Kusch, Stephanie ORCID: 0000-0002-2708-4975, Bennike, Ole, Wagner, Bernd ORCID: 0000-0002-1369-7893, Lenz, Matthias, Steffen, Ilona and Rethemeyer, Janet (2019). Holocene environmental history in high-Arctic North Greenland revealed by a combined biomarker and macrofossil approach. Boreas, 48 (2). S. 273 - 287. HOBOKEN: WILEY. ISSN 1502-3885

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Abstract

In this study, we use a combined biomarker and macrofossil approach to reconstruct the Holocene climate history recorded in Trifna SO, Skallingen area, eastern North Greenland. Chronological information is derived from comparison of lithological, biogeochemical and macrofossil characteristics with a well-dated record from nearby Lille Sneha SO. Following local deglaciation around c.8cal.kaBP, the local peak warmth occurred between c.7.4 and 6.2cal.kaBP as indicated by maximum macrofossil abundances of warmth-demanding plants (Salix arctica andDryas integrifolia) and invertebrates (Daphnia pulex and Chironomidae). Warm conditions were dominated by terrestrial organic matter (OM) sedimentation as implied by the alkane-based P-aq ratio, but increased aquatic productivity is indicated when temperature was highest around 6.5cal.kaBP. The n-C-29/n-C-31 alkane ratio shows that vegetation in the catchment was dominated by shrubs after deglaciation, but shifted towards relatively more grassy/herbaceous vegetation during peak warmth. After 5.4cal.kaBP, the disappearance of warmth-demanding plant and invertebrate macrofossils indicates cooling in the Skallingen area. This cooling was characterized by a significant shift towards dominance of aquatic OM sedimentation in Trifna SO as implied by high P-aq ratios. Cooling was also associated with a shift in vegetation type from dwarf-shrub heaths towards relatively more herbaceous vegetation in the catchment, stronger erosion and more oligotrophic conditions in the lake. Our data show that mean air temperatures inferred using branched glycerol dialkyl glycerol tetraethers (brGDGTs) do not seem to accurately reflect the local climatic history. Irrespective of calibration, methylation of branched tetraethers (MBT) palaeothermometry cannot be reconciled with the macrofossil evidence and seems to be biased by either changing brGDGT sources (insitu vs. soil-derived) or changing species assemblages and/or an unknown physiological responseto changing environmental conditions at high latitude.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Kusch, StephanieUNSPECIFIEDorcid.org/0000-0002-2708-4975UNSPECIFIED
Bennike, OleUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wagner, BerndUNSPECIFIEDorcid.org/0000-0002-1369-7893UNSPECIFIED
Lenz, MatthiasUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Steffen, IlonaUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Rethemeyer, JanetUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-152101
DOI: 10.1111/bor.12377
Journal or Publication Title: Boreas
Volume: 48
Number: 2
Page Range: S. 273 - 287
Date: 2019
Publisher: WILEY
Place of Publication: HOBOKEN
ISSN: 1502-3885
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
DIALKYL GLYCEROL TETRAETHERS; LAKE-SEDIMENTS; CLIMATE-CHANGE; WATER-COLUMN; INTACT POLAR; LIPIDS; PROXY; RECORD; GDGTS; COREMultiple languages
Geography, Physical; Geosciences, MultidisciplinaryMultiple languages
Refereed: Yes
URI: http://kups.ub.uni-koeln.de/id/eprint/15210

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