We describe a new chimaeriform fish, Callorhinchus torresi sp. nov., from the uppermost Cretaceous (late Maastrichtian) of the López de Bertodano Formation, Isla Marambio (Seymour Island), Antarctica. The material shows it is distinct from currently known fossil and extant species of the genus, whereas the outline of the tritors (abrasive surfaces of each dental plate) shows an intermediate morphology between earlier records from the Cenomanian of New Zealand and those from the Eocene of Isla Marambio. This suggests an evolutionary trend in tritor morphology in the lineage leading to modern callorhynchids, during the Late Cretaceous-Palaeogene interval.

Data on the distribution, abundance and population structure of krill in the Prydz Bay area during January–February 1985 are considered in relation to hydrography and phytoplankton standing stocks. Stratified mean density and biomass estimated for the whole surveyed area from RMT-8 hauls were among the lowest recorded (3.3 individuals 1000 m−3 and 3.1 g 1000 m−3) confirming Prydz Bay as a low krill abundance area in the Southern Ocean. Age cohorts 1+ to 4+ were present, the size of the animals increased from south to north and juveniles were mostly found in surface waters near the pack-ice. Adults were in an active reproductive phase: 98% of the females were mated and 35% were ready to spawn whereas 86% of the males carried spermatophores. Breeding was taking place in oceanic waters over deep zones with the spawning season limited to January-April. Phytoplankton biomass was also very low in the area (mean of 29 mg Chl a m−2 in the upper 200 m) and currents speed low, never reaching 10 cm s−1. Krill distribution was strongly related to water circulation pattern but not related to phytoplankton distribution.

During a cruise to the Ross Ice Shelf we counted all penguins and marine mammals seen whilst underway. Our objective was to determine the abundance and distribution of these animals along our cruise line. From 14 May until 11 June the sun was below the horizon. Our observations were from the 18 m high bridge. Most watches were in the dark, aided by the bridge spotlights. A total of 79 emperor penguins, 920 Adélie penguins, and 27 marine mammals were counted. We conclude that the Ross Sea, in which wildlife flourishes during the summer, is depauperate in winter. The low numbers of marine mammals may be due partially to their tendency to remain below the surface most of the time. However, Adélie penguins, a visual hunter which rests on sea ice at night, appear to prefer pack ice edges where there is a few hours of daylight and civil twilight for pursuit of prey. Non-breeding emperor penguins also rest on sea ice at night. All but four were observed north of the Ross Sea. Unlike more northerly colonies where females lay their egg and disperse in May female departure in the Ross Sea appears to be later and, we were unable to determine their winter foraging area.

The statolith microstructure was studied in 142 females (mantle length, ML, ranging from 77–402 mm) and 119 males (72–328 mm ML) of Martialia hyadesi caught on the Patagonian and Falkland shelves and at the Antarctic Polar Frontal Zone between 1989–94. The statolith microstructure dark zone in this species, contains narrower and more numerous growth increments than the dark zones of other ommastrephid squids. Assuming daily production of putative growth increments within statoliths males live up to 12 months, and females live up to 13 months. It is likely that the life cycle lasts c. 1 yr, but immature squids with ages >330–340 d suggest that a part of M. hyadesi populations could have life span >1 yr. Growth in length was best described by the Gompertz function, whereas growth in weight was best described by the logistic function. M. hyadesi is characterized by slow juvenile growth (<100 mm ML), fast growth of immature squids and a sharp decrease in growth rates during maturation. M. hyadesi mature later (at ages >270 d) than other temperate ommastrephids, but maturation is rather rapid (2–3 months). In the south-west Atlantic, M. hyadesi hatch throughout the year.

Macaroni penguins (Eudyptes chrysolophus) and rockhopper penguins (E. chrysocome) account for a substantial proportion of the avian biomass at the subantarctic Prince Edward Islands (47°S, 38°E) in summer, when both species are breeding at the islands. Information on breeding population sizes, breeding and moulting activities, and diets were combined with measurements of the penguins' energy expenditures to construct a bioenergetic model of their energy requirements and food consumption at the islands. Total energy requirements of adults and chicks amounted to 460 × 109 kJ and 162 × 109 kJ for macaroni and rockhopper penguins, respectively. Food consumption was estimated to amount to a total of 166 000 tonnes during the seven-month breeding and moulting cycle, of which macaroni penguins consumed 75%. Most, if not all, of this food is taken within a 200-km radius of the islands. Available information suggests that potential primary production in the immediate vicinity of the islands is sufficient to support the macaroni and rockhopper penguin populations. However, the importance in the diets of the penguins of several prey species more typical of Antarctic and subtropical regions suggests that the penguins rely to a large extent on the importation of prey populations from other areas.

Sea ice provides a habitat for a conspicuous and productive assemblage of autotrophic microalgae and for heterotrophs ranging from bacteria to vertebrates (Horner 1990, Garrison 1991). With the exception of a reference to chytridiaceous fungi that were found infecting Arctic ice diatoms (Horner 1977) and a note in a cruise report (Schnack-Schiel 1987, p. 153), it appears that fungi and similar organisms have until now not been mentioned as members of the heterotrophic sea ice community. In the present short note we report on the abundant occurrence of apparently thraustochytrid fungus-like protists associated with mucilage tubes of pennate diatoms, encountered in the lower section of a fast ice core drilled close to the southern shelf ice margin of the Weddell Sea.

Shell bed levels in the Low Head Member of the early Oligocene Polonez Cove Formation at King George Island, West Antarctica, are re-interpreted based on sedimentological and taphonomic data. The highly fossiliferous Polonez Cove Formation is characterized by basal coastal marine sandstones, overlain by conglomerates and breccias deposited in fan-delta systems. The shell beds are mainly composed of pectinid bivalve shells of Leoclunipecten gazdzickii and occur in the basal portion of the Low Head Member. Three main episodes of bioclastic deposition are recorded. Although these shell beds were previously interpreted as shelly tempestites, we present an alternative explanation: the low fragmentation rates and low size sorting of the bioclasts resulted from winnowing due to tidal currents (background or diurnal condition) in the original bivalve habitat. The final deposition (episodic condition) was associated with subaqueous gravity driven flows. This new interpretation fits with the scenario of a prograding fan-delta front, which transported shell accumulations for short distances near the depositional site, possibly between fair-weather and storm wave bases. This work raises the notion that not every shell bed with similar sedimentological and taphonomic features (such as geometry, basal contact, degree of packing and shell orientation in the matrix) is made in the same way.

A hawaiite dyke dated at 3.88 ± 0.05 Ma from the Mount Morning eruptive centre intrudes a diamictite deposit at Gandalf Ridge in the southern Ross Sea. The dyke has been dextrally offset up to 6 m horizontally by faults interpreted as the onshore continuation of the West Antarctic rift system (WARS) fault array. Felsic dykes emplaced during the Miocene are also present at Gandalf Ridge. The offset of the Miocene dykes is equivalent to the offset on the hawaiite dyke, suggesting that at this locality movement on faults within WARS has been restricted to a period more recent than c. 3.88 Ma. Over this period the minimum average rate of movement on these faults within WARS is 0.0015 mm yr-1.

The endemic Antarctic scallop Adamussium colbecki (Mollusca: Bivalvia) represents a key species in the Ross Sea littoral benthic ecosystem, locally reaching very high densities. This species has an annual gametogenic cycle, with a summer spawning event, and a pelagic larval behaviour. This paper aims at describing population structure and genetic polymorphism (using AFLP) of the large populations inhabiting the Ross Sea (Terra Nova Bay and McMurdo Sound) in order to investigate possible genetic exchange between A. colbecki in these areas. In Terra Nova Bay, size-frequency distributions show, generally, the dominance of large individuals, although site related differences are found in the abundance of smaller size classes (less than 40 mm), suggesting that recruitment is not a regular event. All McMurdo sites are characterized by large individuals and, at least during this sampling period, recruitment is completely absent. Nuclear DNA analyses show that the largest differences are found at the largest scale (between McMurdo Sound and Terra Nova Bay), but all populations sampled, even at a smaller spatial scale, have a well-settled genetic structure, notwithstanding the pelagic larval strategy. The panmixia hypothesis has therefore to be rejected for this species.

High-resolution trends of nutrients and DOM are analysed, with respect to nitrate and ammonium uptakes, in two coastal stations placed on the annual land-fast ice at Terra Nova Bay. The highest accumulations of dissolved inorganic nitrogen (87.2 µmol N dm-3), reactive phosphorus (14.1 µmol P dm-3) and reactive silicon (22.9 µmol Si dm-3) were observed in the bottom ice, although this process was preceded by a nutrient decrease in an interior sea ice layer. In the upper layer of sea ice, DOM was rather constant in concentration and P-deficient (C:N:P = 377:34:1–579:53:1). In the bottom and platelet ice, the accumulation of DOM (1277 µmol C dm-3; 108.2 µmol N dm-3; 7.67 µmol P dm-3) occurred with lower C:N:P ratios (123:14:1–59:7:1), because of a major contribution of fresher organic matter. Nitrate (< 7.33 µmol N dm-3 d-1) and ammonium (< 2.85 µmol N dm-3 d-1) uptakes in the bottom ice were higher than in the platelet ice. The comparison between the data of N-uptake and the concomitant release of total dissolved nitrogen in the bottom ice indicated that the microbial community may be subjected to low growths in situ and high releases of dissolved nitrogen, when it accumulates in this sea ice habitat.

Precambrian continental extension is described in detail for the first time in the Victoria Land segment of the Transantarctic Mountains and is comparable with plume related intercontinental rifting of the Afar area, Africa. The Baronick Formation comprises igneous-derived conglomerate, marble and volcanic to sub-volcanic igneous layers. Volcanic and carbonate horizons were eroded in a fluvial or marine environment and provided debris for mass flow and slump deposits which formed in a marginal marine basin in the Precambrian. Clasts in these deposits include basalt, trachyte and comendite, and along with the interbedded volcanic layers of basalt, trachyte and quartz syenite, indicate proximity and contemporaneity of volcanic activity. Igneous layers and source rocks for clasts of the Baronick Formation have an enriched MORB chemistry and underwent albitization of calcic feldspar before erosion and conglomerate deposition. The Highway Suite forms a kilometre-scale body of gabbro and dolerite plugs and is interpreted as a slice of transitional continental oceanic crust. The chemistry of all igneous rocks suggests a continental rift environment and the associated sediments are consistent with such a setting. The Baronick Formation was locally intruded by sills of the Highway Suite; however, the main body of the Highway Suite was juxtaposed against the Baronick Formation during greenschist facies shearing before c. 551 Ma.

A survey of nearshore areas in the Vestfold Hills, Antarctica, using high-resolution multibeam swath bathymetry provided both a detailed digital bathymetric model and information on sediment acoustic backscatter. Combined with underwater video transects and sediment sampling, these data were used to identify and map geomorphic units. Six geomorphic units identified in the survey region include: rocky outcrops, basins, pediments, valleys, scarps and embayments. In addition to geomorphic units, the data revealed sedimentary features that provide insights into post-glacial sediment transport and erosion in the area. Ice keel pits and scours are common, and sea floor channels, scour depressions and sand ribbons indicate transport and deposition by wind-driven currents and oceanographic circulation. Gullies and sediment lobes observed on steep slopes indicate mass movement of sediment. Some of these processes have not been directly observed to date, but their effectiveness in shaping the modern sea floor is clearly indicated by the sea floor mapping data. The embayments preserve a mantle of boulder sand probably deposited by cold-based glaciers which were flanked by faster-flowing ice in adjoining regions.

Ground ice is one of the most important and dynamic geologic components of permafrost; however, few studies have investigated the distribution and origin of ground ice in the McMurdo Dry Valleys of Antarctica. In this study, ice-bearing permafrost cores were collected from 18 sites in University Valley, a small hanging glacial valley in the Quartermain Mountains. Ground ice was found to be ubiquitous in the upper 2 m of permafrost soils, with excess ice contents reaching 93%, but ground ice conditions were not homogeneous. Ground ice content was variable within polygons and along the valley floor, decreasing in the centres of polygons and increasing in the shoulders of polygons towards the mouth of the valley. Ground ice also had different origins: vapour deposition, freezing of partially evaporated snow meltwater and buried glacier ice. The variability in the distribution and origin of ground ice can be attributed to ground surface temperature and moisture conditions, which separate the valley into distinct zones. Ground ice of vapour-deposition origin was predominantly situated in perennially cryotic zones, whereas ground ice formed by the freezing of evaporated snow meltwater was predominantly found in seasonally non-cryotic zones.

Antarctic marine invertebrates from the Western Antarctic Peninsula (WAP) are generally stenothermal, with three-month survival and activity limits above the average maximum summer seawater temperature (1.0°C) of 1–6°C and 1–3°C respectively. For many of these species to survive the warmer maximum temperature at the sub-Antarctic island of South Georgia (5°C), they require either greater thermal flexibility, or must avoid the warmest water-masses. The mean depths and depth range of WAP gastropod and bivalve molluscs were compared with the mean depths of these same species at South Georgia; separated into water masses delimited by the 1°C isotherm at South Georgia, surface Antarctic water (SAW < 90 m), winter water (WW 90–150 m) and circumpolar deep water (CDW > 150 m). Bivalves in the SAW and CDW categories at the WAP were centred around the cooler WW (< 1.2°C) at South Georgia, with a narrower mean depth range for CDW bivalves. There was no difference in the average depth of gastropods, but a reduced depth range in the CDW. The apparent temperature limit to bivalve mean depths and not gastropods at South Georgia, suggests that further latitudinal comparisons could yield information on the underlying physiological mechanisms determining the range limits of Southern Ocean fauna.

Ice-free regions of Antarctica are concentrated along the coastal margins but are scarce throughout the continental interior. Environmental changes, including the introduction of non-indigenous species, increasingly threaten these unique habitats. At the same time, the unique biotic communities subsisting in isolation across the continent are difficult to survey due to logistical constraints, sampling challenges and problems related to the identification of small and cryptic taxa. Baseline biodiversity data from remote Antarctic habitats are still missing for many parts of the continent but are critical to the detection of community changes over time, including newly introduced species. Here we review the potential of standardized (non-specialist) sampling in the field (e.g. from soil, vegetation or water) combined with high-throughput sequencing (HTS) of bulk DNA as a possible solution to overcome some of these problems. In particular, HTS metabarcoding approaches benefit from being able to process many samples in parallel, while workflow and data structure can stay highly uniform. Such approaches have quickly gained recognition and we show that HTS metabarcoding surveys are likely to play an important role in continent-wide biomonitoring of all Antarctic terrestrial habitats.

The Southern Ocean plays an important role in the global carbon cycle and, as a consequence, in the planetary climate equilibrium. The Ross Sea is one of the more productive regions in the Southern Ocean, due to strong phytoplankton blooms occurring during summer. Satellite remote sensing is a powerful tool for investigating such phenomena, especially if the bio-optical algorithms are tuned with in situ data. In this paper, after having compared the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the ENEA Lidar Fluorosensor (ELF), the SeaWiFS chlorophyll a (Chl a) algorithm is tuned in the Ross Sea by means of the ELF measurements. The Chl a concentrations obtained in this way have been the basis for estimating productivity values and their evolution during summer 1997–98. Three primary production models have been used, providing information on their accuracy and performance in the Antarctic environment. Our investigations suggest that the primary production was lower than usual during the period 3 December 1997–16 January 1998.

A compositionally varied swarm of mafic dykes in the Jetty Peninsula area was emplaced about 320 Ma ago (K-Ar age). There are three major groups: Group 1 dykes range from transitional-alkaline dolerites to camptonites, Group 2 are trachydolerites, and Group 3 are diorite to quartz diorite porphyries. Group 1 dykes have very similar ratios of most incompatible elements and were derived from the same (or a very similar) enriched lithospheric mantle source region (∈Nd −0.18 to −3.05) with high Nb and Ta (i.e., OIB, ocean island basalt, characteristics). However, the presence of several distinct subgroups with different incompatible element abundances implies significantly different degrees of melting. Group 2 trachy dolerites are much more fractionated (mg 22–36), but were apparently derived from a similar, although somewhat more enriched (∈Nd −2.26 to −4.63) source. Group 3 diorites are compositionally quite distinct and may have been derived by intracrustal melting. Enrichment of the mantle source(s) of Groups 1 and 2 dykes apparently occurred about the same time as high-grade metamorphism in the area, and may have been coeval with crust formation in nearby parts of Gondwana.

The biogeochemical cycle of lead in the marine coastal environment of Terra Nova Bay has been investigated by determining the lead concentration in a large number of matrices: marine sediments, pack ice, snow, seawater, marine microlayer, aerosol and eight species of marine organisms (the bivalve molluscs Adamussium colbecki and Laternula elliptica, the seastar Odontaster validus, the sea urchin Sterechinus neumayeri, the fish Trematomus bernacchii, the seaweeds Iridaea cordata and Phyllophora antarctica, and the nemertine worm Parborlasia corrugatus). The study of solid speciation of sediment showed that the site is not influenced by human activity and is hence suitable to examine natural processes. The concentration values found in the suspended paniculate matter (SPM) of pack ice core, aerosol, marine microlayer and seawater as well as the particulate morphology, investigated by SEM, seem to support the hypothesis that particulate lead is transferred from the atmosphere to the water column through three different mechanisms: (i) release of SPM from the pack ice during its melting, (ii) input from the continental land through wet deposition, (iii) transport by aerosol and marine microlayer. Concentration data both in the whole organism and in some target organs indicated two suitable biomonitor organisms: the bivalva Laternula elliptica (particularly its digestive gland) and the fish Trematomus bernacchii (particularly its bones).

Within Antarctica there are large gradients both in climate and in vegetation which offer opportunities to investigate links between the two. The activity (% total time active) of lichens and bryophytes in hydric and xeric environments was monitored at Livingston Island (62°39'S). This adds a northern site with a maritime, cloudy climate to previous studies in the southern Antarctic Peninsula and the Dry Valleys (78°S). Annual activity increases northwards from less than 1% to nearly 100%. There is a major and consistent difference between hydric sites which, with snow melt, can be 100% active in summer months even in the Dry Valleys, and xeric sites which, depending on precipitation, rarely exceed 80% activity even at Livingston Island. Mosses dominate hydric sites and lichens the xeric sites all along the gradient. Mean temperatures when active are 2–4°C at all sites, as liquid water is required. Light is a potential major stress reaching 880 µmol m-2 s-1 when active in continental sites. The lack of extremes in temperatures and light combined with high activity levels means that summer at Livingston Island is one of the better sites for lichen and bryophyte growth in the world.

The Adélie penguin (Pygoscelis adeliae) breeding population at Stranger Point, King George Island (25 de Mayo), increased in number from 1965/66 until 1980/81 after which it started to decrease almost continuously up to the present. A significant decrease in the number of breeding pairs and chicks crèched was observed between 1995/96 and 2013/14 (75% and 78%, respectively), although the rate of this decrease has slowed since 2006/07. Over the last seven years, larger interannual fluctuations were recorded in the number of breeding pairs and chicks in crèches, as well in the breeding success. The values for the index of breeding success during 2007/08, 2009/10 and 2012/13 were low and this parameter showed higher temporal fluctuation in the period 2007/08 to 2013/14. The reduction in breeding success and the number of chicks reared to crèche will unfavourably impact on future population size at Stranger Point through the reduction of new recruits. Although Adélie penguin population trends on the Antarctic Peninsula are linked to the marine environment variability (i.e. reduction in sea ice affecting the availability of prey), breeding success is also influenced by the amount of snow fall which has increased in recent years.