TY  - JOUR
A1  - Hoff, Ulrike
A1  - Biskaborn, Boris K.
A1  - Dirksen, Veronika G.
A1  - Dirksen, Oleg
A1  - Kuhn, Gerhard
A1  - Meyer, Hanno
A1  - Nazarova, Larisa B.
A1  - Roth, Alexandra
A1  - Diekmann, Bernhard
T1  - Holocene environment of Central Kamchatka, Russia: Implications from a multi-proxy record of Two-Yurts Lake
JF  - Global and planetary change
N2  - Within the scope of Russian German palaeoenvironmental research, Two-Yurts Lake (TYL, Dvuh-Yurtochnoe in Russian) was chosen as the main scientific target area to decipher Holocene climate variability on Kamchatka. The 5 x 2 km large and 26 m deep lake is of proglacial origin and situated on the eastern flank of Sredinny Ridge at the northwestern end of the Central Kamchatka Valley, outside the direct influence of active volcanism. Here, we present results of a multi-proxy study on sediment cores, spanning about the last 7000 years. The general tenor of the TYL record is an increase in continentality and winter snow cover in conjunction with a decrease in temperature, humidity, and biological productivity after 5000-4500 cal yrs BP, inferred from pollen and diatom data and the isotopic composition of organic carbon. The TYL proxy data also show that the late Holocene was punctuated by two colder spells, roughly between 4500 and 3500 cal yrs BP and between 1000 and 200 cal yrs BP, as local expressions of the Neoglacial and Little Ice Age, respectively. These environmental changes can be regarded as direct and indirect responses to climate change, as also demonstrated by other records in the regional terrestrial and marine realm. Long-term climate deterioration was driven by decreasing insolation, while the short-term climate excursions are best explained by local climatic processes. The latter affect the configuration of atmospheric pressure systems that control the sources as well as the temperature and moisture of air masses reaching Kamchatka. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Kamchatka
KW  - North Pacific
KW  - Holocene Climate
KW  - Palaeolimnology
KW  - Diatoms
KW  - Pollen
Y1  - 2015
U6  - https://doi.org/10.1016/j.gloplacha.2015.07.011
SN  - 0921-8181
SN  - 1872-6364
VL  - 134
SP  - 101
EP  - 117
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - GEN
A1  - Fritz, Michael
A1  - Opel, Thomas
A1  - Tanski, George
A1  - Herzschuh, Ulrike
A1  - Meyer, Hanno
A1  - Eulenburg, A.
A1  - Lantuit, Hugues
T1  - Dissolved organic carbon (DOC) in Arctic ground ice
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Thermal permafrost degradation and coastal erosion in the Arctic remobilize substantial amounts of organic carbon (OC) and nutrients which have accumulated in late Pleistocene and Holocene unconsolidated deposits. Permafrost vulnerability to thaw subsidence, collapsing coastlines and irreversible landscape change are largely due to the presence of large amounts of massive ground ice such as ice wedges. However, ground ice has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements which are important for ecosystems and carbon cycling. Here we show, using biogeochemical data from a large number of different ice bodies throughout the Arctic, that ice wedges have the greatest potential for DOC storage, with a maximum of 28.6 mg L-1 (mean: 9.6 mg L-1). Variation in DOC concentration is positively correlated with and explained by the concentrations and relative amounts of typically terrestrial cations such as Mg2+ and K+. DOC sequestration into ground ice was more effective during the late Pleistocene than during the Holocene, which can be explained by rapid sediment and OC accumulation, the prevalence of more easily degradable vegetation and immediate incorporation into permafrost. We assume that pristine snowmelt is able to leach considerable amounts of well-preserved and highly bioavailable DOC as well as other elements from surface sediments, which are rapidly frozen and stored in ground ice, especially in ice wedges, even before further degradation. We found that ice wedges in the Yedoma region represent a significant DOC (45.2 Tg) and DIC (33.6 Tg) pool in permafrost areas and a freshwater reservoir of 4200 km(2). This study underlines the need to discriminate between particulate OC and DOC to assess the availability and vulnerability of the permafrost car-bon pool for ecosystems and climate feedback upon mobilization.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 493 
KW  - last glacial maximum
KW  - Beaufort Sea coast
KW  - Cape Mamontov Klyk
KW  - permafrost carbon
KW  - Laptev Sea
KW  - Lyakhovsky Island
KW  - climate-change
KW  - old carbon
KW  - hologene
KW  - Siberia
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408155
SN  - 1866-8372
IS  - 493
ER  -