Three hydrocarbon-degrading Rhodococcus strains isolated from polluted Antarctic soils proved to be closely related despite their different origins. Strains had a similar hydrocarbon degradation pattern and optimum growth temperature ranged between 25ºC and 30ºC, showing that strains are psychrotolerant but not psychrophiles. Specific growth rate on rich media ranged between 0.12 and 0.21 h−1, higher than those observed on hydrocarbons as carbon source. Results suggest that in Antarctic contaminated soils, closely related Rhodococcus strains are present and could play an important role in decontamination. Microcosm systems showed that, although the natural microflora respond significantly to the pollutants, bioaugmentation with Rhodococcus strain (ADH), improved biodegradation either alone or mixed with a hydrocarbon-degrading Acinetobacter strain. In comparison with microcosm where only ADH was inoculated, a non-significant decrease in hydrocarbon concentration was observed when ADH was inoculated as mixed culture with a previously tested strain. Pollutants dramatically reduced bacterial groups in soils resulting in a dominance of Pseudomonas. Microcosms showed that when natural microflora has no previous history of exposure to the pollutants, bioaugmentation with autochthonous strains improves degradation of the contaminants. The positive response of the native bacteria to the pollutants leaves the question open as to whether bioaugmentation is necessary when soils have a long previous exposure to hydrocarbons.

The RV Nathaniel B. Palmer was used for bottom trawling at depths of 100–1200 m during two recent cruises in the south-western Ross Sea. Although only 10 of 20 trawls were completely successful, a diverse collection of 979 specimens was obtained representing 47 species (36 notothenioids and 11 nonnotothenioids) and eight families. The collection included four new species, a new colour morph of a known species and eight rare species. The collection also established four new locality records, three second occurrences, three most southerly records and eleven new depth records for fish in the Ross Sea. Good taxonomic coverage for some groups was indicated by collection of all four species of Artedidraco, nine of ten bathydraconids and seven of eight channichthyids occurring in East Antarctica. The most abundant species were Trematomus scotti (29.7%), Bathydraco marri (10.4%), Trematomus eulepidotus (8.7%) and Dolloidraco longedorsalis (6.1%). Fish biomass was determined at two stations. The fish fauna of the Ross Sea south of the 1000-m isobath includes at least 80 species – 54 notothenioids and 26 non-notothenioids, approximately the same number as the Weddell Sea. Species diversity (H′ = 1.88) was higher than both the Weddell Sea and boreal regions. This collection indicates that, even in relatively shallow water, knowledge of specific and intraspecific diversity in the Ross Sea fauna is incomplete.

The first fossils from Antarctica were collected from Seymour Island in December 1892, during the voyage of the Jason under Captain C.A. Larsen. The Swedish South Polar Expedition of 1901–1903, led by Otto Nordenskjöld, proved that there were extensive deposits of fossiliferous Cretaceous and Tertiary sedimentary rock in the James Ross Island area. This was confirmed by later geological mapping (Bibby 1966). Subsequent investigations have led to the establishment of various lithostratigraphic schemes (e.g. Ineson et al. 1986), and interpretation of the sedimentary history in terms of basin evolution (Elliot 1988, Macdonald et al. 1988). Unfortunately, different names have been proposed for the depositional basin, with consequent confusion. The purpose of this note is to review previous usage and propose a new consistent nomenclature for the sedimentary basins east of the Antarctic Peninsula.

Ecosystem services are the benefits that mankind obtains from natural ecosystems. Here we identify the key services provided by the Southern Ocean. These include provisioning of fishery products, nutrient cycling, climate regulation and the maintenance of biodiversity, with associated cultural and aesthetic benefits. Potential catch limits for Antarctic krill (Euphausia superba Dana) alone are equivalent to 11% of current global marine fisheries landings. We also examine the extent to which decision-making within the Antarctic Treaty System (ATS) considers trade-offs between ecosystem services, using the management of the Antarctic krill fishery as a case study. Management of this fishery considers a three-way trade-off between fisheries performance, the status of the krill stock and that of predator populations. However, there is a paucity of information on how well these components represent other ecosystem services that might be degraded as a result of fishing. There is also a lack of information on how beneficiaries value these ecosystem services. A formal ecosystem assessment would help to address these knowledge gaps. It could also help to harmonize decision-making across the ATS and promote global recognition of Southern Ocean ecosystem services by providing a standard inventory of the relevant ecosystem services and their value to beneficiaries.

As part of the multi-disciplinary project, Antarctic Marine Ecosystem Research at the Ice Edge Zone (AMERIEZ), habitat selection by marine mammals was investigated within the marginal ice zone in relation to measured ice variables and other environmental factors. Data were collected on three cruises to the southern Scotia and northern Weddell seas during spring 1983, autumn 1986, and winter 1988. During winter, Antarctic fur seals were significantly associated with drift, pancake, brash ice, icebergs, and areas of uneven floe distribution, all characteristic of the marginal ice zone. Fur seals were seen in open water close to the ice edge during autumn, but during spring, as the pack ice began to retreat rapidly, animals were seen more often away from the ice. Minke whales were also associated with pancake and new ice but were seen further into the pack ice during both winter and autumn. The largest groups of minke whales during winter were observed with a large krill swarm in new ice. Crabeater seal was exclusively a species of the deep pack ice during all seasons and was associated with ice cover of 7–8 oktas and evenly distributed ice floes.

The total annual food consumption of the seabird and seal community breeding at lles Kerguelen was estimated to be 1.8×106 t in 1985. This biomass included c. 0.99×106 t (55%) of crustaceans, 0.46×106 t (26%) of myctophid fish, 0.07×106 t (4%) of other fish species, and 0.26×106 t (15%) of squid. During the same year, the mass of prey consumed in Crozet waters was previouly estimated to be 3.1×106 t, the total food consumption in the Indian Ocean area including the two archipelagos thus totalling c. 5×106 t in 1985. Four species of top predators, the king penguin, macaroni penguin, elephant seal, and fur seal, consumed 59% and 56% of the amount of prey eaten in 1985 by the whole community at Kerguelen and Crozet islands, respectively. Between 1962 and 1985, population changes of these four species induced 18 and 41% increases in their food consumption at Kerguelen and Crozet islands. Population changes included a moderate increase in the number of macaroni penguins and a marked rise of king penguin populations. Assuming that the diet of king penguin was similar in 1962 and 1985, its population increase will have required a concomitant increase of 0.6×106 t in the consumption of myctophid fish in Crozet and Kerguelen waters.

Weaned pups and post-moult female elephant seals (Mirounga leonina) were fitted with satellite transmitters at King George Island (South Shetland Islands) between December 1996 and February 1997. Of the nine adult females tracked for more than two months, three stayed in a localized area between the South Shetland Islands and the South Orkney Islands. The other six females travelled south-west along the coast of the Antarctic Peninsula up to the Bellingshausen Sea. Two of them then moved north-east and hauled out on South Georgia in October. One female was last located north of the South Shetland Islands in March 1998. In total, eight females were again sighted on King George Island and six of the transmitters removed. The tracks of the weaners contrasted with those of the adults. In January, five juveniles left King George Island for the Pacific sector spending about four weeks in the open sea west of the De Gerlache Seamounts. Three of them returned to the tip of the Antarctic Peninsula in June, of which one was last located on the Patagonian Shelf in November 1997. The juveniles avoided sea ice while the adults did not. The latter displayed behavioural differences in using the pack ice habitat during winter. Some females adjusted their movement patterns to the pulsating sea ice fringe in distant foraging areas while others ranged in closed pack ice of up to 100%. The feeding grounds of adult female elephant seals are more closely associated with the pack ice zone than previously assumed. The significance of the midwater fish Pleuragramma antarcticum as a potential food resource is discussed.

Determining the mass balance of the Greenland and Antarctic ice sheets (GIS and AIS) has long been a major challenge for polar science. But until recent advances in measurement technology, the uncertainty in ice sheet mass balance estimates was greater than any net contribution to sea level change. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (AR4) was able, for the first time, to conclude that, taken together, the GIS and AIS have probably been contributing to sea level rise over the period 1993–2003 at an average rate estimated at 0.4 mm yr-1. Since the cut-off date for work included in AR4, a number of further studies of the mass balance of GIS and AIS have been made using satellite altimetry, satellite gravity measurements and estimates of mass influx and discharge using a variety of techniques. Overall, these studies reinforce the conclusion that the ice sheets are contributing to present sea level rise, and suggest that the rate of loss from GIS has recently increased. The largest unknown in the projections of sea level rise over the next century is the potential for rapid dynamic collapse of ice sheets.

Hyper-arid deserts present extreme challenges to life. The environmental buffering provided by quartz and other translucent rocks allows hypolithic microbial communities to develop on sub-soil surfaces of such rocks. These refuge communities have been reported, for many locations worldwide, to be predominantly cyanobacterial in nature. Here we report the discovery in Antarctica’s hyper-arid McMurdo Dry Valleys of three clearly distinguishable types of hypolithic community. Based on gross colonization morphology and identification of dominant taxa, we have classified hypolithic communities as Type I (cyanobacterial dominated), Type II (fungal dominated) and Type III (moss dominated). This discovery supports a growing awareness of the high biocomplexity in Antarctic deserts, emphasizes the possible importance of cryptic microbial communities in nutrient cycling and provides evidence for possible successional community processes within a cold arid landscape.

We applied a modified version of the Miami isopycnic coordinate ocean general circulation model (MICOM) to the ocean cavity beneath the Ross Ice Shelf to investigate the circulation of ocean waters in the sub-ice shelf cavity, along with the melting and freezing regimes at the base of the ice shelf. Model passive tracers are utilized to highlight the pathways of waters entering and exiting the cavity, and output is compared with data taken in the cavity and along the ice shelf front. High Salinity Shelf Water on the western Ross Sea continental shelf flows into the cavity along the sea floor and is transformed into Ice Shelf Water upon contact with the ice shelf base. Ice Shelf Water flows out of the cavity mainly around 180°, but also further east and on the western side of McMurdo Sound, as observed. Active ventilation of the region near the ice shelf front is forced by seasonal variations in the density structure of the water column to the north, driving rapid melting. Circulation in the more isolated interior is weaker, leading to melting at deeper ice and refreezing beneath shallower ice. Net melting over the whole ice shelf base is lower than other estimates, but is likely to increase as additional forcings are added to the model.

Meteorological measurements performed during the austral summer of 1990–91 are used to evaluate the surface energy balance and ablation at an elevation of 100 m asl on the Ecology Glacier, which is an outlet glacier of the main ice cap of King George Island, Antarctica. Strong, gusty westerly winds prevail, although occasional south-easterly winds from the Weddell Sea reach the island. Generally, the climate can be characterized as relatively warm and humid with mean summer temperatures well above 0°C. As a result, considerable ablation (0.75 m water equivalent per month) takes place in the lower parts of the Ecology Glacier. The surface energy balance and ablation are calculated using a model with input from meteorological data. In spite of the large amount of cloud (0.83), solar radiation provided most of the energy used for melting (70.3 W m−2). The longwave radiation, sensible heat flux and latent heat flux contributed −9.5, 27.4 and 7.4 W m−2 respectively. Calculations show that a temperature rise of 1°C increases the ablation by almost 15%. This indicates that the ice caps and glaciers currently present on the subantarctic islands and the Antarctic Peninsula may be quite sensitive to climate change.

Despite their pivotal role as primary producers, there is little information as to the diversity and physiology of cyanobacteria in the meltwater ecosystems of polar regions. Thirty cyanobacterial mats from Adelaide Island, Antarctica were investigated using 16S rRNA gene pyrosequencing and automated ribosomal intergenic spacer analysis, and screened for cyanobacterial toxins using molecular and chemical approaches. A total of 274 operational taxonomic units (OTUs) were detected. The richness ranged between 8 and 33 cyanobacterial OTUs per sample, reflecting a high mat diversity. Leptolyngbya and Phormidium (c. 55% and 37% of the OTUs per mat) were dominant. Cyanobacterial community composition was similar between mats, particularly those obtained from closely adjacent locations. The cyanotoxin microcystin was detected in 26 of 27 mats (10–300 ng g-1 organic mass), while cylindrospermopsin, detected for the first time in Antarctica, was present in 21 of 30 mats (2–156 ng g-1 organic mass). The latter was confirmed via liquid chromatography-mass spectrometry and by the presence of the cyrAB and cyrJ genes. This study demonstrates the usefulness of pyrosequencing for characterizing diverse cyanobacterial communities, and confirms that cyanobacteria from extreme environments produce a similar range of cyanotoxins as their temperate counterparts.

Uncertainty exists over the importance of Antarctic toothfish (Dissostichus mawsoni) as prey of top predators in the Ross Sea. In this paper we assess relative weight given to direct, observational evidence of prey taken, as opposed to indirect evidence from scat and biochemical analysis, and conclude that toothfish are important to Weddell seals (Leptonychotes weddellii). The seals eat only the flesh of large toothfish and therefore they are not detected in scat or stomach samples; biochemical samples have been taken from seal sub-populations where toothfish seldom occur. Using direct observations of non-breeding seals away from breeding haulouts in McMurdo Sound, 0.8–1.3 toothfish were taken per day. Based on these and other data, the non-breeding portion of the McMurdo Sound seal population, during spring and summer, consume about 52 tonnes of toothfish. Too many unknowns exist to estimate the non-trivial amount consumed by breeders. We discuss why reduced toothfish availability to Weddell seals, for energetic reasons, cannot be compensated by a switch to silverfish (Pleuragramma antarcticum) or squid. The Ross Sea toothfish fishery should be reduced including greater spatial management, with monitoring of Weddell seal populations by CCAMLR. Otherwise, probable cascades will lead to dramatic changes in the populations of charismatic megafauna.

The Southern Ocean around Antarctica is no longer free from invasive marine species. The North Atlantic spider crab Hyas araneus (Linnaeus, 1758) (Crustacea: Decapoda: Majidae) has been recorded for the first time from the Antarctic Peninsula. Isolated for at least 25 million years, the endemic Antarctic Southern Ocean marine fauna is now being exposed to human-mediated influx of exotic species. Invasive species and polar warming combined can foster the probability of arrival and colonization by non-indigenous species, with unpredictable consequences for the Antarctic marine biota.

An Ekman analysis of the surface drainage winds over a sloping ice surface is reported. Ekman pumping by the boundary layer leads to the formation of an upper tropospheric cyclonic vortex above the summit of the ice sheet. The strength and distribution of upper level vorticity is determined by the shape of the underlying ice sheet. The calculation is verified by comparison with the results from a multi-level primitive equation model of flow above an axisymmetric ice sheet. Both models predict that the surface drainage flow will die out on a timescale of a few days, while the upper vortex is predicted to be considerably stronger than observed. Various mechanisms which could lead to the depletion of upper level vorticity, and hence to the retention of a substantial drainage flow, are discussed. It is concluded that disruption of the polar vortex by decaying mid-latitude cyclones, and the consequent export of cyclonic vorticity to lower latitudes, is the most probable mechanism.

This paper explores effects of environmental variability on the life cycle of the chokka squid, Loligo vulgaris reynaudii in South Africa, particularly the effect of physical and chemical influences on adult distribution, and the availability of spawning aggregations to the local jig fishery. The following hypotheses are presented: 1) temperature, dissolved oxygen and currents have a direct effect on the demersal distribution of adult chokka on the feeding grounds, but this is restricted to the west coast where environmental conditions are more extreme relative to the south coast, 2) chokka catches increase in proportion to the extent of coastal upwelling, 3) spawning behavior along the inshore regions (<50m) is strongly influenced by turbidity near the seabed. High turbidity forces the spawning popuation to lay their eggs in deeper waters, and are thus not available to the jig fishery. 4) El Niño – Southern Oscillation (ENSO) events are linked with large fluctuations in the availability of spawning squid aggregations to the inshore jig fishery.

Short and long-term exposure to elevated temperatures were studied in the Antarctic stenothermal protobranch bivalve Yoldia eightsi (Courthouy) from Potter Cove, King George Island (South Shetland Islands, Antarctica). Above a breakpoint temperature of 2°C – the upper habitat temperature for the Potter Cove Y. eightsi stock – both routine (RMR) and standard metabolic rate (SMR) increased steeply. The fraction of metabolism allocated to SMR, as well as the number of intervals of elevated activity per hour increased significantly with temperature. During acute exposure, ATP concentrations in the foot muscle peaked at 2°C and fell at 5°C, whereas superoxide dismutase (SOD) activity decreased upon warming. Slow stepwise warming to a final temperature of 11°C resulted in a significant decrease of SOD activity. Malondialdehyde concentration increased compared with controls at 0°C. In contrast to the effect of short-term exposure, tissue adenylate concentrations displayed a mild increase at higher temperatures during slow warming, indicating an acclimation response. A switch to anaerobic energy production could not be observed up to 11°C, demonstrating a higher level of thermal tolerance than in other Antarctic ectotherms, or a failure of the relevant pathways in Y. eightsi. The imbalance between pro- and antioxidant processes upon warming indicate oxidative stress to be one feature accompanying early heat stress in Y. eightsi.

Two species of lichens, six cyanobacteria, one diatom, 10 chlorophytes and two mycelial fungi were found at La Gorce Mountains (86°30′S, 147°W) at an altitude of about 1750 m. The lichens Lecidea cancriformis and Carbonea vorticosa occurred at a single site which is the most southerly record of lichens. Thousands of small ponds covered extensive ice-cored moraine. Nine ponds sampled had about 30 cm of ice overlying about 26 cm of water and contained algal mats dominated by Phormidium autumnale and cf. Leptolyngbya fragilis. The very low conductivity waters had high nitrate and low dissolved reactive phosphorus concentrations. Of 124 soil samples, five contained visible algae. In 32 there were only microscopic growths but no algae were detected in 87 samples, possibly because of lack of water for much of summer. A visible mat dominated by Hammatoidea normanni occurred in a rock fissure at the lichen site. At Price Bluff, green patches of Desmococcus cf.olivaceus, up to 20 cm2, were scattered over the moraine. Growths were revealed at the soil–ice interface when overlying soil up to one centimetre thick was removed. It is suggested that although dispersal of algae from local populations may be readily achieved establishment of populations is a rare event outside the pond environment.

We present two time series of bottom current and temperature collected 8 m above the seabed on either side of a large sediment drift located on the continental rise of the Pacific margin of the Antarctic Peninsula. The mean current speed is comparable (6.2 cm s−1 and 6.1 cm s−1 respectively), but the mean direction differs by about 121°. The direction of mean flow follows the bathymetric contour, and the maximum speed never exceeds 20 cm s−1 (below the typical benthic storm threshold). The potential temperature is remarkably stable (0.11 ± 0.01°C and 0.13 ± 0.02°C at the two sites). The cross-covariance indicates a significant peak at 20.2 days lag, slightly longer than the travel time of 18.7 days calculated between the two stations following the isobaths (98.4 km) and thus providing evidence for the topographic control on bottom water flow. The observed bottom water flow is consistent with deposition of Holocene hemipelagic sediments of the ‘drift maintenance’ stage. Indicators for palaeoceanographic conditions during glacial periods of the ‘drift maintenance’ stage and the older ‘drift growth’ stage are at present too scarce to understand fully how the past oceanographic conditions influenced the evolution of the drifts.

In Potter Cove, King George Island, Antarctica, macroalgae provide a significant food resource for herbivores. The demersal fish Notothenia coriiceps feeds on macroalgae. Eighteen algal species were identified in stomach contents: two chlorophytes, ten rhodophytes and six phaeophytes. Among these the rhodophyte Palmaria decipiens, the phaeophyte Desmarestia menziesii and the chlorophyte Monostroma hariotii comprised the greatest proportions of algal biomass. A food selection study showed four algae to be preferred (P. decipiens, M. hariotii, D. menziesii, Iridaea cordata) and two species to be avoided (Desmarestia anceps and Himantothallus grandifolius) by N. coriiceps. The present investigation indicates that this fish feeds not only intentionally, but also selectively, on macroalgae. Preference for particular algal species is not related to associated epifaunal biomass or to associated amphipod biomass.