Abstract
The exposure of fresh surfaces of sulfide-rich rocks to air and oxygenated water by retreating glaciers and degrading permafrost increases the oxidation of sulfide minerals, which is responsible for the generation of natural acid rock drainage (ARD). Applying the paleoecological analysis of morphological abnormalities in populations of a chironomid species inhabiting lakes affected by ARD through the past millennium, we tested and rejected the hypothesis that unfavorable conditions for aquatic life in the ARD-stressed lakes are largely related to the temperature increase over recent decades, responsible for the enhanced release of ARD contaminants. Our results indicate that the ARDs generated by rock glaciers in the catchments are of a long-lasting nature and the frequency of chironomid morphological deformities was significantly higher during the Little Ice Age (LIA) than during pre- or post-LIA periods, suggesting that lower water temperatures may increase the adverse impacts of ARD on aquatic invertebrates.