Polar Research 2019-06-16T05:17:12-07:00 Helle V. Goldman Open Journal Systems <p><em>Polar Research</em>&nbsp;is the international, peer-reviewed journal of the&nbsp;<strong><a href="">Norwegian Polar Institute</a></strong>, Norway's central institution for research, environmental monitoring and mapping of the polar regions.&nbsp;</p> Seasonal dynamics of the marine CO<sub>2</sub> system in Adventfjorden, a west Spitsbergen fjord 2019-06-16T05:17:02-07:00 Ylva Ericson Melissa Chierici Eva Falck Agneta Fransson Elizabeth Jones Svein Kristiansen <p>Time series of the marine CO<sub>2</sub>&nbsp;system and related parameters at the IsA Station, by Adventfjorden, Svalbard, were investigated between March 2015 and November 2017. The physical and biogeochemical processes that govern changes in total alkalinity (TA), total dissolved inorganic carbon (DIC) and the saturation state of the calcium carbonate mineral aragonite (Ω<sub>Ar</sub>) were assessed on a monthly timescale. The major driver for TA and DIC was changes in salinity, caused by river runoff, mixing and advection. This accounted for 77 and 45%, respectively, of the overall variability. It contributed minimally to the variability in Ω<sub>Ar</sub>&nbsp;(5%); instead, biological activity was responsible for 60% of the monthly variations. For DIC, the biological activity was also important, contributing 44%. The monthly effect of air–sea CO<sub>2</sub>&nbsp;fluxes accounted for 11 and 15% of the total changes in DIC and Ω<sub>Ar</sub>, respectively. Net community production (NCP) during the productive season ranged between 65 and 85 g C m<sup>−2</sup>, depending on the year and the presence of either Arctic water or transformed Atlantic water (TAW). The annual NCP as estimated from DIC consumption was 34 g C m<sup>−2</sup>&nbsp;yr<sup>−1</sup>&nbsp;in 2016, which was opposite in direction but similar in magnitude to the integrated annual air–sea CO<sub>2</sub>&nbsp;flux (i.e., uptake of carbon from the atmosphere) of −29 g C m<sup>−2</sup>&nbsp;yr<sup>−1</sup>&nbsp;for the same year. The results showed that increased intrusions of TAW into Adventfjorden in the future could possibly lower the NCP, with the potential to reduce the CO<sub>2</sub>buffer capacity and Ω<sub>Ar</sub>&nbsp;over the summer season.</p> 2019-06-11T09:20:34-07:00 ##submission.copyrightStatement## Well drilling in permafrost regions: dynamics of the thawed zone 2019-06-16T05:17:05-07:00 Lev V. Eppelbaum Izzy M. Kutasov <p>In the cold regions, warm mud is usually used to drill deep wells. This mud causes formation thawing around wells, and as a rule is an uncertain parameter. For frozen soils, ice serves as a cementing material, so the strength of frozen soils is significantly reduced at the ice–water transition. If the thawing soil cannot withstand the load of overlying layers, consolidation will take place, and the corresponding settlement can cause significant surface shifts. Therefore, for long-term drilling or oil/gas production, the radius of thawing should be estimated to predict platform stability and the integrity of the well. It is known that physical properties of formations are drastically changed at the thawing–freezing transition. When interpreting geophysical logs, it is therefore important to know the radius of thawing and its dynamics during drilling and shut-in periods. We have shown earlier that for a cylindrical system the position of the phase interface in the Stefan problem can be approximated through two functions: one function determines the position of the melting-temperature isotherm in the problem without phase transitions, and the second function does not depend on time. For the drilling period, we will use this approach to estimate the radius of thawing. For the shut-in period, we will utilize an empirical equation based on the results of numerical modelling.</p> 2019-06-05T00:00:00-07:00 ##submission.copyrightStatement## Dynamics and persistence of rabies in the Arctic 2019-06-16T05:17:03-07:00 Audrey Simon Olivia Tardy Amy Hurford Nicolas Lecomte Denise Bélanger Patrick Leighton <p>Rabies is a major issue for human and animal health in the Arctic, yet little is known about its epidemiology. In particular, there is an ongoing debate regarding how Arctic rabies persists in its primary reservoir host, the Arctic fox (<em>Vulpes lagopus</em>), which exists in the ecosystem at very low population densities. To shed light on the mechanisms of rabies persistence in the Arctic, we built a susceptible–exposed–infectious–recovered (SEIR) epidemiological model of rabies virus transmission in an Arctic fox population interacting with red foxes (<em>Vulpes vulpes</em>), a rabies host that is increasingly present in the Arctic. The model suggests that rabies cannot be maintained in resource-poor areas of the Arctic, characterized by low Arctic fox density, even in the presence of continuous reintroduction of the virus by infected Arctic foxes from neighbouring regions. However, in populations of relatively high Arctic fox density, rabies persists under conditions of higher transmission rate, prolonged infectious period and for a broad range of incubation periods. Introducing the strong cyclical dynamics of Arctic prey availability makes simulated rabies outbreaks less regular but more intense, with an onset that does not neatly track peaks in Arctic fox density. Finally, interaction between Arctic and red foxes increases the frequency and/or the intensity of rabies outbreaks in the Arctic fox population. Our work suggests that disruption of prey cycles and increasing interactions between Arctic and red foxes due to climate change and northern development may significantly change the epidemiology of rabies across the Arctic.</p> 2019-06-05T00:00:00-07:00 ##submission.copyrightStatement## A nematode in the mist: <em>Scottnema lindsayae</em> is the only soil metazoan in remote Antarctic deserts, at greater densities with altitude 2019-06-16T05:17:05-07:00 Krzysztof Zawierucha Craig J. Marshall David Wharton Karel Janko <p>A decrease in biodiversity and density of terrestrial organisms with increasing altitude and latitude is a well-known ecogeographical pattern. However, studies of these trends are often taxonomically-biased toward well-known organisms and especially those with relatively large bodies, and environmental variability at the local scale may perturb these general effects. Here, we focus on understudied organisms—soil invertebrates—in Antarctic deserts, which are among the driest and coldest places on Earth. We sampled two remote Antarctic sites in the Darwin Glacier area and established an altitudinal gradient running from 210 to 836 m a.s.l. We measured soil geochemistry and organic matter content and linked these parameters with the presence of soil invertebrates. We found three general outcomes, two of which are consistent with general assumptions: (a) the hostile climatic condition of the Darwin Glacier region supports an extremely low diversity of soil metazoans represented by a single nematode species—<em>Scottnema lindsayae</em>; (b) soil geochemistry is the main factor influencing distribution of nematodes at the local scale. Contrary to our expectations, a positive correlation was found between nematode density and altitude. This last observation could be explained by an additional effect of soil moisture as we found this increased with altitude and may be caused by orographic clouds, which are present in this region. To the best of our knowledge such effects have been described in tropical and temperate regions. Potential effect of orographic clouds on soil properties in polar deserts may be a fruitful area of ecological research on soil fauna.</p> 2019-05-07T00:00:00-07:00 ##submission.copyrightStatement## Freshwater input to the Arctic fjord Hornsund (Svalbard) 2019-06-16T05:17:05-07:00 Małgorzata Błaszczyk Dariusz Ignatiuk Aleksander Uszczyk Katarzyna Cielecka-Nowak Mariusz Grabiec Jacek A. Jania Mateusz Moskalik Waldemar Walczowski <p>Glaciers draining to the Hornsund basin (southern Spitsbergen, Svalbard) have experienced a significant retreat and mass volume loss over the last decades, increasing the input of freshwater into the fjord. An increase in freshwater input can influence fjord hydrology, hydrodynamics, sediment flux and biota, especially in a changing climate. Here, we describe the sources of freshwater supply to the fjord based on glaciological and meteorological data from the period 2006 to 2015. The average freshwater input from land to the Hornsund bay is calculated as 2517 ± 82 Mt a<sup>−1</sup>, with main contributions from glacier meltwater runoff (986 Mt a<sup>−1</sup>; 39%) and frontal ablation of tidewater glaciers (634 Mt a<sup>−1</sup>; 25%). Tidewater glaciers in Hornsund lose ca. 40% of their mass by frontal ablation. The terminus retreat component accounts for ca. 30% of the mass loss by frontal ablation, but it can vary between 17% and 44% depending on oceanological, meteorological and geomorphological factors. The contribution of the total precipitation over land excluding winter snowfall (520 Mt a<sup>−1</sup>), total precipitation over the fjord area (180 Mt a<sup>−1</sup>) and melting of the snow cover over unglaciated areas (197 Mt a<sup>−1</sup>) to the total freshwater input appear to be small: 21%, 7% and 8%, respectively.</p> 2019-04-16T11:01:27-07:00 ##submission.copyrightStatement## Groundwater discharge to the western Antarctic coastal ocean 2019-06-16T05:17:06-07:00 Kimberly A. Null D. Reide Corbett Jared Crenshaw Richard N. Peterson Leigha E. Peterson W. Berry Lyons <p>Submarine groundwater discharge (SGD) measurements have been limited along the Antarctic coast, although groundwater discharge is becoming recognized as an important process in the Antarctic. Quantifying this meltwater pathway is important for hydrologic budgets, ice mass balances and solute delivery to the coastal ocean. Here, we estimate the combined discharge of subglacial and submarine groundwater to the Antarctic coastal ocean. SGD, including subglacial and submarine groundwater, is quantified along the WAP at the Marr Glacier terminus using the activities of naturally occurring radium isotopes (<sup>223</sup>Ra,&nbsp;<sup>224</sup>Ra). Estimated SGD fluxes from a&nbsp;<sup>224</sup>Ra mass balance ranged from (0.41 ± 0.14)×10<sup>4</sup>&nbsp;and (8.2 ± 2.3)×10<sup>4</sup>m<sup>3</sup>&nbsp;d<sup>−1</sup>. Using a salinity mass balance, we estimate SGD contributes up to 32% of the total freshwater to the coastal environment near Palmer Station. This study suggests that a large portion of the melting glacier may be infiltrating into the bedrock and being discharged to coastal waters along the WAP. Meltwater infiltrating as groundwater at glacier termini is an important solute delivery mechanism to the nearshore environment that can influence biological productivity. More importantly, quantifying this meltwater pathway may be worthy of attention when predicting future impacts of climate change on retreat of tidewater glaciers.</p> 2019-04-04T03:46:43-07:00 ##submission.copyrightStatement## Distribution and fluxes of dissolved organic carbon in the Arctic Ocean 2019-06-16T05:17:07-07:00 Alexander Vetrov Evgeny Romankevich <p>Dissolved organic carbon, from marine biota excretions and decomposing detritus, is one of the main components of the carbon cycle in the ocean. In this study, an attempt was made to construct maps of the distribution and fluxes of DOC in the Arctic Ocean and the exchanges with the Pacific and Atlantic Oceans. Because of the limited data available a multiple linear regression technique was performed to identify significant relationships between DOC (2200 samples) and hydrologic parameters (temperature and salinity), as well as depth, horizon, latitude and offshore distance. Mapping of the DOC distribution and its fluxes was carried out at 38 horizons from 5 to 4150 m depth (resolution 1°×1°). Data on temperature, salinity and meridional and zonal components of current velocities were obtained from the Ocean Re-Analysis System 4 (ORAS4) database. All these parameters were averaged for the June–October period, the season of water sampling. The import of DOC in the Arctic Ocean is estimated to be 206 ± 17Tg C yr<sup>−1</sup>, and the export is 194 ± 23Tg C yr<sup>−1</sup>, so the import–export is balanced within the errors.</p> 2019-03-29T07:00:29-07:00 ##submission.copyrightStatement## Diversity and community structure of bacterioplankton in surface waters off the northern tip of the Antarctic Peninsula 2019-06-16T05:17:08-07:00 Shunan Cao Jianfeng He Fang Zhang Ling Lin Yuan Gao Qiming Zhou <p>Global climate change is significantly affecting marine life off the northern tip of the Antarctic Peninsula, but little is known about microbial ecology in this area. The main goal of this study was to investigate the bacterioplankton community structure in surface waters using pyrosequencing and to determine factors influencing this community. Pelagibacterales and Rhodobacterales (Alphaproteobacteria), Oceanospirillales and Alteromonadales (Gammaproteobacteria), and Flavobacteriales (Bacteroidetes) were the core taxa in our samples, and the five most relatively abundant genera were&nbsp;<em>Pelagibacter</em>,&nbsp;<em>Polaribacter</em>,&nbsp;<em>Octadecabacter</em>, group HTCC2207 and&nbsp;<em>Sulfitobacter</em>. Although nutrients and chlorophyll&nbsp;<em>a</em>&nbsp;(chl&nbsp;<em>a</em>) contributed more to bacterioplankton community structure than water masses or depth, only 30.39% of the variance could be explained by the investigated environmental factors, as revealed by RDA and pRDA. No significant difference with respect to nutrients and chl&nbsp;<em>a</em>&nbsp;was observed among water masses or depth, as indicated by ANOVA. Furthermore, significant correlations among the dominant bacterial genera were more common than correlations between dominant genera and environmental factors, as revealed by Spearman analysis. We conclude that nutrients and chl&nbsp;<em>a</em>&nbsp;become homogeneous and that interpopulation interactions may have a central role in influencing the bacterial community structure in surface waters off the northern tip of the Antarctic Peninsula during the summer.</p> 2019-03-21T07:26:10-07:00 ##submission.copyrightStatement## Summer habitat selection by ringed seals (<em>Pusa hispida</em>) in the drifting sea ice of the northern Barents Sea 2019-06-16T05:17:09-07:00 Karen Lone Charmain D. Hamilton Jon Aars Christian Lydersen Kit M. Kovacs <p>Ringed seals are a central component of the Arctic ecosystem; they have a circumpolar distribution and are both important predators of lower trophic animals (invertebrates and fishes) and prey for polar bears and coastal human populations. They depend on sea ice for reproduction, moulting and resting, and they consume significant amounts of ice-associated prey. The population of ringed seals in Svalbard, Norway, uses both coastal and offshore habitats, the latter being important during seasonal migrations undertaken by some animals, mostly juveniles. This study examined habitat preferences of 18 satellite-tracked ringed seals (mostly young animals, but also a few adults) during late summer/autumn migrations to the drift ice in the northern Barents Sea. Resource selection functions showed that ringed seals preferred being close to the 50% sea-ice concentration threshold; a 120 km increase in the distance to the 50% sea-ice concentration threshold halved the probability of selection of a given area. In addition, higher sea-ice concentrations (80–100%) were between 1.4 and 2.2 times as likely to be selected as lower sea-ice concentrations or open water. Ringed seals use the marginal ice zone of the Barents Sea during summer/autumn. This offshore habitat has shifted northward during recent decades, which is likely causing negative effects on ringed seals by increasing the energetic cost of offshore migrations.</p> 2019-03-13T06:05:17-07:00 ##submission.copyrightStatement## A multi-year study of narwhal occurrence in the western Fram Strait—detected via passive acoustic monitoring 2019-06-16T05:17:09-07:00 Heidi Ahonen Kathleen M. Stafford Christian Lydersen Laura de Steur Kit M. Kovacs <p>Passive acoustic monitoring (PAM) has proven to be an efficient method for studying vocally active marine mammals in areas that are difficult to access on a year-round basis. In this study, a PAM recorder was deployed on an oceanographic mooring in western Fram Strait (78°50'N, 5°W) to record the acoustic presence of narwhals (<em>Monodon monoceros</em>) over a 3-yr period. Acoustic data were recorded for 14–17 min at the start of each hour from 25 September 2010 to 26 August 2011, from 2 September 2012 to 11 April 2013 and from 8 September 2013 to 27 April 2014. Pulsed and tonal signals, as well as echolocation clicks, were detected throughout the recording periods, demonstrating that this species is present in this region throughout the year. Generalized linear mixed-effect models showed a negative correlation between the acoustic presence of narwhals and very dense sea-ice cover (≥90%). Surprisingly, a positive correlation was found between the acoustic presence of narwhals and the presence of warm Atlantic Water in the area. Available data suggest that there might be a unique stock of narwhals in the Eurasian sector of the Atlantic Arctic that do not exhibit the “traditional” narwhal pattern of seasonal migration between coastal summering areas and offshore wintering grounds, but rather remain resident year-round in deep, offshore waters.</p> 2019-03-06T03:23:37-08:00 ##submission.copyrightStatement## <em>Pseudolamarckina pseudorjasanensis </em>Dain, 1967 (Foraminifera) as a Kimmeridgian marker species and its significance for biostratigraphy, palaeoecology and palaeobiogeography 2019-06-16T05:17:10-07:00 Clémentine Peggy Anne-Marie Colpaert Boris Leonidovich Nikitenko <p>This study presents a taxonomical review of the species&nbsp;<em>Pseudolamarckina pseudorjasanensis</em>&nbsp;Dain, 1967 collected at different sampling levels from the central and northern parts of European Russia and from Western Siberia. Morphological and biometrical analyses show that&nbsp;<em>P. pseudorjasanensis</em>&nbsp;is characterized by wide intraspecific variabilities and may encompass various previously described Kimmeridgian species of the genus&nbsp;<em>Pseudolamarckina</em>. The first appearance of&nbsp;<em>P. pseudorjasanensis</em>&nbsp;is recorded from the latest Early Kimmeridgian of sub-Mediterranean to Arctic regions. Furthermore,&nbsp;<em>P. pseudorjasanensis</em>&nbsp;appears to be the marker species of the foraminiferal JF41 Zone in Kimmeridgian sections of sub-boreal, boreal and Arctic regions. This JF41 Zone is particularly significant for interregional correlations. Finally,&nbsp;<em>P. pseudorjasanensis</em>&nbsp;was widespread across the Kimmeridgian basins of the Northern Hemisphere and was associated with environments predominantly located in the middle sublittoral zone.</p> 2019-03-05T02:45:35-08:00 ##submission.copyrightStatement## Incomplete degradation of lichen usnic acid and atranorin in Svalbard reindeer (<em>Rangifer tarandus platyrhynchus</em>) 2019-06-16T05:17:12-07:00 Michał Hubert Węgrzyn Paulina Wietrzyk-Pełka Agnieszka Galanty Beata Cykowska-Marzencka Monica Alterskjær Sundset <p>Previous studies of Eurasian tundra reindeer (<em>Rangifer tarandus tarandus</em>) in Norway indicate that their rumen microbiota play a key role in degrading lichen secondary metabolites. We investigated the presence of usnic acid and atranorin in faecal samples from Svalbard reindeer&nbsp;<em>(R. tarandus platyrhynchus</em>). Samples were collected in Bolterdalen valley together with vegetation samples from the study site. The mesic tundra in this area was dominated by vascular plants (59% of vegetation cover). Bryophytes (16%) and lichens (25%) were also present. Qualitative and quantitative analyses of usnic acid and atranorin in lichen and faeces samples were performed using high-performance liquid chromatography. Contents of atranorin averaged 12.49 ± 0.41 mg g<sup>–1</sup>in the thalli of&nbsp;<em>Stereocaulon alpinum</em>, while the average level of usnic acid was lowest in&nbsp;<em>Cladonia mitis</em>&nbsp;(12.75 ± 2.86 mg g<sup>–1</sup>) and highest in&nbsp;<em>Flavocetraria cucullata</em>&nbsp;(34.87 ± 0.47 mg g<sup>–1</sup>). Atranorin and usnic acid were detected in the faecal samples, averaging 0.41 ± 0.53 and 0.74 ± 1.11 (mean ± SD) mg g<sup>–1</sup>&nbsp;dry matter, respectively. The presence of lichen secondary compounds in faeces from Svalbard reindeer shows that lichens are indeed included in their diet, although probably in small amounts because of depleted pastures. Contrary to previous findings in reindeer on mainland Norway, atranorin and usnic acid are not completely degraded or absorbed in Svalbard reindeer. To elucidate the mechanisms behind detoxification of lichen secondary compounds in reindeer, more research is needed on their respective rumen microbiomes and digestive enzymes.</p> 2019-01-22T03:32:48-08:00 ##submission.copyrightStatement## A note on digital elevation model smoothing and driving stresses 2019-06-16T05:17:07-07:00 Felicity S. McCormack Jason L. Roberts Lenneke M. Jong Duncan A. Young Lucas H. Beem <p>Ice-flow fields, including the driving stress, provide important information on the current state and evolution of Antarctic and Greenland ice-sheet dynamics. However, computation of flow fields from continent-scale DEMs requires the use of smoothing functions and scales, the choice of which can be ad hoc. This study evaluates smoothing functions and scales for robust calculations of driving stress from Antarctic DEMs. Our approach compares a variety of filters and scales for their capacity to minimize the residual between predicted and observed flow direction fields. We find that a spatially varying triangular filter with a width of 8–10 ice thicknesses provides the closest match between the observed and predicted flow direction fields. We use the predicted flow direction fields to highlight artefacts in observed Antarctic velocities, demonstrating that comparison of multiple observational data sets has utility for quality control of continent-scale data sets.</p> 2019-03-28T07:19:27-07:00 ##submission.copyrightStatement## First evidence of a tetrapod footprint from the Triassic of northern Victoria Land, Antarctica 2019-06-16T05:17:11-07:00 Thomas Mörs Grzegorz Niedźwiedzki Laura Crispini Andreas Läufer Benjamin Bomfleur <p>Here, we report on a tetrapod footprint from the Transantarctic Basin in the far north of Victoria Land, which marks the first record of terrestrial vertebrates for this region. The single specimen derives from a previously unknown lithological unit of Middle or Late Triassic age of the Beacon Supergroup in the Helliwell Hills in the central Rennick Glacier area. It differs in both size and morphology clearly from Middle Triassic trackway types from the upper Fremouw Formation of the Queen Alexandra Range in southern Victoria Land, and likely represents a primitive amniote, procolophonid or therapsid. The footprint is the third evidence of fossil vertebrate trackways in Antarctica.</p> 2019-02-14T00:00:00-08:00 ##submission.copyrightStatement## Review of <em>Four Antarctic years in the South Orkney Islands: an annotated translation of Cuatro años en las Orcadas del Sur</em>, by Jose Manuel Moneta (2017). London: Bernard Quaritch. 440 pp. ISBN 978-0-9955192-0-6. 2019-06-16T05:17:10-07:00 Adrian Howkins <p>(No abstract available)</p> 2019-03-05T00:00:00-08:00 ##submission.copyrightStatement## Review of <em>The spectral Arctic: a history of dreams and ghosts in polar exploration</em> by Shane McCorristine (2018). London: University College London Press. 265 pp. ISBN 978-1-78735-246-9. 2019-06-16T05:17:12-07:00 Dianne Chisholm <p>(No abstract available)</p> 2019-01-21T04:51:24-08:00 ##submission.copyrightStatement##