A dramatic reduction in catch rates of Antarctic toothfish in McMurdo Sound, Antarctica, has led to conclusions that the commercial bottom longline fishery for toothfish in the Ross Sea has drastically altered the toothfish population with cascading effects on the McMurdo Sound ecosystem. However, results from a new monitoring programme for Antarctic toothfish and other top predators carried out in McMurdo Sound in 2014 have shown toothfish catch rate, fish size and fish age similar to those observed prior to 2002. These results suggest that either large and old fish have returned to McMurdo Sound following a temporary environmentally driven absence or that they remained locally present but were not detected in the areas sampled. These findings highlight the importance of continued standardized monitoring for detecting the potential effects of fishing on the Ross Sea ecosystem.

The arrival of iceberg B09B in Commonwealth Bay, East Antarctica, and subsequent fast ice expansion has dramatically increased the distance Adélie penguins (Pygoscelis adeliae) breeding at Cape Denison must travel in search of food. This has provided a natural experiment to investigate the impact of iceberg stranding events and sea ice expansion along the East Antarctic coast. As part of the Australasian Antarctic Expedition 2013–14, the Adélie penguin colony at Cape Denison was censused to compare to historic counts. Whilst some 5520 pairs still bred at Cape Denison there has been an order of magnitude decline in Adélie numbers in the area in comparison to the first counts a century ago and, critically, recent estimates based on satellite images and a census in 1997. In contrast, an Adélie population on the eastern fringe of Commonwealth Bay just 8 km from the fast ice edge was thriving, indicating the arrival of B09B and fast ice expansion was probably responsible for the observed recent population decline. In conclusion, the Cape Denison population could be extirpated within 20 years unless B09B relocates or the now perennial fast ice within the bay breaks out. Our results have important implications for wider East Antarctic if the current increasing sea ice trend continues.

Mineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2 s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.

In this paper we report the first characterization of cultivable bacteria obtained from the Antarctic sea urchin Sterechinus neumayeri. The coelomic fluid was obtained from a pool of sea urchins which was plated onto different media to isolate the bacteria. A total of 42 isolates of psychrotrophic and aerobic γ-Proteobacteria (59.5%), Flavobacteria (33.3%) and Actinomycetes (7.2%) were isolated and sequenced. These bacteria were exposed to heavy metals and antibiotics, where 38 strains were analysed by the minimal inhibitory concentration method. Antibiotic resistance was detected in 44% of cultivable strains, and a further 13% presented co-resistance to antibiotics and heavy metals. The genera of bacteria that showed an increased resistance and co-resistance to metals and antibiotics were Flavobacterium, Psychrobacter and Pseudomonas. Additionally, 30.9% of isolated bacterial strains contained plasmids, which are probably related to resistance and co-resistance to metals. These results indicate that sea urchin-associated bacteria could be reservoirs for antibiotic resistance genes.

Large floods bringing significant sediments into the coastal oceans have not been observed in Antarctica. We report evidence of a large flood event depositing over 50 cm of sediment onto the nearshore benthic habitat at Salmon Bay, Antarctica, between 1990 and 2010. Besides direct observations of the sedimentation, the evidence involves a debris flow covering old tyre tracks from the early 1960s, as well as evidence of a considerable amount of sediment transported onto the Salmon Creek delta. We believe that the flood was sourced from the Salmon Glacier and possibly the smaller Blackwelder Glacier. Such floods will be more common in the future and it is important to better understand their ecological impacts with good monitoring programmes.

We extend a previous analysis of Antarctic tour ship vessel traffic to include 20 years of commercial cruise activity (1993/94–2012/13) using recently digitized historical records and new data on vessel landings since 2008/09. Using tourism statistics from 1989/90–2013/14, we also examine trends in passenger numbers, landings and the nationalities of passengers travelling to the Antarctic Peninsula region. This study represents the most comprehensive long-term perspective on how tour ship activity has changed spatially and temporally over a period in which visitation has grown ten-fold. Passenger landings and marine traffic are highly concentrated at a few specific locations, particularly along the Peninsula’s south-western coast. Antarctic tourism activity is closely correlated with measures of economic activity in those countries contributing the largest numbers of visitors to the region. The nationalities of Antarctic tourists have shifted over the years, particularly with respect to an increasing number of visitors from China. Since emerging markets for Antarctic travel are probably far from saturated, interest in travelling to Antarctica will probably continue to grow. Understanding visitation patterns will focus efforts to monitor potential anthropogenic impacts and inform management decisions regarding activities in and around the Antarctic region.

On sub-Antarctic Marion Island, wandering albatross (Diomedea exulans) nests support high abundances of tineid moth, Pringleophaga marioni, caterpillars. Previous work proposed that the birds serve as thermal ecosystem engineers by elevating nest temperatures relative to ambient, thereby promoting growth and survival of the caterpillars. However, only 17 days of temperature data were presented previously, despite year-long nest occupation by birds. Previous sampling was also restricted to old and recently failed nests, though nests from which chicks have recently fledged are key to understanding how the engineering effect is realized. Here we build on previous work by providing nest temperature data for a full year and by sampling all three nest types. For the full duration of nest occupancy, temperatures within occupied nests are significantly higher, consistently by c. 7°C, than those in surrounding soils and abandoned nests, declining noticeably when chicks fledge. Caterpillar abundance is significantly higher in new nests compared to nests from which chicks have fledged, which in turn have higher caterpillar abundances than old nests. Combined with recent information on the life history of P. marioni, our data suggest that caterpillars are incidentally added to the nests during nest construction, and subsequently benefit from an engineering effect.

Lipid biomarkers are potential tools for identifying the sources, diagenesis and reactivity of organic matter (OM) in marine systems, including in Antarctica where the particular environmental characteristics have motivated several studies of organic markers. Sedimentary sterol distributions were determined in two sediment cores (PGI-1 and PGI-2) collected from the marine environment around Penguin Island, Antarctica, during the 2007–08 summer. The cores were sectioned at 1 cm intervals and the sterols were analysed using gas chromatography with flame ionization detection. The results indicate that the sterols were subjected to decades of degradation and transformation with depth in both cores. However, an expected progressive conversion of stenols to stanols (evaluated by 5α-stanols/Δ5-stenols ratio) within the deepest sediment layers was not clear, suggesting low degradation rates. In PGI-1, the deposition of large quantities of penguin guano affected the distribution of sterols and, consequently, primary production was favoured by the ornithogenic soil input. The results contribute to the understanding of the current processes associated with primary sources and transformation of OM in this important region of the Antarctic environment.

Any future changes in the volume of Antarctica’s ice sheets will depend on the dynamic response of outlet glaciers to shifts in environmental conditions. In the Transantarctic Mountains, this response is probably heavily dependent on the geometry of the system, but few studies have quantified the sensitivity of these glaciers to environmental forcings. Here we investigated the controls, along-flow sensitivity and time-dependent dynamics of Skelton Glacier. Three key outcomes were: i) present-day flow is governed primarily by surface slope, which responds to reduced valley width and large bed undulations, ii) Skelton Glacier is more susceptible to changes in atmospheric temperature than precipitation through its effect on basal sliding near the grounding line, and iii) under conditions representative of Pliocene and Quaternary climates large changes in ice thickness and velocity would have occurred in the lower reaches of the glacier. Based on these new quantitative predictions of the past and present dynamics of Skelton Glacier, we suggest that similar Transantarctic Mountain outlet glaciers could experience greater ice loss in their confined, lower reaches through increased basal sliding and ocean melt under warmer-than-present conditions. These effects are greatest where overdeepenings exist near the grounding line.

To date, many studies surveying the bacterial communities in lichen thalli from diverse geographical areas have shown that Alphaproteobacteria is the predominant bacterial class in most lichens. In this study, bacterial communities in several Antarctic lichens with different growth form and substrates were analysed. The bacterial community composition in fruticose and foliose lichens, Cladonia, Umbilicaria and Usnea, and crustose lichens, Buelia granulosa, Amandinea coniops and Ochrolechia parella, from King George Island was analysed by pyrosequencing of bacterial 16S rRNA genes. Results showed that Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were predominant phyla. The predominant bacterial class in most of the samples was Alphaproteobacteria. Acetobacteriaceae of the order Rhodospiralles in Alphaproteobacteria was the most abundant bacterial family in Antarctic lichens. The LAR1 lineage of the order Rhizobiales, a putative N-fixer which has been frequently observed in lichens from temperate areas, was detected only from a few samples at low frequency. It is expected that other bacterial taxa are working as N-fixers in Antarctic lichens. From the PCoA analysis of the Fast UniFrac distance matrix, it was proposed that the microbial community structures in Antarctic lichens were affected by host species, growth form and substrates.

An experiment applying controlled meteorological (CMET) balloons near the coast of Dronning Maud Land, Antarctica, in January 2013 is described. Two balloons were airborne for 60 and 106 hours with trajectory lengths of 885.8 km and 2367.4 km, respectively. The balloons carried out multiple controlled soundings on the atmospheric pressure, temperature and humidity up to 3.3 km. Wind speed and direction were derived from the balloon drift. Observations were compared with radiosonde sounding profiles from the Halley Research Station, and applied in evaluating simulations carried out with the weather research and forecasting (WRF) mesoscale atmospheric model. The most interesting feature detected by the CMET balloons was a mesoscale anticyclone over the Weddell Sea and the coastal zone, which was reproduced by the WRF model with reduced intensity. The modelled wind speed was up to 10 m s-1 slower and the relative humidity was 20–40% higher than the observed values. However, over the study period the WRF results generally agreed with the observations. The results suggest that CMET balloons could be an interesting supplement to Antarctic atmospheric observations, particularly in the free troposphere.

Data on grain size and heavy mineral composition for surface sediments on the Prydz Bay continental shelf was analysed to identify sediment features and provenance. The grain size composition of surface sediments indicate spatial variations in the glaciomarine environment and the key factors influencing sedimentation, which on the shelf include topography/water depth, currents and icebergs. The study area was divided into two sections by Q-type factor analysis: section I included Prydz Channel, Amery Basin and Svenner Channel, and section II included Four Ladies Bank, Fram Bank and the area in front of the Amery Ice Shelf. Sedimentation in section I is mainly controlled by currents and topography/water depth. However, in section II, icebergs/floating ice masses, the Amery Ice Shelf and currents have prominent effects on sedimentation. The heavy mineral composition indicates that surface sediments on the eastern side of the bay, including Four Ladies Bank, are primarily derived from Princess Elizabeth Land. Sediments in the area in front of the Amery Ice Shelf, Svenner Channel, Amery Basin and Prydz Channel have a mixed source from the eastern regions around the bay, including the Prince Charles Mountains and Princess Elizabeth Land. The contribution from Mac. Robertson Land to sediment at Fram Bank is limited.

Polinices marambioensis is a naticid gastropod which is the most common constituent in fossil accumulations in the upper section of the Cucullaea I Allomember (Middle Eocene) of the La Meseta Formation in James Ross Basin, Antarctic Peninsula. This species was an important predator of infaunal bivalves and gastropods, including other naticids. The aim of this work was to assess the pattern of predation and cannibalistic behaviour of P. marambioensis. A total of 2648 specimens of P. marambioensis were examined for drill holes, which were assigned to Oichnus paraboloides. Drilling frequency data were measured as a proxy for predation intensity and statistical analyses were performed. Further, the site of each drill hole was established according to the morphological features of the shell on each specimen to assess possible preference of predators for the site of perforation. Results suggest that P. marambioensis is an efficient cannibalistic predator for a specific size range of prey (8–22 mm), and drill holes are distributed preferentially in two specific sectors of their shells. This selective cannibalistic prey behaviour in P. marambioensis affected not only the dynamics of their populations but the ecological structure of the community in which they lived.

The Antarctic fish fauna from outer continental shelf/upper slope depths is under-sampled compared to that of the inner shelf, and there are limited quantitative data available on absolute abundance and taxonomic change with depth. A photographic survey of demersal fishes was conducted along a depth-gradient of 400–2099 m on the outer shelf and upper slope west of Anvers Island, Palmer Archipelago. A total of 1490 fishes were identified at least to the family level. Notothenioids composed 52.7% of absolute abundance and non-notothenioids 47.3%. The most abundant families were Nototheniidae (39.4%), followed by Macrouridae (28.9%), Zoarcidae (16.9%), and Channichthyidae (12.1%). The most abundant species were the notothenioids Lepidonotothen squamifrons (30.5%) and Chionobathyscus dewitti (11.7%), and the non-notothenioid Macrourus spp. (29.5%). The absolute abundance of all fishes peaked at 400–599 m. Depths of maximum abundance were 400–599 m for L. squamifrons, 700–1499 m for Macrourus spp., and 900–1499 for C. dewitti. At 700–999 m the abundance shifted from primarily notothenioids to the non-notothenioids Macrourus spp. and zoarcids. Fishes of the outer shelf and upper slope are not provincialized like those of the inner shelf and are circum-Antarctic.

Deception Island is an active volcano located in Bransfield Strait. Its volcanic activity is linked to the presence of gravity anomalies that influence the definition of the geoid. In this paper, a precise undulation geoid model (GeoiDEC14) has been computed from GPS, gravimetric and levelling measurements. GeoiDEC14 highlights local anomalies of the island that match with hot spots, such as the minimum values shown in Fumarole Bay and Whalers Bay (fumarole areas), or the maximum values found in the remains of lava at Colatinas, Black Glacier and Murature Point. Comparison of GeoiDEC14 with global models always shows negative values due to an average of 18.80 m for our model compared to 19.80–20.60 m for models such as ITSG-Grace2014s, EGM08, AIUG-Grace03s or EGM96. This difference is due to the lack of resolution of global models and to the volcanic activity on the island. To confirm the results, the same measurements were taken on nearby Livingston Island. The values of geoid undulation on this island reaffirm the lack of detail in the global geoid in the area, presenting an average of 18.90 m, similar to the average value of GeoiDEC14.

Deschampsia antarctica Desv. (Poaceae) grows in coastal habitats in the Maritime Antarctic where it is often exposed to sea spray. Salt crystals have been observed on the surface of leaves in plants treated with high NaCl. We investigated if D. antarctica is a salt tolerant species that allows sodium ions to diffuse into the root where a salt overly sensitive (SOS) system extrudes Na+ from root cells and facilitates its movement through the xylem up to the leaves. Leaf epidermis, physiological parameters and sodium transporters in D. antarctica plants exposed to NaCl were studied over 21 days. Epidermal scanning electron microscopy showed trichome induction in the leaves of salt treated plants. In addition, salt treated plants showed increased sodium and proline levels with a concomitant increased expression of SOS genes (1 and 3). These results indicate that Na+ is taken up by the roots of D. antarctica and transported to the leaves. The sodium flux may be controlled by SOS1 activity. Up-regulation of the SOS1 gene may be involved in the increased sodium levels observed in the leaves of salt treated plants. Trichomes may also be involved in sodium exudation through the leaves under saline conditions.

The South Sandwich Islands and associated seamounts constitute the volcanic arc of an active subduction system situated in the South Atlantic. We introduce a map of the bathymetry and geological setting of the South Sandwich Islands and the associated East Scotia Ridge back-arc spreading centre that consists of two sides: side 1, a regional overview of the volcanic arc, trench and back-arc, and side 2, detailed maps of the individual islands. Side 1 displays the bathymetry at scale 1:750 000 of the intra-oceanic, largely submarine South Sandwich arc, the back-arc system and other tectonic boundaries of the subduction system. Satellite images of the islands on side 2 are at scales of 1:50 000 and 1:25 000 with contours and main volcanological features indicated. These maps are the first detailed topological and bathymetric maps of the area. The islands are entirely volcanic in origin, and most have been volcanically or fumarolically active in historic times. Many of the islands are ice-covered, and the map forms a baseline for future glaciological changes caused by volcanic activities and climate change. The back-arc spreading centre consists of nine segments, most of which have rift-like morphologies.

In the 1980s, penguins dominated the prey remains of sub-Antarctic skuas Stercorarius antarcticus breeding on Marion Island, whereas on neighbouring Prince Edward Island burrowing petrels made up >95% of prey remains in nest middens. This difference resulted at least in part from the impact of introduced cats Felis catus on Marion Island’s burrowing petrel populations. Cats were introduced to Marion Island in 1949, and prior to their eradication in 1991, they killed an estimated 450 000 petrels each year, greatly reducing the densities of petrels breeding on the island. A repeat survey of skua prey remains showed that penguins still dominated the prey of breeding sub-Antarctic skuas on Marion Island in the summer of 2010–11, two decades after cats were eradicated from the island. The proportion of penguin remains decreased slightly compared to 1987–88, but this might be expected given the decreases in penguin numbers on Marion Island over this period. Regurgitated pellets confirmed the dominance of penguin prey on Marion Island. Taken together with the decrease in skua numbers on Marion Island over the last two decades, our results suggest that there has been little recovery in the population of at least summer-breeding burrowing petrels since cats were eradicated.