Diatom communities sampled in the vicinity of the Polish Antarctic Arctowski Station (King George Island, South Shetland Islands) have been investigated. Soil and sediment samples were collected from Petrified Forest Creek and Ornithologist Creek valleys. A total of 98 diatom taxa belonging to 30 different genera were recorded in the counts. Nine taxa have a marine origin but all together constitute only 0.14% of all counted valves. Three species: Staurosira pottiezii, Psammothidium germainioides and Sellaphora jamesrossensis dominated the flora. Some differences in the diatom assemblages were observed between soil samples from two stream valleys and between soil and sediments from the same catchment area. The highest species diversity was recorded in samples from the dried-up bed of the Ornithologist Creek, where both freshwater and terrestrial species were found. The soil samples from both investigated valleys showed a comparable number of species, but a different species composition. Based on the PCA analysis a clear separation of the assemblages from both creeks could be observed.
Diatom assemblages from small pools and creeks on the Ecology Glacier
forefield have been investigated. It is the first study in the Admiralty Bay region after
the thorough taxonomic revision of the non-marine Antarctic diatom flora. A total of
122 diatom taxa, belonging to 35 genera were identified. More than 55% of all observed
species have a restricted Antarctic distribution. Another 15% have a marine origin.
Nitzschia gracilis Hantzsch, N. homburgiensis Lange-Bertalot and Planothidium rostrolanceolatum
Van de Vijver et al. dominated the flora. Based on a DCA analysis,
samples were subdivided in three groups reflecting ecological differences. Several samples
(group 1) showed a mixed freshwater/marine diatom composition and are typical for
coastal pools. Two other groups were separated based on the amount of limnoterrestrial
taxa indicating the temporary character of some of the pools.