Chinstrap penguins (Pygoscelis antarcticus) show little sexual dimorphism and sexing by direct observation can be difficult. Through molecular techniques, male and female adults were identified at Stinker Point, Elephant Island, South Shetland Islands, in the 2011–12 and 2012–13 breeding seasons. In the assessment of sexual dimorphism using morphological characteristics, males were 6.0–9.4% larger than females. From the most significant morphological measurements, a discriminant function was formulated that classified 80.6% of the birds correctly. In addition, our data on bill length and depth were compared with those in the literature to evaluate sexual dimorphism between different breeding locations and to test the performance of the discriminant function. There were no differences in sexual dimorphism between breeding locations. However, the discriminant function should be used with caution because some penguins may be misclassified. Therefore, when there is doubt about the accuracy of morphometric approaches, application of molecular sexing techniques is recommended.

During the research programme conducted on the OV Puerto Deseado in the summers of 2011 and 2013, 36 stations were sampled using a demersal net at depths between 53–590 m in the Antarctic Peninsula and South Shetland Islands. A total 3378 fish specimens belonging to 36 species were recorded. Notothenidae was the best-represented family in species number, with Lepidonotothen nudifrons, L. larseni and Trematomus scotti being the most numerous species. Of the fish assemblages, 20% of the species were considered as dominant, 10% as common, 13% as occasional and 57% as rare. Six groups (and two sub-groups) were obtained by the ordination diagram based on geographical location: group 1=Gerlache Strait, group 2=Deception Islands, group 3=Biscoe Island, group 4=between Elephant and King George islands, group 5=northern Antarctic Peninsula, and group 6=South Shetland Islands, with sub-groups 6a shallower South Shetland Islands and 6b deeper South Shetland Islands. Sampling depth and water temperature significantly explained the spatial pattern. A latitudinal pattern of decreasing abundance from north-east to south-west was found in L. larseni and the opposite in T. scotti. The predictability of fish composition in the assemblages’ areas could be a useful tool for ecosystem-based management.

The new genus and species Bicoloromyces kyffinensis is described as new to science from a sterile crustose lichen, perhaps Lecanora fuscobrunnea or Lecidella sp. from Ebony Ridge of Mount Kyffin, Antarctica. The fungus recalls superficially the lichenicolous species referred to Taeniolella, but differs in having semi-macronematous conidiophores, tissues encrusted with calcium oxalate, aeruginose to blue-black colouration under the microscope, and conidia which are distoseptate and formed in basipetal chains. Energy dispersive spectroscopy established that the encrustations were of calcium oxalate. Differences from genera of rock-inhabiting fungi described from the Antarctic are discussed. This appears to be the furthest south any lichen-inhabiting fungus has been reported.

The McMurdo Dry Valleys of Antarctica are a climate-sensitive ecosystem, where future projected climate warming will increase liquid water availability to release soil biology from physical limitations and alter ecosystem processes. For example, many studies have shown that CO2 flux, an important aspect of the carbon cycle, is controlled by temperature and moisture, which often overwhelm biotic contributions in desert ecosystems. However, these studies used either single-point measurements during peak times of biological activity or diel cycles at individual locations. Here, we present diel cycles of CO2 flux from a range of soil moisture conditions and a variety of locations and habitats to determine how diel cycles of CO2 flux vary across gradients of wet-to-dry soil and whether the water source influences the diel cycle of moist soil. Soil temperature, water content and microbial biomass significantly influenced CO2 flux. Soil temperature explained most of the variation. Soil CO2 flux moderately increased with microbial biomass, demonstrating a sometimes small but significant role of biological fluxes. Our results show that over gradients of soil moisture, both geochemical and biological fluxes contribute to soil CO2 flux, and physical factors must be considered when estimating biological CO2 flux in systems with low microbial biomass.

Phytoplankton (>15 µm) was investigated in three shallow coastal areas at Admiralty Bay (AB) between the summers of 2002–03 and 2008–09. Phytoplankton abundance was low (103 cells l-1) and, over time, the prevailing cell size decreased due to a shift in phytoplankton dominant species from diatoms to dinoflagellates. In situ and remote sensing data showed that oscillations in sea surface temperature, precipitation, ice formation/melting, irradiance (cloud cover) and bottom circulation (indexed by the Antarctic Oscillation Index; AAO) were shown to govern the structure of the phytoplankton. Under negative AAO, diatoms prevailed, with the dominance of large (>80 µm) benthic diatoms (e.g. Corethron pennatum and Navicula directa) in periods of low production (102 cells l-1 in 2002–03), and medium-sized (31–80 µm) centrics (e.g. Thalassiosira spp. and Stellarima microtrias) when the abundance was higher (104 cells l-1 in 2003–04). Conversely, positive AAO led to the co-dominance of dinoflagellates and planktonic diatoms (e.g. Pseudo-nitzschia spp.) in the summers of 2007–08 and 2008–09. These results suggest that the AAO can be a good predictor of phytoplankton in coastal areas around the western Antarctic Peninsula, and may help our understanding of changes in other trophic levels of the food web.

Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.

Several recent papers have criticized the scientific robustness of the fisheries management system used by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), including that for Ross Sea toothfish. Here we present a response from the wider CCAMLR community to address concerns and to correct some apparent misconceptions about how CCAMLR acts to promote conservation whilst allowing safe exploitation in all of its fisheries. A key aspect of CCAMLR’s approach is its adaptive feedback nature; regular monitoring and analysis allows for adjustments to be made, as necessary, to provide a robust management system despite the statistical uncertainties inherent in any single assessment. Within the Ross Sea, application of CCAMLR’s precautionary approach has allowed the toothfish fishery to develop in a steady fashion with an associated accumulation of data and greater scientific understanding. Regular stock assessments of the fishery have been carried out since 2005, and the 2013 stock assessment estimated current spawning stock biomass to be at 75% of the pre-exploitation level. There will always be additional uncertainties which need to be addressed, but where information is lacking the CCAMLR approach to management ensures exploitation rates are at a level commensurate with a precautionary approach.

Early life history traits of the blackfin notothen, Trematomus scotti, were investigated through otolith microincrement pattern and stomach content analyses. Post-larval specimens of 12–20 mm standard length (SL) were collected in the Bransfield Strait and adjacent waters during the 2010–11 summer. Catches were unevenly distributed across the surveyed area, yielding a relative abundance of 0.3–3.6 specimens per 1000 m3 of filtered sea water. Age estimates ranged from 34 to 67 days, with good consistency and no apparent bias between readings. Based on an exponential model fitted to the age-length dataset, the growth rate was 0.17 mm day-1, corresponding to a daily percentage increment in size of 1.07% SL. In agreement with previous studies, larval hatching occurred at a mean size of 9.0 mm and was spread over a relatively short period, lasting from late December to late January. Prey composition consisted exclusively of copepods, mainly larval stages of copepodites. Feeding intensity ranged from 1–14 prey items per stomach, being positively correlated with larval fish size. In summary, T. scotti shares a common early life history strategy with several other notothenioids, consisting of small larvae hatching in summer and overwintering as pelagic early juveniles until the following summer season.

The management of sediment and water contamination from legacy waste is a significant problem in Antarctica. Although several reports have noted that there are contaminated sites at the abandoned Wilkes Station, a systematic attempt to assess the spatial scale of the problem has not been made, making development of clean-up or preservation programmes difficult. A contaminated site assessment for the old Wilkes Station and surrounds is presented in this paper. The Australian and New Zealand Environment and Conservation Council (ANZECC) sediment and water quality guidelines and background concentration levels (BCL) were used to assess the extent of contamination across Clark Peninsula. Of 67 sediment sites sampled, 72% were contaminated with at least one metal or metalloid, with values exceeding the ANZECC ISQG-High or 2 x BCL. Moreover, 19% were contaminated with four or more metals/metalloids. Of the 93 water samples collected, all but one was contaminated with at least one metal/metalloid concentration exceeding the guidelines, and 96% were contaminated with two or more metals/metalloids. For hydrocarbons in sediment and water, most samples were below quantitation limits. There is a complex pattern of contamination across Clark Peninsula that needs to be considered in future waste treatment, containment or removal operations, and for protection of heritage items.

Primary, tail and body moult of three seabirds from Tristan da Cunha archipelago were studied by castnetting offshore south Brazil from February 2006 to August 2007. Timing, duration and synchronization of primary and tail moult are described relative to the annual calendar. Body moult overlapped breeding in Atlantic yellow-nosed albatrosses (Thalassarche chlororhynchos), but tail and primary moult did not. Spectacled petrels (Procellaria conspicillata) had protracted body moult, whereas primary and tail moult were completed by August. We documented onset of primary moult during chick-rearing in spectacled petrels and great shearwaters (Puffinus gravis) of unknown breeding status, and suggest that the south-west Atlantic Ocean holds important numbers of moulting birds of both species during the summer–early autumn. The albatrosses and the spectacled petrels replaced rectrices alternately. Great shearwaters replaced rectrices outward, starting at the central pair. Primary, tail and body moult largely overlap in all three species, suggesting that the metabolic costs of primary moult may not be overly restrictive. Metabolic and nutritional ability to afford simultaneous moult of different feather tracts support the idea that impaired flight caused by wing moult is a strong factor driving no overlap of primary moult and breeding.

The aim of this study was to clarify the trophic patterns of the key species Pleuragramma antarctica in the Dumont d’Urville Sea, through its development and possible changes according to sampling locations. Variability in diet composition of larvae, juvenile and adult P. antarctica was analysed using fatty acid markers. Analysis of lipid class in P. antarctica reflected lipid accumulation with increasing size at all sampling stations. The fatty acid composition of triacylglycerol highlighted ontogenetic changes in the diet. Phytoplankton markers, such as C16PUFA:C16 and EPA:DHA ratios >1, and carnivorous markers in larvae suggested an omnivorous diet. Comparison between the fatty acid signature of P. antarctica older stages (juveniles and adults) and zooplankton species using OPLS-discriminant analysis indicated that juveniles fed mainly on euphausiid larvae and to a minor extent on copepods, and confirmed that non-herbivorous copepods were the main prey for adults. Our results suggest that different feeding patterns and a generalist strategy in P. antarctica with juveniles feeding on bigger prey than adults, probably as a result of prey availability according to their vertical segregation pattern.

Wright Valley, Victoria Land contains numerous aquatic habitats suitable for the growth of algae in summer. Excepting diatoms and lichen phycobionts, algal diversity and distribution in the valley was documented. Using cultures and environmental cloning eight cyanobacterial and 14 eukaryotic species were revealed. The cyanobacterium Microcoleus vaginatus and the chlorophycean Chlorococcum sp. 1 were the most common, both occurring in more than one habitat (ponds, soils or streams). Ponds harboured the most diverse communities. Habitat specialization was rare. Chlamydomonads were not found outside ponds, but species capable of zoospore production were able to colonize ponds and soils. Nostocalean cyanobacteria were not detected. Results suggest dispersal within and between valleys, with little evidence of Antarctic endemism. All but one cyanobacterium with similar internally transcribed spacer (ITS) length to clones from Miers Valley proved to be different species when 16S rRNA gene sequences were also considered; thus, ITS length is unreliable for assessing identity and biogeography of these cyanobacteria. Comparison with a 454 16S rRNA gene soil dataset from Wright Valley indicated the occurrence of only one of the cyanobacterial species, the distribution of which may be limited by salinity.

Microbial mats are common in polar streams and often dominate benthic biomass. Climate change may be enhancing the variability of stream flows in the Antarctic, but so far studies investigating mat responses to disturbance have been limited in this region. Mat regrowth was evaluated following disturbance by experimentally scouring rocks from an ephemeral McMurdo Dry Valley stream over two summers (2001–02 and 2012–13). Mats were sampled at the beginning and resampled at the end of the flow season. In 2012–13, mats were additionally resampled mid-season along with previously undisturbed controls. In 2001–02 rocks regained 47% of chlorophyll a and 40% of ash-free dry mass by the end of the summer, while in 2012–13 rocks regrew 18% and 27%, respectively. Mat stoichiometry differed between summers, and reflected differences in biomass and discharge. Oscillatoria spp. were greatest on scoured rocks and Phormidium spp. on undisturbed rocks. Small diatoms Humidophila and Fistulifera spp. increased throughout the summer in all mats, with the latter more abundant in scoured communities. Collectively, these data suggest that mats are variable intra-annually, responsive to hydrology and require multiple summers to regrow initial biomass once lost. These results will aid the interpretation of long-term data, as well as inform Antarctic Specially Managed Area protocols.