Details are presented of seismic velocities at a site near Rothera Point, Adelaide Island, Antarctic Peninsula. The snow/firn velocity structure was obtained using a 24-channel Bison 9000 seismograph, recording the outputs of geophones of 40 Hz natural frequency attached to 150 mm snow spikes. The refraction velocity of the underlying bedrock was measured using a 48-channel DFS V recorder and 10 Hz geophones. The records were obtained during trials of equipment and techniques which took place in the 1988–89 and 1990–91 seasons. The data will be of interest to other investigators studying firn structure around Antarctica or considering crustal seismology in the Antarctic Peninsula region.

The distribution of annual mean biomass of mesozooplankton (animals in the size range 0.2–20 mm) in the upper layer (0–100 m) of the Atlantic sector of the Southern Ocean was mapped. The map was constructed from 4216 measurements at 2184 oceanographic stations, from the Russian and Brazilian archive records, from published sources, and from the British Oceanographic Data Centre. The annual mean mesozooplankton biomass value for the South Atlantic is estimated in this study to be 93 mg m−3 wet weight.

One-year time-lapse images acquired via an autonomous photo imaging device positioned at a depth of 20 m in Tethys Bay (Ross Sea, Antarctica) on a rocky bottom colonized by the sponge Mycale (Oxymycale) acerata were analysed. Monthly changes in the abundance and activity of the sea star Odontaster validus and sea urchin Sterechinus neumayeri on the sponge and nearby rocky bottom were compared with respect to environmental variables such as pack-ice presence/absence, temperature, salinity and photosynthetically active radiation. Sea urchins were more abundant on the rocky bottom and sponge during the summer and winter, respectively. Sea stars showed a decrease in the number of individuals on the sponge from January to December. The grazing activity of both species reached its maximum in January–April, when increased sunlight contributed to the phytoplankton bloom. The winter months were critical both for O. validus and S. neumayeri; although the red sea star maintained its pattern of activity on the rocky bottoms in terms of searching for food, the sea urchin reduced its activity. Time-lapse monitoring systems coupled with physicochemical sensors showed potential for revealing species behaviour in polar environments, contributing to the elucidation of future changes in coastal communities facing climate change.

The Wilkes Land Gravity Anomaly, first reported in 1959–60, is located in northern Victoria Land in the Pacific Ocean sector of East Antarctica, 1400 km west of the Ross Sea and centred at 70°00'S-140°00'E. Initially described on the basis of ground-based seismic and gravity survey, and estimated at the time to have a diameter of 243 km, the original data are now supplemented by data from airborne radiosound survey, airborne gravity survey, airborne magnetic survey and satellite remote sensing. These new data enable us to expand upon the original data, and reveal that the structure has a diameter of some 510 km, is accompanied by ice streams and a chaotically disturbed region of the continental ice sheet, has a subglacial topographical relief of ≥1500 m, and exhibits a negative free air gravity anomaly associated with a larger central positive free air gravity anomaly. The feature has been described as a volcanic structure, an igneous intrusion, an ancient igneous diapir, a subglacial sedimentary basin, a glacially eroded subglacial valley, a tectonic feature and a meteorite impact crater. We re-examine the feature on the basis of these collective data, with emphasis on the free air gravity anomaly signs, magnitudes and patterns, magnetic signature magnitudes and patterns, and the size, shape, dimensions and morphology of the structure. This enhanced view adds substantially to the original description provided at the time of discovery, and suggests several explanations for the origin of the Wilkes Land Anomaly. However, the importance of this feature lies not only in determining its origin but by the fact that this part of the Wilkes Subglacial Basin is one of the most prominent regional negative geoid and associated gravity anomalies of the Antarctic continent.

Nuculid bivalves of the Cape Melville Formation (Early Miocene, King George Island) are reviewed. Ten bivalve taxa are listed from the formation in the families Nuculidae (two species), Sareptidae, Malletiidae, Limopsidae (two species), Limidae, Pectinidae, Hiatellidae, and Periplomatidae. The Nuculidae consist of two species of Leionucula Quenstedt, 1930. One of these, L. melvilleana n. sp., is described and the other consists of the two species named previously by Anelli et al. (2006), which are demonstrated to be synonymous and are assigned to the species Leionucula frigida (Anelli, Rocha-Campos, Santos, Perinotto & Quaglio 2006). This assemblage, dominated by protobranchs (89% of specimens), is a typical fauna of offshore soft substrates, with a few specimens transported from hard substrates nearby. The diversity of Nuculidae has decreased in the Antarctic region through the Cenozoic.

There is a potential threat to marine mammals from acoustic signals emitted by hydroacoustic devices. The impact on the hearing of marine mammals depends on the technical parameters of the instruments and on the exposure of the animal to noise pulses, as well as on the properties of the biological system, that is to say, on the anatomy and the audiogram of the animal. Here, the blue whale, the sperm whale and the beaked whale are taken as examples in an investigation of the potential exposure to noise pulses from the hydroacoustic instruments Hydrosweep and Parasound. Diving depths of the whales and relative speeds of the animals with respect to the survey vessels are taken into account, as well as the area impacted by the equipment, in estimating the level of sound needed to produce “temporary threshold shift” in an animal. The results suggest that auditory damage is only likely if animals pass the transducer at close range and that the impact on marine mammals can be mitigated by implementing prior detection and shut down procedures.

Nowadays it is well accepted that background aerosols in the boundary layer over remote oceans are of marine origin and not aged continental. Particularly in the Atlantic sector of the Southern Ocean at least four main important regions exhibit significant ocean primary productivity. They are the Bellingshausen–Amundsen Sea, the Weddell Sea, the southern Argentinean shelf and the southern Chilean coast. In this work, we have combined ground-based continuous atmospheric sampling of aerosol number concentration (ANC), over-sea dimethyl sulphide (DMS) measurements, chlorophyll a (chl a) concentration provided by Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite images, in situ meteorological data and monthly regional NCEP-NCAR re-analysis wind fields in order to investigate the relative contribution of each of the above regions to the apportionment of the ANC at King George Island (KGI), South Shetland Islands. Our results suggest that, at least during the period from September 1998–December 1999, the southern Argentinean shelf acted as the main contributor to the ANC measured in KGI.

This study looks at the feasibility of using Ocean Acoustic Tomography for long-term monitoring of polynyas using both observations in Terra Nova Bay polynya (Ross Sea) and simulations with a range dependent, multi-layered adiabatic normal mode acoustic propagation model. The summer sound speed profile is characterized by surface values of around 1450 m s−1, a minimum of 1441 m s−1 around 50 m depth and a linear increase with a 0.016 s−1 slope. Thus, the sound propagation is apparently ducted in the near surface layer and is refracted upward below it. During winter, due to water cooling and mixing processes, the subsurface minimum disappears, the surface sound speed is about 1440 m s−1 and no near surface layer ducted propagation occurs. Because of the specificity of the Terra Nova Bay seasonal sound speed profile and to cope with both deep and shelf water applicability, the feasibility study of acoustic inversion was undertaken using normal mode Match Field Tomography instead of the more classical travel-time inversion. The results from simulations demonstrate that ocean acoustic tomography is able to reproduce quite well the vertical sound speed profile, in particular the temporal evolution of summer stratification and winter mixing processes, thus providing information on the upper layer, where direct measurements are not possible.

We report here the discovery of a boulder pavement cropping out at the base of the Hobbs Glacier Formation (Miocene), on the northern sector of Seymour Island (Isla Marambio), West Antarctica, along the contact with the underlying La Meseta Formation (Eocene). The feature described has many points in common with boulder pavements developed in tidal-marine environments. The clasts of the pavement are mostly boulders and bear up to three sets of glacial striae on their bevelled truncated surfaces, but are not elongate parallel to them or bullet shaped. No diamictite body was identified associated with the boulder pavement. These features differ from those of boulder pavements described from terrestrially glaciated Cenozoic deposits and may indicate a shallow glaciomarine environment for the late Cenozoic of Seymour Island.

The structural basement of Alexander Island consists of a wide belt of accretionary complex rocks, the LeMay Group (Bum 1984). This is overlain by ?Cretaceous-Tertiary calcalkalinevolcanic rocks (Bum 1981), and intruded by several slightly younger, but related, plutons (Care 1983). The Rouen Mountains batholith is a large group of these plutons which occurs in the northern part of the island.

Unmanned magnetometer stations (UMS) have been developed and were installed at remote location near Syowa station, Antarctica (69°S, 40°E) to perform field tests in the harsh Antarctic environment. The UMS was powered by a thermo-electric generator fuelled by kerosene (LTEG) which supplies 87 Watts continuously to the load. The LTEG and instrumentation (flux gate magnetometer, data logger, chronometer) were installed in a thermally insulated shelter (0.9 m by 1.8 m by 1.9 m). The shelter and an 800 l fuel tank were mounted on a sled, and were towed by snow tractor. The UMS were installed at Kizahasi beach, Skarvsnes (50 km south-west of Syowa) and at H-100 of the Mizuho route (100 km south of Syowa) in the early spring of 1988 and operated until the end of the year. The data obtained will be used for a study of the spatial phase and amplitude structure of the ionospheric current systems and a response of the local induction currents to them.