southwest greenland
Recently Published Documents


TOTAL DOCUMENTS

162
(FIVE YEARS 40)

H-INDEX

24
(FIVE YEARS 3)

2022 ◽  
Author(s):  
Mimmi Oksman ◽  
Anna Bang Kvorning ◽  
Signe Hillerup Larsen ◽  
Kristian Kjellerup Kjeldsen ◽  
Kenneth David Mankoff ◽  
...  

Abstract. Climate warming and the resulting acceleration of freshwater discharge from the Greenland Ice Sheet are impacting Arctic marine coastal ecosystems, with implications for their biological productivity. To accurately project the future of coastal ecosystems, and place recent trends into perspective, paleo-records are essential. Here, we present late 19th century to present runoff estimates for a large sub-Arctic fjord system (Nuup Kangerlua, southwest Greenland) influenced by both marine- and land-terminating glaciers. We followed a multiproxy approach to reconstruct spatial and temporal trends in primary production from four sediment cores, including diatom fluxes and assemblage composition changes, biogeochemical and sedimentological proxies (total organic carbon, nitrogen, C / N-ratio, biogenic silica, δ13C, δ15N, grain size distribution). We show that an abrupt increase in freshwater runoff in the mid-1990’s is reflected by a 3-fold increase in biogenic silica fluxes in the glacier-proximal area of the fjord. In addition to increased productivity, freshwater runoff modulates the diatom assemblages and drives the dynamics and magnitude of the diatom spring bloom. Our records indicate that marine productivity is higher today than it has been at any point since the late 19th century and suggest that increased mass loss of the Greenland Ice Sheet is likely to continue promoting high productivity levels at sites proximal to marine-terminating glaciers. We highlight the importance of paleo-records in offering a unique temporal perspective on ice-ocean-ecosystem responses to climate forcing beyond existing remote sensing or monitoring time-series.


Author(s):  
Anna Maria Roos ◽  
Mary Gamberg ◽  
Derek Muir ◽  
Anna Kärrman ◽  
Pernilla Carlsson ◽  
...  

AbstractLivers of caribou and reindeer (Rangifer tarandus) from Canada (n = 146), Greenland (n = 30), Svalbard (n = 7), and Sweden (n = 60) were analyzed for concentrations of eight perfluoroalkyl carboxylic acids and four perfluoroalkane sulfonic acids. In Canadian caribou, PFNA (range < 0.01–7.4 ng/g wet weight, ww) and PFUnDA (<0.01–5.6 ng/g ww) dominated, whereas PFOS predominated in samples from South Greenland, Svalbard, and Sweden, although the highest concentrations were found in caribou from Southwest Greenland (up to 28 ng/g ww). We found the highest median concentrations of all PFAS except PFHxS in Akia-Maniitsoq caribou (Southwest Greenland, PFOS 7.2–19 ng/g ww, median 15 ng/g ww). The highest concentrations of ΣPFAS were also found in Akia-Maniitoq caribou (101 ng/g ww) followed by the nearby Kangerlussuaq caribou (45 ng/g ww), where the largest airport in Greenland is situated, along with a former military base. Decreasing trends in concentrations were seen for PFOS in the one Canadian and three Swedish populations. Furthermore, PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed decreasing trends in Canada’s Porcupine caribou between 2005 and 2016. In Sweden, PFHxS increased in the reindeer from Norrbotten between 2003 and 2011. The reindeer from Västerbotten had higher concentrations of PFNA and lower concentrations of PFHxS in 2010 compared to 2002. Finally, we observed higher concentrations in 2010 compared to 2002 (albeit statistically insignificant) for PFHxS in Jämtland, while PFNA, PFDA, PFUnDA, PFDoDA, and PFTrDA showed no difference at all.


Author(s):  
Flemming Ravn Merkel ◽  
Jannie Fries Linnebjerg ◽  
Ole Norden Andersen ◽  
Nicholas Per Huffeldt ◽  
Teunis Jansen ◽  
...  

Southwest Greenland constitutes an internationally important wintering area for seabirds, including thick-billed murres (Uria lomvia Linnaeus, 1758), but their prey may be affected by the general warming of this sub-Arctic region. We compare murre diet collected in winter in the 1990s and 2010s around Nuuk. Fish made up 36% of the diet (wet mass) and crustaceans 63% in the 1990s, changing to 22% and 78% in the 2010s, respectively. Capelin (Mallotus villosus Müller, 1776) was the dominant fish species, and the smaller contribution in the 2010s coincided with declining densities of capelin around Nuuk. The crustaceans were dominated by two krill species, Meganyctiphanes norvegica M. Sars, 1857, and Thysanoessa inermis Krøyer, 1846. However, M. norvegica was only important in the 2010s (51% wet mass), while T. inermis was dominating the 1990s with 62% wet mass and only 23% in 2010s. The dominance of M. norvegica in the 2010s confirmed our expectations of a gradual “borealization” of this region due to the generally warming sub-Arctic. The smaller contribution of fish in the diet may also support the hypothesis of deteriorating winter conditions for murres. Apart from the diet, plastic was found in 15% of the birds and 53% had parasitic nematods.


2021 ◽  
pp. 1-12
Author(s):  
Åsa K. Rennermalm ◽  
Regine Hock ◽  
Federico Covi ◽  
Jing Xiao ◽  
Giovanni Corti ◽  
...  

Abstract Refreezing of meltwater in firn is a major component of Greenland ice-sheet's mass budget, but in situ observations are rare. Here, we compare the firn density and total ice layer thickness in the upper 15 m of 19 new and 27 previously published firn cores drilled at 15 locations in southwest Greenland (1850–2360 m a.s.l.) between 1989 and 2019. At all sites, ice layer thickness covaries with density over time and space. At the two sites with the earliest observations (1989 and 1998), bulk density increased by 15–18%, in the top 15 m over 28 and 21 years, respectively. However, following the extreme melt in 2012, elevation-detrended density using 30 cores from all sites decreased by 15 kg m−3 a−1 in the top 3.75 m between 2013 and 2019. In contrast, the lowest elevation site's density shows no trend. Thus, temporary build-up in firn pore space and meltwater infiltration capacity is possible despite the long-term increase in Greenland ice-sheet melting.


2021 ◽  
Vol 268 ◽  
pp. 107101
Author(s):  
Anders E. Carlson ◽  
Alberto V. Reyes ◽  
Kaja Sillett ◽  
Klaus M. Wilcken ◽  
Dylan H. Rood

2021 ◽  
Author(s):  
Evgeniy V. Kulakov ◽  
Trond H. Torsvik ◽  
Pavel V. Doubrovine ◽  
Trond Slagstad ◽  
Morgan Ganerød ◽  
...  

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hugo K. H. Olierook ◽  
Christopher L. Kirkland ◽  
Julie A. Hollis ◽  
Nicholas J. Gardiner ◽  
Chris Yakymchuk ◽  
...  

AbstractZircon U-Pb geochronology places high-temperature geological events into temporal context. Here, we present a comprehensive zircon U-Pb geochronology dataset for the Meso- to Neoarchean Maniitsoq region in southwest Greenland, which includes the Akia Terrane, Tuno Terrane, and the intervening Alanngua Complex. The magmatic and metamorphic processes recorded in these terranes straddle a key change-point in early Earth geodynamics. This dataset comprises zircon U-Pb ages for 121 samples, including 46 that are newly dated. A principal crystallization peak occurs across all three terranes at ca. 3000 Ma, with subordinate crystallization age peaks at 3200 Ma (Akia Terrane and Alanngua Complex only), 2720 Ma and 2540 Ma. Metamorphic age peaks occur at 2990 Ma, 2820–2700 Ma, 2670–2600 Ma and 2540 Ma. Except for one sample, all dated metamorphic zircon growth after the Neoarchean occurred in the Alanngua Complex or within 20 km of its boundaries. This U-Pb dataset provides an important resource for addressing Earth Science topics as diverse as crustal evolution, fluid–rock interaction and mineral deposit genesis.


2021 ◽  
pp. 1-11
Author(s):  
Kang Yang ◽  
Laurence C. Smith ◽  
Matthew G. Cooper ◽  
Lincoln H. Pitcher ◽  
Dirk van As ◽  
...  

Abstract Supraglacial lakes and rivers dominate the storage and transport of meltwater on the southwest Greenland Ice Sheet (GrIS) surface. Despite functioning as interconnected hydrologic networks, supraglacial lakes and rivers are commonly studied as independent features, resulting in an incomplete understanding of their collective impact on meltwater storage and routing. We use Landsat 8 satellite imagery to assess the seasonal evolution of supraglacial lakes and rivers on the southwest GrIS during the 2015 melt season. Remotely sensed meltwater areas and volumes are compared with surface runoff simulations from three climate models (MERRA-2, MAR 3.6 and RACMO 2.3), and with in situ observations of proglacial discharge in the Watson River. We find: (1) at elevations >1600 m, 21% of supraglacial lakes and 28% of supraglacial rivers drain into moulins, signifying the presence of high-elevation surface-to-bed meltwater connections even during a colder-than-average melt season; (2) while supraglacial lakes dominate instantaneous surface meltwater storage, supraglacial rivers dominate total surface meltwater area and discharge; (3) the combined surface area of supraglacial lakes and rivers is strongly correlated with modeled surface runoff; and (4) of the three models examined here, MERRA-2 runoff yields the highest overall correlation with observed proglacial discharge in the Watson River.


2021 ◽  
Vol 17 (1) ◽  
pp. 419-450
Author(s):  
Nicolás E. Young ◽  
Alia J. Lesnek ◽  
Josh K. Cuzzone ◽  
Jason P. Briner ◽  
Jessica A. Badgeley ◽  
...  

Abstract. Sometime during the middle to late Holocene (8.2 ka to ∼ 1850–1900 CE), the Greenland Ice Sheet (GrIS) was smaller than its current configuration. Determining the exact dimensions of the Holocene ice-sheet minimum and the duration that the ice margin rested inboard of its current position remains challenging. Contemporary retreat of the GrIS from its historical maximum extent in southwestern Greenland is exposing a landscape that holds clues regarding the configuration and timing of past ice-sheet minima. To quantify the duration of the time the GrIS margin was near its modern extent we develop a new technique for Greenland that utilizes in situ cosmogenic 10Be–14C–26Al in bedrock samples that have become ice-free only in the last few decades due to the retreating ice-sheet margin at Kangiata Nunaata Sermia (n=12 sites, 36 measurements; KNS), southwest Greenland. To maximize the utility of this approach, we refine the deglaciation history of the region with stand-alone 10Be measurements (n=49) and traditional 14C ages from sedimentary deposits contained in proglacial–threshold lakes. We combine our reconstructed ice-margin history in the KNS region with additional geologic records from southwestern Greenland and recent model simulations of GrIS change to constrain the timing of the GrIS minimum in southwest Greenland and the magnitude of Holocene inland GrIS retreat, as well as to explore the regional climate history influencing Holocene ice-sheet behavior. Our 10Be–14C–26Al measurements reveal that (1) KNS retreated behind its modern margin just before 10 ka, but it likely stabilized near the present GrIS margin for several thousand years before retreating farther inland, and (2) pre-Holocene 10Be detected in several of our sample sites is most easily explained by several thousand years of surface exposure during the last interglaciation. Moreover, our new results indicate that the minimum extent of the GrIS likely occurred after ∼5 ka, and the GrIS margin may have approached its eventual historical maximum extent as early as ∼2 ka. Recent simulations of GrIS change are able to match the geologic record of ice-sheet change in regions dominated by surface mass balance, but they produce a poorer model–data fit in areas influenced by oceanic and dynamic processes. Simulations that achieve the best model–data fit suggest that inland retreat of the ice margin driven by early to middle Holocene warmth may have been mitigated by increased precipitation. Triple 10Be–14C–26Al measurements in recently deglaciated bedrock provide a new tool to help decipher the duration of smaller-than-present ice over multiple timescales. Modern retreat of the GrIS margin in southwest Greenland is revealing a bedrock landscape that was also exposed during the migration of the GrIS margin towards its Holocene minimum extent, but it has yet to tap into a landscape that remained ice-covered throughout the entire Holocene.


Sign in / Sign up

Export Citation Format

Share Document