CS29 Phytoplankton & Primary Production
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
CummingBF, Queen's University, Kingston, Canada, cummingb@biology.queensu.ca
Laird, K, R, Queen's University, Kingston, Canada, lairdk@biology.queensu.ca
 
DIATOMS AS INDICATORS OF ENVIRONMENTAL CHANGE IN WESTERN CANADA: AN EXAMINATION OF A 400-LAKE DATASET FROM WESTERN CANADA
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Changes in diatom assemblages in sediment cores is one of the most widely used techniques to assess the impact of human activities on lakes. This retrospective approach is necessary since little or no long-term instrumental data are available on which to assess the significance of human activities on aquatic systems. Paleolimnological techniques are also widely used to assess the significance of natural changes (e.g. climate, fires) on lake ecosystems. The assessment of anthropogenic and natural impacts from diatom assemblages rests on our knowledge of their present-day ecological requirements. Because there are 1000s of diatom taxa, it is often difficult to accurately assess their relationship to multiple environmental variables (e.g. pH. depth, ionic concentration and composition, nutrients). We assessed the relationship between diatom assemblages and limnological variables in a 400-lake dataset from western Canada that spans large gradients in lake characteristics including nutrients, lake size and depth, ionic concentration and composition. This assessment indicates that diatom assemblages can be used to assess changes in multiple environmental variables. Furthermore, this dataset vastly increases the number of suitable modern analogues that are necessary to interpret diatom assemblages from sediment cores.