Authors:Peter G. Ryan; Jasmine R. Lee, Fabrice Le Bouard Pages: 1 - 9 Abstract: Blue petrels (Halobaena caerulea Gmelin) rapidly moult their flight feathers in Antarctic waters in February–April, immediately following the breeding season, yet the behaviour of moulting birds at sea has not been described. We observed large numbers of moulting blue petrels off West Antarctica from 67–71°S and 78–119°W in mid-February 2017. Most of these birds probably breed at the Diego Ramirez archipelago, southwest of Cape Horn, which is the closest colony to this area. Moulting petrels often sit on the water in dense flocks, just outside the marginal ice zone, at sea temperatures of -0.7 to 0.9°C. Wing moult is intense, with 7–8 inner primaries (62–75% of primary length and 55–69% of primary mass), their corresponding primary coverts and all greater secondary coverts being grown at the same time. Moulting petrels need a reliable food source during this energetically demanding period, so the waters off West Antarctica are probably crucial for the Diego Ramirez population, which makes up more than half of the world's blue petrels. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000427 Issue No:Vol. 32, No. 1 (2020)
Authors:M.G.W. Jones; N.M.S. Techow, M.M. Risi, C.W. Jones, Q.A. Hagens, F. Taylor, P.G. Ryan Pages: 10 - 14 Abstract: A vagrant black-browed albatross Thalassarche melanophris bred with a grey-headed albatross T. chrysostoma on Marion Island at least four times between 2000 and 2009 (and continued to return to the colony until at least 2019). The eggs failed to hatch in three breeding attempts, but the pair fledged a chick in the 2006/07 breeding season. Genetic sexing identified the black-browed albatross as female and she shared all eight sampled microsatellite alleles with the chick, whereas the grey-headed albatross social parent did not match the chick. The fledgling was banded and re-sighted in its natal breeding colony in 2016 and 2018, when it displayed an intermediate black-browed x grey-headed albatross phenotype, similar to a putative hybrid photographed at sea off Australia. These results suggest that the black-browed albatross cuckolded its social mate with another grey-headed albatross in 2006/07. The failures of the other three breeding attempts at the egg stage possibly indicate genetic incompatibility with the social partner. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000506 Issue No:Vol. 32, No. 1 (2020)
Authors:Oliver Gittins; Llorenç Grau-Roma, Rosa Valle, Francesc Xavier Abad, Miquel Nofrarías, Peter G. Ryan, Jacob González-Solís, Natàlia Majó Pages: 15 - 20 Abstract: To evaluate how avian influenza virus (AIV) circulates among the avifauna of the Antarctic and sub-Antarctic islands, we surveyed 14 species of birds from Marion, Livingston and Gough islands. A competitive enzyme-linked immunosorbent assay was carried out on the sera of 147 birds. Quantitative reverse transcription polymerase chain reaction was used to detect the AIV genome from 113 oropharyngeal and 122 cloacal swabs from these birds. The overall seroprevalence to AIV infection was 4.8%, with the only positive results coming from brown skuas (Catharacta antarctica) (4 out of 18, 22%) and southern giant petrels (Macronectes giganteus) (3 out of 24, 13%). Avian influenza virus antibodies were detected in birds sampled from Marion and Gough islands, with a higher seroprevalence on Marion Island (P = 0.014) and a risk ratio of 11.29 (95% confidence interval: 1.40–91.28) compared to Gough Island. The AIV genome was not detected in any of the birds sampled. These results confirm that AIV strains are uncommon among Antarctic and sub-Antarctic predatory seabirds, but they may suggest that scavenging seabirds are the main avian reservoirs and spreaders of this virus in the Southern Ocean. Further studies are necessary to determine the precise role of these species in the epidemiology of AIV. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000464 Issue No:Vol. 32, No. 1 (2020)
Pygoscelis+penguin+diets+on+King+George+Island,+South+Shetland+Islands,+with+a+special+focus+on+the+krill+Euphausia+superba&rft.title=Antarctic+Science&rft.issn=0954-1020&rft.date=2020&rft.volume=32&rft.spage=21&rft.epage=28&rft.aulast=Panasiuk&rft.aufirst=Anna&rft.au=Anna+Panasiuk&rft.au=Justyna+Wawrzynek-Borejko,+Aleksandra+Musiał,+Małgorzata+Korczak-Abshire&rft_id=info:doi/10.1017/S0954102019000543">Pygoscelis penguin diets on King George Island, South Shetland Islands, with a special focus on the krill Euphausia superba
Authors:Anna Panasiuk; Justyna Wawrzynek-Borejko, Aleksandra Musiał, Małgorzata Korczak-Abshire Pages: 21 - 28 Abstract: In the krill-based ecosystem of the Antarctic, fluctuations in the distribution and abundance of Euphausia superba may have strong impacts on predator populations; thus, it is crucial to observe the feeding ecology of Antarctic predators, especially in the light of climate change and increasing human pressure. We determined the composition of euphausiid species in diet samples collected from Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarcticus) and gentoo (Pygoscelis papua) penguins on King George Island (South Shetlands Islands) during a breeding season. For all three penguin species, euphausiids (mainly E. superba) represented almost the entirety of researched stomach samples (i.e. 99.9% in the case of Adélie and chinstrap penguins), while gentoo penguins also proved to feed on fish (99.4% krill; 0.5% fish). Analysed material differed in the size of eaten E. superba specimens, with the smallest crustaceans consumed by Adélie penguins. Furthermore, we found differences in the ratio of consumed krill and krill size. Such disparities may be a result of sex-based differences and slight differences in feeding areas between the birds. Additionally, we noted some fragments of plastic debris in the investigated penguin diet samples. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000543 Issue No:Vol. 32, No. 1 (2020)
Authors:Matti Leppäranta; Arto Luttinen, Lauri Arvola Pages: 29 - 42 Abstract: Shallow Antarctic surface lakes belong to the most extreme aquatic environments on the Earth. In Vestfjella, proglacial surface lakes and ponds are characterized by a 2–5 month long period with liquid water and depths < 2 m. We give a detailed description of nine seasonal lakes and ponds situating at three nunataqs (Basen, Plogen and Fossilryggen) in western Dronning Maud Land. Their physical and geochemical properties are provided based on observations in four summers. Three main ‘lake categories‘ were found: 1) supraglacial lakes, 2) epiglacial ponds and 3) nunataq ponds. Category 3 lakes can be divided into two subgroups with regards to whether the meltwater source is glacial or just seasonal snow patches. Supraglacial lakes are ultra-oligotrophic (electrical conductivity < 10 μS cm−1, pH < 7), while in epiglacial ponds the concentrations of dissolved and suspended matter and trophic status vary over a wide range (electrical conductivity 20–110 μS cm−1, pH 6–9). In nunataq ponds, the maxima were an electrical conductivity of 1042 μS cm−1 and a pH of 10.1, and water temperature may have wide diurnal and day-to-day fluctuations (maximum 9.3°C) because snowfall, snow drift and sublimation influence the net solar irradiance. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000555 Issue No:Vol. 32, No. 1 (2020)
Authors:James B. McClintock; Charles D. Amsler, Margaret O. Amsler, William R. Fraser Pages: 43 - 44 PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S095410201900052X Issue No:Vol. 32, No. 1 (2020)
Authors:Xiaochun Liu; Bin Fu, Qiuli Li, Yue Zhao, Jian Liu, Hong Chen Pages: 45 - 57 Abstract: This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages of 910 Ma for larger granular grains and 670–630 Ma for smaller globular beads around garnet porphyroblasts or hosted by symplectites. Rutile from leucogneiss yields U–Pb ages of 520–515 Ma. Hornblende and biotite from different rock types yield 40Ar/39Ar plateau ages of 744 and 520–505 Ma, respectively. Combining these results with published zircon U–Pb age data suggests that granulite facies metamorphism occurred at 910 Ma, with a local low-temperature fluid flow event at 670–630 Ma and thermal reworking at 520–505 Ma. The older age of 744 Ma may reflect cooling or partial resetting of the hornblende 40Ar/39Ar system, indicating that Pan-African-aged reworking did not exceed temperatures much higher than the hornblende Ar closure temperature. These data also suggest that the complete isotopic resetting of some minerals may occur without the growth of new mineral phases, providing an example of the style of reworking that is likely to occur in polymetamorphic terranes. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000518 Issue No:Vol. 32, No. 1 (2020)
Authors:John W. Wilson; Liam A. Marsh, Wouter Van Verre, Michael C. Rose, Geoffrey Evatt, Andrew R.D. Smedley, Anthony J. Peyton Pages: 58 - 69 Abstract: Iron-rich meteorites are significantly underrepresented in collection statistics from Antarctica. This has led to a hypothesis that there is a sparse layer of iron-rich meteorites hidden below the surface of the ice, thereby explaining the apparent shortfall. As standard Antarctic meteorite collecting techniques rely upon a visual surface search approach, the need has thus arisen to develop a system that can detect iron objects under a few tens of centimetres of ice, where the expected number density is of the order one per square kilometre. To help answer this hypothesis, a large-scale pulse induction metal detector array has been constructed for deployment in Antarctica. The metal detector array is 6 m wide, able to travel at 15 km h-1 and can scan 1 km2 in ~11 hours. This paper details the construction of the metal detector system with respect to design criteria, notably the ruggedization of the system for Antarctic deployment. Some preliminary results from UK and Antarctic testing are presented. We show that the system performs as specified and should reach the pre-agreed target of the detection of a 100 g iron meteorite at 300 mm when deployed in Antarctica. PubDate: 2020-02-01T00:00:00.000Z DOI: 10.1017/S0954102019000531 Issue No:Vol. 32, No. 1 (2020)
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