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  • 1. Gudmundsson, GA
    et al.
    Alerstam, T
    Larsson, B
    Radar observations of northbound migration of the Arctic Tern Sterna paradisaea at the Antarctic Peninsula1992In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 4, no 2, p. 163-170Article in journal (Refereed)
    Abstract [en]

    An intensive migration of Arctic terns was observed from 7-9 March 1989 in Marguerite Bay (67-degrees-50'S 67-degrees-30'W). The movement pattern and speed of tern flocks were analysed from time-lapse films of a marine navigation radar. The terns migrated north at altitudes 30-60 m asl along the inner coast of Marguerite Bay. When approaching Pourquois Pas Island, the majority veered to the NNE flying into Bourgeois Fjord. Mean flock size was 11.6 (s.e. = 1.9). The estimated total during the three observation days was about 7600 migrating terns. Analysing flight speed in relation to wind showed that the terns increased their airspeed when flying into headwinds and decreased it with following winds. The terns' airspeeds, with an estimated mean of 11.3 ms-1 (s.e. = 1.3) with no wind effect, were significantly faster than the predicted maximum range speed. It is suggested that the terns were migrating- on a connecting route between the pack ice of the Bellingshausen and Weddell Seas, involving a flight across the Antarctic Peninsula. Topographical conditions are favourable for such a passage close to the observation site in Marguerite Bay, where the distance across the 1500 m high ice cap of the Antarctic Peninsula is only 37 km. It remains to be clarified if the suggested migration route is of importance for regional tern populations only, or if it is part of a circumpolar Antarctic migration pattern.

  • 2. Hansson, Lars-Anders
    et al.
    Hylander, Samuel
    Dartnall, Herbert J.G.
    Lidström, Sven
    Svensson, Jan-Erik
    High zooplankton diversity in the extreme environments of the McMurdo Dry Valley lakes, Antarctica2012In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 24, no 2, p. 131-138Article in journal (Refereed)
    Abstract [en]

    The McMurdo Dry Valley lakes of Antarctica constitute some of the harshest and most isolated freshwater environments on Earth which might be expected to limit the biogeographical expansion of many organisms. Despite this, we found that the biodiversity of rotifer zooplankton is the highest ever recorded on the Antarctic mainland. We identified in total nine rotifer taxa, of which six are new to the Antarctic continent, in Lake Hoare, and also the first sub-adult crustacean copepod belonging to the genus Boeckella. A possible explanation for the high biodiversity is that many of the recorded species have arrived in the region in relatively recent times and then established invasive populations, suggesting that their distribution pattern was previously limited only by biogeographical borders. Interestingly, we show that the cosmopolitan rotifer taxa identified are relatively abundant, suggesting that they have established viable populations. Hence, our study suggests that the biogeographical maps have to be redrawn for several species.

  • 3. JADWISZCZAK, Piotr
    et al.
    Mörs, Thomas
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    First report on quill pits in early penguins2016In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079Article in journal (Refereed)
  • 4. Pearce, David A.
    et al.
    Cockell, Charles S.
    Lindstrom, Eva S.
    Tranvik, Lars J.
    First evidence for a bipolar distribution of dominant freshwater lake bacterioplankton2007In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 19, no 2, p. 245-252Article in journal (Refereed)
    Abstract [en]

    As a result of the recent application of DNA based technology to the investigation of maritime Antarctic freshwater lakes, patterns have begun to emerge in the bacterioplankton communities that dominate these systems. In this study, the bacterioplankton communities of five Antarctic and five Arctic freshwater lakes were assessed and compared with existing data in the literature, to determine whether emerging patterns in Antarctic lakes also applied to Arctic systems. Such a bipolar comparison is particularly timely., given the current interest in biogeography, the global distribution of microorganisms and the controversy over the global ubiquity hypothesis. In addition, it has recently been discovered that commonly encountered bacterial sequences, often originating from uncultivated bacteria obtained on different continents, form coherent phylogenetic freshwater clusters. In this study we encountered both identical sequences and sequences with a high degree of similarity among the bacterioplankton in lake water from both poles. In addition, Arctic freshwater lakes appeared to be dominated by some of the same groups of bacterioplankton thought to be dominant in Antarctic lakes, the vast majority of which represented uncultivated groups.

  • 5.
    Wulff, Angela
    et al.
    Univ Gothenburg, Dept Marine Ecol, SE-40530 Gothenburg, Sweden..
    Zacher, Katharina
    Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany..
    Hanelt, Dieter
    Univ Hamburg, Biozentrum Klein Flottbek, D-22609 Hamburg, Germany..
    Al-Handal, Adil
    Univ Gothenburg, Dept Marine Ecol, SE-40530 Gothenburg, Sweden..
    Wiencke, Christian
    Alfred Wegener Inst Polar & Marine Res, D-27570 Bremerhaven, Germany..
    UV radiation - a threat to Antarctic benthic marine diatoms?2008In: Antarctic Science, ISSN 0954-1020, E-ISSN 1365-2079, Vol. 20, no 1, p. 13-20Article in journal (Refereed)
    Abstract [en]

    This investigation was motivated by the lack of ultraviolet radiation (UVR, 280-400 nm) studies on Antarctic benthic marine microalgae. The objective was to estimate the impact of UV-B (280-315 nm) and UV-A (315-400 nm), on photosynthetic efficiency, species composition, cell density and specific growth rate in a semi-natural soft-bottom diatom community. In both experiments, cell density increased over time. The most frequently observed species were Navicula cancellata, Cylindrotheca closterium, Nitzschia spp., and Petroneis plagiostoma. For both experiments, a shift in species composition and a decreased photosystem II (PSII) maximum efficiency (F(v)/F(m)) over time was observed, irrespective of treatment. UVR significantly reduced F(v)/F(m) on days 3 and 10 (Expt 1), disappearing on the last sampling date. A similar trend was found in Expt 2. A significant UV effect on cell density was observed in Expt 1 (day 10) but not in Expt 2. No treatment effects on species composition or specific growth rate were found. Thus, the UV effects were transient (photosynthetic efficiency and cell density) and the growth of the benthic diatoms was generally unaffected. Overall, according to our results, UVR does not seem to be a threat to benthic marine Antarctic diatoms.

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