Polar Research 2021-02-17T10:12:41-08:00 Helle V. Goldman Open Journal Systems <p><em>Polar Research</em> is the international, peer-reviewed journal of the Norwegian Polar Institute. The scope of&nbsp;<em>Polar Research</em>&nbsp;encompasses research in all scientific disciplines relevant to the polar regions. These include, but are not limited to, the subfields of biology, ecology, geology, oceanography, glaciology and atmospheric science. Submissions from the social sciences and those focusing on polar management and policy issues are welcome. Contributions about Antarctica are particularly encouraged.</p> Inferring population structure and genetic diversity of the invasive alien Nootka lupin in Iceland 2021-02-17T10:12:41-08:00 Jakub Skorupski Magdalena Szenejko Martyna Gruba-Tabaka Przemysław Śmietana Remigiusz Panicz <p>Polar and subpolar regions are known for their particular vulnerability and sensitivity to the detrimental effects of non-indigenous species, which is well exemplified by the Nootka lupin (<em>Lupinus nootkatensis</em>) spread in Iceland. Since understanding the population and ecological genetics of invasive alien species offers hope for counteracting harmful biological invasions, the objective of the present study was to investigate interspecific variation in&nbsp;<em>L. nootkatensis</em>&nbsp;in Iceland in relation to a native population in Alaska. Moreover, we aimed to assess whether internal transcribed spacer 2 (ITS2) has sufficient phylogenetic applicability for a large-scale screening of the genetic diversity of a non-indigenous population of this species. This study, which is the first attempt to investigate the genetic diversity of the Nootka lupin in Iceland, included plant samples from eight locations in Iceland and one in Alaska. The analyses included genotyping by sequencing of the 417-nucleotide fragment of the 5.8S ribosomal RNA, ITS2 and part of the large subunit ribosomal RNA (GenBank MT026578-MT026580, MT077004). The main findings showed the presence of five previously unexplained single-nucleotide polymorphisms (SNPs); however, their discriminatory power for Icelandic populations was relatively low, since polymorphism information content (PIC) values ranged from 0.0182 to 0.0526, with average heterozygosity 0.0296. Concomitantly, analysis of multilocus genotypes (MLG) revealed sufficient differences in MLGs variants and their frequency to form genotypic patterns unique for Alaskan and Icelandic populations, revealing an internal genetic structure of the studied group. The proposed SNP panel needs to be supplemented with other nuclear and organellar markers.</p> 2021-02-17T10:10:42-08:00 Copyright (c) 2021 Jakub Skorupski, Magdalena Szenejko, Martyna Gruba-Tabaka, Przemysław Śmietana, Remigiusz Panicz Distribution and habitat characteristics of pinnipeds and polar bears in the Svalbard Archipelago, 2005–2018 2021-02-09T04:53:44-08:00 Olof Bengtsson Charmain D. Hamilton Christian Lydersen Magnus Andersen Kit M. Kovacs <p>This study presents comprehensive mapping of the current distribution of pinnipeds and polar bears (<em>Ursus maritimus</em>) around Svalbard based on a regional marine mammal sightings programme and explores time-trends (2005–2018). Walruses (<em>Odobenus rosmarus</em>) were observed with high frequency and in high numbers around previously identified haul-out sites. At-sea walruses were seen close to the coast in shallow waters. Ringed seals (<em>Pusa hispida</em>) were observed in coastal areas throughout Svalbard, often in association with tidewater glacier fronts. There was no increase in the mean latitude for ringed seal observations, but there was an increased frequency of observations at around 82°N, which reflects their following a northward shift in the ice edge during summer foraging trips. Bearded seals (<em>Erignathus barbatus</em>) were observed frequently in north-western Spitsbergen and shared many habitat features with ringed seals. There was a slight increase in the mean latitude of bearded seal observations and a decreased frequency of observation in the southern parts of the archipelago, suggesting that this species might be shifting its distribution. Harbour seal (<em>Phoca vitulina</em>) observations within fjords have increased, likely as a consequence of increased inflow of Atlantic water into west coast fjords. Harp seals (<em>Pagophilus groenlandicus</em>) were observed with high frequency north of Svalbard. Hooded seals (<em>Cystophora cristata</em>) were observed only rarely. Polar bears were reported most frequently, undoubtedly as a result of an effort bias favouring this species. In spite of biases, citizen-based observations are useful for assessing broad distributional patterns of marine mammals through time.</p> 2021-02-04T04:08:06-08:00 Copyright (c) 2021 Olof Bengtsson, Charmain D. Hamilton, Christian Lydersen, Magnus Andersen, Kit M. Kovacs Subglacial discharge weakens the stability of the Ross Ice Shelf around the grounding line 2021-01-22T05:14:36-08:00 Yan Li Hongling Shi Yang Lu Zizhan Zhang Hui Xi <p>In this paper, we examine potential impact of discharge in Subglacial Lake Engelhardt, West Antarctica, on the stability of the Ross Ice Shelf around the grounding line by combining satellite altimetry and remote sensing images. According to satellite altimetry data from the Ice, Cloud and Land Elevation Satellite (ICESat; 2003–06), Subglacial Lake Engelhardt (SLE) discharged ca. 1.91 ± 0.04 km<sup>3</sup>&nbsp;of water into the downstream region. The ice-surface record derived from ICESat (2006–09) and CryoSat-2 (2011–17) data shows that the lake gained ca. 2.09 ± 0.05 km<sup>3</sup>&nbsp;of water during the refilling event following the drainage event, taking three times as much time to reach the previous water level before the discharge; the calculation demonstrates that water input from an upstream lake is unable to sustain water increase in SLE, indicating that the subglacial, hydrologic system and groundwater flow could have contributed to water increase in SLE via hydrologic networks. Satellite images captured surface depressions and crevasses at the drainage outlet point of hydrologic networks around the grounding line; satellite altimetry data show that the ice surface there is still depressing even though the subglacial discharge has finished, potentially reflecting the long-term impact of subglacial discharge on the stability of the immediate Ross Ice Shelf around the grounding line.</p> 2021-01-22T05:13:18-08:00 Copyright (c) 2021 Yan Li, Hongling Shi, Yang Lu, Zizhan Zhang, Hui Xi Organic carbon and microbiome in tundra and forest–tundra permafrost soils, southern Yamal, Russia 2021-01-08T03:02:07-08:00 Ivan Alekseev Aleksei Zverev Evgeny Abakumov <p>Permafrost soils differ significantly from other soils because they serve as a huge reservoir for organic carbon accumulated during the Quaternary Period, which is at risk of being released as the Arctic warms. This study aimed to characterize existing carbon pools, delineate possible mineralization risks of soil organic matter and assess microbial communities in the tundra and forest–tundra permafrost soils of the southern Yamal region of Russia. The profile distribution of carbon, nitrogen and the C:N ratio showed non-gradual changes with depth due to the manifestation of cryopedogenesis in soil profiles, which lead to cryogenic mass transfer. Mean carbon stocks for the study area were 7.85 ± 2.24 kg m<sup>−2</sup>&nbsp;(0–10 cm layer), 14.97 ± 5.53 kg m<sup>−2</sup>&nbsp;(0–30 cm) and 23.99 ± 8.00 kg m<sup>−2</sup>&nbsp;(0–100 cm). The analysis of the humus type revealed a predominance of fulvic type and low-molecular-weight fragments in the fulvic acid fraction, which indicates high mineralization risk of humic substances under Arctic warming conditions. The taxonomic analysis of soil microbiomes revealed 48 bacterial and archaeal phyla, among which proteobacteria (27%) and actinobacteria (20%) were predominant. The pH range and nitrogen accumulation were the main environmental determinants of microbial community diversity and composition in the studied soils.</p> 2021-01-08T02:56:31-08:00 Copyright (c) 2021 Ivan Alekseev, Aleksei Zverev, Evgeny Abakumov