Last Glacial Maximum environmental conditions at Andoya, northern Norway; evidence for a northern ice-edge ecological hotspot

QUATERNARY SCIENCE REVIEWS

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Article

Alsos, Inger G.¹  Sjogren, Per¹  Brown, Antony G.^1,2  Gielly, Ludovic³  Merkel, Marie Kristine Foreid¹  Paus, Aage^4,5  Lammers, Youri¹  Edwards, Mary E.^1,2  Alm, Torbjorn¹  Leng, Melanie⁶  Goslar, Tomasz⁷  Langdon, Catherine T.²  Bakke, Jostein^5,8  van der Bilt, Willem G. M.^5,8 

[1] UiT Arctic Univ Norway, Tromso Museum, N-9037 Tromso, Norway

[2] Univ Southampton, Geog & Environm Sci, Southampton SO17 1BJ, Hants, England

[3] Univ Grenoble Alpes, Lab Ecol Alpine LECA, C2 40700, F-38058 Grenoble 9, France

[4] Univ Bergen, Dept Biol Sci, N-5020 Bergen, Norway

[5] Bjerknes Ctr Climate Res, Bergen, Norway

[6] British Geol Survey, Ctr Environm Geochem, Nottingham NG12 5GG, England

[7] Adam Mickiewicz Univ, Fac Phys, Poznan, Poland

[8] Univ Bergen, Dept Earth Sci, N-5020 Bergen, Norway

关键词: Ancient DNA (aDNA);    Andoya;    Climate variability;    Environmental conditions;    Glacial survival;    Last glacial maximum;    Late Weichselian;    MIS2;    Micro-refugia;    Sedimentary DNA (sedDNA);   

DOI  :  10.1016/j.quascirev.2020.106364

来源: Elsevier

【 摘 要 】

Andoya on the NW coast of Norway is a key site for understanding the Last Glacial Maximum (LGM) in northern Europe. Controversy has arisen concerning the local conditions, especially about the timing and extent of local glacial cover, maximum July temperatures and whether pine and/or spruce could have grown there. We reviewed all existing data and add newly analysed ancient sedimentary DNA (sedaDNA), pollen, macrofossils, geochemistry and stable isotopes from three lake sediment cores from Ovre AErasvatnet. A total of 23 new dates and age-depth modelling suggests the lake has been ice-free since GI2 (<23.4 cal ka BP) and possibly GS3 (<26.7 cal ka BP). Pinus and Picea sedaDNA was found in all three cores but at such low frequencies that it could not be distinguished from background contamination. LGM samples have an exceptionally high organic matter content, with isotopic values indicating that carbon and nitrogen derive from a marine source. Along with finds of bones of the little auk (Alle alle), this indicates that the lake received guano from an adjacent bird colony. SedaDNA, pollen and macrofossil assemblages were dominated by Poaceae, Brassicaceae and Papaver, but scattered occurrence of species currently restricted to the Low Arctic Tundra Zone (July temperature of 8-9 degrees C) such as Apiaceae (sedaDNA, 8-9 degrees C), and Alchemilla alpina (macrofossil, 8-9 degrees C) were also recorded. The review of >14.7 cal ka BP data recorded 94 vascular plant taxa, of which 38% have a northern limit in Shrub Tundra or more southern vegetation zones. This unusual assemblage likely stems from a combination of proximity to ice-free water in summer, geographical isolation linked with stochastic long-distance dispersal events, and the presence of bird-fertilized habitats. The environmental reconstruction based on all records from the area does not preclude local growth of tree species, as the local climate combined with high nutrient input may have led to periodically suitable environmental 'hotspot' conditions. (C) 2020 Elsevier Ltd. All rights reserved.

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