Sources of Antarctic hydrocarbons

By comparing the hydrocarbons of benthic invertebrates from two Antarctic sites, Clarke & Law (1981) concluded that for one of their locations the source was local. In doing so, they questioned our suggestion that a world-wide dissemination of pyrolysis products was partly responsible (Platt & Mackie, 1979). However, we argue here that in fact their results confirm our contention. We also present some new data on the aromatic hydrocarbons of a South Georgia starfish.     

Antarctic tourism and environmental concerns

Increasing numbers of tourists are visiting the Antarctic. Totals from the past three seasons (1989–1990, 1990–1991, 1991–1992) were 2581, 4842, and 6495 respectively (Enzenbacher, 1992). Some environmental issues arising from Antarctic tourist activity include: wildlife tolerance, waste disposal, passenger education, tour operator management practices, personnel experience, frequency of visits and ship design. Current guidelines provide a practical approach to tourism, but do not address all issues arising from tourist activity. Antarctic Treaty Parties agreed to examine the question of a comprehensive regulation of tourist activities in the Antarctic Treaty Area and policies are under review. Some issues may prove difficult to resolve. Compliance with existing guidelines is to be encouraged, at least until more is known about the environmental effects of tourism. A management plan for tourism is needed along with more research on how tourism is conducted and the effects visits have on Antarctica's marine and terrestrial ecosystems. Cooperation between Treaty Parties and tour operators is important for the development of appropriate tourism regulations.     

Al survey of Antarctic meteorites

An²⁶Al survey by non-destructive gamma ray spectrometry was conducted as part of the preliminary examination effort for Antarctic meteorites. A total of 220 samples were studied. The majority of the samples were from the Allan Hills area; however, samples from several other sites, including the Yamato Mountains, were studied. Compared to worldwide falls and finds, the Antarctic group shows a clear trend toward lower²⁶Al levels. At leasr 10% of the samples studied were clearly undersaturated in²⁶Al. The frequency of undersaturated samples suggests that terrestrial ages of several hundred thousand years are common among the Antarctic meteorite collection. The absence of samples with extremely low²⁶Al implies that the upper limit for terrestrial ages in the Antarctic is on the order of 1 million years.     

20th Soviet Antarctic expedition

The toxic effects of crude oil, the dispersant, Corexit 7664, and mixtures of these on the respiration and mortality of two species of bivalve have been examined. A light Arabian crude is most toxic to one, Corexit is most toxic to the other. The susceptibility to oil of the mussel Brachidontes is also reflected in a significant depression of respiration rate at sub-lethal concentrations.     

Metal dynamics in an Antarctic food chain

The concentrations of copper, zinc, cadmium, selenium and mercury were determined in eggs, muscle, liver, kidney and stomach content of nestilings and adults of the Antarctic petrel, Thalassoica antarctica, and its predator, the south polar skua, Chataracta maccormicki, from Svarthamaren, Dronning Maud Land, Antarctica. The dominant food of the petrels is krill, Euphausia superba. The results show relatively high levels of cadmium in krill, which is assumed to be the main reason for the high levels of cadmium in petrels and skuas. Cadmium is almost absent in eggs, but accumulates very rapidly with age in nestlings. The copper concentrations in livers of nestling petrels reach very high levels during growth. This may be seen in connection with physiological development processes. Mercury seems to be accumulated with age and between trophic levels. Among the nestlings, the mercury levels decrease with increasing age, which may be accomplished by the excretion of mercury through the growth of feathers and as a dilution effect during growth. Selenium and mercury are inversely correlated in nestlings. The levels of zinc were similar for different nestling stages and between nestlings and adults in skuas and petrels.     

TBT contamination identified in Antarctic marine sediments

We report for the first time butyltin contamination of near-shore sediments at six sites in the Ross Sea, Antarctica. A very high concentration of 2290 microg Sn kg(-1) sediment was recorded in one sample. The most likely source is abrasion of antifouling paint from the hulls of ice-breakers, but this pattern of contamination is also possible following ship groundings. Antifoulant biocides, such as TBT, have not been considered or detected in Antarctica previously and represent a new challenge to environmental managers and custodians.     

First geomagnetic measurements in the Antarctic region

Based on data from literature and archival sources, we have further processed and analyzed the results of geomagnetic measurements made during the 1772–1775 Second World Expedition by James Cook and the 1819–1821 overseas Antarctic Expedition by Russian mariners Bellingshausen and Lazarev. Comparison with the GUFM historical model showed that there are systematic differences in the spatial structure of both the declination and its secular variation. The results obtained can serve as a basis for the construction of regional models of the geomagnetic field for the Antarctic region.     

Measurements of 36Cl in Antarctic meteorites and Antarctic ice using a Van de Graaff accelerator

Cosmic-ray produced ³⁶Cl(t_1/2 = 3.0 × 10⁵ years) has been measured in four Antarctic meteorites and one sample of Antarctic ice using a tandem Van de Graaff accelerator as an ultrasensitive mass spectrometer with the extremely low background level of ³⁶Cl/Cl< 2 × 10^?16. Results from this ion counting technique (applied here to extraterrestrial materals for the first time) are used to support a two-stage irradiation model for the Yamato-7301 and Allan Hills-76008 meteorites and to show a long terrestrial age (0.7 ± 0.1 m.y.) for Allan Hills-77002. Yamato-7304 has a terrestrial age of less than 0.1 m.y. The ³⁶Cl content of the Antarctic ice sample from the Yamato Mountain area implies that the age of the ice cap at this site is less than one ³⁶Cl half-life.