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  • 1
    Publication Date: 2016-12-17
    Description: We demonstrate the use of the anisotropy of magnetic susceptibility (AMS) method to determine the orientation of the principal tectonic strain directions developed during the formation of the West Spitsbergen Fold-and-Thrust Belt (WSFTB). The AMS measurements and extensive rock-magnetic studies of the Lower Triassic rocks reported here were focused on the recognition of the magnetic fabric, the identification of ferromagnetic minerals and an estimation of the influence of ferro- and paramagnetic minerals on magnetic susceptibility. At most sites, the paramagnetic minerals controlled the magnetic susceptibility, and at only one site the impact of ferromagnetic minerals was higher. The AMS technique documented the presence of different types of magnetic fabrics within the sampled sites. At two sites, a normal (Kmin perpendicular to the bedding) magnetic fabric of sedimentary origin was detected. This was associated with a good clustering of the maximum AMS axes imposed by tectonic strain. The Kmax magnetic lineation directions obtained here parallel the general NNW–SSE trend of the WSFTB fold axial traces and thrust fronts. The two other investigated sites possessed mixed and inverted fabrics, the latter of which appear to reflect the presence of iron-bearing carbonates. Keywords: AMS; Eurekan orogeny; tectonic strain; rock-magnetism; Hornsund–Sørkapp area; magnetic fabric. (Published: 16 December 2016) Citation: Polar Research 2016, 35, 31683,http://dx.doi.org/10.3402/polar.v35.31683
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  • 2
    Publication Date: 2016-12-16
    Description: A lake sediment sequence from southern Store Koldewey, north-east Greenland, has been investigated using a multidisciplinary approach, including geophysical, geochemical, biogeochemical, biological and sedimentological methods. Chronological constraints are provided by accelerator mass spectrometry (AMS) 14 C dating of bulk sediment and complemented with published water moss ages. The record consists of three major sediment units. Their individual structural, textural, geophysical and geochemical characteristics indicate variable input of sediment and meltwater due to variable proximity of the ice margin and therefore reflect the growth and decay of a local glacier during the late Weichselian. Radiocarbon dating of bulk sediment samples from the lowermost unit gave ages of 42 to 34 calibrated thousand years (cal Ky B.P.) and indicates that this material is redeposited in the lake basin during or after the ice advance at the end of the Pleistocene. Increased meltwater and sediment input from a retreating ice margin following the Younger Dryas is indicated by the occurrence of a sandy to gravely section. Fine-grained and laminated sediments were deposited during the Pleistocene–Holocene transition and indicate calm sedimentation conditions with an ice margin outside of the lake catchment. The reoccurrence of coarse sediments during the early Holocene may indicate increased meltwater input in response to the cold spell at about 9.3 Kya with increased snow accumulation rather than fluctuations of local glaciers. The dating results furthermore show that AMS 14 C dating of bulk sediment samples deposited during glacier decay in High Arctic environments can give problematic ages. Keywords: North-east Greenland; Greenland Ice Sheet; Last Glacial Maximum; deglaciation; lake sediment. (Published: 15 December 2016) Citation: Polar Research 2016, 35 , 21912,http://dx.doi.org/10.3402/polar.v35.21912
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  • 3
    Publication Date: 2016-12-16
    Description: Antarctic Treaty Consultative Parties are entitled to participate in consensus-based governance of the continent through the annual Antarctic Treaty Consultative Meetings. To acquire consultative status, an interested Party must demonstrate “substantial research activity,” but no agreed mechanism exists to determine whether a Party has fulfilled this criterion. Parties have generally demonstrated substantial research activity with the construction of a research station, as suggested within the Treaty itself. However, this largely demonstrates logistical capacity, rather than research activity, and often results in major and persistent impacts on Antarctic terrestrial environments. Our study found that national investment in Antarctic infrastructure, estimated by the number of bed spaces at stations, was not a reliable indicator of scientific output. Therefore, we investigated metrics to evaluate research activity directly, and identified both the overall number of Antarctic papers and the proportion of national scientific output these represented as meaningful metrics. Such metrics could (1) demonstrate a nation’s level of research activity in Antarctica or (2) help Consultative Parties assess the level of research activity undertaken by a Party seeking to acquire consultative status. Our data showed that, even without land-based Antarctic infrastructure, Canada, Denmark and Switzerland may have reasonable grounds to demonstrate “substantial research activity” on a level comparable with existing Consultative Parties. The use of these metrics may help dispel any perceived requirement for the establishment of a research station to reach consultative status, by putting a greater emphasis on generation of scientific research outputs rather than construction of Antarctic infrastructure. Keywords: Environmental Protocol; scientific output; geopolitics; human impact; Antarctic infrastructure; bibliometric search. (Published: 15 December 2016) Citation: Polar Research 2016, 35 , 34061,http://dx.doi.org/10.3402/polar.v35.34061
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  • 4
    Publication Date: 2016-12-01
    Description: In this study, we present Lagrangian diagnostics to quantify changes in the dynamical characteristics of the Arctic sea-ice cover from 2006 to 2014. Examined in particular is the evolution in finite-time Lyapunov exponents (FTLEs), which monitor the rate at which neighbouring particle trajectories diverge, and stretching rates throughout the Arctic. In this analysis, we compute FTLEs for the Arctic ice-drift field using the 62.5 km daily sea-ice motion vector data from the European Organisation for the Exploitation of Meteorological Satellites Ocean and Sea Ice Satellite Application Facility. Results from the FTLE analysis highlight the existence of three distinct dynamical regions with strong stretching, captured by FTLE maxima or ridges. It is further shown that FTLE ridges are dominated by shear, with contributions from divergence in the Beaufort Sea. Localization of FTLE features following the 2012 record minimum in summertime sea-ice extent illustrates the emergence of an Arctic characterized by increased mixing. Results also demonstrate higher FTLEs in years when lower multi-year ice extent is observed. Keywords: sea-ice dynamics; FTLE; Arctic Ocean; Lagrangian diagnostics; LAD (Published: 30 November 2016) Citation: Polar Research 2016, 35 , 30778,http://dx.doi.org/10.3402/polar.v35.30778
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  • 5
    Publication Date: 2016-11-10
    Description: Sponges are important components of high-latitude benthic communities, but their diversity and abundance in algal-dominated rocky reefs has been underestimated because of the difficulty of in situ identification. Further, the influence of canopy-forming algae on sponge richness has been poorly studied in southern high-latitude rocky reefs compared to other latitudes. Here, we quantified taxon richness of sponges in algae-dominated rocky reefs at three sites in the western Antarctic Peninsula (62–64° S) and two sites in the Magellan region (53° S). We found higher sponge richness at sites in Antarctica (15) than in Magallanes (8), with Antarctic sponge richness higher than that reported for Arctic algal beds and similar to that reported for temperate regions. Estimated sponge richness at our Antarctic sites highlights diverse sponge assemblages (16–26 taxa) between 5 and 20 m that are typically dominated by macroalgae. Our results suggest that sponge assemblages associated with canopy-forming macroalgae on southern high-latitude reefs are more diverse than previously thought. Keywords: Porifera; sponge–algae interactions; Antarctica; sub-Antarctic; southern high-latitudes. (Published: 9 November 2016) Citation: Polar Research 2016, 35 , 30532, http://dx.doi.org/10.3402/polar.v35.30532
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  • 6
    Publication Date: 2016-10-28
    Description: The Antarctic fur seal ( Arctocephalus gazella ) is a key marine predator in the Southern Ocean, a region that has recently started to show changes as a result of global climate change. Here, carbon ( δ 13 C) and nitrogen ( δ 15 N) stable isotope analyses on whole blood and plasma samples were used to examine the isotopic niche of lactating female Antarctic fur seals. Using recently developed Bayesian approaches to determine changes in isotopic niche, a significant increase in δ 13 C and δ 15 N was found between 1997 and 2015; this change occurred at an average rate of 0.067‰ ( δ 13 C) and 0.072‰ ( δ 15 N) per year over this period. This suggests that a marked isotopic niche shift has occurred over this period, which very likely corresponds to a shift in diet towards prey at a higher trophic level, such as fish (replacing krill). Although our sampling design prevented us from exploring a seasonal trend in a conclusive manner, our data suggest that concurrent increases in δ 13 C and δ 15 N might occur as the breeding season progresses. At a seasonal scale, an average decrease of −0.7‰ per month (95% confidence interval=[−0.9; −0.6]) in δ 13 C might have occurred, concurrently with an average increase of 1.1‰ per month in δ 15 N. The results of this study constitute the first isotopic assessment for female Antarctic fur seals from Bouvetøya and provide a baseline for the use of this predator species as a sentinel of the marine trophic system in one of the least studied areas within this species’ distributional range. Keywords: Arctocephalus gazella ; krill; predation; Southern Ocean; stable isotopes; trophic relationships. (Published: 27 October 2016) To access the supplementary material for this article, please see the supplementary file in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 31335, http://dx.doi.org/10.3402/polar.v35.31335
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  • 7
    Publication Date: 2016-10-28
    Description: Our study makes use of a fortuitous oceanographic data set collected around the remote sub-Antarctic island of Bouvetøya by a conductivity–temperature–depth recorder (CTD) integrated with a satellite-relayed data logger deployed on an adult female southern elephant seal ( Mirounga leonina ) to describe the seasonal evolution of the western shelf waters. The instrumented seal remained in waters over the shelf for 259 days, collecting an average of 2.6 (±0.06) CTD profiles per day, providing hydrographic data encompassing the late austral summer and the entire winter. These data document the thermal stratification of the upper water layer due to summer surface heating of the previous year’s Antarctic Surface Water, giving way to a cold subsurface layer at about 100 m as the austral winter progressed, with a concomitant increase in salinity of the upper layer. Upper Circumpolar Deep Water was detected at a depth of approximately 200 m along the western shelf of Bouvetøya throughout the year. These oceanographic data represent the only seasonal time series for this region and the second such animal–instrument oceanographic time series in the sub-Antarctic domain of the Southern Ocean. Keywords: Biotelemetry; diving; elephant seal; oceanography; marine predators; CTD-SRDL. (Published: 27 October 2016) To access the supplementary material for this article, please see supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 28278, http://dx.doi.org/10.3402/polar.v35.28278
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  • 8
    Publication Date: 2016-10-27
    Description: No abstract available. (Published: 26 October 2016) Citation: Polar Research 2016, 35 , 33648,http://dx.doi.org/10.3402/polar.v35.33648
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  • 9
    Publication Date: 2016-10-27
    Description: Intraspecific and non-obligate brood parasitism and nest takeover is well documented in common eiders ( Somateria mollissima borealis ) nesting in the Arctic. However, we report the takeover of a long-tailed duck ( Clangula hyemalis ) nest by a female common eider on Nasaruvaalik Island, Nunavut, Canada. The high nesting density due to limited habitat in the region may have contributed to this seemingly risky behaviour, which provides no clear benefits to the eider. Keywords: Nest takeover; sea ducks; Somateria mollissima ; Clangula hyemalis ; High Arctic; limited habitat. (Published: 26 October 2016) Citation: Polar Research 2016, 35 , 32414, http://dx.doi.org/10.3402/polar.v35.32414
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  • 10
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    Norwegian Polar Institute
    Publication Date: 2016-10-14
    Description: No abstract available. (Published: 9 May 2016) Citation: Polar Research 2016, 35 , 31998,http://dx.doi.org/10.3402/polar.v35.31998
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