Planktonic diatom communities in High Arctic lakes (Store Koldewey, Northeast Greenland)

Abstract

This contribution documents with light micrographs the planktonic diatom flora in seven high arctic lakes on Store Koldewey, an island off Northeast Greenland. The lakes have maximum water depths between 6.1 and 72.0 m. Basic limnological analyses indicate that all lakes are cold, monomictic, clear, oligotrophic, and alkaline. Planktonic diatoms and chrysophyte statospores were present in all but one lake. Eight planktonic diatom taxa were identified in the phytoplankton samples: Aulacoseira islandica (O. Müller) Simonsen, Aulacoseira tethera Haworth, Aulacoseira sp. 1, Cyclotella antiqua W. Smith, Cyclotella pseudostelligera Hustedt, Cyclotella rossii Håkansson, Fragilaria tenera (W. Smith) Lange-Bertalot, and Stephanodiscus minutulus (Kützing) Cleve et Möller. Fragilaria tenera was present in two morphotypes; the "normally shaped" type and a type with abnormally shaped valves, which has mostly been recorded in metal-polluted lakes. The diatom communities were generally dominated by only one or two species. The water columns of the lakes with a water depth greater than 10 m accomodate a moderate to high proportion of primarily benthic diatoms.Key words: Greenland, High Arctic, limnology, diatoms, valve morphology.