Meltwater ponds are one of the most widespread aquatic habitats in ice-free areas of continental Antarctica. While most studies of such systems occur during the Antarctic summer, here we report on ice formation and water column attributes in four meltwater ponds on the McMurdo Ice Shelf during autumn, when they went from ice-free to > 80 cm thickness of ice. Ice thickness grew at an average rate of 1.5 cm d-1 in all ponds and as ice formed, salts and gases were excluded. This resulted in conductivity rising from 3–5 to > 60 mS cm-1 and contributed to the ebullition of gases. Incorporation of gas bubbles in the ice resulted in a high albedo and under-ice irradiance declined faster than incident, the former falling below 1 W m-2 (daily average) by early April. After two months of ice formation, only 0–15% of the volume of each pond was still liquid, although this represented 5–35% of the pond sediment area, where much of the biological activity was concentrated. We suggest that the stresses that the freezing process imposes may be as important to structuring the biotic communities as those during the more benign summer growth period.

Soil CO2 emission is an important part of the terrestrial carbon cycling and is influenced by several factors, such as type and distribution of vegetation. In this work we evaluated the spatial variability of soil CO2 emission in terrestrial ecosystems of maritime Antarctica, under two contrasting vegetation covers: 1) grass areas of Deschampsia antarctica Desv., and 2) moss carpets of Sanionia uncinata (Hedw.) Loeske. Highest mean emission was obtained for the Deschampsia (4.13 μmol m-2 s-1) developed on organic-rich soil with a strong penguin influence. The overall results indicate that soil temperature is not directly related to the spatial pattern of soil CO2 emission at the sites studied. Emission adjusted models were Gaussian and exponential with ranges varying from 1.3 to 2.8 m, depending on the studied site and vegetation cover.

Multivariate analysis shows that shells of Notodiscus sp. (Charopidae: Pulmonata) reported from South Georgia are smaller and proportionately taller than, but otherwise similar to, populations of Notodiscus hookeri (Reeve) from Iles Crozet and Iles Kerguelen. The origin of this solitary, and spatially limited, South Georgia population is enigmatic. It is confined to a remarkably small coastal lowland site which was glaciated at Last Glacial Maximum, precluding a Tertiary relict origin, and on the leeward north-east coast, ruling out post-glacial ocean rafting. The site is close to the King Edward Point settlement, yet the absence of any logistics connections with the Iles Crozet or Iles Kerguelen mitigates against anthropogenic introduction. The close proximity of the population to nests of blue-eyed shag (Phalacrocorax atriceps), Dominican gull (Larus dominicanus) and light-mantled sooty albatross (Phoebetria palpebrata) could imply the snail was originally introduced to South Georgia via these ocean transiting seabirds.

Globally, areas categorically known to be free of human visitation are rare, but still exist in Antarctica. Such areas may be among the most pristine locations remaining on Earth and, therefore, be valuable as baselines for future comparisons with localities impacted by human activities, and as sites preserved for scientific research using increasingly sophisticated future technologies. Nevertheless, unvisited areas are becoming increasingly rare as the human footprint expands in Antarctica. Therefore, an understanding of historical and contemporary levels of visitation at locations across Antarctica is essential to a) estimate likely cumulative environmental impact, b) identify regions that may have been impacted by non-native species introductions, and c) inform the future designation of protected areas under the Antarctic Treaty System. Currently, records of Antarctic tourist visits exist, but little detailed information is readily available on the spatial and temporal distribution of national governmental programme activities in Antarctica. Here we describe methods to fulfil this need. Using information within field reports and archive and science databases pertaining to the activities of the United Kingdom as an illustration, we describe the history and trends in its operational footprint in the Antarctic Peninsula since c. 1944. Based on this illustration, we suggest that these methodologies could be applied productively more generally.

In austral summer 2004 benthic macrofauna was sampled along a latitudinal gradient along the northern Victoria Land coast (Ross Sea). An Agassiz trawl was used for semi-quantitative data collection of macrozoobenthos at depths from 84 to 537 m. Multivariate analysis of abundance of higher taxonomic units discriminated between the four sample sites along the latitudinal gradient. A SIMPROF analysis emphasized these geographical clusters, as the samples showed no significant differences within each cluster. A change in community structure with depth was not observed. The dominant taxonomic groups along the Victoria Land coast were Echinodermata (39%), Arthropoda (24%), Polychaeta (14%), and Mollusca (12%), not accounting for colonial organisms. Thus, the overall structure of the benthic community off the Victoria Land coast is comparable to other Antarctic regions and shows a closer relationship to the eastern Weddell Sea shelf, which may be attributable to the extensive impact of grounded ice affecting both areas.

Cycling of deepwater silicon (Si) within the Southern Ocean, and its transport into other ocean basins, may be an important player in the uptake of atmospheric carbon, and global climate. Recent work has shown that the Si isotope (denoted by δ29Si or δ30Si) composition of deep sea sponges reflects the availability of dissolved Si during growth, and is a potential proxy for past deep and intermediate water silicic acid concentrations. As with any geochemical tool, it is essential to ensure analytical precision and accuracy, and consistency between methodologies and laboratories. Analytical bias may exist between laboratories, and sponge material may have matrix effects leading to offsets between samples and standards. Here, we report an interlaboratory evaluation of Si isotopes in Antarctic and sub-Antarctic sponges. We review independent methods for measuring Si isotopes in sponge spicules. Our results show that separate subsamples of non-homogenized sponges measured by three methods yield isotopic values within analytical error for over 80% of specimens. The relationship between δ29Si and δ30Si in sponges is consistent with kinetic fractionation during biomineralization. Sponge Si isotope analyses show potential as palaeoceaongraphic archives, and we suggest Southern Ocean sponge material would form a useful additional reference standard for future spicule analyses.

During January and February 2004, data on presence and distribution of killer whales (Orcinus orca) and other cetaceans were collected by helicopter surveys along the coastline of Terra Nova Bay and adjacent localities (western Ross Sea, Antarctica). A total of 37 sightings of killer whale, of both B and C types, were recorded as well as 17 sightings of Antarctic minke whales (Balaenoptera bonaerensis), nine of Balaenoptera spp., two of Arnoux’s beaked whale (Berardius arnuxii) and four of undetermined species. The type C killer whale was the most abundant, with 23 sightings, whereas we recorded type B only twice. Group size ranged between 1 and 30 animals, with an average of eight individuals. Seventeen killer whales were photo-identified and 13 resightings occurred during the study period. Killer whales showed a differential pattern in partitioning the study area. Their encounter rate was significantly higher (t-test = 2.6045, P < 0.05) in the northern area extending from Edmonson Point to the Campbell Glacier Tongue (encounter rate, ER = 0.031), compared to the southern area from Mario Zucchelli Station to the Drygalski Ice Tongue (ER = 0.003).

The order Tanaidacea includes over 1000 species which are mainly free-living or tube-dwelling detritivores. Exspina typica Lang, 1968 represents an exception to these common life styles, having being found in the intestine and body cavity of deep sea holothuroids. The 2008 New Zealand ‘IPY-CAML Cruise’ held in the Ross Sea collected several deepwater holothuroids that were observed to carry specimens of E. typica inside their coelomic cavity. A clear interpretation of this association was hence possible. Even if E. typica shows slight adaptations to a parasitic life style, the tanaids were found to actively ‘dig’ into the host's skin, grasping tissue with their claws and producing tunnels in the body wall. It is therefore possible to clearly define this association, which is here reported from the Antarctic for the first time, as parasitism.

Deception Island, an active stratovolcano located in the South Shetland Islands, Antarctica, provides excellent conditions for the thermophilic bacteria growth because of high ground temperatures in specific areas, such as Fumarole Bay where the temperatures are above the mesophilic range. Denaturing Gradient Gel Electrophoresis (DGGE) was used with the 16S ribosomal gene to analyse cultures of thermophilic bacteria from a soil sample taken from Fumarole Bay. Nine bands were sequenced and analysed from DGGE and they indicated the presence of bacteria from the genera Geobacillus, Bacillus, Brevibacillus, Thermus and uncultured sulphate reducing bacteria. Some of which have been reported in other Antarctic geothermal sites. Geobacillus, Bacillus and Brevibacillus genera were successfully cultivated in an enriched medium. A pure culture of one thermophilic Geobacillus bacterium was obtained closely related to Geobacillus jurassicus.

We observed ice formation and water column attributes in four shallow Antarctic ponds between January and 7 April 2008. During that time ponds went from ice-free to > 80 cm thick ice, near-freshwater to hypersaline, well-lit to near darkness and temperatures fell to below zero. Here we examine shifts in biological activity that accompanied these changes. During February, freeze-concentration and ongoing photosynthesis increased dissolved oxygen concentration to up to 100 mg l-1, with a near-equivalent decrease in dissolved inorganic carbon and a pH rise. Benthic photosynthesis was responsible for 99% of estimated biological oxygen production. Net oxygen accumulation ceased in late February, pH began to fall and inorganic carbon to increase, but the pool of dissolved oxygen was depleted only slowly. Anoxia had been attained in only one pond by April and there was little accumulation of indicators of anaerobic activity. The nitrogen and phosphorus balances of the ponds were dominated by organic forms, which, like DOC and CDOM, behaved conservatively. Conversely, inorganic nitrogen and phosphorus uptake was evident throughout the study period, at a molar ratio of 16N:1P in two of three ponds, consistent with uptake into biological material. We found no coupling between N and P uptake and photosynthesis.

Capture by water surfaces is a frequent but stochastic phenomenon for Antarctic collembolans (springtails), with implications for both the survival and dispersal of populations. This paper provides the first field description of the characteristics of rafting aggregations of the springtail Gomphiocephalus hodgsoni and provides the first observation of the inclusion of the mite, Stereotydeus mollis, within these aggregations. Field observations of aggregations in meltwater pools are used to develop a picture of the ecological implications of rafting for Antarctic springtails. The potential for marine capture was also demonstrated by additional observations of two springtails aerially deposited on to sea ice as well as springtails floating in the tidewater cracks between the sea ice and land.

Concentration and isotope composition of particulate organic matter were analysed from five coastal sites on the annual fast ice and in the underlying water column at Terra Nova Bay. The highest increases of POC (< 2767 μM C) and PON (< 420 μM N) were reached in bottom ice and the unconsolidated platelet layer, linked with a large accumulation of nutrients and dissolved organic matter. Isotope POM composition in ice habitats was highly varied (δ13CPOC: -30.7 to -15.0‰, δ15NPON: 1.8–9.9‰). Constant negative δ13CPOC (> -29.3‰) and positive δ15NPON (< 9.4‰) values characterized the upper ice horizons, indicating the prevalence of aged detritus in these assemblages. By contrast, isotope composition (δ13CPOC: -15.0 to -29.7‰, δ15NPON: 1.8–9.6‰) and POC/PON ratios (6.2–12.6) changed markedly in bottom ice and interstitial water, even on short time scales, because of the combined effects of internal growth and mixing among freshly produced biomass. Sea ice breakout caused a large settling of particulates in the water column. It changed δ13CPOC (from 7.9 to 1.8‰) and δ15NPON (7.9–1.8‰) values in suspended particulate matter, indicating that inputs from fast ice strongly affect the isotopic signature of the particulate assemblage Antarctic coastal waters.

During RV Polarstern cruise ANT-XXIII/4 in 2006, a gravity core (PS 69/335-2) and a giant box core (PS 69/335-1) were retrieved from Maxwell Bay off King George Island (KGI). Comprehensive geochemical (bulk parameters, quantitative XRF, Inductively Coupled Plasma Mass Spectrometry) and radiometric dating analyses (14C, 210Pb) were performed on both cores. A comparison with geochemical data from local bedrock demonstrates a mostly detrital origin for the sediments, but also points to an overprint from changing bioproductivity in the overlying water column in addition to early diagenetic processes. Furthermore, ten tephra layers that were most probably derived from volcanic activity on Deception Island were identified. Variations in the vertical distribution of selected elements in Maxwell Bay sediments further indicate a shift in source rock provenance as a result of changing glacier extents during the past c. 1750 years that may be linked to the Little Ice Age and the Medieval Warm Period. Whereas no evidence for a significant increase in chemical weathering rates was found, 210Pb data revealed that mass accumulation rates in Maxwell Bay have almost tripled since the 1940s (0.66 g cm-2 yr-1 in ad 2006), which is probably linked to rapid glacier retreat in this region due to recent warming.

Many different polychaete-echinoderm relationships have been described, from tropical to polar environments. Most of these associations have been generally defined as ‘commensal’, with polychaetes guests usually found on the oral surface of their hosts or, in a very few cases, even inside the host's body. Here we present an inquilinistic association involving two Antarctic species, the polychaete Gorekia crassicirris (Willey, 1902) (Polynoidae) and the irregular sea urchin Abatus nimrodi (Koheler, 1911) (Schizasteridae) found in the Ross Sea. This record is only the second worldwide for this kind of association, after that of the polychaete Benthoscolex cubanus which lives in the gut of the spatangoid Archeopneustes hystrix in Caribbean waters. Gorekia crassicirris seems to be a polyxenous species as it was also observed on another schizasterid, Brachysternaster chescheri Larrain, 1985 in the Weddell Sea. Considering that A. nimrodi is absent from that area and that the two sea urchin species have a disjoint distribution, it is possible that a ‘host-switch’ phenomenon occurred at some stage. We review the available literature to compare the Antarctic pairing with the other known examples of similar associations.

The nematode communities of Antarctica are considered simple. The few species present are well adapted to the harsh conditions and often endemic to Antarctica. Knowledge of Antarctic terrestrial ecosystems is increasing rapidly, but nematode communities remain to be explored in large parts of Antarctica. In soil samples collected at Byers Peninsula (Antarctic Specially Protected Area No. 126), Livingston Island we recorded 37 nematode taxa but samples showed great variation in richness and abundance. Nematode richness decreased with increasing soil pH, whereas total abundances, and the abundance of several trophic groups, were greatest at intermediate pH (around 6.5–7). Moreover, the community composition was mainly related to pH and less so to soil moisture. Trophic group, and total nematode, rotifer and tardigrade, abundances were generally positively correlated. Byers Peninsula is thus, by maritime Antarctic standards, a nematode biodiversity hotspot, and the presence of several previously unrecorded genera indicates that nematode species richness in maritime Antarctica is probably underestimated. Our results indicate that abiotic factors influence nematode communities with little evidence for biotic interactions. The unexplained heterogeneity in community composition is probably related to variation in microclimate, vegetation, topography and unmeasured soil properties, but may also be contributed to by biological processes.

The increase of tourism to the Antarctic continent may entail not only local but also global environmental impacts. These latter impacts, which are mainly caused by transport, have been generally ignored. As a result, there is a lack of data on the global impacts of Antarctic tourism in terms of energy consumption and carbon dioxide emissions. This paper presents and applies a methodology for quantifying CO2 emissions, both for the Antarctic vessel fleet as a whole and per passenger (both per trip and per day). The results indicate that the average tourist trip to Antarctica results in 5.44 t of CO2 emissions per passenger, or 0.49 t per passenger and day. Approximately 70% of these emissions are attributable to cruising and 30% to flying, which highlights the global environmental relevance of local transport for this type of tourism.

Fluxes of dissolved oxygen and nutrients and vertical fluxes of particulate organic elements were investigated in the subtidal benthic environment of Marian Cove, King George Island, Antarctica, using in situ benthic chambers and near-bottom sediment traps. Fluxes of dissolved oxygen, ammonium, phosphate, and silicate were comparable to those measured in temperate regions. Sediment oxygen consumption was a good indicator of organic respiration and elemental efflux at the benthic boundary layer of Marian Cove, with good positive correlations with ammonia (r2 = 0.67), phosphate (r2 = 0.57), and the C:N:P ratio (106:11.5:1.15) in the chamber water. A positive relationship (r2 = 0.58) between settling particulate organic carbon flux and chl a concentration suggests that water column biomass and production are direct sources of settling particles. According to element budgets in summer assessed using the fluxes, Jin and the sum of Jout and Jburial were 15.9 ± 8.1 and 22.6 ± 8.2 mmol m-2 d-1 for carbon, 2.02 ± 0.54 and 2.46 ± 0.82 mmol m-2 d-1 for nitrogen, 0.07 ± 0.03 and 0.23 ± 0.08 mmol m-2 d-1 for phosphorus, and 12.4 ± 2.7 and 13.5 ± 5.0 mmol m-2 d-1 for silicon, respectively. There was a broad balance between sediment organic input and remineralized output for carbon and nitrogen at the benthic boundary layer of Marian Cove.

Southern elephant seals Mirounga leonina within the Kerguelen province disperse between Marion Island (MI), Iles Crozet (IC) and Iles Kerguelen (IK) despite the high site fidelity characteristic of this species. From 1987–2002, 199 IC individuals, or 11.63% of the tagged population there, were resighted at MI. Resights of IC seals at MI peaked during the juvenile moult and seals aged 0–2 represent 66% of all resights made. Equal numbers of male and female seals (all age classes) were dispersing. Dispersing breeding females (n = 22, on 33 occasions) outnumbered dispersing breeding males (n = 6, on 16 occasions), after initially emigrating from IC to MI as juvenile seals (natal dispersal). Greater male-mediated gene flow was ultimately attained due to the polygynous mating system and some extremely successful males. Of 132 seals fitted with satellite-relay data loggers at MI, six hauled out at IC and three at IK. Two of the seals which migrated to IC were born at MI; all others were unmarked males likely to be native to IC or IK. Dispersal should ideally be considered when assessing vital rates for southern Indian Ocean elephant seal populations.

The Triassic Lashly Formation occurs to the east of Mount Brooke at Coombs Hills. Previously established informal members B, C, and D of the Lashly Formation are now identified at Coombs Hills. Lashly Formation member D passes up into a poorly exposed interval of silicic shard-bearing fine-grained sandstone and tuff, which is correlated with the Jurassic Shafer Peak Formation of north Victoria Land and Hanson Formation of the Beardmore Glacier region. Lashly Formation members C and D are intruded by three phreatic explosion pipes, resulting from emplacement of Ferrar Dolerite intrusions at depth and associated explosive steam generation. These pipes, ranging up to 180 m in horizontal dimension, comprise sedimentary clasts in a sand matrix, most of which was locally derived. Pipe margins are mainly ill defined and adjacent country rock is commonly disaggregated or shattered, although retaining stratigraphic order. Locally, thin basalt intrusions have interacted with coal beds.