Miocene–Recent alkaline volcanic rocks form numerous outcrops scattered widely throughout the Antarctic Peninsula and eastern Ellsworth Land. They occur mainly as short-lived (typically 1–2 million years) monogenetic volcanic fields but include a large outcrop area in northern Antarctic Peninsula which includes several substantial polygenetic shield volcanoes that were erupted over a 10 million year period (the James Ross Island Volcanic Group (JRIVG)). As a whole, the outcrops are of considerable importance for our understanding of the kinematic, petrological and palaeoenvironmental evolution of the region during the late Cenozoic. Until now, there has been no formal stratigraphical framework for the volcanism. Knowledge of the polygenetic JRIVG is still relatively poor, whereas a unifying lithostratigraphy is now possible for the monogenetic volcanic fields. For the latter, two new volcanic groups and twelve formations are defined, together with descriptions of the type sections. The volcanic fields (both polygenetic and monogenetic) vary in area from c. 1 to 4500 km2, and aeromagnetic data suggest that one may exceed 7 000 km2. The rocks are divisible into two contrasting petrological ‘series’, comprising basanites–phonotephrites and alkali basalts–tholeiites. The JRIVG is dominated by alkali basalts–tholeiites but also contains rare basanites, and phonotephrite–tephriphonolite compositions occur in minor pegmatitic segregations in sills. By contrast, in the monogenetic volcanic fields, basanites–phonotephrites generally form the older outcrops (mainly 15–5.4 Ma) and alkali basalts–tholeiites the younger outcrops (4(?)–<1 Ma). Throughout the region, erupted volumes of alkali basalts–tholeiites were an order of magnitude greater, at least, than those of basanite–phonotephrite compositions. Interpretation of the lithofacies indicates varied Miocene–Recent palaeoenvironments, including eruption and deposition in a marine setting, and beneath Alpine valley glaciers and ice sheets. Former ice sheets several hundred metres thick, and fluctuating ice surface elevations, which were generally higher during the eruptive periods than at present, can also be demonstrated.

For the Filchner–Ronne Ice Shelf we have compiled measurements of meteoric ice thickness from many institutions, and several different techniques (e.g. radar and seismic sounding) to produce an improved digital map of meteoric ice thickness. This map has high-resolution compared to previous compilations and serves to highlight small-scale geographic features (e.g. ice plains, grounding-line regions). We have also produced a map of the thickness of marine ice bodies beneath the ice shelf by using borehole density data to calibrate an ice thickness to surface-elevation relation, and then comparing maps of ice surface elevation and meteoric ice thickness to infer marine ice thickness. Due to denser data coverage and the improved density-depth relation, the resulting map is a significant improvement on its predecessors and allows insight into the glaciological context of the ice shelf, in particular, into the location of the grounding lines on the southern Ronne Ice Shelf. Here the data were supplemented with barometric determination of surface elevation, which were used to locate the grounding line position. The final delineation of the grounding line position was confirmed by reference to satellite imagery, and revealed that earlier estimates were substantially in error, especially in the area of Foundation Ice Stream and Möllereisstrom.

In an attempt to improve the understanding of the natural variability and distribution of trace elements in Antarctic organisms, the concentrations of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, vanadium and zinc in representative benthic species from two pristine coastal environments were measured and compared with literature data for other uncontaminated coastal ecosystems. Correlations between the elements, differences between the species and between the sampling sites were examined by principal component analysis. Metal accumulation was particularly evident in the tissues of the sea star Odontaster validus, the bivalve mollusc Laternula elliptica and in the red alga Phyllophora antarctica. However, metal accumulation was not the same for all the analytes, but, rather, depended on the organism characteristics. In particular, the soft tissues of Odontaster validus were characterized by high concentrations of cadmium, zinc and copper, those of Phyllophora antarctica by high concentrations of manganese and nickel, and the tissues of Laternula elliptica by high concentrations of all measured elements, particularly in its digestive gland. The Antarctic data as well as those reported for other pristine coastal ecosystems showed remarkably high natural variability in metal content, which must be taken into account when interpreting results from biomonitoring programmes.

This paper is a contribution to the Latitudinal Gradient Project. It describes macro and epifaunal assemblages and habitats at three shallow water locations at the southern end of the western Ross Sea coast, and investigates relationships between faunal composition and environmental characteristics. Many variables (e.g. substrate type, sediment composition, depth, latitude, longitude) contributed to explaining the differences in community composition between locations, with latitude (a likely surrogate for broader scale factors, e.g. ice cover) one of the most important. The percentage explained by environmental characteristics was strongly scale dependent, decreasing with increasing scale of observation. As much as 66% and 75% of the variability in macrofaunal and epifaunal assemblages, respectively, was explained at the smallest scale (i.e. between transects within a location), compared to 9–18% and 11–32%, respectively, at the scale of the entire study. This relationship was also true for species richness and total abundance. This suggests that while small-scale habitat variability will not confound our ability to detect latitudinal gradients in future studies, adequately quantifying the environmental factors important in structuring these communities at larger (latitudinal) spatial scales will be important. Finally, large differences in habitat structure did not translate into large differences in the diversity of fauna, illustrating the difficulty of predicting faunal composition in the Ross Sea based on seafloor topography alone.

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.

Nearshore marine benthic algal communities along the western Antarctic Peninsula harbour extremely high densities of amphipods that probably play important roles in nutrient and energy flow. This study extends our evaluation of the importance of amphipods in the nearshore Antarctic Peninsular benthic communities and focuses on sponge associations. We found a mean density of 542 amphipods per litre (L) sponge for twelve species of ecologically dominant sponges. The highest mean density (1295 amphipods per L sponge) occurred with Dendrilla membranosa Pallas. The amphipod community associated with the 12 sponges was diverse (38 species), with mean species richness values ranging from two to eight species. Mean Shannon diversity indices (H’) ranged from 0.52 to 1.49. Amphipods did not appear to have obligate host relationships. Qualitative gut content analyses indicated that 12 of the 38 amphipod species were found with sponge spicules in their guts. However, only one of the amphipods, Echiniphimedia hodgsoni Walker, had considerable amounts of spicules in the gut. Organic lipophilic and hydrophilic extracts of the twelve sponges were presented in alginate food disks to a sympatric omnivorous amphipod in feeding bioassays and extracts of only two sponges deterred feeding.

The Antarctic continent and the peripheral ocean regions are the primary source of information on the Cenozoic cryosphere and events leading up to its development at least 36 million years ago. From a variety of data it is now apparent that the southern high latitudes have been subjected to a dynamic alternation of ice sheet expansion and decay through the late Palaeogene and Neogene. This history of climate change was accompanied by, and certainly strongly influenced by, significant vertical and horizontal lithosphere changes, including the evolution of major internal seaways and mountain ranges. The imprint of this record is preserved in the marine successions of the polar basins, in the world's bathyal and abyssal ocean basins and in the continental shelves of other continents, including those of the Northern Hemisphere. The Antarctic and extra-Antarctic terrestrial and marine data bases have developed separately in the past three decades and geospheric and biospheric information must now be integrated across latitudes. Future success in deciphering climate change depends on a better understanding of glacial–deglacial cycles from the point of view of both direct Antarctic and indirect or proxy extra-Antarctic data, through the complete temporal range of 107 to 103 years. Unfortunately, much of the high latitude record for the past 65 million years of earth history is presently veiled by thick ice sheets/ice shelves and deep and often ice-covered marine waters. Without the intensive application of the most advanced remote sampling equipment on the continent and in the Southern Ocean it will be difficult for this region to contribute significantly to global change and global climate programmes.

Photosynthetic photon flux density (PPFD), air relative humidity and thallus temperature (TT) were measured in Usnea antarctica over a period of 12 months at a coastal rock on King George Island, South Shetland Islands. TT had an annual amplitude of c. 54 K with the maximum of +27.4°C recorded in December and minimum of −27.3°C in July. Daily maximum TT exceeded 0°C every month except in June and July when they were below −0.4°C and −1.6°C, respectively. Daily minimum temperatures were always below zero. Diel courses of PPFD showed pronounced seasonal differences between summer (more than 2000 μmol m−2s−1) and winter (less than 50 μmol m−2s−1 in July). Daily sum of PPFD was highest (more than 30 mol m−2d−1) in December and lowest (0.1 mol m−2d−1) in July. A photosynthesis model was used to estimate the potential annual primary production from habitat PPFD and TT. The estimated potential annual carbon balance of U. antarctica was 323 mg CO2 g−1 dry weight y−1 assuming that the lichen was always at optimal moisture. The potential carbon balance indicates that primary production is severely limited by low PPFD and subzero TT in the austral winter. Nevertheless, the PPFD and TT would allow metabolic activity during winter but with a negative carbon balance during May–August. Spring and autumnal months are revealed as probably the most important periods for lichen primary production because PPFD exceeds photosynthetic light compensation point during the daytime and ambient moisture conditions frequently favour a positive carbon balance.

Recent rapid retreat of glacial front lines and the loss of land ice along the Antarctic margins may play an important role in exporting suspended particulate matter (SPM) potentially rich in bioavailable (defined as ascorbate leachable) iron (FeA) to coastal areas of the Southern Ocean. Sediment ablation is an additional source of iron for this high-nutrient low-chlorophyll region. In Potter Cove, King George Island, meltwater streams discharge up to 18 000 mg l-1 (average 283 mg l-1) of slightly weathered, finely ground bedrock particles into coastal waters during the summer. Approximately 15% of this SPM is exported within a low-salinity surface plume into Bransfield Strait. Based on our data, an estimated 12 mg m-2 yr-1 of FeA is exported from the South Shetland Island land surface (ice-free and subglacial areas) to the surrounding coastal waters. Extrapolated to an area of 2.5x104 km2, this FeA input is comparable to the contribution from icebergs and c. 240-fold higher than aeolian input via dust. An observed rise in local sediment accumulation rates suggests that glacial erosion has been increasing over recent decades and that (sub-)glacially derived SPM is becoming more important as a source of iron to the Southern Ocean.

The current status of Antarctic Odontocetes – sperm whales Physeter catodon, killer whales Orcinus orca, long-finned pilot whales Globicephala melaena, hourglass dolphins Lagenorhynchus cruciger and poorly known species of beaked whales (family Ziphiidae)–were studied in Anatarctic waters using data gathered in sighting surveys conducted from 1976/77 to 1987/88. Temporal variation in density demonstrated the different migration patterns by species, especially between sperm whale and killer whale. Spatial distributions during mid-summer demonstrated different peaks of occurrence for each species by latitude that suggest possible segregation between the species. Killer whales occur mainly in the very southernmost areas, sperm whales in the southern half of the study area, beaked whales (mostly southern bottlenose whales Hyperoodon planifrons) ranged over a wide area, and long-finned pilot whales and hourglass dolphins were mainly in the northern regions of Antarctic waters. Several longitudinal peaks of occurrence and apparent distribution gaps were identified for sperm, beaked and killer whales. Abundance estimates for south of the Antarctic Convergence in January are based on line transect theory and were 28 100 animals (coefficient of variation CV 0.18) sperm whales, 599 300 (0.15) beaked whales (mostly southern bottlenose whales), 80 400 (0.15) killer whales, 200 000 (0.35) long-finned pilot whales, and 144 300 (0.17) hourglass dolphins. Based on this, biomass of these species were estimated as 0.77 (sperm whales), 2.70 (beaked whales), 0.32 (killer whales), 0.16 (long-finned pilot whales) and 0.01 (hourglass dolphins) million tonnes. Consumption of food (mostly squid) by the Odontocetes is estimated as 14.4 million tonnes with 67% of the total consumed by beaked whales. Indirect consumption of Antarctic krill through the predation of squid by beaked whales is estimated to be c. 24 million tonnes. This value is similar to the estimate of krill consumption by penguins in the Antarctic (33 million tonnes). Odontocetes, especially southern bottlenose whales, are suggested to have a much greater role in the Antarctic ecosystem than has previously been considered.

In order to reconstruct past changes in penguin populations we performed geochemical analyses on a penguin ornithogenic sediment core DG4 retrieved from a lake catchment on Gardner Island, Vestfold Hills. P, Se, F, S, As, Sr and Cu in DG4 were identified as the bio-element assemblage by R-clustering analyses on the elemental concentrations and comparisons with those in bedrock and fresh penguin guano. Factor analysis on the levels of these bio-elements in the core permitted a reconstruction of variations in historical penguin populations at Gardner Island spanning the past 8500 years. The penguin population showed significant fluctuations, reaching its highest density between 4700–2400 calibrated years before present. This coincides with evidence for a late Holocene warm period in the Vestfold Hills, similar to that associated with the late Holocene penguin optimum recorded in the Ross Sea and Antarctic Peninsula regions.

The Rauer Islands contain more than fifty shallow lakes and small ephemeral ponds. Despite their proximity to the Vestfold Hills - one of the most diverse and intensively studied lake districts of eastern Antarctica - the lakes of the Rauer Islands have remained undescribed. In this study the physical and chemical limnology and biology of ten lakes is presented and their species-environment relationships explored using multivariate statistics. Analyses of chemical and biological data indicate that the Rauer Islands form a distinct limnological province amongst the lakes of the Prydz Bay oases. Salinities range from hypo- to hyper-saline with an ionic order close to that of seawater. Deviance from this order indicates either an earlier origin for some of the most hypersaline lakes when compared with the Vestfold Hills, more rapid evaporation vs precipitation or differences in the sources of ions resulting from isostatic history. With fluctuating salinities, winter water temperatures below –10°C, seasonal ice and slush formation, desiccation and high levels of solar radiation, the lacustrine environment presents considerable abiotic challenges for biological survival. Results indicate that there is little or no planktonic flora in the lakes and no zooplankton were encountered. Despite this, analyses of pigments, diatoms and other micro-algae revealed an active and diverse benthic biota characterized by filamentous cyanobacteria with interstitial algae. Thirty-eight diatom taxa, and a selection of Chlorophyta and Xanthophyta were detected amongst the cyanobacteria. Clusters in the diatom data correspond to salinity. Further analyses of the relationships between the biota and their environment revealed some of the strategies employed for survival. In particular, the synthesis of scytonemin was detected. This pigment is known to function as an extracellular UV sunscreen which protects cyanobacterial cells against damage by ultraviolet radiation. These results support the hypothesis that environmental extremes and biogeographical isolation control the biology of these lakes.

The Antarctic silverfish Pleuragramma antarcticum Boulenger is the dominant fish species in the high Antarctic zone, playing a key role in the Ross Sea midwater shelf ecosystem. Unlike other notothenioids, it is holoplanktonic species, spending its entire life cycle in the water column. Early life stages of P. antarcticum are generally found in the upper 200 m and their spatial distribution is largely affected by water masses and general circulation. To understand better the mechanisms involved in the geographical distribution of the Antarctic silverfish within the western Ross Sea, an analysis of abundance and distribution was carried out in relation to oceanographic conditions. Samples were collected in summer during the 1998, 2000 and 2004 Italian cruises, covering the majority of the western sector of the Ross Sea. Overall 127 stations were sampled using standard plankton nets for biological samples and CTD and XBT to record abiotic parameters. Although all surveys were in December–January, the yearly results differed in terms of relative abundance of larval developmental stages and of oceanographic characteristics. The 1997–98 samples were characterized by very low abundance overall and by the virtual absence of early larvae. In summers 1999–2000 and 2003–04 the abundance of P. antarcticum was one order of magnitude higher than in the earlier season. In 1999–2000 catches were mainly composed of pre-flexion larvae and late postlarvae, while in 2003–04 catches were made up of pre-flexion larvae and juveniles. In January 2000 the Ross Sea summer polynya was fully open as the pack ice was almost completely melted, whereas in January 1998 and 2004 the opening of the polynya was considerably delayed. As a consequence, a delay in phytoplankton blooms and a decrease in primary production were observed in the summer seasons 1998 and 2004 with respect to 2000. The spatial distribution of early life stages, that were confined to the continental shelf and shelf break of the Ross Sea, generally appeared to be positively influenced by transition zones (oceanographic fronts). In addition, most of catches were recorded on or in close proximity to the banks (Pennell, Mawson, Ross and Crary) that characterize the continental shelf of the Ross Sea. On the basis of present findings and literature data, a link between the general circulation in the western Ross Sea and the distribution pattern of the early life stages of P. antarcticum has been developed.

As baleen whales recover from severe exploitation, they are probably subject to a wide variety of threats within the Antarctic marine ecosystem, including directed take. Here we review both the management and current status of Antarctic baleen whales and consider those threats likely to impact on them. Threats range from global problems - marine pollution and climate change - to localized issues including shipping, habitat disturbance, unregulated wildlife tourism and fishery activities. We identify the most pressing anthropogenic threats to baleen whales including scientific whaling and climate change. It is unclear whether current management approaches will be able to effectively encompass all these threats while also accounting both for the differing levels of scientific understanding and for the differing recovery rates of the whale species. For management we recommend the following: 1) incorporation of both ecosystem considerations and the suite of identified threats not limited to direct take, 2) identification of measurable indicators of changes in whales that allow more certainty in monitoring of populations and the environment, and 3) recognition of significant relationships between baleen whales and habitat features to provide information on distribution and use.

We review the current scientific knowledge about Antarctic Blue Ice Areas (BIAs) with emphasis on their application for palaeoclimate studies. Substantial progress has been made since the review by Bintanja (1999), in particular dating the archive of ancient ice found on the surface of BIAs has progressed with advances in 14C measurements, tephrachronology, and geomorphological evidence giving better constraints to more sophisticated ice flow models. Flow modelling also provides information about past changes in ice flow velocities, accumulation rates and ice sheet elevation. The availability of gas composition in vertical cores from BIAs allows matching to well-dated global records of greenhouse gas variability over the last glacial-interglacial cycle and longer. It is clear from the limited number of studies to date that BIAs from different regions have quite different histories of formation and preservation, and that they are intimately linked to the response of their surrounding ice sheets to climate variability on glacial-interglacial time-scales. Looking to the future, climate records from BIAs are expected to provide information on variations in Southern Ocean processes as well as ice sheet evolution within the East Antarctic ice sheet at the thermal transition from cold based to warm based ice.

Field measurements of CO2 exchange were made with an infra-red gas analyser system on lichens at Bailey Peninsula, Wilkes Land, continental Antarctica. It has been demonstrated that Usnea sphacelata, a prominent element of the cryptogamic vegetation of this area, became photosynthetically active at temperatures below 0°C when the thalli were covered by drifted snow. Carbon dioxide uptake was detected down to −10°C. The carbon production during such a ‘frost’ day was considerable for a slow-growing Antarctic lichen. The importance of snow for production in lichens is emphasized. The mechanism of water uptake when the thalli are frozen needs further investigation.

The synoptic origins of precipitation on the western side of the Antarctic Peninsula over the one year period March 1992 to February 1993 are investigated using meteorological observations, satellite imagery and analyses produced by the UK Meteorological Office. Precipitation at Rothera Station was found to occur at 30% of the synoptic reporting time with 80% of precipitation reports being associated with cyclonic disturbances. Although three quarters of all precipitation reports were for snow, the proximity of Rothera to the zone of maximum cyclonic activity meant that incursions of mild air produced rain in all seasons. During the year 95% of all precipitation was classed as slight. Variability of precipitation on the intraseasonal timescale was highly dependent on the synoptic-scale circulation. The most common synoptic situation for precipitation was a frontal cyclone over the Bellingshausen Sea which accounted for 38% of all precipitation events and 62% of the moderate and heavy precipitation reports. Of the extra-tropical cyclones that gave precipitation 49% were found to have developed south of 60°S. None of the precipitation at Rothera was attributable to mesocyclones. Snow stake measurements from Rothera were a poor indicator of precipitation as a result of blowing snow.

Soil samples from eight sites at Marble Point and Pram Point, McMurdo Sound region, contaminated by human activities were examined for heavy metal content, using sequential extraction methods. The redistribution of lead, zinc and copper arising from point sources of these metals was demonstrated. The levels found are not considered to represent serious pollution but do indicate that human activities can change the chemistry of the Antarctic environment in localized areas.

In investigating the extent of genetic diversity in Antarctic mosses the RAPD technique has proven especially useful in demonstrating that these mosses exhibit extensive genetic variation (levels being similar to those in temperate regions), and that within-colony variation is apparently caused not only by immigration and establishment of propagules from elsewhere, but also by mutagenesis. Dispersal of these mosses can also be followed using the RAPD technique; both short-distance dispersal by wind or water (depending on the moss species) and longer distance dispersal by wind across the ice cap has been demonstrated. Relationships with temperate mosses of the same species are being investigated to determine the origins of Antarctic populations. Genetic technology is also facilitating the taxonomic identification of moss specimens which cannot be identified morphologically due to phenotypic plasticity in Antarctica. Together, these genetic studies are starting to provide information of fundamental scientific importance for understanding the evolution, origins and dispersal mechanisms of Antarctic mosses, and their response to climate change.

Data from eight CTD casts and two one-year long current time series collected at 8 and 60 m above the seafloor of a sediment drift, off the Pacific Margin of the Antarctic Peninsula are presented, with special emphasis on bottom boundary layer dynamics and processes relevant to sediment settling and re-suspension. The water masses over the drift are characterized, including also a comparison with other measurements available from that region. The south-westward flow along the continental rise exhibits a strong topographic (bathymetric) control in the near-bottom current regime. A consistent mean flow deflection between an upper and lower current regime suggests that only the lower regime falls within a bottom (turbulent) Ekman layer. The bottom current regime is not energetic enough to maintain the coarse sediment fraction in suspension. The absence of evidence for a nepheloid layer justifies the assumption that most sediment was supplied to the margin during glacial periods. Two events, with peak velocities of up to 20 cm s−1, are associated with barotropic eddies shown as negative (cyclonic) mean sea level anomalies detected by ERS/TOPEX satellite altimeters. These energetic bottom current pulses may give way to episodic sediment re-suspensions of the sortable (non-cohesive) part of the sediment, thus exerting a minor role in redistributing fine sediments through the mean flow regime.