Ophiuroids are a conspicuous and often dominant component of the Antarctic continental shelf benthos. Here we report on the ophiuroids collected from the Burdwood Bank, off the Patagonian Shelf, through the shallow water areas of the Scotia Arc, down the west Antarctic Peninsula and as far south as Pine Island Bay in the eastern Amundsen Sea. This preliminary and primarily pattern based study identifies some regional differences in assemblages and highlights the role of the Antarctic Circumpolar Current as a barrier, as well as a facilitator, to dispersal. In order to effectively compare between studies we highlight the need for accurate, expert taxonomic identification of specimens.

Nineteen specimens of the rare dragonfish Vomeridens infuscipinnis were evaluated for meristic counts, morphometric measurements, vomerine teeth and the supratemporal canal, anatomical and histological observations of bone, cartilage and lipid, diet, and reproductive status. Seven individuals were measured for buoyancy. All specimens had small vomerine teeth that varied in number. There was also variability in the arrangement of the supratemporal pores and canals. Vomeridens possess a body with little bone and considerable amounts of cartilage and lipid. A mean percentage buoyancy of 1.61% indicated that Vomeridens is nearly neutrally buoyant. Inferences from measurements of buoyancy and from morphological data suggest that Vomeridens lives in an epibenthic water column habitat at 400–900 m. Facilitated by its reduced body density, Vomeridens are likely to forage in the water column by hovering above the substrate. The stomach contents consisted of krill (Euphausia superba), some as large as 46–50 mm.The absolute and relative fecundity in seven female was 1576–2296 oocytes (mean 1889) and 21.3–28.9 oocytes g-1 body weight (mean 25.3), respectively. The reproductive effort in terms of egg diameter, GSI, and absolute and relative fecundity is similar to that for other bathydraconids.

Despite the general view that the Antarctic intertidal conditions are too extreme to support obvious signs of macrofaunal life, recent studies have shown that intertidal communities can survive over annual cycles. The current study investigates distribution of taxa within a boulder cobble matrix, beneath the outer, scoured surface of the intertidal zone at Adelaide Island, west Antarctic Peninsula. The intertidal zone at the study sites comprised compacted, flattened cobble pavements, which have been shown to be highly stable over time. Community structure was investigated using univariate and multivariate approaches. Virtually no macrofauna were present on the outer surface, but richness, diversity, abundance and size of animals increased with depth into the rock matrix. Abundance of taxa increased by an order of magnitude between the outer surface and the lowest level sampled. These findings show that the Antarctic intertidal is not always the uninhabitable environment currently perceived, and that under these highly variable environmental conditions at least some species have the capacity to survive.

For land-breeding marine organisms such as seabirds, knowledge about their habitat use has mainly been gained through studies of breeding individuals that are constrained to return frequently to their breeding grounds. In this study we set out to measure whether: a) habitat selection in the non-breeding period predicts habitat selection in the breeding period, and b) whether breeding individuals concentrated their activity on the closest suitable habitats. Macaroni Eudyptes chrysolophus and gentoo Pygoscelis papua penguins, two marine predators with contrasting foraging strategies, were tracked from the Iles Kerguelen and their habitat selection investigated through Mahalanobis distances factorial analysis. This study presents the first data about gentoo penguins’ juvenile dispersal. For both species, results showed 6.9 times larger maximum ranges and up to 12.2 times greater distances travelled during the non-breeding period. Habitat suitability maps suggested both species made similar environmental selections whatever the period. Macaroni penguins targeted pelagic areas beyond the shelf break while gentoo penguins always remained over the shelf. We consider the ecological significance of larger scale movements made outside the breeding period and suggest that this non-breeding period is of particular interest when attempting to understand an animal's habitat selection.

This study examined high temperature survival and heat shock protein 70 (Hsp70) responses to temperature variation for two marine invertebrate species on sub-Antarctic Marion Island. The isopod Exosphaeroma gigas Leach and the amphipod Hyale hirtipalma Dana had the same tolerance to high temperature. The mean upper temperature which was lethal for 50% of the population (upper lethal temperature, ULT50) was 26.4°C for both species. However, the isopod E. gigas showed significant plasticity of ULT50, with a positive response to acclimation. In addition, the isopod had a heat shock response of Hsp70 at all acclimations, and the amount of Hsp70 protein increased significantly from basal levels upon an acute warm exposure after a cold acclimation. By contrast, the amphipod H. hirtipalma showed limited plasticity of ULT50 and no evidence for a heat shock response (failure of three different Hsp70 antibodies to bind to the extracted 70kDa proteins). Overall, these results reflect different flexibility of thermal tolerance of intertidal invertebrate species on Marion Island, with possible variation in the underlying cellular mechanisms, suggesting that warming associated with climate change may result in changes in species assemblage structure in sub-polar environments.

This is the first study to examine the tolerance of Antarctic springtails (Collembola) to ultraviolet radiation (UV). Survival of extended attenuated exposure to sunlight was examined for both individuals and aggregations of the species Gomphiocephalus hodgsoni Carpenter over a 10 day period. Both individuals and aggregations demonstrated significantly higher survival and moult rates from control treatments kept in the dark to those exposed to UV. A photo-inhibitive element to moulting is indicated that may function to protect post-ecdysial springtails when their emergent cuticles are more sensitive to the external environment. DNA damage was measured in springtails directly exposed to sunlight for 5 h on a clear sunny day. Significant differences were found between treated animals and controls kept in the dark. There was some reduction of damage 12 and 24 h after exposure, when springtails had been placed in the dark to recover. This indicates the up-regulation of DNA repair mechanisms, with the 12 h treatment in particular showing no significant difference with controls. In addition to providing a first look at UV tolerance in these soil arthropods, these findings recommend employing strict protocols for collections of sample material for subsequent biological analysis in order to minimize the interactive effects of photo-damage.

We investigated the physiology of two closely related albatross species relative to their breeding strategy: black-browed albatrosses (Thalassarche melanophris) breed annually, while grey-headed albatrosses (T. chrysostoma) breed biennially. From observations of breeding fate and blood samples collected at the end of breeding in one season and feather corticosterone levels (fCort) sampled at the beginning of the next breeding season, we found that in both species some post-breeding physiological parameters differed according to breeding outcome (successful, failed, deferred). Correlations between post-breeding physiology and fCort, and links to future breeding decisions, were examined. In black-browed albatrosses, post-breeding physiology and fCort were not significantly correlated, but fCort independently predicted breeding decision the next year, which we interpret as a possible migratory carry-over effect. In grey-headed albatrosses, post-breeding triglyceride levels were negatively correlated with fCort, but only in females, which we interpret as a potential cost of reproduction. However, this potential cost did not carry-over to future breeding in the grey-headed albatrosses. None of the variables predicted future breeding decisions. We suggest that biennial breeding in the grey-headed albatrosses may have evolved as a strategy to buffer against the apparent susceptibility of females to negative physiological costs of reproduction. Future studies are needed to confirm this.

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 (r 2=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.

Rapid and regionally contrasting climate changes have been observed around Antarctica. However, our understanding of the impact of these changes on ecosystems remains limited, and there is an urgent need to better identify habitats of Antarctic species. The Weddell seal (Leptonychotes weddellii) is a circumpolar mesopredator and an indicative species of Antarctic marine communities. It has been extensively studied in the western Ross Sea and East Antarctica, and an understanding of its ecology in the Weddell Sea in the wintertime is emerging. We documented the behavioural response(s) of four Weddell seals from February to June in 2017 in the Filchner-Ronne Ice Shelf region and related these to unusual oceanographic conditions in 2017. Unexpectedly, we found that Weddell seals had the longest foraging effort within the outflow of Ice Shelf Water or at its turbulent boundary. They also foraged on the eastern side of the trough from April to June within the Modified Warm Deep Water and seem to take advantage of the unusual conditions of persistent inflow of warm waters through the winter. Linking animal behavioural responses to oceanographic conditions is informative for quantifying rarely recorded events and provides great insight into how predators may respond to changing conditions.

Wide-ranging, surface-feeding pelagic seabirds are the most numerous functional group of birds in the Southern Ocean. The mesoscale habitat use of these birds is increasingly being quantified by relating their movements to remotely sensed, near surface properties of the ocean. However, prey availability at the sea surface may also be determined by habitat characteristics not measurable from space. For instance, benthic-pelagic coupling, which occurs when seabed processes affect productivity in the epipelagic zone, can link benthic habitat type to availability of surface prey. We combined acoustically derived maps of the substrate of the South Georgia shelf with GPS tracking to quantify the sub-mesoscale habitat use of breeding black-browed albatrosses. We show that albatrosses preferentially used waters overlaying glacial moraine banks near the shelf edge and that this was unrelated to the presence of trawlers targeting mackerel icefish, which are also associated with these features. Stomach temperature profiles suggest that albatrosses primarily caught krill and fish over the banks. We hypothesize that black-browed albatrosses target waters overlaying moraine banks due to upward benthic-pelagic coupling, mediated by an increase in abundance of zooplankton such as Antarctic krill. Our findings suggest that the potential effects of such processes on pelagic seabird distribution warrant wider investigation.

Meroplankton community studies in the Antarctic have primarily focused on the coastal waters of both the Antarctic Peninsula and the Ross Sea. The New Zealand International Polar Year - Census of Antarctic Marine Life (IPY-CAML) voyage to the Ross Sea during the late summer (February–March) 2008 provided the first meroplankton samples from three regions in the deep, oceanic waters of the Ross Sea (shelf, slope and adjacent offshore Antarctic waters of Admiralty Seamount and Scott Island). We used a combined morphological and molecular approach to identify 36 larval operational taxonomic units based on sequences from three loci (16S, 18S, COI), and exclude early developmental stages of holoplankton. Overall, larval abundance was lower than previous Antarctic studies (5.19 specimens per 100 m3), with larvae most abundant in the first 200 m of the water column and most diverse in the shelf region. Multivariate analysis revealed significant differences in the meroplankton community between regions and depth ranges, but with low similarity within these groupings; differences between water masses were undetectable due to the confounding effect with both region and depth. The influence of nearby benthic populations (e.g. the acorn barnacle Bathylasma corolliforme) and/or locally abundant taxa (e.g. the nudibranch Tergipes antarcticus) was evident in the meroplankton community.

Seven community complexes have been described across sub-Antarctic Marion Island, amongst these fellfield that comprise low plant cover dominated by Azorella selago Hook. f. Azorella is considered a keystone species since it forms nutrient rich environments for microarthropod communities and epiphytic plants. Two distinct growth forms typify Azorella, namely discrete cushions and continuous mats. Whether these continuous mats normally consist of a single large cushion individual, or whether several individual plants merge, interdigitating to form a continuous area, remains unclear. As such, it is important to obtain some measure of Azorella growth dynamics before embarking on phylogeographic studies. Previous genetic studies indicated that several microarthropod species are significantly substructured across Marion Island, but it remains unclear whether similar subdivisions characterize Azorella. We used chloroplast sequence data (trnH-psbA) and amplified fragment length polymorphism (AFLP) to investigate these questions. No sequence variation characterized the trnH-psbA region in Azorella across Marion Island. In contrast, the AFLP results indicated that an A. selago mat comprises multiple individuals. We argue that mats can be formed through at least two processes namely fragmentation, where parts of the cushion plant die off creating open areas for the establishment of different individuals and/or high density of interdigitating individuals merging to form the mat. Fragment data further indicated significant substructure for Azorella across Marion Island (FST = 0.101, P = 0.01) and we attribute this to past vicariance.

Antarctic krill are the dominant metazoan in the Southern Ocean in terms of biomass; however, their wide and patchy distribution means that estimates of their biomass are still uncertain. Most currently employed methods do not sample the upper surface layers, yet historical records indicate that large surface swarms can change the water colour. Ocean colour satellites are able to measure the surface ocean synoptically and should theoretically provide a means for detecting and measuring surface krill swarms. Before we can assess the feasibility of remote detection, more must be known about the reflectance spectra of krill. Here, we measure the reflectance spectral signature of Antarctic krill collected in situ from the Scotia Sea and compare it to that of in situ water. Using a spectroradiometer, we measure a strong absorption feature between 500 and 550 nm, which corresponds to the pigment astaxanthin, and high reflectance in the 600–700 nm range due to the krill's red colouration. We find that the spectra of seawater containing krill is significantly different from seawater only. We conclude that it is tractable to detect high-density swarms of krill remotely using platforms such as optical satellites and unmanned aerial vehicles, and further steps to carry out ground-truthing campaigns are now warranted.

Adélie penguins (Pygoscelis adeliae) are responding to ocean–climate variability throughout the marine ecosystem of the western Antarctic Peninsula (WAP) where some breeding colonies have declined by 80%. Nuclear and mitochondrial DNA (mtDNA) markers were used to understand historical population genetic structure and gene flow given relatively recent and continuing reductions in sea ice habitats and changes in numbers of breeding adults at colonies throughout the WAP. Genetic diversity, spatial genetic structure, genetic signatures of fluctuations in population demography and gene flow were assessed in four regional Adélie penguin colonies. The analyses indicated little genetic structure overall based on bi-parentally inherited microsatellite markers (F ST =-0.006–0.004). No significant variance was observed in overall haplotype frequency (mtDNA Φ ST =0.017; P=0.112). Some comparisons with Charcot Island were significant, suggestive of female-biased philopatry. Estimates of gene flow based on a two-population coalescent model were asymmetrical from the species’ regional core to its northern range. Breeding Adélie penguins of the WAP are a panmictic population and hold adequate genetic diversity and dispersal capacity to be resilient to environmental change.

Despite their pivotal role as primary producers, there is little information as to the diversity and physiology of cyanobacteria in the meltwater ecosystems of polar regions. Thirty cyanobacterial mats from Adelaide Island, Antarctica were investigated using 16S rRNA gene pyrosequencing and automated ribosomal intergenic spacer analysis, and screened for cyanobacterial toxins using molecular and chemical approaches. A total of 274 operational taxonomic units (OTUs) were detected. The richness ranged between 8 and 33 cyanobacterial OTUs per sample, reflecting a high mat diversity. Leptolyngbya and Phormidium (c. 55% and 37% of the OTUs per mat) were dominant. Cyanobacterial community composition was similar between mats, particularly those obtained from closely adjacent locations. The cyanotoxin microcystin was detected in 26 of 27 mats (10–300 ng g-1 organic mass), while cylindrospermopsin, detected for the first time in Antarctica, was present in 21 of 30 mats (2–156 ng g-1 organic mass). The latter was confirmed via liquid chromatography-mass spectrometry and by the presence of the cyrAB and cyrJ genes. This study demonstrates the usefulness of pyrosequencing for characterizing diverse cyanobacterial communities, and confirms that cyanobacteria from extreme environments produce a similar range of cyanotoxins as their temperate counterparts.