The recent palaeolimnology of Lake Nicholls,Mount Field National Park,Tasmania

Analyses were carried out for diatoms, spherical carbonaceous particles, and magnetic minerals on a short sediment core from a small cirque lake, Lake Nicholls, in the Mount Field National Park, south-west Tasmania.Catchment disturbance is not evident from the fairly constant sediment accumulation rates and magnetic analyses of the sediment record. However, there is evidence for a low level of atmospheric contamination during the industrial period, which reaches a maximum at the present 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 contamination, such as the response of within lake processes to climate change.Several diatom taxa found in the cores cannot presently be assigned to known species. Although some of these may later be identified following this preliminary study, it seems highly likely that freshwater lakes in south-west Tasmania contain a number of new and perhaps endemic taxa.