19th Century Eutrophication of a Remote Boreal Lake: A Consequence of Climate Warming?

摘要: To investigate the response of a remote boreal lake to recent climate warming, ∼200-year varved sediment record from Rainbow Lake A (RLA), located in northern forest Wood Buffalo National Park, straddling Alberta and Northwest Territories (Canada), was investigated using diatom assemblages biogenic silica concentrations. Diatom community composition, trends diatom-inferred total phosphorus (TP) levels all showed significant changes beginning between circa 1830 1840, coincident with onset increasingly warm June/July temperatures Canada. We evaluated several hypotheses which may have caused these nutrient changes, including local anthropogenic disturbances, fires, increased atmospheric deposition nutrients or pollen, internal sources regeneration. concluded that TP is likely increasing as result enhanced cycling due either thermal stratification warmer summer and/or decreased meromictic stability. The results presented here, combination other paleolimnological research latitude regions, suggest widespread aquatic 19th century.