THE RECENT PALEOLIMNOLOGY OF LAKE NICHOLLS, MOUNT FIELD NATIONAL-PARK, TASMANIA

Analyses were carried out for diatoms, spherical carbonaceous particle s, and magnetic minerals on a short sediment core from a small cirque lake, Lake Nicholls, in the Mount Field National Park, south-west Tasm ania. Catchment disturbance is not evident from the fairly constant se diment accumulation rates and magnetic analyses of the sediment record . However, there is evidence for a low level of atmospheric contaminat ion during the industrial period, which reaches a maximum at the prese nt time, but is less than in many areas of north-west Europe. Changes in the diatom assemblages recorded in the sediment core are likely to be related to factors, other than catchment change or atmospheric cont amination, such as the response of within lake processes to climate ch ange. Several diatom taxa found in the cores cannot presently be assig ned to known species. Although some of these may later be identified f ollowing this preliminary study, it seems highly likely that freshwate r lakes in south-west Tasmania contain a number of new and perhaps end emic taxa.