This study aimed to use nutrients in lake inflows as proxies for assessing human impact and separating this from natural transformations of material in the soil active layer. Nutrients, conductivity and δ18O were monitored in surface and subsurface (using ceramic tipped piezometers) lake inflows during summer in near natural and human impacted catchments. The nutrient levels were highly variable but generally higher during the last weeks of the flow, in both subsurface waters and in human impacted catchments. Up to 2000 μgN l−1 subsurface dissolved inorganic nitrogen (DIN) was measured in human impacted catchments but only 315 μg N l−1 in natural catchments. Subsurface levels of dissolved reactive phosphorus (DRP) were up to 310 μgP l−1 in natural catchments and up to 108 μgP l-1 in human impacted catchments. The maximum levels of both DIN and DRP in surface inflows were much higher in human impacted than in natural catchments. Conductivity and δ18O data showed general enrichment of snowbank meltwater presumably through evaporation from the active layer. This combined with fluctuating nutrient levels in catchment waters indicated that soil brines and decaying organic matter of natural and human origin were possible sources for nutrients and other salts. Marked salinization and substantially increased DIN levels near the research stations indicated that lake waters were receiving nutrients generated by humans.

The diet of breeding Antarctic shags (Phalacrocorax bransfieldensis) was investigated at four colonies on the Danco Coast, Antarctic Peninsula, by the analysis of 616 pellets (regurgitated casts) collected from December 1997 to February 1998. Overall, demersal-benthic fish were the most frequent and important prey at all the colonies, followed by octopods and gastropods. Amongst fish, Notothenia coriiceps was the main prey in all of the sampling sites, followed in similar importance by Gobionotothen gibberifrons at Cape Herschel, Primavera Island and Midas Island and in less importance by Harpagifer antarcticus at Py Point. There were marked differences among colonies in the size of the fish consumed. The largest and the smallest specimens were eaten by shags from Midas Island and Py Point respectively. This was mainly influenced by the number of specimens of the smallest fish species, H. antarcticus, consumed at Py Point. The differences in the diet composition may be related to the different foraging areas used by the shags. Results from this study differ from previous studies around the Antarctic Peninsula. The shags at the Danco Coast preyed markedly more intensively than those at the South Shetland Islands on G. gibberifrons. This finding reflects the low abundance of this fish species in inshore waters (< 100 m depth) at the South Shetland Islands and supports the use of the Antarctic shags to monitor trends in local populations of coastal fish species.

Reaction to the presence of prey, after visual stimulation, was tested in the Antarctic nototheniid fish Notothenia neglecta Nybelin under four different simulated Antarctic seasons - photoperiods of 24 hours light, 22 light/2 darkness, 12 light/12 darkness, and 24 hours darkness. Live Lepidonotothen nudifrons were used for visual stimulation, with exclusion of chemical and mechanical signals. The photoperiod showed significant correlation with the number of individuals stimulated and with the latency time of the first response to the presence of prey, but not with the number of attacks or pursuits. However, there were more pursuits in darkness than in light. Notothenia neglecta presumably perceive a large spectrum of wavelengths, because they had the shortest reaction time under red light, used to simulate darkness. The tests proved that N. neglecta are capable of detecting prey using only vision, in all seasons of the year, but that the optimal reactions occur in a photoperiod corresponding to the Antarctic autumn or spring.

Selected sterols (coprostanol, epicoprostanol, cholesterol, cholestanol), stanone (5ßcoprostanone) and linear alkylbenzenes (LABs) were measured in the surface sediments near Ferraz station sewage outfalls, in Admiralty Bay, King George Island, South Shetland Islands. during the summer of 1997/98 using GC-FID and GC-MS. Total sterol concentrations varied between 0.21 and 10.4 μg g−1 dry sediment. Cholesterol was the major sterol at all sites, except at the sewage outfall, where coprostanol predominated. The concentration of coprostanol varied between 0.03 and 6.14 μg g−1 dry sediment, but the majority of the samples contained levels below 0.13 μg g−1 dry sediment. The parameters coprostanol+epicoprostanol in total sterols, coprostanol/epicoprostanol ratio versus % of cholesterol in total sterols and versus 5ß-coprostanone concentration were used to identify the sewage impacted locations in the study area. Only sites extending to 50m from the sewage outfall exhibited a sterol signal indicating sewage input. Total LABs varied from <0.60 to 11.8 ng.g−1 dry sediment with the maximum level at the sewage outfall. Faeces from different species of seals all contained large amounts of cholesterol and some 5ßcoprostanone. Relatively low levels of coprostanol and high levels of cholesterol observed in distant sites could be attributed to natural sources such as marine mammals.

Epishelf lakes, positioned between ice-free areas and floating ice shelves or glaciers, are unusual tidal, but largely freshwater, environments found in both the Arctic and the Antarctic. The greatest concentration of these lakes is in the Bunger Hills, East Antarctica (66°S, 100°E). We present and discuss temperature and salinity profiles for five epishelf lakes from this region, most of which show unusual properties. White Smoke Lake is fresh and cold (<0.1°C) throughout; Lake Pol’anskogo has two basins, one fresh and cold, the other saline and warm; ‘Southern’ Lake is cold and saline at depth; Transkriptsii Gulf has a deep, warm saline layer; and ‘Northern’ Lake is relatively warm throughout. The structures of these lakes can be explained in terms of a simple model in which the isolated saline water evident in three of the lakes entered the basins through the connection to the marine waters during periods of reduced freshwater input. By dating these marine incursions, periods of reduced melt, presumably due to colder temperatures, can be determined.

Sanctioned longline fishing for Patagonian toothfish around the Prince Edward Islands (a globally important seabird breeding site) commenced in 1996 following high levels of Illegal, Unregulated and Unreported (IUU) fishing. Independent fishery observers accompanied all but two sanctioned trips between 1996 and 2000, allowing a thorough understanding of the impact of this fishery on seabirds. Overall, white-chinned petrels Procellaria aequinoctialis were by far the most frequently killed species. However, during the first year, when lines were set during the day and night, a significant number of albatrosses (particularly grey-headed albatrosses Thalassarche chrysostoma) were also killed. Birds were caught almost exclusively during their breeding seasons and most birds killed were breeding adult males from the Prince Edward Islands. Albatrosses and giant petrels were caught almost exclusively during day sets, whereas catch rates of white-chinned petrels did not differ between day and night sets. Albatrosses were caught closer to the islands than white-chinned petrels. Most white-chinned petrel carcasses were hooked in their wings and bodies, whereas albatrosses were caught most frequently in their bills and contained large numbers of baits. Rates of seabird bycatch in the sanctioned fishery decreased from 0.19 birds per 1000 hooks to 0.034 birds per 1000 hooks during the time of this study. This was probably mainly due to stricter implementation of mitigation measures and a progressive movement farther away from the islands over the years. We estimate that the combined impact of legal and IUU longline fishing around the Prince Edward Islands over the past four years could have resulted in between 7000 and 17 000 seabird mortalities and could have had significant impacts on the breeding populations of several seabird species breeding on the Prince Edward Islands. This was mainly due to high levels of IUU fishing during 1996/97.

Australodelphis mirus (Delphinidae n. gen., n. sp) is a small extinct Early Pliocene dolphin known from five individuals from shallow-water strata of the Sørsdal Formation, Vestfold Hills, East Antarctica. Australodelphis mirus is the first higher vertebrate named from the Oligocene-Pleistocene interval on land in Antarctica, and is the first cetacean fossil from the polar margin of circum-Antarctic Southern Ocean that postdates the break-up of Gondwana. The dolphin is convergent in skull form with some living beaked whales (Mesoplodon spp.; Family Ziphiidae) in its long, narrow and toothless upper jaw and face, but skull suture patterns, basicranial sinuses, and ear-bones indicate close relationship with living long-beaked dolphins (Delphinidae). Australodelphis mirus perhaps was a suction-feeding squid-eater which occupied quiet near-shore shelf waters influenced by glaciers but probably lacking major sea-ice. Possible ecological equivalents of A. mirus (small ziphiids, long-beaked dolphins) do not occupy Antarctic waters today, perhaps excluded by cold conditions and/or sea-ice cover. Earlier Pliocene cetaceans worldwide reveal significant extinct and sometimes bizarre taxa, and extant families with ranges quite different from today, pointing to climate-related changes in cetacean ecology in the last 2–3 million years.

The study of polychaetes from the Marion Dufresne expedition to the Îles Crozet in 1982 provided 45 species from depths ranging from 50–1055 m. The most abundant was Eunice pennata, found at all depths and in all types of substratum in about 66% of the samples. This species with Laetmonice producta, Harmothoe spinosa and Lanice marionensis made up over 50% of all polychaete specimens. A homogenous polychaete assemblage dominated by the above mentioned group of species was encountered in the shallower stations (100–300 m). A mosaic-like and less abundant polychaete fauna with some characteristic, abundant species: Amage sculpta, Laetmonice wyvillei, Leanira quatrefagesi and Melinna cristata was encountered in the deeper stations (300–1055 m). Clear similarities between the polychaete fauna of Îles Crozet and soft-sediment polychaete assemblages of Marion and Prince Edward Islands were noticed. No such affinity was encountered with the polychaete fauna of Îles Kerguelen. Their position in relation to the Polar Front as well as possible differences in bottom deposits (calcareous versus siliceous) may in part explain these dissimilarities. The biogeographical status of Kerguelen Islands is also discussed.

Two mitochondrial DNA regions and seven microsatellite loci were examined in Patagonian toothfish from three locations in the Southern Ocean (Macquarie Island, five collections; Heard and McDonald Islands, four collections; Shag Rocks/South Georgia area, one collection). Striking mtDNA heterogeneity was detected between the three fishing locations (FST=0.445, P<0.001), but spatial and temporal collections within the same location were not significantly different. No significant overall microsatellite differentiation between the three locations was apparent (FST=−0.009, P=0.785). However, some individual loci showed small but significant differentiation, which in each case was attributable to between rather than within-location differentiation. Greater differentiation of mtDNA can, in principle, be explained either by female philopatry and male dispersal, or by its greater sensitivity to changes in effective population size. The latter seems more likely as tagging indicates that toothfish is generally a sedentary species. The genetic heterogeneity between the three locations indicates restricted gene flow, with the fish at each location comprising independent units. Depletion in one location is therefore unlikely to be quickly replaced by immigration from another.

A net sampling survey was carried out for krill in a standard station grid around Elephant Island during 27 January to 4 February 2001. In comparison with recent years the station grid was extended south, where a large proportion of small size classes, one-year-old juvenile krill was found. Results show a spatial separation of the juvenile krill and the spawning stock, Krill density was significantly higher than during the past years (229 krill 1000 m−3 or 13.0 g m−2). The proportional recruitment index for the entire survey area for the 1999/2000 year class was R1 = 0.573, which is among the highest values recorded during the past 20 years. The maturation index (based on the proportion of gravid stages) was G = 0.99, indicating an early initiation of the spawning season. The results indicate a turning point after a succession of years with poor recruitment success and low stock biomass. This is thought to be the first step for a successful spawning event and a later potential recruitment success of the 2000/01 year-class. The spatial extent of the station grid is discussed in the light of a representative coverage of the stock and the estimated recruitment index.

A 51.85 m ice core collected from site LGB65 (accumulation rate 127 kg m−2 a−1, mean annual temperature −33.1°C) in Princess Elizabeth Land, East Antarctica, during the 1996–97 Chinese First Antarctic Inland Expedition has been analysed for chemical composition and oxygen isotope ratio. Based on the high definition of seasonal variations of major ions, the ice core was dated with errors within ± 3 years. The continuous sulphate analysis of the ice core provides an annually resolved proxy history of southern hemisphere volcanism in the past 250 years. High nssSO42−, concentrations seem to be well correlated to some explosive volcanic eruptions, such as Tambora (AD 1815), Coseguina (AD 1835), Krakatoa (AD 1883) and Tarawera (AD 1886). In comparison with other volcanic records, it seems that nssSO42− concentration data provide a better proxy for detecting volcanic activity than nssSO42− fluxes in low and intermediate accumulation regions, however, in high accumulation regions, small and moderate events may be more identifiable using of nssSO42− flux data.

A 2.7 m thick mid-Holocene sedimentary succession composed of alluvial fan and marine beach deposits is exposed at 14.4–17.1 m above sea level (a.s.l.) on the south-eastern coast of Potter Peninsula, King George Island (South Shetland Islands, Antarctica). The raised marine beach deposits contain a subfossil assemblage that includes remains of Adélie (Pygoscelis adeliae) and gentoo (P. papua) penguins, skua (Catharacta sp), seals (elephant seal Mirounga sp), and seaweed fragments. The palaeontological and palaeogeographical evidence allows us to infer that penguin rookeries were active on high cliffs of the Potter Peninsula during the marine beach sedimentation, which is dated to c. 4540–4450 reservoir-corrected 14C yr BP on the basis of radiocarbon dating on penguin bones. The data presented in this paper are in agreement with the Holocene palaeoenvironmental chronology known from Potter Peninsula, and suggest that marine birds and seals inhabited the coastal areas of King George Island probably during a mid-Holocene period of seasonally open marine conditions, which may coincide with a cooling period around Antarctica estimated from ice core records between 8000–4000 yr BP that preceded the “climate optimum” in the Antarctic Peninsula (4000–3000 yr BP).

This paper presents the results of the analysis of hydrological data of a 5-day mesoscale experiment (53 CTD casts) conducted during the XIIIth Italian Expedition to Antarctica (1997–98 cruise) in the framework of the CLIMA (Climatic Longterm Interaction for the Mass balance in Antarctica) Project of the Italian National Programme for Antarctic Research (PNRA). The experiment site was chosen for studying the dense water overflow in relation to the shelf-break in the central Ross Sea, after a large-scale synoptic survey, aimed to detect the general hydrological characteristics of the basin. A classical θ/S analysis was carried out for better understanding of the shelf-slope connection and the interactions between the water masses of this zone: the Circumpolar Deep Water (CDW) coming from the oceanic domain and the Ice Shelf Water (ISW) spreading from the Ross Ice Shelf (RIS) edge. Our results show the evidence of an overflow of dense water, originated on the continental shelf, on the shelf-break. This supercold water signal is found on the continental slope down to 1200 m depth. The shape of this tongue of modified ISW, whose thickness reaches up to 100 m, is very narrow, suggesting that the overflow occurs in very localized areas.

The Indian Institute of Geomagnetism (IIG) in 1982, 1986, and 1996, operated a Proton Precession Magnetometer (PPM) at its Antarctic stations Dakshin Gangotri/Maitri (located at ∼70°S, ∼12°E). Comparison of the average quiet-time value of total intensity F for these years with values of F obtained at the same geographic location (interpolated from iso-intensity contours of F on World Magnetic Charts and IGRF Maps) for earlier years, suggested that over the last 75 years at this location, F has dropped from ∼49 000 nT in 1922, to ∼40 000 nT in 1996 i.e. ∼120 nT per year. Further inspection at nearby Antarctic stations reveals a drop of ∼108 nT yr−1 at Novolazarevskaya, ∼100 nT yr−1, at Georg Forster and ∼95 nT yr−1 at Syowa; Mawson situated still further away shows a drop of ∼72 nT yr−1, while Dumont d'Urville located very near the magnetic pole showed a drop of ∼50 nT yr−1 until 1994. A study of the observed F values over the past five decades at 23 observatories from the Antarctic and sub-Antarctic regions indicates that contours of yearly decrease in F follow a definite pattern, with maximum decrease lying in a belt encompassing Maitri. These observations are of importance in the light of modelling works at the Earth's Core–Mantle boundary pointing to two prominent regions of reverse magnetic flux (RMF) occurring beneath South America, South Africa and a large part of Antarctica, and which may merge sometime to cause reversal of the present geomagnetic field polarity. The importance of continuous monitoring of F at various locations in Antarctic and sub-Antarctic regions is brought out in this work. It is equally important to understand the cause behind this rapid decrease in F.

The most recent reports about the family Ammotheidae of pycnogonids from Southern Ocean waters are those of Munilla (2000, 2001, Scotia Sea), Pushkin (1993, various zones), Bamber (1995, Falkland Islands and South Shetland Islands) and Child (1994, various zones) who also provide historical background. Some species from Livingston Island and surrounding waters (South Shetland Islands, Drake Passage, Bransfield Strait) have been documented previously, mainly by Gordon (1932), Fry & Hedgpeth (1969), Pushkin (1993) and the papers of Child and Bamber mentioned above. Keys to this genus are given in Clark (1977) and Child (1994).

The shore environments of most sub-Antarctic islands have been described in a number of previous studies. However, there have been few attempts to quantify the variation in population and community patterns over different spatial scales. The objectives of this study were to provide an analysis of differences in the community structure of the biota of three exposed shore zones and of the macrofauna inhabiting holdfasts of the kelp Durvillaea antarctica across spatial scales of hundreds of metres, kilometres, and between a sheltered and exposed coast. Data were collected using a combination of quadrat, transect and direct sampling methods over the 1994–95 summer season. The results indicated that there were significant differences between coasts for some of the biotic variables in most of the habitats examined but that differences at the smaller spatial scales were more often significant. Thus, although wave exposure exerts an obvious effect on the shore biota of Macquarie Island, these effects are modified by other factors operating at smaller spatial scales. For the holdfast macrofauna, the overall patterns of community structure are likely to be due to the differential response of the component taxa to variation in holdfast volume and holdfast sediment content as well as other, currently undetermined factors.

Small to medium sized icebergs (200 m to 10 km across) in two areas of the Weddell Sea were tracked using satellite-borne Synthetic Aperture Radar (SAR) from 22 January–21 February 1994 and 29 January–25 February 1992 respectively. The westward mass flux of icebergs in the Antarctic Coastal Current was estimated at the eastern entrance to the Weddell Sea as being 50–70 Gta−1. A large contrast was found between observations over the narrow shelf here and the off-shelf area. The latter region had very much reduced iceberg density, and the bergs moved with slower and less coherent velocities compared with the fast, but narrow (10–20 km wide) flow in the Coastal Current. This region is a promising site for the monitoring of decadal trends in iceberg fluxes. The second study area in the south-western Weddell Sea showed iceberg motion consistent with non-contemporaneous observations of tagged icebergs, with steady flow parallel to the shelf-ice edge, at significantly lower densities and speeds than in the Coastal Current but almost double that observed off-shelf in the eastern Weddell Sea. We also suggest that shipboard observations of icebergs need careful analysis to avoid their over-estimating true iceberg concentrations by a substantial amount.

Macrofossils discovered in the Battye Glacier Formation (Pagodroma Group) of the Prince Charles Mountains, East Antarctica, provide important insight into marine life of the mid-Tertiary, rarely preserved elsewhere on the continent. Recorded are five species of macroinvertebrates; these are Adamussium n. sp.? cf. colbecki (Smith, 1902) (Bivalvia), Laternula? sp. (Laternulidae), Mytilidae genus and species indeterminate (Bivalvia), Bivalvia genus and species indeterminate, and Polychaeta genus and species indeterminate. Based on stratigraphical data and faunal composition, the clasts are dated as no younger than Early Miocene. This is one of the oldest reports of Adamussium from Antarctica, previously known from the Late Pliocene to Recent with a possible record in the Late Oligocene–Early Miocene. Palaeoecological data and facies analysis indicate that these taxa inhabited a shallow- to mid-shelf marine environment of normal salinity that was oligotrophic. The substrate was a soft, pebbly and sandy bottom that was sufficiently mobile to sponsor deep burrowing forms.

The Patuxent Range forms the most southerly third of the Pensacola Mountains, East Antarctica. Largely unstudied since the original geological survey work of the 1960s, the Patuxent Range was thought to expose metasediments deformed by a single Precambrian event. However, new structural data collected from two geographically separate areas in the central Patuxent Range reveal the presence of three distinct generations of structures. A synthesis of the regional geology together with new data suggests that the Patuxent Formation was mildly deformed during end Cambrian times as part of the late stage Ross Orogeny. However, the most intense deformation, although poorly constrained in age, probably occurred during the Permo-Triassic Gondwanian Orogeny. A third phase of deformation predates the intrusion of 183 Ma lamprophyre dykes and involved an inferred vertical axis rotation of the pre-existing D1 and D2 structures and the localized development of a spaced foliation and mesoscale folding. These D3 structures may be the first evidence of an Early Jurassic deformation event in the Transantarctic Mountains, which correlates with the Peninsula and Rangitata I orogenies of the Antarctic Peninsula and New Zealand, respectively.

Analyses on a sediment core collected from the Windmill Islands, East Antarctica are used to demonstrate that climatic conditions in this region prior to the Last Glacial Maximum were similar to those during the Holocene and that the area was overrun by ice at some stage between 26 kyr BP and the onset of biogenic sedimentation 11 kyr BP. The 10.9 m long core was taken from a marine inlet (epishelf lake) on Peterson Island and is predominantly a sapropel of Holocene age. Material in the lower part of the core includes a till layer lain down during the last glacial in the region and below this till is material which has been dated to 26 kyr BP. Geochemical analyses conducted on the core demonstrate similarities between the Holocene sequence and the preglacial material. The Holocene sequence shows enhanced biogenic production and periods of open water around 4 kyr BP, suggesting a climatic optimum around that time. A subsequent decline in conditions, probably a colder climate with greater extent of sea ice, is evident from 1 kyr BP to the present. The data support results from ice core studies on nearby Law Dome, which suggest there was a period of warming around 11.5 to 9 kyr BP, that recent summer temperatures are low relative to a few centuries ago, and that increasing winter temperatures are the main contributing factor to a recent overall warming in the region.