Distribution of photosynthetic pigments and other biogenic compounds in the sediments from the Southern basin of Lake Baikal

Depth profiles of carotenoids, chlorophyll derivates, and other biogenic in dicators, such as biogenic silica (BGS), total organic carbon (TOC), total organic nitrogen (TON), and perylene, were measured in C-14-dated sediments (<2 m thick) sampled from the Southern basin of Lake Baikal. The photosynt hetic pigments, BGS, and TOC (TON) accumulated in the upper part (80 cm) of the core (dated at 12-13 ka BP), whereas biogenic perylene occurs in its l ower part (below 80 cm). Biogenic silica in the upper part shows a negative correlation with total carotenoids and no significant positive correlation with TOC and total chlorophyll a. This indicates that high contents of BGS providing oxidizing conditions in the lake stimulate aerobic decomposition of organic compounds in the water and in the surface sediments. The high c oncentrations of perylene in the lower part of the core against the backgro und of the low lake productivity suggest specific processes of sedimentatio n in the past.