engleski

Rotifer fauna reflecting the trophic state of the dam reservoir Snježnica (Bosnia and Herzegovina)

From our research carried out in the reservoir Snježnica in 2000 and 2001 it can be inferred that the same species are dominant in the zooplankton community. The differentiating factor in evaluating eutrophic state is the number of individuals of indicators. Among the established species the majority belongs to microfiltrator sedimentators, i. e. filtrators of bacteria and detritus. This means that, during the period of research, the reservoir abounded in organic detritus and bacteria. These are, for instance, Brachionus angularis, Gastropus stylifer, genus Keratella, Pompholyx sulcata. The other species are the nanophytoplankton filtrators, genus Polyarthra and Trichocerca, although the trophic belonging of the genus Trichocerca is not quite clear. In the winter the reservoir pertains to a mesotrophic degree. In the spring and summer it shows a higher eutrophication. This is more expressed on site A in the vicinity of the dam that is under a greater influence of the surrounding villages. It is generally observed that a higher eutrophication is due to a great abundance of the eutrophic species Keratella cochlearis var. tecta that is represented by over 50% in the rotifer fauna in the warm period of the year.

dam reservoir; rotifer fauna; trophic state; nutrients

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