Observations on diatoms inhabiting natural and artificial substrates in Kongsfjorden, Svalbard, the Arctic

The most dramatic effects of global climate change are predicted for the Arctic, and there is a raising concern about the lack of baseline information on microalgal biodiversity. The present study was motivated by the general lack of information on species distribution of Arctic benthic diatoms and particularly studies providing photographs to facilitate morphological species identification. Diatoms were studied in samples collected from Ny Ålesund, Spitsbergen, Svalbard, during summer 2006 and spring 2008. Two types of samples were examined: diatoms scraped from ceramic tiles, immersed at 0.5 m depth (2006), and diatoms extracted from surface sediment, collected at 0.5 to 3 m depth (2008). A total number of 75 taxa belonging to 45 genera were encountered. Sixty-eight species were found in the sediment samples and 48 on the ceramic tiles, of which 41 species were found on both substrata. Common species of the tile assemblages were Fragilariopsis spp., Licmophora spp., Odontella aurita, Synedropsis hyperborea and Trachyneis aspera, while Thalassiosira spp., Diploneis spp. and Navicula spp. were common in the sediment samples. Twenty-five percent of the observed diatom species belonged to freshwater taxa brought to the fjord from surrounding meltwater and river discharges.