Magnito-mineralogicheskie i biologicheskie pokazateli donnykh otlozhenii oz. Bol’shoi Khabrei (Magneto-Mineralogical and Biological Properties of Sediments of the Lake Bolshoy Kharbey).

Nazarova, L., Frolova, L., Kosareva, L., Rudaya, N., Syrykh, L., Gafiatullina, L., Kuzina, D., Palagushkina, O., Tumanov, O., Fefilova, E. and Loskutova, O. (2014) Magnito-mineralogicheskie i biologicheskie pokazateli donnykh otlozhenii oz. Bol’shoi Khabrei (Magneto-Mineralogical and Biological Properties of Sediments of the Lake Bolshoy Kharbey). Journal of the Siberian Federal University - Bioloy, 7 (4). pp. 372-394.

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Abstract

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. Upper
part of the core is characterized by higher values of magnetic susceptibility and its components. Pollen
analysis has shown that vegetation of the region during the time of the investigated sedimentation
was dominated by conifers and by constant presence of dwarf birch, Alnus fruticosa, Ericaceae.
Herbaceous are represented mainly by sedge, reflecting local near-water vegetation. 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. The most frequent zooplanktonic taxa in the whole
core were Chydorus. cf. sphaericus, Eubosmina cf. longispina, small forms of the genera Alona.
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. At the same
time gradual succession in the local vegetation starts. Concentrations of the birch and larch pollen
decrease, and Pinus s/g Diploxylon increase. This can indicate that climate became warmer and drier.
Communities of hydrobionts are getting more diverse, the number of the acidophilic, phytophylic
taxa and taxa, characteristic for eutrophication grows. In palynospectra concentration of ferns and
sphagnum grows, which can indicate swamping, growth of littoral zone and spreading of near water
vegetation and reflects warming of climate.

Document Type: Article
Keywords: Bolshezemelskaya tundra, palaeoclimate, magnito-mineralogical analysis, pollen, cladocera, chironomids
Refereed: No
Open Access Journal?: No
ISSN: 1997-1397
Projects: Otto Schmidt Laboratory
Date Deposited: 26 May 2015 11:32
Last Modified: 25 Jan 2017 13:28
URI: http://oceanrep.geomar.de/id/eprint/28720

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