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A 10,000-year record of Arctic Ocean sea-ice variability--view from the beach.

https://arctichealth.org/en/permalink/ahliterature101296
Source
Science. 2011 Aug 5;333(6043):747-50
Publication Type
Article
Date
Aug-5-2011
Author
Svend Funder
Hugues Goosse
Hans Jepsen
Eigil Kaas
Kurt H Kjær
Niels J Korsgaard
Nicolaj K Larsen
Hans Linderson
Astrid Lyså
Per Möller
Jesper Olsen
Eske Willerslev
Author Affiliation
Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK 1350 Copenhagen K, Denmark. svf@snm.ku.dk
Source
Science. 2011 Aug 5;333(6043):747-50
Date
Aug-5-2011
Language
English
Publication Type
Article
Abstract
We present a sea-ice record from northern Greenland covering the past 10,000 years. Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequent increase in multiyear sea ice culminated during the past 2500 years and is linked to an increase in ice export from the western Arctic and higher variability of ice-drift routes. When the ice was at its minimum in northern Greenland, it greatly increased at Ellesmere Island to the west. The lack of uniformity in past sea-ice changes, which is probably related to large-scale atmospheric anomalies such as the Arctic Oscillation, is not well reproduced in models. This needs to be further explored, as it is likely to have an impact on predictions of future sea-ice distribution.
PubMed ID
21817051 View in PubMed
Less detail

Digital elevation model and orthophotographs of Greenland based on aerial photographs from 1978-1987.

https://arctichealth.org/en/permalink/ahliterature276504
Source
Sci Data. 2016;3:160032
Publication Type
Article
Date
2016
Author
Niels J Korsgaard
Christopher Nuth
Shfaqat A Khan
Kristian K Kjeldsen
Anders A Bjørk
Anders Schomacker
Kurt H Kjær
Source
Sci Data. 2016;3:160032
Date
2016
Language
English
Publication Type
Article
Keywords
Greenland
Ice Cover
Models, Theoretical
Reproducibility of Results
Abstract
Digital Elevation Models (DEMs) play a prominent role in glaciological studies for the mass balance of glaciers and ice sheets. By providing a time snapshot of glacier geometry, DEMs are crucial for most glacier evolution modelling studies, but are also important for cryospheric modelling in general. We present a historical medium-resolution DEM and orthophotographs that consistently cover the entire surroundings and margins of the Greenland Ice Sheet 1978-1987. About 3,500 aerial photographs of Greenland are combined with field surveyed geodetic ground control to produce a 25?m gridded DEM and a 2?m black-and-white digital orthophotograph. Supporting data consist of a reliability mask and a photo footprint coverage with recording dates. Through one internal and two external validation tests, this DEM shows an accuracy better than 10?m horizontally and 6?m vertically while the precision is better than 4?m. This dataset proved successful for topographical mapping and geodetic mass balance. Other uses include control and calibration of remotely sensed data such as imagery or InSAR velocity maps.
Notes
Comment On: Science. 2012 Aug 3;337(6094):569-7322859486
Comment On: Nature. 2015 Dec 17;528(7582):396-40026672555
PubMed ID
27164457 View in PubMed
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DNA evidence of bowhead whale exploitation by Greenlandic Paleo-Inuit 4,000 years ago.

https://arctichealth.org/en/permalink/ahliterature294743
Source
Nat Commun. 2016 11 08; 7:13389
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
11-08-2016
Author
Frederik Valeur Seersholm
Mikkel Winther Pedersen
Martin Jensen Søe
Hussein Shokry
Sarah Siu Tze Mak
Anthony Ruter
Maanasa Raghavan
William Fitzhugh
Kurt H Kjær
Eske Willerslev
Morten Meldgaard
Christian M O Kapel
Anders Johannes Hansen
Author Affiliation
Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, 1350 Copenhagen, Denmark.
Source
Nat Commun. 2016 11 08; 7:13389
Date
11-08-2016
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Archaeology
Biodiversity
Bowhead Whale - genetics
DNA - genetics
DNA Damage
DNA, Plant - genetics
Fossils
Geography
Geologic sediments
Greenland
Helminths - classification
Humans
Inuits
Sequence Analysis, DNA
Time Factors
Abstract
The demographic history of Greenland is characterized by recurrent migrations and extinctions since the first humans arrived 4,500 years ago. Our current understanding of these extinct cultures relies primarily on preserved fossils found in their archaeological deposits, which hold valuable information on past subsistence practices. However, some exploited taxa, though economically important, comprise only a small fraction of these sub-fossil assemblages. Here we reconstruct a comprehensive record of past subsistence economies in Greenland by sequencing ancient DNA from four well-described midden deposits. Our results confirm that the species found in the fossil record, like harp seal and ringed seal, were a vital part of Inuit subsistence, but also add a new dimension with evidence that caribou, walrus and whale species played a more prominent role for the survival of Paleo-Inuit cultures than previously reported. Most notably, we report evidence of bowhead whale exploitation by the Saqqaq culture 4,000 years ago.
Notes
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PubMed ID
27824339 View in PubMed
Less detail

DNA evidence of bowhead whale exploitation by Greenlandic Paleo-Inuit 4,000 years ago.

https://arctichealth.org/en/permalink/ahliterature277601
Source
Nat Commun. 2016 Nov 08;7:13389
Publication Type
Article
Date
Nov-08-2016
Author
Frederik Valeur Seersholm
Mikkel Winther Pedersen
Martin Jensen Søe
Hussein Shokry
Sarah Siu Tze Mak
Anthony Ruter
Maanasa Raghavan
William Fitzhugh
Kurt H Kjær
Eske Willerslev
Morten Meldgaard
Christian M O Kapel
Anders Johannes Hansen
Source
Nat Commun. 2016 Nov 08;7:13389
Date
Nov-08-2016
Language
English
Publication Type
Article
Abstract
The demographic history of Greenland is characterized by recurrent migrations and extinctions since the first humans arrived 4,500 years ago. Our current understanding of these extinct cultures relies primarily on preserved fossils found in their archaeological deposits, which hold valuable information on past subsistence practices. However, some exploited taxa, though economically important, comprise only a small fraction of these sub-fossil assemblages. Here we reconstruct a comprehensive record of past subsistence economies in Greenland by sequencing ancient DNA from four well-described midden deposits. Our results confirm that the species found in the fossil record, like harp seal and ringed seal, were a vital part of Inuit subsistence, but also add a new dimension with evidence that caribou, walrus and whale species played a more prominent role for the survival of Paleo-Inuit cultures than previously reported. Most notably, we report evidence of bowhead whale exploitation by the Saqqaq culture 4,000 years ago.
PubMed ID
27824339 View in PubMed
Less detail

Greenland ice sheet mass balance: a review.

https://arctichealth.org/en/permalink/ahliterature261135
Source
Rep Prog Phys. 2015 Apr;78(4):046801
Publication Type
Article
Date
Apr-2015
Author
Shfaqat A Khan
Andy Aschwanden
Anders A Bjørk
John Wahr
Kristian K Kjeldsen
Kurt H Kjær
Source
Rep Prog Phys. 2015 Apr;78(4):046801
Date
Apr-2015
Language
English
Publication Type
Article
Abstract
Over the past quarter of a century the Arctic has warmed more than any other region on Earth, causing a profound impact on the Greenland ice sheet (GrIS) and its contribution to the rise in global sea level. The loss of ice can be partitioned into processes related to surface mass balance and to ice discharge, which are forced by internal or external (atmospheric/oceanic/basal) fluctuations. Regardless of the measurement method, observations over the last two decades show an increase in ice loss rate, associated with speeding up of glaciers and enhanced melting. However, both ice discharge and melt-induced mass losses exhibit rapid short-term fluctuations that, when extrapolated into the future, could yield erroneous long-term trends. In this paper we review the GrIS mass loss over more than a century by combining satellite altimetry, airborne altimetry, interferometry, aerial photographs and gravimetry data sets together with modelling studies. We revisit the mass loss of different sectors and show that they manifest quite different sensitivities to atmospheric and oceanic forcing. In addition, we discuss recent progress in constructing coupled ice-ocean-atmosphere models required to project realistic future sea-level changes.
PubMed ID
25811969 View in PubMed
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Parasitic infections and resource economy of Danish Iron Age settlement through ancient DNA sequencing.

https://arctichealth.org/en/permalink/ahliterature296181
Source
PLoS One. 2018; 13(6):e0197399
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
2018
Author
Katrine Wegener Tams
Martin Jensen Søe
Inga Merkyte
Frederik Valeur Seersholm
Peter Steen Henriksen
Susanne Klingenberg
Eske Willerslev
Kurt H Kjær
Anders Johannes Hansen
Christian Moliin Outzen Kapel
Author Affiliation
Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Source
PLoS One. 2018; 13(6):e0197399
Date
2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Archaeology
Cattle
DNA, Ancient - analysis
Denmark
Feces - parasitology
Horses - parasitology
Humans
Parasites - genetics - isolation & purification
Plants - genetics
Sequence Analysis, DNA
Sheep - parasitology
Swine - parasitology
Trichuris - genetics - isolation & purification - pathogenicity
Abstract
In this study, we screen archaeological soil samples by microscopy and analyse the samples by next generation sequencing to obtain results with parasites at species level and untargeted findings of plant and animal DNA. Three separate sediment layers of an ancient man-made pond in Hoby, Denmark, ranging from 100 BC to 200 AD, were analysed by microscopy for presence of intestinal worm eggs and DNA analysis were performed to identify intestinal worms and dietary components. Ancient DNA of parasites, domestic animals and edible plants revealed a change in use of the pond over time reflecting the household practice in the adjacent Iron Age settlement. The most abundant parasite found belonged to the Ascaris genus, which was not possible to type at species level. For all sediment layers the presence of eggs of the human whipworm Trichuris trichiura and the beef tapeworm Taenia saginata suggests continuous disposal of human faeces in the pond. Moreover, the continuous findings of T. saginata further imply beef consumption and may suggest that cattle were living in the immediate surrounding of the site throughout the period. Findings of additional host-specific parasites suggest fluctuating presence of other domestic animals over time: Trichuris suis (pig), Parascaris univalens (horse), Taenia hydatigena (dog and sheep). Likewise, alternating occurrence of aDNA of edible plants may suggest changes in agricultural practices. Moreover, the composition of aDNA of parasites, plants and vertebrates suggests a significant change in the use of the ancient pond over a period of three centuries.
Notes
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PubMed ID
29924800 View in PubMed
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Postglacial viability and colonization in North America's ice-free corridor.

https://arctichealth.org/en/permalink/ahliterature280973
Source
Nature. 2016 09 01;537(7618):45-49
Publication Type
Article
Date
09-01-2016
Author
Mikkel W Pedersen
Anthony Ruter
Charles Schweger
Harvey Friebe
Richard A Staff
Kristian K Kjeldsen
Marie L Z Mendoza
Alwynne B Beaudoin
Cynthia Zutter
Nicolaj K Larsen
Ben A Potter
Rasmus Nielsen
Rebecca A Rainville
Ludovic Orlando
David J Meltzer
Kurt H Kjær
Eske Willerslev
Source
Nature. 2016 09 01;537(7618):45-49
Date
09-01-2016
Language
English
Publication Type
Article
Keywords
Animal Migration
Animals
Bison - physiology
DNA - analysis
Deer - physiology
Forests
Fossils
Genomics
Geologic Sediments - chemistry
History, Ancient
Human Migration - history
Humans
Ice Cover
Mammoths - physiology
Models, Theoretical
North America
Pollen
Radiometric Dating
Siberia
Abstract
During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr bp), glacial retreat opened an approximately 1,500-km-long corridor between the ice sheets. It remains unclear when plants and animals colonized this corridor and it became biologically viable for human migration. We obtained radiocarbon dates, pollen, macrofossils and metagenomic DNA from lake sediment cores in a bottleneck portion of the corridor. We find evidence of steppe vegetation, bison and mammoth by approximately 12.6 cal. kyr bp, followed by open forest, with evidence of moose and elk at about 11.5 cal. kyr bp, and boreal forest approximately 10?cal. kyr bp. Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6?cal. kyr bp, are unlikely to have travelled by this route into the Americas. However, later groups may have used this north-south passageway.
Notes
Comment In: Nature. 2016 Sep 1;537(7618):43-4427509860
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PubMed ID
27509852 View in PubMed
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Spatial and temporal distribution of mass loss from the Greenland Ice Sheet since AD 1900.

https://arctichealth.org/en/permalink/ahliterature269378
Source
Nature. 2015 Dec 17;528(7582):396-400
Publication Type
Article
Date
Dec-17-2015
Author
Kristian K Kjeldsen
Niels J Korsgaard
Anders A Bjørk
Shfaqat A Khan
Jason E Box
Svend Funder
Nicolaj K Larsen
Jonathan L Bamber
William Colgan
Michiel van den Broeke
Marie-Louise Siggaard-Andersen
Christopher Nuth
Anders Schomacker
Camilla S Andresen
Eske Willerslev
Kurt H Kjær
Source
Nature. 2015 Dec 17;528(7582):396-400
Date
Dec-17-2015
Language
English
Publication Type
Article
Keywords
Climate Change - statistics & numerical data
Greenland
History, 20th Century
History, 21st Century
Ice Cover
Models, Theoretical
Observation
Photography
Reproducibility of Results
Seawater - analysis
Spatio-Temporal Analysis
Temperature
Abstract
The response of the Greenland Ice Sheet (GIS) to changes in temperature during the twentieth century remains contentious, largely owing to difficulties in estimating the spatial and temporal distribution of ice mass changes before 1992, when Greenland-wide observations first became available. The only previous estimates of change during the twentieth century are based on empirical modelling and energy balance modelling. Consequently, no observation-based estimates of the contribution from the GIS to the global-mean sea level budget before 1990 are included in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Here we calculate spatial ice mass loss around the entire GIS from 1900 to the present using aerial imagery from the 1980s. This allows accurate high-resolution mapping of geomorphic features related to the maximum extent of the GIS during the Little Ice Age at the end of the nineteenth century. We estimate the total ice mass loss and its spatial distribution for three periods: 1900-1983 (75.1?±?29.4 gigatonnes per year), 1983-2003 (73.8?±?40.5 gigatonnes per year), and 2003-2010 (186.4?±?18.9 gigatonnes per year). Furthermore, using two surface mass balance models we partition the mass balance into a term for surface mass balance (that is, total precipitation minus total sublimation minus runoff) and a dynamic term. We find that many areas currently undergoing change are identical to those that experienced considerable thinning throughout the twentieth century. We also reveal that the surface mass balance term shows a considerable decrease since 2003, whereas the dynamic term is constant over the past 110 years. Overall, our observation-based findings show that during the twentieth century the GIS contributed at least 25.0?±?9.4?millimetres of global-mean sea level rise. Our result will help to close the twentieth-century sea level budget, which remains crucial for evaluating the reliability of models used to predict global sea level rise.
Notes
Comment In: Nature. 2015 Dec 17;528(7582):341-326672549
PubMed ID
26672555 View in PubMed
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8 records – page 1 of 1.