Paleolimnological reconstructions of Rouyn-Noranda lakes within the zone of influence of the Horne Smelter,Québec,Canada |
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| Authors: | Aruna S Dixit S Alpay Sushil S Dixit John P Smol |
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| Institution: | (1) Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, Ontario, Canada, K7L 3N6;(2) Geological Survey of Canada, Ottawa, Ontario, Canada, K1A 0E8;(3) Present address: National Guidelines and Standards Office, Environment Canada, Ottawa, Ontario, Canada, K1A 0H3 |
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| Abstract: | Diatoms were identified and enumerated from a surface sediment calibration set of 50 lakes in northwestern Québec. The relationship
between species composition and environmental variables was examined using canonical correspondence analysis (CCA). Forward
selection and Monte Carlo permutation tests in CCA indicated that diatom species distributions in the data set are most strongly
correlated to lakewater pH. A strong (r
2
boot = 0.83) weighted averaging calibration model, that includes bootstrapped error estimates, was developed for inferring past
lakewater pH. Using this model, temporal changes in pH were reconstructed for two kettle lakes, Lac de la Pépinière and Lac
Perron. Based on limnological data, both the study lakes were expected to have recently acidified due to increased acidic
precipitation and increases in anthropogenic metal loading. However, our long-term pH inference data indicate that these lakes
were naturally acidic during pre-industrial times. Nonetheless, the rate of acidification, particularly in Lac de la Pépinière,
has accelerated in the last ∼75 years. These long-term pH records developed for the dilute lakes in northwestern Québec suggest
that the region has received increased atmospheric pollutants from the nearby Horne smelter in Rouyn-Noranda. The pH inference
profiles are markedly different from many other paleolimnological studies in acid-sensitive regions of Canada that have become
acidic primarily as a result of industrial activities.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. |
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| Keywords: | Diatoms Inference models pH reconstruction Acidification Lake sediments Rouyn-Noranda Abitibi-Timiskaming Metal mining Smelting Natural acidity |
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