Trace element bioaccumulation in benthic organisms is important part of aquatic environment pollution research, since water and sediment analysis itselfs do not provide significant information about bioavailability of contaminants and the results mostly shows just current pollution at the time of sampling. This study focuses on urban streams contamination which are currently significant source of trace elements. Botic stream was chosen as exemplary, because it is affected by many combined sewer system overflows which are sources of contamination in times of heavy rain and flood. Load several sampling took place on 10 stream sites during the year of 2012. This thesis deals with 11 trace elements concretelly Cd, Co, Cr, Cu, Hg, Ni, Zn, As, Fe, Pb and Al. Trace elements were assessed in both benthic organisms and sediment. As well taxons were selected from benthic organisms, which are widely found at any time of the reference year: caddisflies of family Hydropsychidae, leeches Erpobdella sp. and mayflies of Baetidae family. Sediment analysis included sequential extraction which divided trace elements into 4 fractions according to mobility. Based on the results, bioavailability was assessed on observed elements and correlation between concentration in bethos and sediment was tested. Finally, impact of...

Research of macroinvertebrates is currently an important part of the assessment of stream quality. Basic characteristics influencing macroinvertebrates communities in the streams are elements from the external environment influencing streams, specifically basic geographic parameters of the site, land-use in the catchment and characteristics of the banks. These elements have a considerable influence on effect of the basic parameters in the stream, which are flow, sediment structure, input of organic material and pollution. Research part of the thesis is about the parameters influencing macroinvertebrates communities. Research area of this work includes three different catchments in the upper part of Blanice catchment area near Prachtice. There is one nature stream with forest in it's catchment, stream with a predominantly meadow basin and last stream is characterized by two distinct stretches - a revitalized section and a section with concrete bottom. The subject of this diploma thesis is evaluation of diversity of macroinvertebrates communities in all streams in the research area. Thesis evaluate communities of macroinvertebrate using a wide range of indexes (BMWP score, ASTP index, EPT index a diversity indexes) and compares their diversity by using rank-abundance graph. All results are summarized...

There is a number of measures, which have been currently performed on the Brno Reservoir, with the aim at the recovery of the environment health and at the reduction of incidence of cyanobacterial water blooms. The main intervention in this efforts was the desrease of water level in 2009-2010, when the level was reduced by up to 9 m. This intervention resulted in drying of the uncovered area of the littoral bottom and in completely changed oxygen conditions in the remaining lake. The objective of my work is to evaluate changes in benthic macroinvertebrate assemblage in response to these interventions and measures. On the sites of the reservoir, selected with respect to water levels and in-depth ratios, macroinvertebrates were seasonally sampled by the Ekman grab and kick-off approach in deep muddy sites and in the littoral zone, resepctively. Samples were collected at the ?Hráz?, ?Střed?, ?Litorál?, ?Rakovec?, ?Zouvalka?, ?Rokle? and ?Horní vzdutí?. In parallel with sampling selected environmental parameters (temperature, O2) in epilimnium hypolimnium were measured. The samples were washed and conserved for later determination and quantification in the laboratory. All macroinvertebrate samples were divided into three groups: Chironomidae, Oligochaeta and Others. The result are presented in a graphical form as the biomass and density on different sites according to the years preceding the reservoir draining, during the water level decline and afterwards and discussed in association with certain abiotic factors.

Structural changes in macrozoobenthic communities and changes in chemistry in longitudinal profiles of two acidified streams in the Bohemian Forest (Czech Republic) were investigated in 2007. The progress in chemical recovery was evident in both streams, whereas zoobenthos recovery was obvious only in less acidified stream.

The presented thesis deals with the structure and composition of macrozoobenthos of Pohořský and Dobechovský brooks in the Novohradské Mountains. The evaluation was based on the collections from 10 localities carried out in July 2001, March 2002 and July 2002/2003. In addition to determination and classification of the species found, the collections have also been qualitatively evaluated with the use of the diversity index (saprobic index, Belgian Biotic index) and the similarity index. It has been found that the zoobenthos population of Pohořský and Dobechovský brooks encompasses the species of both trout and grayling zones. In most taxa it concerns characteristic representatives of clear, flowing and adequately aerated water. Mutual species similarity of macrozoobenthos population of Pohořský and Dobechovský brooks is approximately 40%. The comparison of macrozoobenthos population diversity indices of Pohořský and Dobechovský brooks has shown that the Pohořský brook bentic fauna is, according to the obtained data, richer and better balanced. From the saprobity point of view, the Pohořský brook can mainly be placed into oligosaprobic stream class. The water of Dobechovský brook oscillates between oligosaprobic and {$\beta$}-mesosaprobic level.

The "Zákolanský potok" takes part in European nature program Special Area of Conservation because of the presence of stone crayfish (Austropotamobius torentium), which is listed as threatened species. The area around brook is intensively agriculturally cultivated. Water from wastewater treatments plants is drained to the local brooks. The aim of the work was to describe diversity of macrozoobenthos on the brook called "Zákolanský potok". Further aim was to evaluate the ecological condition of the watercourse using biotic indexes. The samples of macrobenthos were taken from three profiles in five sampling periods. Profile 1 was control, profile 2 was under the wastewater treatments plants and the third profile was placed down the stream. Diversity, biomass, saprobic index, BMWP, and ASTP scores were evaluated for the community of macrozoobenthos. The saprobic index was evaluated to the beta-mezosaprobity value (2.0-2.4) in the first profile, the saprobic index on the second profile showed a relatively wide range from worse oligosaprobity to worse beta-mesosaprobity (1.2-2.4). On the third profile, the saprobic index ranged from better beta-mesosaprobity to better alpha-mesosaprobity (1.6-2.6). The BMWP and ASPT scores in all profiles refer to medium to low quality aquatic environments. The diversity of the community gained the best values on the 3rd profile, here was found with one more taxon than on the 1st profile. With increasing organic load, diversity decreased on the 2nd profile, although a more sensitive species was found here.

In my diploma thesis I reviewed the results of the collection of makrozoobentos and water chemistry on three streams, which are located on the right bank of the Lipno dam. This is a Bukový, Horský and Mlýnský stream. On these streams I watch a chemical properties of conductivity, pH and alkalinity. Of the biological i wathc diversity of each group of makrozoobentos and their abundance. I then compared the results with the values from the previous years, and assessed the gradual development of these aquatic communities.