A 250-year assessment of human impacts on Lake Superior: an updated paleolimnological perspective

Document
Description
To understand environmental conditions in Lake Superior over the last two centuries, we conducted a paleolimnological study on two sediment cores collected in the eastern and western regions of the lake. We examined the diatom community assemblages, trace metals, sediment characteristics, and GIS-reconstructed human land use to evaluate the historical impacts of human activities. During European settlement and agricultural development, there is clear indication the diatom community reorganized due to nutrient enrichment. Trace metal profiles tracked a period of mining and ore processing which temporarily increased metal loads to the lake in the mid- to late-20th century. In recent decades, more oligotrophic diatom species were favored, suggesting nutrient decreases associated with remedial activities. The diatom community has reorganized to be dominated by Cyclotella species, providing evidence that water quality changes are being influenced by atmospheric nitrogen deposition and changes in the lake's physical and chemical processes associated with climate change.
Date Issued
2013-05
Number of Pages
226
Decade
Associated Organization
Publisher
University of Minnesota (Minneapolis, Minnesota)
Body of Water
Rights Holder
Chraibi, Victoria Lindsay Shaw
Rights Management
Have Copyright Permission