engleski

Impact of different sources of dissolved organic carbon on rotifers in shallow lakes

Climate changes cause increased input of dissolved organic carbon (DOC) in shallow lake ecosystems, leading to alterations in physico-chemical factors, composition of zooplankton and food web interactions. Rotifers, as an important component of freshwater plankton, significantly contribute to the carbon transfer from lower to higher trophic levels. In this study in situ mesocosms were used to determine the impact of labile and recalcitrant carbon on lake ecosystems. The main objectives of this study were to assess: (i) structural and functional traits of rotifers ; (ii) the influence of abiotic and biotic factors on composition of rotifers ; and (iii) ecosystem recovery after impact of different sources of DOC. Higher diversity, abundance and biomass of rotifers were observed in the mesocosm with labile carbon compared to the mesocosm with recalcitrant carbon. During the experiment, planktonic nanoalgivor rotifer species (Keratella cochlearis), dominant at the beginning, were replaced by semiplanktonic detritivore species (Lecane, Lepadella) dominant at the end of the experiment with labile and mixed DOC. That shift in the rotifer assemblage was likely caused, first, by higher concentrations of chlorophyll a as well as presumably competition with crustacean algivores at the beginning, and second, higher concentrations of DOC and nutrients at the end of the experiment. The results of this study indicate the possibility of ecosystem recovery after external DOC load, replacement of species which lead to assemblage more adopted to the stressor impact, and the importance of rotifers as indicators in assessing changes on the ecological status of shallow water bodies.

Rotifers ; DOC ; mesocosm ; carbon transfer ; shalow lakes

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