NATURAL VERSUS ANTHROPOGENIC CHANGE IN LAKES - THE ROLE OF THE SEDIMENT RECORD

Recent methodological developments permit the quantitative reconstruct ion of water chemistry variables from microfossil assemblages preserve d in lake sediments. These reconstructions can be used to identify the extent and timing of disturbance to lake ecosystems. Combined with ap propriate sampling strategies, lake sediments permit water chemistry v ariables and community rates of change to be estimated at a variety of timescales. Sediments predating major cultural impacts offer the poss ibility of inferring lake history before anthropogenic interference, a nd can, therefore, contribute to current debates about timescales of n atural variance in lakes, as well as the response of lake communities to natural environmental perturbations. Such an approach has relevance to many contemporary environmental problems, e.g. acidification, eutr ophication and climate change.