Paleolimnology of Neusiedlersee, Austria

Neusiedlersee is a shallow, alkaline lake (Table 1), which came into existance by tectonic subsidence about 12000–14000 yr ago. At present, half of it is covered by Phragmites australis which developed after the lake fell dry for the last time in 1868. Due to its astatic character, with about 100–200 dry periods since the lake came into existence, most of the sediment of the open lake overlying a thick Tertiary layer presents a mixture of terrestrial and lacustrine components. Because of disturbance by wind, this lacks stratification. Preliminary investigations, however, demonstrated that within the fringing Phragmites belt — especially landward — such a stratification does still exist. In order to learn more about the history of the lake 18 deep freeze cores of between 135 and 190 cms in depth, were collected from the Phragmites belt and investigated for chemical data (see Gunatilaka, this volume) and the succession of ostracods. Most of the cores contain Tertiary material (foraminifera and ostracods) at their base, followed by a cold water fauna as indicated by the presence of Cytherissa lacustris. Indicators of high alkalinity (i.e. the remains of male Limnocythere inopinata and high salinity (Heterocypris salina) were found in only a few cores.