Fefi lovae Larisa B. Nazarovaa,b* , Lina R. Kosarevaa , Ludmila S. <...> Petersburg, 191186, Russia e Institute of Biology, Komi Scientifi c Centre, UB RAS, UB RAS 28 Kommunisticheskaya str., Syktyvkar, GSP-2, 167982, Russia Received 08.10.2014, received in revised form 28.10.2014, accepted 18.11.2014 Investigation of sediment cores from the lake Bolshoy Kharbey (Bolshezemelskaya tundra) was performed using magnetic-mineralogical and palaeobiological methods, including palynological, Cladocera and chironomid analysis. <...> It was shown that noticeable changes took place in the state of sediments and communities of hydrobionts. <...> Lower part of the sediments is characterized by lower ferromagnetic component, which is related to lower number of magnetotactic bacteria, producing biologically controlled magnetic minerals. <...> Larch pollen disappears gradually from the lake sediments, alongside with the increase of the concentrations of birch and Alnus fruticosa pollen. <...> Taxa characteristic for big water bodies, mainly from the family Bosminidae, dominate Cladoceran communities. <...> All rights reserved * Corresponding author E-mail address: nazarova_larisa@mail.ru # 372 # Larisa B. Nazarova, Larisa А. <...> Chironomid communities are represented mainly by acid-tolerant, temperate, littoral-sublittoral taxa. <...> In the upper layers of sediments in cladoceran and chironomid communities share of planktonic taxa increases which indicates rise of the lake level as a result of seasonal ground melting. <...> Concentrations of the birch and larch pollen decrease, and Pinus s/g Diploxylon increase. <...> Большой Харбей (Большеземельская тундра), проведенное комплексом магнито-минералогических и палеобиологических методов, включающих в себя спорово-пыльцевой, кладоцерный и хирономидный анализы, показало, что в состоянии донных отложений, составе растительности и сообществах гидробионтов произошли существенные изменения. <...> Нижняя часть керна характеризуется более низкими значениями ферромагнитной составляющей, что связано с растворением биогенных # 373 # Larisa <...>