Ecological characteristics of modern diatom assemblages from Axel Heiberg Island (High Arctic Canada) and their application to paleolimnological inference models

Abstract

Relationships between modern surface sediment diatom assemblages and measured water chemistry variables were examined from 30 lakes and ponds on Axel Heiberg Island (Nunavut) in the Canadian High Arctic. Canonical correspondence analysis with forward selection and Monte Carlo permutation tests identified dissolved organic carbon, dissolved inorganic carbon, specific conductance, and pH as the measured environmental variables explaining significant proportions of the diatom variance. Canonical correspondence analysis axis 1 represented a gradient of specific conductance, and axis 2 was influenced primarily by pH. To increase the signal-to-noise ratio in our reconstructions, the species data sets were refined to include only taxa that had significant responses to either conductivity or pH, as determined by Huisman Olff Fresco models of species–environment relationships. Diatom-based inference models were subsequently developed for both lakewater specific conductance (r2boot= 0.75, root mean square error of prediction = 0.22) and lakewater pH (r2boot= 0.31, root mean square error of prediction = 0.57) using weighted averaging techniques. These data contribute to our understanding of diatom biogeography throughout the Canadian Arctic and have implications for regional paleoclimatic reconstructions in these climatically and environmentally sensitive regions.