نتایج جستجو برای: dreissena polymorpha
تعداد نتایج: 1576 فیلتر نتایج به سال:
The zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena rostriformis bugensis) are considered as the most competitive invaders in freshwaters of Europe and North America. Although shell characteristics exist to differentiate both species, phenotypic plasticity in the genus Dreissena does not always allow a clear identification. Therefore, the need to find an accurate identifica...
گونه (zebra mussel) dreissena polymorpha شاخص آلودگی آب های شیرین، بومی حوضه دریای خزر و یک تصفیه کننده زیستی می باشد که می تواند حجم زیادی از آب را فیلتر نماید. بر این در این تحقیق سعی گردید به جهت دامنه وسیع مواد موجود در فاضلاب ، نیترات و فسفات مورد بررسی قرار گیرد . برای این منظور سه توده صدف (20، 40 و 60 گرم ) تحت آزمایشات فیلتراسیون ( از طریق کشت توام فیتوپلانکتون کلرلاو سندسموس) و جذب غی...
The first record of the quagga mussel Dreissena rostriformis bugensis (Andrusov, 1897) in Germany is described. This species has expanded its distribution area in Europe at a slower rate than the zebra mussel Dreissena polymorpha (Pallas, 1771). Recent records from the Danube in Romania and from an enclosed Rhine-Meuse estuary in The Netherlands, suggest that the MainDanube canal and River Rhin...
Considerable uncertainty exists in determination of the phylogeny among extant members of the Dreissenidae, especially those inhabiting the Ponto-Caspian basin, as multiple systematic revisions based on morphological characteristics have failed to resolve relationships within this group of bivalves. In this study we use DNA sequence analyses of two mitochondrial gene fragments, 16S rRNA and cyt...
The European zebra mussel, Dreissena polymorpha (Pallas), has recently been introduced to North American freshwaters. Dreissena exhibits a wide range of population dynamics among different European lakes. In some lakes, long-term population size is fairly constant, while populations in other lakes can fluctuate greatly from year to year. Assessments of the potential ecological and economic effe...
Limnological features of different lakes may limit the density of, or even completely restrict, populations of the European zebra mussel, Dreissena polymorpha. We developed statistical models to predict the occurrence (presence or absence) and density (number per square metre) of Dreissena in lakes, based on multivariate correlations between the density of Dreissena populations and the limnolog...
The invasion of the zebra mussel, Dreissena polymorpha, into North American waters has resulted in profound ecological disturbances and large monetary losses. This study examined the invasion history and patterns of genetic diversity among endemic and invading populations of zebra mussels using DNA sequences from the mitochondrial cytochrome oxidase I (COI) gene. Patterns of haplotype frequency...
Introduced Eurasian mussels (Dreissena polymorpha and Dreissena bugensis) colonized native unionid bivalves in the upper St. Lawrence River in the early 1990s. From 1992 to 1995, we examined the infestation and impact of Dreissena on unionids at several sites near the Island of MontrØal. Unionids suffered heavy (90100%) mortality at sites where Dreissena occurred in high densities (i.e., 4000 ...
To examine the effects of depth on the performance of the freshwater dreissenid species Dreissena polymorpha and D. rostriformis bugensis, and the brackish water dreissenid, Mytilopsis leucophaeata, a controlled experiment lasting four months was conducted in a manmade freshwater lake in the Netherlands. The three species used in the experiment were collected from other water bodies in the Neth...
The Eurasian amphipod Echinogammarus ischnus is reportedly replacing the common native amphipod Gammarus fasciatus in the Great Lakes – St. Lawrence River system. A potential mechanism for this replacement is competition mediated by resident species. Other Eurasian invaders, dreissenid mussels (Dreissena polymorpha and Dreissena bugensis), dominate rocky substrates throughout the system and mig...
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