As Antarctic Science enters its fifth year, it is time to assess progress and review the opportunities for Antarctic research in the coming years. The journal appears to have filled a useful niche, established arange of regular (and irregular!) contributors, and is taken by the majority of major polar libraries world-wide. Quality of production has improved with new equipment but rate of publication has fallen with increasing numbers of acceptable contributions. Cross-disciplinary papers have been few — but perhaps that is because few Antarctic scientists have undertaken the challenge of cross-disciplinary studies? Glaciology and most aspects of atmospheric sciences are still under-represented.

Our first special issue on the palynology of James Ross Island has been well received and a second, on a Southern Ocean cephalopod symposium, is planned for 1994. These special issues are a bonus to subcribers who get the extra pages free. The editors are keen to receive proposals for other special issues with offers of appropriate funding.

Concentrations of mercury were measured in soil and two species of epilithic macrolichens (Umbilicaria decussata and Usnea antarctica) collected along of the coast of northern Victoria Land coast. Most of the soil samples had a very low mercury content, whereas lichens had levels higher than in other remote areas. Although a possible contamination of samples cannot be completely excluded, the relevance to bioaccumulation of the very slow growth rate of lichens and of volcanic activity are discussed.

Diving behaviour of chinstrap penguins (Pygoscelis antarctica) was studied in four adults brooding chicks on Seal Island, South Shetland Islands, Antarctica. During foraging trips to sea, chinstrap penguins made shallow, short duration dives almost continuously, for the most part within 50 m of the surface. Diving effort was concentrated during the daylight hours (10h00-15h00), although a second peak in effort was seen around midnight (22h00-02h00). These peaks were possibly due to the constraints of visual location of prey, chick provisioning, or the need to take advantage of diurnal changes in krill swarm densities or behaviour. It was estimated that most effort was concentrated 3-20 km from shore. Dive depth and duration averaged 31.0 m (± 26.3m) and 72s(± 36s), respectively. Maximum dive depth and duration were 121m and 180s, respectively.

A census of the breeding population of Antarctic fur seals (Arctocephalus gazella) at South Georgia was carried out during the 1990/91 breeding season. Using counts of adult females ashore at the breeding grounds during the pupping period, together with corrections for the likelihood of a female being ashore at a census and for pregnancy rate (71% in 1990/91), pup production was estimated as 269 000 (95% confidence intervals 188 000-350000). The breeding population in 1990/91 was reduced at long-term study sites probably because of limited food availability. Data from these sites were used to estimate the pup production of the population had 1990/91 been a typical year. Based on values from 1983/84 to 1990/91, pup production in 1990/91 would have been 378000 (se=19100) if it had been an average year. The annual increase in pup production from 1976/77 to 1990/91 has declined to 9.8% since the initial period of population expansion in the 1950s and 1960s. Increased population size has led to an expansion of the breeding range at South Georgia.

During January-March, 1991, the distribution and floristic composition of the phytoplankton around Elephant Island, Clarence Island and the northern end of King George Island were determined in relation to physical oceanographic conditions and to proximity of the shelf-break and continental slope. The study area included 180 stations, and c. 5400 km of transects providing continuous measurements of salinity, temperature, beam attenuation, and chlorophyll a (chl a) concentrations in surface waters. The richest phytoplankton areas (2-4 μg chl a 1-1) were generally found associated with a strong salinity front, extending north of King George Island to north of Elephant and Clarence Islands. Data on the phytoplankton community suggest that shelf waters were charaterized by low biomass and a nanoplankton population, while in and just north of the front the biomass increased and there was a shift to a diatom-dominated microplankton population. This is thought to be related to increased stability of the water column just north of the front. The salinity front ran more or less parallel to the continental shelf-break, but its exact position varied during the period of study. It was generally associated with transition water (Type II) or with Weddell-Scotia Confluence water (Type III).

New cytogenetical data are provided for the three Ranunculus species occurring on Iles Kerguelen. Chromosome morphometrical analysis (idiograms) strongly argues for a relationship between them, with some indications of a more recent origin for R. moseleyi. Aneuploidy was found within the three species for the first time. Whilst only a slight aneuploidy exists in R. pseudotrullifolius and R. moseleyi, R. biternatus shows a tendency to hyperaneuploidy. Vegetative reproduction is likely to increase the number of plants showing such chromosome number irregularities. Aneuploidy could explain some of the differences between the species in ecological tolerance and distributional area.

Twelve saline lakes 5-35m above sea level in Bunger Hills (66°10'S, 101°00'E) were investigated from January to April in 1987-89. Some lakes may be relict and all were subject to wind-borne marine salts with present salinities between 3.4-79.0°/‰ and δ18O values mostly between -10 to -14%. Temperatures up to 17.7°C were measured at the bottom of Lake Polest where a sharp thermohalocline was observed during the period of open water. Mg2+ dominated over Ca2+ in all the lakes. Phosphates concentration was 3-10 μgP I-1 and total phosphorus 8-16 μgP I-1. The concentrations of nitrates and nitrites were often equal, ranging between 1-4 μgN I-1. Dissolved O2 was usually near saturation levels but peaked at more than 230% of saturation in the hypolimnion of Lake Polest as a result of temperature-enhanced photosynthesis with an assimilation rate of 23.9 mgC (mg Chl a)-1h-1. The values for chlorophyll a were 0.26-1.93 mg m-3 and for primary production 0.013-0.171 gCm-3d-1, the latter being an order of magnitude higher than in the fresh water lakes of the Bunger Hills.

The various life history stages of the Weddell Sea population of Pleuragramma antarcticum were sampled to investigate life-history patterns of this ecologically important polar fish. Otoliths were examined for size, morphology and microstructure. Age determination of Antarctic fishes has proved to be difficult because of small ambient temperature fluctuations. External and internal examination of otoliths by scanning electron microscopy revealed internal increments (assumed to be daily) and hatching marks. Back calculation of hatching dates from otolith increments, suggested a hatching season from September-November, with recruitment to the adult population at three to five years of age. Growth data conformed well to the von Bertalanffy equation. Fish grew slowly, with the largest fish attaining ages of more than 30 years. A multivariate mathematical model relating age to otolith morphometrics and fish size proved reliable, making it possible to age large sample sizes of fish. Limited elemental microprobe data obtained from two otoliths demonstrated patterns which may be useful in indicating the environmental life history of individual fish. These collective data suggest that the ecological importance of populations of Pleuragramma antarcticum is most likely due to a long life span and high lifetime reproduction rate.

The internal structure of ice cores from western Ross Sea pack ice floes showed considerable diversity. Snow-ice formation made a small, but significant contribution to ice growth. Frazil ice was common and its growth clearly occurred during both the pancake cycle and deformation events. Congelation ice was also common, in both its crystallographically aligned and non-aligned varieties. Platelet ice was found in only one core next to the Drygalski Ice Tongue, an observation adding to the increasing evidence that this unusual ice type occurs primarily in coastal pack ice near ice tongues and ice shelves. The diverse internal structure of the floes indicates that sea ice development in the Ross Sea is as complex as that in the Weddell Sea and more complex than in the Arctic. The mean ice thickness at the ice core sites varied between 0.71 m and 1.52 m. The thinnest ice generally occurred in the outer pack ice zone. Regardless of latitude, the ice thickness data are further evidence that Antarctic sea ice is thinner than Arctic sea ice.

Terrestrial sedimentary rocks at Hope Bay, northern Graham Land are well known for their diverse but poorly-preserved fossil flora, previously assigned ages ranging from Early Jurassic-Early Cretaceous. The beds form part of the Botany Bay Group, which comprises several outcrops of terrestrial sediments in northern Graham Land and the South Orkney Islands. A latest Jurassic or earliest Cretaceous age for the Hope Bay plant bearing sequence (and by extension for the rest of the Botany Bay Group) has been adopted in most recent publications dealing with Mesozoic volcanic arc evolution and palaeogeography of the northern Antarctic Peninsula region. New evidence, based upon the study of extensive collections of previously undescribed fossil plants from Hope Bay and nearby Botany Bay, indicates that they should be assigned an Early Jurassic age. The new palaeobotanical findings, combined with recently-published radiometric data from overlying volcanic sequences, show that a Cretaceous age is no longer tenable for these floras nor, therefore, for the Botany Bay Group in Graham Land. Interpretations of Mesozoic volcanic arc evolution and palaeogeography in this region are revised accordingly.

The Bunger Hills area of the East Antarctic Shield consists of granulite-facies felsic orthogneiss, with subordinate paragneiss and mafic granulite. The igneous precursors of granodioritic orthogneiss were emplaced 1500-1700 Ma ago, and late Archaean (2640 Ma) tonalitic orthogneiss occurs in the nearby Obruchev Hills. Peak metamorphism (M1) (at about 750-800°C and 5-6kb) occurred 1190 ±15 Ma ago (U-Pb zircon age), and was accompanied by the first of three ductile deformations (D1). Emplacement of voluminous, mainly mantle-derived plutonic rocks, ranging from gabbro, through quartz monzogabbro and quartz monzodiorite, to granite, followed between 1170 (during D3) and 1150 Ma. Intrusion of abundant dolerite dykes of four chemically distinct suites at about 1140 Ma was associated with shear zone formation, indicating at least limited uplift; all subsequent deformation was of brittle-ductile type. Alkaline mafic dykes were emplaced 500 Ma ago. Marked geochronological similarities with the Albany Mobile Belt of Western Australia suggest that high-grade metamorphism occurred during collision between the Archaean Yilgarn Craton of Australia and the East Antarctic Shield about 1200 Ma ago.

Geologists from many countries have worked in Antarctica since the turn of the twentieth century and during the past thirty years the level of research activity on the continent has increased annually. As a result there has been a proliferation of stratigraphical names and lithostratigraphical schemes (Thomson, 1990). Furthermore, geologists from different nations are familiar with different standards and codes of nomenclature, which has resulted in a number of inconsistencies in Antarctic stratigraphical names. The SCAR Working Groups on Geology and Solid Earth Geophysics therefore recommended at their meeting in 1990 with SCAR XXII in São Paulo that, for sedimentary rocks, geologists working in Antarctica should adhere to the stratigraphical principles and recommendations proposed by Hedberg (1976). It was recognized, however, that igneous and metamorphic rocks present special problems of nomenclature. An ad hoc group of the SCAR Working Group on Geology for naming igneous and metamorphic rock units, constituted by the authors of this note, was therefore established to consider and discuss these problems and to formulate recommendations for suitable schemes that may be used internationally for Antarctica.

Because of its remoteness, Marie Byrd Land is among the most inaccessible and least visited parts of Antarctica. However, it contains a very poorly studied, large Cenozoic alkaline volcanic province and an outstanding record of volcanism coeval with glaciation (LeMasurier & Thomson 1990). This short note describes the results of the second of two planned periods of fieldwork, which form part of the West Antarctic Volcano Exploration (WAVE) project. The background to WAVE and preliminary results of the 1989–1990 fieldwork are described in Smellie et al. (1990) and McIntosh et al. (1990). The studies described here took place between 2 November 1990 and 11 January 1991.

The paper discusses ELF-VLF investigations of the low Antarctic ionosphere. Two new methods of lower ionospheric diagnostics are based on an investigation of the VLF electromagnetic field structure in the Earth-ionosphere cavity. One method deals with the analysis of local transverse cavity resonances in the near field of an emitter (a horizontal antenna) with a frequency (~1.5-8 kHz) in the range of the first few resonances. The other method, based on tweek investigations, is applicable under night conditions and enables the characteristics of the low ionosphere to be determined over a signal propagation path. The use of the ELF-VLF transmitter at Siple Station provides a unique opportunity to implement these methods, as does the ELF multipoint recording in the Schumann resonance band of atmospherics excited by powerful lightning discharges.