The McMurdo Dry Valleys of Antarctica are the largest ice-free region on the continent. These valleys contain numerous water bodies that receive seasonal melt from glaciers. For forty years, research emphasis has been placed on the larger water bodies, the permanent ice-covered lakes. We present results from the first study describing the geochemistry of ponds in the higher elevations of Taylor Valley. Unlike the lakes at lower elevations, the landscape on which these ponds lie is among the oldest in Taylor Valley. These upland ponds wax and wane in size depending on the local climatic conditions, and their ionic concentrations and isotopic composition vary annually depending on the amount of meltwater generated and their hydrologic connectivity. This study evaluates the impact of changes in summer climate on the chemistry of these ponds. Although pond chemistry reflects the initial meltwater chemistry, dissolution and chemical weathering within the stream channels, and possibly permafrost fluid input, the primary control is the dilution effect of glacier melt during warmer summers. These processes lead to differences in solute concentrations and ionic ratios between ponds, despite their nearby proximity. The change in size of these ponds over time has important consequences on their geochemical behaviour and potential to provide water and solutes to the subsurface.

The McMurdo Dry Valleys are among the driest, coldest environments on Earth and are excellent analogues for the Martian northern plains. In preparation for the 2008 Phoenix Mars mission, we conducted an interdisciplinary investigation comparing the biological, mineralogical, chemical, and physical properties of wetter lower Taylor Valley (TV) soils to colder, drier University Valley (UV) soils. Our analyses were performed for each horizon from the surface to the ice table. In TV, clay-sized particle distribution and less abundant soluble salts both suggested vertical and possible horizontal transport by water, and microbial biomass was higher. Alteration of mica to short-order phyllosilicates suggested aqueous weathering. In UV, salts, clay-sized materials, and biomass were more abundant near the surface, suggesting minimal downward translocation by water. The presence of microorganisms in each horizon was established for the first time in an ultraxerous zone. Higher biomass numbers were seen near the surface and ice table, perhaps representing locally more clement environments. Currently, water activity is too low to support metabolism at the Phoenix site, but obliquity changes may produce higher temperatures and sufficient water activity to permit microbial growth, if the populations could survive long dormancy periods (∼106 years).

Sea ice microalgae actively contribute to the pool of dissolved organic matter (DOM) available for bacterial metabolism, but this link has historically relied on bulk correlations between chlorophyll a (a surrogate for algal biomass) and bacterial abundance. We incubated microbes from both the bottom (congelation layer) and surface brine region of Antarctic fast ice for nine days. Algal-derived DOM was manipulated by varying the duration of irradiance, restricting photosynthesis with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) or incubating in the dark. The bacterial response to changes in DOM availability was examined by performing cell counts, quantifying bacterial metabolic activity and examining community composition with denaturing gradient gel electrophoresis. The percentage of metabolically active bacteria was relatively low in the surface brine microcosm (10–20% of the bacterial community), the treatment with DCMU indirectly restricted bacterial growth and there was some evidence for changes in community structure. Metabolic activity was higher (35–69%) in the bottom ice microcosm, and while there was no variation in community structure, bacterial growth was restricted in the treatment with DCMU compared to the light/dark treatment. These results are considered preliminary, but provide a useful illustration of sea ice microbial dynamics beyond the use of ‘snapshot’ biomass correlations.

After an extended period of sporadic sightings of small numbers of king penguins at the Falkland Islands, they established themselves on Volunteer Point, situated at the north-east of the islands, by the late 1970s. By 1980, a small breeding population was present which yielded some 40 fledglings during that same year. Since 1991, the population has been monitored annually and the resulting fledgling counts analysed to assess population trends. The population demonstrated a significant increase over the past three decades, at about 10% per annum, with time explaining 75% of the variation in count data. The current population is estimated to be 720 breeding pairs. Despite several authors having alluded to the existence of a large colony of king penguins at the Falklands prior to human exploitation, we found no evidence in support of this. We furthermore found no evidence in the literature in support of exploitation for king penguin oil during the 19th century. Unlike at other breeding sites, increasing numbers of king penguins at the Falklands is consequently unlikely to be a recovery response following exploitation, but rather an indication of either increased immigration or of improved feeding conditions.

The Tristan klipfish, Bovichtus diacanthus, an endemic species at Tristan da Cunha Island was successfully aged using whole sagittal otoliths. The annulation pattern was clear, resulting in an alternating combination of opaque and translucent zones that form an annulus. Although sampling limitations did not allow direct validation of annual ring deposition, most otoliths showed a translucent edge, perhaps suggesting that the deposition of translucent zones is a synchronous process which takes place in winter coincident with the spawning season. The reliability of ageing methodology was supported by the good agreement between readings. The maximum age was estimated to be five years in females and four years in males. In order to increase the small number of direct readings, the length at age was back-calculated for each fish by fitting growth curves. The resulting growth of B.diacanthus was described by the von Bertalanffy growth model, as summarized by the following parameters: L∞ = 207.1 mm TL, k = 0.49 per year, and t0 = 0.04 years. The size at which 50% of the population spawns for the first time was c. 147 mm, corresponding to 2.5 years of age.

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.

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.

The recently inaugurated Belgian Princess Elisabeth Station has been built in the Sør Rondane Mountains (Dronning Maud Land). The construction site is situated close to the Utsteinen Nunatak (71°57′S, 23°20′E), on a granite ridge. Prior to the survey and construction activities, the site had been subject to limited or no direct human impacts. Therefore, a biological inventory has been started for future evaluations of human impacts in the area. This study presents the cyanobacterial diversity of ten samples from the Utsteinen ridge, the Utsteinen Nunatak in the vicinity of the station's site and the more distant Ketelersbreen Dry Valley. All samples were taken before the station was built and were studied by light microscopy and Denaturing Gradient Gel Electrophoresis. Two strains were also isolated. Two different phenol-based extraction methods, with and without detergent-based steps, were tested to improve the quality of molecular detection from these environmental samples. We observed high cyanobacterial diversity (ten morphotypes and 13 operational taxonomic units) in comparison to other Antarctic terrestrial locations and a widespread distribution pattern within the Sør Rondane Mountains area. This might reflect the habitat similarities and/or the easy local dispersal capabilities of microorganisms within the region. The high diversity and proportion of potential endemic (46%) operational taxonomic units, of which 23% were newly described, suggest that this area could have acted as a biological refuge during past glaciations.

Observations were made of water column chemistry in four Na-Cl dominated ponds on the McMurdo Ice Shelf from the end of January to early April in 2008. During that time the ponds went from ice-free to predominantly frozen, with only a small volume of residual hypoxic, saline liquid trapped at the base of each pond. Changes in the concentrations of inorganic solutes with time distinguished Na, Cl, Mg, K, SO4, As, U and Mn as ions and trace elements that behave mainly conservatively during freezing, from those which are affected by biological processes (removing HCO3) and the precipitation of mineral phases such as calcite (removing Ca and more HCO3). Dissolved Fe, Mo, Cu and Zn also show evidence of precipitation from the water column during freezing; geochemical speciation modelling predicts the formation of stable insoluble mineral phases such as Fe oxides and oxyhydroxides while conditions are oxic, and Fe-, Cu-, Mo- and Zn-sulphide minerals in the presence of H2S. Consequently, under winter conditions, residual liquid beneath the ice in such ponds is anticipated to be an anoxic Na-Cl brine with the capacity to develop high concentrations of toxic trace elements such as As and U.

Antarctic terrestrial ecosystems are not immune to the threat of biological invasions, and the urgent need for implementation of effective mitigation measures to minimize the risk has been highlighted. Recently, the transportation and logistic support system of the Japanese Antarctic Research Expedition has undergone substantial changes after the relocation of the cargo handling facility and the commissioning of a new icebreaker in 2009. The potential risk of introducing non-native species into Antarctica through the newly adopted cargo transportation system in comparison with the previously existing system was determined by quantifying both changes in the form of cargo transported and the frequency of propagule attachment on different types of cargo item. We obtained 1022 propagules of at least 26 species, including species known to have resistance to the stresses of cold environments. Larger numbers of propagules, and a greater proportion of affected cargo items, were encountered in the newly adopted transportation system than in its predecessor. The increased risks in the new system were identified as being associated with the major cargo packing type and the cargo storage location. Based upon those findings, we propose appropriate preventative measures in order to minimize the risk of transfer of non-native species into Antarctica.

Although spiders are a diverse and ecologically important group of predators across the sub-Antarctic islands, relatively little is known about their biology. Here we provide data on the abundance, body size variation and sex ratio of an indigenous spider, Myro kerguelenensis, across an altitudinal gradient on Marion Island. In so doing we test explicitly the hypotheses that density will decline with declining resource availability at higher elevations, and that a converse Bergmann body size cline will be found in this species. Density of M. kerguelenensis decreased with altitude and ranged from a mean density of 5.3 (SD 3.42) individuals per m2 at 50 m a.s.l. to a mean density of 0.83 (SD 1.15) individuals per m2 at 600 m a.s.l. Mean female sternum width was 1.39 mm (SD 0.44) and mean male sternum width was 1.40 mm (SD 0.22). No evidence for Bergmann or converse Bergmann clines was found. At increasing altitudes, sex ratios became increasingly female-biased with populations at 600 m a.s.l. comprising 0.87 (SD 0.28) females, on a proportional basis, possibly as a result of resource limitation and an increase in the prevalence of sexual cannibalism. The food web implications of this study are highlighted.

Echinoderms are well represented in nearshore hard-bottom (< 100 m depth) habitats along the Antarctic Peninsula where they are presumably important contributors to benthic production, carbon flow, and determinants of community structure. The present study assesses the densities of echinoderms at shallow depths (2–15 m) at five sampling sites within three kilometres of Anvers Island on the central western Antarctic Peninsula. The asteroids Odontaster validus, Granaster nutrix, Lysasterias perrieri and Adelasterias papillosa, two ophiuroids in the Amphiuridae, the holothuroids Psolicrux coatsi and Psolus carolineae and one representative of the Cucumaridae, and the regular echinoid Sterechinus neumayeri were enumerated. Mean total echinoderm densities were high (34.9 individuals m-2) and ranged from 21.9 individuals m-2 for asteroids to 2.7 individuals m-2 for holothuroids. With the exception of a positive relationship between the abundance of the regular echinoid Sterechinus neumayeri and the biomass of the brown alga Himanthothallus grandifolius, no significant relationships were found between the abundance of asteroids, ophiuroids, or holothuroids and two species of brown algae or three algal ecotypes. The present study indicates nearshore hard-bottom echinoderms are important in the carbon cycle and their inherent vulnerability to ocean acidification may have community-level impacts.

The McMurdo Dry Valley lakes of Antarctica constitute some of the harshest and most isolated freshwater environments on Earth which might be expected to limit the biogeographical expansion of many organisms. Despite this, we found that the biodiversity of rotifer zooplankton is the highest ever recorded on the Antarctic mainland. We identified in total nine rotifer taxa, of which six are new to the Antarctic continent, in Lake Hoare, and also the first sub-adult crustacean copepod belonging to the genus Boeckella. A possible explanation for the high biodiversity is that many of the recorded species have arrived in the region in relatively recent times and then established invasive populations, suggesting that their distribution pattern was previously limited only by biogeographical borders. Interestingly, we show that the cosmopolitan rotifer taxa identified are relatively abundant, suggesting that they have established viable populations. Hence, our study suggests that the biogeographical maps have to be redrawn for several species.

We describe the habitat use of 22 male southern elephant seals (Mirounga leonina) satellite tagged at Marion Island between 2004 and 2008. While a few areas of increased utilization appeared to be associated with areas of shallower bathymetry (such as sea-floor ridges and fracture zones), seals in our study did not target other areas of shallow bathymetry within close proximity to Marion Island. Rather, most elephant seals foraged pelagically over very deep water where much variation was evident in diel vertical migration strategies. These strategies resulted in generally deeper and longer dives than what has been reported for male elephant seals from other colonies. No significant differences were recorded for dive durations or dive depths between adults and sub-adults. However, younger animals displayed a positive relationship between dive durations and age, as well as between dive depths and age, while these relationships became negative for older animals. Mixed model outputs suggested that seals increased their aerobic fitness as migrations progressed, enabling them to undertake longer dives. We conclude that Marion Island male elephant seals exhibit much variability in dive strategy and are seemingly capable of exploiting a range of different prey types occurring in various depth layers.