The incubation-limitation hypothesis suggests that clutch size in some birds is limited by incubation capacity. However, this remains disputed amongst ornithologists. This study aimed to test whether incubation capacity limits the maximum clutch size to two eggs in south polar skuas (Catharacta maccormicki Saunders) by comparing the egg and nest temperatures as well as hatchability between two-egg and three-egg clutches. Although the vast majority of clutches contained one or two eggs, four naturally occurring three-egg clutches were found at Barton Peninsula, King George Island over three breeding seasons (2004–2005, 2005–2006 and 2006–2007). Regardless of clutch size, all incubating parents exhibited two discernible brood patches. The mean egg and nest temperatures of the three-egg clutches were significantly lower than were those of the two-egg clutches. The accumulated time that egg temperature decreased below 30°C in three-egg clutches was approximately eight times longer than that in two-egg clutches. The hatchability of natural one-egg (89.5%) and two-egg clutches (95.4%) were significantly higher than that of the three-egg clutches, which was zero. Our results suggest that the maximum clutch size in south polar skuas is probably restricted by incubation capacity.

Quantitative real time PCR is the most sensitive and widely used method for the analysis of gene expression. The choice of one or several reference genes is very important for a normalization process, which should not fluctuate under stress conditions, to reduce error rate and bias during experimental procedure. In the present study, the expression stability of nine reference genes (two actins, two tubulins, two elongation factor 1α, two ubiquitins, and cyclophilin) during abiotic stresses such as cold, salt, and PEG treatments, was evaluated on Deschampsia antarctica plants using geNorm software. Results from various experimental conditions indicated that cyclophilin and elongation factor 1α were the most stable genes in the leaf and the root, respectively. The expression of the other reference genes varied under stress. The relative quantification of the TACR7 gene varied according to the kind and the number of reference genes used, suggesting the importance of considering the implications of a combination of reference genes under different stress conditions and in different tissues.

During the summer 2005/06, an oceanographic cruise was carried out in the Ross Sea, from Cape Adare, through the Terra Nova Bay polynya to the eastern edge of the Ross Ice Shelf. We analysed microbial activities (prokaryotic carbon production, protease, phosphatase, beta-glucosidase and lipase activity) and bacterial community structure (using Denaturing Gradient Gel Electrophoresis - DGGE) in order to establish if differences in bacterioplankton assemblages and their metabolic requirements occur within the five Ross Sea water masses: Antarctic Surface Waters (AASW), High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW), Antarctic Bottom Water (AABW), Circumpolar Deep Water (CDW). Differences in activities were found between the highly active AASW and all the other water bodies. A Principal Component Analysis highlighted two main gradients: in the Cape Adare area (AASWn, CDW and AABW) higher phosphatase, lipase and glycolytic activities, increasing towards the surface, were identified, whereas in the southern sector of the basin [AASWs and (m)HSSW] higher leucine uptake and polypeptide degradation characterized the second gradient. DGGE fingerprinting showed for the first time that different water masses harboured diverse bacterial communities, highlighting the high specificity of deep water assemblages. Alpha- and Gammaproteobacteria represented the main phylogenetic groupings in all samples and no substantial difference in the phylogenetic composition of assemblages was found between different water masses.

Three temporary Automatic Weather Stations measured summertime surface layer climate over the Darwin–Hatherton Glacial system. These data were used to test a Polar optimized Weather Research and Forecasting model (Polar-WRF) simulation for December as a case study. Observations show differences in hourly averaged solar and net all-wave radiation between white ice and blue ice areas (BIAs). Although the down-welling solar radiation is higher over the white ice region, the net all-wave energy is higher over the BIA. Derived albedo for each surface type confirms that the blue ice areas have lower albedo. Also, the hourly averaged temperatures are higher at lower elevation stations, creating a gradient towards the Ross Ice Shelf. Analysis shows that there is a diurnal oscillation in strength and intensity of the katabatic wind. The two lower stations register a distinct reversal of wind direction in the early afternoon due to intrusion of an anabatic circulation. Anabatic winds are not prevalent further up the Darwin Glacier. A high-resolution Polar-WRF simulation as a case study shows good agreement with observations. The December 2008 case study is characterized by a strong south-westerly katabatic wind over Hatherton, whereas the flow over Lower Darwin was diurnally reversing. Polar-WRF shows that the katabatic front advanced and retreated periodically between Hatherton and Lower Darwin.

This study concerned the fragility of maritime Antarctic soils under increasing temperature, using the C dynamics and structural characteristics of humic substances as indicators. Working with four representative soils from King George Island (Lithic Thiomorphic Cryosol (LTC1 and LTC2), Ornithogenic Cryosol (OG) and Gelic Organosol (ORG)) we evaluated the total organic C and nitrogen contents, the oxidizable C and humic substances. Soil samples were incubated to assess the amount of C potentially mineralizable at temperatures typical of an Antarctic summer (5–14°C). Humic acids showed a higher aliphatic character and a smaller number of condensed aromatic groups, which suggests that these molecules from Antarctic soils are generally less resistant to microbial degradation than humic acids molecules from other regions. Based on 13C NMR spectra of MAS and CP/MAS, samples of soil humic acids of mineral soils (LTC1 and LTC2) have a higher content of aliphatic C, and heteroatom C, with lower levels of carbonyl and aromatic C, when compared with organic matter-rich soils (OG and ORG). Increasing incubation temperature led to a higher rate of mineralizable C in all soils. A sequence of soil fragility was suggested - LTC1 and LTC2 > OG > ORG - which showed a correlation with the Q10 coefficient and the ratio of labile and recalcitrant C fractions of soil organic matter (R2 = 0.83).

There has been growing concern over the impact of increased human disturbance and research effects on Antarctic species. The Weddell seal of McMurdo Sound in particular has been used as a model species for over four decades of research, with some individuals handled multiple times over a single season. Using opportunistic data, we performed an assessment of blood indicators in adult males (n = 26) and adult females (n = 24) based on high versus low disturbance areas, with results showing no variation in overall seal health. In addition, we performed a preliminary analysis of blood and faecal indicators of inflammation and stress collected from adult, non-lactating females (n = 13) handled twice in less than two weeks for research purposes. There was no indication of a change in white blood cells, platelets, globulins or haptoglobins, or faecal corticosteroids (all P > 0.05). While based on a small, opportunistic sample size with limited power in some cases, preliminary results indicate there is no acute impact of repeated handling or difference in overall traffic level on adult Weddell seals.

The biology and ecology of Cephaloziella varians, the most widespread and abundant liverwort in Antarctica, are reviewed. A description of the species is given, together with information on its geographical distribution, reproduction, habitats, associated organisms and responses to environmental stresses. Characteristics of its photosynthetic physiology are also presented, including data on oxygen evolution rates and chlorophyll a fluorescence parameters. Substratum and tissue chemistry, water relations and pigments are discussed, along with recent data demonstrating that the dark pigment in the apical leaves of C. varians is the anthocyanidin riccionidin A. Recent studies showing that the ericoid mycorrhizal symbiont Rhizoscyphus ericae is present in the tissues of the plant at a wide range of locations in the maritime and sub-Antarctic are also described. It is evident, from the literature reviewed, that C. varians has several adaptations that enable it to survive in the Antarctic biome, explaining its survival at higher latitudes than any other hepatic. The species’ major adaptations include the synthesis of riccionidin A in apical leaves, enabling efficient heat absorption and protection from photoinhibition, and the presence in stems and rhizoids of fungal hyphae, which are potentially beneficial to the hepatic’s nutrition and possibly also synthesize cryoprotectants.

Dense coral-sponge communities on the upper continental slope at 570–950 m off George V Land, East Antarctica have been identified as Vulnerable Marine Ecosystems. The challenge is now to understand their probable distribution on other parts of the Antarctic margin. We propose three main factors governing their distribution on the George V margin: 1) their depth in relation to iceberg scouring, 2) the flow of organic-rich bottom waters, and 3) their location at the head of shelf cutting canyons. Icebergs scour to 500 m in this region and the lack of such disturbance is a probable factor allowing the growth of rich benthic ecosystems. In addition, the richest communities are found in the heads of canyons which receive descending plumes of Antarctic Bottom Water formed on the George V shelf, which could entrain abundant food for the benthos. The canyons harbouring rich benthos are also those that cut the shelf break. Such canyons are known sites of high productivity in other areas due to strong current flow and increased mixing with shelf waters, and the abrupt, complex topography. These proposed mechanisms provide a framework for the identification of areas where there is a higher likelihood of encountering these Vulnerable Marine Ecosystems.

The liquid soil water contents in the seasonally thawed layer (active layer) were characterized from seven soil climate monitoring sites - four coastal sites from south to north (Minna Bluff, Scott Base, Marble Point and Granite Harbour), and inland sites from low to high altitude (Wright Valley, Victoria Valley and Mount Fleming). Mean water contents ranged from 0.013 m3 m-3 near the surface at Victoria Valley to 0.33 m3 m-3 near the ice-cemented layer at Granite Harbour. The coastal sites have greater soil water contents than the McMurdo Dry Valley and Mount Fleming sites, and moisture contents increase with depth in the active layer. The Wright Valley site receives very little infiltration from snowmelt, with none in most years. All other sites, except Mount Fleming, received between one and four wetting events per summer, and infiltrated water moved to greater depths (≈ 10–25 cm). The Scott Base and Granite Harbour sites are on sloping ground and receive a subsurface flow of water along the ice-cemented permafrost. Our findings indicate that water contents are low with very little recharge, are greatly influenced by the local microclimate and topography, and show no significant increasing or decreasing trend over 10 years of monitoring.

The Antarctic silverfish Pleuragramma antarcticum Boulenger is the dominant fish species in the high Antarctic zone, playing a key role in the Ross Sea midwater shelf ecosystem. Unlike other notothenioids, it is holoplanktonic species, spending its entire life cycle in the water column. Early life stages of P. antarcticum are generally found in the upper 200 m and their spatial distribution is largely affected by water masses and general circulation. To understand better the mechanisms involved in the geographical distribution of the Antarctic silverfish within the western Ross Sea, an analysis of abundance and distribution was carried out in relation to oceanographic conditions. Samples were collected in summer during the 1998, 2000 and 2004 Italian cruises, covering the majority of the western sector of the Ross Sea. Overall 127 stations were sampled using standard plankton nets for biological samples and CTD and XBT to record abiotic parameters. Although all surveys were in December–January, the yearly results differed in terms of relative abundance of larval developmental stages and of oceanographic characteristics. The 1997–98 samples were characterized by very low abundance overall and by the virtual absence of early larvae. In summers 1999–2000 and 2003–04 the abundance of P. antarcticum was one order of magnitude higher than in the earlier season. In 1999–2000 catches were mainly composed of pre-flexion larvae and late postlarvae, while in 2003–04 catches were made up of pre-flexion larvae and juveniles. In January 2000 the Ross Sea summer polynya was fully open as the pack ice was almost completely melted, whereas in January 1998 and 2004 the opening of the polynya was considerably delayed. As a consequence, a delay in phytoplankton blooms and a decrease in primary production were observed in the summer seasons 1998 and 2004 with respect to 2000. The spatial distribution of early life stages, that were confined to the continental shelf and shelf break of the Ross Sea, generally appeared to be positively influenced by transition zones (oceanographic fronts). In addition, most of catches were recorded on or in close proximity to the banks (Pennell, Mawson, Ross and Crary) that characterize the continental shelf of the Ross Sea. On the basis of present findings and literature data, a link between the general circulation in the western Ross Sea and the distribution pattern of the early life stages of P. antarcticum has been developed.

Meltwater habitats in the Darwin Glacier region, Victoria Land (80°S), were sampled in December 2007 and January 2009 to characterize their microbial and metazoan ecology, nutrient status and geochemistry. Targeted areas included terrestrial ponds of the Grant Valley, Lake Wellman, Tentacle Ridge and Diamond Hill, and supraglacial ponds and cryoconite holes of the lower Darwin Glacier. Geochemistry ranged from Na-Cl dominated terrestrial ponds to Na-HCO3 dominated, dilute supraglacial ponds and cryoconites. All showed the nitrate enrichment typical of inland ponds of Victoria Land (up to 13 g.l-1 NO3-N), with some precipitating nitratine (NaNO3) salt. Elevated pH indicated ongoing photosynthetic processes. Benthic microbial mats were thin and poorly developed, dominated by oscillatoriacean cyanobacteria. Nitrogen-fixing genera were generally absent and diatoms were rare. A large (20 μm long) Cyanothece species was the most abundant cyanobacterium in the water and in sediments of the cryoconites. DNA finger-printing identified distinct differences in cyanobacterial and bacterial community structure between the cryoconites, terrestrial ponds and ponds on glacial margins. Eleven metazoan species were identified, with rotifers being the most abundant. Pond substrate (terrestrial rock, ice-cored moraine or supraglacial ice) proved to be a more significant influence on biogeochemistry than other aspects of geography or climatic conditions.

Using archival photography and satellite imagery, we have analysed the rates of advance or retreat of 103 coastal glaciers on South Georgia from the 1950s to the present. Ninety-seven percent of these glaciers have retreated over the period for which observations are available. The average rate of retreat has increased from 8 Ma-1 in the 1950s to 35 Ma-1 at present. The largest retreats have all taken place along the north-east coast, where retreat rates have increased to an average of 60 Ma-1 at present, but those on the south-west coast have also been steadily retreating since the 1950s. These data, along with environmental information about South Georgia, are included in a new Geographic Information System (GIS) of the island. By combining glacier change data with the present distribution of both endemic and invasive species we have identified areas where there is an increased risk of rat invasion to unoccupied coastal regions that are currently protected by glacial barriers. This risk has significant implications for the surrounding ecosystem, in particular depletion in numbers of important breeding populations of ground-nesting birds on the island.

The levels and distribution of polychlorinated biphenyl (PCB) congeners were analysed in fourteen soil and eight lichen (Usnea aurantiaco-atra) samples from King George Island, West Antarctica. A total of 32 PCB congeners were found in five soil samples collected in 2006, and the mean concentration of total PCBs was 20.4 pg g-1 dry weight (range, 8.0−33.8 pg g-1 dry weight). The most abundant PCB isomers in soil samples were di-, tri-, and penta-CBs, which accounted for more than 75% of the total residues. Twelve dioxin-like PCBs were also detected in nine soil and eight lichen samples, and the levels of dioxin-like PCBs were 5-fold higher in lichens than in soil. PCBs were detected at very low levels in most soil and lichen samples. The highest congener concentrations were found for PCB 118 (6.63 and 21.93 pg g-1 in soil and lichen, respectively) among dioxin-like PCBs. PCB levels in air samples were highly correlated with those in soil and lichen samples, as were PCB levels in soil and lichen samples collected at the same site. Long-range atmospheric transport is thought to be the main source of PCBs on King George Island. However, PCB levels in soil and lichen samples were also apparently influenced by local sources of PCBs.

Ile Amsterdam (37°50′S, 77°30′E, 55 km2) and Ile Saint-Paul (38°43′S, 77°31′E, 7 km2) are very isolated volcanic islands which were originally colonized by a few invertebrate fauna and flora. Invasive species richness has then increased along with human activity. A three-year monitoring programme (1997, 2000, 2001) and a summer campaign (2007) allowed species diversity, host plants, abundance and phenology of introduced aphids and natural enemies to be described. Seven cosmopolitan aphid species have been found on Ile Amsterdam (Aulacorthum solani, A. circumflexum, Macrosiphum euphorbiae, Myzus ascalonicus, M. cymbalariae, M. ornatus and Rhopalosiphum padi) and three on Ile Saint-Paul (A. solani, M. cymbalariae and R. padi). On Ile Amsterdam, these aphids were found on 28 host plants (out of 57 sampled plants), mainly introduced species. Phylica arborea was the only native plant much colonized by one aphid species, A. circumflexum. Aphids were mainly present on the base or in this vicinity. One Hymenopteran parasitoid, Aphidius matricariae, and two hyperparasites (Dendrocerus aphidum and Phaenoglyphis villosa), probably introduced along with their host, were collected. Aphid activity is very low during the autumn (March–May) and at a maximum in spring and summer. Their density and diversity decrease with distance from the research station. From these results, the possible impact of aphids on native plants is discussed.

A prospecting search for antitumoural activity in polar benthic invertebrates was conducted on Antarctic and sub-Antarctic benthos in three different areas: Bouvet Island (sub-Antarctic), eastern Weddell Sea (Antarctica) and the South Shetland Islands (Antarctica). A total of 770 benthic invertebrate samples (corresponding to at least 290 different species) from 12 different phyla were assayed to establish their pharmacological potential against three human tumour cell lines (colorectal adenocarcinoma, lung carcinoma and breast adenocarcinoma). Bioassays resulted in 15 different species showing anticancer activity corresponding to five different phyla: Tunicata (5), Porifera (4), Cnidaria (3), Echinodermata (2) and Annelida (1). This appears to be the largest pharmacological study ever carried out in Antarctica and it shows very promising antitumoural activities in the Antarctic and sub-Antarctic benthos.

The temporal changes in dissolved inorganic (DIC) and organic carbon concentrations (DOC) were monitored from late autumn to spring 2006 in the Scholaert Channel, West Antarctic Peninsula. Surface DIC spanned a small range (2163.3 to 2194.5 μmol kg-1), increasing from late autumn to winter and then decreasing in spring. An excess of DOC (7.0–63.6 μmol l-1), against a deepwater background concentration of 44 μmol l-1, existed in the surface mixed layer throughout the sampling period. Mass-balance budgeting indicates that the DIC dynamics were primarily governed by remineralization in winter and by primary production in spring despite very low biomass of both autotrophic and heterotrophic organisms. The net community production (7.3 mmol C m-2 d-1) in spring was mainly partitioned to DOC accumulation (3.6 mmol m-2 d-1) and downward export of particulate organic carbon (POC) (2.9 mmol m-2 d-1) rather than POC accretion (0.8 mmol m-2 d-1) in the surface mixed layer. The study area acted as a source of CO2 to the atmosphere in winter (∼0.8 mmol m-2 d-1) and a sink in spring (2.3–5.3 mmol m-2 d-1), and hence was not a one-way CO2 sink as had been previously hypothesized for marginal sea ice zones.

We describe a long-range migration of a pre-moulting adult chinstrap penguin from Bouvetøya, a small relatively recently established colony, to the South Sandwich Islands, where large, established colonies of this species reside. The trip lasted around three weeks, covered ∼3600 km, and the time of arrival was consistent with the annual moult. The bird did not travel along the shortest path or along a constant bearing, but instead followed what appeared to be a series of two or three rhumb lines of constant bearing. Small southward and northward deviations from the general path were consistent with local water currents. Travel speeds were high during daylight but decreased at night, suggesting that resting or opportunistic feeding occurred preferentially at night. While long-range winter migrations of chinstraps to feeding areas in the vicinity of distant colonies have been previously described, this is the first observation of such a trip during the period between breeding and moulting, and the first record of an individual actually arriving at one of these distant colonies. This has implications for understanding population structure and management of this important Southern Ocean predator.

In this paper we review evidence for, and anticipated consequences of, climate change in Antarctic marine communities, examining the potential impacts on invertebrates and vertebrates alike and exploring plausible outcomes for species, with examples principally from the Antarctic literature. We suggest that industries with the greatest potential to aggravate climate change impacts on marine communities are marine capture fisheries. In the Southern Ocean, harvesting is governed under the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR). CCAMLR espouses an ecological management framework and so has the capacity to mitigate harvesting impacts such that they do not worsen impacts from climate change. We discuss some of the implications of climate change and advocate that CCAMLR address certain key issues if it is to fulfil its international obligations. It will be essential for CCAMLR to determine relative risks (uncertainties), impacts and timescales, of various processes consequent on climate change. Such risk assessments should be feasible with current knowledge and should provide a focus for future work. We believe it will be important to prioritize issues that reduce impacts and uncertainties by the greatest degree, and propose that future plans should involve shared responsibility (e.g. with SCAR etc.) for each of the risks described.

We report the establishment of two representatives of a new ecological functional group on the sub-Antarctic island of South Georgia - pollinating insects - in the form of the hoverfly Eristalis croceimaculata Jacobs (Diptera, Syrphidae) and the blowfly Calliphora vicina Robineau-Desvoidy (Diptera, Calliphoridae). The floricolous adults of these two species provide a new ecological role, pollination, in the ecosystems of this island. The activity of their respectively saprophogous or necrophagous larvae will also augment that of the native insect and microarthropod soil fauna. We discuss the potential new synergy between this functional group and that of a number of established non-native plants, reliant on insect pollinators for successful seed-set and hence dispersal, that are currently of persistent status with very limited local distributions.

Introduced house mice Mus musculus have recently been discovered to be significant predators of chicks of Tristan albatrosses Diomedea dabbenena and several burrowing petrels at Gough Island. We summarize evidence for mouse attacks on albatross chicks at sub-Antarctic Marion Island, where mice are also the only introduced mammal following the eradication of feral cats Felis catus in the early 1990s. Wounds consistent with mouse attacks have been found on wandering albatrosses Diomedea exulans since 2003 and dark-mantled sooty albatrosses Phoebetria fusca in 2009. To date, attacks on wandering albatross chicks have been infrequent, affecting <1% of chicks in study colonies, and only about half of the attacks have been fatal. Small chicks may also die when mouse burrows collapse under chicks, trapping them. Mouse attacks appear to be a recent phenomenon, supporting the contention that mice pose a significant threat when they are the only introduced mammal species. Ongoing monitoring is needed to assess whether the impacts of mice increase over time. Our observations add impetus to calls for the eradication of mice from Marion Island.