The role of fish in the Antarctic food web in inshore and offshore waters is analysed, taking as an example the coastal marine communities of the southern Scotia Arc (South Orkney Islands and South Shetland Islands) and the west Antarctic Peninsula. Inshore, the ecological role of demersal fish is more important than that of krill. There, demersal fish are major consumers of benthos and also feed on zooplankton (mainly krill in summer). They are links between lower and upper levels of the food web and are common prey of other fish, birds and seals. Offshore, demersal fish depend less on benthos and feed more on zooplankton (mainly krill) and nekton, and are less accessible as prey of birds and seals. There, pelagic fish (especially lantern fish) are more abundant than inshore and play an important role in the energy flow from macrozooplankton to higher trophic levels (seabirds and seals). Through the higher fish predators, energy is transferred to land in the form of fish remains, pellets (birds), regurgitation and faeces (birds and seals). However, in the general context of the Antarctic marine ecosystem, krill (Euphausia superba) plays the central role in the food web because it is the main food source in terms of biomass for most of the high level predators from demersal fish up to whales. This has no obvious equivalent in other marine ecosystems. In Antarctic offshore coastal and oceanic waters the greatest proportion of energy from the ecosystem is transferred to land directly through krill consumers, such as flying birds, penguins, and seals. Beside krill, the populations of fish in the Antarctic Ocean are the second most important element for higher predators, in particular the energy-rich pelagic Myctophidae in open waters and the pelagic Antarctic silver fish (Pleuragramma antarcticum) in the high Antarctic zone. Although the occurrence of these pelagic fish inshore has been poorly documented, their abundance in neritic waters could be higher than previously believed.

The goal of this study was to demonstrate the role of isolation on the social behaviour of individuals and to characterize its adaptation as a function of time. The ethological method used was a quantitative description of the spatial positioning of a sub-group of 13 wintering members during the morning, midday and evening meals at Dumont d'Urville station. The observation protocol required the completion of first daily and then weekly (every Thursday) observation maps at different stages of the 13 month long polar mission, from the information seminar in France, the trips outward and return aboard the Astrolabe, the two summer campaigns at the beginning and at the end of the mission and the overwintering period. Results, mainly expressed as human concentration and spatial dispersion indexes, have successively shown organization, disorganization and reorganization periods of the small group without any significant cycling. Socialisation rules promoting the group building in the early period, conflict factors and relay steps (external perturbations breaking the isolation, transitions during group displacement from one stage to another) promoting the maintenance of the social cohesion, are outlined in the discussion.

Hydrocarbon spills have occurred on Antarctic soils where fuel oils are utilized, moved or stored. We investigated the effects of hydrocarbon spills on soil temperature and moisture regimes by comparing the properties of existing oil contaminated sites with those of nearby, uncontaminated, control sites at Scott Base, the old Marble Point camp, and Bull Pass in the Wright Valley. Hydrocarbon levels were elevated in fuel-contaminated samples. Climate stations were installed at all three locations in both contaminated and control sites. In summer at Scott Base and Marble Point the mean weekly maximum near surface (2 cm and 5 cm depth) soil temperatures were warmer (P<0.05), sometimes by more than 10°C, at the contaminated site than the control sites. At Bull Pass there were no statistically significant differences in near-surface soil temperatures between contaminated and control soils. At the Scott Base and Marble Point sites soil albedo was lower, and hydrophobicity was higher, in the contaminated soils than the controls. The higher temperatures at the Scott Base and Marble Point hydrocarbon contaminated sites are attributed to the decreased surface albedo due to soil surface darkening by hydrocarbons. There were no noteworthy differences in moisture retention between contaminated and control sites.

Non-krill prey remains were recovered from ornithogenic sediments at three active Adélie penguin colonies on Ross Island, to assess long-term dietary trends in this species. Radiocarbon dates place the age of these deposits from a maximum of 947 years ago to the present. We identified 12 taxa of fish and two of squid with the Antarctic silverfish (Pleuragramma antarcticum) as the most abundant prey species represented at all sites. In addition, silverfish have decreased in importance in Adélie penguin diet over the past 600 years, perhaps in response to climate change since the onset of the Little Ice Age, though it remains much more abundant in current penguin diet in the Ross Sea than in the Antarctic Peninsula. Other prey taxa reflect the diversity of prey selection by Adélie penguins in Antarctica.

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.

This study aimed to use nutrients in lake inflows as proxies for assessing human impact and separating this from natural transformations of material in the soil active layer. Nutrients, conductivity and δ18O were monitored in surface and subsurface (using ceramic tipped piezometers) lake inflows during summer in near natural and human impacted catchments. The nutrient levels were highly variable but generally higher during the last weeks of the flow, in both subsurface waters and in human impacted catchments. Up to 2000 μgN l−1 subsurface dissolved inorganic nitrogen (DIN) was measured in human impacted catchments but only 315 μg N l−1 in natural catchments. Subsurface levels of dissolved reactive phosphorus (DRP) were up to 310 μgP l−1 in natural catchments and up to 108 μgP l-1 in human impacted catchments. The maximum levels of both DIN and DRP in surface inflows were much higher in human impacted than in natural catchments. Conductivity and δ18O data showed general enrichment of snowbank meltwater presumably through evaporation from the active layer. This combined with fluctuating nutrient levels in catchment waters indicated that soil brines and decaying organic matter of natural and human origin were possible sources for nutrients and other salts. Marked salinization and substantially increased DIN levels near the research stations indicated that lake waters were receiving nutrients generated by humans.

The study of polychaetes from the Marion Dufresne expedition to the Îles Crozet in 1982 provided 45 species from depths ranging from 50–1055 m. The most abundant was Eunice pennata, found at all depths and in all types of substratum in about 66% of the samples. This species with Laetmonice producta, Harmothoe spinosa and Lanice marionensis made up over 50% of all polychaete specimens. A homogenous polychaete assemblage dominated by the above mentioned group of species was encountered in the shallower stations (100–300 m). A mosaic-like and less abundant polychaete fauna with some characteristic, abundant species: Amage sculpta, Laetmonice wyvillei, Leanira quatrefagesi and Melinna cristata was encountered in the deeper stations (300–1055 m). Clear similarities between the polychaete fauna of Îles Crozet and soft-sediment polychaete assemblages of Marion and Prince Edward Islands were noticed. No such affinity was encountered with the polychaete fauna of Îles Kerguelen. Their position in relation to the Polar Front as well as possible differences in bottom deposits (calcareous versus siliceous) may in part explain these dissimilarities. The biogeographical status of Kerguelen Islands is also discussed.

Two mitochondrial DNA regions and seven microsatellite loci were examined in Patagonian toothfish from three locations in the Southern Ocean (Macquarie Island, five collections; Heard and McDonald Islands, four collections; Shag Rocks/South Georgia area, one collection). Striking mtDNA heterogeneity was detected between the three fishing locations (FST=0.445, P<0.001), but spatial and temporal collections within the same location were not significantly different. No significant overall microsatellite differentiation between the three locations was apparent (FST=−0.009, P=0.785). However, some individual loci showed small but significant differentiation, which in each case was attributable to between rather than within-location differentiation. Greater differentiation of mtDNA can, in principle, be explained either by female philopatry and male dispersal, or by its greater sensitivity to changes in effective population size. The latter seems more likely as tagging indicates that toothfish is generally a sedentary species. The genetic heterogeneity between the three locations indicates restricted gene flow, with the fish at each location comprising independent units. Depletion in one location is therefore unlikely to be quickly replaced by immigration from another.

The shore environments of most sub-Antarctic islands have been described in a number of previous studies. However, there have been few attempts to quantify the variation in population and community patterns over different spatial scales. The objectives of this study were to provide an analysis of differences in the community structure of the biota of three exposed shore zones and of the macrofauna inhabiting holdfasts of the kelp Durvillaea antarctica across spatial scales of hundreds of metres, kilometres, and between a sheltered and exposed coast. Data were collected using a combination of quadrat, transect and direct sampling methods over the 1994–95 summer season. The results indicated that there were significant differences between coasts for some of the biotic variables in most of the habitats examined but that differences at the smaller spatial scales were more often significant. Thus, although wave exposure exerts an obvious effect on the shore biota of Macquarie Island, these effects are modified by other factors operating at smaller spatial scales. For the holdfast macrofauna, the overall patterns of community structure are likely to be due to the differential response of the component taxa to variation in holdfast volume and holdfast sediment content as well as other, currently undetermined factors.

Analyses on a sediment core collected from the Windmill Islands, East Antarctica are used to demonstrate that climatic conditions in this region prior to the Last Glacial Maximum were similar to those during the Holocene and that the area was overrun by ice at some stage between 26 kyr BP and the onset of biogenic sedimentation 11 kyr BP. The 10.9 m long core was taken from a marine inlet (epishelf lake) on Peterson Island and is predominantly a sapropel of Holocene age. Material in the lower part of the core includes a till layer lain down during the last glacial in the region and below this till is material which has been dated to 26 kyr BP. Geochemical analyses conducted on the core demonstrate similarities between the Holocene sequence and the preglacial material. The Holocene sequence shows enhanced biogenic production and periods of open water around 4 kyr BP, suggesting a climatic optimum around that time. A subsequent decline in conditions, probably a colder climate with greater extent of sea ice, is evident from 1 kyr BP to the present. The data support results from ice core studies on nearby Law Dome, which suggest there was a period of warming around 11.5 to 9 kyr BP, that recent summer temperatures are low relative to a few centuries ago, and that increasing winter temperatures are the main contributing factor to a recent overall warming in the region.

Six ichnocoenoses in the clastic Devonian Horlick Formation (max. 56 m) confirm the nearshore marine character of eight of the nine lithofacies present. Abasal sand sheet overlies a weathered granitic land surface (Kukri Erosion Surface) on Cambro–Ordovician granitoids. The level nature of this surface and the way it cuts across weathering profiles, suggests that the surface had been modified by marine processes prior to deposition. The basal sand sheet (Cross-bedded Sand sheet Lithofacies) contains tidal bundles, and at its top, abundant Monocraterion (Monocraterion Ichnocoenosis). The second sand sheet (Pleurothyrella Lithofacies) is heavily burrowed and shows alternating periods of sedimentation, burrowing, and erosion below wave base as the sea deepened (Catenarichnus Ichnocoenosis). With increasing transgression, finer sediments were deposited (Laminated Mudstone and Feldspathic lithofacies) in an unstable pattern of coarse sandbars and finer troughs (Cruziana-Rusophycus and Arenicolites ichnocoenoses) crossed by active longshore marine channels (Poorly-sorted Lithofacies, Spirophyton Ichnoocoenosis). Short-lived but powerful storms produced thin shelly tempestites (Shell-bed Lithofacies), whereas sporadic, very thin phosphate rich beds (Phosphatic Lithofacies) may have resulted from marine transgressions across the basin. The deepest water is probably represented by sediments of the Spirifer Lithofacies (Rosselia Ichnocoenosis). The Schulthess Lithofacies is regarded as fluvial, deposited in the lower reaches of a river draining a land area that lay towards Marie Byrd Land. Channels in the basal sand sheet indicate movement to the southwest, but orientation became more variable higher in the sequence. Four new measured sections are figured. The relationship of the Ohio Range to the rest of Antarctica during the Devonian is suggested.

Bransfield Strait, a narrow active rift with three submarine basins, separates the South Shetland Islands from northern Antarctic Peninsula. Volcanism in Bransfield Strait commenced prior to 0.75 Ma and continues, with recent subaerial eruptions at Deception, Bridgeman and Penguin islands, submarine hydrothermal activity and numerous young basaltic seamounts located along the rift axis. Gravity cores were collected from five locations within the central Bransfield basin. Diatomaceous mud interbedded with terrigenous detritus and discrete ash layers up to 10 cm thick are the commonest sediment types in all the cores. The major element compositions of glass shards within the ash layers are, apart from the uppermost layer, compositionally similar to pyroclastic units preserved on Deception Island, a young (<0.75 Ma) active stratovolcano. The uppermost ash layer cannot be closely matched compositionally to any known source in the Antarctic–Scotia Sea–southern South America region. Its presence indicates that a volcanic centre other than Deception Island contributed ash to the Bransfield basin. Based on the shallow stratigraphical position of the compositionally distinctive ash layer, only a few decimetres beneath the seafloor, its source volcano was probably active in historical times (<few hundred years).

The Horlick Formation is a fossiliferous, predominantly marine succession of interbedded sandstone and mudstone that crops out along a prominent escarpment in the Ohio Range. The formation buries a relatively level wave-cut platform eroded across a basement granitoid, and is nowhere more than 56 m thick due to subsequent Permo–Carboniferous glacial erosion.

The sediments have been described in terms of nine lithofacies (Bradshaw & McCartan 1983, McCartan & Bradshaw 1987), that were renamed in conjunction with the establishment of six ichnocoenoses (Bradshaw et al. 2002). An abundant but relatively limited shelly fauna was described by Doumani et al. 1965 and Bradshaw & McCartan 1991.

The six ichnocoenoses within the Horlick Formation have been used in palaeoenvironmental interpretations (Bradshaw et al. 2002). Catenarichnus is an important element and name bearer for one of these ichnocoenoses. Detailed descriptions of the remaining ichnofauna will be described in a separate paper.

The Darwin Glacier region is located between the Carlyon and Darwin glaciers in southern Victoria Land, Antarctica (Fig. 1). Previous work on Ross Orogeny granitoids of the Darwin Glacier region is mutually conflicting. Haskell et al. (1965) mapped three plutons, the Carlyon Granodiorite, Mount Rich Granite and Hope Granite, Felder & Faure (1990) did not recognise the Hope Granite, and Encarnación & Grunow (1996) interpreted the entire area as underlain by a single intrusion, the Brown Hills pluton. Fieldwork during the 2000 field season and subsequent geochemical and geochronological analysis described here indicates the presence of three distinctive granitic suites, emplaced during Cambrian times. These include the Foggy Dog Granite (FDG) suite, the Darwin calcic suite and the Cooper Granodiorite.