engleski

The overgrow capacity of microfauna on artificial substrates exposed at vertical profile in the Lake Visovac

Background and purpose: From the limnological point of view the formation of tufa and lake sediment trough the precipitation of calcium carbonate, and development of various travertine forms are the most important characteristics of the aquatic ecosystems in karstic areas. The aim of this study was to establish the seasonal changes of overgrowth capacity by periphyton on the artificial substrates in epilimnion, metalimnion and hypolimnion in the karstic lake Visovac. Materials and methods: Periphyton biomass, species diversity, number of colonized species and their population density after one month exposition of glass slides were taken as the measure for degree of overgrowth capacity by periphyton. Results and conclusions: Taking the total periphyton biomass as the indicator of overgrowth degree, we concluded, that it was the greatest in the epilimnion, and minor in hypolimnion. Considering the seasonal changes in the periphyton biomass, the greatest overgrowth capacity was measured in spring and autumn periods, and the lowest at beginning of the winter. The major share of periphyton biomass belongs to the primary producers, and just smaller part to biomass of microfauna. Species diversity and microfauna biomass, as the parameters for overgrowth capacity of the artificial substrates, do not correspond with the values of periphyton biomass completely. The greatest number of species (79) was found on the overgrown substrates in metalimnion, and the smallest (63) in hypolimnion layer. Biomass of colonized microfauna species decreases with the depth. Seasonal oscillations of colonized microfauna were more expressed in the metalimnion and hypolimnion than in the epilimnion.

protozoa; microfauna; periphyton; karstic waters; tufa deposit

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