Diatoms and their relationship to environmental variables from lakes and ponds on Bathurst Island, Nunavut, Canadian High Arctic

Baseline and historical environmental data are sparse in the High Arctic, h owever diatom assemblages preserved in high arctic lake and pond sediment p rofiles can provide proxy data of past environmental changes. Ecological da ta, however, are still sparse. Diatom taxa preserved in the surficial sedim ent of lakes and ponds on Bathurst Island (75 degrees 42' N, 97 degrees 21' W), Nunavut, Canadian High Arctic, and their relationship to 34 environmen tal variables were examined using multivariate statistics. A total of 148 d iatom taxa were identified from the surface sediments of 29 study sites. Fi ve environmental variables, Fe3+, Total Phosphorus (Unfiltered) (TPU), Tota l Nitrogen (TN), Temperature (TEMP) and pH significantly (P less than or eq ual to0.05) accounted for most of the variation in the diatom assemblages. TN was also significantly correlated to other variables (e.g. TPF, DOC, POC ). A CCA constrained to TN indicated that this variable best explained the species distributions, and a weighted-averaging (WA) model was developed to infer nutrient levels from the relative abundances of the 58 dominant taxa . Interestingly, previous limnological work indicated that nitrogen most li kely limited algal production in some of these high arctic sites. This mode l may be used to quantitatively estimate past TN levels from diatom assembl ages preserved in sediment cores from Bathurst Island, and may provide a me ans to track past environmental changes in the High Arctic.