This study contains the current list of the austral pycnogonids together with details of their depth range and distribution. To date 264 species have been recorded, accounting for 19.6% of the 1344 species recorded worldwide. One hundred and eight species are endemic to Antarctic waters, 62 to the sub-Antarctic, 63 are common in both regions, and 55 are circumpolar. The richest genus is Nymphon, with 67 species and the richest area is the Scotia Sea. Comparing species lists between the years 2000 and 2007 shows that increased expeditions with more sampling has increased the circumpolarity of species and decreased zonal endemicity. The benthic insular refuge hypothesis is proposed as an explanation for the southern distribution of the present pycnogonid fauna, with an origin in the Scotia Arc.

Adult male southern elephant seals instrumented in 2000 on King George Island (n = 13), travelled both to the north (n = 2) and to the east (n = 6) of the Antarctic Peninsula. Five males remained within 500 km of the island focusing movements in the Bransfield Strait and around the Antarctic Peninsula. Sea surface temperatures encountered by these animals showed little variation. While animal trajectories appeared unaffected by sea ice cover, areas of shallow depths were frequented. Three males moved as far as 75°S to the east of the Peninsula with maximum distances of more than 1500 km from King George Island. They travelled into the Weddell Sea along the western continental shelf break until they reached the region of the Filchner Trough outflow. Here the sea floor consists of canyons and ridges that support intensive mixing between the warm saline waters of the Weddell Gyre, the very cold outflow waters and ice shelf water at the Antarctic Slope Front. The need for re-instrumentation of adult males from King George Island is highlighted to investigate whether males continue to travel to similar areas and to obtain higher resolution data.

We investigated intraspecific geographic variation in buoyancy by obtaining percentage buoyancy (%B) measurements for the Antarctic notothenioid species Pleuragramma antarcticum, Trematomus hansoni, T. bernacchii and Gymnodraco acuticeps from both McMurdo Sound in East Antarctica and the South Shetland Islands in West Antarctica. Mean percentage buoyancies in these species ranged from 0.22–0.52% in the neutrally buoyant P. antarcticum to 3.34–3.67% in the benthic T. bernacchii. Dispersion (1 standard deviation) of percentage buoyancy (%B) values around the mean was ± 0.2–0.5 %B units for the entire sample. Although intraspecific differences in mean percentage buoyancy were statistically significant (P < 0.05) in P. antarcticum and T. hansoni, we consider these differences as normal variation without substantive biological significance. The dispersion in buoyancy measurements during adult life reflects the density of the fish and this may be influenced, in both the short- and long-term, by gut contents, nutritional condition, and reproductive state. Mitigation of the effects of these variables is not biologically realistic because they constitute normal aspects of the daily and yearly life cycles. The results of our measurements of buoyancy are consistent with what is known about the ecology of these four species and this is considered in the discussion.

During CHINARE-22 (December 2005–March 2006), we investigated six penguin colonies in the Vestfold Hills, East Antarctica, and collected several penguin ornithogenic sediment cores, samples of fresh guano and modern penguin bone and feather. We selected seven penguin bones and feathers and six sediments from the longest sediment core and performed AMS14C dating. The results indicate that penguins occupied the Vestfold Hills as early as 8500 calibrated years before present (cal. yr bp), following local deglaciation and the formation of the ice free area. This is the first report on the Holocene history of penguins in the Vestfold Hills. As in other areas of Antarctica, penguins occupied this area as soon as local ice retreated and the ice free area formed, and they are very sensitive to climatic and environmental changes. This work provides the foundation for understanding the history of penguins occupation in Vestfold Hills, East Antarctica.

The West Antarctic Peninsula region is an important source of Antarctic krill (Euphausia superba) in the Southern Ocean. From 1980–2004 abundance and concentration of phytoplankton and zooplankton, krill reproductive and recruitment success and seasonal sea ice extent here were significantly correlated with the atmospheric Southern Oscillation Index and exhibited three- to five-year frequencies characteristic of El Niño–Southern Oscillation (ENSO) variability. This linkage was associated with movements of the Southern Antarctic Circumpolar Current Front and Boundary, a changing influence of Antarctic Circumpolar Current and Weddell Sea waters, and eastward versus westward flow and mixing processes that are consistent with forcing by the Antarctic Dipole high-latitude climate mode. Identification of hydrographic processes underlying ecosystem variability presented here were derived primarily from multi-disciplinary data collected during 1990–2004, a period with relatively stable year-to-year sea ice conditions. These results differ from the overwhelming importance of seasonal sea ice development previously established using 1980–1996 data, a period marked by a major decrease in sea ice from the Antarctic Peninsula region in the late 1980s. These newer results reveal the more subtle consequences of ENSO variability on biological responses. They highlight the necessity of internally consistent long-term multidisciplinary datasets for understanding ecosystem variability and ultimately for establishing well-founded ecosystem management. Furthermore, natural environmental variability associated with interannual- and decadal-scale changes in ENSO forcing must be considered when assessing impacts of climate warming in the Antarctic Peninsula–Weddell Sea region.

The Antarctic Pearlwort, Colobanthus quitensis (Kunth.) Bartl. (Caryophyllaceae) is one of the two native vascular plant species that have successfully colonized the maritime Antarctic during the Holocene (Smith 1984). Within the Antarctic biome, it is only found on the Antarctic Peninsula and on islands in the maritime Antarctic (Smith 1984). Its distribution also includes South Georgia (sub-Antarctic), the Falkland Islands, and sites along the Andes, reaching c. 10°N in Mexico (Moore 1970). Moore (1970) observed that C. quitensis is self-compatible and appears to be largely, if not entirely, self-pollinated. Convey (1996), found that maritime Antarctic C. quitensis showed lower allocation to seed production than plants from sub-Antarctic sites.

Ixodes uriae White is the only tick species found in Antarctica, and in our research area at Palmer Station it feeds predominantly on Adélie penguins. At the beginning of the summer the ticks leave their off-host aggregation sites, feed on penguins, then subsequently return to their off-host habitats, where they remain until the next summer (Benoit et al. 2007). These ticks have been implicated as a competent vector for Borrelia spirochetes (Olsen et al. 1993) and tick-borne viruses (Nuttall 1984), and are thought to impact development, cause anaemia, alter the thermoregulation, and even lead to the death of penguins (Gauthier-Clerc et al. 1998, Mangin et al. 2003). In this report, we note a striking increase in the number of fed ticks found near Adélie penguin rookeries in 2007 compared to 2006, suggesting that the longer and warmer summer of 2007 may have permitted more ticks to find their hosts. High levels of parasitism could be detrimental to the already declining Adélie penguin populations near Palmer Station (Fraser & Patterson 1997).

Deception Island is the largest volcano in the actively extending Bransfield Basin, a marginal basin situated behind the extinct South Shetland Islands arc. Deception Island has been well studied but its submerged flanks have not. A multibeam bathymetry survey was conducted around the island in 2005. Data from the flooded caldera show no evidence for recent localized resurgence. The gently-sloped bottom of the caldera basin is consistent with either a broad zone of resurgence on its east side associated with trap door deformation or with higher rates of sediment supply from the east side of the island. Around the island, numerous tectonic and volcanic features on the volcano's east and west flanks are nearly all aligned with the regional strike (~060°) of the Bransfield rift and there is very little evidence for the other fault populations that have been identified on the island. We infer that models that link the ongoing tectonic development of Deception Island to complex regional tectonics are less likely than models in which the dominant regional extension in Bransfield Strait is modulated by the local effects of caldera collapse and possibly a small right-lateral transfer zone offsetting the primary extension axes in the Central and Western Bransfield Basins.

Except for the rich record from the Neuquen Basin (e.g. Gasparini & Fernández 2006), Jurassic southern Gondwanan marine reptiles are relatively rare. A tooth discovered in the Bean Peaks, Ellsworth Land, Antarctic Peninsula (Fig. 1) represents the southernmost, and only the second record of Jurassic marine reptiles from the Antarctic Peninsula. Comprising a single, incomplete tooth, the specimen is unable to be assigned to a species, but the paucity of Gondwanan Jurassic marine reptile material means this find adds significant palaeobiogeographical information.

We introduce a new bathymetric compilation of the area around South Georgia in the Southern Ocean. Using a variety of data sources including multi and single-beam swath bathymetry we have constructed a gridded bathymetric dataset of the shelf and near-shelf sea-floor areas. The grid has been constructed using a layered hierarchy dependent upon accuracy of each dataset. The spikes and errors have been checked both manually and with a novel semi-automated process. We discuss the resulting bathymetry and the potential uses of the new dataset.