A saccoderm desmid Mesotaenium berggrenii forma (Mesotaeniaceae) occurring as a major component of the snow algal flora is reported from the Windmill Islands region of Continental Antarctica. Stages of the life cycle of the species are illustrated. The local distribution of the species is outlined, habitat conditions described, taxonomy, reproduction and survival strategies discussed. Morphological and nuclear size classes indicate the possibility of polyploidy in the species.

Biological soil crusts are associations of lichens, mosses, algae, cyanobacteria, microfungi and bacteria in different proportions forming a thin veneer within the top centimetres of soil surfaces. They occur in all biomes, but particularly in arid and semi-arid regions, even in the most extreme climates. They carry out crucial ecosystem functions, such as soil stabilization, influencing water and nutrient cycles, and contribute to the formation of microniches for heterotrophic life. In continental Antarctica especially, these roles are essential because no higher plants provide such ecosystem services. We provide a detailed description of biological soil crusts from Garwood Valley, McMurdo Dry Valleys region (78°S) and Diamond Hill (80°S) in the Darwin Mountains region. The coverage was low at 3.3% and 0.8% of the soil surface. At Garwood Valley the crusts were composed of green algal lichens, cyanobacteria, several species of green algae and the moss Hennediella heimii (Hedw.) R.H. Zander. Diamond Hill crusts appear to be unique in not having any species of cyanobacteria. Major parts are embedded in the soil, and their thickness correlates with higher chlorophyll contents, higher soil organic carbon and nitrogen, which are fundamental components of this species poor cold desert zone.

In the face of climate variability and change, science in Antarctica needs to address increasingly complex questions. Individual small studies are being replaced by multinational and multidisciplinary research programmes. The Latitudinal Gradient Project (LGP) is one such approach that combines a series of smaller studies under a single broad hypothesis to provide information that uses a gradient in latitude as a surrogate for environmental gradients, particularly climate. In this way latitudinal differences can be used to indicate climate change differences. The Key Questions for the LGP were developed via national workshops in Italy, New Zealand, and the USA and via two international workshops at SCAR conferences. Science and logistics are currently jointly shared by New Zealand, Italy and the USA, and cover marine and inland ecosystem studies along the Victoria Land coast from 72° to 78°S with plans for extensions to 85°S. The LGP forms part of the SCAR Programme Evolution and Biodiversity in Antarctica. This Special Issue summarizes some of the work in the first three years of the LGP (2002–2005), between McMurdo Sound and Cape Hallett, to form a basis for future comparative studies as the research shifts along the latitudinal span in the next decade.

Bioremediation has been proposed as a means of dealing with oil spills on the continent. However, the introduction of non-native organisms, including microbes, even for this purpose would appear to breach the terms of the Environmental Protocol to the Antarctic Treaty. This study therefore aimed to optimize the growth conditions and diesel degradation activity of the Antarctic native bacteria Arthrobacter spp. strains AQ5-05 and AQ5-06 through the application of a one-factor-at-a-time (OFAT) approach. Both strains were psychrotolerant, with the optimum temperature supporting diesel degradation being 10–15°C. Both strains were also screened for biosurfactant production and biofilm formation. Their diesel degradation potential was assessed using Bushnell–Haas medium supplemented with 0.5% (v/v) diesel as the sole carbon source and determined using both gravimetric and gas chromatography and mass spectrophotometry analysis. Strain AQ5-06 achieved 37.5% diesel degradation, while strain AQ5-05 achieved 34.5% diesel degradation. Both strains produced biosurfactants and showed high biofilm adherence. Strains AQ5-05 and AQ5-06 showed high cellular hydrophobicity rates of 73.0% and 81.5%, respectively, in hexadecane, with somewhat lower values of 60.5% and 70.5%, respectively, in tetrahexadecane. Optimized conditions identified via OFAT increased diesel degradation to 41.0% and 47.5% for strains AQ5-05 and AQ5-06, respectively. Both strains also demonstrated the ability to degrade diesel in the presence of heavy metal co-pollutants. This study therefore confirms the potential use of these cold-tolerant bacterial strains in the biodegradation of diesel-polluted Antarctic soils at low environmental temperatures.

Five species of myctophid fishes were collected by trawl from the Elephant Island region of the Antarctic Peninsula between 60°30′–62°S and 55°–61°30′W. Two species, Gymnoscopelus braueri and Krefftichthyes anderssoni were lipid-rich (406–456 mg g−1 dry weight whole fish) with wax esters (WE) the major lipid class. In three species, G. opisthopterus, G. nicholsi, and Electrona carlsbergii, triacylglycerols (TAG) were the major lipid. All fish had oily bones, with values up to 471 mg g−1 dry weight in the vertebral centra of K. anderssoni. The principal fatty acids of the TAG-rich myctophids included the monoenes 18:1(n-9) and 20:1. There were lower levels of 16:0 and 18:0 saturated fatty acids. Polyunsaturated fatty acids (PUFA) were present at higher abundance in the TAG-rich E. carlsbergii and G. opisthopterus, with lower levels in G. nicholsi. In comparison, the WE-dominated species contained lower levels of PUFA than in the TAG-rich species. The principal fatty acids of the WE-rich myctophids included the monoenes 18:1(n-9), 16:1(n-7), and 18:1(n-7), with lower levels of the saturated acids 16:0 and 18:0. Fatty alcohols were dominated by 16:0 and 14:0 and the monounsaturated 18:1(n-9) with 16:1(n-7), 18:1(n-7), and 20:1(n-9). Based on the fatty acid profiles, the diet of G. opishtopterus and G. nicholsi, previously thought to be mainly Euphausia superba, is suggested to include copepods and other zooplankton with only a minor krill component, possibly consisting of other species than E. superba.

Temperature records in the Antarctic Peninsula have shown a climatic warming of 1.5°C over the past 30 years and a number of ice shelves have retreated. The most dramatic retreat has been that of Wordie Ice Shelf which has undergone a catastrophic disintegration since the 1960s. Understanding the cause and mechanism of the break-up may provide important clues to the fate of ice shelves farther south which, it has been suggested, help to stabilize the West Antarctic Ice Sheet. The break-up of Wordie Ice Shelf has been analysed using Landsat and SPOT imagery. These observations show that the relative contribution of the various input glaciers to the grounding line flux has not altered during the break-up. This means that the effect of the rapid and almost complete removal of the ice shelf has not been transmitted upstream and is not causing a rapid increase in velocities on the input glaciers. The volume of grounded ice in the catchment of Wordie Ice Shelf will thus, be largely unaffected by the break-up and there will be no significant contribution to sea level change. Since other ice shelves around the Antarctic Peninsula are also fed by relatively steep mountain glaciers the effect of the loss of the ice shelves on sea level would be likely to be similarly small.

In order to monitor the evolution of the active layer in the South Shetland Islands, in February 2009 we established a new Circumpolar Active Layer Monitoring (CALM) site in the Limnopolar Lake basin on Byers Peninsula, Livingston Island. We monitored air, surface and ground (two boreholes of 135 and 80 cm deep) temperatures and Active Layer Thickness (ALT) was measured by mechanical probing in early February 2009, 2010 and 2011. The mean ALT was 44 cm with a range of about 92 cm, but where permafrost existed it was deeper than 1.0 m, as could be inferred from the borehole temperatures. ALT at this site was very dependent on air temperature and snow cover thickness, the ALT spatial distribution presenting the same pattern as soil penetration resistance, and higher values ALT coinciding with sites where patterned ground, ponds, and a near surface ground water saturation were observed. Additionally, ground temperature data provided an excellent tool for understanding the relationship between the ALT measured during the thaw season and the thermal evolution of the ground throughout the year.

The elephant seal populations breeding on the Îles Crozet and Kerguelen were regularly surveyed over the last three decades. At Îles Kerguelen the number of breeding females decreased at an annual rate of 3.6% between 1970 and 1987, then increased at an annual rate of 1.1% to 1997. At Îles Crozet, the population was reported to decrease at a rate of 5.35% between 1970 and 1990 but no change in numbers was found between 1990 and 1997. These results indicate that the rapid decline observed both at Îles Crozet and Îles Kerguelen has ended, and these populations are now either stable or slightly increasing. We suggest that broad scale change in environmental factors affecting the food availability for elephant seals may be responsible for the change in numbers of these marine predators. The higher rate of decrease, the longer period of decline, and the absence of any significant change between 1990 and 1997 observed on the Îles Crozet may be explained by additional factors such as killer whale predation.

We examine some aspects of the performance of the United Kingdom Meteorological Office's new climate model over Antarctica. Pressure and temperature fields are presented as a basic check on the model climate. The gradient of pressure between mid-latitudes and high southern latitudes is too great, resulting in an Antarctic trough that is too deep by 4–6 hPa. Temperature is well modelled though the interior is slightly too cold in winter. Precipitation is interesting because of its relevance to mass balance and therefore changes in sea level. The simulation of the pattern of accumulation is good despite somewhat high values at places in the coastal areas, with an areally-averaged value of 182 mm y−1. We also look at the phenomena of the coreless winter and the katabatic winds which are a consequence of the intense radiative cooling. These two effects may provide a useful diagnostic of the model performance.

The Ross Sea is an area of dense water formation within the Southern Ocean, hence it potentially plays an important role for anthropogenic CO2 sequestration. In order to estimate the penetration of anthropogenic carbon in the Ross Sea from total inorganic carbon (TCO2) measurements carried out in 2002–03 Antarctic Italian Expedition, we applied two independent models. Anthropogenic carbon was present throughout the water column. The highest concentrations were associated with the recently ventilated shelf waters, namely High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), due to their recent contact with the atmosphere. The lowest concentrations were observed for Circumpolar Deep Water (CDW), due to its relatively older ventilation age. This water mass intrudes onto the shelf in some parts of the Ross Sea and hence is observed in the sampled section, where it is recognizable for its low O2 and high TCO2 concentrations. The overflow of the dense High Salinity Shelf Water out of the continental slope was observed in the area off Cape Adare. Since this recently formed shelf water contributes to the formation of the Antarctic Bottom Water (AABW), this process represents a pathway for anthropogenic carbon export down to the deep ocean.

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.

Concentrations of dissolved monocarbohydrates (MCHO) and polycarbohydrates (PCHO) were analysed in a variety of ice habitats from summer Weddell Sea sea ice (surface ponds, ice cores, gap layers and platelet ice). The dissolved organic carbon (DOC) pool in these habitats was also measured and the contribution of carbohydrate to this pool was assessed. The DOC concentrations within all sea ice habitats were high compared to surface seawater concentrations with values up to 958μMC being measured. Total carbohydrates (TCHO) were highest in the ice cores and platelet ice samples, up to 31% of the DOC pool, a reflection of the high algal biomass in these two habitat classes. TCHO in the other habitats ranged between 10% and 29% of DOC. The ratios of MCHO to PCHO varied considerably between the ice habitats: in surface ponds and ice cores MCHO was 70% of the TCHO pool, whereas in gap layers and platelet ice there were lower PCHO concentrations resulting in MCHO being 88% of TCHO.

The myctophid, Electrona antarctica, was collected by trawl from the Elephant Island region of the Antarctic Peninsula, and from East Antarctica near 61°S and 93°W. Total lipid was higher in Elephant Island E. antarctica (whole fish, 466–585 mg g−1 dry weight) than those from Eastern Antarctica (394–459 mg g−1). Wax esters comprised 86.2–90.5% of total lipid in E. antarctica flesh. There were no significant differences between Eastern Antarctica and Elephant Island in total wax ester levels, or in levels of wax esters between different tissues analysed. Oily bones (up to 326 mg g−1 in the neurocranium) characterized E. antarctica from both locations, with wax esters as the major skeletal lipid class (67.0–87.9%, percent of lipid). The wax esters may have a buoyancy role in E. antarctica. The only substantial amount of triacylglycerols (29.4%) were found in the viscera of Elephant Island fish. The principal fatty acids of all fish analysed included the monounsaturated fatty acids 18:1(n-9) and 16:1(n-7), with lower levels of 16:0 and 14:0 saturated acids. Fatty alcohols were dominated by the saturated 16:0 and 14:0 (37.8–47.8%) and the monounsaturated 18:1(n-9) and 18:1(n-7) (38.3–59.2%). The low ratio of 22:1/20:1 alcohols observed for E. antarctica is consistent with a diet of amphipods, copepods and other items low in 22:1 alcohols.

Seventy-three sponge species were caught at 23 stations on the continental shelf of the Lazarev and Weddell Sea (Atlantic sector of the Southern Ocean). Tedania tantula was the most often found species amongst the 63 demosponge species caught and among the five hexactinellid species Rossella racovitzae was most common. The stations were classified according to their species inventory, and so the individual stations of the resulting four groups were rather uniformly dispersed over the entire investigation area. The species composition of adjacent stations varied considerably. There was no discernible relationship between the biological set of data and any combination of the available environmental characteristics of the stations. The sponge fauna of the, so far very poorly investigated, Lazarev Sea did not differ considerably from that of the adjacent Weddell Sea. The only species to be recorded for the first time on the Antarctic continental shelf were Homaxinella flagelliformis and Hyrtios arenosa. Small scale environmental events such as iceberg scouring, or biological characteristics such as extremely slow growth and budding reproduction are thought to generate the patchy distribution pattern.

The internal structure of ice cores from western Ross Sea pack ice floes showed considerable diversity. Snow-ice formation made a small, but significant contribution to ice growth. Frazil ice was common and its growth clearly occurred during both the pancake cycle and deformation events. Congelation ice was also common, in both its crystallographically aligned and non-aligned varieties. Platelet ice was found in only one core next to the Drygalski Ice Tongue, an observation adding to the increasing evidence that this unusual ice type occurs primarily in coastal pack ice near ice tongues and ice shelves. The diverse internal structure of the floes indicates that sea ice development in the Ross Sea is as complex as that in the Weddell Sea and more complex than in the Arctic. The mean ice thickness at the ice core sites varied between 0.71 m and 1.52 m. The thinnest ice generally occurred in the outer pack ice zone. Regardless of latitude, the ice thickness data are further evidence that Antarctic sea ice is thinner than Arctic sea ice.

Fast ice plays important physical and ecological roles: as a barrier to wind, waves and radiation, as both barrier and safe resting place for air-breathing animals, and as substrate for microbial communities. While sea ice has been monitored for decades using satellite imagery, high-resolution imagery sufficient to distinguish fast ice from mobile pack ice extends only back to c. 2000. Fast ice trends may differ from previously identified changes in regional sea ice distributions. To investigate effects of climate and human activities on fast ice dynamics in McMurdo Sound, Ross Sea, the sea and fast ice seasonal events (1978–2015), ice thicknesses and temperatures (1986–2014), wind velocities (1973–2015) and dates that an icebreaker annually opens a channel to McMurdo Station (1956–2015) are reported. A significant relationship exists between sea ice concentration and fast ice extent in the Sound. While fast/sea ice retreat dates have not changed, fast/sea ice reaches a minimum later and begins to advance earlier, in partial agreement with changes in Ross Sea regional pack ice dynamics. Fast ice minimum extent within McMurdo Sound is significantly correlated with icebreaker arrival date as well as wind velocity. The potential impacts of changes in fast ice climatology on the local marine ecosystem are discussed.

Small Unmanned Meteorological Observer (SUMO) unmanned aerial vehicles (UAVs) were used to observe atmospheric boundary layer temperature profiles in the vicinity of McMurdo Station, Antarctica during January and September 2012. The observations from four flight days are shown and exhibit a variety of boundary layer temperature profiles ranging from deep, well-mixed conditions to strong, shallow inversions. Repeat UAV profiles over short periods of time (tens of minutes to several hours) revealed rapid changes in boundary layer structure. The success of the SUMO flights described here demonstrates the potential for using small UAVs for Antarctic research.

Swimming activity of the Antarctic scallop at a temperature of c. −1.4°C was analysed using in situ video recordings obtained from a remotely operated vehicle (ROV) in Terra Nova Bay, Ross Sea. Data are presented on swimming trajectories, distance travelled and velocity during a swimming bout, adduction frequency, shell gape angle, and the angular opening and closing velocities of shell. This scallop is an effective swimmer although swimming bouts in response to the ROV were generally short, consisting of 2–5 adduction cycles in the take-off phase followed by 1–4 (exceptionally 14) adductions during level swimming. The maximum velocity during each adduction cycle ranged from 19.4–43.1 cm s−1 and the mean velocity during a swimming bout from 12.0–23.5 cm s−1. Each adduction cycle consists of opening, closing and glide phases of approximately equal duration. Adduction frequency during swimming averaged 1.5 adductions s−1.

The continental margin of Gondwana preserves a record of long-lived magmatism from the Andean Cordillera to Australia. The crustal blocks of West Antarctica form part of this margin, with Palaeozoic–Mesozoic magmatism particularly well preserved in the Antarctic Peninsula and Marie Byrd Land. Magmatic events on the intervening Thurston Island crustal block are poorly defined, which has hindered accurate correlations along the margin. Six samples are dated here using U-Pb geochronology and cover the geological history on Thurston Island. The basement gneisses from Morgan Inlet have a protolith age of 349±2 Ma and correlate closely with the Devonian–Carboniferous magmatism of Marie Byrd Land and New Zealand. Triassic (240–220 Ma) magmatism is identified at two sites on Thurston Island, with Hf isotopes indicating magma extraction from Mesoproterozoic-age lower crust. Several sites on Thurston Island preserve rhyolitic tuffs that have been dated at 182 Ma and are likely to correlate with the successions in the Antarctic Peninsula, particularly given the pre-break-up position of the Thurston Island crustal block. Silicic volcanism was widespread in Patagonia and the Antarctic Peninsula at ~ 183 Ma forming the extensive Chon Aike Province. The most extensive episode of magmatism along the active margin took place during the mid-Cretaceous. This Cordillera ‘flare-up’ event of the Gondwana margin is also developed on Thurston Island with granitoid magmatism dated in the interval 110–100 Ma.