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First physical evidence for forested environment in the Arctic during MIS 3.

https://arctichealth.org/en/permalink/ahliterature274217
Source
Sci Rep. 2016;6:29054
Publication Type
Article
Date
2016
Author
Pertti Sarala
Minna Väliranta
Tiina Eskola
Giedré Vaikutiené
Source
Sci Rep. 2016;6:29054
Date
2016
Language
English
Publication Type
Article
Abstract
Old sedimentological and geochronological records can be preserved underneath the central parts of the continental ice sheets under non-erosive, cold-based subglacial conditions. Organic deposits that predate the last deglaciation are of particular value for the information held on glacial-time climate and environmental conditions. In this study, we present multiproxy data derived from a well-preserved MIS 3 interstadial (55-25?ka ago) organic layer from inside the Arctic Circle in the Finnish Lapland. Biological proxy evidence, namely coming from aquatic plant species, indicates July temperatures as high as 14.4?°C, i.e. higher than those of today for the study site. Macrofossil evidence demonstrates for the first time the presence of pines accompanied by tree birch during the MIS 3 interstadial in northern Fennoscandia. These results concur with contemporary insolation model outcomes but contradict with the previous proxy-based view of open tundra conditions during the MIS 3. The data suggest that there are highly dynamic interstadial continental ice-sheet dynamics following changes in orbital forcing. Warm climate enabled the establishment of forests on exposed landscape. Moreover, we suggest that in the light of these new data, previous MIS 3 pollen data could be re-interpreted.
PubMed ID
27363905 View in PubMed
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Proxy comparison in ancient peat sediments: pollen, macrofossil and plant DNA.

https://arctichealth.org/en/permalink/ahliterature265417
Source
Philos Trans R Soc Lond B Biol Sci. 2015 Jan 19;370(1660):20130382
Publication Type
Article
Date
Jan-19-2015
Author
Laura Parducci
Minna Väliranta
J Sakari Salonen
Tiina Ronkainen
Irina Matetovici
Sonia L Fontana
Tiina Eskola
Pertti Sarala
Yoshihisa Suyama
Source
Philos Trans R Soc Lond B Biol Sci. 2015 Jan 19;370(1660):20130382
Date
Jan-19-2015
Language
English
Publication Type
Article
Keywords
Base Sequence
DNA, Plant - classification - genetics - history
Finland
Fossils
Geologic Sediments - chemistry
History, Ancient
Molecular Sequence Data
Multiplex Polymerase Chain Reaction
Pollen - genetics
Russia
Sequence Analysis, DNA - methods
Soil - chemistry
Abstract
We compared DNA, pollen and macrofossil data obtained from Weichselian interstadial (age more than 40 kyr) and Holocene (maximum age 8400 cal yr BP) peat sediments from northern Europe and used them to reconstruct contemporary floristic compositions at two sites. The majority of the samples provided plant DNA sequences of good quality with success amplification rates depending on age. DNA and sequencing analysis provided five plant taxa from the older site and nine taxa from the younger site, corresponding to 7% and 15% of the total number of taxa identified by the three proxies together. At both sites, pollen analysis detected the largest (54) and DNA the lowest (10) number of taxa, but five of the DNA taxa were not detected by pollen and macrofossils. The finding of a larger overlap between DNA and pollen than between DNA and macrofossils proxies seems to go against our previous suggestion based on lacustrine sediments that DNA originates principally from plant tissues and less from pollen. At both sites, we also detected Quercus spp. DNA, but few pollen grains were found in the record, and these are normally interpreted as long-distance dispersal. We confirm that in palaeoecological investigations, sedimentary DNA analysis is less comprehensive than classical morphological analysis, but is a complementary and important tool to obtain a more complete picture of past flora.
Notes
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PubMed ID
25487333 View in PubMed
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