TAXONOMY AND STRATIGRAPHY OF LATE-GLACIAL PEDIASTRUM TAXA FROM LYSMOSEN, DENMARK - A PRELIMINARY-STUDY

In 1985 parts of a skeleton of a giant deer (Megaloceros giganteus) were found in Lysmosen, a former lake situated in the south-eastern part of Jutland, Denmark. Pollen analyses and C-14-datings show that the investigated sediments cover at least the Allerod, the Younger Dryas, the Preboreal and the early Boreal. As the samples contained very well preserved coenobia of the green algal genus Pediastrum an investigation at species level was carried out. The purpose was to investigate any trends in the succession of species in Lysmosen and correlate these with changes in the environment. Thirteen taxa of Pediastrum were found. Photographs and a discussion on some difficulties concerning the identifications are given. The percentage distributions of Pediastrum taxa and selected aquatics and helophytes are presented together with a cumulative pollen diagram. Six different zones of Pediastrum taxa could be distinguished. Based on knowledge of their recent and fossil distribution combined with the information on aquatics and helophytes from the pollen diagram a developmental history of the former lake is tentatively inferred.