engleski

Zooplankton structure in ice-free vs. ice-covered shallow water bodies

The diversity of zooplankton in shallow water bodies can be very high (almost 200 taxa), even during the unvegetated period, which is confirmed by this study. The aims of this study were to determine: (i) the main triggers of zooplankton structuring during the cold period ; (ii) zooplankton assemblages in pre- and post-vegetated periods within 10 shallow water bodies located in two parts of Europe differring by the presence (Poland) or absence (Croatia) of ice cover. We observed significant differences between both investigated research areas ; e.g. higher transparency and oxygen concentration in the ice-free compared to the ice-covered water bodies. The diversity and abundance of a particular zooplankton group were higher during the post-vegetated period, which was associated with higher chlorophyll a concentration. In the pre-vegetated period algal biomass was significantly reduced by the domination of algivorous copepod larvae, which were markedly more abundant in ice-covered water bodies. Our results suggest that the presence or absence of a freezing period could induce differences in the production triggers in the following season. However, other environmental parameters should also be considered as having an important impact on the structuring of the plankton community during the cold period.

rotifers; macrophytes

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