A 9.24 m sediment core, GA-2, was collected on the coastal platform of Grande Valley, a relatively narrow and shallow fjord in Fildes Peninsula, King George Island, Antarctica. The sediment was formed between 6600 and 2000 cal. yr bp according to accelerator mass spectrometry (AMS) 14C dating of five bulk sediment samples. The comprehensive proxy indicators (grain size, loss on ignition at 550°C, magnetic susceptibility, elements) were analysed, and three separate depositional environments and an alternating climate change pattern were identified. Grande Valley experienced a warm marine environment between 6600 and 5800 cal. yr bp, a minor cooling between 5800 and 4800 cal. yr bp, the transition from cool to warm during 4800–4400 cal. yr bp, a mid-Holocene climatic optimum between 4400 and 2700 cal. yr bp, and the onset of the Neoglacial at 2700 cal. yr bp. This study reconstructed the environmental history of Grande Valley during the mid–late Holocene, provides the missing marine record of historical climate for the western coast of Fildes Peninsula and lays the foundation for further study of the climate and environment changes therein. Our finding that the sea level was c. 12 m a.m.s.l. at 2000 cal. yr bp allows for detailed reconstruction of Holocene sea level variations.

The flightless midge Eretmoptera murphyi is thought to be continuing its invasion of Signy Island via the treads of personnel boots. Current boot-wash biosecurity protocols in the Antarctic region rely on microbial biocides, primarily Virkon® S. As pesticides have limited approval for use in the Antarctic Treaty area, we investigated the efficacy of Virkon® S in controlling the spread of E. murphyi using boot-wash simulations and maximum threshold exposures. We found that E. murphyi tolerates over 8 h of submergence in 1% Virkon® S. Higher concentrations increased effectiveness, but larvae still exhibited > 50% survival after 5 h in 10% Virkon® S. Salt and hot water treatments (without Virkon® S) were explored as possible alternatives. Salt water proved ineffective, with mortality only in first-instar larvae across multi-day exposures. Larvae experienced 100% mortality when exposed for 10 s to 50°C water, but they showed complete survival at 45°C. Given that current boot-wash protocols alone are an ineffective control of this invasive insect, we advocate hot water (> 50°C) to remove soil, followed by Virkon® S as a microbial biocide on ‘clean’ boots. Implications for the spread of invasive invertebrates as a result of increased human activity in the Antarctic region are discussed.

While ocean current and winds certainly play a major role in guiding the trajectories of free-floating icebergs, the direct effect of atmospheric surface pressure gradients can also have an important influence on the trajectories of large icebergs whose horizontal dimensions are sufficiently great to span synoptic systems. This effect is examined as a way of understanding why icebergs B15A, B15J, B15K, and C16 became “trapped” in a limited region immediately north of Ross Island for a period of several years, without being grounded. This limited region is otherwise flushed annually by summer surface winds and currents; thus the delay of the northward drift of the large icebergs (particularly B15A and B15J) defied expectation. The best explanation for this unexpected iceberg behaviour is that the large volcanic massifs on Ross Island create a quasi-permanent surface pressure anomaly patterned as a dipole, with high pressure in the area upwind of the island (an area appropriately called Windless Bight), and low pressure in the downwind area of the iceberg parking lot. The surface pressure regime experienced by two icebergs B15A and B15K is estimated using Automatic Weather Station observations and Global Positioning System receivers deployed on their surfaces to explain why they remained trapped. Breakdown of the atmospheric pressure gradients allowed them to eventually escape from the region to the north-west.

The occurrence and nature of weathered clasts in the CIROS-1 drill core from McMurdo Sound was recorded. These data showed both associations of weathered material with particular lithofacies and that certain lithologies were preferentially weathered. XRD analysis of weathering rinds from two lithostratigraphic core units suggest that such weathering data can provide evidence of terrestrial palaeoenvironmental conditions that may be otherwise unobtainable.

Researchers have previously assumed that common diving petrels (Pelecanoides urinatrix) have a limited sense of smell since they have relatively small olfactory bulbs. A recent study, however, showed that adult diving petrels prefer the scent of their own burrow compared to burrows of other diving petrels, implying that personal scents contribute to the burrow's odour signature. Because diving petrels appear to be adapted to use olfaction in social contexts, they could be a useful model for investigating how chemically mediated social recognition develops in birds. A first step is to determine whether diving petrel chicks can detect familiar and unfamiliar odours. We compared behavioural responses of chicks to three natural stimuli in a wind tunnel: soil collected from their burrow or colony, and a blank control. During portions of the experiment, chicks turned the least and walked the shortest distances in response to odours from the nest, which is consistent with their sedentary behaviour within the burrow. By contrast, behaviours linked to olfactory search increased when chicks were exposed to blank controls. These results suggest that common diving petrel chicks can detect natural olfactory stimuli before fledging, and lay the foundation for future studies on the role of olfaction in social contexts for this species.

Remote sensing provides the means to study features and processes that are not easily accessible or amenable to direct observations. The polar regions, and Antarctica in particular, offer a variety of examples where the ability to observe from afar is necessary or highly desirable. In particular, studies of ice shelf processes, changes in the sea-ice cover, and ice-ocean-atmosphere investigations must rely in large part on measurements from aircraft and satellites. The polar regions present a unique set of problems that complicate applications and limit the usefulness of certain sensors; new instruments planned for launch in the 1990s will help resolve many of these difficulties. Examples of remote sensing applications for the study of the continent, drifting ice, ocean, and atmosphere demonstrate ways that existing data as well as new observations can be used to aid polar research.

An isolated partial right dentary (BAS D.515.2) collected by the British Antarctic Survey prompted a re-evaluation of gadiform remains from the La Meseta Formation (conventionally middle Eocene) of Isla Marambio (Seymour Island), Antarctic Peninsula. Modern gadiforms (hakes and cods) range from the Arctic to Antarctic, inhabiting deep sea benthic, shore, estuarine, and freshwater environments. Based on a fossil record primarily composed of otoliths, they are known to extend back to the Eocene and Oligocene. The new specimen was recovered from the fossil penguin locality D.515. It is characterized by a single row of sharp, ankylosed teeth set upon robust bony pedestals. The surface anterior to the mental foramen exhibits ascending and descending ridges with slightly rugose texture. The ascending ridge is fractured, but partially covers the lateral aspect of the tooth row. BAS D.515.2 is unlike the dentary of macrourid gadiforms, also recovered from the Eocene of Antarctica. BAS D.515.2 preserves several features similar to previously published accounts of the gadiform “†Mesetaichthys” from Isla Marambio. These specimens are probably the same taxon and their combined character suite indicates it is a member of Merluccidae. Thus, these are the only non-otolithic skeletal specimens of an Eocene hake known outside of the London Clay's †Rhinocephalus.

Understanding primary productivity is a core research area of the National Science Foundation's Long-Term Ecological Research Network. This study presents the development of the GIS-based Topographic Solar Photosynthetically Active Radiation (T-sPAR) toolbox for Taylor Valley. It maps surface photosynthetically active radiation using four meteorological stations with ~20 years of data. T-sPAR estimates were validated with ground-truth data collected at Taylor Valley's major lakes during the 2014–15 and 2015–16 field seasons. The average daily error ranges from 0.13 mol photons m-2 day-1 (0.6%) at Lake Fryxell to 3.8 mol photons m-2 day-1 (5.8%) at Lake Hoare. We attribute error to variability in terrain and sun position. Finally, a user interface was developed in order to estimate total daily surface photosynthetically active radiation for any location and date within the basin. T-sPAR improves upon existing toolboxes and models by allowing for the inclusion of a statistical treatment of light attenuation due to cloud cover. The T-sPAR toolbox could be used to inform biological sampling sites based on radiation distribution, which could collectively improve estimates of net primary productivity, in some cases by up to 25%.

The jaw musculature of notothenioid fishes is described and compared based on a total of 38 species referred to eight families of the suborder Notothenioidei. In the Notothenioidei, the adductor mandibulae, the largest and most conspicuous of the cranial muscles, is generally composed of sections A1, A2, A3 and Aw as in the generalized percoids. The morphology of the adductor mandibulae is similar in most notothenioid families except the Nototheniidae and Bathydraconidae. Notothenia, Paranotothenia and Dissostichus are clearly distinguished from the other nototheniid genera in having A3. Gymnodraco of the Bathydraconidae has a fused A1-A2 complex and the anterior element is segmented by a tendinous intersection from the A1-A2 complex. These features are unique to Gymnodraco and not seen in other bathydraconids. The Harpagiferidae and Artedidraconidae share the same apomorphy, the presence of A1β, with the Nototheniidae and have no synapomorphies with the Bathydraconidae and Channichthyidae. The character distribution, however, shows some inconsistencies with the previous classifications. Based on the limited evidence obtained in this study, the Notothenioidei can be divided into six groups and it seems reasonable to suggest a review of the current classification of the Nototheniidae.

Ozone concentration measurements were made during December from 2001–2005 to quantify the contributions of different processes to near-surface ozone concentrations (O3) in Terra Nova Bay, Antarctica. The average O3 concentration was 20.3 ppbv. On days characterized by high solar radiation fluxes (HSR), significantly higher concentrations of O3 (21.3 ppbv) were recorded compared to days with low solar radiation fluxes (LSR days, 16.8 ppbv). High O3 concentrations could be related to strong winds from SW–NW. Three-dimensional back-trajectories show that air from the interior of the continent could affect O3 at Terra Nova Bay. Moreover, during HSR days, high O3 concentrations were also recorded in connection with weak circulation, suggesting that emissions from the Italian base (located 2 km north) could also represent a significant source of O3. To clarify the role of local pollution in Terra Nova Bay, O3 values were also calculated using the photochemical steady state (PSS) approximation under clear sky and cloudy conditions.

The interannual variability of net community production (NCP) and air-sea CO2 flux in a naturally iron fertilized and productive area of the Southern Ocean (Kerguelen plateau) was investigated using a 1D biogeochemical model driven by satellite chlorophyll, sea surface temperature and wind speed data for the 1997–2007 period. The model simulates the low fCO2 and dissolved inorganic carbon (DIC) measured during summers 2004–05, 2005–06, 2006–07 and the high NCP derived from a seasonal carbon budget in the surface waters of these blooms. Although satellite data show high interannual variability in the dynamics and magnitude of the bloom during the 1997–2007 decade, the simulated interannual variability of the NCP was only ± 14%. This unexpected result could be due to the combined effect of both the duration and the start date of the bloom, the latter determining the depth of the mixed layer used to compute the NCP. In the productive area, the interannual variability of air-sea CO2 flux (± 13%) was not only driven by the biological effect but also by the solubility effect. Our results contrast with previous studies in the high nutrient, low chlorophyll regions of the Southern Ocean.

In Antarctica, crabeater seals tend to strand as immature animals with disorientation, due to their inexperience, given as the probable cause. In 2012 and 2013, we examined a group of 80 mummified crabeater seals on Seymour Island (Marambio). The age and gender of 28 seals was determined, and virology and stomach content analyses were performed in order to determine the cause of stranding. Around 82% of the seals examined were adults and 79% were females, some of which were pregnant. All of the seals sampled tested negative for Morbillivirus, suggesting that the stranding was not related to the mass mortality event reported in the 1950s in the region. Most seals had empty stomachs and thin blubber suggesting that they died from starvation. The state of the carcasses suggests multiple stranding events. Most of the seals were located along an ice-covered stream, suggesting that this may act as a ‘natural trap’, isolating the seals from the open ocean. This is exceptional as it is the first report of mostly adult female seals to strand in Antarctica and refutes the theory that only young animals are prone to stranding.

Fluxes of dissolved oxygen and nutrients and vertical fluxes of particulate organic elements were investigated in the subtidal benthic environment of Marian Cove, King George Island, Antarctica, using in situ benthic chambers and near-bottom sediment traps. Fluxes of dissolved oxygen, ammonium, phosphate, and silicate were comparable to those measured in temperate regions. Sediment oxygen consumption was a good indicator of organic respiration and elemental efflux at the benthic boundary layer of Marian Cove, with good positive correlations with ammonia (r2 = 0.67), phosphate (r2 = 0.57), and the C:N:P ratio (106:11.5:1.15) in the chamber water. A positive relationship (r2 = 0.58) between settling particulate organic carbon flux and chl a concentration suggests that water column biomass and production are direct sources of settling particles. According to element budgets in summer assessed using the fluxes, Jin and the sum of Jout and Jburial were 15.9 ± 8.1 and 22.6 ± 8.2 mmol m-2 d-1 for carbon, 2.02 ± 0.54 and 2.46 ± 0.82 mmol m-2 d-1 for nitrogen, 0.07 ± 0.03 and 0.23 ± 0.08 mmol m-2 d-1 for phosphorus, and 12.4 ± 2.7 and 13.5 ± 5.0 mmol m-2 d-1 for silicon, respectively. There was a broad balance between sediment organic input and remineralized output for carbon and nitrogen at the benthic boundary layer of Marian Cove.

A prominent volcaniclastic channel sandstone deposited by a landward-flowing sediment gravity flow is described from the Maastrichtian of Snow Hill Island in the northern Larsen Basin. The characteristics of this petrographically distinct event deposit appear to indicate a volcanic source to the east of Snow Hill Island, well away from the magmatic arc landmass which sourced the bulk of the Larsen Basin fill, suggesting minor off-axis intrabasinal volcanism in Maastrichtian to Paleogene times.

Biomass allocation and growth by the clonal plant Acaena magellanica were characterized for three populations grazed by introduced reindeer on the subantarctic island of South Georgia. Annual growth markers (internode lengths) were used to divide each rhizome into current year's shoots, one-year-old and two-year-old rhizome segments. Total dry weights were significantly smaller in grazed than in ungrazed populations. Leaf biomass of current year's shoots was very much lower in grazed shoots. Rhizome length and number of leaves were less affected than dry weight by grazing, and the reindeer grazing thus seems to mainly influence biomass accumulation rather than morphology in Acaena. Interactions with Festuca contracta in both grazed and ungrazed areas were also studied in a two-year competition experiment. No apparent release of soil resources (as measured by an increase in plant growth) was apparent in plots where Festuca was removed, but the current year's shoots of Acaena were smaller and more numerous in these plots than in controls, especially in the ungrazed area.

The momentum budget of the boundary layer flew near the Swedish research station Svea in the mountainous region of western Dronning Maud Land, Antarctica, is evaluated using detailed concurrent observations of surface meteorological variables, high-resolution boundary layer profiles and upper-air profiles taken during the summer of 1997–98. Despite the fact that the irregular topographical situation prohibits easy interpretation of the data, interesting features can still be identified. All terms in the momentum budget (katabatic forcing, synoptic pressure gradient, Coriolis force and friction) can be of the same order of magnitude, which indicates that the influence of each term depends largely on the prevailing conditions. More precisely, the relative importance of the various momentum terms varies strongly with altitude, location, time of day and prevailing synoptic conditions. For example, at the undisturbed snow slopes there is a very regular daily variation of katabatically forced flow during the night and a flow dominated by the synoptic pressure gradient during the day, causing a persistent diurnal cycle in surface wind direction. The interpretation of the flow characteristics in terms of the momentum budget agrees favourably with the conclusions drawn on the basis of a general description of the prevailing meteorological conditions, and can therefore be considered consistent.

This study provides new species records (NRs) of macroalgal assemblages present in rocky habitats from the South Shetland Islands (SSI) and north-eastern Antarctic Peninsula (EAP), Weddell Sea. Surveys were conducted during the summers of 2013/2014 to 2017/2018 at Elephant, Deception, Half Moon and Vega islands. Data from the present study and those available in the literature from the western Antarctic Peninsula (WAP) were combined to provide an updated checklist, giving insights into macroecology and potential changes in thermohaline circulation patterns. A total of 48 macroalgal taxa were identified from our sampling, with eight representing NRs to the EAP sector of the Weddell Sea and five representing NRs to the SSI. Statistical differences among the assemblages from the SSI, WAP and EAP were identified. NRs, including opportunistic species and new information about the biogeographical distributions of species reported here, give insights into ecoregional connectivity and environmental changes. This study updates macroalgal diversity records in regions that are currently experiencing the impacts of climate change. Future and ongoing monitoring for conservation purposes is required to detect non-native species, new dispersal pathways and patterns related to thermohaline anomalies in Antarctic waters.

New outcrops of Hope Bay Formation and Larsen Basin rocks have been exposed by recent ice-retreat on Tabarin Peninsula, northern Antarctic Peninsula. Quartzose, very low-grade metasedimentary rocks, cropping out at Balegno Nunatak (63°28′53″S, 57°00′31″W) are assigned to the Permian–Triassic Hope Bay Formation, and dioritic rocks are assigned to the Antarctic Peninsula batholith. Sedimentary rocks exposed at Rubulis Nunatak (63°30′52″S, 57°07′29′W) closely resemble Lower Cretaceous sedimentary rocks cropping out at nearby Troilo Nunatak, western Tabarin Peninsula. These rocks are correlated with the lower Gustav Group (?Barremian–Coniacian) of the Larsen Basin. This new record confirs that the Larsen Basin extends over southern Tabarin Peninsula, where basin sediments are thought to be faulted against sediments of the Antarctic Peninsula magmatic arc.

Landforms of Marine Plain in the Vestfold Hills contrast with those of most in the Vestfold Hills. They include consistent land surfaces at 40+ m and 25 m, characteristics controlled by orientation of rock features, and imprints of phases of glaciation, deglaciation and marine and freshwater inundation. The 40+ m surface is widespread in the Vestfold Hills and has been noted previously. The 25 m level was an earlier coastline, is more localized and marked by water rounded boulders; it serves to differentiate clearly between two terrains of different relief and erratic distribution. The Pliocene sedimentary rocks below the 25 m level have been dislocated, probably during an interval of glaciotectonism caused by northward movement of sediments under an ice load due to northern extension of the Sørsdal Glacier or expansion of the East Antarctic Ice Sheet some time after the mid-Pliocene. Soil development is active. These features are accompanied by the normal aspects of a glaciated landscape such as glacial striations, sand wedges, erratics, and patterned ground. Wind has been important in transporting sand and developing honeycomb weathering on exposed rock faces.