https://polarresearch.net/index.php/polar/issue/feed Polar Research 2021-01-22T05:14:36-08:00 Helle V. Goldman helle.goldman@npolar.no 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> https://polarresearch.net/index.php/polar/article/view/3377 Subglacial discharge weakens the stability of the Ross Ice Shelf around the grounding line 2021-01-22T05:14:36-08:00 Yan Li liyan@asch.whigg.ac.cn Hongling Shi hlshi@asch.whigg.ac.cn Yang Lu luyang@asch.whigg.ac.cn Zizhan Zhang zzhang@asch.whigg.ac.cn Hui Xi xihui@asch.whigg.ac.cn <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 https://polarresearch.net/index.php/polar/article/view/5283 Organic carbon and microbiome in tundra and forest–tundra permafrost soils, southern Yamal, Russia 2021-01-08T03:02:07-08:00 Ivan Alekseev alekseevivan95@gmail.com Aleksei Zverev azver.bio@gmail.com Evgeny Abakumov e_abakumov@gmail.com <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