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Diatoms collected from the top 1 cm of the surface sediment layer at seven Bering Sea stations during the Fourth Chinese National Arctic Research Expedition (4th CHINARE-Arctic) in 2010 were studied. In total, 101 taxa belonging to 38 genera were found. The species were divided into four groups: eurythermal species, boreal-temperate species, polar species, and sea-ice species. The diatom assemblages at the stations in the southwestern basin area were primarily composed of boreal-temperate species, such as Neodenticula seminae , Thalassiosira trifulta , Rhizosolenia hebetata f. hiemalis , and Actinocyclus curvatulus . The northeastern shelf stations were dominated by polar species, including Fragilariopsis oceanica , Thalassiosira antarctica spora, Thalassiosira nordenskioeldii , and Thalassiosira hyalina . The overall abundance was highest at the basin stations with 3.7 ×106 cells·g-1 of wet sediment, whereas the eastern shelf stations had the lowest abundance of 0.7×106 cells·g-1 of wet sediment (excluding the resting spores of Chaetoceros spp.). The relationship between the distribution of the surface sediment diatom assemblages and the environment is discussed. |
