An assessment is made of the ability of the Coupled Model Intercomparison Project 5 (CMIP5) models to represent the seasonal cycles of biogeochemistry of the Ross Sea over the late twentieth century. In particular, sea surface temperature, sea ice concentration, surface chlorophyll a, nitrate, phosphate and silicate, and the depth of the seasonal thermocline (measuring vertical mixing) are examined to quantify the physical-biogeochemical capabilities of each model, and to provide for ‘ranked’ model ensembles. This permits critical assessment of modelled Ross Sea biogeochemical cycling, including less well observed variables such as iron and vertically integrated primary production. The assessment enables determination of model output confidence limits; these confidence limits are used to examine future model scenario projections for consideration of potential ecosystem changes. The future scenarios examined are the representative concentration pathways rcp4.5 and rcp8.5. Our study suggests that by the end of the twenty-first century under rcp4.5 and/or rcp8.5 that there will be average increases in sea surface temperature, surface chlorophyll a, integrated primary production and iron, average decreases in surface nitrate, phosphate and silicate, and relatively large decreases in the depth of the seasonal thermocline and percentage coverage by sea ice in the Ross Sea.

Chert and silicified wood from the Permian through Cretaceous of Antarctica contain abundant information on fungal diversity and plant–fungal interactions. The chert deposits represent a particularly interesting setting for the study of plant–fungal interactions because they preserve remains of distinctive high latitude forest ecosystems with polar light regimes that underwent a profound climate change from icehouse to greenhouse conditions. Moreover, some of the cherts and wood show the predominance of extinct groups of seed plants (e.g. Glossopteridales, Corystospermales). Over the past 30 years, documentation of fossil fungi from Antarctica has shifted from a by-product of plant descriptive studies to a focused research effort. This paper critically reviews the published record of fungi and fungal associations and interactions in the late Palaeozoic and Mesozoic cherts and silicified wood from Antarctica; certain fungal palynomorphs and fungal remains associated with adpression fossils and cuticles are also considered. Evidence of mutualistic (mycorrhizal), parasitic and saprotrophic fungi associated with plant roots, stems, leaves and reproductive organs is presented, together with fungi occurring within the peat matrix and animal–fungus interactions. Special attention is paid to the morphology of the fungi, their systematic position and features that can be used to infer fungal nutritional modes.

The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.

The origin and nature of seal carcasses scattered around the Ulu Peninsula, James Ross Island, is examined using robust and novel multidisciplinary analysis. Spatial distribution analysis indicates their predominance at low elevations and on surfaces with negligible slope. The seals died throughout the last century. Dental cement increments indicate that the seals died in late winter, and we interpret this to show an influence of the persistence and break-up of sea ice and the appearance of pools/cracks in the northern Prince Gustav Channel on death. Specifically, after being trapped by a late winter freeze-up the seals search for open water, become disoriented by snow-covered flat valleys and move inland. Carcasses from all age groups of crabeater seal are found on land, but inland movement is less notable for Weddell and leopard seals. Although most carcasses appear to have remained unchanged during the last 10 years due to the cold and dry conditions, a few carcasses that are located in sites of snow accumulation and subsequent melting have undergone enhanced decay. Decaying seal carcasses represent loci of nutrient release in a nutrient deficient environment and are colonized by algae, cyanobacteria, lichens and mosses. This research suggests further useful studies for the future.

Mount Erebus is the most active volcano on the Antarctic continent, and it has the most geographically and physically isolated geothermal soil on Earth. Preliminary genetic analysis of the microbial community present in the 65°C subsurface soil of Tramway Ridge, on Mount Erebus, revealed a unique high temperature ecosystem, with the dominant members possessing little genetic similarity to known bacteria. This study investigated the metabolism and physiology of this intriguing ecosystem using physical-chemical soil surveying, community-based phenotypic arrays, nutritional enrichment experiments and pyrosequencing. Results have provided new insights into the metabolic requirements and putative roles of specific organisms, as well as the significance of specific carbon and nitrogen sources. In enrichment experiments bicarbonate slowed down an otherwise dramatic shift in community structure. This suggests that bicarbonate maintains the native community in vitro by supplying an essential inorganic compound that is utilized for slow, autotrophic growth. This approach shows potential as a model for future investigations of cultivation resistant thermophilic communities.

House mice (Mus musculus L.) were introduced to sub-Antarctic Marion Island more than two centuries ago, and have been the only introduced mammal on the island since 1991 when feral cats were eradicated. The first mouse-injured wandering albatross (Diomedea exulans L.) chick was found in 2003 and since then attacks have continued at a low level affecting <1% of the population. In 2009, the first ‘scalpings’ were detected; sooty albatross (Phoebetria fusca Hilsenberg) fledglings were found with raw wounds on the nape. In 2015, mice attacked large chicks of all three albatross species that fledge in autumn: grey-headed (Thalassarche chrysostoma Forster) (at least 102 wounded chicks; 4.6% of fledglings), sooty (n=45, 4.3%) and light-mantled albatross (P. palpebrata Forster) (n=1, 4%). Filming at night confirmed that mice were responsible for wounds. Attacks started independently in small pockets all around the island’s 70 km coastline, separated by distances hundreds of times greater than mouse home ranges. The widespread nature of mouse attacks in 2015 on large, well-feathered chicks is alarming and highlights not only Marion Island as a priority island for mouse eradication but also that mice alone may significantly affect threatened seabird species.

Traits of primary producers associated with tissue quality are commonly assumed to have strong control over higher trophic levels. However, this view is largely based on studies of vascular plants, and cryptogamic vegetation has received far less attention. In this study natural gradients in nutrient concentrations in cryptogams associated with the proximity of penguin colonies on a Maritime Antarctic island were utilized to quantify the impact of nitrogen content on micro-arthropod communities. Proximity to penguin colonies increased the nitrogen concentration of cryptogams, and the penguin source was confirmed by decreasing δ15N values at greater distances from colonies. Micro-arthropod abundance, diversity (H’) and richness declined with distance from the penguin colonies, and was positively correlated with the nitrogen concentrations of cryptogams. Δ15N of micro-arthropods was positively correlated (r2=0.865, P<0.01) with δ15N of the moss Andreaea depressinervis indicating that penguin-derived nitrogen moves through Antarctic food webs across multiple trophic levels. Nitrogen content of cryptogams was correlated with associated micro-arthropods indicating that biotic interactions affect community development in Antarctic terrestrial ecosystems. The spatial patterns of Antarctic biodiversity can therefore be affected by local factors, such as marine vertebrates, beyond existing latitudinal patterns of temperature and water availability.

Summer iron (Fe) fertilization in the Ross Sea has previously been observed in association with diatom productivity, lithogenic particles and excess Fe in the water column. This productivity event occurred during an early breakout of sea ice via katabatic winds, suggesting that aeolian dust could be an important source of lithogenic Fe required for diatom growth in the Ross Sea. Here we investigate the provenance of size-selected dust deposited on sea ice in McMurdo Sound, south-western (SW) Ross Sea. The isotopic signature of McMurdo Sound dust (0.70533<87Sr/86Sr<0.70915 and -1.1<εNd(0)<3.45) confirms that dust is locally sourced from the McMurdo Sound debris bands and comprises a two-component mixture of McMurdo Volcanic Group and southern Victoria Land lithologies. In addition, the provenance of lithogenic sediment trapped in the water column was investigated, and the isotopic signature (εNd(0)=3.9, 87Sr/86Sr=0.70434) is differentiated from long-range transported dust originating from South America and Australia. Elevated lithogenic accumulation rates in deeper sediment traps in the Ross Sea suggest that sinking particles in the water column cannot simply result from dust input at the surface. This discrepancy can be best explained by significant upwelling and remobilization of lithogenic Fe from the sea floor.

The Antarctic Treaty System requires that the effects of potential human disturbance be evaluated, such as through the development and evaluation of Initial and Comprehensive Environmental Evaluations (IEEs and CEEs), and through the implementation of Management Plans for Antarctic Specially Protected Areas (ASPAs) and Antarctic Specially Managed Areas (ASMAs). The effectiveness of these management processes hinges on the quality and transparency of the data presented, particularly because independent validation is often difficult or impossible due to the financial and logistical challenges of working in the Antarctic. In a review of these documents and their treatment of wildlife survey data, we find that the basic elements of best data practices are often not followed; biological data are often uncited or out-of-date and rarely include estimates of uncertainty that would allow any subsequent changes in the distribution or abundance of wildlife to be rigorously assessed. We propose a set of data management and use standards for Antarctic biological data to improve the transparency and quality of these evaluations and to facilitate improved assessment of both immediate and long-term impacts of human activities in the Antarctic.

Antifreeze glycoprotein (AFGP) in Antarctic notothenioids presumably evolved once at the base of the notothenioid radiation in the Southern Ocean. Some species closely related to the endemic Antarctic notothenioids occur in non-freezing sub-Antarctic waters where antifreeze protection is unnecessary. We examined the antifreeze trait (phenotype and genotype) of these sub-Antarctic species to help infer their evolutionary history and origin. The status of the AFGP genotype (AFGP coding sequences in DNA) and/or phenotype (serum thermal hysteresis) varies widely, from being undetectable in Dissostichus eleginoides and Patagonotothen species from the Falkland Islands, minimal in Marion Island Paranotothenia magellanica and Lepidonotothen squamifrons from the South Sandwich and Bouvet islands, to considerable genotype in the Falkland Islands Champsocephalus esox and Marion Island Harpagifer georgianus. All low Antarctic notothenioid species examined show substantial AFGP trait. Mapping of the AFGP trait status onto ND2 phylogenetic trees of a large sampling of notothenioids revealed that AFGP trait reduction or loss occurred at least three independent times in different lineages.

The study of foraging success in marine predators is complicated by a lack of direct observations and relies mostly on proxy measures of foraging success. This study assessed spatial and temporal patterns of changes in body condition of southern elephant seals (Mirounga leonina) from Marion Island, based on changes in drift rates (which are related to gains and losses of blubber). Seals showed substantial individual variation in condition changes throughout migrations, which was not explained by age-, sex- or reproductive stages. Substantial variation was also evident in the spatial patterns of condition changes, although an area south of the Antarctic Polar Front (APF) between 10°E and 35°E was evidently associated with moderate, yet consistent gains in condition. Seals that foraged more distantly from Marion Island displayed more extreme gains and losses in condition, suggesting a possible risk/reward trade-off associated with foraging further afield versus closer to the island. Increased condition was consistently negatively related to sea surface temperature, suggesting that seals were generally improving their condition faster in cooler water masses. These results support previous studies predicting that continued warming of the Southern Ocean will result in changes to the habitat use patterns exhibited by southern elephant seals at sea.

The Patagonian toothfish, Dissostichus eleginoides, is a valuable fishery species and has a discontinuous distribution across the Southern Ocean. Identification of the genetic stock structure of toothfish would allow evaluation of the suitability of the spatial scale at which fisheries management operates. Genetic subdivision seems likely given the species distribution. Population genetics studies of this species have been performed; however, they have been limited by sample size, spatial coverage and/or the type of markers investigated. As a potential solution, we developed methods for extracting toothfish DNA from otoliths that are available in large numbers from collections held at several research institutes. Genetic differentiation between the three oceanic sectors was investigated. Four mitochondrial and four nuclear markers with multiple single nucleotide polymorphisms were sequenced by high throughput sequencing for samples from six locations. Genetic differentiation was found between three sectors with nuclear markers. However, only the Pacific sector was differentiated from other sectors with mitochondrial markers. This study demonstrates the usefulness of otolith DNA as a means of increasing sample sizes for population genetics research of fish. Additionally, the combination of nuclear and mitochondrial markers may allow insight into how the observed differences in movements between male and female toothfish impact population structure.

An actinobacterial strain with antimicrobial activity, INACH3013, was isolated from soil collected from Antarctica. The taxonomic status of the isolate was established using a polyphasic approach. The strain was identified as belonging to the genus Streptomyces based on the scanning electron microscopic observation and partial 16S rRNA gene sequence analysis. The sequence analysis revealed that strain INACH3013 is closely related to Streptomyces fildesensis (99.8%), S. beijiangensis (98.1%) and S. purpureus (97.2%). A phylogenetic tree constructed using the partial 16S rRNA gene sequences of strain INACH3013 and closely related strains revealed that INACH3013 fell into the same subclade as S. fildesensis and S. purpureus. Strain INACH3013 was observed to be psychrotolerant, slightly halotolerant (up to 5% NaCl) and capable of inhibiting the growth of seven Gram-negative and eight Gram-positive foodborne pathogens. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of the strain is KJ624755.

Knowledge regarding interactions between predators and their prey is fundamental for understanding underlying links between climate change and ecosystem responses, including predator demographics, in the Southern Ocean. This study reports data on reproductive performance, total population size and diet composition for macaroni and chinstrap penguins breeding at Nyrøysa on Bouvetøya during the summers of 1996–97, 1998–99, 2000–01 and 2007–08. The breeding populations of these two species at Nyrøysa decreased significantly over the study period, with an 80% decline for chinstraps and a 50% decline for macaroni penguins, despite relatively high levels of chick production. During this period macaroni penguins at this site ate a diverse diet, dominated by myctophid fish and two krill species, whereas chinstrap penguins were Antarctic krill specialists. The population changes are probably primarily due to the expanding Antarctic fur seal population, and also to landslides that are the result of increased melting on the island which have destroyed penguin breeding sites. Additional impacts from global warming of the ocean might also be playing a role and could exacerbate the decline in these penguin populations if krill and other prey are negatively impacted in the future in this region. The local chinstrap penguin population would probably be most heavily affected given its narrow feeding niche and small current population size.