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PALAEOHYDROLOGICAL ASPECT OF
TRANSFORMATION OF LAKES INTO PEAT BOGS DURING MIDDLE HOLOCENE ON THE
BASIS OF CLADOCERA ANALYSIS IN THE NORTHERN POLAND
Krystyna Szeroczyńska, Michał Gąsiorowski
Abstract
Cladocera
are a group of water animals, which are strongly dependent on
environmental conditions. The ratio of planktonic to littoral Cladocera
species is a widely used tool in palaeohydrological reconstruction of
lakes’ water level changes. Interpretation of this ratio is still
unclear and requires further evidence. The simplest indicator of water
level, which can be used in tracing lake-peat bog transitions, is the
presence or absence of Cladocera and the character of its
disappearance. In general, two models of Cladocera decline are
observed. The first model is characterized by a very abrupt
disappearance of all species, whereas the second one, with an
intermediate stage, is characterized by domination of specific species.
These two models are related to different types of terminal history of
the water body. Even after a total disappearance of water in the peat
bogs, there were episodes of some pioneer cladoceran species presence,
correlated with periods of humid climate.
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