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.

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.

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.

Organochlorine contaminants (OCs) and polybrominated diphenyl ethers (PBDEs) were investigated in the eggs of five bird species from the South Shetland Islands. Additionally, OCs and PBDEs were also analysed in embryos of two species. The concentration ranges in eggs were (ng g-1 wet weight) 2.11 to 541 for polychlorinated biphenyls (PCBs), <0.25 to 0.88 for PBDEs, 2.45 to 405 for p,p’-DDE and 1.50 to 603 for mirex. The PCBs were predominant in the eggs of Macronectes giganteus, Catharacta antarctica and Larus dominicanus, whereas hexachlorobenzene (HCB) was the major compound found in the eggs of Pygoscelis antarcticus and Sterna vittata. The PBDE congeners were detected only in the eggs of C. antarctica (PBDE 47 and 153) and S. vittata (PBDE 47). There were differences in OC concentrations of up to two orders of magnitude between M. giganteus embryos which were related to the development stage and OC concentrations in the respective eggs. Trophic ecology and post-breeding dispersal exerted an influence on contaminant patterns. Comparisons with data from the literature indicate an increase in the concentrations of some OCs over recent years.

The Ross Sea polynya is one of the most productive regions in the Southern Ocean. However, limited access and high spatio-temporal variability of physical and biological processes limit the use of conventional oceanographic methods to measure early season primary productivity. High-resolution observations from two Seagliders provide insights into the timing of a bloom in the southern Ross Sea polynya in December 2010. Changes in chlorophyll and oxygen concentrations are used to assess bloom dynamics. Using a ratio of dissolved oxygen to carbon, net primary production is estimated over the duration of the bloom showing a sensitive balance between net autotrophy and heterotrophy. The two gliders, observing spatially distinct regions during the same period, found net community production rates of -0.9±0.7 and 0.7±0.4 g C m-2 d-1. The difference highlights the spatial variability of biological processes and is probably caused by observing different stages of the bloom. The challenge of obtaining accurate primary productivity estimates highlights the need for increased observational efforts, particularly focusing on subsurface processes not resolved using surface or remote observations. Without an increased observational effort and the involvement of emerging technologies, it will not be possible to determine the seasonal trophic balance of the Ross Sea polynya and quantify the shelf’s importance in carbon export.

It has been demonstrated that persistent organic pollutants (POPs) can affect the immune system of mammals and birds. In this study, the concentration of different POPs and leukocytes in blood samples from three chinstrap penguin (Pygoscelis antarctica) populations was analysed in order to assess the impact on haematological parameters. Using blood sample smears, basophils, eosinophils, heterophils, lymphocytes and monocytes were quantified. Mature and immature red blood cells were counted and cell alterations in both white and red blood cells were analysed. At the same time, whole blood was analysed for POPs. The results showed that contaminants, such as dichlorodiphenyltrichloroethane and its metabolites (ΣDDT), as well as polychlorinated biphenyls (ΣPCB), had significant correlations to eosinophils, lymphocytes and heterophils. This indicates possible immunohaematological alterations derived from exposure to such contaminants. Cytological alterations were also observed, such as cytotoxic granules, toxic heterophils, and atypical and granulated lymphocytes, which would demonstrate that these seabirds are being exposed to stress agents that could be producing some alterations at a leukocytary cellular level.

The theory of propagation in a direction almost parallel to the Earth’s magnetic field is reviewed, calculating the group refractive index of the ordinary ray in the presence of electron-neutral collisions. An electron density profile is estimated from the ordinary trace and is used to compute the z-ray trace. It is shown that this reconstruction can help to identify the rare cases of z-rays from among the numerous cases of duplicate ordinary traces, due to reflection from two different directions.

The development of coastal polynyas, areas of enhanced heat flux and sea ice production strongly depend on atmospheric conditions. In Antarctica, measurements are scarce and models are essential for the investigation of polynyas. A robust quantification of polynya exchange processes in simulations relies on a realistic representation of atmospheric conditions in the forcing dataset. The sensitivity of simulated coastal polynyas in the south-western Weddell Sea to the atmospheric forcing is investigated with the Finite-Element Sea ice-Ocean Model (FESOM) using daily NCEP/NCAR reanalysis data (NCEP), 6 hourly Global Model Europe (GME) data and two different hourly datasets from the high-resolution Consortium for Small-Scale Modelling (COSMO) model. Results are compared for April to August in 2007–09. The two coarse-scale datasets often produce the extremes of the data range, while the finer-scale forcings yield results closer to the median. The GME experiment features the strongest winds and, therefore, the greatest polynya activity, especially over the eastern continental shelf. This results in higher volume and export of High Salinity Shelf Water than in the NCEP and COSMO runs. The largest discrepancies between simulations occur for 2008, probably due to differing representations of the ENSO pattern at high southern latitudes. The results suggest that the large-scale wind field is of primary importance for polynya development.

Ice shelves fringing Antarctica are sensitive indicators of climate change due to the direct interface with the atmosphere and ocean. Meltwater induced by atmospheric warming percolates from the surface into hydrofractures and affects shelf stability. Surface melting reduces the microwave backscattering; thus backscatter data is useful in melt monitoring. The Ku-band scatterometer derived melting index (MI) was utilized to assess the decadal (2000–10) variability observed over Antarctic ice shelves. The low intensity melting observed over large ice shelves and high intensity melting observed over the Larsen, Amery, West and Shackleton ice shelves are discussed. A correlation of around 93% was observed between MI variation and rift propagation over Amery Ice Shelf. The El Niño and the Southern Oscillation (ENSO) correlation with MI was also investigated. The paper highlights that scatterometer derived information has the potential to assess meltwater production and rift propagation.

Based on data from low elevation lake sites, previous studies have suggested three quantitative relationships related to summer (December, January and February) air temperatures in the Dry Valleys of Antarctica: i) decrease with altitude at the dry lapse rate of 9.8°C km-1, ii) increase with distance from the coast at a rate of 0.09°C km-1, and iii) degree-days above freezing during the summer months is logarithmically proportional to the maximum summer air temperature. Here, we tested the first two of these rules at high elevation sites in Upper Wright Valley. Direct measurements confirmed that the summer lapse rate followed the dry lapse rate. For the three furthest stations, Tyrol Valley, Mount Fleming and Horseshoe Crater, the average difference between the measurements and the predicted summer monthly averages are -2.1±1.4°C, -0.5±1.0°C and -0.4±0.9°C, respectively. By contrast, at Linnaeus Terrace (54 km from the coast) the monthly average is warmer than predicted by several degrees: +4.3±1.3°C. The inland temperature gradient at these high elevation sites may result from sunlight effects rather than coastal wind as previously shown for the lower valleys. The warm conditions observed c. 50 km from the coast may reflect a zone affected by both sunlight and coastal wind.