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.

The soils of the Seabee Hook area of Cape Hallett in northern Victoria Land, Antarctica, were mapped and characterized. Seabee Hook is a low-lying gravel spit of beach deposits built up by coastal currents carrying basalt material from nearby cliffs. Seabee Hook is the location of an Adélie penguin (Pygoscelis adeliae) colony which influences the soils with additions of guano, dead birds, eggshells and feathers. A soil-landscape model was developed and a soil association was identified between the soils formed on mounds (relict beach ridges) favoured by penguins for nests (Typic Haplorthel) and the soils in the areas between the mounds (Typic Haplorthel/Typic Aquorthel). Soils formed on the mounds inhabited by penguins contained guano in the upper 50 cm, overlying sub-rounded beach-deposited gravel and sand. Soils between mounds had a thin veneer (< 5 cm) of guano overlying basaltic gravelly sand similar to that in the lower parts of the mound soils. The soils had high concentrations of nitrogen, organic carbon, phosphorus, cadmium, zinc, copper, and increased electrical conductivity, within horizons influenced by penguin guano. Five buried penguin bones were collected from the base of soil profiles and radiocarbon dated. The dates indicate that Seabee Hook has been colonized by penguins for at least 1000 years.

The Ahlmannryggen-Borgmassivet area of western Dronning Maud Land comprises a relatively undeformed, unmetamorphosed sequence of sedimentary-volcanogenic rocks, the Ritscherflya Supergroup, intruded by a suite of continental tholeiites, the Borgmassivet Intrusions. New Rb-Sr and Sm-Nd whole rock data from the Högfonna Formation at Grunehogna indicate a depositional age of ≈1080 Ma, the first reported direct dating of any member of the Ritscherflya Supergroup. These rocks are interpreted as a molasse-type deposit following the Kibaran orogeny at 1200–1100 Ma, and correlation is made with the Umkondo and Koras groups of southern Africa. The Ritscherflya Supergroup is intruded by the Grunehogna and Kullen sills; the ≈1000 Ma Grunehogna sill intruded unconsolidated sediments, causing partial melting of the sediments. Rb-Sr data from the Kullen sill yield an age of 1429 Ma, clearly inconsistent with these data. Combined Sr and Nd data are compatible with crustal contamination of this sill, producing a Rb-Sr pseudo-isochron with no geological age significance. By comparison with other outcrops of the Borgmassivet Intrusions at Robertskollen and Annandagstoppane, it is concluded that contamination and pseudo-isochrons may be responsible for the wide range in reported ages older than 1000 Ma. Thus the intrusive age of the Borgmassivet Intrusions is concluded to be ≈1000 Ma old. Nd model age data indicate that all rock types were ultimately derived from material separated from a depleted mantle source at ≈2200 Ma.

The Antarctic marine ecosystem contains low concentrations of a range of hydrocarbons, overwhelmingly biogenic in origin. The low natural levels of hydrocarbons and the small amount of local human activity make the Antarctic marine ecosystem suitable as a yardstick against which future global pollution by hydrocarbons can be assessed. At present, contamination is very low and difficult to resolve against the background. Local pollution is restricted to a very few events. A systematic programme with a clear definition of the natural background is proposed to monitor both global and local pollution.

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.

We map polygonally patterned ground formed in sublimation tills that overlie debris-covered glaciers in Mullins Valley and central Beacon Valley, in southern Victoria Land, Antarctica, and distinguish five morphological zones. Where the Mullins Valley debris-covered glacier debouches into Beacon Valley, polygonal patterning transitions from radial (orthogonal) intersections to non-oriented (hexagonal) intersections, providing a time-series of polygon evolution within a single microclimate. We offer the following model for polygon formation and evolution in the Mullins Valley system. Near-vertical cracks that ultimately outline polygons are produced by thermal contraction in the glacier ice. Some of these cracks may initially be oriented radial to maximum surface velocities by pre-existing structural stresses and material weaknesses in the glacier ice. In areas of relatively rapid flow, polygons are oriented down-valley forming an overall fan pattern radial to maximum ice velocity. As glacier flow moves the cracks down-valley, minor variations in flow rate deform polygons, giving rise to deformed radial polygons. Non-oriented (largely hexagonal) polygons commonly form in regions of stagnant and/or near-stagnant ice. We propose that orientation and morphology of contraction-crack polygons in sublimation tills can thus be used as an indicator of rates of subsurface ice flow.

Molecular analysis of phytoplankton population structure has lagged behind other groups and has usually been inferred from physiological data determined from relatively few clones. Nearly every physiological measurement has shown that no single clone of any phytoplankton species can be considered truly representative of that species. One important reason why studies of phytoplankton population structure are perhaps 20 or more years behind those of other organisms is because of the necessity to establish clonal cultures prior to genetic analysis and the inability to perform fine-scale sampling under most conditions. Isozyme analysis, performed for a few species, has revealed heterozygosity between populations. In addition, fingerprinting analyses, such as Random Amplified Polymorphic DNAs (RAPDs) or multi-locus probes, have shown that phytoplankton blooms are not mono-clonal, are highly diverse and isolates are related by geographic origin. In the Southern Ocean, only two studies have been made of the population structure of phytoplankton. The first, based on quantitative genetic analysis of morphometric features, suggests that there is sufficient genetic variation in populations of Thalassiosira tumida to allow speciation in terms of major shifts in morphology under conditions of continued directional selection. The second, using sequence data from the noncoding regions of the internal transcribed spacer region (ITS) in the ribosomal cistron as a molecular marker, shows that populations of Phaeocystis antarctica within continental water masses are homogenous with little evidence of population structure. Populations found within the Antarctic Circumpolar Current are genetically distinct from others, suggesting the currents also play an important role in determining population structure in phytoplankton populations.

Much of Antarctica's Devonian to Jurassic geological history is interpreted from the study of the Beacon Supergroup in the central Transantarctic Mountains. The upper part of the succession has been extensively investigated, although, few studies focus on the basal rocks. Deposition occurred within a Transantarctic basin believed to have extended along the edge of the East Antarctic Craton in early Beacon time, either as a marginal, passive margin, or a cratonic basin. Early basinal deposits include the Devonian Taylor Group and Upper Carboniferous–Lower Permian glacial sediments. Previous studies concluded that the Taylor Group in CTM was deposited as a continuous sheet across the low-relief Kukri Erosion Surface that developed on the planed Ross orogenic belt. These interpretations also concluded that late Palaeozoic glaciation truncated the Devonian sheet. New data suggest that this view, and current models for the early Beacon basin, maybe incorrect. Lithofacies, palaeocurrent orientations, sandstone composition, and stratigraphical relationships of central Transantarctic Mountains rocks suggest that deposition occurred within two intermontane or successor basins following post-orogenic uplift of the Ross terrain. Segregation of lithofacies and onlap of Taylor Group rocks onto an undulating Kukri Erosion Surface show that a basement high separated non-marine deposits between the Byrd and Ramsey glaciers from marine sediment in the Ohio Range. Onlap of glacial rocks and palaeocurrent data suggest intermontane conditions continued until the Early Permian.

The survey concentrated on algal communities but also gathered information on mosses, lichens and microfauna. All 23 nunataks in the Rockefeller and Alexandra mountains (77°00′–78°30′S, 152°–154°W) were visited, including ones both with and without nutrient enrichment from bird colonies. Over 30 species of algae were recorded with Cyanobacteria and Chlorophyta dominant as in other regions of continental Antarctica. Diatoms were not found. The most frequent algae were Cyanothece aeruginosa, Gloeocapsa spp., Oscillatoriaceae, Nostoc sp., Pseudococcomyxa simplex, Stichococcus bacillaris, cf. Desmococcus vulgaris, Prasiola crispa and Prasiococcus calcarius. Although lichens were the most visually prominent vegetation, free-living algae occurred in the widespread ‘non-aquatic’ habitats as epilithic, chasmoendolithic and edaphic communities as well as being epiphytic on the sparse moss cushions. Aquatic habitats were few and there were only three small ponds on or adjacent to nunataks. On ablating ice, cryoconite ponds contained Homoeothrix cf. rivularis, recorded for the first time in Antarctica. Preliminary identifications show 23 species of lichens and six species of mosses. No mites and collembola were seen. Samples contained testate amoebae, ciliate protozoa, rotifers and tardigrades but no nematodes.

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.

Mount Melbourne in northern Victoria Land, Antarctica, is a glaciated 2733 m volcanic cone. The moss Compylopus pyriformis occurs on two small areas of steam-warmed snow-free ground near its summit. This moss species also occurs in temperate regions world-wide, but has not been recorded elsewhere in continental Antarctica. RAPD (Random Amplified Polymorphic DNA) studies of 26 samples of C. pyriformis from two areas of heated ground on Mount Melbourne showed there was genetic diversity within the population. Genetic evidence for dispersal between the two sites, together with some genetic variation within individual colonies, indicates a single colonisation event has probably occurred at this extremely isolated location followed by multiple mutations. A single sample of moss protonema was collected 25 years ago from steam-warmed ground near the summit of another volcano, Mount Erebus (3794 m), on Ross Island some 300 km south of Mount Melbourne. The moss could not be identified based on morphological and reproductive criteria, as all attempts to differentiate it to a recognisable gametophyte were unsuccessful. The RAPD technique has now shown it to be C. pyriformis, and closely related to the population on Mount Melbourne.

Southern Ocean palaeocirculation is clearly related to the formation of a continental ice sheet on Antarctica and the opening of gateways between Antarctica and the Australian and South American continents. Palaeoenvironmental proxy records from Southern Ocean sediment cores suggest ice growth on Antarctica beginning by at least 40 million years (Ma) ago, and the opening of Tasmania–Antarctic and Drake Passages to deep-water flow around 34 and 31 ± 2 Ma, respectively. So, the Eocene/Oligocene transition appears to mark the initiation of the Antarctic Circumpolar Current and thus the onset of thermal isolation of Antarctica with a first major ice volume growth on East Antarctic. There is no evidence for a significant cooling of the deep ocean associated with this rapid (< 350 000 years) continental ice build-up. After a long phase with frequent ice sheets growing and decaying, in the middle Miocene at about 14 Ma, a re-establishment of an ice sheet on East Antarctica and the Pacific margin of West Antarctica was associated with an increased southern bottom water formation, and a slight cooling of the deep ocean, but with no permanent drop in atmospheric pCO2. During the late Pleistocene on orbital time scales a temporal correlation between changes in atmospheric pCO2 and proxy records of deep ocean temperatures, continental ice volume, sea ice extension, and deep-water nutrient contents is documented. I discuss hypotheses that call for a dominant control of glacial to interglacial atmospheric pCO2 variations by Southern Ocean circulation dynamics. Millennial to centennial climate variability is a global feature, but there is contrasting evidence from various palaeoclimate archives that indicate both interhemispheric synchrony and asynchrony. The role of the Southern Ocean, however, in triggering or modulating climate variability on these time scales only recently received some attention and is not yet adequately investigated.

Magnetic screening as a cost-effective and non-time-consuming approach has been successfully carried out in Marambio soils and seems to be a suitable method for contamination assessment in Antarctic areas. Ferromagnetic minerals are found in most samples, and magnetite-like carriers are especially dominant in samples collected near pollution sources. Lead and zinc are the main trace elements that have adversely impacted on some areas in this station, both are end products from different pollution sources derived from fuel combustion and residues, solid waste, paints, etc. The correlation results between magnetic and chemical variables show moderate relationships varying from 0.409 to 0.663; this fact supports the use of magnetic parameters, such as magnetic susceptibility and bivariate ratios, for pollution monitoring. The magnetic properties, heavy metal contents, and related maps of these soils can be considered as a reference in the area for future temporal and/or spatial work.

The Larsemann Hills represent a low-pressure granulite terrain with a complex structural-metamorphic history that comprises two parts: 1) granulite facies D1 structures transposed within an early form surface that probably formed at 1000 Ma, and 2) a sequence of progressive, upper amphibolite to lower granulite facies D2–D6 structures that formed during the Pan-African at 500 Ma and were associated with the emplacement of granites and pegmatites with high-grade alteration zones. D2–D6 events comprise an early form surface that has been tightly folded and sheared twice after which it was warped and transected by discrete mylonites. D2–D6 assemblages are associated with decompression textures on D1 peak-assemblages, such as cordierite coronas on garnet + sillimanite in metapelite and plagioclase coronas on garnet in metabasite. This suggests that D2–D6 formed at slightly lower pressures than D1 structures. However, the spatial correlation between the coronas and alteration zones around pegmatitic intrusives indicates that the apparent decompression textures may have partly resulted from transient fluxes in water pressure following melt crystallization. Throughout East Antarctica tectonic provinces have been recognized in which the 1000 Ma tectonothermal events are identified as the main stage in the evolution, and Pan-African events are dismissed as a minor thermal overprint. Although the Larsemann Hills are small in area, they are representative of a great many granulite terrains in East Antarctica, and suggest that great care is needed in the structural-metamorphic analysis of such terrains to ensure the separation of tectonic stages before an interpretation of the tectonic path is attempted.

For land-breeding marine organisms such as seabirds, knowledge about their habitat use has mainly been gained through studies of breeding individuals that are constrained to return frequently to their breeding grounds. In this study we set out to measure whether: a) habitat selection in the non-breeding period predicts habitat selection in the breeding period, and b) whether breeding individuals concentrated their activity on the closest suitable habitats. Macaroni Eudyptes chrysolophus and gentoo Pygoscelis papua penguins, two marine predators with contrasting foraging strategies, were tracked from the Iles Kerguelen and their habitat selection investigated through Mahalanobis distances factorial analysis. This study presents the first data about gentoo penguins’ juvenile dispersal. For both species, results showed 6.9 times larger maximum ranges and up to 12.2 times greater distances travelled during the non-breeding period. Habitat suitability maps suggested both species made similar environmental selections whatever the period. Macaroni penguins targeted pelagic areas beyond the shelf break while gentoo penguins always remained over the shelf. We consider the ecological significance of larger scale movements made outside the breeding period and suggest that this non-breeding period is of particular interest when attempting to understand an animal's habitat selection.

In order to establish the environmental status of areas close to Antarctic stations it is necessary to document levels of contaminants present in these sites. Several petrogenic and pyrogenic sources have been reported for polycyclic aromatic hydrocarbons (PAHs) in Antarctica. In this work, levels of 25 PAHs were measured in suspended particulate matter (SPM), surface sediment and marine organisms (fish Notothenia coriiceps, bivalve Laternula elliptica and gastropod Nacella concinna) from Potter Cove. Total PAH levels from SPM were low and similar in all sites studied (30–82 ng g-1 dw), phenanthrene being the dominant compound (68–84%). The exception was an area close to the wharf where significantly higher values of light PAHs such as naphthalene, acenaphthylene, 2,3,5-trimethylnaphthalene and fluorene were detected, indicating the influence of recent fuel spills. PAH concentrations in surface sediments were generally low (37–252 ng g-1 dw) except for two sites (1762 and 1908 ng g-1 dw) which suggested an accumulation process associated with the water circulation pattern. Liver tissue of N coriiceps presented significantly higher PAH levels (257 ng g-1 dw) compared with gonads. The pattern of individual compounds from substrates and organisms suggests a petrogenic and low-temperature combustion origin.

Very little attention has been paid to quantifying ammonia (NH3) emissions from Antarctic marine animal excreta. In this paper, penguin guano and ornithogenic soils from four penguin colonies and seal colony soils were collected in coastal Antarctica, and laboratory experiments were conducted to investigate potential NH3 emissions and effects of environmental factors on NH3 fluxes. Ammonia fluxes were extremely low from the frozen samples. Significantly enhanced NH3 emissions were observed following thawing. The mean fluxes were 7.66 ± 4.33 mg NH3 kg-1 h-1 from emperor penguin guano, 1.31 ± 0.64 mg NH3 kg-1 h-1 from Adélie penguin guano and 0.33 ± 0.39 mg NH3 kg-1 h-1 from seal colony soils during the thawing period. Ammonia emissions from penguin guano were higher than those from ornithogenic soils during freezing-thawing cycles (FTCs). The temperature, pH, total nitrogen (TN) and drying-wetting conversion had an important effect on NH3 fluxes. For the first time, we provide a quantitative relationship between NH3 flux and temperature, TN and pH. Our results show that marine animal excreta and ornithogenic soils are significant NH3 emission sources. In coastal Antarctica, FTC-induced NH3 emissions might account for a large proportion of annual flux from marine animal colonies due to high freezing-thawing frequency.

The fate of ice biota released via meltwater into pools of seawater trapped between melting ice floes (crack pools) was followed in late January in the southern Weddell Sea. Low salinity crack pools shared the following features: nitrate exhaustion, high pH and POC/PON ratios, high bacterial biomass composed of large cells, and a dense algal assemblage dominated to over 90% by only two diatom species. It is suggested that this “climax stage” evolved from a nutrient rich, moderate biomass situation prevailing in high salinity crack pools, and is representative of summer succession of sea ice biota. “Overflow” production following nitrate exhaustion by the algae resulted in internal (lipid) and external (presumably mucus) carbon pools. The latter must fuel bacterial biomass build-up, as algal mortality appeared to be low. The large algal and bacterial stocks point to low grazing pressure exerted by phagotrophic protists, presumably due to poor food quality (e.g. high C/N ratios) and/or excessive mucus production. It is concluded that environmental selection of the abundant ice algal species occurs under conditions prevailing in the disintegrating ice cover during summer, which differ drastically from those generally referred to as characteristic of the sea ice habitat at large (a combination of low temperature, low light and high salinity).

Allozyme electrophoresis was used to assess genetic variability and differentiation in 22 populations of Gressittacantha terranova Wise (Hexapoda, Collembola) from a coastal area of Victoria Land between the Mariner Glacier and the Nansen Ice Sheet. Allelic frequencies were determined at five enzyme loci: Phi, Pgm, Hk, Mpi and Mdh. Levels of variability, estimated as rates of heterozygosity, were higher than those calculated for the same loci in taxonomically related and non-related species of non-Antarctic Collembola. Thus, in spite of the ecological simplicity of Antarctic terrestrial ecosystems, G. terranova is characterized by high levels of genetic variability, and the 22 populations could be divided into three geogaphic groups, separated by the Aviator and Campbell glaciers. Genetic differentaton reflects the geographic arrangement of the populations, suggesting that the glaciers are effective barriers to gene flow, and that the patchy distribution of collembolan species in Antarctica has the potential to induce, in the long term, microspeciation processes. Interestingly, detectable genetic differentiation was observed between six populations collected at Edmonson Point, even though these are very close to each other, indicating the impact of geographic isolation even within short distances. The only exception to the congruence between genetic and geographic structuring was provided by the population of Apostrophe Island, for which a recent introduction with individuals coming from southern populations is suggested.

Feeding behaviour, ecological role in the marine food web and population trends of the Antarctic shag Phalacrocorax bransfieldensis and the South Georgia shag P. georgianus in Antarctica are analysed. The diving depths and duration recorded for these shags are the deepest and longest among all flying birds in Antarctica and match deep dives performed by small Antarctic penguins. Individual shags of both sexes partition foraging depths and food resources, which might diminish intra-specific competition. Like other sub-Antarctic shags, P. bransfieldensis and P. georgianus are bottom feeders that prey predominantly on demersal fish. In the southern Scotia Arc and west Antarctic Peninsula, nototheniids, mainly Notothenia coriiceps, constitute their main prey. Shag partners alternate the time at sea and, as the energy requirements at the nest increase, they increase the number but reduce the duration of the feeding trips. A steady declining trend in the number of breeding pairs of both species has been observed in the last decade at several Antarctic localities; this phenomenon at the South Shetland Islands might be at least partially explained by the effect of the commercial fishery on their prey. In inshore shallow waters shags occupy the trophic niche of main predators of demersal fish and play an important ecological role as regulators of populations of particular fish prey that have marked site fidelity. The potential use of shags as biomonitors in Antarctica is discussed.