Surface-sediment diatom assemblages and water chemistry from 42 subarctic lakes in the southwestern Yukon and northernBritish Columbia, Canada

Abstract

Modern diatom assemblages were related to surface-water chemistry from 42 lakes in the southwestern Yukon and in northern British Columbia. The lakes were alkaline (pH ranged from 7.5 to 9.4) with high specific conductance (mean = 379 µS cm-1). The lakes spanned a relatively wide range of trophic conditions, with the majority being oligotrophic or meso-eutrophic. Lake water depth, alkalinity, lake surface area, and Mg accounted for most of the variation in the diatom assemblages. Diatom assemblages most closely resembled those of the southern interior of British Columbia, where high conductance lakes are numerous, although many of the taxa were common to other northern regions, including Siberia, Alaska, and other parts of the Yukon. These data may be used in conjunction with other data from northern regions, including the Yukon and Alaska, to provide broader descriptions of environmental preferences of diatom taxa by extending the range of environmental variables such as alkalinity and specific conductance.