Diatom and water chemistry samples were collected from 49 lakes, pools and rivers on Byers Peninsula (Livingston Island, South Shetland Islands) during the summer of 2009. A diverse diatom flora of 143 taxa was found. Fragilaria capucina s.l., Psammothidium papilio, Navicula dobrinatemniskovae and several Nitzschia taxa dominated the flora. The biogeographical analysis showed that more than 55% of all observed taxa presented a restricted Antarctic biogeographic distribution and only 30% had a cosmopolitan distribution, contrary to previously published data. Cluster analysis and Principal Components Analysis were used to classify the samples based on their chemical characteristics, revealing that nutrients and specific conductance were the main factors dividing the samples into four groups: young lakes, coastal lakes, larger lakes on the central plateau and smaller, temporary pools. Diatom communities corresponded well to this division and were strongly influenced by salinity and nutrients.

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.

Possible effects of “El Niño” Southern Oscillation (ENSO) components “El Niño”and “La Niña“ on populations of southern elephant seals, Mirounga leonina L., are considered in this study. Information on pup weaning mass, collected at King George Island, South Shetland Islands, over a ten-year period (1985–94) was analysed with respect to the occurrence of ENSO and recent research in feeding ecology of this population in the Bellinghausen Sea. Weaning mass of elephant seals was found to be higher during “La Niña” and a lower during “El Niño”. Differences in weaning mass between sexes varied in different proportions during El Niño and La Niña. The teleconnection between tropical Pacific anomalies and the Bellinghausen Sea deserves further research, and our results suggest a way to study this phenomenon using data of elephant seal pups weaning mass as indicators of changes in food availability.

An investigation into the feeding habits of two demersal nototheniids, Trematomus bernacchii and T. centronotus, showed that the most important prey were polychaetes, molluscs and euphausiids for T. bernacchii and polychaetes and amphipods for T. centronotus. Epifaunal (e.g. Barrukia cristata) and tube-dwelling polychaetes (Amphicteis cfr. midas and Amythas membranifera) were common in the diet of both species. Bivalvia including Adamussium colbecki were found in the diet of T. bernacchii. Epifaunal gastropods (Trochidae) were an occasional prey for T. centronotus. Amphipods (mainly Acanthonotozomatidae) and the euphausiid Euphausia frigida were the main crustacean food of T. centronotus and T. bernacchii respectively. Our data suggest a difference in the feeding behaviour of the two nototheniid species, although both appear capable of feeding on common epibenthic invertebrates.

A mathematical model was used to simulate interannual patterns of biomass accumulation within benthic microbial mats of two Antarctic lakes. Lakes Hoare and Vanda are in the Dry Valley region of Southern Victoria Land, and are both perennially ice covered. The model combines experimentally derived observations of light/photosynthesis relationships and rates of respiration of mats from a range of depths in these lakes, with data on incident radiation and the optical properties of the ice and water column. The model was used to estimate daily and annual production and, using measured carbon content, the potential vertical accumulation of the mats over a year. An annual pattern of photosynthesis was predicted for both lakes, with net production from October to February and net respiration at other times. Predicted rates and patterns of net photosynthesis were remarkably similar in the two lakes, despite differences in light climate: the ice of Lake Hoare transmits 1–4% incident radiation, whereas that of Lake Vanda transmits up to 20%. Maximum daily rates of 15–20 μg carbon cm−2 were predicted to occur at approximately 10 m depth in both lakes. Maximum annual rates of carbon fixation (at 10–12 m depth) in both lakes were c. 1.2 mg carbon cm−2 equating to approximately 0.1–4 mm vertical accumulation of mat each year. Experimental studies of microbial mats in the lakes revealed horizontal laminations of similar thickness to model estimates, supporting the hypothesis that these were annual layers. Differences between model estimates and observations were found in deeper water in Lake Vanda, where considerably more material accumulated than was predicted.

The vertical distribution, abundance, population structure and life cycle of the ice-associated copepod, Paralabidocera antarctica was studied in the fast ice near Syowa Station (69°00'S, 39°35'E) in the eastern part of Lützow-Holm Bay in 1970, 1975 and 1982. The results indicated that P. antarctica inhabited the ice-seawater interface throughout the year with a one year life cycle and was actually present in the sea ice for most of the year except the summer. P. antarctica overwintered as naupliar stages (NIV-NV) with slow development in sea ice during winter. P. antarctica population then developed rapidly and attained adulthood in the water just beneath the sea ice during spring-summer. P. antarctica depended entirely on ice algae for food throughout its whole life-span, suggesting that the ice-seawater interface provides favourable food conditions for P. antarctica. The slow development in naupliar stages in sea ice and short copepodite life span in the water suggest that P. antarctica may adapt its growth strategy to suit the varying fast ice/water interface environment.

Most of the species in the Ectemnorhinin are cryptogam feeders, angiosperm feeders representing a minority. It is hypothesized that this dearth of angiosperm feeders is due to previous climatic conditions, which precluded angiosperm herbivory, but allowed for the exploitation of a diverse cryptogamic flora, and that only with the post-glacial warm-up of the Subantarctic has angiosperm herbivory become possible. When examined in the light of the Quaternary history of the South Indian Ocean Province islands, evidence obtained from a study of the habitat use, diet and morphology of species within the tribe supports this hypothesis.

The consumption of Antarctic krill (Euphausia superba) by an “average-sized” (male 6994 kg; female 8249 kg), sexually mature Minke whale (Balaenoptera acutorostrata) was estimated, from stomach capacity, ingestion rate and respiratory allometry methods. Estimates obtained from the stomach capacity and respiratory allometry methods differed by 17%–23%. An “average-sized” male Minke whale consumes 37.2 t of krill during a 90-day stay, and an “average-sized” female Minke whale consumes 56.2 t of krill during a 120-day stay, in Antarctic waters during the austral summer. It is estimated that the Minke whale population in the Antarctic (60°S and higher) consumes 35.5 × 106 t of krill annually.

We have examined information on the shape and size of Antarctic icebergs as derived from the ship data archive of Arctic and Antarctic Research Institute. The data in the archive cover the period from 1957–2009. For each of five major iceberg shapes we have established their relative frequency of occurrence in the Southern Ocean and the frequency distribution of the iceberg length and freeboard. Weathered and tabular icebergs were observed most often and comprised 66.9% and 22.6% of all reported icebergs respectively. Sloping, pinnacle, and dome icebergs represented correspondingly only 5.6%, 3.2% and 1.7% of the total number of icebergs observed. A distinct maximum was found in frequency distributions of the iceberg length and freeboard for all iceberg shapes. The most frequently observed iceberg lengths (modal length) ranged from 100–200 m for weathered and pinnacled icebergs to 400–600 m for tabular and dome-shaped iceberg. The modal freeboard of icebergs changed from 30–40 m for tabular and weathered icebergs to 50–60 m for domed, pinnacle and sloping icebergs. To calculate the overall mean size parameters of Antarctic icebergs we totalled corresponding mean values for each iceberg shape weighted by the frequency of occurrence of icebergs of each shape. The mean iceberg length and the standard deviation obtained within this approach were correspondingly 381 m and 349 m. The mean iceberg freeboard was equal to 41.2 m with a standard deviation of 12.1 m.

Megafloral remains recovered from the Jetty Member and the upper part of the Flagstone Bench Formation, Amery Group include Dicroidium and Pagiophyllum. Dicroidium zuberi and D. crassinervis forma stelznerianum occur with Pteruchus dubius and support a Mid to Late Triassic age. A new species of conifer, Pagiophyllum papillatus, is recognized along with an undetermined conifer pollen cone.

The summer of 1997 was characterized by unusually large amounts of pack ice in the southeastern Weddell Sea, and less than 10% of the area that is commonly ice-free in summer was open. A modest phytoplankton bloom developed in the upper mixed layer in the northernmost area (72°S). The bloom peaked in mid-February with max chlorophyll concentrations of 1.5 μg l−1, and integrated stocks of 55–60 mg m−2. Autotrophic flagellates dominated the biomass (80–90% of the chlorophyll) at first, while diatoms increased relative to flagellates during the bloom. Nutrient deficits, however, indicated that a much larger biomass was produced than was observed. Freezing starting after mid-February probably terminated the bloom, resulting in a pelagic growth season limited in time (less than two months) and space. The sea ice had a distinct brown layer of algae, usually at 1–2 m depth, with average chlorophyll biomass of 10.3 mg m−2. The ice cover exhibited a substantial amount of ridges, with ice algae growing in cavities and other structures, but with lower biomass than in the bands. Ice algae were also found growing on the lower 2 m of the ice shelf (visible at low tide). The overall growth season in the ice lasted several months, and ice algal production may have exceeded pelagic production in the Weddell Sea during the growth season of 1997. Pennate diatoms, like Fragilariopsis curta and F. cylindrus, dominated both in ice and in open water above the pycnocline, while Phaeocystis antarctica dominated in deeper layers and in crack pools. Euphausiids, particularly young stages, were frequently observed grazing on ice algae in ridges and on all sides of the floes, (confirmed by the gut content). Ice algae would thus have served as an ample food supply for the krill in the summer of 1997.

Solidified stomach oil deposits in snow petrel colonies in the Antarctic proved to be suitable for 14C dating and provide important palaeobiogeographical and palaeoenvironmental information. Following earlier studies in the Untersee oasis (Central Dronning Maud Land) we present here 14C measurements on comparable deposits from the Bunger Hills (66°10′S, 101°E). The conventional 14C age of the basal layer reflects the occupation age of any particular nesting site and therefore a minimum age for the time when this area became ice-free. According to the 14C results the occupation of the southern part of the Bunger Hills by petrels started about 10000yr ago. The breeding colonies expanded continuously following local ice retreat. The most intensive phases of colonization seem to have been from 8–6 kyr BP and during the past 2 kyr.

Marinobacter sp. W1-16 from Antarctic surface seawater was analysed for the production of extracellular polymeric substances (EPSs). Enhancement of the EPS biosynthesis was carried out by evaluating the influences of the carbon source (type and concentration), temperature, pH and salinity. EPS yields varied strongly depending on sugar substrate and temperature, while pH and salinity did not strongly affect levels of EPS production. Marinobacter sp. W1-16 produced the highest quantity of EPSs when growing at 15°C and pH 8, in the presence of 2% glucose and 3% NaCl. The EPS chemical characterization revealed a molecular weight of about 260 kDa. Colorimetric assays determined a higher quantity of carbohydrate than of proteins and uronic acids, as well as the presence of sulphate, in the extracted EPSs. The monosaccharidic composition resulted in Glc:Man:Gal:GalN:GalA:GlcA in relative molar proportions of 1:0.9:0.2:0.1:0.1:0.01. Some biotechnological potentialities (i.e. emulsifying and cryoprotective actions, and heavy metal binding properties) of the EPSs were proved, suggesting possible industrial and bioremediation applications.

The spiny plunder-fish, Harpagifer antarcticus, is a common shallow-water demersal species distributed along the southern limb of the Scotia Arc. A year round study was made of its reproductive biology at Signy Island, South Orkney Islands, for comparison with populations from the Antarctic Peninsula and with H. georgianus at South Georgia. Adult H. antarcticus inhabit rubble substrata and spawn 300–1500 eggs into a nest during May/July. The nest is guarded by both male and female fish during an incubation period of up to 150 days. After hatching during November/December the larvae grow at a rate of 0.082 mm d−1 (summer), 0.049 mm d−1 (winter) and 0.067 mm d−1 (annual), calculated from a time-series of samples collected from the field. This rate of growth is slow even among Antarctic species but is similar to the closely related species H. georgianus. Adult male and female H. antarcticus at the South Orkney Islands attain a maximum standard length of 88 mm and 85 mm respectively.

Although predictions suggest that ocean acidification will significantly impact polar oceans within 20–30 years, there is limited information regarding present-day pH dynamics of the Southern Ocean. Here, we present novel high-frequency observations of pH collected during spring of 2010 using SeaFET pH sensors at three locations under fast sea ice in the southern Ross Sea. During these deployments in McMurdo Sound, baseline pH ranged between 8.019–8.045, with low to moderate overall variation (0.043–0.114 units) on the scale of hours to days. The variation was predominantly in the direction of increased pH relative to baseline observations. Estimates of aragonite saturation state (ΩAr) were > 1 with no observations of subsaturation. Time series records such as these are significant to the Antarctic science community; this information can be leveraged towards framing more environmentally relevant laboratory experiments aimed at assessing the vulnerability of Antarctic species to ocean acidification. In addition, increased spatial and temporal coverage of pH datasets may reveal ecologically significant patterns. Specifically, whether such variation in natural ocean pH dynamics may drive local adaptation to pH variation or provide refugia for populations of marine calcifiers in a future, acidifying ocean.

Abundance and grazing impacts of krill, salps and herbivorous copepods were investigated in Antarctic waters along the 140°E meridian, south of Australia, during the summers of 2002 and 2003. North of the Southern Boundary of the Antarctic Circumpolar Current (SB-ACC), macrozooplankton comprised species of Salpa thompsoni and large herbivorous copepods, while the area south of the SB-ACC was numerically dominated by Euphausia superba or E. crystallorophias. North of the SB-ACC, the estimate of grazing impact revealed that krill, salps and copepods, Calanoides acutus, Calanus propinquus, Rhincalanus gigas and Metridia gerlachei, are able to remove a maximum of 37% of the total phytoplankton standing stock in early to midsummer, but grazing is negligible in late summer. The high grazing impact is attributed to the relatively high zooplankton abundance and low phytoplankton abundance. South of the SB-ACC, overall daily grazing impact of the three zooplankton groups was low and did not exceed 6% of the total phytoplankton standing stock throughout the investigation period. Present results indicate that the contribution of krill, salps and copepods varies seasonally as well as regionally across the SB-ACC. It seems that the carbon transport from surface to deep water by macro- and mesozooplankton in summer in this area is relatively large north of the SB-ACC but small south of the SB-ACC.

Carbon dating of basal peat deposits in Cumberland Bay and Stromness Bay and sediments from a lake in Stromness Bay, South Georgia indicates deglaciation at the very beginning of the Holocene before c. 9500 14C yr BP. This post-dates the deglaciation of one local lake which has been ice-free since at least 15 700 14C yr BP on account of its atypical geomorphological location. The latter indicates the likely presence of floristic refugia on South Georgia during the Last Glacial Maximum from which newly exposed terrestrial and aquatic habitats were rapidly colonized.

Shelf and slope cryptofauna were sampled at the most northerly shelf environments within the Southern Ocean, Shag Rocks. The area is remarkably rich, with seven phyla, 10 classes, 40 families and 81 species on 0.36 m2 of shelf boulders. A large proportion of genera and species found had not been seen there before, some were new to science and species accumulation curves did not approach an asymptote. Current estimates of benthic diversity are clearly still too low if even well studied locations and depths reveal so much novelty with such little sample effort. Proportions of new species were higher in slope samples showing how little we know of this important depth. Significantly, life was just as rich and, surprisingly, abundant on boulders from continental slope depths. Clearly there are places where the continental slope around Antarctica harbours a wealth of species with potential to resupply the shelf if life was ‘bulldozed’ off it by past ice shelf expansions during glacial maxima. Some species on boulders from 1500 m also occur as shallow as the Antarctic intertidal zone. That this rich fauna was ‘Antarctic’ in character shows the extremes, e.g. sea temperature (> 4°C in summer), that they can adapt to given long enough time periods.