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Is sandy beach of the lake an ecotone? Psammon
Rotifera in a mesotrophic Lake Kuc (Masurian Lakeland, Northern Poland) |
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Jolanta Ejsmont-Karabin
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Centre for Ecological Research, Polish Academy
of Sciences, Hydrobiological Station, Leśna 13, 11-730 Mikołajki, e-mail: jolanta@onet.pl |
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Abstract:
Is inshore, 2-cm layer of wet sand an ecotone? An attempt of this study
is to answer the question by analysing characteristic patterns of a structure
of rotifer communities inhabiting the psammolitoral zone. Psammon was sampled
from sandy shore of a mesotrophic Lake Kuc (Masurian Lakeland, Poland),
weekly from May to November 1996 and on one occasion in May 1998. Despite of
extremely unfavourable conditions of their abiotic habitat, psammon rotifers
of Lake Kuc were reaching occasionally extremely high densities. Seasonal
dynamics of numbers and structure of psammon rotifer communities reflected variable character of
their habitat. A course of the changes was similar in less variable
higropsammon and extremely variable eupsammon. Patterns formed in
psammolittoral – when illustrated with qualitative and quantitative features
of psammon rotifer communities – fit definitions of an ecosystem, an ecotone,
a part of a land/water ecotone, a microlayer in the ecosystem or a specific
boundary zone in the lake ecosystem. |
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Key words: Psammon, Rotifera,
lake, ecotone |