There are increasing commercial pressures to send more people to the Antarctic. Visitor numbers each summer now exceed scientist numbers on the continent. The commercial operators working through IAATO have, to date, been largely acting in an environmentally responsible manner, realising that there is no point killing the goose with the golden egg. In fact, it has been argued that visitors to the Antarctic, many of whom are wealthy or influential, have played a significant role in increasing environmental awareness of the continent and its wildlife to politicians and to the public.

Temporal and spatial variations of the hydrogen peroxide accumulation were measured in off-shore waters and in intertidal rockpools near Jubany Station, King George Island, South Shetland Islands. As H2O2 photoformation is mainly driven by the short wavelength radiation in the UV-B and the UV-A range of the solar spectrum, the study was conducted between the beginning of October and the end of December 1995, the period of Antarctic spring ozone depletion. Wet deposition of H2O2 containing snow was identified as a major source of hydrogen peroxide in the surface waters of Potter Cove. As the concentrations of dissolved organic carbon (DOC) in Potter Cove surface waters were low (121 ± 59 μmol Cl−1), when compared to the highly eutrophicated waters on the German Wadden coast (6000–7000 μmol Cl−1), direct UV-induced DOC photo-oxidation was of only limited significance in the Antarctic sampling site. Nonetheless, under experimental conditions, H2O2 photoformation in Potter Cove surface waters amounted to 90 ± 40 nmol H2O2 h−1 l−1 under a UV-transparent quartz plate. When high energy UV-B photons were cut-off by a WG320 filter formation continued at a rate of 66 ± 29 nmol H2O2 h−1 l−1 due to UV-A and visible light photons. Samples from freshly deposited snow contained between 10 000 and 13 600 nmol H2O2 l−1, and a snowfall event in mid November resulted in a maximum concentration of 1450 nmol H2O2 l−1 in the upper 10 cm layer of Potter Cove surface waters. Maximal H2O2 concentrations in intertidal rockpools were even higher and reached up to 2000 nmol H2O2 l−1 after the snowfall event. During a grid survey on December 17 1995, H2O2 concentrations and salinity displayed a north to south gradient, with higher concentrations and PSU at the south coast of the cove. The reasons for this spatial inhomogenety are as yet unknown, but may relate to a minor local input of photo-reactive organic matter from creeks entering the cove in the south-east, as well as to waste water discharge from the station, located on the south beach.

Champsocephalus esox is the only icefish species found outside Antarctica. In a population from the Beagle Channel, the complete annual reproductive cycle has been determined. Gonad maturity stages have been established for males and females by histological analysis. Males are sexually mature from January–September with a maximum gonadosomatic index (GSI) of 3.63%. Histologically, testes are very homogeneous and the degree of maturation of the testicular cysts is similar among different tubules at the same maturation stage. Running ripe testes have mature sperm and a few spermatogoniae arranged near the blind end of the tubules. In sexually active females that are found from February–November, ovaries contain only ripe oocytes or postovulatory follicles, together with a batch of previtellogenic oocytes. During hydration, oocyte diameter reaches 2.7 mm, and oocyte dry weight increases due to material intake, the maximum GSI in ovulated ovaries is 21.89 and hepatosomatic index (HSI) decreases. These facts suggest a transfer of matter from liver to the gonads. Absolute fecundity ranges from 3303–8600 oocytes. Relative fecundity ranges from 22.5–43.5 oocytes per gram total weight. In C. esox, relative fecundity has a similar range to those quoted for the different C. gunnari populations, whilst mature oocyte diameter is small and reproductive season extended compared to the same parameters in other Channichthyidae.

Records (by a scientific observer on a longline fishing vessel around the Falkland Islands) of 86 different individually colour-banded wandering albatrosses from South Georgia, provide new insights into the use of the waters of the Patagonian shelf slope by birds from breeding grounds some 600 km to the south-east across the Antarctic Polar Front. Birds recorded were aged from 3–39 years, almost the full range (except 1 and 2 year olds) of South Georgia colour-banded birds, about 5% of whose colour-banded population was observed during the study. Immature birds (up to age 7 years) formed only 9% of the total; this may reflect relative absence from the area but might also relate to their subordinate status to adults at fishing vessels. Most birds seen were current breeders at South Georgia, including both sexes in the month prior to arrival on the breeding grounds (October), females during the pre-laying exodus (December) and both sexes during incubation (January) and throughout the main chick-rearing period (May, June, October). Only birds which had already failed were seen in the brooding period (March–April), when foraging trips are too short to reach the Falklands. Females outnumbered males in all these categories, supporting suggestions of different distributions of the sexes at sea during breeding. Birds of both sexes that had bred at South Georgia in the previous year were seen mainly between January and April. Birds that had not bred for at least three years were mainly males and mainly seen in January. These data indicate the importance of the waters near the Patagonian Shelf, especially around the Falklands, for wandering albatrosses from South Georgia, particularly breeding birds but also birds in their year(s) between breeding attempts. This is of particular relevance, given the globally threatened status of the species and the possibility of hydrocarbon exploitation in waters around the Falklands.

The elemental and biochemical composition of eight moss species from the maritime Antarctic were determined fornightly (summer) or monthly (winter) from December 1992 to November 1994. Short-duration summer carbohydrate maxima in Calliergon sarmentosum were seen in both years, but no other seasonal patterns were observed. The absence of seasonality in carbon, nitrogen and phosphorus concentrations or their atomic ratios suggest that the mosses were nutrient-sufficient throughout the year, and that nutrient availability was not important in determining moss productivity. Mosses from hydric habitats had lower carbohydrate and higher protein, nitrogen and phosphorus contents than those from drier habitats, possibly as a consequence of higher productivity and continual flushing with nutrients in wet habitats. The results are consistent with the importance of water and the primacy of physical factors in the ecology of Antarctic mosses.

In order to infer the origin and the evolution of Antarctic Collembola, a correct phylogenetic analysis depicting relationships among Antarctic and non-Antarctic species is required. A preliminary assessment of the value of DNA sequences in reconstructing phylogenetic relationships among the Antarctic Isotoma klovstadi and other non-Antarctic species was carried out by sequencing one mitochondrial gene (Cytochrome c oxidase, subunit II) and two nuclear genes (a fragment of the 28S rDNA and the Elongation Factor-1α). Estimates of base composition heterogeneity revealed that in the two protein-coding genes (COII and EF-1α) 3rd codon position sites are compositionally very heterogeneous and the analysis of these two genes was therefore performed only on 1st and 2nd codon position sites. Phylogenetic analyses using Maximum Likelihood, Maximum Parsimony and Minimum Evolution revealed that the COII and the EF-1α genes are more suitable than the D3 fragment for the reconstruction of phylogenetic relationships within the Family Isotomidae to which Isotoma and several other genera of Antarctic Collembola belong.

Thirty-four permanently stratified water bodies were identified in a survey of the Vestfold Hills. Of these, 21 were lakes, six were seasonally isolated marine basins (SIMBs), and seven were marine basins with year round connection to the open ocean. The basins varied markedly in salinity (4 g l−1 to 235 g l−1), temperature (−14°C to 24°C), depth (5 m to 110 m), area (3.6 ha to 146 ha) and surface level (−30 m to 29 m above sea level). The stratification in all the basins was maintained by increases in salinity. During winter, a thermohaline convection cell was present in all lakes and SIMBs directly beneath the ice cover. These cells were the result of brine exclusion from the forming ice, and increased in density throughout winter, penetrating progressively deeper into the lake. Minimum stability, and therefore the maximum likelihood of turnover, occurred at the time of maximum ice formation in spring. At the end of the period of ice formation, the convection cell broke down, and stratification of the surface water occurred. When the ice melted completely, lenses of relatively fresh water capped the lakes, which reduced the effect of wind mixing. Net meltwater input increased the stability of the meromictic basins, while periods of lower water level resulted in deeper penetration of the thermohaline convection cell, increasing the possibility of turnover and destratification.

The elephant seal populations breeding on the Îles Crozet and Kerguelen were regularly surveyed over the last three decades. At Îles Kerguelen the number of breeding females decreased at an annual rate of 3.6% between 1970 and 1987, then increased at an annual rate of 1.1% to 1997. At Îles Crozet, the population was reported to decrease at a rate of 5.35% between 1970 and 1990 but no change in numbers was found between 1990 and 1997. These results indicate that the rapid decline observed both at Îles Crozet and Îles Kerguelen has ended, and these populations are now either stable or slightly increasing. We suggest that broad scale change in environmental factors affecting the food availability for elephant seals may be responsible for the change in numbers of these marine predators. The higher rate of decrease, the longer period of decline, and the absence of any significant change between 1990 and 1997 observed on the Îles Crozet may be explained by additional factors such as killer whale predation.

Environmental conditions, both external to and within three shallow ponds of the McMurdo Ice Shelf, were measured over an annual cycle between January 1997 and January 1998. We combined this with a study of the response of the benthic microbial mat communities to the transition from summer conditions to winter freezing. Over the study period air temperature was above 0°C for a few days during summer. At this time pond temperatures were higher than air temperatures, with evidence of thermo-haline stratification. The shallow areas of ponds froze between late February and early March, with bottom waters in the deepest pond remaining unfrozen until early June. Minimum winter air temperatures were below −40°C. There was little evidence of freezing point depression due to freeze-concentration of solutes, except at the very bottom of ponds. In the most conductive pond investigated, the temperature of basal freezing was −4°C and conductivity did not exceed approximately 60 mS cm−1 immediately prior to freezing. Microbial mats remained photosynthetically active up to conductivities between 40 and 80 mS cm−1, and were able to acclimate to lowered irradiance associated with ice formation. Although photosynthesis and respiration were reduced by 11% and 40% respectively at temperatures of −2°C compared to 1°C, there was no difference in light harvesting efficiency. Results from this study suggest that light limitation of photosynthesis, or freezing, determine the growth season for the microbial communities, depending on depth.

Magnetic anomaly mapping is used to interpret crustal structure and tectonic evolution of Victoria Land and of the adjacent Ross Sea. Previous interpretation of magnetic anomalies verified seismic and gravimetric findings in the Ross Sea by placing additional constraints both on crustal structure and magmatism of the West Antarctic rift system. An aeromagnetic map of the central-southern part of Victoria Land produced in the framework of the GITARA project, provides new crustal images of part of the Transantarctic Mountains rift shoulder. The map was interpreted to study the transition between the Wilson Terrane and the Precambrian East Antarctic Craton, the extent and distribution of Jurassic tholeiitic magmatism, and the occurrence of post- Jurassic faulting oblique to the rift basins. A compilation with adjacent aeromagnetic data was recently used to study the structures inherited from the Palaeozoic terranes and their reactivation as major fault zones separating different crustal blocks along the TAM rift shoulder. Additional aeromagnetic coverage over a 35 500 km2 sector of northern Victoria Land was acquired during the GITARA 5 (1996/97) survey. The flight altitude was 9000 ft and profile line spacing was 4.4 km for the regional grid and 2.2 km for the detailed one, with a tie line interval of 22 km. Standard processing techniques, optimized with microlevelling procedures were applied to the data to produce a 1:250 000 magnetic anomaly map. The processed GITARA 5 magnetic dataset is a new tool to study the structure of the Rennick Graben, and its relationship to the Palaeozoic Wilson Terrane-Bowers Terrane and Robertson Bay Terrane suture zone. The new map also represents important progress towards a magnetic anomaly compilation over the whole of Victoria Land, since it links previous efforts near the Pacific Coast with those near the Ross Sea.

Highly deformed metaconglomerates, mafic to felsic in composition, characterize the eastern Lanterman Range (northern Victoria Land, Antarctica). In the literature the mafic and felsic metaconglomerates are known as Husky Conglomerate and Lanterman Conglomerate respectively. They occur in a 25 km long strip along the Lanterman Fault, which is a major tectonic boundary between the Wilson and the Bowers terranes. New field observations show that there is a gradual transition from mafic to felsic metaconglomerates: this supports a stratigraphical continuum from Husky to Lanterman Conglomerate, and indicates that they belong to the same sedimentary succession. Structural analysis indicates that Husky and Lanterman conglomerates suffered the same structural evolution. From all these evidences, there is no reason to distinguish two types of metaconglomerates, apart from the diversity in the lithological features. However the two terms “Husky Conglomerate” and “Lanterman Conglomerate” can be still used to refer to the mafic and felsic facies of the same sedimentary succession. On the basis of their lithology the Husky Conglomerate can be derived from the Glasgow volcanic arc, whereas the felsic clasts of the Lanterman Conglomerate may be derived from a continental basement below the Glasgow arc or from a continental block bounding the Bowers trough.

Much of Antarctica's Devonian to Jurassic geological history is interpreted from the study of the Beacon Supergroup in the central Transantarctic Mountains. The upper part of the succession has been extensively investigated, although, few studies focus on the basal rocks. Deposition occurred within a Transantarctic basin believed to have extended along the edge of the East Antarctic Craton in early Beacon time, either as a marginal, passive margin, or a cratonic basin. Early basinal deposits include the Devonian Taylor Group and Upper Carboniferous–Lower Permian glacial sediments. Previous studies concluded that the Taylor Group in CTM was deposited as a continuous sheet across the low-relief Kukri Erosion Surface that developed on the planed Ross orogenic belt. These interpretations also concluded that late Palaeozoic glaciation truncated the Devonian sheet. New data suggest that this view, and current models for the early Beacon basin, maybe incorrect. Lithofacies, palaeocurrent orientations, sandstone composition, and stratigraphical relationships of central Transantarctic Mountains rocks suggest that deposition occurred within two intermontane or successor basins following post-orogenic uplift of the Ross terrain. Segregation of lithofacies and onlap of Taylor Group rocks onto an undulating Kukri Erosion Surface show that a basement high separated non-marine deposits between the Byrd and Ramsey glaciers from marine sediment in the Ohio Range. Onlap of glacial rocks and palaeocurrent data suggest intermontane conditions continued until the Early Permian.

Gravity cores taken from five sites in the Nielsen basin, a sinuous trough on the Mac. Robertson shelf of the East Antarctic continental margin, have yielded non-marine palynofloras of late Early Jurassic to Early Cretaceous age. The palynomorphs occur in glacimarine muds and are thus not in situ, but the composition of the samples indicates that no mixing of individual assemblages has occurred, and that the sediments were deposited very close to outcrop of the source of the palynomorphs. The sequence is oldest at the seaward end of the Nielsen basin, and youngest near the fault-bounded landward end. It is interpreted as reflecting pre-break-up deposition on a passive, rifted continental margin. The age of the assemblages has been established by comparison with the zonal scheme developed in the Perth Basin of Western Australia. Similarity of the Antarctic palynofloras with those known from basins on the east coast of India confirms continental reconstructions that show this part of East Antarctica to have been contiguous with eastern India prior to break-up. The non-marine character of the palynomorphs suggests that marine conditions in this region of the Antarctic margin did not develop until at least late Early Cretaceous time.

Large glacial boulders, up to several metres in diameter, resting on the lake ice are a remarkable feature of Lake Untersee (71°21'S, 13°28'E), an ice-dammed, perennially frozen freshwater lake in the Ottovon-Gruber-Gebirge (Gruber Mountains) of central Queen Maud Land, East Antarctica. A geodetic survey of such ice-rafted boulders was made over two summer seasons to determine the direction and velocity of their movement. They are transported between 3.9 and 11.1 m annually and the residence time of the boulders is estimated at approximately 500 years. Lake Untersee must have been permanently covered with lake ice for at least that long.

CCl3F (or CFC-11) and CCl2F2 (or CFC-12) were determined in air samples collected, during subsequent summer Antarctic campaigns, in different sampling sites in the Ross Sea Region. The samples were analysed by GC-ECD after enrichment. Data obtained since 1988–89 were plotted to observe the trend of CFCs atmospheric concentration levels. A decrease in the rate of increase of CFC-12 concentration was observed, whilst the concentration of CFC-11 was actually seen to be decreasing.