Polar Research (E-Journal)
Not a member yet
1388 research outputs found
Sort by
The radiolarian fauna during the Younger Dryas–Holocene transition in Andfjorden, northern Norway
No full textWe report on the changing radiolarian faunas from the Younger Dryas (ca.12.9 calibrated thousands of years BP [cal. Ky BP]) and into the Holocene (ca. 10.3 cal. Ky BP) in the core JM99-1200 from Andfjorden, northern Norway. Temperature reconstructions using both the Q-mode factor analysis and modern analogue technique methods show stable, cold temperatures below ca. 410 cm core depth, followed by abrupt warming into a relatively stable Holocene temperature regime. Age-depth modelling with three different methods gives an age of ca. 11.9–12.0 cal. Ky BP at this core depth, clearly older than the Younger Dryas–Holocene transition at ca. 11.65 cal. Ky BP according to ice core chronology. Considering that the age models may be insufficiently informed in an interval without radiometric dates, it is possible that the base of the Holocene is indeed at 410 cm, as indicated by the radiolarian and other core data. Such a change in the chronology would have implications for previously published work on the JM99-1200 core. Alternatively, the abrupt warming in Andfjorden predated the Younger Dryas–Holocene transition by a few hundred years. A distinct cold pulse at ca. 315–335 cm, or 11.4–11.5 cal. Ky BP is interpreted as the Preboreal Oscillation. The Preboreal Oscillation has not previously been detected in temperature curves based on planktic foraminifera in the same core, indicating that Radiolaria may be a more sensitive temperature indicator in this region
Groundwater discharge to the western Antarctic coastal ocean
No full textSubmarine 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 (223Ra, 224Ra). Estimated SGD fluxes from a 224Ra mass balance ranged from (0.41 ± 0.14)×104 and (8.2 ± 2.3)×104m3 d−1. 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
Review of Svalbard from above, by Bjørn Fossli Johansen, Harald Faste Aas, Anders Skoglund & Oddveig Øien Ørvoll, Tromsø, Norwegian Polar Institute, 2017, 215 pp., hardback, 399 NOK (approximately 51 USD). ISBN 978-82- 7666-410-2
No full text
 
Nutrient uptake controls and limitation dynamics in north-east Greenland streams
No full textPermafrost thaw induced by climate change will cause increased release of nutrients and organic matter from the active layer to Arctic streams and, with increased water temperature, will potentially enhance algal biomass and nutrient uptake. Although essential for accurately predicting the response of Arctic streams to environmental change, knowledge of nutrient release on current Arctic in-stream processing is limited. Addressing this research gap, we quantified nutrient uptake of short-term releases of NO 3 − , PO 4 3- and NH 4 + during peak snowmelt season in five streams of contrasting physiochemical characteristics (from unstable, highly turbid to highly stable, clear-water systems) in north-east Greenland to elucidate the major controls driving nutrient dynamics. Releases were plus or minus acetate to evaluate uptake dynamics with and without a dissolved organic carbon source. To substantiate limiting nutrients to algal biomass, nutrient-diffusing substrates were installed in the five streams for 16 days with NH 4 + , PO 4 3- or NH 4 + + PO 4 3- on organic and inorganic substrates. Observed low uptake rates were due to a combination of low nutrient and DOC concentrations, combined with low water temperature and primary producer biomass, and substantial variation occurred between streams. N was found to be the primary limiting nutrient for biofilm, whilst streams displayed widespread PO 4 3- limitation. This research has important implications for future changes in nutrient processing and export in Arctic streams, which are predicted to include increased nutrient uptake rates due to increased nutrient availability, warmer water temperatures and increased concentration of labile carbon. These changes could have ecosystem and landscape-wide impacts
Goose persistence in fall strongly influences Arctic fox diet, but not reproductive success, in the southern Arctic
No full textFood availability is the primary limitation for terrestrial Arctic predators, many of which rely on rodents that fluctuate in abundance over a 3–5-year period. During rodent scarcity, predators such as Arctic foxes (Vulpes lagopus) consume alternative prey, such as migratory birds, which are plentiful during summer. In most of the Arctic these birds return south by August, but in northern Manitoba, near the southern edge of the Arctic fox distribution, large numbers of lesser snow geese (Chen caerulescens caerulescens) and Canada geese (Branta canadensis interior) persist into October. This extended availability of geese late into fall may reduce the dependence of Arctic foxes on rodents.We used stable isotope and faecal analyses to reconstruct the Arctic fox fall and winter diet and related the most probable contributions of lemmings, goose eggs and juvenile geese with changes in prey availability and fox reproduction. Geese were a potentially important component of the fall diet for Arctic foxes, especially in years with high goose productivity, but rodents were the main component of the diet in late winter, even though rodents were scarce each summer (2010–2013). Furthermore, rodent density had a greater influence on Arctic fox reproduction, which was correlated with the subsequent winter harvest, than any other variable examined. Although geese were important fall prey for Arctic foxes at the southern edge of their distribution, they did not buffer declines in availability of rodents, which were the primary prey in April when food availability is critical for Arctic fox reproduction
Abnormal gonads in the Antarctic toothfish (Dissostichus mawsoni Norman, 1937 [Perciformes: Nototheniidae]): the first record and histological description
No full textThis paper describes the morphology and histology of abnormal gonads in Antarctic toothfish (Dissostichus mawsoni) and the possibility of intersexuality and senescence of some individuals. Two old (approximately 25 years) and large (184–185 cm) specimenswith abnormal gonadswere caught in the Antarctic during commercial fishing for toothfish and studied using histological methods. Although D. mawsoni is well-known and extensively studied, this is the first study dealing with abnormal gonads in the species. The histological analysis revealed that the gonads of the first specimen contained both male and female germ cells (ovotestis), the testicular and ovarian tissues being separated by a thick layer of connective tissue. The female portion was composed of secondary vitellogenic oocytes, primary vitellogenic, cortical alveolar and primary growth oocytes, while the testes contained cysts of spermatogonia and primary spermatocyte. The gonads of the second specimen were small, filiform and showed massive growth of the connective tissue, which occupied almost the entire gonad; a few spermatogonia without visible cystswere found. This study extends our understanding of sexual development in Antarctic toothfish, documenting the possibility of long-term interruptions in the reproductive cycle of this species
A histological study of the skin, hair follicles and moult of the hooded seal (Cystophora cristata [Erxleben, 1777])
No full textThe aims of this study were to (1) provide a general description of the hooded seal’s integument; (2) diagnose hair follicle activity stages and develop a chronology for the annual moult within the different sex and age classes; (3) examine the population characteristics of the moult haul-out; and (4) seek possible correlations between these events and the hooded seal’s annual cycle. Skin samples were collected from 68 moulting hooded seals out of 868 taken in the Denmark Strait for population studies during June and July 1972. The microstructure of the integument of this species is described. It varies little from what is known from other northern phocids. However, they appear to be one to two “intermediate” guard hair follicles within up to seven underfur follicles; these are smaller than the main guard hair follicle in each hair follicle complex. The hair follicles in the skin of most hooded seals of both sexes and all ages sampled between 21 June and 11 July 1972 were at early to middle stages of activity, suggesting that hair growth starts somewhat earlier than mid-June and ends later than mid-July. It appears that female moult haul-out numbers started to decline about four to five days earlier than the males, but when the haul-out began or ended could not be determined. The brevity, synchronicity and precision of the moult (and breeding season) suggest that its timing is controlled by an environmental factor such as day length at the high northern latitudes inhabited by hooded seals
Revisiting perceptions and evolving culture: a community dialogue on women in polar research
No full textWomen have made outstanding contributions to polar research in recent decades, though full engagement may be hindered by persistent inequities, including notably the prevalence of workplace harassment. Remote field settings, such as those pervasive in polar research, have been identified as particularly susceptible to cultures of harassment. It was therefore timely at the Polar 2018 Open Science Conference in Davos, Switzerland, to convene a discussion focused on women’s perspectives and experiences. A panel discussion—“From Entering the Field to Taking the Helm: Perspectives of Women in Polar Research”—took place on 20 June 2018 and featured five women undertaking work from marine biotechnology to organizational leadership, across career levels. Over 300 conference attendees joined the lunchtime panel. The panellists’ perspectives on historical barriers, current challenges and future prospects revealed that while challenges persist, experiences vary greatly. Audience engagement underscored the need to sustain dialogue at polar meetings, to bring visibility to the statistics related to workplace harassment and to encourage polar science organizations to assume leadership on promoting equitable workplace culture
A screening for canine distemper virus, canine adenovirus and carnivore protoparvoviruses in Arctic foxes (Vulpes lagopus) and red foxes (Vulpes vulpes) from Arctic and sub-Arctic regions of Norway
No full textCanine distemper virus (CDV), canine adenovirus (CAdV) and canine parvovirus type 2 (CPV-2) cause disease in dogs ( Canis familiaris ). These, or closely related viruses, may also infect wild carnivores. The aim of this study was to investigate exposure to CDV, CAdV and CPV-2 among fox populations in Norway. Arctic foxes ( n = 178) from High-Arctic Svalbard were investigated for antibodies against CDV. Arctic foxes (n = 301) from Svalbard and red foxes from Low-Arctic ( n = 326) and sub-Arctic ( n = 74) regions in Finnmark County, Norway, were investigated for antibodies against CAdV and for the presence of carnivore protoparvovirus DNA in spleen and mesenteric lymph nodes using polymerase chain reaction. Seroprevalence against CDV in Arctic foxes decreased from 25% (1995/96) to 6% (2001/02), whereas the seroprevalence against CAdV increased from 25–40% during the seasons 1995/96 to 2001/02 to 68% for the last study year (2002/03). In red foxes, the seroprevalence against CAdV varied between 31% and 67% for the seasons 2004/05 to 2007/08, increasing to 80% for the last study year. Carnivore protoparvovirus DNA was not detected in any of the 301 Arctic foxes and the 265 red foxes investigated. These results show that CDV and CAdV are enzootic in the Arctic fox population (Svalbard), and that CAdV is enzootic in both the Low-Arctic and sub-Arctic red fox populations (Finnmark). Further studies are needed to better understand the infection biology and the impact of CDV and CAdV in these fox populations, and if viruses may be shared between foxes and other carnivores, including dogs
Circulation and exchange in a broad Arctic fjord using glider-based observations
No full textIn recent years, Svalbard fjords have experienced a substantial reduction in winter sea-ice extent. This has been linked to changes in wind stress patterns over Fram Strait and an increased transport of warm Atlantic Water into the fjords. In November 2014, we deployed two Slocum gliders to Isfjorden and measured the hydrographical properties and depth-averaged currents in the region. The campaign marked the first time gliders have been used inside an Arctic fjord. We observed geostrophically balanced flow patterns both in the mouth, where the heat flux into the fjord was calculated to be 0.13 TW, and in the interior of Isfjorden, where geostrophic flows were up to 20 cm s −1 . After a change in the prevailing wind direction on the West Spitsbergen Shelf, we found evidence for a wind-driven geostrophic control mechanism at the fjord mouth, impeding fjord–shelf exchange, and found that the geostrophic circulation inside the fjord had broken down. We conclude that the circulation patterns in Isfjorden are heavily influenced by rotational effects and by wind activity both locally and on the West Spitsbergen Shelf, and that geostrophically balanced exchange flows may deliver Atlantic Water to the fjord interior given the correct conditions at the fjord mouth. The combination of hydrography and high-resolution velocity data from throughout the Isfjorden region provided new insights into the circulation here, suggesting that this approach will be useful for studying high-latitude fjords in the future