Comparison of quantitative Holocene temperature reconstructions using multiple proxies from a northern boreal lake

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Shala , S , Helmens , K F , Luoto , T P , Salonen , J S , Väliranta , M & Weckström , J 2017 , ' Comparison of quantitative Holocene temperature reconstructions using multiple proxies from a northern boreal lake ' , Holocene , vol. 27 , no. 11 , pp. 1745-1755 . https://doi.org/10.1177/0959683617708442

Title: Comparison of quantitative Holocene temperature reconstructions using multiple proxies from a northern boreal lake
Author: Shala, Shyhrete; Helmens, Karin F.; Luoto, Tomi P.; Salonen, J. Sakari; Väliranta, Minna; Weckström, Jan
Other contributor: University of Helsinki, Department of Geosciences and Geography
University of Helsinki, Environmental Sciences
University of Helsinki, Environmental Sciences


Date: 2017-11
Language: eng
Number of pages: 11
Belongs to series: Holocene
ISSN: 0959-6836
DOI: https://doi.org/10.1177/0959683617708442
URI: http://hdl.handle.net/10138/307516
Abstract: Four biotic proxies (plant macrofossils, pollen, chironomids and diatoms) are employed to quantitatively reconstruct variations in mean July air temperatures (T-jul) at Lake Loitsana (northern Finland) during the Holocene. The aim is to evaluate the robustness and biases in these temperature reconstructions and to compare the timing of highest T-jul in the individual reconstructions. The reconstructed T-jul values are evaluated in relation to local-scale/site-specific processes associated with the Holocene lake development at Loitsana as these factors have been shown to significantly influence the fossil assemblages found in the Lake Loitsana sediments. While pollen-based temperatures follow the classical trend of gradually increasing early-Holocene T-jul with a mid-Holocene maximum, the aquatic/wetland assemblages reconstruct higher-than-present T-jul already during the early Holocene, that is, at the peak of summer insolation. The relatively low early-Holocene July temperatures recorded by the pollen are the result of site-specific factors possibly combined with a delayed response of the terrestrial ecosystem compared with the aquatic ecosystem. Our study shows that all reconstructions are influenced at least to some extent by local factors. This finding stresses the need to evaluate quantitatively reconstructed climate values against local lake development and highlights the benefit of using multi-proxy data in Holocene climate reconstructions.
Subject: chironomids
diatoms
ecological drivers
northern boreal Fennoscandia
plant macrofossils
pollen
EASTERN-EUROPEAN RUSSIA
SUB-ARCTIC FINLAND
TREE-LINE AREA
PALEOCLIMATE RECONSTRUCTIONS
CLIMATE RECONSTRUCTIONS
CHIRONOMIDAE INSECTA
FINNISH LAPLAND
CENTRAL NORWAY
POLLEN
DIATOMS
1171 Geosciences
1172 Environmental sciences
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