On the occurrence of subfossil Pediastrum algae in a Flandrian core at Kirkkonummi, southern Finland

ALHONEN, PENTTI and RISTILUOMA, SINIKKA 1973: On the occurrence of subfossil Pediastrum algae in a Flandrian core at Kirkkonummi, southern Finland. Bull. Geol. Soc. Finland 45, 73—77. Subfossil green algae of Pediastrum were observed in a Flandrian core in south-west Finland. Their greatest relative abundance was slightly above the rational border for Tilia (T0) in the pollen stratigraphy. The authors believe that the species indicate the presence of eutrophic chlorococcal plankton, thus reflecting a more or less productive environment of sedimentation. The proximity of the transgressive Litorina Sea and the contemporaneous moist Atlantic climate are also assumed to have made the physical and chemical conditions in the lake phase of the site favourable for their growth. These observations and the data from the literature show that Pediastrum provides a useful indication of environmental changes, and that its occurrences in sediments is thus deserving of attention.