Geography & Environment Publications
19th Century Eutrophication of a Remote Boreal Lake: A Consequence of Climate Warming?
Document Type
Article
Publication Date
8-2002
Volume
28
Issue
2
Journal
Journal of Paleolimnology
First Page
269
Last Page
281
URL with Digital Object Identifier
http://dx.doi.org/10.1023/A:1021635024757
Abstract
To investigate the response of a remote boreal lake to recent climate warming, a sim200-year varved sediment record from Rainbow Lake A (RLA), located in the northern boreal forest of Wood Buffalo National Park, straddling northern Alberta and the Northwest Territories (Canada), was investigated using diatom assemblages and biogenic silica concentrations. Diatom community composition, trends in diatom-inferred total phosphorus (TP) and biogenic silica levels all showed significant changes beginning between circa 1830 and 1840, coincident with the onset of increasingly warm June/July temperatures in northern Canada. We evaluated several hypotheses which may have caused these nutrient changes, including local anthropogenic disturbances, forest fires, increased atmospheric deposition of nutrients or pollen, and internal sources of nutrient regeneration. We concluded that TP is likely increasing as a result of enhanced internal cycling of phosphorus due to either increased thermal stratification in response to warmer summer temperatures and/or decreased meromictic stability. The results presented here, in combination with other recent paleolimnological research in northern latitude regions, suggest widespread aquatic response to increasing temperatures beginning in the 19th century.
Notes
Dr. Katrina Moser is currently a faculty member at The University of Western Ontario.