In recent decades, the ecological status of the freshwater crayfish has changed drastically from a sensitive indicator of an aquatic environment to a tolerant species that can survive in a wide range of unfavourable conditions. Despite all controversies on being or not being proper bioindicators, crayfish are a key species that plays a crucial role in the freshwater ecosystem. Regardless of whether certain crayfish possess a particular environmental sensitivity or not, all species can be used in biomonitoring investigations. The main objectives of the present thesis were development and implementation of system for continuous monitoring of water quality using crayfish as the bioindicator. Being less complex than vertebrates (e.g., fish), but being sufficiently complex compared to some other hard-shell freshwater invertebrates (e.g., mussels), crayfish present a useful biomonitoring object, which is easy to manipulate with, and which provides experimental data which is easy to obtain, analyse and interpret. The first part of this thesis is devoted to an evaluation of crayfish as suitable bioindicators. We showed that, when conducting the biomonitoring of metals in aquatic biota, crayfish have sufficient tissues for a bioaccumulation survey. For this purpose, we examined the gills, muscles and hepatopancreas. We confirmed that the hepatopancreas was the primary target for accumulation of most of the examined elements (i.e., cadmium, chromium, copper, nickel, zinc). For higher relevance, crayfish surveys were compared to fish samples collected from the same locations. The second part of this work particularly focused on water quality biomonitoring based on the evaluation of crayfish ethophysiological characteristics. We examined crayfish reactions to both chemical (i.e. chloramine, chlorides, nitrites) and natural odours (i.e., food, heterosexual conspecifics, predator, etc). This approach was shown to be simple yet at the same time, complex and efficient. Such monitoring technique is easily implemented and does not demand long, complicated analyses, since monitored parameters, locomotor and cardiac activity, are evaluated immediately in real time. However, one complication is related to the unpredictability of an animal's reactions. Because studied characteristics may often affect each other, they need to be carefully traced and interaction between measured characteristics needs to be eliminated. The usefulness of such biomonitoring is conditioned by a reliable combination of behaviour and physiology, which enables detection of complex animal responses to environmental changes. As reported in the third part, we submitted an application for a patent of the developed system, and described in the patent sensor will be protected as utility model. Moreover, other crustaceans with sufficient carapace size (e.g., shrimps, crabs, molluscs) can be successfully investigated using presented system. The only challenge is that living organism can clearly indicate disruption of ambient conditions, but cannot detect what it has caused. However, there are powerful analytical techniques now, developed exactly for accurate determination of various compounds. The heart rate is species- and conditions-specific, so it cannot be applied as unified measure for all crayfish species, while visual analysis of heartbeat primary curves can be useful for establishment of referent crayfish heart rate values at their different functional states. The final part of the thesis is devoted to this issue. In conclusion, the developed biomonitoring system was shown to be highly practical unit using noninvasive technique for investigation of crayfish reactions under model conditions, with the potential of further application at broader research and industrial arenas.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:175345 |
| Date | January 2014 |
| Creators | KUKLINA, Iryna |
| Source Sets | Czech ETDs |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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