We present geochronological and geochemical data for eight plutonic rocks from five locations in the Pine Island Bay area of West Antarctica, collected during RV Polarstern expedition ANT-XXIII/4. Ar-Ar laser method dating yielded closure temperatures ages of c. 147–98 Ma for dioritic and granitic plutonic rocks and an age range of c. 97–95 Ma for granitoid and trachyandesitic dykes. Major and trace element compositions indicate that all rocks have an I-type subduction-related chemistry. There are no A-type granitic rocks in our dataset, and none are yet reported from the Pine Island Bay area. Our results confirm earlier models of post 100 Ma subduction on this part of the Gondwana margin.

Data on the response behaviour of seals (crabeater, leopard and Ross) and penguins (Adélie and emperor) to helicopter surveys over the pack ice off East Antarctica are presented. The surveys involved Sikorsky S76 helicopters flying at altitude 130 m and speed 90 knots along straight-line transects. The relative frequency of alert and movement behaviours by seal and penguin groups decreased with distance out to 800 m from the flight path. Penguin groups were more likely to show a movement response than seals at all distances. The perpendicular distances moved relative to the flight path were small (maximum 20 m, mean ≤ 3 m, for both seal and penguin groups) relative to the width of the area searched (800 m), and there was no evidence that response movement resulted in a spiked detection histogram. Observers were more likely to feel confident in identifying seal and penguin species if the animals responded to the helicopter by changing the body posture or moving. In this application of aerial survey, the response behaviour elicited by the passing helicopter was considered to be beneficial from a technical perspective, and the disturbance caused to the surveyed populations negligible from an ethical perspective.

In this paper we report the first characterization of cultivable bacteria obtained from the Antarctic sea urchin Sterechinus neumayeri. The coelomic fluid was obtained from a pool of sea urchins which was plated onto different media to isolate the bacteria. A total of 42 isolates of psychrotrophic and aerobic γ-Proteobacteria (59.5%), Flavobacteria (33.3%) and Actinomycetes (7.2%) were isolated and sequenced. These bacteria were exposed to heavy metals and antibiotics, where 38 strains were analysed by the minimal inhibitory concentration method. Antibiotic resistance was detected in 44% of cultivable strains, and a further 13% presented co-resistance to antibiotics and heavy metals. The genera of bacteria that showed an increased resistance and co-resistance to metals and antibiotics were Flavobacterium, Psychrobacter and Pseudomonas. Additionally, 30.9% of isolated bacterial strains contained plasmids, which are probably related to resistance and co-resistance to metals. These results indicate that sea urchin-associated bacteria could be reservoirs for antibiotic resistance genes.

This paper reports on sightings and dispersion of individual southern elephant seals (Mirounga leonina) along the Atlantic and Pacific coasts of South America based on reports of tagged/marked seals from Patagonia and of animals of unknown origin. From 154 sightings, encompassing at least 354 individuals, we found that individuals dispersed to subequatorial latitudes on both sides of the continent, and to more temperate sites, in the Magellanic region of Tierra del Fuego. Nineteen sites were visited by tagged seals from the established colony of Península Valdés (PV, Argentina). PV and the smaller seal population of the Falklands/Malvinas were regularly connected by adults of both sexes. There were more sightings of males than females. No incipient new breeding colonies were found along the Atlantic coast of South America. Some observations coincided with places where elephant seals had been recorded or exploited in the seventeenth and eighteenth centuries. A shortage of suitable habitat for expansion and proximity to predictable food could act as a stabilizing process preventing colonization of new areas from PV. Dispersion data, coherent with population genetics, support a Patagonian elephant seal stock.

Following the break-up of Gondwana, the drift of Antarctica to its present position and the establishment of the Antarctic Convergence, fish evolution was characterized by adaptation to progressive cooling of the environment. The decrease of erythrocyte number and haemoglobin concentration in the blood of Antarctic teleosts raises several questions concerning the physiology of respiration and the enzymatic role of erythrocytes. Our study of the molecular basis of cold adaptation includes the relationship between molecular structure and biological function of haemoglobins. Species of the suborder Notothenioidei, largely confined within the Convergence, have only one major haemoglobin, which displays the Root effect in oxygen binding; on the other hand, Zoarcidae (a family found at all latitudes) have four or five haemoglobins, only one of which displays the Root effect. In addition, our data indicate that the physiological relevance of erythrocyte-like cells, present in very small number in the blood of haemoglobinless Channichthyidae, may be linked to higher content of enzymes, such as glucose-6-phosphate dehydrogenase, in comparison with erythrocytes of red-blooded fishes.

Plant megafossils collected from the previously unexplored English Coast of eastern Ellsworth Land have yielded the first Glossopteris leaves from the Antarctic Peninsula tectonic province. Collecting at Erehwon Nunatak recovered numerous spatulate leaves of consistent morphology, most likely pertaining to one natural species, and described here as Glossopteris erehwonensis sp. nov., as well as fragments of Phyllotheca and Equisetum. The large sample size, the predominance of Glossopteris leaves, the low species diversity, and the lack of characteristic Early Permian (Gangamopteris) and Early Triassic (Dicroidium, Lepidopteris, Pleuromeia) taxa suggest a Permian, probably Late Permian, age for the Erehwon Nunatak beds. These rocks are thus significantly older than any other sedimentary rocks known from Palmer Land and Ellsworth Land. A second flora, collected from Henkle Peak, consists exclusively of the remains of Elatocladus planus, a conifer which probably dominated forests in this area during the Jurassic. The plant megafossils support correlation of the sedimentary rocks with those of the Middle–Late Jurassic Latady Formation of south-eastern Antarctic Peninsula and eastern Ellsworth Land.

Currently, a substantial proportion of Antarctic research is carried out through deployment of field camps, but little detailed information on the running of these facilities is often available. The remoteness of camps and the fragility of local Antarctic terrestrial ecosystems make the running of sustainable, low impact field science and logistics in ice-free areas a challenge for environmental managers. In this study we examined the environmental management at the Spanish camp within Antarctic Specially Protected Area (ASPA) No. 126 Byers Peninsula, Livingston Island, South Shetland Islands. Firstly, the input of materials and generation of pollution associated with the camp during a ten year period of operation was quantified. Examination of greenhouse gas emissions shows a mean of 14 t CO2 equivalent per researcher associated with transportation of people to the site, plus 44 t CO2 equivalent per researcher, associated with transportation of cargo to the field site. Secondly, the cumulative trampling footprint across Byers Peninsula and associated local impacts were recorded. Results showed the pattern of human movement within the ASPA and how activities concentrated around the field camp site. At the same time every effort was taken to ensure scientific outputs from research activities within the ASPA were maximized. Practical recommendations on operational logistics are discussed to minimize environmental impacts and optimize scientific benefits.

Measurements of humidity at a height of 4 m were made at Halley Research Station between 1995 and 1997 using a frost point hygrometer. Relative humidities were usually close to ice saturation, particularly during the winter, but ice supersaturations of up to 20% were frequently measured. Supersaturation with respect to liquid water was rarely observed. During the summer, diurnal variation in temperature drove a daily cycle in relative humidity, although corresponding variations in mixing ratio were comparatively small. It is suggested that the high frequency of ice supersaturations and almost total absence of water supersaturation results from the high abundance of condensation nuclei relative to ice nuclei.

Bacterial cultures obtained through selective enrichment of beach sand collected 60 days and one year after treatment of sites in a pilot oil spill trial conducted at Airport Beach, Vestfold Hills, East Antarctica, were examined for the ability to degrade n-alkanes and phenanthrene. The effects of different hydrocarbon mixtures (Special Antarctic Blend [SAB] and BP-Visco), fish oil [orange roughy]) and inoculation of replicate sites with water from Organic Lake (previously shown to contain hydrocarbon-degrading bacteria) on the indigenous microbial population were examined. Of the cultures obtained, those from sites treated with SAB and BP-Visco degraded n-alkanes most consistently and typically to the greatest extent. Two mixed cultures obtained from samples collected at 60 days and two isolates obtained from these cultures extensively degraded phenanthrene. 1-Hydroxy-naphthoic acid formed the major phenanthrene metabolite. Lower levels of salicylic acid, 1-naphthol, 1, 4-naphthaquinone and phenanthrene 9-10 dihydrodiol were detected in extracts of phenanthrene grown cultures. This study shows that under laboratory conditions indigenous Antarctic bacteria can degrade n-alkanes and the more recalcitrant polycyclic aromatic hydrocarbon, phenanthrene. The enrichment of hydrocarbon degrading microorganisms in Antarctic ecosystems exposed to hydrocarbons is relevant for the long term fate hydrocarbon spills in this environment.

A low diversity plant macrofossil assemblage described from the northern section of Fossilryggen, Vestfjella, Dronning Maud Land, Antarctica, is dominated by matted leaf impressions of Glossopteris sp. cf. G. communis Feistmantel and Glossopteris sp. cf. G. spatulata Pant & Singh, and in situ finely branched Vertebraria indica Royle rootlets. Equisetalean stems, rhizomes and leaf whorls (Phyllotheca australis Brongniart emend. Townrow), isolated seeds, scale-leaves, and fragmentary gymnosperm axes represent minor components of the assemblage. The fossils are preserved in fine-grained, floodbasin sediments and dark palaeosols. Although lacking definitive biostratigraphical indices, the flora is considered to represent a Middle Permian assemblage based principally on lithological and palynological correlation with the southern section at Fossilryggen and broad similarities to mid-Permian plant assemblages elsewhere in Gondwana.

Satellite transmitters were attached to eight adult spectacled petrels Procellaria conspicillata Gould captured during the early incubation period at their breeding grounds on Inaccessible Island, one of the Tristan da Cunha Islands in the central South Atlantic Ocean. Data on their at-sea distribution was obtained for up to six months. All birds remained within the South Atlantic from 24–44°S, with most between 25 and 40°S. Breeding birds mainly foraged in oceanic waters, but failed breeders or non-breeders concentrated their foraging activity over the Rio Grande Rise and the Walvis Ridge and along the shelf break off the east coast of South America. Little foraging occurred along the Benguela shelf break off southern Africa. Non-breeders favoured relatively warm water with low chlorophyll concentrations, reducing the risk of bycatch in fisheries. Tracked birds spent 16% of their time in areas with high levels of tuna longline fishing activity, with overlap greater for non-breeding birds (22%) than breeding birds (3%). Birds in this study foraged in shallower waters along the continental shelf edge off South America than spectacled petrels tracked in this area in winter, potentially increasing their risk of exposure to demersal longline fisheries in this area in summer.

Physically weighing large marine mammals sequentially over time has presented researchers with a logistical challenge and has severely limited sample sizes. Using a well-established photogrammetry method we developed a simple mathematical method to calculate accurate mass measurements at specific stages in the life cycle of a top marine predator. Female southern elephant seals (n = 23) at Marion Island were sampled sequentially using photogrammetry and three-dimensional models (based on each photogrammetry project) were built for estimation of body mass. Simple equations were applied to obtain mass at critical instances in their life cycle. Marion Island elephant seal mass data was compared to data obtained from physically weighed elephant seals from King George, South Georgia and Macquarie islands. Females from Marion Island are smaller, but their percentage lactation mass loss is similar to females from these other populations. The similarity of percentage mass loss during lactation between different female populations illustrates the accuracy and practicality of the photogrammetric method over a temporal scale. Photogrammetric mass estimation can be used alongside datasets of physically weighed animals and can greatly benefit ecology and life history studies.

A total of 69 diatom taxa, belonging to 24 genera were recorded from thirteen freshwater and moss samples collected in the Antarctic Peninsula region. Marine taxa comprised 26%. Cluster analysis revealed three assemblages. The Nitzschia acidoclinata assemblage occurs on wet mosses; the Luticola muticopsis assemblage is found near penguin rookeries whereas the Pinnularia krookii–Pinnularia microstauron var. elongata assemblage occurs on drier places such as dry mosses and drying mud.

Properties of the surface and bottom circulation in the north-west Weddell and south Scotia seas in the region 59–66°S, 36–46°W are examined. The bottom currents have been recorded at different heights from 5–800 m above the seabed, and surface velocities have been obtained from the drift tracks of ARGOS buoys deployed in ice floes. The tidal regime is mixed and the power of motions at inertial frequencies is very variable and most dominant in the Scotia Sea. Flow is influenced by topography, effects of which are seen in eddy features and the damping of inertial motions in some areas. The sea ice motion is shown to be influenced by the bottom topography at very low frequencies whilst tidal periodicities observed in the north-western Weddell Sea are below the level of the noise in the region of the study. In this area the higher frequency ice motion is mainly wind driven with little of the energy being transferred to the underlying deep water.

The biota of Antarctica is amazingly rich and highly endemic. The phylogenetics of notothenioid fishes has been extensively investigated through analyses of morphological characters, DNA sequences from mitochondrial genes, and single copy nuclear genes. These phylogenetic analyses have produced reasonably similar phylogenetic trees of notothenioids, however a number of phylogenetic questions remain. The nototheniid clade Trematomus is an example of a group where phylogenetic relationships remain unresolved. In this paper we revisit the phylogenetic relationships of Trematomus using both increased taxon sampling and an expanded dataset which includes DNA sequences from two mitochondrial genes (ND2 and 16S rRNA) and one single-copy nuclear gene (RPS7). The Bayesian phylogeny resulting from the analysis of the combined mitochondrial and nuclear gene datasets was well resolved and contained more interspecific nodes supported with significant Bayesian posteriors than either the mitochondrial or nuclear gene phylogenies alone. This demonstrates that the addition of nuclear gene sequence data to mitochondrial data can enhance phylogenetic resolution and increase node support. Additionally, the results of the combined mitochondrial and nuclear Bayesian analyses provide further support for the inclusion of species previously classified as Pagothenia and Cryothenia in Trematomus.

Satellite infra-red imagery and meteorological data suggest the presence of winter open water (polynya) in the coastal pack ice to the north and west of the Brunt Ice Shelf. Satellite imagery, although only available for a limited number of occasions, provides evidence for the polynya during the austral winter of 1991. Indirect meteorological observations from the British Antarctic Survey's Halley station (75° 36′S, 26° 42′W) provide very strong supporting evidence of open water to the west of the ice shelf in previous years.

A preliminary palynological study of Beacon Supergroup sedimentary rocks exposed at Milorgfjella, Dronning Maud Land, has yielded a relatively rich and well preserved palynoflora dominated by spores and pollen grains, but also including acritarchs and green algae. The palynoflora is dominated by the pterophyte spores Punctatisporites gretensis, Punctatisporites parvus, Granulatisporites spp., Microbaculispora tentula Horriditriletes spp. and Verrucosisporites andersonii, and the gymnosperm pollen grains Plicatipollenites spp. and Cannanoropollis spp. Also present are the lycopod spore Jayantisporites pseudozonatus, the praecolpate pollen grain Marsupipollenites striatus and the monocolpate pollen grain Cycadopites cymbatus. The palynoflora indicates freshwater conditions or, at least, a major freshwater influence on the depositional environment. Comparison of the palynoflora with others from Gondwana suggests an Early Permian (Asselian–Sakmarian) age.

Sub-Antarctic Marion Island was the site of extensive volcanism as well as glaciation during both the Quaternary and the Holocene. Initial reconstructions suggested a link between deglaciation and the initiation of faulting which, in turn, facilitated lava eruptions during the interglacials. However, our reassessment of the faulting, volcanic rock, and palaeoglacier distribution indicate that these original interpretations were erroneous. Features thought to be due to faulting are shown to be erosional scarps and this significantly changes interpretations of former glacier distribution. Further, the loss of the former ice cap has revealed new information on former glaciers and their flow directions, thereby allowing reconstruction of palaeoglaciers. Our new reconstruction fits with information from invertebrate genetic mapping that suggest some lava outcrops were nunataks and, therefore, refuges during the Last Glacial period. The new findings of glacial landforms in areas previously covered by snow suggest there was a significant ice advance during the Little Ice Age. Although Holocene volcanic rocks overlie and mask much of the glacial evidence, it has been possible to develop a proposed new reconstruction for glaciation, which is presented together with some of the implications.

A cytogenetic study on the bovichtid species Cottoperca gobio from the Magellan Strait and Pseudaphritis urvillii from Tasmania showed both species have a plesiomorphic number of chromosomes (2n=48). However, C.gobio has a more conservative karyotype composed entirely of acrocentric chromosomes (Fundamental Number=48); the presence of two metacentric pairs in P. urvilli (FN=52) makes this species karyologically more derived. The differences in the number of chromosomal arms, and the chromosomal location of the nucleolar organizer regions indicate karyological divergence in the two separating stocks from which C.gobio and P.urvillii originated. During the diversification of this notothenioid family, probably coincident with the fragmentation of Gondwana, the stock that split off with the Australian Plate gave rise to the Tasmanian species and experienced more chromosomal modifications than the stock from which C. gobio is derived. The pattern of constitutive heterochromatin suggests a possible homology between a pair of chromosomes in bovichtids and other notothenioids.

Comprehensive geochemical analyses (bulk parameters, major and trace elements, organic matter, mineralogy and particle analysis) were carried out on sediments from seven lakes on Fildes Peninsula, King George Island. The resulting compositional dataset was subjected to principal component analysis and cluster analysis. The results showed that four different lacustrine sedimentary environments can be distinguished: i) lakes 1 and 2 with relatively high values of secondary aluminous clay minerals, ii) lake 4 with anthropogenic enrichment of Co, Cu and Zn, iii) lake 7 with relatively high values of Ba and P and a high zeolite content, and iv) all the other studied lakes. Our results indicate moderate chemical weathering in all lacustrine sediments and that the distance to the glacial ice margin is one of the most important factors influencing the chemical weathering in the area. Furthermore, depositional processes have little influence on the geochemistry of the investigated elements and that local bedrock is the main source of sediments in the lakes on Fildes Peninsula.