A change in the distribution pattern of diatoms above and below the halocline in bottom sediments of the central Arkona Basin,southern Baltic

Surface sediment samples from the central Arkona Basin, southern Baltic, were investigated by diatom analysis. The samples, taken by a Niemistö sampler, included the sediment-water interface and about 2–3 centimetres of the very water-saturated sediment. The samples represent the sediments deposited in the transition layer of the halocline in the Arkona Basin and immediately above and beneath it. The distribution pattern of diatoms and diatom pieces changed, reflecting the position of the halocline.Diatom analysis is an important tool in identifying Holocene Baltic sediments, and the knowledge of recent hydrological and chemical factors and their impact on the distribution pattern of diatoms is one way to evaluate the usefulness of diatom records in postglacial Baltic marine sediments. The surface-sediment diatom assemblages can be compared with the data from postglacial Baltic offshore cores. They give prelimary indications where diatom records from Littorina or Yoldia stages could be expected.