In the last decade the notion of large subglacial lakes in Antarctica has attracted increasing attention. Lake Vostok is by far the largest of approximately 63 subglacial lakes now known in Antarctica, and the one about which most is known. The possible exploration of Lake Vostok was the subject of a very successful workshop held in Cambridge, UK, in September, 1999, sponsored by the Scientific Committee on Antarctic Research (SCAR) with the support of many others, and organized and hosted by the British Antarctic Survey.

Weaned pups and post-moult female elephant seals (Mirounga leonina) were fitted with satellite transmitters at King George Island (South Shetland Islands) between December 1996 and February 1997. Of the nine adult females tracked for more than two months, three stayed in a localized area between the South Shetland Islands and the South Orkney Islands. The other six females travelled south-west along the coast of the Antarctic Peninsula up to the Bellingshausen Sea. Two of them then moved north-east and hauled out on South Georgia in October. One female was last located north of the South Shetland Islands in March 1998. In total, eight females were again sighted on King George Island and six of the transmitters removed. The tracks of the weaners contrasted with those of the adults. In January, five juveniles left King George Island for the Pacific sector spending about four weeks in the open sea west of the De Gerlache Seamounts. Three of them returned to the tip of the Antarctic Peninsula in June, of which one was last located on the Patagonian Shelf in November 1997. The juveniles avoided sea ice while the adults did not. The latter displayed behavioural differences in using the pack ice habitat during winter. Some females adjusted their movement patterns to the pulsating sea ice fringe in distant foraging areas while others ranged in closed pack ice of up to 100%. The feeding grounds of adult female elephant seals are more closely associated with the pack ice zone than previously assumed. The significance of the midwater fish Pleuragramma antarcticum as a potential food resource is discussed.

In the summer of 1995/96, 25 southern elephant seals, Mirounga leonina, were stomach lavaged at Stranger Point, King George Island, South Shetland Islands. Cephalopod remains were present in 72% of the individuals sampled (n = 18). Seven species of squid and three of octopus were identified. The squid Psychroteuthis glacialis was the most important prey in terms of numbers (77%), biomass (80.8%) and frequency of occurrence (94.4%). Next in importance in terms of mass was the squid Alluroteuthis antarcticus (7.8%) in the diet of females and the octopodid Pareledone ?charcoti in the diet of males (13.2%). Females preyed on a wider variety of squid taxa than males (7 vs 3) but octopodids occurred only in stomach contents from males. The predominance of P. glacialis in the prey of the South Shetland Islands elephant seals can be explained by the southerly location of the foraging areas of this population compared to South Georgia, Heard and Macquarie islands, where the diet of southern elephant seals has previously been analysed. Psychroteuthis glacialis is the predominant squid in waters close to the Antarctic continent.

Primary productivity and associated biogeochemical fluxes within the Southern Ocean are globally significant, sensitive to change and poorly known compared to temperate marine ecosystems. We present seasonal time series data of chlorophyll a, primary productivity and in-water irradiance measured in the coastal waters of the Western Antarctica Peninsula and build upon existing models to provide a more optimum parameterization for the estimation of primary productivity in Antarctic coastal waters. These and other data provide strong evidence that bio-optical characteristics and phytoplankton productivity in Antarctic waters are different from temperate waters. For these waters we show that over 60% of the variability in primary production can be explained by the surface chlorophyll a concentration alone, a characteristic, which lends itself to remote sensing models. If chlorophyll a concentrations are accurately determined, then the largest source of error (13–18%) results from estimates of the photoadaptive variable (PBopt). Further, the overall magnitude of PBopt is low (median 1.09 mg C mg chl−1 h−1) for these data compared to other regions and generally fits that expected for a cold water system. However, the variability of PBopt over the course of a season (0.4 to 3 mg C mg chl−1 h−1) is not consistently correlated with other possible environmental parameters, such as chlorophyll, sea surface temperature, incident irradiance, day length, salinity, or taxonomic composition. Nonetheless, by tuning a standard depth-integrated primary productivity model to fit representative PBopt values and the relatively uniform chlorophyll-normalized production profile found in these waters, we can improve the model to account for approximately 72–73% variability in primary production both for our data as well as for independent historic Antarctic data.

A new octopod species, Graneledone gonzalezi sp. nov., is described from 19 specimens collected off the northern Îles Kerguelen. This is a bathyal octopus which is characterized by: the absence of supra-ocular papillae, short arms, a long ligula without copulatory ridges, a narrow head, six filaments per outer demibranch and radula exhibiting no archaic traits, medium size oocytes and a low number of very long spermatophores. Graneledone gonzalezi is compared with its other congeneric species and found most closely resemble G. antarctica. The geographic and bathymetric distribution of G. gonzalezi is also discussed.

Studies were continued to investigate the ability of secondary metabolites sequestered in Antarctic sponges to cause feeding deterrent responses (tube foot retractions) in a common predator of Aritarctic sponges, the sea star Perknaster fuscus. Lipophilic (dichloromethane/methanol) and hydrophilic (methanol/water) extracts of 15 new species of Antarctic marine sponges were tested for their ability to induce sustained tubefoot retraction. One additional species, Cinchyra antarctica, was re-tested from a previous study because we discovered a colour morph that was of comparative interest. Employing established protocols, sponge extracts were imbedded in silicone and presented to an extended tube-foot on the tip of a glass rod. Extracts of ten of the 15 new species of sponges (67%) caused significantly longer tube-foot retractions than controls. Among all sponges tested, significant tube-foot retraction activity was primarily associated with dichloromethane/methanol extracts (eleven sponge species or colour morphs), while significant tube-foot retraction activity was less common in response to methanol/water extracts (three sponges species or colour morphs). Both lipophilic and hydrophilic extracts from the sponges C. antarctica (yellow morph) and Scolymastia joubini elicited significant tube-foot retraction activity, suggesting that more than one compound from these speciesmight elicit tube-foot retractions in P. fuscus. Overall these findings lend considerable support to the hypothesis that there has been significant evolutionary selection for chemical defences among Antarctic marine sponges in McMurdo Sound, in contrast to earlier biogeographic selection models that predicted low levels of chemical defences in polar marine invertebrates.

Specimens of 22 species of pycnogonids belonging to twelve genera and seven families were collected during a cruise near Livingston Island, South Shetland Islands. Twenty two of the 94 stations yielded pycnogonids: the new species Ammothea hesperidensis is described fully, illustrated, and compared with similar species. The family Nymphonidae provided both the greatest diversity of species (seven) and number of specimens (35). The most abundant species were Achelia hoekii and Nymphon australe.

Pigment analysis (HPLC and fluorometry) and light microscopy observations of the gut content of Thelepus extensus (Terebellidae) and surrounding sediments were carried out at two hydrodynamically contrasting sites at subantarctic Îles Kerguelen; 1) a sheltered site (Port-Raymond) with a dense population of large-bodied animals, and 2) an exposed site (Port-aux-Français) with a scarce population of smaller individuals. Chlorophyll a derivatives (phaeophorbide a-like) were the most abundant pigments in sediments and polychaete digestive tracts. The second important group of pigments consisted of five unknown carotenoids of which two were present only in the polychaete digestive tract. Pigments in the muddy sediment at the sheltered site appeared to originate from the grazing activity of the polychaetes, as suggested by the high concentrations of degradation products and the same phaeophorbides observed both in the sediment and in the gut contents. Material originating from the dense Macrocystis pyrifera (Phaeophyceae) and Ulvae (Chlorophyceae) cover constituted a large part of the polychaetes' diet at this sheltered site, as indicated by macroalgal debris in the gut contents and the presence of violaxanthin in the sediment and lutein/zeaxanthin in both polychaetes and sediments. The polychaetes seem to adapt their grazing mode to the environmental conditions, preferring suspension feeding in the sheltered site and deposit feeding at the exposed site. The different morphologies, behaviours and life spans of the two conspecific populations may by linked to the contrasting hydrodynamics of the two sites and to their respective diets.

Little information is available regarding predator-prey interactions in High-Antarctic coastal systems. In this study, the predation of Trematomus bernacchii (Pisces: Nototheniidae) on Adamussium colbecki (Mollusca: Pectinidae) is described and the related impact on the population structure of the mollusc is hypothesized. Fishes and scallops were collected during several expeditions between 1990/91 and 1997/98 summers, in nearshore waters at Terra Nova Bay (Antarctica). Adamussium colbecki was the main food item of T. bernacchii and an ontogenetic prey-size selection was observed. The predation was mainly on medium size classes of the scallop. These were lacking in the A. colbecki population sampled in the same period suggesting that the impact of fish-feeding on the size structure of the natural population of the mollusc may be substantial. Two size classes of the Adamussium population were not preyed on. Large adults avoid predation either because of the limits for mouth gape in the fish or by swimming avoidance capability, while smaller scallops may not be preyed upon because they are attached through byssus threads to very mobile large adults.

Surface patterns of alternating snow and blue-ice bands are found in the Jutulgryta area of Dronning Maud Land, Antarctica. The snow-accumulation regions exist in the lee of blue-ice topographic ridges aligned perpendicular to winter winds. The snow bands are c. 500–2000 m wide and up to several kilometres long. In Jutulgryta, these features cover c. 5000 km2. These alternating snow and blue-ice bands are simulated using a snow transport and redistribution model, SnowTran-3D, that is driven with a winter cycle of observed daily screen-height air temperature, humidity, and wind speed and direction. The snow-transport model is coupled to a wind model that simulates wind flow over the relatively complex topography. Model results indicate that winter winds interact with the ice topographic features to produce alternating surface patterns of snow accumulation and erosion. In addition, model sensitivity simulations suggest that subtle topographic variations, on the order of 5m elevation change over a horizontal distance of 1 to 1.5 km, can lead to snow-accumulation variations that differ by a factor of six. This result is expected to have important consequences regarding the choice of sites for ice-coring efforts in Antarctica and elsewhere.

Sediment cores from Abel and Platcha Bays, in the Vestfold Hills, east Antarctica, contain evidence for a local late Holocene increase in fast ice extent and a possible ice cap retreat at approximately 1750 yr BP, a similar time to the Chelnock Glaciation. Prior to this time both bays experienced periods of isolation that lead to changes in their diatom flora, C:N ratio, percentage of biogenic silica and total organic carbon. Three new diatom indices are proposed; the fast ice index, based on the proportion of fast ice taxa present, the benthic index, based on the proportion of benthic taxa and the snow index, based on the proportion Berkelaya adeliense and Thalassiosira ausiralis. These indices show strong relationships with the percentage of biogenic silica, total organic carbon and percentage sand. A weak relationship exists between the fast ice index and ∂13C and no relationship with the C:N ratio.

In North Victoria Land (Antarctica), the Wilson Terrane is a portion of the palaeomargin of the East Antarctic Craton, deformed during the Late Cambrian–Early Ordovician Ross Orogeny. Crustal deformation, from westward subduction of the palaeo Pacific plate and terrane accretion on this palaeomargin, gave rise to the development of a transpressive fold belt and a wide magmatic arc. In the inner portion of the Wilson Terrane, (Deep Freeze Range–Eisenhower Range) a large portion of this magmatic arc is made up of intrusions and dyke systems. Intrusive rocks range from large unfoliated plutons to well foliated sheet intrusions emplaced in low and medium–high grade metamorphic rocks respectively. Field and structural data on intrusive rocks and metamorphic host rocks, coupled with parameters relative to deformation mechanism and magmatic processes (crystallization and cooling) rates, make it possible to outline an episode of diffuse synkinematic magmatism in the Wilson Terrane. The emplacement of intrusions in both the middle and upper crust was coeval and related to the development of transpressional and transtensional structures along dextral strike-slip shear zones. Furthermore the development of foliated or unfoliated fabrics is related to competition between rates of deformation and magmatic processes, which is a function of the thermal state of the host rocks.

Experiments to reconstruct the liquidus curve and establish the phase relationships of a basanite (Mg# = 72) from the McMurdo Volcanic Group, (thought to represent a nearly primary magma) used 1.0– 3.0 GPa and 1175–1550°C. The results suggest that this basanite could be generated by partial melting either of a spinel Iherzolite (at P = 1.5–2.0 GPa and T = 1390–1490°C) or of a garnet pyroxenite (at P > 3.0 GPa and T > 1550°C) source. Several lines of petrological and geochemical evidence support the latter hypothesis. Moreover, experimental results indicate the presence of mica in the source if it is assumed that the magma lost some water during its ascent to the surface. This is supported by the presence of mica and amphibole-bearing mantle xenoliths hosted in the most primitive volcanic rocks of the McMurdo Volcanic Group. These results and observations suggest that the source of magmas underwent metasomatism prior to partial melting.

Vertical displacements of emerged land caused by oceanic tidal loading are of the order of several tens of millimetres in polar regions. They constitute a long wavelength signal, the amplitude of which is comparable to elevation changes that might be associated with climate-driven changes in ice-sheet volume. Using bilinear interpolation on a 1° by 1° global grid, we examine the amplitudes and phases of vertical displacements caused at any given epoch by the eight most important ocean tide constituents of recent ocean tide models, extrapolated to high latitudes. This permits estimation of the oceanic tidal loading corrections to measurements made by a satellite altimeter along the satellite ground track. We have done so systematically over Antarctica, for a scenario flight of ICESAT, which carries the Geoscience Laser Altimeter System (GLAS), whose primary science goal is to monitor ice-sheet mass balance. Ocean loading tide corrections near the coast of Antarctica can reach several centimetres; overall they average about 10 min.