bluuebunny/crossref_metadata_2025 huggingface dataset:
Devonian depositional environments in the Darwin Mountains: Marine or non-marine?
Authors: Woolfe Ken J.
Published: December 2007

The depositional environment of the Devonian Taylor Group has been subject to considerable debate for over 30 years. The debate stems largely from a belief that the abundant and diverse trace fossils represent a marine ichnofauna, whereas sedimentary features, including palaeosols, desiccation polygons and red beds, are more typical of a non-marine setting. The debate is reconciled by a reinterpretation of the trace fossil assemblage which shows that the trace fossils comprise a typical fresh water (Scoyenia ichnofacies) assemblage, and their occurrence in the Taylor Group in the Darwin Glacier area is entirely consistent with deposition in a mixed fluvial-lacustrine-subaerial environment.
Estimated food consumption by penguins at the Prince Edward Islands
Authors: Adams N. J. , Moloney C. , Navarro R.
Published: December 2007

The consumption of food by the four species of breeding penguins at the Prince Edward Islands is assessed on an annual and seasonal basis. Total annual food consumption was estimated at 880 000 t, of which king penguins accounted for 74%, macaroni penguins 21%, rockhopper penguins 5% and gentoo penguins <1%. Pelagic fish, almost entirely myctophids, were the most important prey (70% of total prey biomass), followed by pelagic crustaceans (18%) and cephalopods (11%). Demersal fish and benthic crustaceans accounted for <1% of total consumption, being consumed only by gentoo penguins. Peak demands of between 2 and 3.3 × 106 kg d−1 occurred from October–December when three of the four species were breeding, including the two demi-populations of king penguins. Food demand decreased to 1.2 × 106 kg d−1 during winter when only king and gentoo penguins were present. Much of the prey are presumably captured within 300 km of the islands. Assuming an even distribution of foraging effort within their respective foraging ranges, rates of food transferred to penguins in November ranged from 4.1 × 10−3 g m−2 d−1 for macaroni penguins to 1.24 × 10−2 g m−2 d−1 for king penguins. In mid-July, transfer rates to king and gentoo penguins were 3.9 × 10−3 g m−2 d−1 and 6.7 × 10−3 g m−2 d−1, respectively. The importance of pelagic myctophid fish to penguin populations at the Prince Edward Islands is clear.
Population dynamics of marine benthic invertebrates in Antarctic and subantarctic environments: are there unique adaptations?
Authors: Brey Thomas , Clarke Andrew
Published: December 2007

Data on the growth (20 species) and productivity (19 species) of Antarctic and subantarctic macrobenthos were compiled from published and unpublished sources. Differences in the production/biomass (P/B) ratio between Antarctic, Arctic and non-polar populations were examined using a set of 363 data arrays (327 non-polar, 26 Antarctic, 10 Arctic). Each array contained annual P/B ratio, mean individual body mass, geographical latitude, water depth, bottom water temperature and the nominal variables TAXON (Mollusca, Crustacea, Polychaeta, Echinodermata) and REGION (Antarctic, Arctic, non-polar). The P/B ratio was found to vary with body mass, taxon, temperature and water depth. P/B ratios of Antarctic and Arctic populations were significantly lower than those of non-polar populations. For Antarctic populations this difference could be explained completely by the effects of temperature and water depth. The strikingly high biomass of many Antarctic benthic communities is probably related to adaptations to low and oscillating food levels, and particularly to the low maintenance energy requirement associated with the low ambient temperature.
Thraustochytrid protists in Antarctic fast ice?
Authors: Riemann Franz , Schaumann Karsten
Published: December 2007

Sea ice provides a habitat for a conspicuous and productive assemblage of autotrophic microalgae and for heterotrophs ranging from bacteria to vertebrates (Horner 1990, Garrison 1991). With the exception of a reference to chytridiaceous fungi that were found infecting Arctic ice diatoms (Horner 1977) and a note in a cruise report (Schnack-Schiel 1987, p. 153), it appears that fungi and similar organisms have until now not been mentioned as members of the heterotrophic sea ice community. In the present short note we report on the abundant occurrence of apparently thraustochytrid fungus-like protists associated with mucilage tubes of pennate diatoms, encountered in the lower section of a fast ice core drilled close to the southern shelf ice margin of the Weddell Sea.
Geochemistry of Palaeozoic–Mesozoic Pacific rim orogenic magmatism, Thurston Island area, West Antarctica
Authors: Leat Philip T. , Storey Bryan C. , Pankhurst Robert J.
Published: December 2007

Thurston Island, and the adjacent Eights Coast and Jones Mountains, record Pacific margin magmatism from Carboniferous to Late Cretaceous times. The igneous rocks form a uniformly calc-alkaline, high-alumina, dominantly metaluminous suite; some relatively fractionated granitoids are mildly peraluminous. The magmas were hydrous, a result of subduction. Gabbros have compositions outside the range of mafic volcanic and hypabyssal rocks, as a result of cumulate processes. Trace element compositions of the mafic magmas range from a low La/Yb, Th/Ta end-member close to E-MORB in composition, perhaps contaminated by crust, to a high La/Yb, Th/Ta end-member, close to shoshonite, with strong magmatic arc trace element character. This variation may be a result of mixing of tholeiitic and shoshonitic end-members. Most silicic rocks could have been generated batch-wise from mafic magmas by fractional crystallization of a phenocryst assemblage dominated by plagioclase, pyroxene ± amphibole, as seen in the cumulates. Cessation of magmatism at about 90 Ma approximately coincided with collison of a spreading centre between the Phoenix and Pacific oceanic plates with the continent margin subduction zone. The rifting of New Zealand from West Antarctica and associated extension probably was responsible for emplacement of a coast-parallel Cretaceous dyke swarm.
Baseline atmospheric mercury studies at Ross Island, Antarctica
Authors: de Mora S. J. , Patterson J. E. , Bibby D. M.
Published: December 2007

The first extended baseline studies of total gaseous mercury (TGM) and dimethylmercury (DMM) in Antarctica are reported. Mean TGM concentrations of 0.52, 0.60 and 0.52 ng m−3 were obtained for three consecutive years at the southern tip of Ross Island (77°S). The levels of DMM in Antarctica are less than 10% of the TGM, and frequently fall below the limit of detection. These results represent the lowest TGM concentrations recorded globally and extend into polar regions the observation of a decrease in atmospheric mercury concentration with increasing latitude.
The relationship between water chemistry and surface sediment diatom assemblages in maritime Antarctic lakes
Authors: Jones V. J. , Juggins S. , Ellis-Evans J. C.
Published: December 2007

Maritime Antarctic freshwater lakes and their catchments are inherently simple systems in an environment which is characterized by strong seasonality. Such lakes offer excellent opportunities to study the interaction of water chemistry and plant communities. The response of diatom species to environmental gradients was assessed by constructing a diatom and water chemistry dataset from 59 lakes at two locations (Livingston Island, South Shetland Islands and Signy Island, South Orkney Islands). Results indicate that diatom species abundance is predominately related to nutrient and salinity gradients. The dataset will be used to create transfer functions which can be applied to sediment core diatom assemblages to reconstruct historical patterns of lake chemistry.
Volatile organic compounds from Organic Lake, an Antarctic, hypersaline, meromictic lake
Authors: Roberts N. J. , Burton H. R. , Pitson G. A.
Published: December 2007

Five volatile organic compounds were identified throughout 1991 in the hypolimnion of Organic Lake. These were dimethylsulphide (DMS), dimethyldisulphide (DM2S), dimethyltrisulphide (DM3S), dimethyltetrasulphide (DM4S) and phenol. The concentration of these compounds increased with lake depth. The concentration of DMS and DM2S was higher in the sediment than in the water column. Carbon disulphide occurred only in the sediment. DMS was the only volatile organic compound detected in the epilimnion of the lake, where its concentration increased from winter onwards. The source of DMS was not dimethylsulphoniopropionate (DMSP). This was determined by hydroxylation of the sample with NaOH. There was no change in the concentration of DMS but the concentration of DM2S increased dramatically while the concentrations of DM3S and DM4S decreased concomitantly. This has important implications in the estimation of DMS derived from DMSP by hydroxylation when organic polysulphides are also present. The stability of the hypolimnion of Organic Lake was reflected by the lack of change in temperature, density, redox potential and the relatively constant concentration of volatile organic compounds throughout the year. Potential sources of the volatile organic compounds are discussed in relation to the isolated nature of the lake.
Implications of the break-up of Wordie Ice Shelf, Antarctica for sea level
Authors: Vaughan David G.
Published: December 2007

Temperature records in the Antarctic Peninsula have shown a climatic warming of 1.5°C over the past 30 years and a number of ice shelves have retreated. The most dramatic retreat has been that of Wordie Ice Shelf which has undergone a catastrophic disintegration since the 1960s. Understanding the cause and mechanism of the break-up may provide important clues to the fate of ice shelves farther south which, it has been suggested, help to stabilize the West Antarctic Ice Sheet. The break-up of Wordie Ice Shelf has been analysed using Landsat and SPOT imagery. These observations show that the relative contribution of the various input glaciers to the grounding line flux has not altered during the break-up. This means that the effect of the rapid and almost complete removal of the ice shelf has not been transmitted upstream and is not causing a rapid increase in velocities on the input glaciers. The volume of grounded ice in the catchment of Wordie Ice Shelf will thus, be largely unaffected by the break-up and there will be no significant contribution to sea level change. Since other ice shelves around the Antarctic Peninsula are also fed by relatively steep mountain glaciers the effect of the loss of the ice shelves on sea level would be likely to be similarly small.
The importance of the Southern Ocean cephalopod fauna
Authors: Okutani Takashi
Published: December 2007

The Southern Ocean is probably the last frontier in the field of marine biology. This huge oceanic region is the scene of a very efficient production system yielding high levels of biomass. Within the Southern Ocean food chain the important and conspicuous role played by Antarctic krill is well documented but there is another group of key animals, rarely conspicuous and much less well understood that play a most important intermediate role in the food chain. Although field scientists working in the Southern Ocean have observed an abundant and diverse squid fauna in the diet of vertebrate predators, Antarctic squid have seldom been seen alive. This is in contrast to the situation in seas at lower latitudes where schools of neritic and oceanic squid are regularly encountered at the surface. Marine scientists have rarely been successful in catching Antarctic squid, using either towed nets or jigs, but it has been estimated that standing stock biomass of these organisms in the Southern Ocean may be as high as 100 million tonnes based on an estimate of 30 million tonnes consumed by vertebrate predators. This is clearly a significant resource when compared to the annual catch of the world's fisheries (mostly finfish) which, according to current FAO statistics, amounts to some 100 million tonnes.
Southern Ocean cephalopods: life cycles and populations
Authors: Roper Clyde F.E.
Published: December 2007

Try to imagine a lecture hall in King's College filled with zoologists discussing the lives and ways of cephalopods of the Southern Ocean. A few years ago such a dedicated gathering would have been unimaginable for any Southern Ocean invertebrate save for the ubiquitous euphausid, Euphausia superba. How things have changed under the influences of a major international squid fishery and international collaborative research programmes.
Cephalopods in the diets of three odontocete cetacean species stranded at Tierra del Fuego, Globicephala melaena (Traill, 1809), Hyperoodon planifrons Flower, 1882 and Cephalorhynchus commersonii (Lacepede, 1804)
Authors: Clarke Malcolm , Goodall Natalie
Published: December 2007

Cephalopod remains from the stomachs of four pilot whales Globicephala melaena (Traill, 1809), two bottlenose whales Hyperoodon planifrons Flower, 1882 and eight Commerson's dolphins Cephalorhynchus commersonii (Lacepede, 1804) stranded in Tierra del Fuego, Argentina were identified and measured. A total of 3365 lower beaks (mandibles) were identified and measured and from the rostral, crest and hood length, total wet and dry mass, mean mass and mean mantle length for each taxon were estimated. Over 68% of the cephalopods eaten by the pilot whales and all cephalopods eaten by the bottlenose whales were oceanic squid species (oegopsids). The Commerson's dolphins had only eaten shelf species of the families Loliginidae (97.5%) and Octopodinae (2.5%). Sixteen cephalopod families comprising 23 species were represented. In samples from Globicephala melaena, Loligo gahi represented 31% by number and 7.1% by estimated dry mass, Histioteuthis eltaninae, 29% by number and 4.9% by dry mass and the onychoteuthid Moroteuthis ingens 17.2% by number and 51.5% by dry mass. In samples from Hyperoodon planifrons, Histioteuthis eltaninae represented 24.0% of cephalopods by number but only 5.2% by dry mass, Taonius pavo 53% by number but only 2.5% by dry mass and the large onychoteuthid Kondakovia longimana only 2.5% by number but 65.8% by dry mass. In samples from Cephalorhynchus commersonii, the neritic Loligo gahi contributed 97.4% by number and 97% by dry mass and a neritic octopodinid contributed the rest of the cephalopod part of the diet. While the cephalopods contributed the major part of the diets of these particular cetaceans, other remains included fish and polychaete worms.
Dead or alive, night or day: how do albatrosses catch squid?
Authors: Croxall J.P. , Prince P.A.
Published: December 2007

For many albatross species squid are important prey. Whether albatrosses depend on scavenging (e.g. of vomit from cetaceans, post-spawning die-offs or fishery waste) or on live-capture of squid (e.g. via diel vertical migrations in association with aggregations of squid prey) is controversial. This review of the nature of interactions between squid and the four species of albatross breeding at South Georgia uses data on the foraging range, methods and timing of feeding of the albatrosses in relation to the size, distribution, buoyancy characteristics (floaters or sinkers), bioluminescence and prey of the squid and access to fishery waste. We conclude that most evidence for scavenging needs critical re-evaluation; nevertheless, whereas wandering albatrosses and possibly light-mantled sooty albatrosses probably depend significantly on scavenged squid, black-browed and especially grey-headed albatrosses are unlikely to do so.
Statolith microstructure of seven species of Antarctic squid captured in Prydz Bay, Antarctica
Authors: Jackson G.D. , Lu C.C.
Published: December 2007

The statolith microstructure was examined from seven species of seven families of Antarctic squid captured in Prydz Bay (n=23). Five of the species (Kondakovia longimana, Psychroteuthis glacialis, Brachioteuthis sp., Mastigoteuthis psychrophila, Galiteuthis glacialis) had very clear statolith growth increments which could be enumerated from the nucleus to the statolith margin. These increments were similar in appearance to daily statolith increments in other temperate and tropical squids. Psychroteuthis glacialis also had two distinct zones which may reflect growth during the pelagic and demersal phases of the life cycle. Total statolith increment counts were not possible on two of the species (Bathyteuthis abyssicola and Alluroteuthis antarcticus). The statolith microstructure of Bathyteuthis abyssicola had some very faint increments near the nucleus but increments were not visible in most of the statolith microstructure, while the statolith microstructure of A. antarcticus was indistinct in the nuclear region (possibly due to the formation of a second primordium during ontogenesis). Future research may reveal that statolith increments are useful tools for Antarctic squid age and growth studies.
Eledonine octopods from the Southern Ocean: systematics and distribution
Authors: Kubodera Tsunemi , Okutani Takashi
Published: December 2007

Fortyfour octopods from bottom trawls off Palmer Archipelago, south-eastern Argentina, south-eastern New Zealand, Crozet Islands and Showa Station were examined. Three species of Pareledone, three species of Graneledone and one species of Megaleledone were identified. All were characterized by having a single row of arm suckers. Mature males of P. harrissoni, P. adelieana and G. macrotyla were recorded for the first time. Hectocotylus and male reproductive organs of these species are described. On the basis of previously reported distributions and the present localities, P. charcoti, P. harrissoni and P. adelieana appear to have circumantarctic distributions. G. macrotyla was identified but the other two species of Graneledone could not be identified to species level because of the poor systematic state of this genus.
Problems associated with ageing squid from their statoliths: towards a more structured approach
Authors: Lipinski Marek R. , Durholtz M. Deon
Published: December 2007

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.
Contribution to the biology of squid in the Prydz Bay region, Antarctica
Authors: Lu C.C. , Williams R.
Published: December 2007

The teuthoid fauna of the Prydz Bay region of the Southern Ocean (Indian Ocean sector) has been studied based on the material collected from 1981–1991 using a rectangular midwater trawl (RMT-8), pelagic trawl (IYGPT), and bottom trawl. Eight species of squid have been recognized: Brachioteuthis sp., Kondakovia longimana, Bathyteuthis abyssicola, Psychroteuthis glacialis, Alluroteuthis antarcticus, Mastigoteuthis psychrophila, Mesonychoteuthis hamiltoni and Galiteuthis glacialis. Size frequency distribution, geographical and vertical distributions of each species as well as diets of common species are analysed. There is no evidence of a diel vertical migration but ontogenetic descent appears to occur in P. glacialis and G. glacialis. Antarctic krill, Euphausia superba and the Antarctic silverfish, Pleuragramma antarcticum are important prey for most species with cannibalism occurring in P. glacialis, A. antarcticus and M. hamiltoni. Equations for calculating total weight from mantle length, and mantle length and total weight from upper and lower rostral length are provided for B. abyssicola, P. glacialis, A. antarcticus, M. psychrophila, and G. glacialis.
Squid diet of emperor penguins (Aptenodytes forsteri) in the eastern Weddell Sea, Antarctica during late summer
Authors: Piatkowski Uwe , Pütz Klemens
Published: December 2007

The data presented provides new information on the distribution of Antarctic squids and on the summer diet of the emperor penguins. The diet of 58 adult emperor penguins (Aptenodytes forsteri) on the fast ice of the Drescher Inlet, Vestkapp Ice Shelf (72°52′S, 19°25′W) in the eastern Weddell Sea was investigated. Prey consisted principally of squid, fish, krill, amphipods and isopods. Squids were identified by the lower beaks and allometric equations were used to estimate the squid biomass represented. Beaks occurred in 93% of the stomach samples. Each sample contained a mean of 27 beaks (range 1–206). Ninety-two percent of the squids could be identified by the lower beaks and belonged to four families (Onychoteuthidae, Psychroteuthidae, Neoteuthidae and Gonatidae). The most abundant squid was Psychroteuthis glacialis which occurred in 52 samples with lower rostral lengths (LRL) ranging from 1.4–7.2 mm. Forty-five samples contained Alluroteuthis antarcticus (LRL range 1.8–5.8 mm), 17 Kondakovia longimana (LRL range 4–12.1 mm), and four Gonatus antarcticus (LRL range 4.1–6.1 mm). In terms of biomass K. longimana was the most important species taken by the penguins comprising 50% of total estimated squid wet mass (245348 g) in 1990 and 48% in 1992 (154873 g). However, if only fresh beaks were considered for estimations of squid consumption, i.e. beaks that have been accumulated for not longer than 5–6 days in the stomachs, squid diet was of minor importance. Then total squid wet mass accounted for only 4809 g in 1990 and 5445 g in 1992 which implies that one penguin took c.30 g squid d−1 with P. glacialis and A. antarcticus being the most important by mass. The prey composition suggests that emperor penguins take squid at the steep slope regions of the eastern Weddell Sea.
Environment: the key to understanding the South African chokka squid (Loligo vulgaris reynaudii) life cycle and fishery?
Authors: Roberts M.J. , Sauer W.H.H.
Published: December 2007

This paper explores effects of environmental variability on the life cycle of the chokka squid, Loligo vulgaris reynaudii in South Africa, particularly the effect of physical and chemical influences on adult distribution, and the availability of spawning aggregations to the local jig fishery. The following hypotheses are presented: 1) temperature, dissolved oxygen and currents have a direct effect on the demersal distribution of adult chokka on the feeding grounds, but this is restricted to the west coast where environmental conditions are more extreme relative to the south coast, 2) chokka catches increase in proportion to the extent of coastal upwelling, 3) spawning behavior along the inshore regions (<50m) is strongly influenced by turbidity near the seabed. High turbidity forces the spawning popuation to lay their eggs in deeper waters, and are thus not available to the jig fishery. 4) El Niño – Southern Oscillation (ENSO) events are linked with large fluctuations in the availability of spawning squid aggregations to the inshore jig fishery.
Predation on Gonatus antarcticus by Falkland Islands seabirds
Authors: Thompson K.R.
Published: December 2007

Recent studies of Falkland Islands seabird diets have found that Gonatus antarticus is a major prey item for a number of penguin species. Rockhopper (Eudyptes chrysocome), gentoo (Pygoscelis papua) and Magellanic (Spheniscus magellanicus) penguins breeding in the Falklands are estimated to consume several thousand million Gonatus per annum, with mean dorsal mantle lengths of 28–42 mm. Aspects of the distribution and growth of the G. antarcticus stock in the vicinity of the Falkland Islands are discussed.
Relative growth of paralarvae and juveniles of Illex argentinus (Castellanos, 1960) in southern Brazil
Authors: Vidal Erica A.G.
Published: December 2007

Ommastrephid squids undergo remarkable morphological change during the transition from planktonic paralarvae to adults. These changes are characterized by changes in the relative growth of body dimensions and mark phases and stages in post-embryonic development. The following morphometric characters of paralarval and juvenille Illex argentinus ranging in size from 1–55 mm ML were measured: dorsal mantle length (ML), mantle width (MW), head width (HW), eye diameter (ED), right arm lengths (AIL) (AIIL) (AIIIL) (AIVL), proboscis length (PL), proboscis division (PD), fin length (FL), fin width (FW), right tentacle length (TL), club length (CIL), dactylus length (DL) and carpus + manus length (CML). The relative growth of AIL, AIIL, AIIIL, HW and ED, showed discontinuities at c. 14 mm ML, while AIL, AIIL, AIIIL, AIVL, FL, and TL showed other discontinuities at c. 28 mm ML. These discontinuities seem to be related to the activity and ability of the animal to obtain food and survive in different environments. At an early phase (1–14 mm ML), there is a rapid development of the arms, suckers and fins. In the second stage (14–28 mm ML) there is a rapid development of the tentacles and clubs. In the third (>28 mm ML), the juvenile grows more in length in relation to other body parts. No morphological change, besides the proboscis division, takes place at the end of rhynchoteuthion stage. This may indicate the necessity for re-evaluation of the paralarval phase in Ommastrephidae.
International stations or international research?
Authors: Walton D W H
Published: December 2007

There has been much adverse comment over recent years, especially by those with little practical Antarctic knowledge, of the apparent need to establish a national Antarctic station in order to gain Consultative Status at Treaty Meetings. Why, cry all these querulous voices, can't you co-operate more effectively, stop establishing new national stations and share your stations? Why are there not international rather than national stations in the Antarctic — surely that should be the aim of the Treaty Parties?
13C NMR analysis of Antarctic cryptogam extracts
Authors: Chapman B. E. , Roser D. J. , Seppelt R. D.
Published: December 2007

Water soluble compounds were extracted from the dominant cryptogams of the Windmill Islands, Wilkes Land, and compared with standard polyols, sugars and amino acids using 13C nuclear magnetic resonance (NMR) spectroscopy. Previous findings for sugars and polyols from gas liquid chromatorgraphy were validated and extended. Arabitol, ribitol and mannitol were confirmed as the major soluble carbohydrate compounds in all lichen species examined. Sucrose, fructose and glucose, but no polyols were detected in two species of moss. Sorbitol was confirmed as a major component of the algae Prasiola crispa and Schizogonium murale. Mesotaenium bergrenii was confirmed to contain sucrose and glucose. No significant quantities of sugars or polyols or any other compound were found in extracts of the red snow alga Chloromonas sp.1. Amino acids were detected in the majority of cryptogam samples and were particularly abundant in the algae P. crispa and S. murale. In the latter species the total identified acids ranged from 13.5–66mg g-1 dry weight. In addition to the common amino acid components of proteins, betaine and γ-amino-butyric acid were detected, the latter being particularly abundant, being found widely in the moss, lichen and algae. Several unknown carbohydrates were characterized. Usnea sphacelata, U. antarctica and Pseudephebe minuscula contained a deoxy-hexitol, Grimmia antarctici contained resonance peaks consistent with a trisaccharide containing a sucrose moiety and Umbilicaria decussata possibly contained a glucose-arabitol dimer. 13C NMR was confirmed as a powerful tool for the characterization of low molecular weight constituents of Antarctic cryptogams.
The effect of human activities on moisture content of soils and underlying permafrost from the McMurdo Sound region, Antarctica
Authors: Campbell I. B. , Claridge G. G. C. , Balks M. R.
Published: December 2007

Soils and the underlying permafrost from undisturbed sites and sites that had been disturbed by construction activities at Marble Point and Pram Point in the McMurdo Sound region were sampled from excavated pits and drill cores. Gravimetric moisture (ice) contents and particle size distribution were determined. Volumetric moisture contents were calculated from these results. At undisturbed sites soil moisture contents within the active layer (to c. 60 cm depth) were low and ranged from 0.5% by weight at the soil surface to 10% above the permafrost. The permafrost was generally completely saturated with ice, but sometimes contained considerable excess ice, with ice contents rising as high as 80% by volume. At disturbed sites, soil moisture contents within the active layer were similar to those of the undisturbed sites (generally <10% by weight) but within the permafrost, moisture contents were lower and less variable than in the undisturbed sites, rarely exceeding 20% by weight. The release of considerable quantities of water from the permafrost as a result of land disturbance during construction activities caused stream flows, soil shrinkage, land slumping and salinisation, resulting in significant permanent environmental damage. At Marble Point there has been no significant re-establishment of icy permafrost in the disturbed soils in the 30 years since land disturbance occurred.
Seasonal abundance of Halomonas meridiana, Halomonas subglaciescola, Flavobacterium gondwanense and Flavobacterium salegens in four Antarctic lakes
Authors: James S. R. , Burton H. R. , McMeekin T. A. , Mancuso C. A.
Published: December 2007

Indirect immunofluorescence was used to quantify the seasonal variation of four halophilic aerobic Antarctic bacteria in Antarctic saline lakes from July 1990 to January 1991. Antibodies were raised against type strains from the Australian Collection of Antarctic Microorganisms. During summer, all four serogroups were identified in the aerobic waters of lakes with total dissolved salts above 61%. Maximal abundances of Halomonas meridiana, H. subglaciescola and Flavobacterium gondwanense serogroups were observed at discrete depths within the water column in the two most hypersaline lakes at about midsummer, coincident with the time of maximum sunlight and the commencement of the summer thaw. At this time the Halomonas spp. serogroups comprised up to 40% of the total bacteria and the F. gondwanense serogroup up to 10% of the total bacteria. The F. salegens serogroup was in low numbers (>2% of total bacteria) in some aerobic waters. Up to 2% of the total bacterial populations in the lakes were autofluorescent or stained non-specifically. Dissolved organic carbon values were measured throughout the sampling period and correlated well with total bacterial numbers but not with changes in species composition. Change in species abundance, as indicated by immunofluorescence, was not reflected in the total bacterial count, indicating compositional change of the total bacterial population.
Mitochondrial DNA variation of Champsocephalus gunnari Lönnberg (Pisces: Channichthyidae) stocks on the Kerguelen Plateau, southern Indian Ocean
Authors: Williams R. , Smolenski A. J. , White R. W. G.
Published: December 2007

The distribution of the icefish Champsocephalus gunnari on the Kerguelen Plateau is confined to the inner shelves of Heard and Kerguelen islands and outlying banks where the water depth is less than 350 m. For fisheries management purposes, it is necessary to know whether fish from the various shelves and banks belong to one single or several separate populations. Analysis of the mitochondrial DNA of fish from various localities using restriction endonclease enzymes revealed no significant genetic heterogeneity between any of the localities. This does not preclude the existence of isolated stocks at the present time but indicates that the populations have been separated too recently for genetic isolation to be manifested, or that low-level interchange of fish between the populations may be maintaining genetic homogeneity.
U-Pb zircon age of the metavolcanic rocks of Fisher Massif (Prince Charles Mountains, East Antarctica)
Authors: Beliatsky B. V. , Laiba A. A. , Mikhalsky E. V.
Published: December 2007

Fisher Massif is believed to represent less metamorphosed portions of an extensive Proterozoic mobile belt, and is composed of metavolcanic rocks of different compositions and numerous intrusive bodies. U-Pb dating of six zircon fractions recovered from metavolcanic rocks of intermediate to acidic compositions defines growth time at c.1300 Ma with prominent Pb losses at 364 Ma and in recent time. Grain morphologies do not provide unequivocal genetic evidence, but an igneous origin for the grains studied is the most probable. The dates obtained probably reflect igneous activity be co-eval with mafic dyke emplacement event elsewhere in ancient East Antarctic cratonic blocks.
Radiocarbon dating of lacustrine and marine sediments from the Bunger Hills, East Antarctica
Authors: Melles Martin , Verkulich Sergey R. , Hermichen Wolf-D.
Published: December 2007

Radiocarbon dating was carried out on the total organic carbon of 19 lacustrine and marine sediment samples from the Bunger Hills. The results indicate that radiocarbon contamination is negligible throughout two sediment sequences from a fresh water lake. In contrast, two sequences from marine basins are irregularly influenced by the Antarctic Marine Reservoir Effect, which today amounts to more than 1000 years, depending on the degree of dilution with meltwater. All dated sediments were deposited during Holocene time.
The structural evolution of the Rauer Group, East Antarctica: mafic dykes as passive markers in a composite Proterozoic terrain
Authors: Sims John P. , Dirks Paul H. G. M. , Carson Chris J. , Wilson Chris J. L.
Published: December 2007

Archaean gneisses in the Rauer Group of islands, East Antarctica, record a prolonged history of high-grade deformational episodes, many of which predate that identified in mid-Proterozoic gneisses. Eleven generations of mafic dykes, belonging to discrete chemical suites, have been used as relative time markers to constrain this deformational history. Based on the timing of intrusion with respect to structures, dykes in the Rauer Group have been correlated with largely undeformed and dated dyke suites in the adjacent Vestfold Hills. This has allowed absolute ages to be inferred for the early- to mid-Proterozoic mafic dyke suites in the Rauer Group, and a correlation of the interspersed structural events. Most structures in the Rauer Group, however, developed in response to high-grade progressive deformation at approximately 1000 Ma. During this deformational episode, strains were repeatedly partitioned into sub-vertical, noncoaxial, high-strain zones recording NW-directed sinistral transpression, that separated zones of lower strain dominated by coaxial folding with axes parallel to the shear direction. Three additional mafic dyke suites intruded during this deformation which was followed by three stages of brittle-ductile deformation and a final suite of lamprophyre dykes. Due to the numerous intrusive time markers, the Rauer Group serves as an excellent illustration of how complicated gneiss terrains may be.
A probable Early Triassic age for the Miers Bluff Formation, Livingston Island, South Shetland Islands
Authors: Willan R. C. R. , Pankhurst R. J. , Hervé F.
Published: December 2007

Fifteen samples of very low-grade mudstones from two widely separated sections in the Miers Bluff Formation on Hurd Peninsula yield an Rb-Sr errorchron (MSWD=8.9) corresponding to an age of 243 ± 8 Ma. This age is interpreted as representing effective homogenization, on a kilometres scale, during turbidite deposition and diagenesis in early Triassic times. The initial 87Sr/86Sr ratio 0.7085 ± 0.0003 represents a mature crustal source and is consistent with the re-working of material comparable to that eroded from the Chilean fore-arc accretionary complex. Four further samples, collected near to a zone of quartz-carbonate veins, lie to the right of the errorchron, with two samples having unusually low Sr contents. These samples fall on a 113 Ma reference line and indicate metasomatic disturbance in Cretaceous times. Metasomatism was probably related to hydrothermal alteration accompanying widespread silicification and quartz veining on western Hurd Peninsula. A mid-to late Cretaceous age for metasomatic disturbance agrees with field relations which indicate that the hydrothermal activity preceded or was coeval with the mid- to late Cretaceous period of volcanism on Livingston Island. Hence the hydrothermal rocks are not related to the Eocene Barnard Point pluton, as previously suggested.
Interpreting the Environmental Protocol — a recipe for international confusion?
Authors: Walton D W H , Thomson M R A
Published: December 2007

Turning international agreement into national law has never been rapid or simple. Each country has its own parliamentary procedures, its own legal system and its own cultural interpretation of what the words in the international agreement actually mean. Last but not least, the importance attached to implementing Treaty law is clearly different between countries, as the amazingly patchy implementation of existing Treaty Recommendations shows.
Wind field effect on hydrography and chlorophyll dynamics in the coastal pelagial of Admiralty Bay, King George Island, Antarctica
Authors: Brandini Frederico Pereira , Rebello Jaqueline
Published: December 2007

The vertical distribution of physicochemical parameters and Chl a at a fixed station in Admiralty Bay (King George Island, South Shetland Islands) was recorded over 73 days during the summer of 1988/89. Temporal variations in Chl a and nutrient stocks in the euphotic zone were associated with changes in the wind/hydrological regime. Northerly winds of late December and early January moved the surface layers towards the outerbay, during which time the chlorophyll stocks remained low in the euphotic zone. Turbulence induced by southerly winds in the second half of January resuspended sediments and benthic diatoms in the shallow (0–20 m) inner inlets of the bay, increasing turbidity and nutrient concentrations at the surface. During the first half of February wind relaxation caused the mass sedimentation of previously resuspended benthic diatoms increasing chlorophyll and phaeopigments in the subsurface layers in deeper sections of the bay. Although turbulence limits phytoplankton biomass accumulation in open waters of the Antarctic, it may have a positive effect (increasing chlorophyll biomass of benthic origin) in coastal pelagic environments during late summer.
Regional variations in bio-optical properties of the surface waters in the Southern Ocean
Authors: Fenton Nicola , Priddle Julian , Tett Paul
Published: December 2007

Values of attenuation coefficient, Kd(λ), for five visible wavelengths are reported for 14 sites around South Georgia and the Bransfield Strait, in the Southern Ocean. The mean chlorophyll-plus-phaeopigment concentrations in the upper 30 m of the water column ranged from 0.32–6.633 mg m−3 with one particularly high mean value of 31 mg m−3. Partition of attenuation between chlorophyll (Kc) and other factors in the water column (Ko) indicated that the spectral character of Ko in the Bransfield Strait was consistent with absorption by non chlorophyll-like pigments (Gelbstoff). Values were significantly different between the two areas. Values of the specific attenuation coefficient due to pigment concentration (Kc) were small compared to temperate values. These data support other studies in suggesting that the application of remotely sensed ocean colour data to global biogeochemical surveys requires the development of regional algorithms.
Benthic associations of the shallow hard bottoms off Terra Nova Bay, Ross Sea: zonation, biomass and population structure
Authors: Gambi Maria Cristina , Lorenti Maurizio , Russo Giovanni F. , Scipione Maria Beatrice
Published: December 2007

Quantitative and semi-quantitative samples of phyto- and zoobenthic organisms were collected by SCUBA diving at five stations along a depth transect from 0.5–16 m on the shallow hard bottoms off Terra Nova Bay, Ross Sea, Antarctica. The benthic associations were dominated by two macroalgal species (Iridaea cordata and Phyllophora antarctica) and by few animal taxa (mainly polychaetes, molluscs and peracarid crustaceans). Distribution at the community and species levels revealed a well-defined zonation pattern as a function of depth, governed mainly by sea ice scouring and melting. Zonation of vagile fauna was also affected by the effects of covering and architecture of the two dominant macroalgae. Species richness and diversity were higher in the Phyllophora-associated community, where habitat complexity and sheltering were higher. The highest faunal abundance (over 82 000 ind.m−2) and biomass (macroalgae and fauna wet weight 2392 g m−2) were recorded at 2 m depth in association with the Iridaea covering, where the harsher environmental conditions select a few taxa. The biomass values, even if underestimates of the whole community standing crop, are among the highest recorded in shallow austral biotopes. An autoecological and demographic analysis of the most abundant animal species revealed for some species (e.g. Laevilitorina antarctica and Paramoera walkeri) a quite complex population structure with up to three size classes, including juveniles. In some species, the cohort of juveniles showed a well-defined depth preference probably related to sheltering by the macroalgae. As a whole, the species analyzed showed various and contrasting reproductive strategies, despite the fact that the environmental conditions along the transect were relatively similar and quite selective.
Epilithic macrolichen vegetation of the Argentine Islands, Antarctic Peninsula
Authors: Gremmen N.J.M. , Huiskes A.H.L. , Francke J.W.
Published: December 2007

Classification of 162 sample plots of lichen vegetation from the Argentine Islands region, Antarctica, yielded two main groups, the Usnea complex and the Mastodia-Rinodina complex, comprising four and six subordinate communities, respectively. Communities of the Usnea complex typically occur in inland sites with steep slopes, characterized by low chloride, ammonia and phosphate concentrations. Communities of the Mastodia-Rinodina complex occur close to the shore and in areas occupied by birds, where concentrations of chloride, ammonia and phosphate were relatively high. Within each vegetation complex species composition is related to factors indicating nutrient status (chloride and ammonia concentration, distance from the sea), as well as to variables indicating different microclimatic conditions (elevation, aspect, exposure, moisture, and gradient). In canonical correspondence analyses of the data a large part of species variation could not be explained by the environmental variables studied (elevation, gradient, slope aspect, distance from the sea, direction of the sea, presence of guano, exposure, moisture, chloride, ammonia, phosphate and nitrate concentrations). It is suggested that temporal variability in mineral concentrations and the lack of information on differences in length of the growing season at the sample sites are, to a large extent, responsible for this.
Holocene glacier variations in the Terra Nova Bay area (Victoria Land, Antarctica)
Authors: Baroni Carlo , Orombelli Giuseppe
Published: December 2007

Information on Holocene glacier variations in Antarctica is limited and sometimes contradictory. However, if the behaviour of the glaciers during the recent past can be clarified, their sensitivity to climatic changes can be evaluated and their contribution to the sea level variation may be predicted. Through the study of local glaciers and floating ice shelves in the Terra Nova Bay area, new information has been gathered. Between 7500 and 5000 yr B.P., after the glacial retreat which followed the Last Glacial Maximum, the Nansen Ice Sheet and the Hells Gate ice shelf were a few kilometres less extensive than they are now. During the second half of the Holocene, both the local glaciers and the ice shelves advanced to positions that were more extensive than their present ones, although not all the variations are adequately dated. A retreat phase of the Edmonson Point glacier occurred during late Middle Ages between 920–1050 A.D. and 1270–1400 A.D. as documented by ten 14C dates obtained from shells in ice-cored moraines. A subsequent advance occurred after the 15th century in a period corresponding to the Little Ice Age.
Palaeoecology of the Early Permian strata at Heimefrontfjella, Dronning Maud Land, Antarctica
Authors: Guy-Ohlson Dorothy , Lindström Sofie
Published: December 2007

Palaeopalynological studies form an integral part of the geological investigation of the Late Paleozoic sedimentary history of Dronning Maud Land. During the examination of organic residues prepared from different localities at Heimefrontfjella, the freshwater green alga Botryococcus was found. Exceptionally well-preserved colonies of Botryococcus were recorded in several samples at two sections of Early Permian age, Lidkvarvet and Locality A. These colonies vary in form and stage of development. By analogy with observations on recent material the following palaeoecological conclusions are drawn: 1) varying environmental and climatic conditions over a length of time existed at Lidkvarvet, and 2) very short ephemeral aquatic conditions existed intermittently at Locality A.
Petrography and provenance of the Marambio Group, Vega Island, Antarctica
Authors: Pirrie Duncan
Published: December 2007

Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.