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The results of a study of littoral maeroinvertebrate communities of lakes in the Wei River catchment (central Poland) are presented. Semi-quantitative sampling was performed in April and October 2009. Redundancy analysis (RDA) was used to demonstrate relationships between maeroinvertebrate assemblages and environmental variables. There were significant relationships between transparency (Secchi depth), P-PO₄ concentration, lake area, and taxa occurrence, which explained 22%, 19%, and 14% of the observed variability, respectively. The lakes were grouped according to littoral fauna communities in a pattern similar to that noted with regard to physicochemical variables and other communities inhabiting the lakes.
This paper analyzes whether physicochemical properties significantly influence the occurrence of zooplankton in a brackish reservoir. The studies were carried out on the Vistula Lagoon in August and September from 2006 to 2009 at 32 research sites. The environmental conditions in the Vistula Lagoon varied widely. At the time of the investigation, 17 species of rotifers, six species of Cladocera, and ten species of Copepoda were noted, and the total density of plankton fauna ranged from 145 to 765 ind. dm3. Statistical analysis demonstrated a significant correlation between the occurrence of some zooplankton species and certain environmental parameters, whereas the sampling sites were grouped according to study years. The zooplankton systems recorded at the research sites in 2006 constitute the most disparate group. Thus, it can be concluded that physicochemical properties might significantly impact both individual species (depending on their environmental demands) and entire zooplankton clusters.
Water quality of the Nida River (NE Poland) was evaluated using the BMWP-PL biotic and diversity indices. Revitalization works were undertaken in the river during the study. Benthic macroinvertebrate samples were collected from seven different sites. Twenty-four taxa in total were recorded. Most of the studied sites (59%) were ranked into water quality class III, while 35% of sites were of poor water quality (class IV). Good water quality (class II) was found at only one site (the upper Nida section). The revitalization works did not significantly change values of the BMWP-PL index at the studied sites.
This paper focuses on the qualitative and quantitative characterization of zooplankton in a section of the Nida (the Upper Wkra) River subjected to revitalization treatments. At four established sites, biological samples were taken for analyses. In total, 44 taxa of zooplankton were determiend in the collected material. The upper section of the Wkra River, along which two sites were set up, was in general more varied in species composition, and the structure of biocenosis was shaped by rotifers and protozoa (mainly ameba species) in nearly equal halves. At the other two sampling sites, localized below, along a further section of the watercourse, the structure of zooplankton was poorer. It was colonized by larger numbers of individuals belonging to a few species of rotifers, among which Keratella cochlearis var. tecta, Trichocerca similis and T. pusilla are the species indicating a raised level of the trophy of the river water.
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