SILICEOUS MICROFOSSIL DISTRIBUTION IN THE SURFICIAL SEDIMENTS OF LAKEBAIKAL

Examination of surficial sediments at 16 stations shows minor, but con sistent differences in the numbers and kinds of siliceous microfossils deposited in different regions of Lake Baikal. There is a general nor th-south decreasing trend in total microfossil abundance on a weight b asis. Endemic plankton diatom species are the most abundant component of assemblages at all stations. Chrysophyte cysts are present at all s tations, but most forms are more abundant at northern stations. Non-en demic plankton diatom species are most abundant at southern stations. Small numbers of benthic diatoms and sponge spicules are found in all samples. Although low numbers are present in offshore sediments, the b enthic diatom flora is very diverse. Principal components analysis con firms primary north-south abundance trends and suggests further differ entiation by station location and depth.