Antarctic krill has been studied for many decades, but we are still long way from understanding their biology to be able to make reliable predictions about the reaction of their populations to environmental change. This is partly due to certain difficulties in relation to logistics, operations and survey design associated with scientific surveys that have been obstacles for us to better understand krill biology. The krill fishery is the largest fishery in the Southern Ocean, continuously operating since early 1970s. Recent studies revealed its potential to be used as a unique source for scientific discussions to understand krill biology. In this paper, after a brief overview of krill fishery operation and krill biology, we examine how current data collection through the fishery operation could contribute to a greater understanding of krill biology, and then suggest future priorities for fisheries-related research in relation to recent changes in the Southern Ocean environment.

A directional primary succession with moderate species replacement was quantitatively characterized on Signy Island in zones of a glacial valley corresponding to their age since deglaciation. A continuous increase in diversity and abundance of lichens and bryophytes was observed between terrains deglaciated in the late 20th century, to areas where deglaciation followed the Little Ice Age, and others thought to be ice-free since soon after the Last Glacial Maximum. Classification (UPGMA) and ordination (principal co-ordinate analysis) of vegetation data identified three different stages of development: a) pioneer communities, which rapidly develop in a few decades, b) immature communities developing on three to four century old terrains, and c) a climax stage (Polytrichum strictum-Chorisodontium aciphyllum community) developing on the oldest terrains, but only where local-scale environmental features are more favourable. Multivariate analysis including environmental parameters (canonical correspondence analysis) indicated terrain age as being the dominant controlling factor, with other environmental factors also exhibiting significant conditional effects (duration of snow cover, surface stoniness). These findings not only quantitatively verify reports of the rapid colonization of Maritime Antarctic terrains following recent climate amelioration and associated decrease in glacial extent, but also show how local-scale environmental resistance may slow or even prevent vegetation succession from pioneer to more mature stages in future.

Globally, areas categorically known to be free of human visitation are rare, but still exist in Antarctica. Such areas may be among the most pristine locations remaining on Earth and, therefore, be valuable as baselines for future comparisons with localities impacted by human activities, and as sites preserved for scientific research using increasingly sophisticated future technologies. Nevertheless, unvisited areas are becoming increasingly rare as the human footprint expands in Antarctica. Therefore, an understanding of historical and contemporary levels of visitation at locations across Antarctica is essential to a) estimate likely cumulative environmental impact, b) identify regions that may have been impacted by non-native species introductions, and c) inform the future designation of protected areas under the Antarctic Treaty System. Currently, records of Antarctic tourist visits exist, but little detailed information is readily available on the spatial and temporal distribution of national governmental programme activities in Antarctica. Here we describe methods to fulfil this need. Using information within field reports and archive and science databases pertaining to the activities of the United Kingdom as an illustration, we describe the history and trends in its operational footprint in the Antarctic Peninsula since c. 1944. Based on this illustration, we suggest that these methodologies could be applied productively more generally.

The organic carbon particle export to the interior layers in the Southern Ocean in the New Zealand–Tasmania Sector was approximately 170 mmolC m−2 yr−1. The export of particulate inorganic carbon in CaCO3 was 110 mmolC m−2 yr−1 and was contributed mostly by pteropods shells in the Antarctic Zones. The Si flux from biogenic opal at the sub-Antarctic Zone was 67 mmolSi m−2 yr−1 and rapidly increased to the south up to nearly 1 molSi m−2 yr−1 in the Antarctic Zone. The Antarctic Polar Front clearly demarcated the area where the biological pump was driven by CaCO3 to the north and biogenic SiO2 particle export to the south. Summer stratification caused by the sub-zero winter water layer in the Seasonal Ice Zone (SIZ) curtails the zooplankton community and hinders the replenishment of Fe. This hypothesis explains the large organic carbon export with large f- and export ratios at the SIZ and extremely large opal production at the Antarctic Circumpolar Zone. Estimated regeneration rate of CO2 from the export production and settling particulate fluxes of organic carbon in the water column between 100 m to 1 km was about 13 mmolC m−2 d−1 in the Antarctic Zone and Polar Frontal Zone.

Using archival photography and satellite imagery, we have analysed the rates of advance or retreat of 103 coastal glaciers on South Georgia from the 1950s to the present. Ninety-seven percent of these glaciers have retreated over the period for which observations are available. The average rate of retreat has increased from 8 Ma-1 in the 1950s to 35 Ma-1 at present. The largest retreats have all taken place along the north-east coast, where retreat rates have increased to an average of 60 Ma-1 at present, but those on the south-west coast have also been steadily retreating since the 1950s. These data, along with environmental information about South Georgia, are included in a new Geographic Information System (GIS) of the island. By combining glacier change data with the present distribution of both endemic and invasive species we have identified areas where there is an increased risk of rat invasion to unoccupied coastal regions that are currently protected by glacial barriers. This risk has significant implications for the surrounding ecosystem, in particular depletion in numbers of important breeding populations of ground-nesting birds on the island.

We report evidence of a large proglacial lake (Glacial Lake Wright) that existed in Wright Valley in the McMurdo Dry Valleys region of Antarctica at the last glacial maximum (LGM) and in the early Holocene. At its highstands, Glacial Lake Wright would have stretched 50 km and covered c. 210 km2. Chronology for lake-level changes comes from 30 AMS radiocarbon dates of lacustrine algae preserved in deltas, shorelines, and glaciolacustrine deposits that extend up to 480 m above present-day lakes. Emerging evidence suggests that Glacial Lake Wright was only one of a series of large lakes to occupy the McMurdo Dry Valleys and the valleys fronting the Royal Society Range at the LGM. Although the cause of such high lake levels is not well understood, it is believed to relate to cool, dry conditions which produced fewer clouds, less snowfall, and greater amounts of absorbed radiation, leading to increased meltwater production.

Admiralty Bay on the King George Island hosts the Brazilian, Polish and Peruvian research stations as well as the American and Ecuadorian field stations. Human activities in this region require the use of fossil fuels as an energy source, thereby placing the region at risk of hydrocarbon contamination. Hydrocarbon monitoring was conducted on water and sediment samples from the bay over 15 years. Fluorescence spectroscopy was used for the analysis of total polycyclic aromatic hydrocarbons (PAHs) in seawater samples and gas chromatography with flame ionization and/or mass spectrometric detection was used to analyse individual n-alkanes and PAHs in sediment samples. The results revealed that most sites contaminated by these compounds are around the Brazilian and Polish research stations due to the intense human activities, mainly during the summer. Moreover, the sediments revealed the presence of hydrocarbons from different sources, suggesting a mixture of the direct input of oil or derivatives and derived from hydrocarbon combustion. A decrease in PAH concentrations occurred following improvement of the sewage treatment facilities at the Brazilian research station, indicating that the contribution from human waste may be significant.

Sixty-three radiocarbon dates on organic remains from 21 abandoned colonies of chinstrap (Pygoscelis antarctica) and Adélie (P. adeliae) penguins on 12 islands in the Antarctic Peninsula region are evaluated for determining the occupation history of penguins in this region. This record also provides a means for assessing sea-level change, glacial advances and retreats, and population responses by penguins to these events. All conventional dates were corrected for the marine-carbon reservoir effect by applying a ΔR = 700±50 BP and marine calibration curves. The 63 calibrated dates give 2σ ranges (95% confidence intervals) from modern to 5990 yr BP. These dates indicate progressively older occupations from north to south along the Antarctic Peninsula. No sites older than approximately 540 BP occur in the northern peninsula, either because they have not yet been found or older sites have been destroyed by solifluction and glacial scouring. Three dates from one locality near Rothera Point, Adelaide Island, also were calibrated with a ΔR = 750 ± 50 and 800 ± 50 BP. No difference was found between calibrated dates using these two other ΔR values, indicating that local corrections for variation in upwelling intensity may not be necessary.

We report ion-microprobe U-Pb zircon ages from charnockites of a large Proterozoic composite batholith, Mawson Coast, Australian Antarctic Territory. The charnockites crystallized from orogenic magmas of intermediate composition (mainly 54–68% SiO2) intruded into a granulite-facies metasedimentary gneiss sequence between the second and third recognized deformations. A sample of low-Ti charnockite provides an age of 954 ± 12 Ma and a high-Ti charnockite is dated at 985 ± 29 Ma (all ages quoted at 95% confidence). The age difference is not significant at the 95% confidence level. Both these ages were obtained from zircons with igneous zoning and/or morphology and thus are thought to date igneous crystallization. Zircons from a felsic gneiss xenolith within the charnockite have cores of various ages, many from 1.7 to 2.0 Ga, but with other grains between 1.0 and 1.5 Ga and a single 2.5 Ga zircon. These zircon cores are direct evidence for an early to middle Proterozoic age for the supracrustal basement sequence in this mobile belt. Many of these zircon cores are concordant but abundant discordant grains suggest a complex history of multiple Pb-loss events. Zircon rims grew at 921 ± 19 Ma, probably during the post-charnockite deformation (D3). Previously obtained Rb-Sr dates for charnockite of 886 ± 48 Ma and 910 ± 18 Ma were probably also rest during D3. A Rb-Sr isochron date of 1061 ± 36 Ma previously reported for high-Ti charnockite from Mawson Rock is thought to be erroneous, and a new date of 959 ± 58 Ma (consistent with both the igneous and reset dates above) is interpreted from those data.

Two new U-Pb zircon ages from the area immediately west of Denman Glacier in Antarctica show that its geological history differs from that of the Obruchev Hills and Bunger Hills, to the east of the glacier. A crystallization age of 516.0 ± 1.5 Ma for syenite is by far the youngest primary age reported for this region, whereas tonalitic orthogneiss from Cape Charcot, the oldest known local rock, was derived by the high-grade metamorphism and deformation at 2889 ± 9 Ma of a 3003 ± 8 Ma igneous precursor. Both major populations of zircon in this rock lost Pb at 500–600 Ma. Although the Sm-Nd characteristics of the entire region resemble those of the Albany Mobile Belt of Western Australia, the Sm-Nd systematics of the felsic gneisses and plutonics are too old to allow direct correlation with the rocks of the Naturaliste Block (Western Australia), a potential key element for Gondwana reconstruction. However, the possibility exists that there is an indirect relationship between the Naturaliste Block and the region immediately west of Denman Glacier.

Human activity and specifically tourism has been increasing in Antarctica over the last few years. Few studies have examined the indirect effects of human visits on Antarctic penguin rookeries. This work aims to study the differences between a highly visited (Hannah Point) and a rarely visited (Devil's Point, Byers Peninsula) gentoo penguin rookery on Livingston Island. Our results suggest that potential indirect effects of human impact are observed in gentoo penguins at Hannah Point, a colony heavily visited by tourists. Penguins at Hannah Point showed a higher presence of heavy metals such as Pb and Ni and a higher number of erythrocytic nuclear abnormalities than penguins at Devil's Point. Immunological parameters showed different results depending on whether we consider the cellular response - the number of lymphocytes being higher in penguins from Hannah Point - or the humoral response - the level of immunoglobulins being higher in penguins from Devil's Point. Measurements of corticosterone levels in feathers and heterophil/lymphocyte (H/L) ratio in blood showed lower levels in the heavily visited rookery than in the rarely visited rookery. Finally, we did not detect Campylobacter jejuni, a bacteria potentially transmitted by humans in either of the populations and we did not find any difference in the prevalence of Campylobacter lari between the populations.

According to the newest version of the US Soil Taxonomy permafrost-affected soils are Gelisols. Antarctic Gelisols in the cold deserts of the Ross Sea sector are formed under extreme conditions of low temperature and aridity. The main soil forming processes are oxidation and salinization, with almost complete absence of organic matter. The oldest soils date from around 13 Ma. The origin of most soil salts is atmospheric, linking these soils to those in other parts of the world through atmospheric processes. The soils have water contents in the active layer of the most arid areas <1%. With decreasing latitude or proximity to the coast in East Antarctica and the Antarctic Peninsula, soil water contents increase and the soils support a range of soil organisms and plant species. At latitudes ≤66°S organic matter accumulation and several other pedogenic processes such as cryoturbation, mineral weathering, brunification, acidification, podzolization and redoximorphism occur. In addition, these soils receive nitrogen and phosphorus from seabirds. In most places summer thaw lasts little more than six weeks; thaw depths range from around 10–100 cm. A critical factor in the soil development is the albedo of the soil surface, since the absorbed energy controls weathering processes. The extreme fragility of the soils in the arid Ross Sea sector is largely due to the absence of structure, cohesion, moisture and organic materials. Recovery from physical human disturbances is in the order of hundreds to thousands of years. In East Antarctica and the Antarctic Peninsula plant and organisms growth is similarly slow and ecosystems are susceptible to human impact. The occurrence of many old soils at high inland elevation indicates that little response to global climatic change would be expected there. For the much younger soils in East Antarctica and the Antarctic Peninsula, when mean annual summer temperatures are higher, responses to global change and change in sea level may be significant.

Using a previously derived treatment of viscoelastic flexure of floating ice shelves, we simulated multiple years of evolution of a single, axisymmetric supraglacial lake when it is subjected to annual fill/drain cycles. Our viscoelastic treatment follows the assumptions of the well-known thin-beam and thin-plate analysis but, crucially, also covers power-law creep rheology. As the ice-shelf surface does not completely return to its un-flexed position after a 1-year fill/drain cycle, the lake basin deepens with each successive cycle. This deepening process is significantly amplified when lake-bottom ablation is taken into account. We evaluate the timescale over which a typical lake reaches a sufficient depth such that ice-shelf fracture can occur well beyond the lake itself in response to lake filling/drainage. We show that, although this is unlikely during one fill/drain cycle, fracture is possible after multiple years assuming surface meltwater availability is unlimited. This extended zone of potential fracture implies that flexural stresses in response to a single lake filling/drainage event can cause neighbouring lakes to drain, which, in turn, can cause lakes farther afield to drain. Such self-stimulating behaviour may have accounted for the sudden, widespread appearance of a fracture system that drove the Larsen B Ice Shelf to break-up in 2002.

The arrival in January 2001 in the south-west Ross Sea of two giant icebergs, C16 and B15A, subsequently had dramatic affects on two emperor penguin colonies. B15A collided with the north-west tongue of the Ross Ice Shelf at Cape Crozier, Ross Island, in the following months and destroyed the penguins' nesting habitat. The colony totally failed in 2001, and years after, with the icebergs still in place, exhibited reduced production that ranged from 0 to 40% of the 1201 chicks produced in 2000. At Beaufort Island, 70 km NW of Crozier, chick production declined to 6% of the 2000 count by 2004. Collisions with the Ross Ice Shelf at Cape Crozier caused incubating adults to be crushed, trapped in ravines, or to abandon the colony and, since 2001, to occupy poorer habitat. The icebergs separated Beaufort Island from the Ross Sea Polynya, formerly an easy route to feeding and wintering areas. This episode has provided a glimpse of events which have probably occurred infrequently since the West Antarctic Ice Sheet began to retreat 12 000 years ago. The results allow assessment of recovery rates for one colony decimated by both adult and chick mortality, and the other colony by adult abandonment and chick mortality.

Laser-based Fourier-Transform Raman spectroscopy (FTRS) has been used to identify in situ compounds of ecophysiological significance in diverse field-fresh Antarctic cryptoendolithic microbial communities. FTRS does not disrupt the community and permits characterization of visible and invisible compounds in their natural configuration within cells and their current or former microhabitat. The small “footprint” of the microscopic laser beam permits accurate analysis of discrete zones of compounds produced by extant or degraded micro-organisms with minimum destruction of the biota. This spatial chemical analysis is applicable to any translucent or exposed habitat or biotic assemblage. Two hydrated forms of biodegradative calcium oxalate were differentiated in black-pigmented and hyaline lichen zones of endolithic communities. The oxalate was restricted to zones containing fungi. Communities dominated by cyanobacteria at Battleship Promontory (77°S) and a newly discovered site at Timber Peak (74°S) contrasted chemically with those dominated by eukaryotic algae at East Beacon (78°S). FTRS also showed the zonation of pigments including chlorophyll and UV-protective carotenoids in situ. At extreme sites on the polar plateau, it revealed the presence of “fossil” endolithics where detrimental climatic changes had made the microbes non-viable or amorphous, being represented solely by their residual bio-molecules. The technique has potential for past or present life-detection anywhere in the world without destruction of the microniche.

Maritime Antarctic freshwater lakes and their catchments are inherently simple systems in an environment which is characterized by strong seasonality. Such lakes offer excellent opportunities to study the interaction of water chemistry and plant communities. The response of diatom species to environmental gradients was assessed by constructing a diatom and water chemistry dataset from 59 lakes at two locations (Livingston Island, South Shetland Islands and Signy Island, South Orkney Islands). Results indicate that diatom species abundance is predominately related to nutrient and salinity gradients. The dataset will be used to create transfer functions which can be applied to sediment core diatom assemblages to reconstruct historical patterns of lake chemistry.

A survey of hydrocarbons and sterols in marine and shoreline sediments was undertaken adjacent to Davis Station in Princess Elizabeth Land, Prydz Bay, Eastern Antarctica to determine the impact of a human settlement, including a sewage outfall on the local marine environment. Soil samples from selected locations onshore were also analysed to ascertain the extent of hydrocarbon contamination emanating from fuel storage facilities and other potential sources. The faecal sterol coprostanol was detected at 13.2 μg g−1 (60% of total sterols) in sediment adjacent to the Davis sewage outfall and up to 5.0 μg g−1 on the shoreline at Davis Beach. These concentrations indicate significant faecal contamination. The absence of coprostanol in faeces from the local wildlife confirms a human origin for this sewage biomarker. Hydrocarbons on the shoreline near Davis were present at up to 5.5 μg g−1 (dry weight of sediment). Biomarker profiles indicate an anthropogenic origin for these hydrocarbons. Onshore, degraded hydrocarbons derived from Special Antarctic Blend distillate were found at relatively high levels in soils at the fuel storage depot (up to 220 μg g−1). The source of these hydrocarbons appeared to be spillage from fuel storage tanks with possible contributions from fuel pipeline leakage and vehicle useage. Concentrations of polycyclic aromatic hydrocarbons in the soils were very low, generally below 1 ng g−1 (dry weight of sediment) for individual compounds.

During RV Polarstern cruise ANT-XXIII/4 in 2006, a gravity core (PS 69/335-2) and a giant box core (PS 69/335-1) were retrieved from Maxwell Bay off King George Island (KGI). Comprehensive geochemical (bulk parameters, quantitative XRF, Inductively Coupled Plasma Mass Spectrometry) and radiometric dating analyses (14C, 210Pb) were performed on both cores. A comparison with geochemical data from local bedrock demonstrates a mostly detrital origin for the sediments, but also points to an overprint from changing bioproductivity in the overlying water column in addition to early diagenetic processes. Furthermore, ten tephra layers that were most probably derived from volcanic activity on Deception Island were identified. Variations in the vertical distribution of selected elements in Maxwell Bay sediments further indicate a shift in source rock provenance as a result of changing glacier extents during the past c. 1750 years that may be linked to the Little Ice Age and the Medieval Warm Period. Whereas no evidence for a significant increase in chemical weathering rates was found, 210Pb data revealed that mass accumulation rates in Maxwell Bay have almost tripled since the 1940s (0.66 g cm-2 yr-1 in ad 2006), which is probably linked to rapid glacier retreat in this region due to recent warming.

Moisture sources for snow falling in Dronning Maud Land (DML), Antarctica, are calculated for 1998 using three dimensional 5-days backward air parcel trajectories. The drilling site of the European Project on Ice Coring in Antarctica (EPICA) in DML is chosen as the main arrival point (75.0°S, 0.01°E). A distinction is made between trajectories with and without snowfall at arrival. Of the snowfall trajectories, 40–80% are located in the Atlantic Ocean within four days before arrival. Evaporation along these trajectories is largest three to four days before arrival. The air parcels are then located between 40° and 60°S in the Atlantic Ocean where surface temperatures range between 0° and 20°C. A case study for May 1998 shows that when snow falls exceptionally high temperatures and wind speeds prevail in the atmospheric boundary layer. The position of the trajectories in the boundary layer suggests a source region for this event between 40° and 50°S and 20° and 60°W in the Atlantic Ocean, where sea surface temperatures vary between 5° and 15°C.

The lipid composition of natural populations of diatoms in the sea ice at McMurdo Sound was determined during the austral spring bloom of 1985, using and Iatroscan TLC–FID system. The major lipid classes in all samples were polar lipids (including phospholipid, glycolipid and chlorophyll) and triacylglycerol, with lesser proportions of free fatty acids. Total lipid increased through November and early December, reaching a maximum (3300 mg m−2 at Cape Armitage and 1800 mg m−2 at Erebus Ice Tongue) c. one week after the chlorophyll a maxima. This increase was largely attributable to a corresponding increase in triacylglycerol. At the lipid maxima, triacylglycerol/polar lipid ratios in the range 1.0 to 2.5 were observed. The dynamic variations in lipid class abundances indicate that profound changes in the physiology of sea-ice diatoms are occurring throughout the spring bloom. A range of sterols (C26–C30) were detected; 24-methylenecholesterol, brassicasterol and 24-ethylcholesterol were the major sterols at the Cape Armitage and Erebus sites. The similarity of the sterol profiles to those of Antarctic freshwater algal communities strongly indicates diatoms as a more probable source of C29 sterols in the freshwater lakes than cyanobacteria or other algal groups. The hydrocarbons isolated from sea-ice diatoms at all sites were dominated by two unsaturated components, n−C21:6 and a diunsaturated isoprenoid C25 alkene. Until this study, no biological source had been validated for the isoprenoid C25:2 diene, even though it has been detected in many estuarine and coastal sediments.