Changes in the Lake Baikal ecosystem during the Late Pleistocene and Holocene

Issue Title: Theme:Species and Speciation in Ancient Lakes Based on the detailed temporal scale of climatic events in the Northern Hemisphere from late glaciations to Holocene, and data on variability of CO^sub 2^concentrations in the atmosphere, some abiotic indices of the ecosystem of Lake Baikal during the past 16 thousand years is reconstructed. In the Late Pleistocene, extremely low input of nutrients from the drainage area corresponded to inclement ice-thermal conditions and this resulted in an extremely low concentration of diatom algae frustules in Baikal bottom sediments. At 11-9 thousand years B.P., greater heat and moisture supply, deglaciation, enlarging of adjacent vegetated areas, and increase in weathering rate of silicon and phosphorus bearing minerals, caused the input of nutrients to the water column of Lake Baikal to substantially increase. It is likely that these circumstances, as well as improvement of physical conditions favorable for the growth of diatoms (increase of under-ice radiation, decrease of the layer of convective mixing, etc.) created the conditions for sharp intensification of diatom development in Lake Baikal eight thousand years ago.[PUBLICATION ABSTRACT]