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Interval timing measures time estimation in the seconds-to-minutes range. Antarctica provides a real-world context to study the effect of extreme photoperiods and isolation on time perception. The aim of this study was to explore interval timing as a cognitive measure in the crew of Belgrano II Argentine Antarctic Station. A total of 13 subjects were assessed for interval timing in short (3 s), intermediate (6 s) and long (12 s) duration stimuli. Measures were taken during the morning and evening, five times along the year. Significant variations were found for 3 s and 6 s during the morning and 6 s during the evening. Results suggest an impact of isolation on morning performances and an effect of the polar night on evening measures. These findings shed some light on the use of interval timing as a cognitive test to assess performance in extreme environments.

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Macvicaria magellanica n. sp. (Digenea: Opecoelidae) is the third representative of this genus occurring in fish in the Magellanic sub-region of sub-Antarctica and the first one found in sub-coastal waters in this area (the Beagle Channel). Its main taxonomic features include an elongate body, oral:ventral sucker ratio based on widths of 1.0:1.52-1.98, cirrus sac reaching to level of posterior half of the ventral sucker, testes arranged in tandem, numerous vitelline follicles divided into 2 groups separated by a gap parallel to the ventral sucker, vitelline follicles dorsally not confluent at the uterus and gonads, and egg dimensions of 40-51 × 25-32 µm. The most similar species is Macvicaria antarctica, but it differs from the newly described species in having vitelline follicles dorsally confluent at the level of the uterus and by occurring in fish associated with the Falkland-Patagonian shelf at greater depths (at the North Scotia Ridge, 300-500 m). A key to 9 Antarctic and sub-Antarctic species of Macvicaria is included.

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Here we report the isolation of Newcastle disease virus (NDV) from cloacal swabs obtained from penguins in the South Atlantic Antarctic region (62°08S, 58°25W). Samples of 100 penguins from King George Island were tested by real-time PCR, of which 2 (2%) were positive for NDV. The positive samples were isolated in embryonated chicken eggs and their matrix and fusion proteins genes were partially sequenced. This was complemented by the serological study performed on the blood of the same specimens, which resulted in a 33.3% rate of positivity.

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During austral summers 1999-2000 and 2000-01, two outbreaks of avian cholera occurred in the Hope Bay area (63 degrees 24'S, 56 degrees 59'W), located on the tip of the Antarctic Peninsula. Eighty-six dead birds were found: five kelp gulls (Larus dominicanus), 36 skuas (Stercorarius sp.), and 45 Adelie penguins (Pygoscelis adeliae). The carcasses were studied using clinical, pathological, and microbiological criteria. Water samples from ponds where birds were settled and samples from 90 healthy birds also were analyzed during the second outbreak. Pasteurella multocida isolates were identified by biochemical tests, capsular type, somatic serotype, and susceptibility to nine antibiotics. Molecular subtyping was performed by ApaI and SmaI pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC-PCR). In February 2000, mortality in skuas was 16% and 2% in kelp gulls. In the 2000-01 breeding season, mortality in south polar skuas was 47%, 24% in brown skuas, 1.4% in kelp gulls, and 0.01% in Adelie penguins. All birds had lesions of avian cholera. In kelp gulls the presentation was chronic, whereas skuas and penguins suffered subacute and acute disease, respectively. Fifty-five isolates recovered from dead birds and one from water were identified as P. multocida gallicida, type A:1. The strains presented a unique molecular pattern by PFGE and ERIC-PCR. A possible hypothesis to explain the origin of the outbreaks was that nonbreeder kelp gulls carried P. multocida gallicida to Hope Bay, and avian cholera was transmitted through water to skuas and penguins. This study reports avian cholera in new bird species, their potential role in the transmission of the disease, and the different responses of these species to the disease.

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Observations of UV-B radiation in the area of the Antarctic Peninsula are described, with the objective to obtain an evaluation of the UV-B enhancements observed during ozone hole episodes, and compare these with equatorial values. The enhancements observed during Southern Hemisphere spring are described in terms of a specific case of enhancement, at the Antarctic peninsula, which has shown a maximum UV-B index of 8.7, in October 1998. The average enhancement between the autumn-unperturbed and spring-perturbed periods results in an UV-B index of 5.4, but with large fluctuations in which much larger indices are produced. These values are compared to indices normally observed in the equatorial region. For measurements obtained with the same kind of instrument at Natal (5.8 degrees S, 35.2 degrees W), the UV-B index varies between 7 and 14, which means that enhanced UV-B indices in the Antarctic Peninsula may become of the same order of magnitude of the lower limit equatorial values.

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