Sediment diatom assemblages of Mountain Lake, a subalpine ecosystem, Giles County, Virginia

ABSTRACT

Mountain Lake, Virginia is a unique, natural, oligotrophic subalpine ecosystem in the southern Appalachians. Its diatom flora, based on these and earlier studies of plankton tows and plankton settling chambers, was sparse with few species. By contrast, we found 66 diatom taxa (25 genera) in the recent sediments of Mountain Lake. Twelve of these 66 taxa are new records for the inland waters of Virginia. Hierarchical cluster analysis distinguishes seven diatom assemblages in this lake, divided between shallow (primarily pennate) and deep-water (primarily centric) assemblages. Shallow diatom assemblages are further defined by differences in epipelic, epiphytic, and possibly …