Description: Recent ground temperature records from the 100-m-deep borehole near the Tarfala Research Station in northern Sweden reveal that permafrost is warming at a pace consistent with the rate of measured air temperature increase at the site. Here we investigate whether air temperature increase is the main driver of the observed change in the permafrost thermal regime using a non-isothermal hydrogeological numerical model for partially frozen ground. The local site is investigated with different ground surface temperature scenarios representing different integrated effects of surficial heat attenuation processes. Results indicate that despite a short-term sensitivity to heat attenuation processes including snow conditions, the main driver of change in the permafrost thermal regime during the past decade is warming air temperatures. Additionally, the approach used here is shown to be particularly pertinent for modelling warming trends, despite limited prior knowledge of site-specific conditions and geological properties. Understanding the main driving mechanisms of changing permafrost is useful for assessing the suitability of borehole temperature records as proxies for past environmental conditions as well as for modelling possible future climatic impacts. Keywords: Permafrost; warming ground; PACE borehole; numerical modelling; climate change. (Published: 29 September 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 28978, http://dx.doi.org/10.3402/polar.v35.28978

Description: No abstract available. (Published: 27 September 2016) Citation: Polar Research 2016, 35 , 33308,http://dx.doi.org/10.3402/polar.v35.33308

Description: Ice-rich permafrost coasts often undergo rapid erosion, which results in land loss and release of considerable amounts of sediment, organic carbon and nutrients, impacting the near-shore ecosystems. Because of the lack of volumetric erosion data, Arctic coastal erosion studies typically report on planimetric erosion. Our aim is to explore the relationship between planimetric and volumetric coastal erosion measurements and to update the coastal erosion rates on Herschel Island in the Canadian Arctic. We used high-resolution digital elevation models to compute sediment release and compare volumetric data to planimetric estimations of coastline movements digitized from satellite imagery. Our results show that volumetric erosion is locally less variable and likely corresponds better with environmental forcing than planimetric erosion. Average sediment release volumes are in the same range as sediment release volumes calculated from coastline movements combined with cliff height. However, the differences between these estimates are significant for small coastal sections. We attribute the differences between planimetric and volumetric coastal erosion measurements to mass wasting, which is abundant along the coasts of Herschel Island. The average recorded coastline retreat on Herschel Island was 0.68 m a −1 for the period 2000–2011. Erosion rates increased by more than 50% in comparison with the period 1970–2000, which is in accordance with a recently observed increase along the Alaskan Beaufort Sea. The estimated annual sediment release was 28.2 m 3 m −1 with resulting fluxes of 590 kg C m −1 and 104 kg N m −1 . Keywords: Coastal erosion; LiDAR; carbon fluxes; mass wasting; landslides; digital elevation model. (Published: 23 September 2016) To access the supplementary material for this article, please see Supplementary files under Article Tools online. Citation: Polar Research 2016, 35 , 30313, http://dx.doi.org/10.3402/polar.v35.30313

Description: Sea-ice outflow from the Laptev Sea is of considerable importance in maintaining the Arctic Ocean sea-ice budget. In this study, a method exclusively using multiple satellite observations is used to calculate sea-ice volume flux across the eastern boundary (EB) and northern boundary (NB) of the Laptev Sea during the October–November and February–March or March–April periods (corresponding to the ICESat autumn and winter campaigns) between 2003 and 2008. Seasonally, the mean total ice volume flux (i.e., NB+EB) over the investigated autumn period (1.96 km 3 /day) is less than that over the winter period (2.57 km 3 /day). On the other hand, the large standard deviations of the total volume flux, 3.45 and 0.91 km 3 /day for the autumn and winter campaigns, indicate significant interannual fluctuations in the calculated quantities. A statistically significant ( P 〉0.99) positive correlation, R =0.88 (or 0.81), is obtained between volume flux across the EB (or NB) and mean ice-drift speed over the boundary for the considered 11 ICESat campaigns. In addition, statistics show that a large fraction of the variability in volume flux across the NB over the 11 investigated campaigns, roughly 40%, is likely explained by ice thickness variability. On average, flux through the Laptev Sea amounts to approximately one-third of that across Fram Strait during the autumn and winter campaigns. These large contributions of sea ice from the Laptev Sea demonstrate its importance as an ice source, affecting the entire sea-ice mass balance in the Arctic Ocean. Keywords: Mass balance; remote sensing; climate change. (Published: 1 September 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 , 24875, http://dx.doi.org/10.3402/polar.v35.24875

Description: High latitude and altitude floras are characterized by low-statured, small, wind-pollinated plants, which mainly reproduce by self-pollination or asexual reproduction. However, at odds with this are some sub-Antarctic islands that have plant species with giant growth forms and large, brightly coloured flowers which require insect visitation for pollination. The size, colour and shape of the inflorescences and leaves of these megaherbs suggest thermal benefits similar to giant tropical alpine plants of equatorial Africa, South America and Hawaii. We evaluated whether heating occurs in sub-Antarctic megaherbs, and to what extent it is related to environmental variables. We measured leaf and inflorescence temperature in six sub-Antarctic megaherb species on Campbell Island, latitude 52.3°S, New Zealand Biological Region. Using thermal imaging techniques, in combination with measurement of solar radiation, ambient air temperature, wind speed, wind chill and humidity, we assessed environmental influences on leaf and floral heating. We found that leaf and inflorescence temperatures of all megaherbs were higher than simultaneously measured ambient temperatures. Greatest heating was seen in Pleurophyllum speciosum, with observed leaves 9°C higher, and inflorescences nearly 11°C higher, than ambient temperature. Heating was highly correlated with brief, unpredictable periods of solar radiation, and occurred most rapidly in species with hairy, corrugated leaves and darkly pigmented, densely packed inflorescences. This is the first evidence that floral and leaf heating occurs in sub-Antarctic megaherbs, and suggests that leaf hairiness, flower colour and shape could provide thermal benefits like those seen in tropical alpine megaherbs. Keywords: Campbell Island; flower colour; thermal imaging; Pleurophyllum speciosum . (Published: 29 August 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 26030, http://dx.doi.org/10.3402/polar.v35.26030

Description: Most birds preen their feathers with an oily excrete from the uropygial (preen) gland. This oily excrete contains persistent organic pollutants (POPs), which make the preen gland a potential route of depuration of POPs in birds. Black-legged kittiwakes ( Rissa tridactyla ) were studied during two periods of high energy demand: incubation and chick-rearing. A rather high concentration of POPs in preen gland tissue indicates that the preen gland secrete is an excretory pathway for POPs in kittiwakes. The similarity in the POP profile detected in this study of liver, preen gland and feathers suggests that POPs found in the feathers are excreted through the preen gland. The finding also indicates that excretion of POPs through the preen gland is compound unspecific. This qualitative study should be followed up by a new quantitative study to determine the importance of excretion of POPs through the preen gland. Keywords: Feather; organochlorinated pesticides; polychlorinated biphenyls; Rissa tridactyla . (Published: 18 August 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 29651, http://dx.doi.org/10.3402/polar.v35.29651

Description: We analyse surface sediment and its distribution in Flandres Bay, West Antarctic Peninsula, in order to understand modern day sediment dispersal patterns in a fjord with retreating, tidewater glaciers. The surface sediment descriptions of 41 cores are included in this study. The sediment facies described include muddy diatomaceous ooze, diatomaceous mud, pebbly mud, sandy mud and mud, with scattered pebbles present in most samples. In contrast to a traditional conceptual model of glacial sediment distribution in fjords, grain size in Flandres Bay generally coarsens from the inner to outer bay. The smallest grain size sediments were found in the bay head and are interpreted as fine-grained deposits resulting from meltwater plumes and sediment gravity flows occurring close to the glacier front. The middle of the bay is characterized by a high silt percentage, which correlates to diatom-rich sediments. Sediments in the outer bay have a high component of coarse material, which is interpreted as being the result of winnowing from currents moving from the Bellingshausen Sea into the Gerlache Strait. Palaeoenvironmental reconstructions of glacial environments often use grain size as an indicator of proximity to the ice margin. After a detailed analysis of a large number of cores collected in the study area, our findings highlight the variability in sedimentation patterns within a fjord and provide a valuable evidence of the complexity that may occur in the sedimentary record. Keywords: Flandres Bay; Antarctic Peninsula; sediment distribution; grain size. (Published: 12 August 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 25284, http://dx.doi.org/10.3402/polar.v35.25284

Description: Photosynthesis at high latitudes demands efficient strategies of light utilization to maintain algal fitness and performance. The fitness, and physiological adaptation, of a plant or algae species depends in part on the abundance and efficiency of the pigments it can produce to utilize the light resource from its environment. We quantified pigment composition and concentration in six species of the brown macroalgal genus Desmarestia, collected from sub-Antarctic sites (Strait of Magellan, Beagle Channel–Cape Horn Province) and sites on the Antarctic Peninsula and adjacent islands. Sub-Antarctic Desmarestia species exhibited lower concentrations of chlorophyll a , chlorophyll c and fucoxanthin than endemic Antarctic species. Antarctic samples of D. menziesii and D. antarctica collected along a decreasing latitudinal gradient showed spatial and interspecific differences in light-harvesting pigment composition. Our results suggest distinct physiological adjustments in Desmarestia species in response to heterogeneous abiotic environmental conditions. The marine sub-Antarctic and Antarctic ecosystems are characterized by harsh environments (e.g., extreme irradiance, photoperiod, temperature, salinity) to which the physiology of macroalgal species must adapt. Keywords: Macroalgae; Phaeophyceae; photosynthesis; physiology; environmental heterogeneity; Chile. (Published: 4 August 2016) Citation: Polar Research 2016, 35 , 29383,http://dx.doi.org/10.3402/polar.v35.29383

Description: The airship Italia , commanded by General Umberto Nobile, crashed during its return flight from the North Pole in 1928. The cause of the accident was never satisfactorily explained. We present evidence that the crash may have been fatigue-related. Nobile’s memoirs indicate that at the time of the crash he had been awake for at least 72 h. Sleep deprivation impairs multiple aspects of cognitive functioning necessary for exploration missions. Just prior to the crash, Nobile made three command errors, all of which are of types associated with inadequate sleep. First, he ordered a release of lift gas when he should have restarted engines (an example of incorrect data synthesis, with deterioration of divergent thinking); second, he inappropriately ordered the ship above the cloud layer (a deficiency in the assessment of relative risks); and third, he remained above the cloud layer for a prolonged period of time (examples of attention to secondary problems, and calculation problems). We argue that as a result of these three errors, which would not be expected from such an experienced commander, there was no longer enough static lift to maintain level flight when the ship went below the cloud layer. Applying Circadian Performance Simulation Software to the sleep–wake patterns described by Nobile in his memoirs, we found that the predicted performance for someone awake as long as he had been is extremely low. This supports the historical evidence that human fatigue contributed to the crash of the Italia . Keywords: Sleep; Nobile; polar exploration; aviation history; human error; mishap. (Published: 29 July 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 27105, http://dx.doi.org/10.3402/polar.v35.27105 Citation: Polar Research 2016, 35 , 27105, http://dx.doi.org/10.3402/polar.v35.27105 Copyright: © 2016 G.A. Bendrick et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License , permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Published: 29 July 2016 * Correspondence to: Gregg A. Bendrick, Armstrong Flight Research Center, National Aeronautics and Space Administration, PO Box 273, Mailstop 4822, Edwards Air Force Base, CA 93523, USA. E-mail: gregg.a.bendrick@nasa.gov To access the supplementary material for this article, please see the supplementary files under Article Tools, online.  

Description: Daily temperature measurements from six meteorological stations along the coast and fjords of western Spitsbergen have been digitized and quality controlled in a Norwegian, Russian and Polish collaboration. Complete daily data series have been reconstructed back to 1948 for all of the stations. One of the station’s monthly temperature series has previously been extended back to 1898 and is included in this study. The long-term series show large temperature variability on western Spitsbergen with colder periods in the 1910s and 1960s and warmer periods in the 1930s, 1950s and in the 21st century. The most recent years are the warmest ones in the instrumental records. There is a positive and statistically significant trend in the annual times series for all of the stations; however, the strongest warming is seen in winter and spring. For the period 1979–2015, the linear trends range from 1.0 to 1.3°C/decade for the annual series and from 2.0 to 2.3°C/decade in winter. Threshold statistics demonstrate a decrease in the number of cold days per year and an increase in the number of warm days. A decreasing inter-annual variability is observed. In winter, spring and autumn, the stations in the northernmost areas of west Spitsbergen and in the innermost parts of Isfjorden are the coldest ones. In summer, however, the southernmost station is the coldest one. Keywords: Svalbard; Arctic; trends; development; warming; temperature changes. (Published: 29 July 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 29878, http://dx.doi.org/10.3402/polar.v35.29878