Possible effects of “El Niño” Southern Oscillation (ENSO) components “El Niño”and “La Niña“ on populations of southern elephant seals, Mirounga leonina L., are considered in this study. Information on pup weaning mass, collected at King George Island, South Shetland Islands, over a ten-year period (1985–94) was analysed with respect to the occurrence of ENSO and recent research in feeding ecology of this population in the Bellinghausen Sea. Weaning mass of elephant seals was found to be higher during “La Niña” and a lower during “El Niño”. Differences in weaning mass between sexes varied in different proportions during El Niño and La Niña. The teleconnection between tropical Pacific anomalies and the Bellinghausen Sea deserves further research, and our results suggest a way to study this phenomenon using data of elephant seal pups weaning mass as indicators of changes in food availability.

Body size was measured for 67 of the approximately 120 invertebrate species on Marion Island. These include more than 60% of the 29 acarine families, and more than 80% of the remaining terrestrial invertebrate species. Thus the data are regarded as representative of the entire invertebrate fauna of sub-Antarctic, Marion Island. Length–mass and fresh–dry mass relationships were calculated for orders, families and species to provide a means of estimating body size parameters for species in collections and those which are known from only a few specimens. A comparison of the regression slopes for the different taxonomic ranks indicates that it is better to use regressions from the lowest possible taxonomic level for prediction of body mass. Differences between length–mass relationships for Marion Island insects and continental assemblages raises the question as to the applicability of continental regressions to sub-Antarctic species. This study provides a useful means for estimating body size parameters for Antarctic and sub-Antarctic invertebrates and provides baseline data on an important species trait that seems to be changing with local and global environmental changes.

Ichthyoplankton sampling was conducted seasonally with 36 surveys between spring 1989 and spring 1992 in four bays in the Kerguelen archipelago: Morbihan, Baleiniers, Choiseul and Audierne. Golfe des Baleiniers is open to the shelf whereas Choiseul and Audierne are long fjords. Golfe du Morbihan is a very large and protected area open to the shelf at its eastern end. Larvae of neritic species were abundant outside whereas larvae of inshore species were abundant inside the Golfe du Morbihan. Larval Lepidonotothen squamifrons were detected during summer every year whereas larvae of Champsocephalus gunnari were observed in only two years, mainly in the northern coastal zone. For both species, our results support coastal spawning grounds in addition to those on the shelf slope. Larvae of the mesopelagic fish Krefftichthys anderssoni were dominant primarily during winter; this was linked to homogenisation of the water column over the shelf and the coastal zone. Larvae of Notothenia cyanobrancha were present throughout the year everywhere, which is linked to the year long pelagic earlylife-history phase.

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.

Lake Vanda, a perennially ice-covered Antarctic lake has a highly stratified structure with a pronounced density gradient from 45 m and is anoxic from 68 m down. In order to gain a greater understanding of the carbon cycling in the lake we attempted to measure sulphate reduction in the summer of 1994, but rates were below detectable limits of 1.2 × 106 mol sulphate yr−1. Therefore sulphate reduction was estimated by calculating the rate of sulphide diffusion from the anoxic zone. Sulphate reduction rates were estimated to be 17.7 × 103 mol sulphate yr−1, accounting for 30% of planktonic primary production over the whole lake, but over 100% of primary productivity in the deep chlorophyll maximum. Radiocarbon dating of organic matter in the sediment (565 ± 50 yr bp), suggests that little new organic carbon reaches the sediment from the upper water column. Oxygen diffusion into the anoxic zone could account for only 44% of sulphide reoxidation; therefore, alternative oxidizing potential presumably accounted for the remainder. Sulphate concentration may be controlled by the solubility limit for a mineral phase, perhaps gypsum, as it shows a positive correlation with conductivity. The sulphur species in the anoxic zone are highly enriched in 34S (sulphate δ34S = + 42 to + 46%0, sulphide δ34S = + 13.9%0) which may be explained by either selective removal of sulphide at the oxic/anoxic interface by precipitation of metal sulphides or previous loss ofH2S to the atmosphere. While sulphate reduction is an important part of the carbon cycle within the lake, the oligotrophic nature of Lake Vanda means that all microbiological process rates are very low. The data presented suggest a dynamic and complex history for Lake Vanda and are entirely consistent with present theories of the lake's history.

A new topographic database for King George Island, one of the most visited areas in Antarctica, is presented. Data from differential GPS surveys, gained during the summers 1997/98 and 1999/2000, were combined with up to date coastlines from a SPOT satellite image mosaic, and topographic information from maps as well as from the Antarctic Digital Database. A digital terrain model (DTM) was generated using ARC/INFO GIS. From contour lines derived from the DTM and the satellite image mosaic a satellite image map was assembled. Extensive information on data accuracy, the database as well as on the criteria applied to select place names is given in the multilingual map. A lack of accurate topographic information in the eastern part of the island was identified. It was concluded that additional topographic surveying or radar interferometry should be conducted to improve the data quality in this area. In three case studies, the potential applications of the improved topographic database are demonstrated. The first two examples comprise the verification of glacier velocities and the study of glacier retreat from the various input data-sets as well as the use of the DTM for climatological modelling. The last case study focuses on the use of the new digital database as a basic GIS (Geographic Information System) layer for environmental monitoring and management on King George Island.

Cold tolerance of the springtail Gomphiocephalus hodgsoni Carpenter (Collembola: Hypogastruridae) was studied at Cape Bird, Ross Island, Antarctica (77°13′S, 166°26′E). Microclimate temperatures indicate a highly seasonal thermal environment, with winter minima <–39°C. Snow cover significantly buffers both minimum temperatures and cooling rates. Gomphiocephalus hodgsoni survives low temperatures by avoiding freezing. Mean low group supercooling points (SCPs) ranged from –35.4°C in October to –28.3°C in January. The lowest SCP measured was –38.0°C. The high SCP group was very small, making up only 18% of the population in January. In October, G. hodgsoni had a very high glycerol content (>80 μg mg−1 dry weight), although this declined rapidly to low levels (c. 7–10 μg mg−1 dry weight) in January. Quantities of glucose and trehalose were low during October, but steadily increased throughout the summer. Haemolymph osmolality was exceptionally high (up to 1755 mOsm kg−1) at the end of November, but this rapidly declined to c. 500 mOsm kg−1 by late December. The presence of thermal hystersis proteins was indicated by both osmometry on haemolymph samples and recrystallization inhibition studies of springtail homogenates. There was a strong relationship between glycerol content and SCP, but the relationship between haemolymph osmolality, SCP and carbohydrates is uncertain.

Fifty-nine species of pycnogonids belonging to sixteen genera and eight families were collected during a cruise near Livingston Island and surrounding waters, from depths between 0 and 1019 m. The new species Ammothea bentartica is described fully, illustrated and compared with similar species. The family Nymphonidae had both the greatest number of species (20) and number of specimens (67% of 1201). The most abundant species were Nymphon charcoti and N. australe. Nymphon paucidens and Pallenopsis buphtalmus were collected for a second time. The collections increased the geographical distribution of five species and the depth range of seven species. This collection appears typical of the West Antarctic zone.

In January to March 1997, a RV Polarstern cruise that transected the Weddell Sea resulted in samples being taken in thick pack ice in the south-eastern Weddell Sea and then along the marginal ice edge towards the Antarctic Peninsula. Several ice types were thus sampled over a wide geographic area during late summer/early autumn. Common features of the first warm period was the occurrence of surface ponds, and that many floes had quasi-continuous horizontal gaps, underlying a layer of ice and metamorphic snow. With the onset of cold air temperatures in late February the gaps rapidly refroze. The calanoid copepod Stephos longipes occurred in all habitats encountered and showed highest numbers in the surface ice in summer, in the gap water during both seasons and in the refrozen gap water in autumn. Nauplii outnumbered copepodids in the surface ice and refrozen gap water, while in the gap water copepodids, mainly stages CI–CIII in summer and CII–CIV in autumn, comprised about 70% of the total population. The harpacticoid species Drescheriella glacialis did not occur in all habitats and was missing in surface ponds and new ice. Nauplii of D. glacialis were rarely found in gap water, but predominated in the refrozen gaps.

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.

The climatic and sea ice conditions of the Southern Ocean are highly variable within and between years, and a better understanding of the influence of climatic conditions on the various parts of the marine food chain is needed. This paper summarizes data on breeding success of a krill-dependent predator, the Wilson's storm petrel Oceanites oceanicus, in a colony on King George Island, South Shetland Islands, Antarctica, over four breeding seasons from 1995/1996 to 1999/2000. The seasons differed greatly in environmental conditions and in the resulting food availability which was reflected in inter- and intra-annual variations in feeding frequency. The breeding success was consequently variable. Starvation, the main cause of chick mortality in three out of four breeding seasons was associated with reduced sea ice cover in winter, which is known to depress food availability in the following breeding season. Food delivery rates also depended on the prevailing winds, which drive the transport of zooplankton-rich water masses. Snowstorms caused additional chick mortality in two out of four seasons when nest burrows became blocked. Implications for the use of Wilson's storm petrels for monitoring of krill are considered.

We report evidence of a large proglacial lake (Glacial Lake Wright) that existed in Wright Valley in the McMurdo Dry Valleys region of Antarctica at the last glacial maximum (LGM) and in the early Holocene. At its highstands, Glacial Lake Wright would have stretched 50 km and covered c. 210 km2. Chronology for lake-level changes comes from 30 AMS radiocarbon dates of lacustrine algae preserved in deltas, shorelines, and glaciolacustrine deposits that extend up to 480 m above present-day lakes. Emerging evidence suggests that Glacial Lake Wright was only one of a series of large lakes to occupy the McMurdo Dry Valleys and the valleys fronting the Royal Society Range at the LGM. Although the cause of such high lake levels is not well understood, it is believed to relate to cool, dry conditions which produced fewer clouds, less snowfall, and greater amounts of absorbed radiation, leading to increased meltwater production.

Magnetic properties of bulk sediment samples taken from three cores from the Scotia Sea, Antarctica were determined using a fully-automated variable field translation balance. Fine-grained detrital magnetite is identified as the principal carrier of remanence in these Upper Quaternary sediments which were deposited under the influence of the Antarctic Circumpolar Current. Inferred magnetite grain-size is consistent with published bulk grain-size data for these cores. Pseudo-single domain grains characterize Holocene samples, and larger, multi-domain grains occur in glacial samples from two of the cores, whereas samples from the northernmost core site show dominantly multi-domain behaviour.

New structural data from the northern Antarctic Peninsula suggest that reverse faults and folds affecting the Pedersen Nunatak beds of the upper Mesozoic–Lower Cenozoic Larsen Basin succession were produced by transpressional forces acting parallel to the Weddell Sea coast of the Antarctic Peninsula during mid-Cretaceous compression of the Larsen Basin. At Pedersen Nunatak, Larsen Basin rocks are deformed into a series of synclines and anticlines that are cut by reverse faults.

The limnology and sedimentary diatom flora of fourteen lakes and ponds from the Windmill Islands, East Antarctica, is presented. Saline lakes, saline ponds and freshwater ponds are represented in this dataset. The Windmill Island lake diatom flora represents an intermediate floral assemblage between that of the freshwater lakes of the Larsemann Hills and the saline lakes of Vestfold Hills, East Antarctica. Variations within this assemblage are related to water chemistry variables in the Windmill Island lakes. In particular, a lakewater salinity/phosphate gradient can explain the variation observed in the sedimentary diatom flora of the lakes and ponds included in this study.

Sixty-three radiocarbon dates on organic remains from 21 abandoned colonies of chinstrap (Pygoscelis antarctica) and Adélie (P. adeliae) penguins on 12 islands in the Antarctic Peninsula region are evaluated for determining the occupation history of penguins in this region. This record also provides a means for assessing sea-level change, glacial advances and retreats, and population responses by penguins to these events. All conventional dates were corrected for the marine-carbon reservoir effect by applying a ΔR = 700±50 BP and marine calibration curves. The 63 calibrated dates give 2σ ranges (95% confidence intervals) from modern to 5990 yr BP. These dates indicate progressively older occupations from north to south along the Antarctic Peninsula. No sites older than approximately 540 BP occur in the northern peninsula, either because they have not yet been found or older sites have been destroyed by solifluction and glacial scouring. Three dates from one locality near Rothera Point, Adelaide Island, also were calibrated with a ΔR = 750 ± 50 and 800 ± 50 BP. No difference was found between calibrated dates using these two other ΔR values, indicating that local corrections for variation in upwelling intensity may not be necessary.

In November 1994 epibenthic sledge samples were taken in the Beagle Channel. This study presents the first systematic account of Tanaidacea of the Beagle Channel and an adjacent area on the Atlantic continental slope. The material of this part from the Magellan Strait comprised 2175 specimens and 27 species of eight families of Tanaidomorpha and two families of Apseudomorpha. Eleven species were sampled in the Magellan region for the first time. The genus Stenotanais (Anarthruridae) was reported for the first time in the Southern Hemisphere and, the bathymetric range of seven species was extended. The tanaidacean fauna in the Beagle Channel is highly heterogeneous with 36 tanaidacean species now known from the Magellan region. On the basis of a zoogeographic comparison of the Magellan region with sub-Antarctica and Antarctica, Sieg's (1988) hypothesis of a phylogenetically young, derived Antarctic tanaidacean fauna is examined and the zoogeographic relationship between the Magellanic Tanaidacea and the Antarctic tanaidaceans is discussed.

The Pedersen Formation includes conglomerate-dominated successions exposed on Pedersen Nunatak (142 m thick) and southern Sobral Peninsula (750–1000 m thick). As re-defined here, it also includes mudstone and sandstone in tectonic contact with Nordenskjöld Formation strata on a nunatak north of the Sobral Peninsula conglomerate outcrops. 40Ar/39Ar ages and palynological data indicate an early Aptian age for the lower part of the formation on Sobral Peninsula. The Pedersen Nunatak strata have yielded conflicting age determinations, although an Early Cretaceous age seems likely. The Sobral Peninsula conglomerates are lithologically similar to, and possibly coeval with, basal Gustav Group strata (Lagrelius Point Formation) on James Ross Island. Although further field sampling is required to resolve the age of the Pedersen Nunatak strata, on present evidence the Pedersen Formation appears to form part of the same tectono-stratigraphic unit as the lower part of the Gustav Group, and we therefore propose that it be included in that group.

Two short gravity cores were retrieved to obtain palaeoclimatic information from Maxwell and Admiralty bays, King George Island, South Shetland Islands. AMS 14C age dates, sediment properties (grain size, TOC and CaCO3) and stable oxygen and carbon isotope compositions of benthiδ foraminifera (Globocassidulina biora) show downcore variations that characterize depositional conditions during the late Holocene. In particular, δ18O values of benthic foraminifera are lowest at approximately 2500 yr bp in both cores. Allowδ18O time-equivalent excursion in both cores is interpreted to reflect a distinct subglacial meltwater discharge intensified by warm climatic conditions. An increased proportion of fine-grained detritus and higher TOC in the cores at this level suggests that enhanced meltwater supply may have resulted in increased primary productivity. This meltwater discharge event provides evidence of climatic instability during the late Holocene at King George Island.