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Sedimentary diatoms as indicators of water quality and ecosystem change in lakes of Riding Mountain National Park of Canada

University of British Columbia

The relationship between diatoms and water quality variables was examined in Riding Mountain National Park, Manitoba. In addition, fossil diatom assemblages in Clear Lake and Lake Katherine were assessed in relation to lake trophic status. Through the use of multivariate statistical methods, including Canonical Correspondence Analysis ordination, total phosphorus was determined to be the most significant environmental variable accounting for the greatest proportion of variation among modern diatom communities. Weighted Averaging and Partial Least Squares models were developed as transfer functions to be applied to fossil diatom assemblages, facilitating inferences of historical and pre-historical total phosphorus and lake trophic state. Short core diatom assemblages provided information regarding the most recent changes in lake trophic state, including those driven by human influence, whereas long core assemblages revealed pre-historical conditions indicative of the natural lake state. Paleolimnological assessments of Clear Lake and Lake Katherine revealed a natural borderline oligo-mesotrophic state. Marked changes in the diatom communities coincide with human settlement of the area and, more recently, expanded activities, cottage and golf course development, and sewage system failure. In the most recent decades, changes meant to reduce total phosphorus input have been implemented but the diatom communities have not returned to their pre-settlement composition.

Text

2012-09-11

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/43198

Environmental Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/