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Interdisciplinary investigations of 39 lakes of the Lubuskie Lakeland (mid-Western Poland) were undertaken in the vegetation seasons 2002–2009. The aim of presented study was to characterize the significance of charophytes as indicators of habitat differentiation of lakes using the number of species, number of communities and the percentage share in the phytolittoral area. Each lake was characterized based on the results of macrophyte vegetation, vegetation depth extent, pelagic phytoplankton biomass, lakes area, max. depth, SD visibility, pH, conductivity, O₂, total hardness, Ca, Mg, PO₄, TP, NH₄, NO₃, NO₂, N org., TN. The statistical analyses (PCA), revealed that the investigated lakes were differentiated according to the basic morphometrical and physicochemical parameters and that the differentiation was reflected in the percentage share of charophytes in phytolittoral (in general – the bigger, deeper and more clear water were the lakes, the greater part of phytolittoral was covered by charophytes). Using simple cluster analysis based on the number of different types of macrophyte communities (helophytes, elodeids, nymphaeids and charophytes) two distinct groups of lakes were distinguished. Charophyte communities were at most responsible for obtained differentiation (one group with 0 or 1 and second with 1–6 charophyte communities). The distinguished groups of lakes differed significantly as regards 12, out of all 18 considered parameters. The greatest differences were evidenced for area, max. depth, SD visibility, Ca, Mg, NH₄, NO₃, phytoplankton biomass and vegetation depth extent. Similar analyses were made for the number of charophyte species, for which the lakes were divided into four groups (0– 1, 2–3, 4–5 and 6–7 charophyte species per lake). In this case 11 parameters significantly differed between distinguished groups of lakes, showing, that better habitat conditions were in the lakes where more charophyte species were stated. The obtained results revealed that all analyzed charophyte indicators (the number of species, number of communities as well as the percentage share in the phytolittoral area) very clearly reflect habitat variation and water quality of lakes and thus may be used as valuable bioindicators of lakes condition.
The aim of this study was to characterize the spatial and temporal variability of total organic carbon concentrations in a shallow, eutrophic lake (Lake Jarosławieckie, the Wielkopolski National Park, mid­western Poland) against the background of lake habitat heterogeneity. The interrelations between TOC and chlorophyll a in different studied sites (in macrophyte communities as well as in open water sections) were also taken into account. In November 2000, March, May, June and July 2001, water samples were collected in two transects along and across the lake traversing macrophyte communities of the phytolittoral zonation (7 sites) and reaching the open water zone (mid-lake, 3 sites) and, additionally, in a site close to a beach attracting local inhabitants and tourists. Statistical analyses revealed significant temporal differentiation and reverse patterns of changes of both TOC and chlorophyll a concentrations in the studied lake, whereas the spatial one was not significant. No correlations between both parameters were found. The results of cluster analyses suggest macrophyte vegetation and its seasonal changes in development as the main factor to influence TOC concentrations.
Regarding their distribution in lakes, Chara delicatula and Chara globularis are considered species of different or even opposite ecological requirements. C. delicatula is usually reported from oligotrophic lakes, but C. globularis from more fertile ones. Within Poland, both species rarely build extensive stands in the same ecosystem. The present study was carried out in a stratified, mid-forest lake in midwestern Poland where C. delicatula had not been found earlier. Based on the physical-chemical properties and analyses of phytoplankton, a transitional, meso-eutrophic status of the lake was stated. In the group of 15 more frequent macrophyte species, C. delicatula and C. globularis were among plants predominating the lake’s macrovegetation. Both stoneworts built separate patches as well as contributed to other macrophyte assemblages. Growing under the same light and trophic conditions, the species revealed differences in ecological optima in relation to the depth of occurrence and bottom slope. The results are discussed in the context of the species identity: are C. delicatula and C. globularis separate species or forms within the same taxon?
This study was aimed at recognizing the levels of arsenic, antimony and selenium concentrations in different zones of the lake ecosystem. Total content as well as inorganic species of the studied metalloids were considered. Shallow Lake Jarosławieckie (Wielkopolski National Park) was chosen for the study reported. Water samples were collected in different macrophyte communities of the phytolittoral and in the middle of the lake in early spring and mid-summer 2002. Total concentrations of all studied metalloids in samples collected in summer were lower than in those collected in spring but not all studied mineral species of As, Sb and Se followed the same pattern of changes. Despite seasonal changeability the lack of significant spatial differentiation in the concentrations of the elements studied at the peak of the vegetation season, in particular no differences in their concentrations between the sites in the bulk water in the middle of the lake and the sites in the plant communities was stated. This finding might testify to the fact that the effect of vegetation on the concentration of the elements studied is limited.
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