The effects of thermal stress on antioxidant defences in tissues of the Antarctic clam Laternula elliptica were evaluated and the activities of some antioxidant enzymes, and levels of total glutathione (GSH) and protein carbonyl (PC) in digestive gland and gill over 0–4 days under extreme thermal stress (10°C) were measured. Superoxide dismutase activity was slightly higher after one day of thermal stress, although catalase activity was not altered significantly in either digestive gland or gill tissues. Thermal stress was associated with a significant increase in the activity of GSH-related antioxidant enzymes. Glutathione peroxidase and glutathione reductase activities increased up to 1.8- and 2.0-fold, respectively, after two days of thermal stress. Glutathione S-transferase activity drastically increased, to over 3.4- and 4.2-fold in digestive gland and gill, respectively, and remained high on day four. GSH levels also increased in both tissues and remained high on day four. PC content, a marker of protein oxidation, increased after two days of thermal stress. There is evidence that GSH-related antioxidant defence plays a significant role in relation to potential toxicity from reactive oxygen species during thermal stress.

The initial stages of Umbilicaria aprina Nyl. hydration (starting from the hydration level Δm/m0 = 0.048 ± 0.004) were observed using hydration kinetics, sorption isotherm and proton NMR. The thalli were hydrated from gaseous phase. The total saturation hydration level obtained at the relative humidity p/p0 = 100% was Δm/m0 = 0.848 ± 0.009. The hydration courses revealed i) a fraction of very tightly bound water (Δm/m0 = 0.054 ± 0.011, short hydration time constant, thyd), ii) a fraction of tightly bound water [Δm/m0 = 0.051 ± 0.038, thyd = (4.7 ± 2.6) h], and iii) a loosely bound water pool [thyd = (31.0 ± 1.9) h] for higher values of target humidity. The sorption isotherm of U. aprina was fitted well using Dent model. The relative mass of water saturating primary binding sites was ΔM/m0 = 0.054, which is close to the water fractions. Proton FIDs detected (i + ii) the immobilized tightly bound water fraction, L1, and iii) the mobile, loosely bound water pool L2. The hydration dependence of the proton liquid signal suggests the presence of a significant contribution from a water soluble solid fraction in the thallus. Sorption isotherm fitted to NMR data showed the absence of ‘sealed’ water fraction trapped in pores of the thallus.

We evaluated the condition factor (K), an index of weight per unit length, in a sample of 49 761 longline-caught specimens of Antarctic toothfish, Dissostichus mawsoni, from the Ross Sea. Our sample consisted of specimens from northern (60–70°S) and southern (70–78°S) regions. Fifty percent of the northern sample and 4.9% of the southern sample were large individuals with a low condition factor (Kah ≤ 1.0182) and displaying an “axe handle (ah)” morphology with a notably thinner trunk. In the northern sample 55.4% of the males and 43.2% of the females were less than Kah. In the southern region 5.3% of the males and 4.5% of the females were less than Kah. The axe handle morphology is attributable to the metabolic loss of muscular and subcutaneous lipid stores, and probably proteins, from white muscle. Our discussion considers energy metabolism as related to migration, feeding and reproduction. We suggest that migration, a life history trait of the phyletically basal notothenioid clades Pseudaphritis and Eleginops, persists in D. mawsoni. The spawning migration from the southern shelf to ridges and seamounts in the north may reflect fidelity to historic spawning grounds. As evidenced by the axe handle specimens neutral buoyancy of large D. mawsoni may be ephemeral, fluctuating over the course of adult life.

This paper proposes a new objectively-generated vegetation classification for southern and northern Victoria Land (continental Antarctica) based on the floristic composition of the plant communities. The new classification aims to integrate the existing physiognomic classification of the cryptogamic Antarctic tundra, provide useful data on floristic composition and distribution of the vegetation occurring in southern and northern Victoria Land, and develop a suitable tool allowing easy comparison of syntaxa from different locations. Field data from 26 sites along a latitudinal gradient (72°–77°S) were analysed by a hierarchical classification integrated with multivariate statistics, including indirect ecological information (Principal Component Analysis). Similarity of the identified groups was assessed through the Jaccard similarity index. The new classification is compatible with previous ones and is widely applicable to Victoria Land and includes previous classification. This standardized approach relates plant communities to their floristic composition and provides a basis for relating vegetation composition to environmental gradients and to patterns of vegetation dynamics and succession which are still poorly understood in Antarctica.

Labidiaster annulatus, Sladen (1889) is a multi-rayed (9–50) voracious Antarctic sea star with numerous large, conspicuous crossed pedicellariae. An active and opportunistic predator, it commonly preys upon euphausiids, amphipods, and small fish in the water column (Dearborn et al. 1991). Labidiaster annulatus is distributed around the Antarctic, Kerguelen, South Orkney, South Sandwich Islands, South Georgia, and Shag Rocks, at recorded depths of 30–440 m (Fisher 1940, unpublished data).

Thermal contraction crack polygons modify the generation, transport, and storage of water in Wright Valley gullies. Water generation is contributed to by trapping of windblown snow in polygon troughs. Water transport is modified by changes to the ice-cement table and active layer topography caused by polygon trough formation. Water storage is modified by sediment grain-size distribution within polygons in gully distal hyporheic zones. Patterned ground morphological variation can serve as an indicator of fluvial modification, ranging from nearly unmodified composite-wedge polygons to polygons forming in association with gully channels. Thermal contraction crack polygons may also constrain the gully formation sequence, suggesting the continuous presence of permafrost beneath the Wright Valley gullies during the entire period of gully emplacement. This analysis provides a framework for understanding the relationships between polygons and gullies observed on Mars. If comparable stratigraphic relationships can be documented, the presence of an analogous impermeable ice-cemented layer beneath the gullies can be inferred, suggesting an atmospheric source for Martian gully-carving fluids.

We present two 10Be exposure ages from erratic boulders at Cape Adare, northern Victoria Land. The exposure ages obtained suggest that Cape Adare was covered by ice during the last glacial period, and the younger age points to deglaciation around 16.2 ka. Comparison of our younger 10Be exposure age with published radiocarbon dates for Adélie penguin occupation at Cape Adare suggests that the onset of penguin colonization (at 2–3 kyr before present) lagged behind the deglaciation by at least 11.5 kyr. These observations indicate that penguin colonization did not occur until several thousand years after ice free ground became available.

Penguins (Aves: Sphenisciformes) are interesting to both neontologists and palaeontologists (e.g. Davis & Renner 2003). The fossil record of these extremely specialized inhabitants of the Southern Hemisphere extends back to the Palaeocene epoch (Slack et al. 2006). Extinct penguins are known from localities within the range of their modern-day relatives (Fordyce & Jones 1990), and the oldest diverse assemblage comes from the Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula, the only such locality south of the Antarctic Convergence (Myrcha et al. 2002, Jadwiszczak 2006a). Several collections amounting to over three thousand bones (mainly isolated skeletal elements) have been acquired since 1901 from that formation, and 15 penguin species have been erected so far (Jadwiszczak 2006a, table 1, Tambussi et al. 2006). Only ten of them (grouped into six genera) appear to be taxonomically distinct, and their type specimens are tarsometatarsi (Simpson 1971, Myrcha et al. 2002, Jadwiszczak 2006a, 2006b, p. 296). Individuals from six species belonging to four genera most probably were not larger than those of Aptenodytes forsteri G.R. Gray, 1844, the heaviest and tallest extant penguin (Jadwiszczak 2001, table 3). Interestingly, representatives of all ten species may have co-existed in the West Antarctic during the Late Eocene epoch, just prior to the final break-up of Gondwana (Jadwiszczak 2006a). Presented here is an intriguing partial tarsometatarsus of a small-sized penguin from the Late Eocene of Antarctic Peninsula, probably representing a new genus and species.

Williams et al. (2006) reported asterozoans preserved in Late Miocene volcanic tuffs of the James Ross Island Volcanic Group. The material, from the north-west of James Ross Island at 64°01.9′S 58°20.07′W, was sourced from the newly named Asterozoan Buttress locality, and represented reconnaissance collecting. The volcaniclastic sediments in which the fossils are found are fine- to medium-grained volcanic sandstones with planar, laterally continuous beds 0.5–8 cm thick containing decimetre-scale ripple cross-lamination. In the absence of part and counterpart rock slabs, Williams et al. (2006) hypothesised that the fossils represented the external moulds of starfish or brittlestars pinioned by rapid sedimentation of volcanic tuffs. They noted that these tuffs represented a potential untapped source of fossil material for interpreting Neogene marine shelf environments on the northern Antarctic Peninsula. New fossil material collected at Asterozoan Buttress in February 2007 (by Anna Nelson) includes part and counterpart rock slabs, and demonstrates that the asterozoans are resting traces of animals, referable to the ichnogenus Asteriacites, and not external moulds of entombed animals (Fig. 1a & d). We reinterpret the ‘detached’ arm and ‘current-entrainment’ specimens of Williams et al. (2006, fig. 5c & d) as representing a possible scull mark and movement of the asterozoan across the sediment surface respectively (see Bell 2004, text-fig. 11 for comparison).

Ice cores were sampled at four stations in McMurdo Sound (Ross Sea) between 1999 and 2003. At the beginning of year 2000, a very large iceberg (B-15) detached itself from the Ross Ice Shelf and stranded at the entrance of the Sound, preventing the usual oceanic circulation purging of the annual sea ice cover from this area. Ice textural studies showed that a second year sea ice cover was built-up at three out of the four stations: ice thickness increased to about 3 m. Repeated alternation of columnar and platelet ice appeared, and bulk salinity showed a strong decrease, principally in the upper part of the ice sheet, with associated brine volume decrease. Physical modification influenced the biology as well. By decreasing the light and space available for organisms in the sea ice cover, the stranding of B-15 has i) hampered autotrophic productivity, with chlorophyll a concentration and algae biomass significantly lower for second year ice stations, and ii) affected trophic relationships such as the bacterial biomass/chl a concentration correlation, or the autotrophic to heterotrophic ratio.

Coordinating and collecting satellite data of changing polar environments is one of the prime activities of International Polar Year (IPY) 2007–08 (Rapley et al. 2004). Within this framework, the requirements to obtain spaceborne snapshots of the Polar Regions and key high latitude processes have been prepared by the international cryospheric community under the auspices of the approved IPY project titled the Global Inter-agency IPY Polar Snapshot Year (GIIPSY). Earlier efforts in manoeuvring Radarsat-1 in a special mode provided radar images with a spatial resolution of 30 m over the entirety of Antarctica during September–October 1997 (Jezek et al. 1998). Limited to their altitude (AL), swath (SW) and pointing capability (PC), however, the operation of optical satellites with high-spatial-resolution sensors is generally restricted to certain latitudes. For example, Landsat (AL:705 km/SW:185 km/PC:0°) mission has been able to provide high-spatial-resolution optical imagery only to ~81°N to ~81°S since the 1980s. The coverage is now extended to ~86° by ASTER (AL:705 km/SW:60 km/PC:24°) (Kargel et al. 2005), but there has been no availability of space-borne optical image of the polar regions with a resolution equivalent or higher than Landsat type sensors with latitudes higher than 86°, until the successful operation of Formosat-2 (AL:891 km/SW:24 km/PC: ± 45° across and along track). Equipped with two-axes high torque reaction wheels, Formosat-2 is able to point not only to ± 45° across track, but also to ± 45° along track (Liu et al. 2007). Figure 1 shows the accessible areas (longer lines: along track ± 0°, across track ± 45°; shorter lines: along track ± 0°, across track ± 30°) and the corresponding ground tracks (solid curves) of Formosat-2 in the Polar Regions. Note that the accessible areas would be even greater if the pointing direction is also set to ± 45° along track. The detailed comparison of Formosat-2 with other similar sensors, including the multi-spectral bands and imaging repeat period, can be found in table I in Liu et al. (2007). To support IPY 2007–08, the National Space Organization (NSPO) of Taiwan launched a Polar Imaging Campaign (PIC) in March 2006. Up to September 2007, a total of 1 131 624 km2 in the North Polar Region and a total of 57 408 km2 in the South Polar Region had been imaged by Formosat-2. All Formosat-2 images taken during the NSPO PIC are available from the authors.