Polar Research (E-Journal)
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Gastrointestinal parasites of two populations of Arctic foxes (Vulpes lagopus) from north-east Greenland
No full textParasitological examination of 275 faecal samples from Arctic foxes (Vulpes lagopus) collected at Zackenberg Valley and Karupelv Valley in north-east Greenland from 2006 to 2008 was conducted using sieving and microscopy. Overall, 125 (45.5%) samples contained parasite eggs of Taenia crassiceps, Taenia serialis, Toxascaris leonina, Eucoleus boehmi, Physalopteridae and Ancylostomatidae, and Strongyloides-like larvae. As long-term ecological studies are conducted at both sampling locations, the present findings constitute a baseline data set for further parasitological monitoring
Potential chemical defenses of Antarctic benthic organisms against marine bacteria
No full textThe continental shelf of Antarctica harbours rich suspension-feeding macroinvertebrate communities that are continuously exposed to large populations of free-living microbes. To avoid settlement or fouling by undesirable microorganisms that could cause infection or collapse filter-feeding systems, these macroinvertebrates might regulate the epibiotic microbial mat through chemical interactions. In Antarctic chemical ecology, the antibacterial roles of natural products remain mostly unknown. A necessary first step is to identify organisms that produce compounds with potential ecological relevance. For that reason, we tested the crude organic extracts of 116 taxa of Antarctic benthic organisms for antibacterial activity against a panel of seven strains of marine bacteria. Nine out of 11 phyla tested had antibacterial properties. However, inhibitory activity was quite selective and species-specific. These patterns suggest that Antarctic benthic organisms may produce diverse bioactive metabolites with different antibacterial activities or, alternatively, those contrasting profiles may be shaped by environmental and biological interactions acting at a small spatial scale. The reasons of such selectivity remain to be further investigated and may contribute to the identification of bioactive compounds with pharmaceutical applications
Morphology of seamounts at the Mendeleev Rise, Arctic Ocean
No full textGeological and geophysical studies undertaken during the Russian Arktika-2012 Expedition of 2012 produced evidence of basement outcrops on the steep slopes of the Mendeleev Rise seamounts. Observations of the outcrops from research submarines showed that part of the steep slopes interpreted as basement outcrops based on seismic data were overlain by a light sediment cover. The actual areas of the basement outcrops are therefore much less than indicated by the seismic data alone. The outcrops found are of 5–10 to 100–200 m and are often stretched along some hypsometric level or arranged obliquely, crossing a slope at an angle to the horizon. The rocks are massive and layered, often strongly weathered, cavernous, with visible fissures and extended by dislocations
Polaris: the chief scientist’s recollections of the American North Pole Expedition, 1871-73
No full textThis important translation places German scientist Emil Bessels’ own account of the ill-fated American Polaris North Pole expedition in the English language for the first time
Captain Scott: icy deceits and untold realities
No full textCaptain Scott holds a unique position in human exploration in that, despite his failures, he has obtained a status often above and beyond his ultimately more successful adversary Roald Amundsen. In a field which only celebrates the victor how did this come to pass? Perhaps it is because that, although failing to reach the South Pole first, his subsequent demise on the icy continent symbolized the extremes humans undergo in the name of exploration, the very real prospect of failure, and the strength of the human spirit. His untimely death elevated Scott from second place finisher to that of martyr – a man sacrificing himself in the name of discovery. Until now a multitude of books have analysed Scott’s expedition to the Pole in great detail, without ever questioning whether Scott’s legendary status is justified or indeed deserved
Molluscan assemblages associated with Gigartina beds in the Strait of Magellan and the South Shetland Islands (Antarctica): a comparison of composition and abundance
No full textIn this paper we evaluated the composition and abundance of molluscs associated with beds of the red algae Gigartina, located in the South Shetland Islands (Antarctic Peninsula) and the Strait of Magellan (southern Chile). During the summer season of 2013, samples were obtained by scuba diving using a 0.25 m2 quadrat, arranged randomly within the bed. We extracted a total of 15 quadrats per sampling site. For Antarctic Peninsula beds the most abundant species were the bivalve Lissarca miliaris (233 individuals) and the gastropod Laevilacunaria antarctica (94 individuals), while for Strait of Magellan beds the most abundant species was the polyplacophoran Callochiton puniceus (36 individuals). Comparative analysis between the two molluscan assemblages showed significant differences in the faunal composition between the Antarctic Peninsula and Strait of Magellan (f = 64.474; p = 0.0001). Therefore, molluscs reported in both areas are characteristic of their respective biogeographic area. Finally, Gigartina species play an important role in the formation of patterns of abundance and diversity of the communities associated with them
Meso-scale variations in diet composition of little auk chicks in north-west Spitsbergen
No full textColonial seabirds from neighbouring breeding aggregations may share foraging grounds or utilize different areas in order to decrease the competition over food resources. In our study, we present the meso-scale variations in the diet composition of zooplanktivorous little auk chicks (Alle alle), based on samples collected over two years in two neighbouring colonies (Aasefjellet and Magdalenefjorden) located in north-west Spitsbergen, Svalbard. Although the colonies are situated only 10 km apart, they differ in geographical features (in-fjord vs. coastal). The main findings of our study were significant inter-colony and inter-year differences in the total abundance of diet items and in abundance of particular components. The open-sea species Themisto abyssorum was more abundant in the diet of chicks from Aasefjellet, situated in the outer coast. Another open-sea species, Calanus hyperboreus was also characteristic for this colony but only in the first year of study. On the other hand, the ice-associated amphipod Apherusa glacialis was regularly observed in the diet of little auk chicks from the Magdalenefjorden colony, which is located closer to the marginal ice zone. The differences observed in the diet composition of birds from the two neighbouring sites may indicate that two colonies of birds have at least partly separate foraging areas. Our results could also suggest flexibility in the little auk’s foraging behaviour that enables it to adapt to local feeding conditions. Thus, our study significantly contributes to the deeper understanding of little auks’ feeding strategies in the changing environment of northern Spitsbergen
Tilt signals at Mount Melbourne, Antarctica: evidence of a shallow volcanic source
No full textMount Melbourne (74°21′ S, 164°43′ E) is a quiescent volcano located in northern Victoria Land, Antarctica. Tilt signals have been recorded on Mount Melbourne since early 1989 by a permanent shallow borehole tiltmeter network comprising five stations. An overall picture of tilt, air and permafrost temperatures over 15 years of continuous recording data is reported. We focused our observations on long-term tilt trends that at the end of 1997 showed coherent changes at the three highest altitude stations, suggesting the presence of a ground deformation source whose effects are restricted to the summit area of Mount Melbourne. We inverted these data using a finite spherical body source, thereby obtaining a shallow deflation volume source located under the summit area. The ground deformation observed corroborates the hypothesis that the volcanic edifice of Mount Melbourne is active and should be monitored multidisciplinarily.
Keywords: Tilt monitoring; volcanic dynamics; physics volcanology; ground deformation; Victoria Land
The origins of white-chinned petrels killed by long-line fisheries off South Africa and New Zealand
No full textThe white-chinned petrel (Procellaria aequinoctialis) is the seabird species most frequently killed by fisheries in the Southern Ocean and is listed by the International Union for the Conservation of Nature and Natural Resources as globally vulnerable. It breeds around the sub-Antarctic, but genetic data identified two subspecies: P. a. aequinoctialis from islands in the Atlantic and Indian Oceans and P. a. steadi from the New Zealand sub-Antarctic islands. We identify the region of origin of birds killed by two long-line fisheries based on differences in the mitochondrial gene cytochrome b. All 113 birds killed off South Africa had the haplotype of P. a. aequinoctialis, whereas all the 60 birds from New Zealand had P. a. steadi haplotypes. The two subspecies of white-chinned petrels thus appear to disperse to different regions irrespective of their age, which accords with the tracking data of adult birds. Our finding has significant implications for managing the bycatch of this species by regional fisheries.Keywords: Fishery bycatch; Procellaria aequinoctialis; genetic structure; genetic diversity; demographic impact.(Published: 21 June 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, 21150, http://dx.doi.org/10.3402/polar.v35.2115
Regurgitation of the koilin layer in chinstrap penguins (Pygoscelis antarcticus) and its association with gastric parasites
No full textThe koilin membrane, formed by the secretions of the ventricular and pyloric glands, functions as a protective layer in the gizzards of most bird species. However, the ecological functions of koilin have never been studied in free-ranging penguins. During the two austral summers from 2012 to 2014, we observed the regurgitated koilins of chinstrap penguins (Pygoscelis antarcticus) at Narębski Point on King George Island, South Shetland Islands, and we detected a significant difference in the daily accumulation of regurgitated koilins between the pre-hatching and post-hatching periods in the rookery. We also found 233 gastrointestinal parasites, all Stegophorus macronectes (Nematoda, Acuariidae), from 26 out of 45 koilins freshly regurgitated by chinstrap penguins. We suggest that the regurgitation of koilins may benefit adult chinstrap penguins in the wild by reducing parasitic loads when they fast during incubation; it may also help decrease the risk of parasite transmission to chicks. Our results present the first observations of regurgitated koilins among breeding chinstrap penguins. How koilin regurgitation functions in penguins requires further study. Among the gentoo penguins (P. papua) co-occurring at the study site, we observed no regurgitated koilin layers.Keywords: Cuticula gastris; host-parasite interaction; nematodes; parasitic load; regurgitation; Stegophorus macronectes.(Published: 21 June 2016)Citation: Polar Research 2016, 35, 25966, http://dx.doi.org/10.3402/polar.v35.2596