Horseshoe Valley (80°18′S, 81°22′W) is a 30 km wide glaciated valley at the south-eastern end of Ellsworth Mountains draining into the Hercules inlet, Ronne Ice Shelf. The ice at Horseshoe Valley has been considered stable; now we use Global Positioning System (GPS) measurements obtained between 1996 and 2006 to investigate ice elevation change and mass balance. Comparison of surface heights on a profile across Horseshoe Valley reveals a slight but significant elevation increase of 0.04 m a-1 ± 0.002 m a-1. The blue ice area of Patriot Hills (∼13 km2) at the mount of Horseshoe Valley shows large interannual variability in area, with a maximum extent in 1997, an exceptionally warm summer, but no clear multi-year trend, and an elevation increase of 0.05 m a-1 in eight years, which agrees with the result from Horseshoe Valley.

Emperor penguins require stable fast ice, sea ice anchored to land or ice shelves, on which to lay eggs and raise chicks. As the climate warms, changes in sea ice are expected to lead to substantial declines at many emperor penguin colonies. The most southerly colonies have been predicted to remain buffered from the direct impacts of warming for much longer. Here, we report on the unusually early breakup of fast ice at one of the two southernmost emperor penguin colonies, Cape Crozier (77.5°S), in 2018, an event that may have resulted in a substantial loss of chicks from the colony. Fast ice dynamics can be highly variable and dependent on local conditions, but earlier fast ice breakup, influenced by increasing wind speed, as well as higher surface air temperatures, is a likely outcome of climate change. What we observed at Cape Crozier in 2018 highlights the vulnerability of this species to untimely storm events and could be an early sign that even this high-latitude colony is not immune to the effects of warming. Long-term monitoring will be key to understanding this species' response to climate change and altered sea ice dynamics.

Marked spatial autocorrelation was encountered in an extensive data set on Antarctic seal densities as well as Antarctic pack ice characteristics. Whilst the methodology of measuring spatial autocorrelation is well developed, there is no established infrastructure for statistical inference in terms of correlation analysis or ANOVA. We survey the literature that deals with these problems, as well as some of the approaches that have been proposed for taking autocorrelation into account in inferential statistics. We apply these approaches to a data set comprising Antarctic pack ice seal counts as well as a few environmental measures. In contrast to the predictions from the existing literature, nonlinear estimation suggested that Pearson's r substantially overestimates the true correlation between seal densities and environmental variables. When compared to spatially adjusted analysis of variance, conventional ANOVA that compared seal densities or pack ice characteristics in different areas overestimated the degree of difference between these areas in proportion to the degree of spatial autocorrelation of the particular data set. In our case, the effects of spatial autocorrelation were not neutralised by treating entire transects as single points. These results emphasise the need for a methodology that takes spatial autocorrelation into account for interpreting the spatial data on Antarctic seals collected during the Antarctic pack ice seal (APIS) program. New software written for performing these analyses is available from the senior author.

Labidiaster annulatus, Sladen (1889) is a multi-rayed (9–50) voracious Antarctic sea star with numerous large, conspicuous crossed pedicellariae. An active and opportunistic predator, it commonly preys upon euphausiids, amphipods, and small fish in the water column (Dearborn et al. 1991). Labidiaster annulatus is distributed around the Antarctic, Kerguelen, South Orkney, South Sandwich Islands, South Georgia, and Shag Rocks, at recorded depths of 30–440 m (Fisher 1940, unpublished data).

High southern latitude island environments are unusual in having relatively low or, in some cases, no non-indigenous species (NIS). Here we describe the accidental transport and survivorship of moths (Lepidoptera, Noctuidae) on a research vessel travelling from southern South America (Montevideo, Uruguay) first to the cool temperate Falkland Islands and then onwards to Maritime Antarctic Signy Island (South Orkney Islands). On the vessel's arrival at Stanley, Falkland Islands, from Montevideo we found eight live (and 30 dead) individuals of two species of South American noctuid moth (Pseudaletia adultera Schaus and Peridroma saucia (Hübner)), presumed to have been attracted to the ship's lights while in port. Neither of these is indigenous to the Falkland Islands. Five of the eight living moths (all P. adultera) survived the four days the ship was moored in Stanley and one survived a further four day journey across the Polar Front to Signy Island. Southern oceanic islands are particularly vulnerable to invasion by NIS, with human (shipping) activities being the main route of arrival. With increasing shipping throughout this region some measures have been proposed or adopted to reduce the risk of NIS transfer.

The Antarctic bivalve Yoldia eightsi (Couthouy) has been assessed as a monitor species in the vicinity of a research station at Signy Island. For animals of comparable age n-alkane loading was highest at the site closest to the station. The character of the n-alkane pool of Yoldia varied with distance from the station and also differed from that of the sediment. The polycyclic aromatic hydrocarbon (PAH) loading was highest 250 m from the station. Loading of n-alkanes and PAH varied through the year; the lowest levels of n-alkanes were in October and the highest in April. The maximum for PAH was in October. Hydrocarbons increased with age for animals from five to 50 years old; 100–2000 ng animal−1 for n-alkanes and 1–21 ng animal−1 for PAH. Tissue concentrations decreased with age; 6000–500 μg kg1 for n-alkanes and 25–5 μg kg−1 for PAH. Several biogenic branched chain alkenes were also present; one C25.3 isomer was predominant at concentrations up to 290 μg kg−1 in mature animals (40% of the aliphatic fraction). Accumulation was not constant with age and concentrations reflected both anthropogenic and biogenic hydrocarbons in the marine environment. Seasonal variation in PAH load suggested the major proportion of accumulation over the year was only temporary. Yoldia eightsi were not suitable to monitor low level contamination such as that at Signy Island and past incidents were not resolved from the background input.

Magnetic, gravity and bathymetric data from Marguerite Bay are used to study the relationships between oceanic and continental tectonic evolution in the arc and fore-arc of the Antarctic Peninsula. The data are used to redefine the crustal structure of the Marguerite Bay area, providing evidence for a northward continuation of George VI Sound and the Alexander Island Mesozoic accretionary prism almost to the continental shelf edge. A two-stage model of extension, associated with changes in spreading rates and approaching ridge segments, is proposed to explain the crustal structure and Cenozoic tectonic evolution of the area. The model involves the opening of George VI trough by Tertiary dextral transtension, followed by oblique extension in an area bounded by the Tula and Adelaide fracture zones. This interpretation confirms previous work linking oceanic tectonic processes with continental arc and fore-arc structural development.

The Patuxent Range forms the most southerly third of the Pensacola Mountains, East Antarctica. Largely unstudied since the original geological survey work of the 1960s, the Patuxent Range was thought to expose metasediments deformed by a single Precambrian event. However, new structural data collected from two geographically separate areas in the central Patuxent Range reveal the presence of three distinct generations of structures. A synthesis of the regional geology together with new data suggests that the Patuxent Formation was mildly deformed during end Cambrian times as part of the late stage Ross Orogeny. However, the most intense deformation, although poorly constrained in age, probably occurred during the Permo-Triassic Gondwanian Orogeny. A third phase of deformation predates the intrusion of 183 Ma lamprophyre dykes and involved an inferred vertical axis rotation of the pre-existing D1 and D2 structures and the localized development of a spaced foliation and mesoscale folding. These D3 structures may be the first evidence of an Early Jurassic deformation event in the Transantarctic Mountains, which correlates with the Peninsula and Rangitata I orogenies of the Antarctic Peninsula and New Zealand, respectively.

The oldest record of the hexanchiform sharks from the Southern Hemisphere and the second chondrichthyan report known from Carboniferous to Early Cretaceous beds in Antarctica is given. The material was collected in late Aptian rocks of the Kotick Point Formation outcropping in the western part of James Ross Island, near Antarctic Peninsula. It consists of an isolated tooth assignable to a hexanchiform different from the other described genera. The tooth shows putative plesiomorphic cusp (few cusps, no serrations) and apomorphic root characters (relatively deep, quadrangular). It could be related to a species close to the origin of Hexanchus (unknown in beds older than Cenomanian).

Habitats under ice shelves are minimally explored, primarily because of technological limitations. These areas are separated from photosynthetic primary productivity by thick ice and distance to open water. Nevertheless, a diverse macrofaunal benthic community was discovered at 188 m depth, 80 km back from the edge of the McMurdo Ice Shelf. The general habitat was fine sediment with occasional dropstones, and dominant taxa were polychaetes and brittle stars, with alcyonacean soft corals and anemones on hard substrates. Gelatinous animals were abundant near the seafloor, and possibly part of a food web that supports the benthic community.

Antarctic snow samples collected from the Wilkins Runway, c. 50 km inland from the Windmill Islands, East Antarctica, contain aeolian-derived diatoms. The diatom assemblage preserved is exclusively of marine origin. As diatoms are excellent indicators of source conditions, we are able to confirm that an unusual weather event, with anomalous north-westerly winds blowing at around 10 m s-1, resulted in the deposition of coastal marine species at the Wilkins Runway. The composition of the floral assemblage collected indicate that the parent water mass was from a coastal marine region undergoing typical Antarctic summer conditions with periods of both consolidated sea ice and open water. On inspection of available satellite imagery, these conditions were found upwind of the deposition site. This study provides a methodology for diatoms found within ice cores to be identified and the source region to be determined. It also provides evidence for a large-scale aeolian deposition of marine diatoms to an ice sheet, which may have implications for the interpretation of controversial marine diatoms found in sediments that have been used as evidence for the retreat of the East Antarctic Ice Sheet.

Ecosystem engineers such as the Antarctic scallop (Adamussium colbecki) shape marine communities. Thus, changes to their lifespan and growth could have far-reaching effects on other organisms. Sea ice is critical to polar marine ecosystem function, attenuating light and thereby affecting nutrient availability. Sea ice could therefore impact longevity and growth in polar bivalves unless temperature is the overriding factor. Here, we compare the longevity and growth of A. colbecki from two Antarctic sites: Explorers Cove and Bay of Sails, which differ by sea-ice cover, but share similar seawater temperatures, the coldest on Earth (-1.97°C). We hypothesize that scallops from the multiannual sea-ice site will have slower growth and greater longevity. We found maximum ages to be similar at both sites (18–19 years). Growth was slower, with higher inter-individual variability, under multiannual sea ice than under annual sea ice, which we attribute to patchier nutrient availability under multiannual sea ice. Contrary to expectations, A. colbecki growth, but not longevity, is affected by sea-ice duration when temperatures are comparable. Recent dramatic reductions in Antarctic sea ice and predicted temperature increases may irrevocably alter the life histories of this ecosystem engineer and other polar organisms.

The Horlick Formation is a fossiliferous, predominantly marine succession of interbedded sandstone and mudstone that crops out along a prominent escarpment in the Ohio Range. The formation buries a relatively level wave-cut platform eroded across a basement granitoid, and is nowhere more than 56 m thick due to subsequent Permo–Carboniferous glacial erosion.

The sediments have been described in terms of nine lithofacies (Bradshaw & McCartan 1983, McCartan & Bradshaw 1987), that were renamed in conjunction with the establishment of six ichnocoenoses (Bradshaw et al. 2002). An abundant but relatively limited shelly fauna was described by Doumani et al. 1965 and Bradshaw & McCartan 1991.

The six ichnocoenoses within the Horlick Formation have been used in palaeoenvironmental interpretations (Bradshaw et al. 2002). Catenarichnus is an important element and name bearer for one of these ichnocoenoses. Detailed descriptions of the remaining ichnofauna will be described in a separate paper.

An individual-based model is presented which describes the spatial and temporal evolution of phytoplankton growth in terms of a Lagrangian ensemble of cells affected by various physical and biological forcing factors. The motion of cells develops according to a turbulent velocity field which simulates the Antarctic mixed layer during the summer. The cell growth is a function of the irradiance regime, nutrient availability and the vertical position of the individual with respect to the other cells (in order to evaluate the self-shading effect). The values of photosynthetic parameters used to simulate the photophysiological response of the organisms are derived from measurements collected in the Ross Sea. In contrast to previous individual-based descriptions, all the physical and biological processes involved are explicitly reproduced in their dynamical features. Coupling different mixing levels with photoacclimation strategies leads to a wide range of photophysiological responses which underline the role of individual physiological histories in determining the growth of the population as a whole. Simulated photosynthetic parameters, chlorophyll a concentrations and integrated primary production correspond closely to in situ data and confirm that photoacclimation to low irradiance and strong mixing regimes may be considered as crucial factors in the photosynthetic performance of Antarctic phytoplankton.

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.

Sedimentary sequences spanning early Oligocene and Neogene time intervals were recovered with piston and gravity cores along erosional structures at northern Gunnerus Ridge and Kainan Maru Seamount in the southernmost Indian Ocean. Results of sedimentological investigations help to reconstruct the Cenozoic palaeoenvironment. Main emphasis was placed on grain size and clay mineral data. The clay mineral assemblages are dominated by illite and smectite. Chlorite and kaolinite occur in trace amounts. Whereas illite has a distinct source on the East Antarctic craton, smectite is of somewhat speculative origin, but probably is derived from erosion of Cenozoic or older shelf sediments. The presence of terrigenous sand indicates that ice-rafting was active throughout the time represented by the investigated cores, although with varying intensity. During the early Oligocene interval (30.1–29.0 Ma), siliceous phytoplankton production dominated sedimentation. Environmental conditions were quite different from those on Maud Rise and Kerguelen Plateau. The middle Miocene sedimentary sequence (14.1–12.8 Ma) documents an intensification of East Antarctic glaciation. The sediments deposited during the late Miocene interval (8.7–6.5 Ma) and the Pliocene interval (5.1–2.7 Ma) indicate continued cooling of Antarctica, but a more dynamic Antarctic ice sheet resulting in episodic sedimentation patterns.

Field observations involving landform evaluation and the physical characterization of sediments, combined with a detailed analysis of the spatial distribution of bedrock and sediment geochemical patterns, suggests a limit to the glacial transport half-distance of c. 3 km in Vestfold Hills. Four morphologically distinct glacial deposits were sampled (small debris ridges, large debris ridges, debris drapes and valley fills) on the basis of field geometry. These landforms were subsequently distinguished by grain size, mineralogy and geochemistry. Since there are no nunataks south of Vestfold Hills, all debris is derived subglacially and sedimentological differences are attributed to the physical weathering of preglacial surfaces in Vestfold Hills and fluvial winnowing during deposition. Given that thrust geometries may occur in large debris ridges, glacial transport distances were short, and fluvial sorting of sediments was an important mechanism, reconstructions of glacial histories based on the stratigraphy of deposits in Vestfold Hills should be made with caution.

Ibises are a group of medium- to large-sized, mainly wading birds in the family Threskiornithidae (Aves: Ciconiiformes; see also discussion in Mayr 2002). They are known from all the continents except Antarctica, though one species breeds as far south as Tierra del Fuego (del Hoyo et al. 1992, p. 499). The oldest fossil bones (including skull elements) attributed to ibises are those of Rhynchaeites messelensis Wittich, 1898 from the Middle Eocene of Messel, Germany (Peters 1983, Mayr 2002). Another supposed member of this group is the Pondaung bird from the late Middle Eocene of Myanmar (formerly Burma) represented solely by an incomplete tibiotarsus (Stidham et al. 2005, fig. 2). The taxonomic position of Minggangia changgouensis Hou, 1982 from the Late Eocene of China (Hou 1982) was recently questioned by Stidham et al. (2005, p. 183). Here, we present a partial bill from the Eocene La Meseta Formation (Seymour Island, Antarctica) which most closely resembles that of ibises.

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.