The composition of suprabenthic Peracarida from a depth between 1 and 1.33 m above the seafloor was investigated. In order to study the abundance and diversity quantitatively, the samples were taken by means of the supranet of an epibenthic sledge off Kapp Norvegia and off the South Shetland Islands. The samples were taken during ANT XVII-3 with RV Polarstern in April and May 2000. These samples of EASIZ III received during the Antarctic autumn are compared with those of EASIZ II taken during the summer. While the autumn samples show far less abundance of all peracarid taxa, the diversity is about twice as high as during summer. In total 115 species of peracarid crustaceans were sampled at six stations yielding 1336 individuals standardized to 1000 m3 hauls. Amphipoda clearly dominated in abundance and diversity.

A review of the collembolan fauna of the South Shetland Islands is presented. Cryptopygus nanjiensis Yue & Tamura is synonymized with C. antarcticus Willem. A record of Tullbergia mediantarctica Wise from King George Island is considered a misidentification of Tullbergia mixta Wahlgren and Tillieria penai Weiner & Najt, described from the same island, is synonymized with T. mixta. The current fauna stands at eleven species, of which at least three are introduced. A checklist of Collembola currently considered to occur in the South Shetland Islands is supplied with distributional data.

Several sub-Antarctic penguin populations have exhibited decreasing trends in the last 5–20 years. At Iles Kerguelen, the gentoo penguin (Pygoscelis papua) has decreased by approximately 30% over the last 15 years. This decrease is likely to be related to reduced food availability for this coastal species. We discuss this decrease with regard to the impact of overfishing and to the potential effects of climate changes on marine food webs.

A total of 135 bacterial strains were isolated from congelation (land fast) sea ice samples and ice algae biomass samples obtained from the coastal areas of the Vestfold Hills in East Antarctica (68°S, 78°E) during the summers of 1992–95. The sea ice isolates, along with reference strains. were analysed by numerical taxonomy and for DNA base composition in order to determine the biodiversity of sea ice bacteria. From these analyses 22 clusters of strains (phena) were obtained with most phena apparently representing novel bacterial taxa. The sea ice isolates could be categorized into three groups based on their ecophysiology: 1) slightly halophilic, psychrophilic bacteria often possessing fastidious growth requirements and which were predominantly isolated from sea ice algae biomass or from algae-rich ice samples; 2) halotolerant and psychrotolerant bacteria; and 3) non-halophilic bacteria isolated primarily from upper sections of congelation ice and other ice samples with low levcls of algal biomass.

Surface-based observations were taken of cloud and precipitation particles on the Avery Plateau (66°50.34′S 65°29.58′W), Antarctic Peninsula from 25 November to 13 December 1995. This paper considers cloud parameters on three days during this period when the cloud base reached ground level and snow was falling. It was found that on all three days more ice crystals were present in the cloud than would be expected from simple theoretical considerations. The rate of snowfall decreased as the number of ice crystals increased, the large number of ice crystals present effectively suppressing the formation of large precipitation-sized crystals. The source of the ice nuclei that allowed the formation of the large number of crystals is not known for certain but is thought to be the snow surface, possibly in the form of very fine ice crystals blown from the surface during blowing/drifting snow episodes.

By considering the basic stress equations for a unit volume of ice, a set of differential equations describing ice shelf flow is derived. In view of the lack of basal shear stresses at the bottom of ice shelf a model simulation which is restricted to the horizontal dimensions will not imply substantial errors. The model is applied to the Filchner-Ronne Ice Shelf, Antarctica, and model equations are solved in terms of finite differences on a 10 × 10 km grid. Present ice thickness data and boundary conditions, i.e. the balance velocities at the grounding line and strain rates at the ice front are entered as input. Using a non-linear Glen-type flow law (n=3) and a constant depth-averaged flow law parameter, representing an ice temperature of −17°C, a convincing velocity field is derived as a solution of the model equations. The model takes into account restrained flow across ice rumples where sufficient field data are available. A diagnostic run reproducing present velocity magnitudes is followed by two prognostic runs, each representing 2000 years of simulation. Transient ice thickness changes are obtained from solving the mass conservation equation. Two different assumptions concerning basal melting rates demonstrate its importance to ice shelf dynamics. Assumptions are: a) no basal melting, b) basal melting rates (−2m a−1 to +3m a−1) as derived from model results and geophysical field data.

Measurements of dissolved N2, O2, Ar, CO2, and CH4 were made in perennially ice-covered Lake Hoare. Results confirm previous reports that O2 concentrations in the upper water column exceed atmospheric equilibrium and that N2 and Ar are supersaturated throughout the water column. The mean supersaturation of N2 was found to be 2.0 (±0.37) and Ar was 3.8 (±1.1). The ratios of N2/Ar (20.3 ±3.8), and O2/Ar (22.5 ±4.0) at the ice-water interface are consistent with those previously measured, suggesting that bubble formation is the main process for removing gas from the lake. However, the saturations of N2 and Ar greatly exceed those previously predicted for degassing by bubble formation only at the ice-water interface. The data support the hypothesis that removal of gas by bubbles occurs in the water column to a depth of 11 m in Lake Hoare. CO2 concentration increases from near zero at the ice-water interface to 80–100 times saturation at and below the chemocline at c. 28 m. There is considerable variability in the gas concentrations throughout the water column; samples separated in depth by one metre may vary by more than 50% in gas content. It is likely that this phenomenon results from the lack of turbulent mixing in the water column. Methane (c. 2 μg 1−1) was detected below the chemocline and immediately above the sediment/water interface at a depth of 30 m. Samples from lakes Vanda, Joyce, and Miers, also show supersaturations of O2, N2, and Ar at levels similar to levels found in Lake Hoare.

The Sørsdal Formation and one member, Graveyard Sandstone Member constitute a sedimentary sequence covering approximately 10 km2 of Marine Plain, Vestfold Hills, East Antarctica. The new Formation consists dominantly of friable diatomaceous siltstone and sandstone with dark limestone lenses. It is in situ, essentially horizontal, 7.2 m thick in its type section and lies less than 25 m a.s.l. Graveyard Sandstone Member occurs near the top of the formation, is highly lithified sandy diamictite, 30–50 cm thick and widespread through the Marine Plain region. Using diatoms, the Formation is Early Pliocene in age (Fragilariopsis barronii, 4.5–4.1Ma). The Graveyard Sandstone Member probably was deposited during the Gilbert Chron interval (lower Chron 2Ar or C3n. 1r) of reversed magnetic polarity. The Sørsdal Formation contains fossil cetaceans and a diverse and well-preserved invertebrate fauna. Foraminifera are rare partly because of diagenesis, but include Ammoelphidiella antarctica. No evidence of coeval terrestrial vegetation has been recovered. The deposit accumulated in a series of small bays probably in an environment warmer than exists in the region today. There is no lithological evidence of glacial influence except in Graveyard Sandstone Member that may represent local glacial influence in a shallow marine to intertidal environment.

The notothenid species Trematomus bernacchii has previously been shown, by allozyme analysis, to be a complex of two cryptic species, one of which being more closely related to T. hansoni than to the other T. bernacchii cryptic species. Two T. bernacchii colour morphs, “white blotch” and “brown”, at McMurdo Sound, may correspond to these cryptic species. In this study, we present mitochondrial DNA sequences of the 12S and 16S ribosomal regions for six “white blotch” morphs, eight “brown” morphs collected in McMurdo Sound, one individual collected off the Antarctic Peninsula, and two T. hansoni individuals from McMurdo Sound. These sequences were compared with those of T. bernacchii and T. hansoni in the literature. Based on 14 phylogenetically informative sequences, no differences were found between “white blotch” and “brown” morphs. Furthermore, only one substitution separated these sequences from the previously published T. hansoni sequence, while 10 substitutions separated them from the previously published T. bernacchii sequence. Misidentified specimens, and sequence misreadings may be at the origin of these discrepancies. However, the presence of cryptic species within T. bernacchii and T. hansoni is not ruled out.

The diurnal vertical distribution and abundance of fish larvae was studied by net samples in the 265 m deep fjord of Cumberland East Bay, South Georgia. In early spring the six most abundant species of fish larvae in the upper 200 m of the water column were Champsocephalus gunnari, Lepidonotothen nudifrons, Pseudochaenichthys georgianus, Chaenocephalus aceratus, Parachaenichthys' georgianus and Electrona antarctica. In summer, the larvae of C. gunnari, Gobionotothen gibberifrons, Lepidonotothen larseni and Trematomus hansoni were most abundant, and the majority were found in the upper 140 m of the water column, with greatest densities in the top 2m. During both seasons most species showed some evidence of diurnal vertical migration. A distinct pattern was found for C. gunnari in summer; they were at 0–20 m during the day and 60–100 m at midnight. Net avoidance by the larvae of most species was greater before sunset in early spring, and during all periods of daylight in summer, than at other times of day.

Zooplankton was sampled intensively with an RMT 1+8M system in the fjord of Cumberland East Bay, South Georgia during late winter 1983 and summer 1987. In summer, biomass was highest in the surface 20 m, reaching 142 g dw/1000 m3. Copepods dominated the zooplankton comprising 96–99% by numbers, of which 80–90% occurred in the top 100 m of the 265-m water column. The small clausocalanid Drepanopus forcipatus was particulary abundant. With increasing depth the proportion of non-copepod biomass, principally Mysidacea and Amphipoda increased significantly. Biomass throughout the water column in winter was generally 4–5 times lower than in summer although again copepods, and in particular D. forcipatus and members of the Metridinidae, still numerically dominated the plankton. Biomass levels were some 2–3 times greater than those found in Antarctic oceanic regions but were comparable with estimates from some boreal fjords. The mixture of neritic and oceanic species encountered, and the seasonal presence of some gelatinous zooplankton, particularly ctenophores, appears typical of the community structure of many fjord ecosystems.

During the summer 2005/06, an oceanographic cruise was carried out in the Ross Sea, from Cape Adare, through the Terra Nova Bay polynya to the eastern edge of the Ross Ice Shelf. We analysed microbial activities (prokaryotic carbon production, protease, phosphatase, beta-glucosidase and lipase activity) and bacterial community structure (using Denaturing Gradient Gel Electrophoresis - DGGE) in order to establish if differences in bacterioplankton assemblages and their metabolic requirements occur within the five Ross Sea water masses: Antarctic Surface Waters (AASW), High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW), Antarctic Bottom Water (AABW), Circumpolar Deep Water (CDW). Differences in activities were found between the highly active AASW and all the other water bodies. A Principal Component Analysis highlighted two main gradients: in the Cape Adare area (AASWn, CDW and AABW) higher phosphatase, lipase and glycolytic activities, increasing towards the surface, were identified, whereas in the southern sector of the basin [AASWs and (m)HSSW] higher leucine uptake and polypeptide degradation characterized the second gradient. DGGE fingerprinting showed for the first time that different water masses harboured diverse bacterial communities, highlighting the high specificity of deep water assemblages. Alpha- and Gammaproteobacteria represented the main phylogenetic groupings in all samples and no substantial difference in the phylogenetic composition of assemblages was found between different water masses.

A radioecological survey around Terra Nova Bay showed that 239 + 240Pu, 238Pu, 241Am, 90Sr and 137Cs activities were detectable in nearly all the samples. The 239 + 240Pu and 241Am concentrations in seawater were slightly lower than those in the northern Pacific Ocean. The activity level of 239 + 240Pu, 241Am and 137Cs in Antarctic sediments (Ross Sea) was c. 5–20 times lower than in northern Adriatic sediments (Mediterranean Sea), but the 238Pu activities were relatively high. The 90Sr concentrations in all the sediment samples from both the Ross and Adriatic seas tended to be low which might be due to an easier exchange of 90Sr in seawater. On the other hand, high concentrations were detected in Antarctic mosses, lichens and algae and their activity levels are comparable to those in central Italy. The radionuclide ratio analyses show that the major part of 239 + 240Pu, 241Am, 90Sr and 137Cs is the result of nuclear weapon tests. A higher 241Am/239 + 240Pu ratio might be due to the fallout of earlier atmospheric nuclear tests. The 238Pu239 + 240Pu ratio in the Antarctic matrices is about seven times higher than in the Northern Hemisphere and this could suggest that the major part of 238Pu originated from the SNAP-9A satellite accident.

The Jurassic plant fossil record of Gondwana is generally meagre, which renders phytogeographic and palaeoclimatic interpretations difficult to date. Moreover, plant fossil assemblages mainly consist of impressions/compressions with rather limited palaeobiological and palaeoecological significance. We here present a detailed survey of new Early Jurassic plant assemblages from the Pliensbachian Shafer Peak Formation, north Victoria Land, Transantarctic Mountains. Some of the well-preserved fossils yield cuticle. The floras consist of isoetalean lycophytes, sphenophytes, several ferns, bennettitaleans, and conifers. In addition, three distinct kinds of conifer shoots and needles were obtained from bulk macerations. The composition of the plant communities is typical for Jurassic macrofloras of Gondwana, which underscores the general homogeneity of Southern Hemisphere vegetation during the mid-Mesozoic. Altogether, the plant fossil assemblages indicate humid and warm temperate conditions, which is in contrast to recent palaeoclimatic models that predict cool temperate climates for the continental interior of southern Gondwana during the Jurassic. However, there is no evidence for notable soil development or peat accumulation. The environmental conditions were apparently very unstable due to intense volcanic activity that resulted in frequent perturbation of landscape and vegetation, hampering the development of long-lived climax communities. Cuticles of bennettitaleans and conifers show xeromorphic features that may have been beneficial for growth in this volcanic environment.

A shark tooth from the Spartan Glacier Formation of the Fossil Bluff Group of Alexander Island, Antarctic Peninsula is described and assigned to Palaeospinacidae, an extinct group of neoselachian sharks. This tooth was previously supposed to have been recovered from Middle Jurassic strata and to belong to Hybodus. However, sedimentation of the Spartan Glacier Formation was from the Valangian to Aptian. Consequently, an Early Cretaceous age is assigned to the specimen although its exact stratigraphical horizon is unknown. A generic assignment, however, is not possible although it may belong to Paraorthacodus. This specimen represents the first record of a neoselachian from the Early Cretaceous of Antarctica.

It has been demonstrated that persistent organic pollutants (POPs) can affect the immune system of mammals and birds. In this study, the concentration of different POPs and leukocytes in blood samples from three chinstrap penguin (Pygoscelis antarctica) populations was analysed in order to assess the impact on haematological parameters. Using blood sample smears, basophils, eosinophils, heterophils, lymphocytes and monocytes were quantified. Mature and immature red blood cells were counted and cell alterations in both white and red blood cells were analysed. At the same time, whole blood was analysed for POPs. The results showed that contaminants, such as dichlorodiphenyltrichloroethane and its metabolites (ΣDDT), as well as polychlorinated biphenyls (ΣPCB), had significant correlations to eosinophils, lymphocytes and heterophils. This indicates possible immunohaematological alterations derived from exposure to such contaminants. Cytological alterations were also observed, such as cytotoxic granules, toxic heterophils, and atypical and granulated lymphocytes, which would demonstrate that these seabirds are being exposed to stress agents that could be producing some alterations at a leukocytary cellular level.

George VI Ice Shelf is the largest ice shelf on the west coast of the Antarctic Peninsula, covering a total area of 25 000 km2. The northern ice front of George VI Ice Shelf presently marks the southernmost occurrence of recent ice-shelf retreat on the Antarctic Peninsula and according to some predictions the ice shelf is close to its thermal limit of stability. If these predictions are accurate and we are witnessing the first stages of retreat then it is critical that we take the opportunity to examine the ice shelf in its pre-collapse phase. This paper provides a review of the geological evolution, glaciology and interactions between the ocean and the atmosphere. We also discuss the present behaviour of the ice shelf, in the context of recent retreat of its northern and southern ice fronts, and outline several possible mechanisms for future ice shelf collapse. What emerges from this review is that the stability of George VI Ice Shelf is sensitive not only to the recent rapid regional atmospheric warming on the Antarctic Peninsula which has led to the gradual retreat of the northern and southern ice shelf fronts, but also to changes in ocean circulation, particularly intrusions of warm Upper Circumpolar Deep Water onto the continental shelf. It is likely that any future change in the stability of George VI Ice Shelf will involve a combined atmospheric and oceanic forcing.

An analysis of a long-term surface air temperature record for Fossil Bluff in the George VI Sound, West Antarctic Peninsula (WAP) documents in detail some important aspects of the climate of this area for the first time. The analysis identifies the close dependency of air temperatures on latitude in the WAP but reveals that the strength of this dependency is greatest in winter. This result along with others leads to the Fossil Bluff climate regime being characterized as ‘continental’ rather than ‘maritime’ as found further north. The WAP as a whole displays large interannual temperature variability but this is greatest in Marguerite Bay rather than the Fossil Bluff area. Evidence is also provided for secular climatic change appearing in summer throughout the WAP over the last few decades. The representativeness of existing Antarctic Peninsula annual air temperature climatologies, based mainly on snow temperature measurements, for the winter and summer periods is also noted.

The distribution of dimethylsulphide (DMS), together with the precursor dimethylsulphonio-propionate (DMSP) and the oxidation product dimethylsulphoxide (DMSO), was measured in melt waters on the McMurdo Ice Shelf in the immediate vicinity of Bratina Island. Conductivity in these sulphate dominated ponds was extremely variable, ranging from 0.106–52.3 mS cm−1. Similarly, chlorophyll a concentrations in the pond waters (1–150 μg 1−1) and mats (1.4–33 μg cm−2) differed considerably. The biomass was dominated by benthic felts of phototrophic cyanobacteria, which might act as a source of biogenic sulphur compounds in the ponds. The mean (and ranges) of concentrations of dissolved sulphur compounds (nmol 1−1) were: CS2 0.16 (<0.04–1.29); DMSPd 0.6 (<0.07–8.4); DMS 3.5 (<0.07–183); DMSO 27.9 (15.5–184.5). Very high concentrations of DMSO were ubiquitous in the ponds in the ice-cored moraine region of the ice shelf, with dissolved concentrations having been 1–2 orders of magnitude greater than those of DMS or DMSPd. It is difficult to ascribe the formation of DMSO solely to the conventionally accepted pathways of DMS oxidation by either bacterial activity or photochemical reactions. A direct biosynthetic production from phytoplankton or bacteria might be involved which means that DMSO in aquatic environments could act as a significant source of DMS rather than as a sink as generally supposed.

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.