Delta National Institute |
And 2 more authors.
European Journal of Wildlife Research | Year: 2017
The stellate sturgeon, Acipenser stellatus, is a critically endangered fish species. Knowledge on its genetic diversity and population structure is urgently needed to enable the identification of management units in order to prevent extinction. Therefore, 18 species-specific, polymorphic microsatellite loci have been isolated using GS-FLX Titanium pyrosequencing, arranged into 6 multiplex PCR sets, and characterized in 52 individuals (20 farmed and 32 wild). The total number of alleles per locus varied between 3 and 36 with an average of 8.44. The wild individuals were more diverse with an average number of 8.17 alleles per locus than the farmed ones with 3.28 alleles per locus. Observed heterozygosities ranged from 0.050 to 0.950 in the farmed and from 0.094 to 0.969 in the wild individuals. Significant deviations from Hardy-Weinberg equilibrium were found at 3 loci of the farmed and 5 loci of the wild individuals. The two sturgeon groups were significantly differentiated (FST = 0.118). The high sensitivity and discriminatory power of the 18 loci were proven by a very low overall probability of identity for siblings (PIsib = 8.73 × 10−6) and a high accuracy of self-classification (98%). Thus, these newly developed markers represent a valuable genetic toolbox to identify management units for species conservation and sustainable fisheries. © 2017, Springer-Verlag GmbH Germany.
Vespremeanu-Stroe A.,University of Bucharest |
Zainescu F.,University of Bucharest |
Preoteasa L.,University of Bucharest |
Tatui F.,University of Bucharest |
And 8 more authors.
Marine Geology | Year: 2017
The Danube delta is one of the few large deltas in the world the evolution of which has involved numerous and varied episodes within a complex framework of interactivity between river sediment supply, allochthonous sediments supplied by longshore currents, marine dispersing forces, vertical movements (neotectonics, sediment compaction) and sea level. The resulting complex morphology comprises diversified landscapes varying from labyrinthic net of channels and lakes (fluvial delta) to massive tracts of monotonous reed marshes, large lagoons divided by barriers, or beach-ridge plains accommodating large transgressive dunefields (maritime delta). Whilst previous studies have focused on various sectors of the Danube delta, the current paper proposes for the first time an integral reconstruction of delta evolution based on existing and new sedimentological and morphological analyses and absolute ages (AMS 14C and OSL), enabling a comprehensive synthesis in terms of both evolutionary phases and growth patterns. A chronological framework was established for all the deltaic lobes and beach-ridge plains, highlighting the relationship between formation timespan, growth rates, and the resultant morphology. This work unveils the early stage of delta formation, including the reconstruction of delta front advancement into Danube Bay (Old Danube lobe: prior to 7.5–5.5 ka) and initial spit/barrier development (6.7/6.5–5.8 ka). Inception of the bayhead delta started > 1000 yr before the relative stabilization of sea level and of the initial spit formation. The original fluvial delta plain topography is now buried at a depth of 4–6 m depth below the present topography (representing the current stage of fluvial aggradation), as a result of subsidence and sea-level rise. Regarding the maritime delta, six large open-coast lobes developed in the last six millennia, of which four were formed by the Sf. Gheorghe branch, attesting the long uninterrupted activity of this branch, whereas the other two were created respectively by the Sulina and the Chilia branches. The evolution of each lobe is derived from successive (chronological) shoreline positions and discussed in relation with changes in Danube discharge. Special attention has been paid to their growth stages and progradation rates. For the southern delta, we bring in new arguments for an active southern distributary (the Dunavăţ, derived from the Sf. Gheorghe branch) that formed successive open-coast lobes between 2.6 and 1.3 ka. Additionally, we discuss the effects of modern anthropogenically-driven fluvial sediment reduction on the morphology and morphodynamics of the active lobes of the Danube. © 2017
Dumitrascu M.,Institute of Geography |
Grigorescu I.,Institute of Geography |
Doroftei M.,Danube Delta National Institute |
Kucsicsa G.,Institute of Geography |
And 3 more authors.
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2013
Floodplain areas host unique ecosystems displaying particular habitats with high biodiversity hosting different species of fauna and flora. Under the recent human-induced influences, these vulnerable ecosystems become highly exposed to a wide range of environmental threats. Therefore, one of the leading pressures on habitats and biodiversity is related to biological invasions, wetland ecosystems proving to be among the most vulnerable environments to Invasive Terrestrial Plant Species (ITPS). One of the most aggressive ITPS in wetland areas is Amorpha fruticosa ranging first in terms of impact on local habitats and flora. In Romania, this ITPS is adapted to all types of environments, but it regularly prefers riparian habitats. The authors put forward a comparative approach of this ITPS in three major protected areas in Romania (both Natura 2000 and Ramsar sites): Danube Delta Biosphere Reserve, Comana Natural Park and Mureş Floodplain Natural Park. The paper will focus on assessing species' habitat requirements, key environmental driving forces (both natural and human-induced) and relevant biological indicators. © SGEM2013 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.
Jaric I.,Serbian Institute for Multidisciplinary Research |
Lenhardt M.,Sinisa Stankovic Institute for Biological Research |
Pallon J.,Lund University |
Elfman M.,Lund University |
And 4 more authors.
Environmental Biology of Fishes | Year: 2011
Sturgeon populations in the Danube River have experienced severe decline during the last several decades, mostly due to the poorly regulated fishery, river fragmentation and water pollution. This study focuses on gaining better understanding of sturgeon life history primarily by addressing the assessment of microelement accumulation in sturgeon pectoral fin rays, especially of strontium and calcium, as a method that can reveal migration patterns of anadromous sturgeons. Analysis was performed on pectoral fin samples of three anadromous Danube sturgeon species (beluga, Russian sturgeon and stellate sturgeon) by the use of a Nuclear Microprobe technique. The most frequent pattern in analyzed samples was represented by a low Sr:Ca ratio in the innermost annuli, followed by an increased ratio in the middle annuli segment, and often with a decreased ratio in the outermost annuli. Probability density estimate has revealed three distinguished maxima of the Sr:Ca ratio, 7.08 × 10-3, 8.98 × 10-3 and 9.90 × 10-3, which might correspond, respectively, to fresh, brackish and saltwater. Although the analysis of the Sr:Ca ratio in sturgeon pectoral fin rays has revealed changes that might indicate probable migration between habitats with different water salinity, further studies are needed for improvement of this method. This study represents the first analysis of this kind that was conducted on sturgeon species from the Black Sea basin. © 2010 Springer Science+Business Media B.V.
Dudu A.,University of Bucharest |
Suciu R.,Danube Delta National Institute |
Paraschiv M.,Danube Delta National Institute |
Georgescu S.E.,University of Bucharest |
And 2 more authors.
International Journal of Molecular Sciences | Year: 2011
Acipenseriformes are composed of 25 sturgeon species and two paddlefish species distributed exclusively in the northern hemisphere. The Danube River and the Black Sea were originally inhabited by six sturgeon species but two are extinct and only four are still reproducing currently in the Lower Danube: Huso huso, Acipenser stellatus, A. gueldenstaedtii and A. ruthenus. Sturgeon species hybridize more easily than other fish and the determination of pure species or hybrid status is important for conservation and for breeding in fish farms. This survey demonstrated that morphological determination of this status is not reliable and a molecular tool, based on eight microsatellites genotypes is proposed. This method, based on three successive statistical analyses including Factorial Correspondence Analysis (FCA), STRUCTURE assignation and NEWHYBRIDS status determination, showed a high efficiency in discriminating pure species specimens from F1, F2 and two kinds of backcross individuals involving three of the four reproducing Lower Danube sturgeon species. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
Tudor I.-M.,Danube Delta National Institute |
Ibram O.,Danube Delta National Institute |
Teodorof L.,Danube Delta National Institute |
Burada A.,Danube Delta National Institute |
Tudor M.,Danube Delta National Institute
Journal of Environmental Protection and Ecology | Year: 2016
This paper presents a study on the zooplankton and benthic invertebrate community in shallow lakes from Danube Delta Biosphere Reserve. Samples have been collected three times in each season except winter in 2014. At each lake zooplankton was collected with plankton net from 5 stations and benthic invertebrates with an Ekmann dredge from three stations. Additionally, environmental factors (temperature, transparency, conductivity, dissolved oxygen, total nitrogen and total phosphorus) were measured. A variety of metrics (e.g. diversity, evenness) were calculated and used to provide an image of the status of analysed community structure in investigated aquatic ecosystems. The significance of differences in composition and abundance between lakes and sampling seasons were tested using ANOVA. The main goal of the paper was to explore environmental factors underlying variation in biological community structure.
Lupu G.,Danube Delta National Institute |
Doroftei M.,Danube Delta National Institute
Brukenthal. Acta Musei | Year: 2012
Observed for the first time in south-eastern Romania by Ramme in 1951 and described as a new subspecies from Cogealac (Constanţa County), Asiotmethis limbatus motasi (Ramme, 1951) is endemic for the Romanian territory, being known only from central and southern Dobrogea. The species was discovered in-situ by its calling song and body colour, two major elements in identifying this very mobile insect. There are three major NATURA 2000 habitat types where this taxa have been identified: Subpannonic steppe grasslands described as xerophilous feathergrass steppe grasslands, dry grasslands described as hill and plateau xero-mesophilous grassland, and limestone few fallow steppe grasslands from Dobrogea described as steppe grassland on hill limestone, with an average altitude oscillating between 100 and 150 meters a.s.l.
Popescu I.,UNESCO-IHE Institute for Water Education |
Cioaca E.,Danube Delta National Institute |
Pan Q.,UNESCO-IHE Institute for Water Education |
Jonoski A.,UNESCO-IHE Institute for Water Education |
Hanganu J.,Danube Delta National Institute
Environmental Science and Policy | Year: 2015
Due to its high biodiversity the Danube Delta, in Romania, is recognized as a UNESCO World Heritage Natural Site and it is listed as a RAMSAR wetland. The Danube River variable discharges have a great impact on the habitats and the overall ecological status of the delta. One of its most vulnerable parts, from both hydrodynamic and morphological point of view is the Sontea-Fortuna wetland located in the upstream of the Danube Delta. Sontea-Fortuna wetland is susceptible to both floods and droughts. On a long term, decision makers in the area need to know which measures to implement and how these will impact/improve the environment. This article presents how a 3D hydrodynamic model can be used as support for making sound decisions regarding the management of deltaic ecosystems. In particular, the methodology is applied on the Sontea-Fortuna wetland. The case study is part of a wider research in the area, which was developed within the EnviroGRIDS EU FP7 research project. EnviroGRIDS aimed at building capacity for scientists, decision-makers and the general public in the Black Sea Catchment, through collection and sharing of environmental data and models at the basin scale. © 2014 Elsevier Ltd.