Temperatures within soil and plant habitats on Signy Island in the maritime Antarctic were measured during 1987. Four sites were monitored using minithermistors attached to a data logging system. Three main periods within the annual temperature cycle were identified. In spring/summer (November–March) there was much inter-day variation in maximum temperatures, but minimum daily temperatures were always close to 0°C. However, there were very few freeze-thaw cycles extending below the −0.5°C threshold during this period, and those that occurred were not severe. It is considered that freeze-thaw cycling is unlikely to be a significant factor in organism survival during summer. All sites showed a long period of relatively mild subzero temperatures during autumn (March–May). This may be of importance in promoting cold-hardiness of organisms living in these ecosystems before the decline to lower winter temperatures. Minimum winter temperatures varied markedly between sites; lowest temperatures occurring in areas where there was little insulating snow cover. Within site temperature variation was generally small, confirming the validity of the use of small numbers of probes to monitor environmental temperatures in such habitats.

South Africa is currently proclaiming a Marine Protected Area (MPA) in the Exclusive Economic Zone (EEZ) of its sub-Antarctic Prince Edward Islands. The objectives of the MPA are to: 1) contribute to a national and global representative system of MPAs, 2) serve as a scientific reference point to inform future management, 3) contribute to the recovery of the Patagonian toothfish (Dissostichus eleginoides), and 4) reduce the bird bycatch of the toothfish fishery, particularly of albatrosses and petrels. This study employs systematic conservation planning methods to delineate a MPA within the EEZ that will conserve biodiversity patterns and processes within sensible management boundaries, while minimizing conflict with the legal toothfish fishery. After collating all available distributional data on species, benthic habitats and ecosystem processes, we used C-Plan software to delineate a MPA with three management zones: four IUCN Category Ia reserves (13% of EEZ); two Conservation Zones (21% of EEZ); and three Category IV reserves (remainder of EEZ). Compromises between conservation target achievement and the area required by the MPA are apparent in the final reserve design. The proposed MPA boundaries are expected to change over time as new data become available and as impacts of climate change become more evident.

A common precursor to ice shelf disintegration, most notably that of Larsen B Ice Shelf, is unusually intense or prolonged surface melt and the presence of surface standing water. However, there has been little research into detailed patterns of melt on ice shelves or the nature of summer melt ponds. We investigated surface melt on Larsen C Ice Shelf at high resolution using Envisat advanced synthetic aperture radar (ASAR) data and explored melt ponds in a range of satellite images. The improved spatial resolution of SAR over alternative approaches revealed anomalously long melt duration in western inlets. Meteorological modelling explained this pattern by föhn winds which were common in this region. Melt ponds are difficult to detect using optical imagery because cloud-free conditions are rare in this region and ponds quickly freeze over, but can be monitored using SAR in all weather conditions. Melt ponds up to tens of kilometres in length were common in Cabinet Inlet, where melt duration was most prolonged. The pattern of melt explains the previously observed distribution of ice shelf densification, which in parts had reached levels that preceded the collapse of Larsen B Ice Shelf, suggesting a potential role for föhn winds in promoting unstable conditions on ice shelves.

Glaciers on the Antarctic Peninsula have recently shown changes in extent, velocity and thickness, yet there is little quantification of change in the mass balance of individual glaciers or the processes controlling changes in extent. Here a high-resolution digital elevation model and a semi-automated drainage basin delineation method have been used to define glacier systems between 63°S–70°S on the mainland and surrounding islands, resulting in an inventory of 1590 glacier basins. Of these, 860 are marine-terminating glaciers whose ice fronts can be defined at specific epochs since the 1940s. These ice front positions were digitized up to 2010 and the areas for all individual glacier basins were calculated. Glaciological characteristics, such as geometry, slope and altitudes, were attributed to each glacier, thus providing a new resource for glacier morphological analyses. Our results indicate that 90% of the 860 glaciers have reduced in area since the earliest recorded date. A north–south gradient of increasing ice loss is clear, as is distinct behaviour on the east and west coasts. The area lost varies considerably between glacier types, with correlations apparent with glacier shape, slope and frontal-type. Temporal trends indicate a uniform retreat since the 1970s, with a period of small re-advance in the late 1990s.

Aliphatic (AHs) and polycyclic aromatic hydrocarbons (PAHs) concentrations were measured in marine surface sediments around the Brazilian station in Admiralty Bay, during the summers of 1997/98 and 1999/2000 using GC-FID and GC-MS. Total aliphatic hydrocarbons ranged from 0.15 to 13.28 μg·g−1 (dry weight) while n-alkanes varied between 0.10 and 9.63 μg·g−1. The highest concentrations were obtained at the sewage outfall, with decreasing levels away from the outfall. The distribution of n-alkanes showed significant quantities of long chain n-alkanes (n-C22 to n-C34) at sites near the Brazilian station that may be attributed to the station activities. A short chain n-alkanes sequence (n-C12 to n-C21) associated with diesel fuel arctic (DFA) was present in all the samples. Total PAHs varied from 9.45 to 270.5 ng·g−1. The higher PAHs level and the presence of an unresolved complex mixture only in sediment from the sewage outfall is an indication of oil contamination at this location. A slight increase in PAHs near the Brazilian station since 1993 may be attributed to an increase in the number of staff over recent years. In general, the concentration of AHs and PAHs was similar to that found in other Antarctic areas.

Thirty eight strains of Antarctic bacteria were screened for the ability to produce polyunsaturated fatty acids (PUFA). Five strains contained eicosapentaenoic acid (20:5ω3) in the range of trace to 3.3% of total fatty acids, and up to 1.4 mg g-1 dry weight. Thirteen strains produced polyunsaturates including 18:2ω6, 18:3ω3, 18:4ω3 and 20:4ω6 in the range of trace to 7.0% of total fatty acids. Although the data set is currently small, the proportion of Antarctic strains found to produce PUFA's is higher than that found for temperate marine bacteria (and is similar to that recorded for barophilic bacteria). This suggests that the Antarctic environment has naturally selected for bacterial strains capable of maintaining membrane lipid fluidity by the production of PUFA. These results highlight the potential of Antarctic bacteria for possible consideration in the industrial production of PUFA. These results highlight the potential of Antarctic bacteria for possible consideration in the industrial production of PUFA. The fatty acid composition of Flectobacillus glomeratus is reported and discussed in relation to other closely related Antarctic flavobacteria. Fatty acid composition is also shown to represent an important chemotaxonomic tool to aid with the identification of Antarctic bacteria.

The early climate of Mars (Noachian Period, the first ~20% of its history) is thought to differ significantly from that of its more recent history (Amazonian Period, the last ~66%) which is characterized by hyperarid, hypothermal conditions that result in mean annual air temperatures (MAAT) well below 0°C, a global cryosphere, minimal melting on the ground surface, and a horizontally stratified hydrologic system. We explore the nature of the fluvial and lacustrine environments in the Mars-like hyperarid, hypothermal McMurdo Dry Valleys (MDV), where the MAAT is well below 0°C (~ -14 to -30°C) in order to assess whether the Late Noachian geologic record can be explained by a climate characterized by “cold and icy” conditions. We find that the MDV hydrological system and cycle provide important insights into the potential configuration of a “cold and icy” early Mars climate in which MDV-like ephemeral streams and rivers, and both closed-basin and open-basin lakes could form. We review a series of MDV fluvial and lacustrine features to guide investigators in the analysis of the geomorphology of early Mars and we outline a new model for the nature and evolution of a “cold and icy” Late Noachian climate based on these observations. We conclude that a cold and icy Late Noachian Mars with MAAT below freezing, but peak seasonal and peak daily temperatures above 0°C, could plausibly account for the array of Noachian-aged fluvial and lacustrine features observed on Mars. Our assessment also provides insight into the potential effects of punctuated warming on a cold and icy early Mars, in which impact crater formation or massive volcanic eruptions cause temperatures in the melting range for decadal to centennial timescales. We outline a set of outstanding questions and tests concerning the nature and evolution of these features on Mars.

Quartz stone sublithic cyanobacterial communities are common throughout the Vestfold Hills, Eastern Antarctica (68°S 78°E) contributing biomass in areas otherwise devoid of any type of vegetation. In this study, the sublithic microbial community and underlying soil was investigated using a variety of traditional and molecular methods. Although direct epifluorescent counts of the sublithic growth (average 1.1 × 109 cells g−1 dry weight) and underlying soil (0.5 × 109 cells g−1 dry weight) were similar, sublith viable counts (2.1 × 107 cfu g−1 dry weight) were on average 3-orders of magnitude higher in the subliths. Enrichment and molecular analyses revealed the predominate cyanobacteria were non-halophilic, able to grow optimally at 15–20°C, and were related to the Phormidium subgroup with several distinct morphotypes and phylotypes present. Sublithic heterotrophic bacterial populations and those of underlying soils included mostly psychrotolerant taxa typical of Antarctic soil. However, psychrophilic and halophilic bacteria, mostly members of the alpha subdivision of the Proteobacteria and the order Cytophagales, were abundant in the sublithic growth film (20–40% of the viable count and about 50% of isolated individual taxa) but absent from underlying soils. It is suggested that quartz stone subliths might constitute a “refuge” for psychrophilic bacteria.

Year-round temperature measurements at 1600 m elevation during 1994 in the Asgard Range Antarctica, indicate that the mean annual frost point of the ice-cemented ground, 25 cm below the surface, is −21.7 ± 0.2°C and the mean annual frost point of the atmosphere is −27.5 ± 1.0°C. The corresponding mean annual temperatures are −24.9°C and −23.3°C. These results imply that there is a net flux of water vapour from the ice to the atmosphere resulting in a recession of the ice-cemented ground by about 0.4–0.6 mm yr1. The level of the ice-cemented permafrost is about 12 cm below the level of dry permafrost. The summer air temperatures would have to increase about 7°C for thawing temperatures to just reach the top of the subsurface ice. Either subsurface ice at this location is evaporating over time or there are sporadic processes that recharge the ice and maintain equilibrium over long timescales.

In an attempt to clarify the release of trace elements from the seasonal coastal sea ice, samples were periodically collected in a nearshore station inside the Gerlache Inlet (Terra Nova Bay, Western Ross Sea), during the summer 2000/01 and analysed for dissolved and particulate cadmium, copper, iron, manganese and lead, as well as salinity, suspended particulate matter, nutrients and phytoplankton pigments. In order to provide insight on the metal association with the particles included in the sea ice, the metal solid speciation was also investigated. Both vertical distributions within the ice cores and temporal variations at the seawater interface were studied, in an effort to fully characterize the system and correlation among the considered parameters. Concentrations and speciation patterns clearly indicate metal incorporation within the annual sea ice due to resuspension of sediments, followed by release of particulate metals during melting as a primary process affecting trace metal availability in the Antarctic coastal waters.

Fifty four surface sediment samples from the western and central Ross Sea were examined to determine relationships between modern oceanographic conditions and surface sediment diatom assemblages. A centered R mode principal components analysis demonstrates four geographically distinct assemblages. The assemblage just north of the Ross Ice Shelf in the central Ross Sea is most closely associated with Stephanopyxis spp. (a heavily silicified diatom abundant during the Pliocene), and may result from a combination of winnowing/reworking, and modern flux of primarily non-siliceous algae. The algal assemblage in the western part of the central Ross Sea is most closely associated with Thalassiosira gracilis (an open water diatom), and reflects early seasonal pack ice break up during the late spring inception of the Ross Sea polynya. The algal assemblage north of Drygalski Ice Tongue, in the western Ross Sea, is most closely associated with Fragilariopsis curta (a diatom common in stratified ice edge zones), suggesting that water column seeding by species melting out of coastal sea ice is important in this area. The assemblage south of Drygalski Ice Tongue is most closely associated with resting spores of Thalassiosira antarctica (a diatom associated with coastal waters). Although the habitat of T. antarctica requires future research, we speculate that sea ice conditions unique to area B support an autumnal T. antarctica bloom.

Community analyses of the macrobenthos living on the Weddell Sea shelf revealed a distinct horizontal patchiness. Within some systematic groups a specific faunistic classification could clearly be defined, e.g. for asterozoans and holothurians. Whilst for fish, only a general zoogeographical pattern was discernible, there were some recognisable relationships to different microhabitats. The extreme differences in the distribution of sponges observed seems to reflect their highly variable biological characteristics. Studies using underwater imaging methods for benthic research have provided strong evidence for the ecological significance of two factors. The first, iceberg scouring, leads to a variety of simultaneous stages of recolonization, which result in an increase in beta-diversity. As a consequence, it is unlikely that regionally a stage approaching a theoretical climax will ever be attained. Secondly, the structural diversity of living substrata provides the basis for an additional variety of epibiotic species. Only weak or non-detectable correlations have been found between benthic assemblages and physical parameters, such as water depth, sediment type, bathymetric features and the abundance of deposited phytodetritus. This indicates a benthic system which is relatively uncoupled from processes in the water column. The combination of stable environmental conditions and disturbances taking place over long periods of time, which are partly a special feature of Antarctica's glacial history, shaped the diversity and faunal composition of the macrobenthos. Consequently, neither Houston's “intermediate-disturbance-hypothesis” nor Sander's “stability-time-hypothesis” can be rejected for this part of the Antarctic ecosystem.

Stable isotope data from waters of lakes in the McMurdo Dry Valleys (MDV) of southern Victoria Land, Antarctica are presented in order to establish the climatic history of this region over the past two millennia. New data from Lake Fryxell and Lake Hoare in Toylor Valley, along with previously published data from Lake Vanda, Wright Valley and Lake Bonney, Taylor Valley are used to infer the recent climatic history of MDV. Lakes Vanda, Fryxell and Bonney appear to have lost their ice covers and evaporated to small, hypersaline ponds by 1000 to ~1200 yr BP. Lake Hoare either desiccated or did not exist prior to 1200 yr BP. These data indicate a major lowering of lake level prior to ~1000 yr BP, followed by a warmer and/or more humid climate since then.

Antarctica is a continental island and the waters of its shelf and upper slope are an insular evolutionary site. The shelf waters resemble a closed basin in the Southern Ocean, separated from other continents by distance, current patterns and subzero temperatures. The benthic fish fauna of the shelf and upper slope of the Antarctic Region includes 213 species with higher taxonomic diversity confined to 18 families. Ninety-six notothenioids, 67 liparids and 23 zoarcids comprise 45%, 32% and 11% of the fauna, a combined total of 88%. In high latitude (71–78°S) shelf areas notothenioids dominate abundance and biomass at levels of 90–95%. Notothenioids are also morphologically and ecologically diverse. Although they lack a swim bladder, the hallmark of the notothenioid radiation has been repeated diversification into water column habitats. There are pelagic, semipelagic, cryopelagic and epibenthic species. Notothenioids exhibit the disproportionate speciosity and high endemism characteristic of fish species flock. Antifreeze glycopeptides originating from a transformed trypsinogen gene are a key innovation. It is not known when the modern Antarctic shelf fauna assumed its current taxonomic composition. A late Eocene fossil fauna was taxonomically diverse and cosmopolitan. There was a subsequent faunal replacement with little carryover of families into the modern fauna. Basal notothenioid clades probably diverged in Gondwanan shelf locations during the early Tertiary. Dates inferred from molecular sequences suggest that phyletically derived Antarctic clades arose 15–5 m.y.a.

Marine sediment cores were obtained from in front of the Müller Ice Shelf in Lallemand Fjord, Antarctic Peninsula in the austral summer of 1990–91. Sedimentological and geochemical data from these cores document a warm period that preceded the advance of the Müller Ice Shelf into Lallemand Fjord. The advance of the ice shelf is inferred from a reduction in the total organic carbon content and an increase in well-sorted, aeolian, sand in cores proximal to the present calving line. This sedimentological change is paralleled by a change in the foraminiferal assemblages within the cores. Advance of the ice shelf is indicated by a shift from assemblages dominated by calcareous benthic and planktonic forms to those dominated by agglutinated forms. A 14C chronology for the cores indicates that the advance of the Müller Ice Shelf took place c. 400 years ago, coincident with glacier advances in other high southern latitude sites during the onset of the Little Ice Age. Ice core evidence, however, documents this period as one of warmer temperatures for the Antarctic Peninsula. We suggest that the ice shelf advance was linked to the exclusion of circumpolar deep water from the fjord. This contributed to increased mass balance of the ice shelf system by preventing the rapid undermelt that is today associated with warm circumpolar deep water within the fjord. We also document the recent retreat of the calving line of the Müller Ice Shelf that is apparently in response to a recent (four decade long) warming trend along the western side of the Antarctic Peninsula.

The demersal fish fauna of the southern and eastern Weddell Sea is described. The following species were recorded for the first time in this area: Aethotaxis mitopteryx, Bathyraja eatoni, B. Maccaini, B. sp2 (FAO-list), Bathydraco marri, Dissostichus mawsoni, Macrourus holotrachys, Muraenolepis sp., Notothenia coriiceps, Notothenia kempi, Psilodraco spec. and Trematomus nicolai. In terms of biomass the dominant species on the very narrow eastern continental shelf were Chionodraco myersi (49%), Trematomus eulepidotus (11%), C. hamatus (7%), T. lepidorhinus (6%), Pagetopsis maculatus (5%) and T. scotti, Cryodraco antarcticus, Cygnodraco mawsoni and Pleuragramma antarcticum (4% each). The highest density of individuals and greatest biomass was found between 400 and 650 m water depth. Here, C. myersi, T. eulepidotus and T. lepidorhinus dominated the catches. The shallow shelf area was inhabited by smaller species such as T. scotti, T. centronotus, P. maculatus, Artedidraco skottsbergii, A. shackletoni, and Prionodraco evansii. In the southern Weddell Sea Akarotaxis nudiceps, Dolloidraco longedorsalis, Gerlachea australis, Pleuragramma antarcticum, and Trematomus loennbergi were dominant. Members of the Channichthyidae occurred only occasionally, most of these are Dacodraco hunteri. The biomass of the demersal fish fauna was estimated to be 0.3 to 1.6 t km−2 on the Vestkapp shelf and 0.1 to 0.4 t km−2 for Gould Bay. Biomass values greater than 1.0 t km−2 were found at the shelf edge.

This review assesses the circumpolar occurrence of emerged marine macrofossils and sediments from Antarctic coastal areas in relation to Late Quaternary climate changes. Radiocarbon ages of the macrofossils, which are interpreted in view of the complexities of the Antarctic marine radiocarbon reservoir and resolution of this dating technique, show a bimodal distribution. The data indicate that marine species inhabited coastal environments from at least 35 000 to 20 000 yr BP, during Marine Isotope Stage 3 when extensive iceberg calving created a ‘meltwater lid’ over the Southern Ocean. The general absence of these marine species from 20 000 to 8500 yr BP coincides with the subsequent advance of the Antarctic ice sheets during the Last Glacial Maximum. Synchronous re-appearance of the Antarctic marine fossils in emerged beaches around the continent, all of which have Holocene marine-limit elevations an order of magnitude lower than those in the Arctic, reflect minimal isostatic rebound as relative sea-level rise decelerated. Antarctic coastal marine habitat changes around the continent also coincided with increasing sea-ice extent and outlet glacial advances during the mid-Holocene. In view of the diverse environmental changes that occurred around the Earth during this period, it is suggested that Antarctic coastal areas were responding to a mid-Holocene climatic shift associated with the hydrological cycle. This synthesis of Late Quaternary emerged marine deposits demonstrates the application of evaluating circum-Antarctic phenomena from the glacial-terrestrial-marine transition zone.

The diet of mainly adult and sub-adult male Antarctic fur seals (Arctocephalus gazella) was investigated during the austral winters of 1992 and 1993 using faecal (scat) analysis. Of samples containing identifiable prey remains (n = 376), c. 28% contained krill alone, c. 37% contained fish alone and c. 35% contained both krill and fish. The mean size of krill taken was smaller than in summer due to the absence of large adult krill of 55–60 mm total length. Of the 25 fish taxa taken, krill-feeding species predominated, especially in scats that also contained krill. Non-krill feeding species were more abundant in scats containing fish alone. The mackerel icefish (Champsocephalus gunnari Lönnberg 1905), which feeds mainly on krill, was the most important fish species in terms of absolute frequency (53%), frequency of occurrence (69%) and estimated biomass (47%); fur seals may have a significant impact on local stocks of this species. Cephalopods and pelagic fish (myctophids) were of minor importance in the diet (<2%). The importance of krill and krill-feeding fish species suggests that the male fur seals, which are present around South Georgia in winter, are targeting their foraging on a krill and fish community, probably associated with krill aggregations.

On the continental rise west of the Antarctic Peninsula there are nine large mounds interpreted as sediment drifts, separated by turbidity current channels. Drift 7 is 150 km long, 70 km wide and up to 700 m high and is asymmetric, with steep sides on the south-east (towards the continent) and south-west, and gentle slopes to north-west and north-east. Cores on the gentle sides of the drift show a cyclicity between brown, bioturbated, diatom-bearing mud with foraminifera and radiolarians, and grey, laminated, barren mud. Biostratigraphic evidence is consistent with a Late Quatermary age. Detailed lithostratigraphy and magnetic susceptibility data allow precise correlation over distances of tens of kilometres. On the basis of chemostratigraphy, the brown sediment is interpreted as interglacial (isotope stages 1 and 5) and the grey as glacial (stages 2–4 and 6). Sedimentation rates are 3.0–5.5 cm ka-1. Cores on the steep sides of the drift recovered a condensed section with thinner cycles and hiatuses. Fine grain size, very poor sorting and the absence of a mode in the silt size range indicate deposition from suspension with only weak current activity. There is little evidence for cyclic changes in bottom current strength. Supply of sediment to the benthic nepheloid layer was by entrainment of mud from turbidity currents, and by setting of pelagic material (biogenic grains, IRD, sediment suspended in meltwater plumes). Cyclic changes in sediment supply include more biogenic supply in interglacials with less sea ice cover, more terrigenous supply from turbidites in glacials with ice sheets grounded to the shelf edge, and changes in IRD content

Springtime ozone depletion over Antarctica has been observed for over a decade. Associated with ozone depletion is an increase in the levels of biologically harmful ultraviolet-B (UV-B) that reach the earth's surface, a situation that has prompted much controversy about the ecological effects of this atmospheric phenomenon on Antarctic ecosystems. A major hindrance to assessing the ecological impact is lack of appropriate data on Antarctic systems before the present ozone depletion cycle began. In addition, certain physical features of the Antarctic environment (clouds, snow and ice) and the UV-B photobiology (repair processes and protective strategies) of endemic species can alter the potential biological effects of this environmental stress in, as yet, undetermined ways. Increases in incident UV levels will most likely result in changes in the taxonomic structure of communities. The effects of these changes on net productivity and trophic dynamics cannot be accurately assessed without quantifying ambient doeses of UV and characterizing the UV photobiology of individual species. Both the physical features of the springtime environment and the biological responses of endemic species must be considered in future research efforts to evaluate the biological consequences of the Antarctic ozone hole.