Anniversaries punctuate all our lives, providing the semicolons that cause us to pause and think again. Everyone has plenty of personal anniversaries but there are also cultural and institutional ones that we can use as an opportunity to remember but also as a platform to leap forward. How far have we come and where do we want to be in the future? The recent announcement of an International Polar Year (IPY) in 2007 is linked to the fiftieth anniversary of the International Geophysical Year, an event that proved to have such momentous consequences both for Antarctic science and for international politics.

The syntypes of the endemic Southern Ocean octopodid Pareledone polymorpha (Robson, 1930) were re-examined and measurements, counts and indices are presented. The two forms described by Robson, namely oblonga and affinis, are determined to have no taxonomic validity. The species polymorpha shows morphological similarities with Pareledone adelieana (Berry, 1917) but differs in relative arm lengths, sucker counts, external colouration and size at maturity. Both species are transferred to the new genus Adelieledone, which is separated from the genus Pareledone s.s. by the transverse ridges in the ligula groove of the hectocotylus, the sharp tip of the lower beak, the enlarged posterior salivary glands, the absence of stylets and by skin sculpture, especially by the presence of two longitudinal integumentary ridges on the dorsal mantle. A new species, Adelieledone piatkowski, is described from the Antarctic Peninsula. Beak morphology can discriminate the genera in predator studies.

The biogeochemical cycle of lead in the marine coastal environment of Terra Nova Bay has been investigated by determining the lead concentration in a large number of matrices: marine sediments, pack ice, snow, seawater, marine microlayer, aerosol and eight species of marine organisms (the bivalve molluscs Adamussium colbecki and Laternula elliptica, the seastar Odontaster validus, the sea urchin Sterechinus neumayeri, the fish Trematomus bernacchii, the seaweeds Iridaea cordata and Phyllophora antarctica, and the nemertine worm Parborlasia corrugatus). The study of solid speciation of sediment showed that the site is not influenced by human activity and is hence suitable to examine natural processes. The concentration values found in the suspended paniculate matter (SPM) of pack ice core, aerosol, marine microlayer and seawater as well as the particulate morphology, investigated by SEM, seem to support the hypothesis that particulate lead is transferred from the atmosphere to the water column through three different mechanisms: (i) release of SPM from the pack ice during its melting, (ii) input from the continental land through wet deposition, (iii) transport by aerosol and marine microlayer. Concentration data both in the whole organism and in some target organs indicated two suitable biomonitor organisms: the bivalva Laternula elliptica (particularly its digestive gland) and the fish Trematomus bernacchii (particularly its bones).

The composition of suprabenthic Peracarida from a depth between 1 and 1.33 m above the seafloor was investigated. In order to study the abundance and diversity quantitatively, the samples were taken by means of the supranet of an epibenthic sledge off Kapp Norvegia and off the South Shetland Islands. The samples were taken during ANT XVII-3 with RV Polarstern in April and May 2000. These samples of EASIZ III received during the Antarctic autumn are compared with those of EASIZ II taken during the summer. While the autumn samples show far less abundance of all peracarid taxa, the diversity is about twice as high as during summer. In total 115 species of peracarid crustaceans were sampled at six stations yielding 1336 individuals standardized to 1000 m3 hauls. Amphipoda clearly dominated in abundance and diversity.

New populations of the two species of calanoid copepods known to inhabit freshwater lakes in East Antarctica, Boeckella poppei (Mrázek, 1901) and Gladioferens antarcticus Bayly, 1994, have recently been discovered. The morphology of the populations of B. poppei showed significant differences, notably a reduction in the armature of the male fifth leg, when compared with typical specimens from the Antarctic Peninsula and South America. Gladioferens antarcticus had previously been recorded from a single lake in the Bunger Hills, but has now been recorded from three further lakes in this region. A recent review of Antarctic terrestrial and limnetic zooplankton suggested that neither of these species can be considered an East Antarctic endemic, with B. poppei being listed as a recent anthropogenic introduction and G. antarcticus a ‘marine interloper’. We conclude differently: B. poppei has been present in isolated populations in East Antarctica for significant lengths of time, possibly predating the current interglacial, while G. antarcticus is a true Antarctic endemic species whose ancestors have been present in the region since before Australia separated from Antarctica.

The phenology of six Antarctic red macroalgae, Delesseria salicifolia Reinsch, Gymnogongrus antarcticus Skottsberg, Gymnogongrus turquetii Hariot, Hymenocladiopsis crustigena Moe, Kallymenia antarctica Hariot and Phyllophora ahnfeltioides Skottsberg, was investigated in a two-year culture study under fluctuating daylengths imitating the conditions of King George Island, South Shetland Islands. The algae were cultured at 0°C in filtered, nutrient enriched seawater under photon fluence rates of 3, 10, 25, 50 μmol photons m−2 s−1. All species are classified as season anticipators, starting growth in late winter–spring and stopping growth before the summer solstice. Formation of new blades was observed from January/February onwards in most of the species. Carpospore formation was observed in K. antarctica in early summer. Growth was light saturated at photon fluence rates of 3 μmol photons m−2 s−1 in D. salicifolia and at 10 μmol photons m−2 s−1 in the other species, corresponding to an annual light dose of 31.4 and 157 mol photons m−2. The results show that this type of life strategy is typical for species from the Antarctic and give further evidence on the high degree of shade adaptation of Antarctic algae and predict a lower distribution limit for these species at 37 ± 15 m and 23 ± 10 m, respectively.

An index of integrated food preferences (IFA) of Notothenia coriiceps Richardson at two sites in Admiralty Bay (Ipanema and Smok Point), calculated for two sequential summers, showed that during 1998/99, the most important food item was Euphausia superba (krill) at both Ipanema (IFA = 0.83) and Smok Point (IFA = 0.75), while the sum of all other food items was significantly smaller (IFA respectively 0.21 and 0.26). Macroalgae, gammarid amphipods and gastropods dominated the diet in the summer 1999/00 (IFA respectively 0.32, 0.32 and 0.21), at Ipanema, while macroalgae were dominant at Smok (IFA = 0.67), where krill and amphipods were secondary prey (IFA respectively 0.12 and 0.14) and gastropods were absent. Thus, the diet composition of N. coriiceps can possibly be used as an indicator of the presence of pelagic krill swarms.

Two species of euphausiids (Thysanoessa macrura Sars and Euphausia vallentini Stebbing) from the Southern Indian Ocean were analysed for their lipid content, fatty acid and fatty alcohol composition, in relation to developmental stage (T.m) and sex (E.v). Lipid composition showed wax esters and triacylglycerols as main neutral lipids for T. macrura and E. vallentini respectively. Allometric relationships between lipid class and total lipids indicated that changes in total lipids were size dependent and mainly related to wax esters in T. macrura and polar lipids (both phosphatidylcholine or PC and phosphatidylethanolamine or PE) in E. vallentini. No difference in lipid composition could be shown for male and female E. vallentini, while sampling location, developmental stage and sex were significantly influential in T. macrura. In this latter species wax esters displayed relatively similar fatty acid and alcohol composition in both juvenile and female stages, whereas a striking difference could be seen between females and juveniles in terms of polar lipids with a very low PE content in females. Male and female E. vallentini showed little differences in fatty acid structure with the exception of PC in females, which were low in 22:6n-3. The trophic status of these two species was established using multivariate discriminant analysis, which indicated for E. vallentini a degree of omnivory similar to E. superba, while these T. macrura appeared more omnivorous than individuals collected in other areas of the Southern Ocean. Clustering of polar lipid composition suggested a link between differences in PC fatty acid and the post-spawn stage of the female of E. vallentini collected. The same probably applies for the changes in PE recorded for T. macrura females.

The validity of the Antarctic species of the “Oikopleura gaussica group” (O. gaussica, O. valdiviae, O. drygalskii, and O. weddelli) is discussed. The characteristics of new material from South Georgia and the Bellingshausen Sea are compared with the original descriptions. We examined 495 specimens at different stages of maturity and concluded that the characters used to differentiate these species of Oikopleura have not enough weight to justify their separation. The morphological variations found were ascribed either to intraspecific variability and/or to the different degree of maturity of the specimens examined of a single species, Oikopleura gaussica. The main taxonomic characters for the identification of this species are: the particular way in which the flat triangular gonads surround the intestinal ball like a sheath, the equal size of the two lobes of the stomach, the oesophagus entering the postero-dorsal edge of the rounded left lobe of the stomach, the presence of oval and some times lobate oral glands, and the variable number of subchordal cells (4 to 14) arranged in a single row on the right (ventral) side of the chorda.

Deschampsia antarctica is a freezing-tolerant plant and the only native Poaceae that grows in the Maritime Antarctic. During the long days of the growing season this plant accumulates sucrose (Suc) in the leaves to 36% of the dry weight. The mechanism that leads to this high accumulation is unknown. The effect of day length and low temperature on sucrose phosphate synthase (SPS) (EC: 2.4.1.14) activity and sugar accumulation was studied in D. antarctica and compared with other Poaceae. Three different day lengths: short (SD) (8/16 h), medium (MD) (16/8 h) and long (LD) (21/3 h); and two temperatures: 4°C (cold-acclimated) and 15°C (non-acclimated) were tested. The highest contents in total soluble sugars (TSS) and Suc were reached in crowns and leaves, respectively, in cold-acclimated plants under LD. TSS and Suc contents and SPS activity with cold acclimation were higher in D. antarctica than in other agricultural (wheat, oat and barley) and non-agricultural (D. caespitosa and D. beringensis) Poaceae species. Suc/TSS ratio was higher in all Deschampsia species than in agricultural Poaceae species. SPS activity and sucrose content in leaves were positively correlated only in LD cold acclimated plants. This result shows that SPS activity is responsive to day length in D. antarctica.

The question of how stable the climate in Antarctica has been during the last few million years compared to the rest of the planet is still controversial. This study attempts to add new information to the discussion by reconstructing the timing and spatial extent of glacial advances in northern Victoria Land over tens of thousands to millions of years. In Terra Nova Bay region, surface exposure ages and erosion rates of glacially rounded bedrock and glacial erratics have been determined using the cosmogenic nuclides 3He, 10Be and 21Ne. Three morphological units have been analysed. They yield minimum ages of 11 to 34 ka, 309 ka, and 2.6 Ma, respectively. Erosion rates were as low as 20 cm Ma−1 since middle Pliocene time. Taking erosion into account, the oldest surface is 5.3 Ma old. Pleistocene glacier advances had considerable extent, reaching up to 780 m above modern ice levels, but have been restricted to the valleys since at least mid-Pliocene. The existence of landscapes of mid-Pliocene age in northern Victoria Land implies that the climatic stability of the McMurdo Dry Valleys is not unique within the Transantarctic Mountains, but rather the expression of a constantly cold and hyperarid climate regime in entire Victoria Land.

Semi-continuous, linear accumulations of poorly-sorted debris are present on the surface of the remnant Larsen-A Ice Shelf, Antarctic Peninsula. These accumulations form a complex of debris bands extending parallel to the front of the ice shelf for several kilometres. Landsat imagery shows that the debris bands originated as lateral moraines along the Nordenskjöld Coast. Almost 80% of clasts sampled from these debris accumulations have shape/roundness characteristics consistent with glacier transport in the zone of basal traction. Angular and very angular clasts account for 15% and 22% of clasts in the pebble- and cobble/boulder-sized fractions, respectively, and originated by rockfall from valley/nunatak sides, with subsequent passive glacier transportation. Lithological analysis indicates that the debris is derived locally from the Nordenskjöld Coast, Cape Fairweather region and interior of the Antarctic Peninsula. Episodic melt-out and resedimentation of this debris from the front of the ice shelf would deliver pulses of coarse-grained sediment to the sea floor. Therefore, coarse-grained debris can also be released along the calving margin of small polar ice shelves fringing mountainous terrain, and could potentially be confused with sediment deposited at the grounding line of Antarctic ice-shelves. Sedimentological criteria to differentiate between these environments are proposed in this paper.

A shark tooth from the Spartan Glacier Formation of the Fossil Bluff Group of Alexander Island, Antarctic Peninsula is described and assigned to Palaeospinacidae, an extinct group of neoselachian sharks. This tooth was previously supposed to have been recovered from Middle Jurassic strata and to belong to Hybodus. However, sedimentation of the Spartan Glacier Formation was from the Valangian to Aptian. Consequently, an Early Cretaceous age is assigned to the specimen although its exact stratigraphical horizon is unknown. A generic assignment, however, is not possible although it may belong to Paraorthacodus. This specimen represents the first record of a neoselachian from the Early Cretaceous of Antarctica.

Fossil diatom-bearing marine sediment cores recovered from Prydz Channel, Prydz Bay, record episodes of glacial advance and retreat in the bay. Diatom frustules are abundant, well preserved, and the species composition is diverse in two biogenic sediment units composed of siliceous diatom ooze (SMO-1 and SMO-2). Between SMO-1 and SMO-2 a terrigenous unit (T) is present, composed of muddy diamicton and sandy silty clay, which contains poorly preserved rare diatoms. The SMO units are interpreted to represent an open marine setting with seasonal sea ice cover; the T unit is interpreted to represent glacial ice expansion from the Amery Ice Shelf over the site. Based on an age model developed previously for other cores from Prydz Channel with analogous stratigraphies, we interpret our record to be late Quaternary through Holocene in age. The T unit records the Last Glacial Maximum (LGM) in Prydz Bay; the SMO-1 and SMO-2 units record interstadial episodes that are post- and pre-LGM respectively. Extinct diatom taxa in the T and SMO-2 units indicate reworked sediment sourced from two different-aged deposits. Our results provide both a new interpretation of late Quaternary deposition in Prydz Channel and support for previous studies in this region.

Sedimentary sequences spanning early Oligocene and Neogene time intervals were recovered with piston and gravity cores along erosional structures at northern Gunnerus Ridge and Kainan Maru Seamount in the southernmost Indian Ocean. Results of sedimentological investigations help to reconstruct the Cenozoic palaeoenvironment. Main emphasis was placed on grain size and clay mineral data. The clay mineral assemblages are dominated by illite and smectite. Chlorite and kaolinite occur in trace amounts. Whereas illite has a distinct source on the East Antarctic craton, smectite is of somewhat speculative origin, but probably is derived from erosion of Cenozoic or older shelf sediments. The presence of terrigenous sand indicates that ice-rafting was active throughout the time represented by the investigated cores, although with varying intensity. During the early Oligocene interval (30.1–29.0 Ma), siliceous phytoplankton production dominated sedimentation. Environmental conditions were quite different from those on Maud Rise and Kerguelen Plateau. The middle Miocene sedimentary sequence (14.1–12.8 Ma) documents an intensification of East Antarctic glaciation. The sediments deposited during the late Miocene interval (8.7–6.5 Ma) and the Pliocene interval (5.1–2.7 Ma) indicate continued cooling of Antarctica, but a more dynamic Antarctic ice sheet resulting in episodic sedimentation patterns.

Data from eight CTD casts and two one-year long current time series collected at 8 and 60 m above the seafloor of a sediment drift, off the Pacific Margin of the Antarctic Peninsula are presented, with special emphasis on bottom boundary layer dynamics and processes relevant to sediment settling and re-suspension. The water masses over the drift are characterized, including also a comparison with other measurements available from that region. The south-westward flow along the continental rise exhibits a strong topographic (bathymetric) control in the near-bottom current regime. A consistent mean flow deflection between an upper and lower current regime suggests that only the lower regime falls within a bottom (turbulent) Ekman layer. The bottom current regime is not energetic enough to maintain the coarse sediment fraction in suspension. The absence of evidence for a nepheloid layer justifies the assumption that most sediment was supplied to the margin during glacial periods. Two events, with peak velocities of up to 20 cm s−1, are associated with barotropic eddies shown as negative (cyclonic) mean sea level anomalies detected by ERS/TOPEX satellite altimeters. These energetic bottom current pulses may give way to episodic sediment re-suspensions of the sortable (non-cohesive) part of the sediment, thus exerting a minor role in redistributing fine sediments through the mean flow regime.

Byrd Glacier has one of the largest ice catchment areas in Antarctica, delivers more ice to the Ross Ice Shelf than any other ice stream, and is the fastest of these ice streams. A force balance, combined with a mass balance, demonstrates that stream flow in Byrd Glacier is transitional from sheet flow in East Antarctica to shelf flow in the Ross Ice Shelf. The longitudinal pulling stress, calculated along an ice flowband from the force balance, is linked to variations of ice thickness, to the ratio of the basal water pressure to the ice overburden pressure where Byrd Glacier is grounded, and is reduced by an ice-shelf buttressing stress where Byrd Glacier is floating. Longitudinal tension peaks at pressure-ratio maxima in grounded ice and close to minima in the ratio of the pulling stress to the buttressing stress in floating ice. The longitudinal spacing of these tension peaks is rather uniform and, for grounded ice, the peaks occur at maxima in surface slope that have no clear relation to the bed slope. This implies that the maxima in surface slope constitute a “wave train” that is related to regular variations in ice-bed coupling, not primarily to bed topography. It is unclear whether these surface “waves” are “standing waves” or are migrating either upslope or downslope, possibly causing the grounding line to either retreat or advance. Deciding which is the case will require obtaining bed topography in the map plane, a new map of surface topography, and more sophisticated modeling that includes ice flow linked to subglacial hydrology in the map plane.