Periphytic diatom assemblages from Bathurst Island, Nunavut, Canadian HighArctic: An examination of community relationships and habitat preferences

Diatoms are potentially the most important biomonitors of environmental cha nge in high arctic lakes and ponds, but to date few autecological data are available. Because of the shallow nature of many of these water bodies, a l arge proportion of taxa are periphytic and planktonic diatoms are absent fo r the most part. By determining the microhabitat and substrate preferences of these benthic diatom taxa, the potential exists to infer past changes in available habitats from fossil diatom assemblages collected from sediment cores and ultimately to reconstruct past environmental and climatic changes responsible for these shifts in habitat availability. To refine our unders tanding of high arctic diatom habitat preference, the common diatom taxa fo und on submerged moss (bryophyte), sediment, and rock substrates from lakes and ponds on Bathurst Island, Nunavut, Canadian High Arctic were examined. The relationships among key limnological variables and the common taxa fro m each habitat were examined. Many diatom taxa exhibited varying degrees of microhabitat preference, with moss representing the more unique habitat. I n addition, the following limnological variables significantly (P less than or equal to 0.05) explained the species variance for each of the three sub strates: Na+ and total nitrogen for moss; total phosphorus (filtered) and p H for rock; and Fe3+, total phosphorus (unfiltered), total nitrogen, temper ature, and pH for sediment. These data can be used to help interpret monito ring and paleolimnological studies in this environmentally sensitive region .