bluuebunny/crossref_metadata_2025 huggingface dataset:
Snow surface temperatures in West Antarctica
Authors: Morris E.M. , Vaughan D.G.
Published: December 2007

Snow temperatures measured at around 10 m depth over the period 1957–1992 have been used to derive a map of mean annual snow surface temperature corrected to sea level over the Antarctic Peninsula and Filchner-Ronne Ice Shelf. Multiple linear regression analysis has been used to calculate rates of change with latitude, longitude, altitude and time, for data to the west and east of the topographic divide running along the spine of the Antarctic Peninsula. Climate warming on the Filchner-Ronne Ice Shelf follows the trend observed at Halley Bay, a coastal station nearby. High spatial variability leads to uncertainty in the temporal trend for mean annual snow surface temperature in the Antarctic Peninsula but there is some indication that the large trends observed at Faraday and Marguerite Bay, two stations on the west coast of the peninsula, are attenuated inland.
The aquatic testate amoebae fauna of the Strømness Bay area, South Georgia
Authors: Beyens L. , Chardez D. , De Baere D. , Verbruggen C.
Published: December 2007

Forty six taxa of testate amoebae were found in 45 samples of aquatic environments ranging from small pools to lakes. Four assemblages were distinguished which, to some degree, can be related ecologically to different pH ranges, and to differences in the habitat structure. The Nebela collaris assemblage occurs in acid pools mostly vegetated with mosses. The Centropyxis gibba gibbosa–Euglypha tuberculata–Difflugia globularis/globulus assemblage is found in the sediments of circumneutral to slightly alkaline lakes. Both of the other assemblages are mainly found in pools, which are more (for the Trinema assemblage) or less vegetated with mosses, in slightly acid (the Difflugia penardi–Centropyxis aerophila assemblage) or circumneutral to slightly alkaline (the Trinema lineare assemblage) conditions. A generic comparison with the Arctic fauna indicates differences, especially in the role of Difflugia as a dominant genus in aquatic habitats.
Current flow in the north-west Weddell Sea
Authors: Barber Marion , Crane David
Published: December 2007

Properties of the surface and bottom circulation in the north-west Weddell and south Scotia seas in the region 59–66°S, 36–46°W are examined. The bottom currents have been recorded at different heights from 5–800 m above the seabed, and surface velocities have been obtained from the drift tracks of ARGOS buoys deployed in ice floes. The tidal regime is mixed and the power of motions at inertial frequencies is very variable and most dominant in the Scotia Sea. Flow is influenced by topography, effects of which are seen in eddy features and the damping of inertial motions in some areas. The sea ice motion is shown to be influenced by the bottom topography at very low frequencies whilst tidal periodicities observed in the north-western Weddell Sea are below the level of the noise in the region of the study. In this area the higher frequency ice motion is mainly wind driven with little of the energy being transferred to the underlying deep water.
Late Triassic plant fossils from the Prince Charles Mountains, East Antarctica
Authors: Cantrill David J. , Drinnan Andrew N. , Webb John A.
Published: December 2007

Megafloral remains recovered from the Jetty Member and the upper part of the Flagstone Bench Formation, Amery Group include Dicroidium and Pagiophyllum. Dicroidium zuberi and D. crassinervis forma stelznerianum occur with Pteruchus dubius and support a Mid to Late Triassic age. A new species of conifer, Pagiophyllum papillatus, is recognized along with an undetermined conifer pollen cone.
Geochemistry of Ferrar Dolerite sills and dykes at Terra Cotta Mountain, south Victoria Land, Antarctica
Authors: Morrison A.D. , Reay A.
Published: December 2007

At Terra Cotta Mountain, in the Taylor Glacier region of south Victoria Land, a 237 m thick Ferrar Dolerite sill is intruded along the unconformity between basement granitoids and overlying Beacon Supergroup sedimentary rocks. Numerous Ferrar Dolerite dykes intrude the Beacon Supergroup and represent later phases of intrusion. Major and trace element data indicate variation both within and between the separate intrusions. Crystal fractionation accounts for much of the geochemical variation between the intrusive events. However, poor correlations between many trace elements require the additional involvement of open system processes. Chromium is decoupled from highly incompatible elements consistent with behaviour predicted for a periodically replenished, tapped and fractionating magma chamber. Large ion lithophile element-enrichment and depletion in Nb, Sr, P and Ti suggests the addition of a crustal component or an enriched mantle source. The trace element characteristics of the Dolerites from Terra Cotta Mountain are similar to those of other Ferrar Group rocks from the central Transantarctic Mountains and north Victoria Land, as well as with the Tasmanian Dolerites. This supports current ideas that the trace element signature of the Ferrar Group is inherited from a uniformly enriched mantle source region.
Hydrocarbons and sterols in marine sediments and soils at Davis Station, Antarctica: a survey for human-derived contaminants
Authors: Green Graham , Nichols Peter D.
Published: December 2007

A survey of hydrocarbons and sterols in marine and shoreline sediments was undertaken adjacent to Davis Station in Princess Elizabeth Land, Prydz Bay, Eastern Antarctica to determine the impact of a human settlement, including a sewage outfall on the local marine environment. Soil samples from selected locations onshore were also analysed to ascertain the extent of hydrocarbon contamination emanating from fuel storage facilities and other potential sources. The faecal sterol coprostanol was detected at 13.2 μg g−1 (60% of total sterols) in sediment adjacent to the Davis sewage outfall and up to 5.0 μg g−1 on the shoreline at Davis Beach. These concentrations indicate significant faecal contamination. The absence of coprostanol in faeces from the local wildlife confirms a human origin for this sewage biomarker. Hydrocarbons on the shoreline near Davis were present at up to 5.5 μg g−1 (dry weight of sediment). Biomarker profiles indicate an anthropogenic origin for these hydrocarbons. Onshore, degraded hydrocarbons derived from Special Antarctic Blend distillate were found at relatively high levels in soils at the fuel storage depot (up to 220 μg g−1). The source of these hydrocarbons appeared to be spillage from fuel storage tanks with possible contributions from fuel pipeline leakage and vehicle useage. Concentrations of polycyclic aromatic hydrocarbons in the soils were very low, generally below 1 ng g−1 (dry weight of sediment) for individual compounds.
Factors affecting the water clarity of ponds on the McMurdo Ice Shelf, Antarctica
Authors: Pridmore R.D. , Vant W.N. , Cummings V.J.
Published: December 2007

The clarity of 39 meltwater ponds on the McMurdo Ice Shelf was determined as the horizontal viewing range of a black disc. Visual ranges varied widely from pond to pond from 0.14–5 m; so did the concentrations of optically-active constituents, including the suspended particulates, phytoplankton (10-fold variation) and inorganic suspensoids (> 100-fold), and dissolved yellow substance (10-fold). In six of the ponds the ratio of beam attenuation coefficient to total suspended solids concentration was low (< 0.6 m2 g−1) compared to that in the others (0.7–2.0 m2 g−1, suggesting that generally larger particles were present suspended in the water in these ponds. In both groups, relationships between beam attenuation and constituent concentrations indicated that much of the attenuation was due to inorganic suspensoids. Organic detritus also appeared to be important in many ponds, while phytoplankton and dissolved yellow substance were generally less important. Even though the clarity of many of the ponds was poor, their relative shallowness meant levels of underwater light were probably generally adequate for benthic plant growth.
Late Holocene advance of the Müller Ice Shelf, Antarctic Peninsula: sedimentological, geochemical and palaeontological evidence
Authors: Domack Eugene W. , Ishman Scott E. , Stein Andrew B. , McClennen Charles E. , Jull A.J. Timothy
Published: December 2007

Marine sediment cores were obtained from in front of the Müller Ice Shelf in Lallemand Fjord, Antarctic Peninsula in the austral summer of 1990–91. Sedimentological and geochemical data from these cores document a warm period that preceded the advance of the Müller Ice Shelf into Lallemand Fjord. The advance of the ice shelf is inferred from a reduction in the total organic carbon content and an increase in well-sorted, aeolian, sand in cores proximal to the present calving line. This sedimentological change is paralleled by a change in the foraminiferal assemblages within the cores. Advance of the ice shelf is indicated by a shift from assemblages dominated by calcareous benthic and planktonic forms to those dominated by agglutinated forms. A 14C chronology for the cores indicates that the advance of the Müller Ice Shelf took place c. 400 years ago, coincident with glacier advances in other high southern latitude sites during the onset of the Little Ice Age. Ice core evidence, however, documents this period as one of warmer temperatures for the Antarctic Peninsula. We suggest that the ice shelf advance was linked to the exclusion of circumpolar deep water from the fjord. This contributed to increased mass balance of the ice shelf system by preventing the rapid undermelt that is today associated with warm circumpolar deep water within the fjord. We also document the recent retreat of the calving line of the Müller Ice Shelf that is apparently in response to a recent (four decade long) warming trend along the western side of the Antarctic Peninsula.
Form, structure and stability of the margin of the Antarctic ice sheet, Vestfold Hills and Bunger Hills, East Antarctica
Authors: Fitzsimons Sean J. , Colhoun Eric A.
Published: December 2007

Studies of glacier margins have suggested that form and structure can be used to infer mass balance condition and stability. This paper examines this idea by investigating the form and structure of the Antarctic ice sheet at two coastal oases in East Anarctica. Two principal forms of the margin of the ice sheet in the Vestfold and Bunger hills that are discussed are ice cliffs and gently-sloping ice margins with an inner moraine. The form of the ice margins in both areas is primarily related to the accumulation of drift snow and superimposed ice and not to mass balance condition. It is concluded that the form and structure of ice margins are ambiguous indicators of mass balance condition and stability and that a change in mass budget is probably neither a sufficient nor a necessary condition for a change in the morphology of ice margins. Although we argue that the form and structure of the ice margins tells us little about stability, interpretation of the Holocene history and geomorphology of the oases suggests that the ice margins have been stable at least throughout the Holocene and that this condition of overall stability continues today.
New K-Ar isotopic ages of schists from Nordenskjöld Coast, Antarctic Peninsula: oldest part of the Trinity Peninsula Group?
Authors: Smellie J.L. , Millar I.L.
Published: December 2007

K-Ar whole-rock dating of five samples of quartz-mica schist from the Nordenskjöld Coast, eastern Graham Land, provides the first unequivocal evidence of pre-Triassic (> 249 ± 7 Ma) deposition of a sequence regarded as part of the Trinity Peninsula Group (TPG). A maximum age range of latest Carboniferous (< c. 300 Ma)–Permian for deposition of the Nordenskjöld Coast sequence is indicated, and a polymetamorphic, polydeformational history for the TPG in northern Graham Land. However, the possibility exists that the rocks dated here from the Nordenskjöld Coast are part of a hitherto-unrecognized metamorphic basement unrelated to and older than the mainly Triassic TPG outcrops farther north. The new ages confirm the existence of a previously poorly-defined regional metamorphic event in the Antarctic Peninsula at about 245–250 Ma ago.
Mapping ice front changes of Müller Ice Shelf, Antarctic Peninsula
Authors: Ward Caroline G.
Published: December 2007

Müller Ice Shelf (67°15′S, 66°52′W) is situated at the southern end of Lallemand Fjord. It is a small ice shelf (∼80 km2) fed by Brückner and Antevs glaciers, which both flow northward off the central peaks of Arrowsmith Peninsula; the ice shelf contains an ice rise (Humphreys Ice Rise). Data sources have indicated that not only has the ice front retreated since 1947 but also that there have been two advances. This paper describes how these changes were recorded using simple photogrammetric techniques.
Because it is there
Authors: Kapitsa A. , Heap J.
Published: December 2007

When an Englishman, George Leigh Mallory, was repeatedly asked in 1923, during a lecture tour in America, why he wanted to climb Mount Everest, he replied, simply “Because it is there”. In the course of a recent workshop on the phenomenon of Antarctic sub-glacial lakes, best exemplified by the largest known lake which lies under the Russian Vostok station, a similar question was hovering in the air. “Why drill through to the lake?”; one could sense the wish that it would be sufficient, simply to give the “Mallory” answer. Mallory's reply carries with it the feeling of a “put down,” as if he were saying that he wanted no more questions about his motives for engaging in a venture which needed no further justification. Similarly, many scientists would be tempted to answer with the same asperity. “Don't question our motives- this is an experiment. We will build hypotheses about what we are likely to find, and then test them by drilling through; but the ultimate justification lies in the fact that Lake Vostok, is there, and is a proper object of human enquiry”.
Early life history of the Patagonian toothfish, Dissostichus eleginoides Smitt, 1898 in the Atlantic sector of the Southern Ocean
Authors: Evseenko S.A. , Kock K.-H. , Nevinsky M.M.
Published: December 2007

Dissostichus eleginoides spawn over the continental slope from June to September. The eggs, 4.3–4.7 mm diameter, were found in the upper 500 m of the water column over waters 2200–4400 m deep. Incubation of eggs is likely to take about three months. Hatching is probably in October/November. Embryos in egg development stages III and IV are described. Scales are not present until the fish are about 64–74 mm long.
Sponges of the Lazarev and Weddell Sea, Antarctica: explanations for their patchy occurrence
Authors: Gutt Julian , Koltun Vladimir M.
Published: December 2007

Seventy-three sponge species were caught at 23 stations on the continental shelf of the Lazarev and Weddell Sea (Atlantic sector of the Southern Ocean). Tedania tantula was the most often found species amongst the 63 demosponge species caught and among the five hexactinellid species Rossella racovitzae was most common. The stations were classified according to their species inventory, and so the individual stations of the resulting four groups were rather uniformly dispersed over the entire investigation area. The species composition of adjacent stations varied considerably. There was no discernible relationship between the biological set of data and any combination of the available environmental characteristics of the stations. The sponge fauna of the, so far very poorly investigated, Lazarev Sea did not differ considerably from that of the adjacent Weddell Sea. The only species to be recorded for the first time on the Antarctic continental shelf were Homaxinella flagelliformis and Hyrtios arenosa. Small scale environmental events such as iceberg scouring, or biological characteristics such as extremely slow growth and budding reproduction are thought to generate the patchy distribution pattern.
Fecundity and reproductive habits in Patagonotothen tessellata (Richardson, 1845) from the Beagle Channel, Argentina
Authors: Rae G.A. , Calvo J.
Published: December 2007

Population fecundity and reproductive habits in Patagonotothen tessellata were established for each reproductive period during 1988 and 1989. Fecundity/total length and fecundity/total weight relationships were analysed through regression models. Fecundity was positively correlated with fish length and weight. Mean fecundity was 25932 eggs (range 7634–62033). The regressions for each reproductive period are similar, suggesting that the amount of energy allocated to reproduction does not vary between spawning periods. Parental behaviour is described from both field and laboratory observations. Nesting and parental care were carried out by P. tessellata males. The life history strategy of this species is discussed in relation to that of other nototheniid species.
Naming of igneous and metamorphic rock units in Antarctica: recommendation by the SCAR Working Group on Geology
Authors: Cox Simon C. , Allibone Andrew H.
Published: December 2007

Recently Ricci et al. (1993) proposed a series of general guidelines for the naming of igneous and metamorphic rocks in Antarctica, based on discussions held by the SCAR Working Group on Geology. Ricci et al. (1993) suggested that names for igneous and metamorphic rock units should comprise an appropriate geographic name and simple lithological field term. However, they also suggest that names should not include terms that indicate the form or structure of a rock unit, such as dyke, pluton or batholith.
An annual profile of growth in the otoliths of immature Notothenia coriiceps Richardson in relation to the environment at Signy Island, Antarctica
Authors: Ashford Julian R. , White Martin G.
Published: December 2007

Scanning electron microscope and image analysis techniques were used to construct a profile of otolith growth from June 1987–June 1988 in immature Notothenia coriiceps. Growth was found to fluctuate seasonally with a large decrease between August and late November 1987. Examination of stomach fullness showed that fish continued to feed during winter. Increases in absolute light levels and sea temperature during spring were found to coincide approximately with increasing growth. Conclusive evidence distinguishing between hypotheses for limitation of growth either by seawater temperature or by resource availability was not found.
Seasonal change in the distribution and density of seals in the pack ice off Princess Martha Coast, Antarctica
Authors: Bester Marthán N. , Erickson Albert W. , Ferguson J. Willem H.
Published: December 2007

During the period 9 December 1991–4 February 1992 shipboard and aerial surveys of seals in the pack ice off the Princess Martha Coast were made. All aerial surveys were flown from the MV SA Agulhas at the edge of the fast ice opposite SANAE at 70°19′S, 02°26′W. A total of 18 1/2-nm-wide transects were flown censusing 481.3 nm2 of pack ice within which 1437 seals were counted. The species composition of the seals was 94.4% crabeater, 3.4% Ross, 1.4% leopard and 0.8% Weddell seals. The density of seals nm−2 for the early season surveys (December) in the inner pack was 1.92 for crabeater, 0.0 for leopard; 0.026 for Weddell and 0.057 for Ross seals. The density for the late season surveys throughout the pack was 4.02 for crabeater, 0.10 for leopard, 0.029 for Weddell and 0.122 for Ross seals. These data support the thesis that seal densities increase as the amount of pack ice diminishes with the advance of summer. Leopard seals were largely found near the retreating outer edge of the pack, and Weddell seals associated closely with the inshore fast ice, whilst both crabeater and Ross seals showed no statistically significant preference either for any part of the pack ice or for any particular geographical area covered during the surveys in the present study. The high densities (0.45−2.91 seals nm−2) and percentage species contribution (9.7−32.4%) of Ross seals determined by shipboard censuses in the same area during the early 1970s could not be confirmed in the present study, and it is likely that a real decrease in Ross seal numbers has taken place.
Chromosome differentiation in the subantarctic Bovichtidae species Cottoperca gobio (Günther, 1861) and Pseudaphritis urvillii (Valenciennes, 1832) (Pisces, Perciformes)
Authors: Pisano Eva , Ozouf-Costaz C. , Hureau J-C. , Williams R.
Published: December 2007

A cytogenetic study on the bovichtid species Cottoperca gobio from the Magellan Strait and Pseudaphritis urvillii from Tasmania showed both species have a plesiomorphic number of chromosomes (2n=48). However, C.gobio has a more conservative karyotype composed entirely of acrocentric chromosomes (Fundamental Number=48); the presence of two metacentric pairs in P. urvilli (FN=52) makes this species karyologically more derived. The differences in the number of chromosomal arms, and the chromosomal location of the nucleolar organizer regions indicate karyological divergence in the two separating stocks from which C.gobio and P.urvillii originated. During the diversification of this notothenioid family, probably coincident with the fragmentation of Gondwana, the stock that split off with the Australian Plate gave rise to the Tasmanian species and experienced more chromosomal modifications than the stock from which C. gobio is derived. The pattern of constitutive heterochromatin suggests a possible homology between a pair of chromosomes in bovichtids and other notothenioids.
Seasonal abundance and size variation in Antarctic populations of the Cladoceran Daphniopsis studeri
Authors: Bayliss P.R. , Laybourn-Parry J.
Published: December 2007

Continental freshwater lakes of Antarctica are characterized by species-poor biota (Heywood 1977). The plankton is dominated by algae, bacteria and protozoa (Koob & Leister 1972, Parker et al. 1982, Laybourn-Parry et al. 1991). Three species of micro-crustacea have been reported from Eastern Antarctica, the cladoceron Daphniopsis studeri, Ruhe and two copepods, Acanthocyclops mirnyi, Borutsky & Vinogradov, and Boeckella poppei, Mrazek (Borutsky & Vinogradov 1957, Akatova 1964, Bayley & Burton 1993). The origin of D. studeri in lakes of the Vestfold Hills has been documented (Laybourn-Parry & Marchant 1992) and it is generally thought that populations are derived from subantarctic islands and mainland South America. Populations of D. studeri from three freshwater lakes of the Vestfold Hills, have been studied in more detail in a preliminary survey of its occurrence and basic life cycle (Laybourn-Parry & Marchant 1992) during which it was observed that the population consisted entirely of parthenogenic females appearing to produce only subitaneous eggs. Herbert (1981) reported that some Arctic and Antarctic cladocerans were capable of producing ephippial (wintering) eggs asexually. D. studeri also occurs in some of the brackish lakes of the Vestfold Hills with salinities of <4 ppt. These populations were found to possess male individuals (J. Gibson, personal communication 1991) suggesting a sexual cycle and production of resting eggs. There is no evidence of this in the freshwater lakes of the region.
A case study of turbulent parameters during the Antarctic winter
Authors: Yagüe Carlos , Redondo José M.
Published: December 2007

Two days of the Antarctic winter (20 and 21 June 1986) were chosen to study some turbulent parameters in this particular boundary-layer. Richardson number, Monin-Obukhov length, eddy transfer coefficients, turbulent kinetic energy, turbulent intensities, friction velocities and sensible heat flux at three levels (5, 17 and 32 m) were considered. The results show how the stability at 17 and 32 m influences the turbulent transfer at 5 m. The shear of wind is the main mechanism to produce mixing in the lower atmosphere at Antarctica, and thermal inversions associated to surface cooling develop with winds < 10 ms−1 at 5 m. The possible influence of internal gravity-waves on the atmospheric boundary-layer during strong stable stratification is studied.
Ozone – ideals and realities
Authors: Walton D W H
Published: December 2007

The public expects all Arctic scientists to know about polar bears, and all Antarctic scientists to be expert on the “ozone hole”. Exposure to bears or the effects of ozone depletion can result in death and are both thus newsworthy. Yet whilst deaths from bears continue to be news, some parts of the media appear to be showing “ozone fatigue” — the public are deemed to have heard enough of this story. Too bad — because the story can only get worse before it gets better.
Do Antarctic benthic invertebrates show an extended level of eurybathy?
Authors: Brey T. , Dahm C. , Gorny M. , Klages M. , Stiller M. , Arntz W.E.
Published: December 2007

Depth distribution data were compared for 172 European and 157 Antarctic benthic invertebrate species occurring in the respective shelf areas. Antarctic species showed significantly wider depth ranges in selected families of the groups Bivalvia, Gastropoda, Amphipoda and Decapoda. No differences were found in Polychaeta, Asteroidea and Ophiuroidea, where European species also showed comparatively wide bathymetric ranges. These extended levels of eurybathy in the Antarctic benthos may be interpreted either as an evolutionary adaptation or pre-adaptation to the oscillation of shelf ice extension during the Antarctic glacial-interglacial cycle.
Particulate organic matter composition in Terra Nova Bay (Ross Sea, Antarctica) during summer 1990
Authors: Fabiano M. , Povero P. , Danovaro R.
Published: December 2007

Particulate organic matter was collected in the coastal waters of Terra Nova Bay during the Oceanographic Campaign of the Italian Antarctic Research Programme in summer (January–February) 1990. Particulate matter composition was analysed for organic carbon and nitrogen, carbohydrates, proteins, lipids, nucleic acids (DNA and RNA) and ATP. A vertical stratification was evident in the study area, and resulted from prior melting of the pack ice. Suspended organic matter in the mixed layer and below the mixed layer differed in quantitative and qualitative composition. Except for ATP, all the biochemical components showed higher concentrations in the mixed layer than in the deeper waters. The particulate organic matter in Terra Nova Bay was mostly detrital and of algal origin.
Biogenic brominated and iodinated organic compounds in ponds on the McMurdo Ice Shelf, Antarctica
Authors: Schall Christian , Heumann Klaus Gustav , Mora Stephen De , Lee Peter A.
Published: December 2007

During January 1994 seven meltwater ponds on the McMurdo Ice Shelf were investigated for their content of biogenic iodinated and brominated volatile hydrocarbons. An efficient purge and trap system in combination with a powerful gas chromatographic separation and an electron capture detector achieved detection limits of 0.02–0.4 ng 1−1, depending on the different substances. The following compounds could be identified and quantified: CH3I, CH2I2, CH2C1I, CHBr3, CH2Br2, BrCH2CH2Br, CHBr2Cl, and CHBrCl2. This is the first time that 1,2–dibromoethane has been detected as a biogenic substance in the environment. In contrast to many other aquatic systems, where CH3I is found to be the most volatile iodine compound, CH2I2 showed the highest concentration in all ponds falling in the range of 5–20 ng 1−1. In three of seven ponds investigated, CH2CII was the second abundant iodinated substance. CHBr3 usually exhibited concentrations in the range of 2.5–8.6 ng 1−1. BrCH2CH2Br, previously not observed as a biogenic compound, was found to have concentrations similar to those of bromoform and even exceeded the bromoform content in two ponds and the CH2Br2 content in all ponds. Whether cyanobacteria, the dominant organisms in the ponds, are responsible for this distribution pattern must be clarified by further investigations.
Palaeomagnetic results from the middle Tertiary Meander Intrusives of northern Victoria Land, East Antarctica
Authors: Belluso Elena , Lanza Roberto
Published: December 2007

The Tertiary stocks (Meander Intrusives) cropping out along the coasts of the Ross Sea were sampled for a palaeomagnetic study during the sixth Italian expedition to northern Victoria Land. Laboratory investigations concerned magnetic mineralogy and remanent magnetization. Minerals of the magnetiteulvöspinel series occur in the rocks from all stocks, with low-Ti titanomagnetite usually prevalent. Haematite and goethite occur in small amounts as alteration products. Large secondary components commonly screen the characteristic remanent magnetization and were removed by thermal or AF demagnetization at temperatures or peak-fields higher than 360°C and 20 mT respectively. A total of 10 VGPs were obtained from radiometrically dated rocks (42–22 Ma); the averaged position (69°S, 334°E; α95=9.9°) is the first middle Tertiary palaeomagnetic pole for East Antarctica, and gives evidence for a reversal in the course of the APW path. This evidence is not substantially altered by a supposed tilt-correction consistent with geophysical and geological models for the uplift of the Transantarctic Mountains. No definite conclusion about relative movements between East Antarctica and the Antarctic Peninsula can be drawn from the existing palaeomagnetic data.
Longwave atmospheric radiation over Antarctica
Authors: King J.C.
Published: December 2007

The seasonal and spatial variation of downward longwave radiation (L↓) at the surface of the Antarctic ice sheet is studied using data from four stations. L↓ is found to depend on the fourth power of the surface temperature but on the sixth power of the temperature at the top of the surface inversion layer. The former result is shown to be a consequence of the dominance of longwave radiation in the surface energy balance while the latter raises some questions concerning the radiative properties of Antarctic clouds. Simple parametrizations of L↓ as a function of temperature are suggested; these may find application in validating General Circulation Model radiation calculations over Antarctica.
Biomass allocation in a subantarctic clonal plant (Acaena magellanica) under grazing by introduced reindeer
Authors: Moen Jon , Walton David W.H.
Published: December 2007

Biomass allocation and growth by the clonal plant Acaena magellanica were characterized for three populations grazed by introduced reindeer on the subantarctic island of South Georgia. Annual growth markers (internode lengths) were used to divide each rhizome into current year's shoots, one-year-old and two-year-old rhizome segments. Total dry weights were significantly smaller in grazed than in ungrazed populations. Leaf biomass of current year's shoots was very much lower in grazed shoots. Rhizome length and number of leaves were less affected than dry weight by grazing, and the reindeer grazing thus seems to mainly influence biomass accumulation rather than morphology in Acaena. Interactions with Festuca contracta in both grazed and ungrazed areas were also studied in a two-year competition experiment. No apparent release of soil resources (as measured by an increase in plant growth) was apparent in plots where Festuca was removed, but the current year's shoots of Acaena were smaller and more numerous in these plots than in controls, especially in the ungrazed area.
Six new species of Grania (Oligochaeta, Enchytraeidae) from the Ross Sea, Antarctica
Authors: Rota Emilia , Erséus Christer
Published: December 2007

Six new species of marine Enchytraeidae, Grania hirsuticauda sp.n., G. acanthochaeta sp.n., G. carchinii sp.n., G. angustinasus sp.n., G. antarctica sp.n. and G. algida sp.n., are described from benthic material collected in McMurdo Sound during 1959–61 and Terra Nova Bay in 1988. They represent the first records of this family from below the Antarctic circle and, together with tubificids, the first oligochaetes from the Ross Sea. G. hirsuticauda, apparently the most widespread species in McMurdo Sound, is distinguished by having setae abruptly larger in the posterior third of the body and almost nodulate; a T-shaped prostomial bifurcation of the dorsal vessel, short sperm funnels and sperm sac, and thick-walled spermathecae. G. acanthochaeta possesses a unique, thorn-like, setal morphology and diverticulate spermathecal ampullae. G. carchinii, the only new species lacking lateral setae, is also distinguished by a remarkably high development of the chloragogen tissue and the possession of nephridia at 6/7. G. angustinasus, the most abundant species in the sampling area in Terra Nova Bay, and G. antarctica, have the same setal distribution, size and (curved) shape, but show different forms of penial bulbs (more complex in G. angustinasus) and spermathecal structures (the ampullae being larger and the external pores more posterior in G. antarctica). G. algida is distinguished by its L-shaped setae and carrot-shaped, diverticulate, spermathecal ampullae. All the new species lack cuticular penial stylets as well as spermathecal ectal glands. All species but G. carchinii are peculiar in possessing, in front of the brain, a middorsal vesicular body of specific shape and size containing a few refractile inclusions; a sensory (possibly a statocyst-like) function is suggested for this ‘head organ’, which has not been previously reported in the Oligochaeta.
Status of southern elephant seals at South Georgia
Authors: Boyd I.L. , Walker T.R. , Poncet J.
Published: December 2007

Approximately 54% of the world population of southern elephant seals (Mirounga leonina) breeds at South Georgia. A partial survey in 1951 and a complete survey in 1985, together with counts at specific sites between these times, suggested that the population (around 100 000 breeding females) had not changed significantly in 34 years. This was in contrast to marked declines in most other populations. To examine this further, we conducted a third survey in 1995. This produced an estimate of 113 444 (se = 4902) breeding females. Taking into account improved information about the behaviour of female elephant seals since the survey in 1985, there was no significant change in the number of breeding female elephant seals between 1985 and 1995. When combined with information from the 1951 survey, this supports the view that the total population size has not changed significantly during the past 45 years. Evidence for regulation of the population by environmental factors is equivocal. We hypothesize that the lack of any net change in population size may be linked to a limited availability of high quality breeding habitat.
Tissue distribution of organochlorine residues – PCBs and pesticides – in Antarctic penguins
Authors: Inomata Odete N.K. , Montone R.C. , Lara W.H. , Weber R.R. , Toledo H.H.B.
Published: December 2007

Antarctic penguins constitute excellent indicators of organic pollutants (PCBs, DDTs and HCHs), which reach the Antarctic either by atmospheric or maritime transport and are concentrated through the food chains. They are found mainly in lipids, both in adipose and other tissues of the organisms. Tissue samples of four gentoo and one Adélie penguins were collected during the summers of 1991, 1992 and 1993. PCBs and organochlorine pesticides (OCPs) were analysed in the adipose tissue, uropygeal gland, blood, brain, muscle, bone and liver. Organochlorines (OCs) were detected in the majority of the samples. The levels found in extractable fat were higher than in other tissues and the concentrations ranged from 42.3–1159.7 ng g−1 (HCB), from not detected to 39.3 ng g−1 (HCHs), from 30.8–972.3 ng g−1 (DDTs) and from 43.2–1583.6 ng g−1 (PCBs).
The life cycle strategy of the ice-associated copepod, Paralabidocera antarctica (Calanoida, Copepoda), at Syowa Station, Antarctica
Authors: Tanimura Atsushi , Hoshiai Takao , Fukuchi Mistuo
Published: December 2007

The vertical distribution, abundance, population structure and life cycle of the ice-associated copepod, Paralabidocera antarctica was studied in the fast ice near Syowa Station (69°00'S, 39°35'E) in the eastern part of Lützow-Holm Bay in 1970, 1975 and 1982. The results indicated that P. antarctica inhabited the ice-seawater interface throughout the year with a one year life cycle and was actually present in the sea ice for most of the year except the summer. P. antarctica overwintered as naupliar stages (NIV-NV) with slow development in sea ice during winter. P. antarctica population then developed rapidly and attained adulthood in the water just beneath the sea ice during spring-summer. P. antarctica depended entirely on ice algae for food throughout its whole life-span, suggesting that the ice-seawater interface provides favourable food conditions for P. antarctica. The slow development in naupliar stages in sea ice and short copepodite life span in the water suggest that P. antarctica may adapt its growth strategy to suit the varying fast ice/water interface environment.
On the relationship between extra-terrestrial radiation and surface pressure
Authors: Wendler Gerd , Pook Michael
Published: December 2007

The surface pressure of an Antarctic station displays two minima, one in spring, the other in autumn. It is believed that these minima are caused by radiative forcing, as the gradient of the extra-terrestrial radiation is largest during the two equinoxes. The best correlation (r = 0.85) was obtained when the pressure lagged the radiation gradient by ten days.
Making money from Antarctica
Authors: Walton D W H
Published: December 2007

The Antarctic is no stranger to the economic opportunist. The history of whaling, sealing and now fishing shows that no place is too remote to deter industry exploiting the resources to meet a perceived market need. But all this has changed hasn't it? Antarctica today is a pristine wilderness ‘devoted to peace and science’ as it says in the Protocol. Maybe, but the climate in Antarctica is changing in ways other than meteorological so perhaps we should look more closely see what changes are brewing.
Holocene environmental change in a marine-estuarine-lacustrine sediment sequence, King George Island, South Shetland Islands
Authors: Martinez-Macchiavello J.C. , Tatur A. , Servant-Vildary S. , Del Valle R.
Published: December 2007

Sedimentological features and cluster analysis of diatom assemblages were used to investigate a local Holocene prograding sequence of marine-estuarine-lacustrine sediments. It consists of upward finning and thinning sediment cycles formed at the mouth of a meltwater stream during regional isostatic uplift, which followed early Holocene deglaciation and marine inundation events. The sequence begins in the lower Holocene sublittoral sand (marine diatoms and abundant molluscs) overlying, with a transgressive base, the deltic (?) clastic sediment marking probably one of the pre-Holocene interglacial periods (index diatom Actinocyclus ingens suggests an age >0.62 Ma). The lower Holocene marine sand was truncated by middle Holocene gravity flows, bearing volcanic ash. They were deposited in a high energy estuarine environment (brackish diatoms). The beach subsequently formed separated the estuary from the sea and changed it into a freshwater lake. Accumulation of moss and gyttja, containing a freshwater diatom assemblage, marks the final late Holocene stage of this coastal sedimentary sequence, which can be considered as typical for deglaciation periods in the maritime Antarctic.
Antarctic krill under perennial sea ice in the western Weddell Sea
Authors: Melnikov Igor A. , Spiridonov Vassily A.
Published: December 2007

The results of underwater observations and sampling of krill (Euphausia superba) in the western Weddell Sea during the joint Russian-USA Ice Station Weddell-1 Expedition (11 February–9 June 1992) are presented. Krill was sampled from the same large ice floe composed of both 1- and 2-year ice as it drifted northward for a distance of c. 700 km. Abundance estimates for krill under this floe were in the range 0.1–6.25 ind m−2. Krill aggregate in areas where rafting of ice floes and formation of new ice occur, or around a protected diving hole. The krill sampled consisted mainly of furcilia 6 and post-larvae which did not belong to the 0+ group originating in this (1991–92) year, but presumably hatched in the summer season of 1990–91 and developed very slowly so that at the end of the following summer season, larval stages were still present in the population. No increase of the mean krill size was observed during 2.5 months of observation. The role of larval advection for the maintenance of krill population in the Weddell Sea is discussed.
The geology of Cape Dubouzet, northern Antarctic Peninsula: continental basement to the Trinity Peninsula Group?
Authors: Hervé Francisco , Lobato Jorge , Ugalde Ignacio , Pankhurst Robert J.
Published: December 2007

Cape Dubouzet is mainly composed of a volcanic-subvolcanic complex of extrusive rhyolitic breccias, a banded rhyolite and a semi-annular body of dacite porphyry rich in xenoliths of metamorphic rocks. Major and REE geochemistry indicate that the volcanic rocks are calc-alkaline and that they are genetically related by fractional crystallization of a plagioclase-bearing assemblage from a common magma. Rb-Sr data suggest that the rhyolitic complex is of Middle-to-Late Jurassic age, and that it is intruded by Late Cretaceous stocks of banded diorite and gabbro. All these rocks are partially covered by moraines whose clasts are of local provenance. Xenoliths in the dacite porphyry suggest that the northern tip of the Antarctic Peninsula is underlain by a metamorphic complex composed of amphibolites, meta-tonalites and pelitic gneiss containing garnet, sillimanite, cordierite, hercynite, and andalucite. Such rocks are not known in the Scotia metamorphic complex, nor in the Trinity Peninsula Group and its low grade metamorphic derivatives, which also occur as rare xenoliths in the dacite. Previous dating of xenoliths collected from the moraines suggested a late Carboniferous age for this amphibolite-grade metamorphism. Both the Jurassic-Cenozoic magmatic arc of the Antarctic Peninsula and the accretionary complex rocks of the Trinity Peninsula Group were thus developed, at least in part, over pre-existing continental crust.
The terrestrial arthropod fauna and its habitats in northern Marguerite Bay and Alexander Island, maritime Antarctic
Authors: Convey Peter , Smith Ronald I. Lewis
Published: December 2007

Field surveys of free-living terrestrial microarthropods were made during the 1994–95 summer at four sites in northern Marguerite Bay (Anchorage Island, Lagoon Island, Léonie Island, Rothera Point; c. 68°S, 68°W) and three on southern Alexander Island (Two Step Cliffs, Fossil Bluff, Ablation Valley; c. 71–72°S, 68°W). Detailed site descriptions are presented, as little previous information exists. Twenty species (four Collembola, 16 Acari) were recorded from the Marguerite Bay sites, with a maximum of 17 species at one site. A further four species (one Collembola, two Acari, one Diptera) have been recorded from the same area by other authors. Species diversity at these sites, in particular Léonie Island, is as great as at any known site elsewhere in the maritime Antarctic, although the total area of terrestrial habitat available is small. Individual species and total population densities are also similar to, if not greater than, published studies from the South Shetland and South Orkney Islands. None of the species is new to the maritime Antarctic, although the distributions of several are extended southwards. Only nine species (maximum seven at one site) were found on Alexander Island, concurrent with decreases in population densities to levels similar to those found in many continental Antarctic studies. This still represents a high species diversity for such a high latitude site. The richness of two sites, Ablation Valley and Mars Oasis (Two Step Cliffs), is unlikely to be repeated elsewhere on Alexander Island. The Alexander Island fauna is clearly related to that of the maritime Antarctic, as all except one species occur at more northerly sites elsewhere on the Antarctic Peninsula, and none in the continental Antarctic. One species, Friesia topo (Collembola), is known only from Alexander Island.
Evidence for physical and chemical stratification in Lake Untersee (central Dronning Maud Land, East Antarctica)
Authors: Wand U. , Schwarz G. , Brüggemann E. , Bräuer K.
Published: December 2007

Lake Untersee is the largest freshwater lake in the interior of East Antarctica. It is a perennially ice-covered, max. 169 m deep, ultra-oligotrophic lake. In contrast to earlier studies, we found clear evidence for physical and chemical stratification in the summer of 1991–92. However, the stratification was restricted to a trough, c. 500 m wide and up to 105 m deep, in the south-western part of the lake. There, the water body was distinctly stratified as indicated by sharp vertical gradients of temperature, pH, dissolved oxygen, and electrical conductivity. The water column was anoxic below 80 m. The chemical stratification is also indicated by changes of ionic ratios. Moreover, there was some evidence for methanogenesis and bacterial sulphate reduction in Lake Untersee.
Methanesulphonate and non-sea salt sulphate in aerosol, snow, and ice on the East Antarctic plateau
Authors: de Mora S.J. , Wylie D.J. , Dick A.L.
Published: December 2007

This investigation reports the first simultaneous measurement of methanesulphonate (MSA) and non-sea salt sulphate (NSSS) in aerosols, surface snow, and ice core samples for a continental site in Antarctica (78°S, 139°E, elevation 2849 m). Aerosol MSA concentrations ranged from 0.09–0.43 nmol m−3 STP (median 0.14 nmol m−3) and were generally lower than those observed at coastal Antarctic sites. NSSS concentrations varied from 0.66–1.32 nmol m−3 stp (median 0.88 nmol m−3), comparable to those reported for other continental Antarctic locations. Whereas the MSA:NSSS molar ratio in aerosol samples was in the range 12.7–32.5% (median 17.0%), the ratio down a snow pit and ice profile varied from 1.14–55.6% (median 3.50%), reflecting the variability to be expected over a period of a decade. The chemical composition and low MSA content suggests an origin of aerosols consistent with long range transport from mid-latitudes.