Abstract
Diatoms are the most abundant microfossils in seafloor sediments of the northern North Pacific area, but confusion over taxonomy has impaired their use in biostratigraphy and paleoecology. Analysis of more than 200 surface sediment samples revealed several distinct diatom assemblages which appear to be related to environmental regimes. Referring to original diagnoses, these assemblages can be sorted into 36 spp., of which 1, Delphineis kippae, is new.