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Testate amoebae consist of a group of protists producing protective external coats (tests), which potentially allows them to be used in palaeoecological studies. They are known to be good indicators of several ecological parameters such as water chemistry, moisture and water table level in substrate, and especially peat moisture. Because of their strong dependence on environmental variables it is assumed that each bog microform (e.g. hummock, hollow) is characterized by a different assemblage of testate amoebae. The distribution of testate amoebae assemblages in peat bog of north-eastern Estonia was studied along the gradient from hummock to hollow in the upper 30 cm of the peat layer along a transect of 10 m. The composition and abundance of testate amoebae communities were analyzed in the samples collected (peat sampler, 5 cm diameter) from each sample point (at a distance of 2.5 m from each other) from hummock to hollow. Indicatory species specific to certain bog microforms (representing a set of environmental variables) were found, as well as other species typical for individual environment variables such as depth, peat decomposition degree, and distance to water table or local vegetation. Data analysis showed that distinct bog microforms are better described by abundance of particular testate amoebae species in peat than by species proportions in total abundance of the assemblage. The frequency of occurrence of species with dry environment preference correlates well with arboreal and Calluna vulgaris pollen and high degree of decomposition of peat; it all indicates a dryer environment and possibly is referring to a hummock microform. Amphitrema flavum correlates well with Sphagnum; this correlation increases with the A. flavum shift downwards from Sphagnum up to 4 cm. Testate amoebae assemblages in different bog microforms, even within 10 m, are distinctly different. To pay attention to possible changes of bog microforms in time is therefore crucial for reconstructing the palaeohydrological history of bogs.
The mainly purposes this paper to compare the atmospheric air contamination in different localities depending on the winter and summer season of the year, with use of the enrichment factor and the Principal Component Analysis. The lack of a clear correlation between the enriching coefficients of Pb and Cd as well Cr and Ni may indicate that over the town area masses of the air from different directions can displace and as well, some close range sources of contamination can effect it. At present, the ecotoxicological estimations established for particular contaminated areas should include the information of the similarities of metal occurrence on the base of PCA analysis.
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