The emperor penguin (Aptenodytes forsteri) is extremely dependent on the extent and stability of sea ice, which may make the species particularly susceptible to environmental change. In order to appraise the stability of the emperor penguin populations at six colonies in the western Ross Sea, we used linear regression analysis to evaluate chick abundance trends (1983–2005) and Pearson's r correlation to assess their relation to two local and two large-scale climate variables. We detected only one significant abundance trend; the Cape Roget colony increased from 1983 to 1996 (n = 6). Higher coefficients of variation in chick abundances at smaller colonies (Cape Crozier, Beaufort Island, Franklin Island) suggest that such colonies occupy marginal habitat, and are more susceptible to environmental change. We determined chick abundance to be most often correlated with local Ross Sea climate variables (sea ice extent and sea surface temperature), but not in consistent patterns across the colonies. We propose that chick abundance is most impacted by fine scale sea ice extent and local weather events, which are best evaluated by on-site assessments. We did not find sufficient evidence to reject the hypothesis that the overall emperor penguin population in the Ross Sea was stable during this period.

This investigation was motivated by the lack of ultraviolet radiation (UVR, 280–400 nm) studies on Antarctic benthic marine microalgae. The objective was to estimate the impact of UV-B (280–315 nm) and UV-A (315–400 nm), on photosynthetic efficiency, species composition, cell density and specific growth rate in a semi-natural soft-bottom diatom community. In both experiments, cell density increased over time. The most frequently observed species were Navicula cancellata, Cylindrotheca closterium, Nitzschia spp., and Petroneis plagiostoma. For both experiments, a shift in species composition and a decreased photosystem II (PSII) maximum efficiency (Fv/Fm) over time was observed, irrespective of treatment. UVR significantly reduced Fv/Fm on days 3 and 10 (Expt 1), disappearing on the last sampling date. A similar trend was found in Expt 2. A significant UV effect on cell density was observed in Expt 1 (day 10) but not in Expt 2. No treatment effects on species composition or specific growth rate were found. Thus, the UV effects were transient (photosynthetic efficiency and cell density) and the growth of the benthic diatoms was generally unaffected. Overall, according to our results, UVR does not seem to be a threat to benthic marine Antarctic diatoms.

Phytoliths in the modern vegetation of sub-Antarctic Campbell Island are compared with those in the soil beneath to assess the accuracy of vegetation reconstructions made from dispersed phytolith assemblages. The soil phytoliths alone suggest the source vegetation is a grassland association for all study sites, which reflects none of the herb, fern or shrub component of the overlying vegetation. It is concluded that at this locality dispersed phytoliths on their own are not reliable indicators of source vegetation and should be used with caution in this context for palaeoecological studies. However, they can provide useful botanical information where all other organic material is absent. With further research, based on the abundance and diversity of Poaceae phytoliths observed in this and other studies, dispersed phytoliths from the fossil record have the potential to contribute significantly to the understanding of grassland ecosystem development in the geological past.

A cadmium (Cd)-binding protein was isolated and characterized from the Antarctic clam Laternula elliptica after experimental exposure to a high concentration of Cd. Cd-binding metallothioneins (MTs) in the cytosol were purified using a procedure based on gel permeation and ion-exchange chromatography. The purified MTs were recognized by MT antibodies in a Western blotting assay. MALDI-TOF MS analyses showed that the molecular mass of the purified MTs was 7.27 kDa, which is typical of MTs found in marine invertebrates. The Cd binding to MT, reflected by the redistribution of Cd ions, was monitored by spectrophotometry. The absorption spectra profiles indicated the presence of Cd-MT complexes, and a 4 nm red shift of the unresolved lowest energy-absorption band occurred when five equivalents of Cd (II) were incorporated.

In an attempt to improve the understanding of the natural variability and distribution of trace elements in Antarctic organisms, the concentrations of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, vanadium and zinc in representative benthic species from two pristine coastal environments were measured and compared with literature data for other uncontaminated coastal ecosystems. Correlations between the elements, differences between the species and between the sampling sites were examined by principal component analysis. Metal accumulation was particularly evident in the tissues of the sea star Odontaster validus, the bivalve mollusc Laternula elliptica and in the red alga Phyllophora antarctica. However, metal accumulation was not the same for all the analytes, but, rather, depended on the organism characteristics. In particular, the soft tissues of Odontaster validus were characterized by high concentrations of cadmium, zinc and copper, those of Phyllophora antarctica by high concentrations of manganese and nickel, and the tissues of Laternula elliptica by high concentrations of all measured elements, particularly in its digestive gland. The Antarctic data as well as those reported for other pristine coastal ecosystems showed remarkably high natural variability in metal content, which must be taken into account when interpreting results from biomonitoring programmes.

Limited sampling has so far been conducted of the meroplankton community of the high Antarctic, with most research being conducted using vertical hauls in waters > 50 m, and little focused research on the meroplankton community directly under the sea ice (cryopelagic). Here we report the composition of the early summer cryopelagic meroplankton community of the shallow waters of Gerlache Inlet, Terra Nova Bay. A fixed-frame stationary plankton net was deployed c. 1 m below the annual sea ice and sampled at c. 24 hour intervals over a period of 19 days from mid-November to early December 2006. A total of 173 larvae from the phyla Annelida (n = 66), Mollusca (n = 30), Nemertea (n = 4), Echinodermata (n = 8), several Pleuragramma antarcticum (n = 4) and numerous planulae (n = 61) were collected, as well as 265 egg/embryo stages. A mean of 9.1 larvae (SD = 7.3, n = 19) and 13.9 eggs/embryos (SD = 20.5, n = 19) were found directly below the sea ice in each 24 hour period, and these early life history stages may be subject to the hazards of extensive platelet ice and penetrating ultraviolet radiation. The cryopelagic meroplankton community of shallow water is also compositionally similar to that of deeper waters, suggesting that the 50–0 m plankton tows used in previous research are providing a reliable assessment of the biodiversity of coastal Antarctic meroplankton.

Rock weathering plays an important role in soil development. A better understanding of how different temperature and moisture regimes impact on the rates of rock breakdown can thus contribute to our knowledge of how rates of soil production might be affected by changes in climate. Laboratory simulations using two temperature cycles determined from field data and three moisture levels were carried out on samples of granite from three locations along the Victoria Land coast. Estimates of weathering rate from these experiments were of the same order of magnitude as some other more field based studies undertaken in similar environments. However, actual values for samples from the three locations varied depending on the specific characteristics of the rock, especially grain size, porosity and extent of micro-cracking. Moisture availability was found to be an important factor in determining weight loss in the samples from Gneiss Point but not in those from Terra Nova Bay or Teall Island with the moderate level of moisture application having the greatest impact. Spring/autumn temperature cycles had a different effect on the breakdown of the rock samples compared to summer cycles but the magnitude of the effect was dependent on moisture level and rock characteristics, especially quartz content and the ability to absorb heat and moisture. The samples of rock from Terra Nova Bay and Gneiss Point where no moisture had been applied had significantly higher rates of breakdown under spring/autumn cycles than summer ones. However, this effect was reversed in the Gneiss Point samples after moisture was added. A future climate scenario using the weathering rates found in this research where there was, for example, a 10% increase in summer temperature cycles and a corresponding decrease in spring/autumn cycles predicted that a reduction in weathering would occur in conditions of little or no precipitation at Terra Nova Bay and Gneiss Point but there would be limited effect under higher levels of moisture.

We present the first study from the Bransfield Basin that extends through the Holocene, recording the variable climate history back to the decoupling of the ice sheet from the continental shelf ~10 650 calendar years before present (cal yr bp). Detailed sediment analysis reveals three stratigraphic units in PC-61 concomitant with three sedimentary environments, similar to sedimentary facies reported elsewhere: 1) subglacial, 2) glacial proximal/sub-ice shelf, and 3) open marine. These interpretations are based on a variety of sedimentological criteria, supported by ten AMS radiocarbon dates and detailed diatom analysis. We note two significant volcanic ash layers (tephra) at 3870 and 5500 cal yr bp from nearby Deception Island. Based on diatom assemblage analysis, we identify five separate climate regimes, highlighting a significantly shorter Mid-Holocene Climatic Optimum than reported by other studies (6800–5900 cal yr bp). This period is marked by the highest Eucampia antarctica var. antarctica and Fragilariopsis curta abundance, total diatom abundance, sediment accumulation rates, and low magnetic susceptibility. We also identify a less pronounced Neoglacial period relative to other studies, which includes an increase of Cocconeis/Rhizosolenia spp. assemblage related to unstable surface water conditions. Such observations probably reflect important regional variations in atmospheric or ocean circulation patterns.

We present 21Ne exposure ages of erosional glaciogenic rock surfaces on nunataks in northern Victoria Land, Antarctica: i) in the Prince Albert Mountains and ii) near Mesa Range. These nunataks are located directly at the margin of the polar plateau and therefore provide an immediate record of ice volume changes of the East Antarctic Ice Sheet, not biased by ice shelf grounding or narrow valley sections downstream the outlet glaciers. The sampling locations overlook the present ice surface by less than 200 m, but were last covered by ice 3.5 Ma bp (minimum age, not corrected for erosion). This strongly indicates that the ice sheet has not been substantially thicker than today since at least the early Pliocene, which supports the hypothesis of a stable East Antarctic Ice Sheet. First absolute ages are reported for the alpine topography above the erosive trimline that typically marks the upper limit of glacial activity in northern Victoria Land. Unexpectedly low nuclide concentrations suggest that erosion rates on the alpine topography are considerably higher due to the steep slopes than those affecting flat erosional surfaces carrying Antarctic tors.

Recently, the Antarctic Peninsula has received more attention due to the pronounced warming in that region. Non-glaciated coastal areas on the Peninsula can be significant energy sources for the atmosphere when they are exposed during summer despite the high degree of cloud associated with the frequent passage of low pressure systems. An eddy covariance system was established in December 2002 to evaluate the turbulent energy exchanges between the atmosphere and a non-glaciated coastal area on King George Island. Monthly average downward shortwave radiation was less than 210 Wm-2 in summer. Due to the low albedo of 0.12, monthly average net radiation reached > 130 Wm-2, a magnitude that was significantly larger than the reported magnitudes of < ~70 Wm-2 at glaciated areas with a high albedo on the Peninsula. The sum of monthly average sensible heat (< 64 Wm-2) and latent heat (< 20 Wm-2) fluxes amounted up to ~80 Wm-2, which was an order of magnitude larger than those at glaciated areas on the Antarctic Peninsula. Given that non-glaciated areas should be enlarged if the warming continues, more attention may need to be paid to the role of non-glaciated areas in the local climate to predict climate change on the Antarctic Peninsula.