TY  - JOUR
A1  - Palagushkina, Olga V.
A1  - Wetterich, Sebastian
A1  - Schirrmeister, Lutz
A1  - Nazarova, Larisa B.
T1  - Modern and fossil diatom assemblages from Bol’shoy Lyakhovsky Island (New Siberian Archipelago, Arctic Siberia)
JF  - Contemporary Problems of Ecology
N2  - This article discusses the results of a taxonomic and ecological investigation of diatoms from polygonal ponds and Quaternary permafrost deposits of Bol’shoy Lyakhovsky Island (New Siberian Archipelago) and the reconstruction of climatic changes on the Island during late Pleistocene/Holocene transition using fossil diatom assemblages from the permafrost deposits. The taxonomic list of diatoms includes 159 diatom species. The main ecological factors that determine the distribution of diatoms in the investigated data set are mean July air temperature, рН, electrical conductivity, water depth, and concentrations of Si4+ and Al3+. An increase in water depth and stable lacustrine conditions in the Lateglacial–Holocene in the ancient thermokarst lake relate to Lateglacial warming before 11860 ± 160 years BP and during the early Holocene between 11210 ± 160 and 7095 ± 60 years BP.
KW  - Pleistocene
KW  - Holocene
Y1  - 2017
U6  - https://doi.org/10.1134/S1995425517040060
SN  - 1995-4255
SN  - 1995-4263
VL  - 10
SP  - 380
EP  - 394
PB  - Pleiades Publ.
CY  - New York
ER  - 
TY  - JOUR
A1  - Pestryakova, Luidmila Agafyevna
A1  - Herzschuh, Ulrike
A1  - Wetterich, Sebastian
A1  - Ulrich, Mathias
T1  - Present-day variability and Holocene dynamics of permafrost-affected lakes in central Yakutia (Eastern Siberia) inferred from diatom records
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Thermokarst lakes are assumed to develop cyclically, driven by processes that are triggered by climate and maintained by internal feedbacks that may trigger lake drainage. However, the duration of these cycles remains uncertain, as well as whether or not they affect the stabilization of lake ecosystems in permafrost regions over millennial time scales. Our research has combined investigations into modern lake-to-lake variability with a study of the long-term development of individual lakes. We have investigated the physico-chemical and diatom compositions of a set of 101 lakes with a variety of different origins in central Yakutia (Eastern Siberia), including thermokarst lakes, fluvial-erosion thermokarst lakes, fluvial-erosion lakes, and dune lakes. We found a significant relationship between lake genesis and the present-day variability in environmental and diatom characteristics, as revealed by multi-response permutation procedures, indicator species analyses, and redundancy analyses. Environmental parameters also exhibit a significant correlation with variations in the diatom data, for which they may have been to a substantial extent responsible. Mg and SO4 concentrations, together with pH and water depth, were identified as the most important parameters, influencing the variations in the diatom data almost as much as the entire environmental parameter set. We were therefore able to establish a robust Mg-diatom transfer function, which was then applied to three Holocene lake records. From these reconstructions, together with a general interpretation of the diatom record (including, e.g., the ratio between benthic/epiphytic and planktonic taxa), we have been able to infer that all three of these lakes show (1) a continuous record with no desiccation events, (2) high lake water-levels during the early Holocene, (3) centennial to millennial scale variability, and (4) high levels of variability during the early Holocene but rather stable conditions during the late Holocene (a feature that is also known from other sites around the world). We therefore concluded that the development of these three lakes was mainly driven directly by the climate, rather than by thaw lake cycling.
KW  - Diatoms
KW  - Holocene
KW  - Thaw lakes
KW  - Thermokarst
KW  - Alas
KW  - Central Yakutia
KW  - Alkalinity
Y1  - 2012
U6  - https://doi.org/10.1016/j.quascirev.2012.06.020
SN  - 0277-3791
VL  - 51
SP  - 56
EP  - 70
PB  - Elsevier
CY  - Oxford
ER  -