The Scotia Arc, linking the Magellan region with the Antarctic Peninsula, comprises young and old islands both near continents and isolated, and is the only semi-continuous link between cool temperate and Antarctic environments. It is an ideal region for studies on how marine biodiversity changes across an extended transition zone. Echinoids (sea urchins) and their associated epibionts were found across depths from 91–1045 m, with 19 species from shelf and four from slope depths. The 23 species from 38 trawls represent 31% of all echinoid species known from the Southern Ocean and 38% of the shelf/upper slope echinoids. The specimens collected comprise representatives of the five families Cidaridae, Echinidae, Temnopleuridae, Schizasteridae and Pourtalesiidae. Echinoids are probably a good model for how well we know Antarctic shelf and slope megabenthos; none of the species we report are new to science but we found nine (39%) of our study species present at new localities, some thousands of kilometres from previous findings. New biogeographic ranges are illustrated for Ctenocidaris gigantea, C. nutrix, C. spinosa, Abatus curvidens, A. ingens, A. shackletoni, Amphineustes rostratus, Tripylaster philippi and Pourtalesia aurorae. Southern Ocean echinoids show eurybathy as the mean depth range of our study species was 1241 m and only one was at less than 500 m. The current view of echinoid dominance of super-abundance in the shallows seems to be not transferable to shelf and slope depths as only one of 38 trawls was dominated by echinoids. Current knowledge on maximum sizes in Antarctic echinoids seems to be good as our morphometric measurements were mainly within known size ranges. Regular echinoids increased predictably in mass with increasing test length, apart from Ctenocidaris spinosa. Tissue mass of cidaroid species was ~17%, but across irregular species varied from 17.7–8.9%. No epibionts were found on irregular echinoids or Echinidae but 70 cidaroids examined carried 51 species representing ten classes. Many of these species are reported as cidaroid epibionts for the first time. Cidaroids and their epibionts constituted > 38% of the total macrofaunal richness in the trawls they were present in. Echinoids and their epibionts clearly contribute significantly to Southern Ocean biodiversity but are minor components of biomass except in the shallows.

Age and diet of 140 brown phase early juvenile Notothenia rossii specimens caught at Potter Cove from December 2005–March 2006 were studied. Fish were immature, in the range 8.5–21 cm TL and of age groups 1–2 (otolith/scale readings). The diet (F% and coefficient Q methods) was mainly benthic-demersal organisms with Gammaridean amphipods (primarily Gondogeneia antarctica) as the most frequent (F% = 98) and main prey (Q% = 97). The occurrence of algae, gastropods and harpacticoid copepods was high, but these organisms were secondary or occasional food. The importance of other benthic (bivalves, polychaetes, isopods) and pelagic (ostracods, calanoids, hyperiid amphipods, krill) prey was very low. Preference of larger fish for larger prey was evident. Stomach fullness analysis showed high food availability during the sampling period. Young stages of N. rossii are demersal, preying mainly on gammarideans and other invertebrates of the benthic community associated with macroalgae beds. The almost complete lack of plankton components in the diet of early juvenile fish suggests they do not migrate vertically to feed.

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 presents horizontal and seasonal differences in the concentrations of nitrogen and phosphorus in the surface waters of Admiralty Bay. The average annual concentrations of total nitrogen and total phosphorus were found to be 1.054 and 0.129 mg dm-3 respectively. Organic nitrogen constituted 59% of total nitrogen on average, while N-NO3- was substantially higher than N-NH4+ (0.362 and 0.062 mgN dm-3, respectively). Organic phosphorus constituted 34% of total phosphorus on average, and the mean annual concentration of reactive phosphorus was 0.085 mgP dm-3. The observed concentrations of N and P were higher in the nearshore area and lower in the central part of the Admiralty Bay basin. In explaining this account was taken of surface runoff into the bay, the decay of marine macroalgae in the tidal area and the excretion of N and P by marine animals. The concentrations of total nitrogen and total phosphorus in freshwater streams varied from 0.528–5.698 mgN dm-3 and from 0.088–1.709 mgP dm-3. In laboratory experiments, 24-hour loads of total nitrogen and total phosphorus released from the remains of macroalgae into the waters of the bay were estimated at about 6.2 tN and 10.3 tP, while the approximate quantities excreted by macrozoobenthos were 482 kgN and 48 kgP. The availability of N-NH4+ was seen to be greater in the waters of the bay than has been reported for open water in this part of the ocean and water from the Bransfield Strait had a diluting effect on the concentrations of nitrogen and phosphorus in the bay. The role of the wind in carrying mineral salts from waters of the Bay to the inland environment was also discussed.

Several studies have been carried out during the last fifteen years on reproduction, population dynamics and diet of the Antarctic shag, Phalacrocorax bransfieldensis Murphy, at different localities in the South Shetland Islands (reviewed in Casaux & Barrera-Oro 2006). In both the colonies studied and in other colonies counted we observed that the number of breeding pairs was steadily decreasing (Casaux & Barrera-Oro 2006). Casaux & Baroni (2002) had earlier suggested that such a decreasing trend might be related, at least partially, to a marked decrease in the inshore populations of two fish prey species, the marbled notothen Notothenia rossii Richardson and the humphead notothen Gobionotothen gibberifrons Lönnberg (Barrera-Oro et al. 2000), which had been studied over a period of 19 years in coastal waters of the South Shetland Islands. Exactly how a reduction in prey availability affects the shag populations (e.g. migration of breeders to other colonies in the area or to new breeding areas, a decrease in the rate of recruitment, an increase in adult mortality, variation in the age at first breeding, etc) is not clear. To investigate this, we started a banding programme at Nelson Island, South Shetland Islands. We postulated that the processes might operate with different intensities on individuals of different sexes, so all individuals in each population studied needed to be sexed. This posed problems for chicks which have monomorphic plumage and no differences in vocalisations (Casaux & Baroni 2000), so that the normal methods for sexing in the field would not work. As most of the external morphological characters in the chicks of Antarctic shags have stabilized by 45–50 days old (Casaux 1998), Casaux & Baroni (2000) had suggested that the use of discriminant functions originally developed for adults could be an appropriate method to sex chicks more than 50 days old.

Recent trawling in the Southern Ocean has yielded individuals of a number of species of the deep sea octopod genus Thaumeledone. This paper provides the first molecular study of the genus, employing molecular sequences from five mitochondrial (12S rDNA, 16S rDNA, COI, COIII, cytochrome oxidase b) and a single nuclear gene (rhodopsin) and includes representatives of each of the known Southern Ocean species. Thaumeledone rotunda, believed to be circumpolar in distribution and found in relatively deep water is the sister taxa to T. gunteri, known only from South Georgia. A notable level of sequence variability was evident between a T. peninsulae individual recently captured from the Powell Basin, and two T. peninsulae individuals captured from the continental slope, north of the South Shetland Islands. This is likely to represent population level intraspecific variation within this species.

We surveyed south polar skuas (Catharacta maccormicki Saunders) in Antarctica for antibodies to a series of viral agents using blood serum and cloacal swabs from 124 adult skuas. There were no ticks on the subjects and we were unable to isolate virus from any individual. Skuas, however, were seropositive to some avian viruses: 16.9% (20/118) had antibodies to infectious bursal disease virus and 10.5% (11/105) were seropositive for Newcastle disease. We found 1.0% (1/98) had antibodies to avian influenza, no evidence of egg drop syndrome (0/48), but 27.8% (10/36) had antibodies to flaviviruses. Clearly south polar skuas encounter a variety of pathogens either in Antarctica or during their migration in the non-breeding season. There was no evidence of disease in skuas, but the presence of antibodies to pathogens indicates the need to continue to search for the origins of these immunological challenges.

A cadmium (Cd)-binding protein was isolated and characterized from the Antarctic clam Laternula elliptica after experimental exposure to a high concentration of Cd. Cd-binding metallothioneins (MTs) in the cytosol were purified using a procedure based on gel permeation and ion-exchange chromatography. The purified MTs were recognized by MT antibodies in a Western blotting assay. MALDI-TOF MS analyses showed that the molecular mass of the purified MTs was 7.27 kDa, which is typical of MTs found in marine invertebrates. The Cd binding to MT, reflected by the redistribution of Cd ions, was monitored by spectrophotometry. The absorption spectra profiles indicated the presence of Cd-MT complexes, and a 4 nm red shift of the unresolved lowest energy-absorption band occurred when five equivalents of Cd (II) were incorporated.

Pseudochaenichthys georgianus is a member of the unique Channichthyidae family of fishes, which lack haemoglobin. The distribution, length-frequency and summer diet are described from 14 bottom trawl surveys undertaken in the summers between 1986 and 2006. Pseudochaenichthys georgianus (50–590 mm TL) were caught throughout the South Georgia shelf from depths of 76–370 m, but very few specimens (< 1%) were caught on the Shag Rocks shelf. Multiple cohorts were present during each survey and length-frequency analysis of these cohorts suggests that growth is fast during the first 3–4 years. Stomach contents analysis (2005 & 2006) indicated that P. georgianus is a pelagic or semi pelagic predator, with the summer diet dominated by Antarctic krill (Euphausia superba). Fish (channichthyids and notothenids) were also taken, but were a relatively minor part of the diet.

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.

To survive in Antarctica, early explorers of Antarctica's Heroic Age erected wooden buildings and brought in large quantities of supplies. The introduction of wood and other organic materials may have provided new nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials. From 30 samples taken from Discovery Hut, 156 filamentous fungi were isolated on selective media. Of these, 108 were screened for hydrolytic activity on carboxymethyl cellulose, of which 29 demonstrated activities. Endo-1, 4-β-glucanase activity was confirmed in the extracellular supernatant from seven isolates when grown at 4°C, and also when they were grown at 15°C. Cladosporium oxysporum and Geomyces sp. were shown to grow on a variety of synthetic cellulose substrates and to use cellulose as a nutrient source at temperate and cold temperatures. The research findings from the present study demonstrate that Antarctic filamentous fungi isolated from a variety of substrates (wood, straw, and food stuffs) are capable of cellulose degradation and can grow well at low temperatures.

In an attempt to improve the understanding of the natural variability and distribution of trace elements in Antarctic organisms, the concentrations of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, vanadium and zinc in representative benthic species from two pristine coastal environments were measured and compared with literature data for other uncontaminated coastal ecosystems. Correlations between the elements, differences between the species and between the sampling sites were examined by principal component analysis. Metal accumulation was particularly evident in the tissues of the sea star Odontaster validus, the bivalve mollusc Laternula elliptica and in the red alga Phyllophora antarctica. However, metal accumulation was not the same for all the analytes, but, rather, depended on the organism characteristics. In particular, the soft tissues of Odontaster validus were characterized by high concentrations of cadmium, zinc and copper, those of Phyllophora antarctica by high concentrations of manganese and nickel, and the tissues of Laternula elliptica by high concentrations of all measured elements, particularly in its digestive gland. The Antarctic data as well as those reported for other pristine coastal ecosystems showed remarkably high natural variability in metal content, which must be taken into account when interpreting results from biomonitoring programmes.

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).

We analysed cytochrome oxidase I (COI) barcodes for 35 putative fish species collected in the Scotia Sea, and compared the resultant molecular data with field-based morphological identifications, and additional sequence data obtained from GenBank and the Barcode of Life Data System (BOLD). There was high congruence between morphological and molecular classification, and COI provided effective species-level discrimination for nearly all putative species. No effect of geographic sampling was observed for COI sequence variation. For two families, including the Liparidae and Zoarcidae, for which morphological field identification was unable to resolve taxonomy, DNA barcoding revealed significant species-level divergence. However, the dataset lacked sufficient sensitivity for resolving species within the Bathydraco and Artedidraco genera. Analysis of cytochrome b for these two genera also failed to resolve taxonomic identity. The data are discussed in relation to emergent priorities for additional taxonomic studies. We emphasize the utility of DNA barcoding in providing a valuable taxonomic framework for fundamental population studies through assigning life history stages or other morphologically ambiguous samples to parental species.

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.

Trematomus eulepidotus and T. loennbergii are two of the most common epibenthic fish in the waters of the High Antarctic continental shelf. Since the reproductive biology of these species has not been studied in the Ross Sea, we provide a macroscopic and histological analysis of the reproductive effort and gonadal development in both sexes. Most samples were collected during benthic trawl surveys in the south-western Ross Sea in the 1996 and 1997 summer seasons. The aim of the study was to define the reproductive characteristics of these two sympatric species and to examine the hypothesis that different reproductive strategies mitigate interspecific competition. We found that, in common with most Antarctic notothenioids, both species possess a suite of similar reproductive strategies including delayed sexual maturity, prolonged gametogenesis, group-synchronous oocyte maturation, a single spawning event per year and iteroparity. Both species show a comparable reproductive effort in terms of potential fecundity with between 2000 and 20 000 eggs per female per season. Nevertheless, the two species exhibited a considerable difference in the timing of the breeding season, spawning in summer (T. eulepidotus) and in autumn (T. loennbergii). This gives rise to a mismatch in the time of appearance of larvae in the environment and probably leads to reduced competition.

Limited sampling has so far been conducted of the meroplankton community of the high Antarctic, with most research being conducted using vertical hauls in waters > 50 m, and little focused research on the meroplankton community directly under the sea ice (cryopelagic). Here we report the composition of the early summer cryopelagic meroplankton community of the shallow waters of Gerlache Inlet, Terra Nova Bay. A fixed-frame stationary plankton net was deployed c. 1 m below the annual sea ice and sampled at c. 24 hour intervals over a period of 19 days from mid-November to early December 2006. A total of 173 larvae from the phyla Annelida (n = 66), Mollusca (n = 30), Nemertea (n = 4), Echinodermata (n = 8), several Pleuragramma antarcticum (n = 4) and numerous planulae (n = 61) were collected, as well as 265 egg/embryo stages. A mean of 9.1 larvae (SD = 7.3, n = 19) and 13.9 eggs/embryos (SD = 20.5, n = 19) were found directly below the sea ice in each 24 hour period, and these early life history stages may be subject to the hazards of extensive platelet ice and penetrating ultraviolet radiation. The cryopelagic meroplankton community of shallow water is also compositionally similar to that of deeper waters, suggesting that the 50–0 m plankton tows used in previous research are providing a reliable assessment of the biodiversity of coastal Antarctic meroplankton.

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.

The clay mineralogical composition of a 552 cm long sediment core from Lake Terrasovoje in Amery Oasis, East Antarctica, was analysed and compared with that in surface sediments from other locations in the vicinity. The lower part of the sediment core is formed by sub- and proglacial sediments with a dominance of smectite and illite, and lower amounts of kaolinite and chlorite. The upper part of the core is deposited after 12 500 cal yr bp and mainly composed of illite and kaolinite, with low amounts of smectite and chlorite, such as found in samples from rock outcrops and covering sediments throughout Amery Oasis. The clay composition in the lower section of core Lz1005 suggest that the basin of Lake Terrasovoje was filled by a 150–200 m thickened Nemesis Glacier prior to 12 500 cal yr bp rather than by local ice caps.

Abundance and grazing impacts of krill, salps and herbivorous copepods were investigated in Antarctic waters along the 140°E meridian, south of Australia, during the summers of 2002 and 2003. North of the Southern Boundary of the Antarctic Circumpolar Current (SB-ACC), macrozooplankton comprised species of Salpa thompsoni and large herbivorous copepods, while the area south of the SB-ACC was numerically dominated by Euphausia superba or E. crystallorophias. North of the SB-ACC, the estimate of grazing impact revealed that krill, salps and copepods, Calanoides acutus, Calanus propinquus, Rhincalanus gigas and Metridia gerlachei, are able to remove a maximum of 37% of the total phytoplankton standing stock in early to midsummer, but grazing is negligible in late summer. The high grazing impact is attributed to the relatively high zooplankton abundance and low phytoplankton abundance. South of the SB-ACC, overall daily grazing impact of the three zooplankton groups was low and did not exceed 6% of the total phytoplankton standing stock throughout the investigation period. Present results indicate that the contribution of krill, salps and copepods varies seasonally as well as regionally across the SB-ACC. It seems that the carbon transport from surface to deep water by macro- and mesozooplankton in summer in this area is relatively large north of the SB-ACC but small south of the SB-ACC.