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Vliv hygienicky ošetřené vody na srdeční frekvenci raka a jejich následnou mortalitu
MALINOVSKA, Viktoriia
The study is focused on the evaluation of crayfish physiological reaction on hygienically treated water with chlorine dioxide (ClO2). A patented non-invasive monitoring system was used for observation of crayfish cardiac and locomotor activity. Monitoring was conducted from February to August 2017 under conditions of private commercial enterprise "Pivovar Protivín" in Czech Republic. Adult individuals of signal crayfish, Pacifastacus leniusculus, were kept separately in water-flow aquariums directly after the water treatment device producing ClO2 in concentration from 0.01 to 0.29 mg.l-1. Observed crayfish response to the disinfectant varied among individuals which could be explained by a different functional state and individual reaction on stimuli. Diurnal rhythm of some crayfish was disturbed even at a lower concentrations of chlorine dioxide (0.01-0.2 mg.l-1), while higher concentrations affected all animals. In addition to that, higher levels of chlorine dioxide ( 0.2 mg.l-1) significantly increased mortality. Maximum concentrations (0.2-0.29 mg.l-1) were observed 28 times in total during 202 days of monitoring, which resulted in 25 mortality cases occurred several days after exposure. In average, mortality of crayfish occurred three-four weeks after stocking to the experimental system. Possible lethal concentration of ClO2, which caused animal mortality, is 0.2 mg.l-1. Results suggested that crayfish exposure to ClO2, obviously, negatively affect their physiological processes; however, further studies are needed to examine specific effects of chlorine dioxide on internal organs of crayfish.
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Noninvasive crayfish cardiac and behavioral activities monitoring system
PAUTSINA, Aliaksandr
Crayfish provide a model which is simple, has an easily-accessible cardiovascular system and can be maintained in the laboratory conditions; the model has good utility for water quality assessment and ethophysiological studies. A noninvasive crayfish cardiac and behavioral activities monitoring (NICCBAM) system is discussed in the thesis. The system is inexpensive, has relatively few components and permits long-term continuous simultaneous monitoring of cardiac and behavioral activities of several crayfish. Moreover, compared to other available systems, it provides a novel approach of cardiac activity shape analysis which allows improving monitoring accuracy as well as obtaining additional information on crayfish functional state. The NICCBAM system was evaluated by comparing with the well-known electrocardiography system which demonstrated that cardiac contractions with both approaches were synchronous and that both signal shapes were similar. Experiments on crayfish cardiac activity relative to selected odors and chemicals demonstrated the promising potential of cardiac signal shape analysis, not only for detecting changes in the aquatic environment, but also for their classification.
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