Seasonal and annual variations in biological regime of lakes in an ultracontinental climate (Trans-Baikal Region of U.S.S.R)

Summary The lakes are covered 7 months with ice, but under the transparent ice (up to 180 cm thickness) a rich vegetation of phytoplankton, phytomicrobenthos and macrophyta develop and activate the bacterial and animal population. Winter production of the phytoplankton reaches 36 g/m² C and that of the phytomicrobenthos 70 g/m² C.The water levels of the lakes show fluctuations with an amplitude of 2–4 m, affecting the whole trophic system inclusive species composition, proportion and abundance of individual aquatic organisms as well as related abiotic conditions.Co-authors: E. I. Bondereva, T. N. Morozova, (primary production), A. A. Topolov, K. A. Shishkina (microbiology), V. P. Gorlachov (zooplankton), I. M. Shapovalova (zoobenthos), N. M. Pronin (fish and their parasites), V. N. Kuzmich (nutrition of fish).Co-authors: E. I. Bondereva, T. N. Morozova, (primary production), A. A. Topolov, K. A. Shishkina (microbiology), V. P. Gorlachov (zooplankton), I. M. Shapovalova (zoobenthos), N. M. Pronin (fish and their parasites), V. N. Kuzmich (nutrition of fish).