Crustacean as bioindicators
Introduction Crustaceans are frequently used as bioindicators and biomonitors in various aquatic systems. One reason is that they are a very successful group of animals, distributed in a number of different habitats including marine, terrestrial and freshwater environments. They are thus interesting candidates for comparative investigations. Some of the special features of crustaceans, particularly of reproduction strategies, may be highly important for the interpretation of data from bioindicator studies using these organisms, and for the development of ecotoxicological endpoints. The focus of this presentation is on the utilisation of crustaceans, mainly freshwater species, as bioindicators or biomonitors.
The presence or absence of predators also plays an important role. Gammarus pulex, for example, is able to evaluate differences in habitat quality and to respond to it. The results showed a great variability of G. pulex under different conditions. Significant differences between populations of different streams involve population density, standing crop biomass, individual size and sex ratio. It was suggested that some of these differences were caused by pollutants or by the physical structure of the stream bed.
Biotesting method on destruction of Crustacean Daphnia Magna Method principles The technique is based on a distinction establishment between quantity of victims daphnia in analyzed test (experience) and water (control). Criterion of sharp lethal toxicity is the destruction of 50 % of daphnia and more in experience for 96 hours biotestings.
Technique 1. Water test pour in glass vessels on 100 sm 3 (experience). Other vessels fill with the same volume of the filtered water from capacities where are cultivated daphnia (control). Frequency in experience and the control the triple. 2. In each skilled and control vessel place on 10 of daphnia aged to 24 h. Them quickly transfer a glass tube in diameter 5 - 7 mm, having shipped it to water. 3. Duration of biotesting makes 96 h. During biotesting of daphnia do not feed 4. During 1, 6, 24, 48, 72, 96 h biotestings visually count up quantity live of daphnia. Live consider of daphnia which freely move in thickness of water or emerge from a bottom of a vessel not later, than through 15 seconds of its easy stirring. The others of daphnia consider as victims.
Biologists also see copepods as bioindicators, species that can be used for clearing of quality of water.
Tiny shrimp-like crustaceans that are important bioindicators of the pure potable water.
Some bioindicators concentrate polluting substances in the fabrics. Here as an example can serve the chitinous armour of crustaceans. On armours of cancers experts also establish gauges.
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