A compositionally varied swarm of mafic dykes in the Jetty Peninsula area was emplaced about 320 Ma ago (K-Ar age). There are three major groups: Group 1 dykes range from transitional-alkaline dolerites to camptonites, Group 2 are trachydolerites, and Group 3 are diorite to quartz diorite porphyries. Group 1 dykes have very similar ratios of most incompatible elements and were derived from the same (or a very similar) enriched lithospheric mantle source region (∈Nd −0.18 to −3.05) with high Nb and Ta (i.e., OIB, ocean island basalt, characteristics). However, the presence of several distinct subgroups with different incompatible element abundances implies significantly different degrees of melting. Group 2 trachy dolerites are much more fractionated (mg 22–36), but were apparently derived from a similar, although somewhat more enriched (∈Nd −2.26 to −4.63) source. Group 3 diorites are compositionally quite distinct and may have been derived by intracrustal melting. Enrichment of the mantle source(s) of Groups 1 and 2 dykes apparently occurred about the same time as high-grade metamorphism in the area, and may have been coeval with crust formation in nearby parts of Gondwana.

Antarctica is one of the most suitable locations for the bioprospecting of psychrotrophic fungi, which play a key role in the nutrient cycle and organic material mineralization in cold environments. These actions mainly take place via the production of several cold-active extracellular enzymes. The aim of this study was to investigate the diversity of filamentous fungi from King George Island (25 De Mayo Island), Antarctica and their ability to produce extracellular hydrolytic enzymes at low temperatures. A total of 51 fungal isolates were obtained from 31 samples. Twelve genera were identified, with seven among the Ascomycota (Cadophora, Helotiales, Monographella, Oidodendron, Penicillium, Phialocephala, Phialophora, Phoma and Pseudogymnoascus), one Basidiomycota (Irpex) and two Mucoromycota (Mortierella and Mucor). Monographella lycopodina and Mucor zonatus, not previously reported in Antarctica, were identified. Nine isolates could not be identified to genus level and may represent novel species. Most of the studied fungi were psychrotrophic (76.5%). Nevertheless, only five isolates were able to grow at 35°C, 15°C being the optimal growth temperature for 65% of the fungal isolates. Results from enzyme production at low temperature revealed that the Antarctic environment contains metabolically diverse fungi, which represent potential tools for biotechnological applications in cold regions.

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.

Wide-ranging, surface-feeding pelagic seabirds are the most numerous functional group of birds in the Southern Ocean. The mesoscale habitat use of these birds is increasingly being quantified by relating their movements to remotely sensed, near surface properties of the ocean. However, prey availability at the sea surface may also be determined by habitat characteristics not measurable from space. For instance, benthic-pelagic coupling, which occurs when seabed processes affect productivity in the epipelagic zone, can link benthic habitat type to availability of surface prey. We combined acoustically derived maps of the substrate of the South Georgia shelf with GPS tracking to quantify the sub-mesoscale habitat use of breeding black-browed albatrosses. We show that albatrosses preferentially used waters overlaying glacial moraine banks near the shelf edge and that this was unrelated to the presence of trawlers targeting mackerel icefish, which are also associated with these features. Stomach temperature profiles suggest that albatrosses primarily caught krill and fish over the banks. We hypothesize that black-browed albatrosses target waters overlaying moraine banks due to upward benthic-pelagic coupling, mediated by an increase in abundance of zooplankton such as Antarctic krill. Our findings suggest that the potential effects of such processes on pelagic seabird distribution warrant wider investigation.

The effect of low temperature on Umbilicaria aprina collected from Schirmacher Oasis, East Antarctica, was determined over a wide range of hydration using proton free induction decays, proton nuclear magnetic resonance (NMR) spectra and differential scanning calorimetry methods. The proton NMR line is a superposition of the broad component from the solid matrix of the thallus and a narrower component from the averaged bound water pool. Proton free induction decays may be resolved into three components: a solid component well described by the Abragam function and two exponentially decaying components from water loosely bound and water tightly bound in the thallus. With decreased temperature the loosely bound water pool (freezing water) is transferred to the tightly bound water pool (non-freezing water), and vanishes below -40°C. Bound water freezing and melting temperatures decrease with the decrease of hydration level, suggesting that heterogeneous ice nucleation is responsible for water freezing. The onset of bound water freezing temperature is c. 10°C lower than the melting temperature. The U. aprina thalli do not reveal the ability to stimulated ice nucleation at higher temperature. Freeze-thaw cycles showed that for n > 5 cycles no substantial change occurs in the difference between melting and freezing temperatures.

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.

Two short gravity cores were retrieved to obtain palaeoclimatic information from Maxwell and Admiralty bays, King George Island, South Shetland Islands. AMS 14C age dates, sediment properties (grain size, TOC and CaCO3) and stable oxygen and carbon isotope compositions of benthiδ foraminifera (Globocassidulina biora) show downcore variations that characterize depositional conditions during the late Holocene. In particular, δ18O values of benthic foraminifera are lowest at approximately 2500 yr bp in both cores. Allowδ18O time-equivalent excursion in both cores is interpreted to reflect a distinct subglacial meltwater discharge intensified by warm climatic conditions. An increased proportion of fine-grained detritus and higher TOC in the cores at this level suggests that enhanced meltwater supply may have resulted in increased primary productivity. This meltwater discharge event provides evidence of climatic instability during the late Holocene at King George Island.

Eight taxa of marine invertebrates, including two new bivalve species, are described from the Low Head Member of the Polonez Cove Formation (latest early Oligocene) cropping out in the Vauréal Peak area, King George Island, West Antarctica. The fossil assemblage includes representatives of Brachiopoda (genera Neothyris sp. and Liothyrella sp.), Bivalvia (Adamussium auristriatum sp. nov., ?Adamussium cf. A. alanbeui Jonkers, and Limatula (Antarctolima) ferraziana sp. nov.), Bryozoa, Polychaeta (serpulid tubes) and Echinodermata. Specimens occur in debris flows deposits of the Low Head Member, as part of a fan delta setting in a high energy, shallow marine environment. Liothyrella sp., Adamussium auristriatum sp. nov. and Limatula ferraziana sp. nov. are among the oldest records for these genera in King George Island. In spite of their restrict number and diversification, bivalves and brachiopods from this study display an overall dispersal pattern that roughly fits in the clockwise circulation of marine currents around Antarctica accomplished in two steps. The first followed the opening of the Tasmanian Gateway at the Eocene/Oligocene boundary, along the eastern margin of Antarctica, and the second took place in post-Palaeogene time, following the Drake Passage opening between Antarctic Peninsula and South America, along the western margin of Antarctica.

The Selborne Group comprises two metamorphic rock units, the muscovite±dolomite bearing Madison Marble and the biotite-muscovite±quartz-calcite Contortion Schist, which contains thick lenses of variably deformed metabasalts and metaconglomerates. Petrological and structural data indicate a polyphase metamorphic evolution including: i) an early stage of upper greenschist regional metamorphism (P = ~0.15–0.3 GPa; T = ~380–450°C), ii) prograde metamorphism during D1 up to amphibolite facies peak conditions (P = 0.58–0.8 GPa, T = ~560–645°C), iii) syn-D2 unloading-cooling retrograde metamorphism, iv) a post-D2 contact metamorphic overprint at variable T between 450 and 550°C and ~0.2 GPa connected to the emplacement of granitic plutons and felsic dyke swarms. Geochronological data constrain the polyphase syn-D1/D2 evolution between ~ 510 and 492 Ma. A similar metamorphic path, including a medium P stage but at lower T conditions, is documented in greenschist facies metabasalts within the Byrd Group in the Mount Dick area. The metamorphic pattern and close lithostratigraphic matching between Selborne Group and Byrd Group sharply contrast with the high-grade Horney Formation that is exposed north of the Byrd Glacier and corroborate the hypothesis that the Byrd Glacier discontinuity marks a first-order crustal tectonic boundary crossing the Ross orogen.

Two specimens of Kondakovia longimana were recently obtained from the Indian Ocean sector of the Southern Ocean. One specimen, damaged but near the known maximum size, was found floating on the surface, and the other, a male subadult specimen, was captured by a pelagic trawl. Examination of the specimens, histological sections and analyses of tissue samples revealed that the muscular tissues of the tentacular stalks and the mantle contain a large amount of ammonium, more than 328 mM, a quantity that far exceeds that of Moroteuthis ingens (206.9 mM) and Moroteuthis robsoni (199.6 mM) from the South Tasman Rise. Catch data and published records suggest that the juveniles and subadults of K. longimana feed on krill in the epipelagic zone.

Although the beneficial effects of endophytic bacteria on their host are significant, the investigation of the microbial diversity in any Antarctic moss has been neglected. In this study, we investigate the endophytic bacterial diversity of the upper green part and the lower brown part of Sanionia uncinata through 16S rRNA genes using pyrosequencing. Proteobacteria was the most dominant phylum with 65.6%, followed by Bacteroidetes (29.1%) and Actinobacteria (11.7%). The different distribution of Alphaproteobacteria between the upper green (2%) and lower brown (22.2%) parts of the moss was significant. Furthermore, dominant and diverse species were detected and closely related to the environmental sequences. These findings suggest that there are likely to be specific relationships between endophytes and host Antarctic moss species.

We observed ice formation and water column attributes in four shallow Antarctic ponds between January and 7 April 2008. During that time ponds went from ice-free to > 80 cm thick ice, near-freshwater to hypersaline, well-lit to near darkness and temperatures fell to below zero. Here we examine shifts in biological activity that accompanied these changes. During February, freeze-concentration and ongoing photosynthesis increased dissolved oxygen concentration to up to 100 mg l-1, with a near-equivalent decrease in dissolved inorganic carbon and a pH rise. Benthic photosynthesis was responsible for 99% of estimated biological oxygen production. Net oxygen accumulation ceased in late February, pH began to fall and inorganic carbon to increase, but the pool of dissolved oxygen was depleted only slowly. Anoxia had been attained in only one pond by April and there was little accumulation of indicators of anaerobic activity. The nitrogen and phosphorus balances of the ponds were dominated by organic forms, which, like DOC and CDOM, behaved conservatively. Conversely, inorganic nitrogen and phosphorus uptake was evident throughout the study period, at a molar ratio of 16N:1P in two of three ponds, consistent with uptake into biological material. We found no coupling between N and P uptake and photosynthesis.

We report measures of absorption (negative log10 of the transmissivity) of a collimated beam through a 2.27 mm surface layer of Beacon Sandstone that harbours a cryptoendolithic microbial community. Consistent with the findings of previous work in the visible light range with these rocks, and in analogous sediments, blue wavelengths are more strongly attenuated than red. At wavelengths from 2400–1200 nm the absorption of the dry rock layer is roughly constant at 3.1 except in the water bands at 2000 nm and 1600 nm. From 1200–300 nm the absorption increases from 3.1 to 6.4, below 300–190 nm (the lowest wavelength measured) the absorption exceeds 6.4. When the rock is saturated with water the absorption uniformly decreases by about 0.1–0.2 over the 700–400 nm region but decreases sharply for lower wavelengths, with the decrease equal to 0.5 at 300 nm. Thus, the relative protection against UV is attenuated when the rock is wet. Even with this decreased absorption the UV absorption is still greater than that for the visible. The absorption at wavelengths less than 300 nm was too large to measure (> 6.4) for both the wet and dry rocks.

The oxygen and hydrogen isotope composition of waters in a small valley at Signy Island, South Orkney Islands, were monitored over three summers (1999 to 2001). These stable isotopes track water movement through the catchment, especially seasonal precipitation and snow melt. All samples fall close to the regional meteoric water line but factors other than air temperature cause year-to-year variability. Residence times are in the order of days thus the lake water provides an average of precipitation falling only a few days before, except in the winter when the lakes are effectively closed. Freezing of surface waters preserves the isotope signature of the underlying waters from the previous summer. In spring, meltwaters from winter snow are isotopically depleted having δ18O and δD as low as -13‰ and -100‰ (VSMOW). Ice- cover break-up in late December allows complete water column mixing. By February, the lakes are relatively enriched isotopically (δ18O -9‰) by summer precipitation. Precipitation isotopic composition at Halley Station, Brunt Ice Shelf, is similar, illustrating the broad-scale effects of the Weddell Sea cyclonic atmospheric circulation. These data form a useful reference data-set for the ground-based validation of atmospheric models and palaeoclimate reconstructions in this isolated sector of the South Atlantic Ocean.

Cribroelphidium webbi sp. nov. is the only adequately described sub-Recent elphidiid foraminifer from Antarctica. In Admiralty Bay (King George Island, South Shetland Islands), it is found at several locations within inner fiord setting at water depths between 33 and 165 m, but most commonly shallower than 100 m. In outer basins this foraminifer is absent. In the cores analysed, C. webbi sp. nov. is present in well-constrained sub-Recent horizons that are clearly related to climate warming and deglaciation. These horizons represent a diachronous facies marker rather than a single stratigraphic layer. Cribroelphidium webbi sp. nov. shows clear association with retreating tidewater glaciers, therefore it is an important sensitive glacier-proximal indicator. It appears that it shares similar ecologic affinities with Cribroelphidium excavatum clavatum, which is widely distributed throughout the Arctic.

The French-Italian Concordia (CCD) seismological station at Dome C is one of two observatories setup on the ice cap in the interior of the Antarctic continent. We analysed the seismic signal due to ambient noise at this station and at three temporary stations 5 km away from Concordia, in order to specify the ice properties beneath them. A method based on the horizontal to vertical (H/V) spectral ratio, commonly used to analyse soil response in seismic regions, was applied to the Antarctic stations. The main peak in the spectral ratios is observed at frequencies 6.7–8 Hz at the Dome C stations, but it is not observed at another station on the ice cap, QSPA, where the sensor is buried at 275 m depth. This peak can be explained by a 23 m thick unconsolidated snow or firn layer with a low S-wave velocity of 0.7 km s-1, overlying a consolidated layer with S-wave velocity 1.8 km s-1. Despite the non-uniqueness of the solutions obtained by fitting the H/V spectra, this model is preferred because the depth of the velocity contrast coincides with the density at which ice particles arrange themselves in a continuous, dense lattice. A small variability of this structure is observed around Dome C.

Northern (Macronectes halli) and southern (M. giganteus) giant petrels breed at different times at sub-Antarctic Marion Island. Long-term census and breeding success data are used to test for competitive overlap between the two species by correlating population trends with those of land-based prey/carrion species. No parameter was singularly important in population regulation of either giant petrel species and the assumed dependence of breeding northern giant petrels on southern elephant seal Mirounga leonina carrion is not entirely supported.

Antarctica is currently the most productive region of the Earth for the recovery of meteorites and over 9800 specimens have been found there, most of these since 1969. This material consists of meteoritic fragments representing a much smaller, but unknown, number of distinct meteorites. The particular climatic and environmental conditions of Antarctica result in the recovery of a much larger fraction of the extraterrestrial material that falls to Earth than would be the case in other regions. Remarkable concentrations of meteorites are found in some ‘blue ice’ areas resulting from the movement and ablation of the ice. Most meteorites are believed to have been derived from asteroids less then 200 km in diameter. The discovery in Antarctica of meteorites of lunar material proved that other sources are possible. Indeed two meteorites from Antarctica may have come from the planet Mars. Antarctic meteorites have much older terrestrial ages than non-Antarctic specimens and may be used to obtain information on the movement of the ice sheets in the past.

Mosses have adapted to the Antarctic environment and are an ideal medium for studying plant resistance to abiotic stress. Chalcone synthase is the first committed enzyme in the flavonoid metabolic pathway, which plays an indispensable role in plant resistance to adversity. In this study, six genes (Pn021, PnCHS088, Pn270, PnCHS444, PnCHS768 and Pn847) were identified in the Antarctic moss Pohlia nutans Lindberg transcriptome by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). Sequence alignment and three-dimensional structure analysis revealed the conserved amino acid residues of the enzymes of the chalcone synthase family, including three catalytic residues (Cys164, His303 and Asn336) and two substrate recognition residues (Phe215 and Phe265). Phylogenetic analysis indicated that PnCHS088, PnCHS444 and PnCHS768 might be chalcone synthase but that Pn021 is more like stilbenecarboxylate synthase. These genes were located at the transition between fungi and advanced plants in the phylogenetic tree. In addition, real-time PCR analysis revealed that the expression profiles of the six P. nutans genes were influenced by diverse abiotic stresses as well as by abscisic acid and methyl jasmonate. The results presented here contribute to the study of the CHS gene family in polar mosses and further reveal the mechanisms underlying the adaptation of mosses to extreme environments.

New stable isotope and noble gas data obtained from fumarolic and bubbling gases and hot spring waters sampled from Deception Island, Antarctica, were analysed to constrain the geochemical features of the island's active hydrothermal system and magmatism in the Bransfield back-arc basin. The 3He/4He ratios of the gases (< 9.8 × 10-6), which are slightly lower than typical MORB values, suggest that the Deception Island magma was generated in the mantle wedge of a MORB-type source but the signature was influenced by the addition of radiogenic 4He derived from subducted components in the former Phoenix Plate. The N2/He ratios of fumarolic gas are higher than those of typical mantle-derived gases suggesting that N2 was added during decomposition of sediments in the subducting slab. The δ13C values of -5 to -6‰ for CO2 also indicate degassing from a MORB-type mantle source. The H2/Ar- and SiO2 geothermometers indicate that the temperatures in the hydrothermal system below Deception Island range from ~150°C to ~300°C. The δD and δ18O values measured from fumarolic gas and hot spring waters do not indicate any contribution of magmatic water to the samples. The major ionic components and δD-δ18O-δ34S values indicate that hot spring waters are a mixture of local meteoric water and seawater. Mn and SiO2 in spring waters were enriched relative to seawater reflecting water-rock interaction at depth.