Ref ID : 2068
Wilfried Schonborn; Studies on Remains of Testacea in Cores of the Great Woryty Lake (NE-Poland). Limnologica 16(1):185-190, 1984
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Out of the Woryty lake (Poland) two cores (6 m and 10 m long) were investigated for its content of Testacea. The cores show the development of the lake from the lateglacial to its shallowing in the 19th century. It could be listed 53 species of Testacea (including 4 varieties). The most abundant species in both cores in the whole history of the lake is Centropyxis aculeata. There are some differences in the species-composition and dominance-sequence between the 6 m- and 10 m-core. In the oldest sediments from lateglacial to the Pre-boreal exclusively were found Centropyxis ecornis, Difflugia globulosa and Centropyxis aerophila. The present distribution of Difflugia globulosa corresponds to the early phase of its settlement (cold climate) and Centropyxis aerophila is an oligotrophic indicator. It can be proposed, that the lake was oligotrophic up to the Boreal. The lime-indicating genus Paraquadrula occurs in calcareous sediments of both cores. In the present cores, the preservation of shells is not so good as in cores of oligotrophic lakes. But they may be used for an analysis of rhizopods. Contrary to the 6 m-core, there are very few indicators of trophic conditions in the 10 m-core. The relationship between trophic stages and testacean indicators in the Woryty is described in a special publication. The phase of shallowing is characterized by the dominance of moss-inhabiting species.