Abstract Our research aimed to study the long-term impacts of Cu and Zn mining across Lake Pyhäjärvi (Finland), focusing on biological community responses. We applied paleolimnological methods on two short sediment cores and two top–bottom samples (before and after mining impact), analysing metals to examine the extent of mining impact and diatom and cladoceran communities to study the ecological consequences of mining. Our results showed that mining-induced metal pollution affected the entire Lake Pyhäjärvi, and sedimentary metal concentrations were many orders of magnitude higher in the most heavily impacted basin, Junttiselkä, compared to the other analysed basins. Compared to diatom communities, cladoceran communities showed fewer temporal responses but more distinct spatial changes attributed to habitat variability. Changes in the diatom community in the most polluted basin, Junttiselkä, followed the trends in metals. Ecological changes were more subtle in the main basin of the lake, with the exception of the Emolahti sub-basin, which showed a shift to diatom taxa indicative of disturbed conditions. Our results demonstrate how the paleolimnological approach may be used to complement contemporary lake monitoring in morphologically diverse large lakes, where available monitoring data are scarce.
Atti et al. (Sun,) studied this question.