Reconstruction of Holocene lake level from diatoms, chrysophytes and organic matter in a drainage lake from the Experimental Lakes Area (northwestern Ontario, Canada) |
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Authors: | Kathleen R Laird Brian F Cumming |
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Institution: | Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 |
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Abstract: | A paleolimnological study of lake-level changes in Lake 239 (Rawson Lake), a headwater lake in the Experimental Lakes Area in northwestern Ontario, indicates large fluctuations have occurred over the Holocene. Analyses are based on diatoms, the proportion of chrysophyte scales to diatoms and organic matter content from near-shore sediment cores. Quantitative estimates of lake level are based on a diatom-inferred depth model that was developed from surficial sediments collected along several transects in Lake 239. Declines of ∼ 1-3 m occurred during the late Holocene, whereas declines of at least 8 m occurred during the more arid mid-Holocene. These results provide the first substantive evidence of large declines in lake level in northwestern Ontario during the mid-Holocene. Conditions during the mid-Holocene may provide a partial view of future conditions under increasing global temperatures. |
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Keywords: | Experimental Lakes Area Northwest Ontario Lake level Holocene Diatoms Organic matter Chrysophytes |
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