bluuebunny/crossref_metadata_2025 huggingface dataset:
A diel study of the neuston and plankton bacteria in an Antarctic pond
Authors: Maki J.S. , Herwig R.P.
Published: December 2007

A small freshwater pond near Palmer Station, Anvers Island, (64° 45'S, 64° 05'W) was sampled every 6 h over a 24 h period during the late austral summer to examine changes in both neuston and plankton population levels and activity. Total bacteria using acridine orange and epifluorescence microscopy, counts of viable colony-forming units, and chlorophyll a were determined. Activity was estimated by measuring the rate of 3H-thymidine incorporation. The data indicate that over this time period the bacterioneuston populations went through a diel fluctuation and temperature may be an important factor in this cycle. Although the bacterioneuston populations were often more numerous than corresponding plankton populations, subsurface bacteria appeared to be metabolically more active.
The cryptostigmatid mite Halozetes belgicae (Michael) in the maritime Antarctic
Authors: Minto L.B. , Shepherd G.J. , Usher M.B.
Published: December 2007

Halozetes belgicae is distributed widely in the Subantarctic and maritime Antarctic, with subspecies described from Macquarie Island and the South Sandwich Islands. A morphometrical study, based largely on the development of the setae, indicates that the nominate subspecies is confined to the Antarctic Peninsula and its offshore islands (including the South Shetland Islands), whilst specimens from the South Orkney Islands are probably consubspecific with individuals on the South Sandwich Islands. In comparison with other studies of the Acari, the results strengthen the case for the recognition of a South Orkadian biogeographical zone.
A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications
Authors: Björck Svante , Håkansson Hannelore , Zale Rolf , Karlén Wibjörn , Jönsson Bodil Liedberg
Published: December 2007

Analysis of a 1.5 m thick sediment sequence from Midge Lake, Byers Peninsula, Livingston Island, shows that the lake and its catchment have undergone significant changes during the last 4000 years. Radiocarbon dating (AMS), sediment lithology, and microfossil analyses indicate that the lake was deglaciated over 4000 14C years ago. Distinct peaks in accumulation rates of sediment, Pediastrum algae, pollen and spores, as well as changes in the diatom assemblage, suggest significant environmental changes between ca 3200 and 2700 y BP. These changes are interpreted as reflecting a milder and more humid, maritime climate. The increased humidity can explain independent observations of glacier growth during this period. The combined data also indicate that between ca 1500 and 500 y BP the area might have experienced more continental conditions with slightly colder and drier climate than today. Since the 14C dates from the Midge Lake sediments are regarded as reliable and the sediment sequence is rich in tephra layers this sediment sequence will be critical for a forthcoming tephra chronology of the region.
Aqueous geochemistry of major constituents in the Alph River and tributaries in Walcott Bay, Victoria Land, Antarctica
Authors: De Mora S.J. , Whitehead R.F. , Gregory M.
Published: December 2007

Two geochemical surveys of the major constituents of the Alph River, situated in Walcott Bay, Victoria Land, were undertaken in the austral summer of 1987–88. At the same time, tributaries and the runoff from various glaciers were investigated. The Alph River has an average total dissolved solids (TDS) concentration of 63.5 mgl−1, approximately half that of average world river water. The chemical composition is dominated by Na+ and HCO−3. Glacial melt waters have very low TDS but chemical weathering over the course of a few kilometres causes solute concentrations in the tributaries to exceed those of the Alph River. The composition of the streams is variable, but often Ca2+ is the principal cation. Enrichment factor and mass balance calculations indicate that the salts in the Alph River and its tributaries have a substantial non-marine component. Chemical weathering of calcite, mirabilite, gypsum and halite contribute solutes to the aquatic system. A “Gibbs Plot” [TDS versus Na:(Na+Ca) weight ratio] indicates that water samples from direct glacial runoff fall outside the world water envelope. They have low solute levels but enhanced Ca2+ concentrations, resulting from the aeolian deposition and subsequent dissolution of calcitic material.
Late Eocene gadiform (Teleostei) skull from Seymour Island, Antarctic Peninsula
Authors: Eastman Joseph T. , Grande Lance
Published: December 2007

On the basis of a skull from the late Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula, a gadiform fish is reported from the Antarctic region for the first time. This specimen, the most completely preserved fossil teleost cranium yet described from Antarctica, provides convincing evidence for the presence of Gadiformes in a far southerly location under temperate climatic conditions 40 m.y. ago. The exoccipital condyles, supraoccipital and lambdoidal crests, and post-temporal and supratemporal fossae are well preserved, as are the roofing bones on the posterior half of the skull. Comparative osteological study indicates that these features are very similar in appearance to those of merlucciids (hakes) and gadids (cods).
Reproduction in Antarctic notothenioid fish
Authors: Kock Karl-Hermann , Kellermann Adolf
Published: December 2007

Gonad maturation in Antarctic notothenioid fish is a biennial process although spawning is likely to take place annually. However, part of the populations of Champsocephalus gunnari in the Atlantic Ocean sector do not spawn each year. Gonadosomatic index (GSI) of females is 15–40% at spawning. Apart from a few nototheniid species of the GSI of males is much less and typically only 15–20% of that of females. Length at first spawning may be from 55% of Lmax onwards, but in many species it is not attained until 70–80% of the maximum length. The only exception is Champsocephalus gunnari at South Georgia which may begin spawning at about 40% of Lmax. Most species of the Seasonal Pack-ice Zone are autumn/winter spawners, whereas in the High-Antarctic Zone more species spawn in summer and autumn. Spawning time is remarkably constant among populations of some species, in others a latitudinal shift in spawning time is apparent. Fecundity is commonly positively correlated with fish length and weight. It exceeds 100 000 eggs only in a few nototheniid species and is commonly in the order of 1000 to 15–20 000 eggs. Ova diameter varies from 0.8 to 5.0 mm. Egg size distribution among fishes of the Seasonal Pack-ice Zone is bimodal. There is a general trend in nototheniids of increasing egg size and decreasing relative fecundity towards higher latitudes. Incubation time may be up to five months. Eggs of most species are probably left unattended for the long incubation period. Nest guarding has been observed in three species but may be more common in particular among the artedidraconids. A number of reproductive strategies associated with nest guarding, egg size and the duration of the pelagic phase have been identified.
Unprotected larval development in the Antarctic scallop Adamussium colbecki (Mollusca: Bivalvia: Pectinidae)
Authors: Berkman Paul Arthur , Waller Thomas R. , Alexander Stephen P.
Published: December 2007

Most Antarctic bivalves are small and protect their young by holding fertilized eggs or larvae in their mantle cavities for varying periods. Nourishment for these early growth stages is provided by yolk reserves rather than by planktotrophy. The anomalously large Antarctic scallop, Adamussium colbecki, has unprotected planktotrophic larvae that are spawned during the austral spring. Successful recruitment of these larvae, in populations which are most abundant in oligotrophic habitats, may be associated with episodic pulses of organic material. Reasons why planktotrophy persists in A. colbecki are suggested by a comparison with another large Antarctic bivalve, Laternula elliptica. The latter has protected lecithotrophic larvae that are released at the beginning of the austral winter. This comparison suggests that unprotected larval development persists in A. colbecki because of unusual anatomical and ecological adaptations among the adults of the Adamussium lineage that have been evolving in the Southern Ocean since the early Oligocene.
A new Epimeria (Crustacea, Amphipoda, Paramphithoidae) from the Weddell Sea
Authors: De Broyer Claude , Klages Michael
Published: December 2007

Epimeria rubrieques sp. n., belonging to the cold water family Paramphithoidae, occurred relatively often in Agassiz and bottom trawls taken during several German Antarctic Expeditions into the eastern Weddell Sea since 1983. Although this species is very conspicuous because of its long mid-dorsal teeth, bright pink-red colour and large size (up to 70 mm), it has only been recorded in the Weddell Sea. The new species is compared to its closest relatives Epimeria macrodonta and E. similis, and an updated key to the 14 species of Antarctic Epimeria is provided. Observations on the general and feeding behaviour of living specimens of Epimeria rubrieques sp. n. in aquaria showed the species to be an ambush predator and a weakly motile epibenthic walker, which swims only rarely.
Distribution and abundance of euphausiid larvae in the Prydz Bay region, Antarctica
Authors: Hosie G.W.
Published: December 2007

In January 1985 a net sampling survey was carried out on the distribution and abundance of euphausiid larvae in the Prydz Bay region. Euphausia superba occurred in low abundance, probably due to sampling preceding the main spawning period. Thysanoessa macrura occurred throughout the study area in consistently high abundance. Euphausia crystallorophias was marginally more abundant within its restricted range. Distinct north-south variations in larval age and developmental stages of T. macrura were observed indicating regional differences in spawning. Euphausia frigida was mainly confined to the upper 200 m of the Antarctic Circumpolar Current. E. superba larvae produced north of the shelf break, between 70°–83°E, moved north-east into the Antarctic Circumpolar Current. Larvae originating on the shelf moved rapidly west in the East Wind drift. E. crystallorophias had the same westward dispersion, but some larvae appeared to return eastward via the Prydz Bay Gyre and remain in the region. The data indicate that most E. superba larvae, providing they survive injuries cold temperature an food deprivation, will leave the area, suggests that Prydz Bay krill may not be a self maintaining stock.
Habitat selection by marine mammals in the marginal ice zone
Authors: Ribic C.A. , Ainley D.G. , Fraser W.R.
Published: December 2007

As part of the multi-disciplinary project, Antarctic Marine Ecosystem Research at the Ice Edge Zone (AMERIEZ), habitat selection by marine mammals was investigated within the marginal ice zone in relation to measured ice variables and other environmental factors. Data were collected on three cruises to the southern Scotia and northern Weddell seas during spring 1983, autumn 1986, and winter 1988. During winter, Antarctic fur seals were significantly associated with drift, pancake, brash ice, icebergs, and areas of uneven floe distribution, all characteristic of the marginal ice zone. Fur seals were seen in open water close to the ice edge during autumn, but during spring, as the pack ice began to retreat rapidly, animals were seen more often away from the ice. Minke whales were also associated with pancake and new ice but were seen further into the pack ice during both winter and autumn. The largest groups of minke whales during winter were observed with a large krill swarm in new ice. Crabeater seal was exclusively a species of the deep pack ice during all seasons and was associated with ice cover of 7–8 oktas and evenly distributed ice floes.
The age, petrogenesis and emplacement of the Dalmatian Granite, H.U. Sverdrupfjella, Dronning Maud Land, Antarctica
Authors: Grantham G.H. , Moyes A.B. , Hunter D.R.
Published: December 2007

The ∼470 Ma Dalmatian Granite forms sheet-like bodies intruded discordantly into orthogneisses, paragneisses and calcareous rocks belonging to the ∼1000 Ma Jutulrora, Sveabreen and Fuglefjellet formations respectively. The Dalmatian Granite is muscovite + biotite bearing. Two varieties are recognized, one that is magnetite-bearing and another that is characterized by tourmaline nodules. At some localities, development of the tourmaline-bearing variety is spatially associated with the presence of carbonates. Physical conditions of emplacement for the Dalmatian Granite are estimated to be approximately 700°C and 6kbar with pH2O = Pload. The emplacement of the granite is considered to have occurred syntectonically during D3 approximately 470 Ma ago. The granites are therefore similar in age to Pan African age granites in Mozambique as well as Ross Orogeny age granites in the Transantarctic Mountains.
U-Pb zircon dating of Proterozoic igneous charnockites from the Mawson Coast, East Antarctica
Authors: Young David N. , Black Lance P.
Published: December 2007

We report ion-microprobe U-Pb zircon ages from charnockites of a large Proterozoic composite batholith, Mawson Coast, Australian Antarctic Territory. The charnockites crystallized from orogenic magmas of intermediate composition (mainly 54–68% SiO2) intruded into a granulite-facies metasedimentary gneiss sequence between the second and third recognized deformations. A sample of low-Ti charnockite provides an age of 954 ± 12 Ma and a high-Ti charnockite is dated at 985 ± 29 Ma (all ages quoted at 95% confidence). The age difference is not significant at the 95% confidence level. Both these ages were obtained from zircons with igneous zoning and/or morphology and thus are thought to date igneous crystallization. Zircons from a felsic gneiss xenolith within the charnockite have cores of various ages, many from 1.7 to 2.0 Ga, but with other grains between 1.0 and 1.5 Ga and a single 2.5 Ga zircon. These zircon cores are direct evidence for an early to middle Proterozoic age for the supracrustal basement sequence in this mobile belt. Many of these zircon cores are concordant but abundant discordant grains suggest a complex history of multiple Pb-loss events. Zircon rims grew at 921 ± 19 Ma, probably during the post-charnockite deformation (D3). Previously obtained Rb-Sr dates for charnockite of 886 ± 48 Ma and 910 ± 18 Ma were probably also rest during D3. A Rb-Sr isochron date of 1061 ± 36 Ma previously reported for high-Ti charnockite from Mawson Rock is thought to be erroneous, and a new date of 959 ± 58 Ma (consistent with both the igneous and reset dates above) is interpreted from those data.
Antarctic politics and science are coming into conflict
Authors: Laws Richard
Published: December 2007

The current political regime for the Antarctic stemmed from the activities of the non-governmental International Council of Scientific Unions (ICSU) in planning and implementing the IGY (1957–58); subsequently the Antarctic Treaty came into force in 1961. The Treaty promotes freedom of scientific research and international co-operation and in the first two decades of its existence this was an undisputed priority. SCAR, a committee of ICSU, is a non-political organization, which initiates, promotes and co-ordinates scientific research in the Antarctic. SCAR has always attached the highest importance to environmental protection and for over thirty years has readily accepted an advisory role in relation to the Treaty System. One Convention (CCAS on seals) has a built-in advisory role for SCAR - an unusual, probably unique function for an NGO. Another (CCAMLR on marine resources) often seeks advice from SCAR. The success of the Antarctic Treaty System owes much to SCAR.
Hydrocarbons in the Antarctic marine environment
Authors: Cripps G.C. , Priddle J.
Published: December 2007

The Antarctic marine ecosystem contains low concentrations of a range of hydrocarbons, overwhelmingly biogenic in origin. The low natural levels of hydrocarbons and the small amount of local human activity make the Antarctic marine ecosystem suitable as a yardstick against which future global pollution by hydrocarbons can be assessed. At present, contamination is very low and difficult to resolve against the background. Local pollution is restricted to a very few events. A systematic programme with a clear definition of the natural background is proposed to monitor both global and local pollution.
The spatial distribution of microalgae on Antarctic fellfield soils
Authors: Davey M.C. , Clarke K.J.
Published: December 2007

The horizontal and vertical distributions of cyanobacteria and algae on soil polygons on Signy Island were investigated. Soil chlorophyll concentrations increased from the centre to the edge of the polygons. Similar distributions of the non-motile genera, such as Pseudanabaena and Nostoc, were observed, whereas the motile taxa, Phormidium and Pinnularia, were evenly distributed across the polygon. Phormidium autumnale was the most widespread taxon, and other Oscillatoriaceae were also important, although large differences in community composition between polygons were observed. Most of the algal biomass was concentrated near the surface of the soil, although chlorophyll degradation products were found to depths of up to 8 cm. Examination of the soil profile by fluorescence microscopy indicated that a large proportion of the microflora occurred in the zone 0–1 mm below the surface, and scanning electron microscopy confirmed that few algae occurred on the soil surface. It is suggested that this may be a desiccation-avoidance strategy. Vertical migration of the motile microalgae to the soil surface was not observed in the field, but could be induced in the laboratory in the presence of excess water, although no diel cycle to this movement was observed.
Freshwater stream ecosystems of James Ross Island, Antarctica
Authors: Hawes Ian , Brazier Paul
Published: December 2007

The freshwater streams of James Ross Island share many of the features common to other Antarctic streams. There is a diel variation in temperature and discharge, which follows the daily insolation cycle; catchments are barren; stream vegetation is predominantly algal, comprising mat-forming cyanobacteria and filamentous chlorophytes; and physical factors, particularly turbidity and bed stability are important in determining biomass and composition of algal assemblages. Nutrient concentrations vary from stream to stream and over a diel cycle, with minimum dissolved N in late afternoon. Biomass attained and photosynthetic and respiratory rates are also comparable to those recorded in other Antarctic streams, with low productivity/biomass ratios in perennial assemblages.
Ecological and physiological investigations in continental Antarctic cryptogams II. Moisture relations and photosynthesis of lichens near Casey Station, Wilkes Land
Authors: Kappen L. , Breuer M.
Published: December 2007

In the second of three field studies on the ecology and physiology of lichens on Clark Peninsula, Wilkes Land, Antarctica, photosynthetic activity due to natural and artificial soaking of lichen thalli was investigated. Gravimetric measurements were used to quantify water uptake by lichens in contact with snow or ice. Quantum flux density under a 15 cm thick layer of snow can reach light saturation for net photosynthesis of Usnea sphacelata at temperatures around 0°C. Measurements with a steady-state CO2 diffusion porometer in the field reveal that, in Usnea antarctica, Umbilicaria decussata, and U. aprina, the optimum water content for net photosynthesis was 75–115 % d.wt. after the thalli were sprayed with water or submerged. The depression of net photosynthesis at super-optimal water content was strong in these species. In naturally soaked Usnea sphacelata this depression was less apparent. The water content resulting from contact with snow is frequently near the optimum for photosynthesis. In lichens of continental Antarctica it seems that super-optimal water contents are the exception rather than the rule.
Distribution and abundance of post-larval krill (Euphausia superba Dana) near Prydz Bay in summer with reference to environmental conditions
Authors: Miquel Juan Carlos
Published: December 2007

Data on the distribution, abundance and population structure of krill in the Prydz Bay area during January–February 1985 are considered in relation to hydrography and phytoplankton standing stocks. Stratified mean density and biomass estimated for the whole surveyed area from RMT-8 hauls were among the lowest recorded (3.3 individuals 1000 m−3 and 3.1 g 1000 m−3) confirming Prydz Bay as a low krill abundance area in the Southern Ocean. Age cohorts 1+ to 4+ were present, the size of the animals increased from south to north and juveniles were mostly found in surface waters near the pack-ice. Adults were in an active reproductive phase: 98% of the females were mated and 35% were ready to spawn whereas 86% of the males carried spermatophores. Breeding was taking place in oceanic waters over deep zones with the spawning season limited to January-April. Phytoplankton biomass was also very low in the area (mean of 29 mg Chl a m−2 in the upper 200 m) and currents speed low, never reaching 10 cm s−1. Krill distribution was strongly related to water circulation pattern but not related to phytoplankton distribution.
Petrological and geochemical constraints on the genesis of Mesozoic–Cenozoic magmatism of King George Island, South Shetland Islands, Antarctica
Authors: Birkenmajer K. , Francalanci L. , Peccerillo A.
Published: December 2007

Petrological and geochemical data are reported for a series of Late Cretaceous-Middle Miocene volcanic, hypabyssal and intrusive rocks from King George Island (KGI) and from nearby Ridley Island, South Shetland Islands. Major element data indicate a calc-alkaline, basic to intermediate composition for the analysed samples. Although emplaced on a continental margin, the KGI rocks generally display low abundances of incompatible trace elements, close to those typically observed in calc-alkaline suites erupted in intraoceanic island arcs. A few samples have a significant negative Ce anomaly. Many incompatible elements define smooth positive trends on interelemental variation diagrams which suggests that magmas erupted at different times on KGI maintained a rather constant composition in terms of incompatible element ratios. Geochemical modelling, based on Sr isotope ratios and incompatible element ratios, suggests that the primary calc-alkaline magmas of KGI were all generated in an upper mantle modified by addition of small amounts of pelagic sediments dragged down by subduction processes.
First articulated teleost fish from the Paleogene of West Antarctica
Authors: Jerzmańska Anna
Published: December 2007

Marambionella andreae gen. et sp. nov. from the La Meseta Formation (Upper Eocene–?Lower Oligocene) on Seymour Island is the first fossil clupeid found in Antarctica and the first articulated teleost from the Antarctic Paleogene. It shows a mosaic of similarities and differences compared with various clupeid genera. This and the uncertainty about the polarity of characters within clupeids do not allow precise assessment of the phylogenetic relationships of Marambionella.
Interpretation of geomagnetic anomalies in Dronning Maud Land, East Antarctica
Authors: Wagner Steffen , Lindner H.
Published: December 2007

The geomagnetic field pattern in the vicinity of Georg Forster station, Antarctica, is discussed. Induced magnetization is assumed to model the regional minimum in the total field intensity (MAGSAT) located here, and an associated anomalous body at a depth of 50 km is calculated and interpreted. This model is, however, discounted in favour of a cross section derived from a meridional ground magnetic profile recorded over a distance of about 200 km. The most striking features of the profile are positive anomalies over the ice shelf which are explained by dykes of basic rocks emanating from the lower crust and from the mantle. The derived crustal structure reflects a transition from continental crust to transitional type crust.
Chimaeroid fish remains from Seymour Island, Antarctic Peninsula
Authors: Ward David J. , Grande Lance
Published: December 2007

Ischyodus dolloi Leriche 1902, the youngest record of the species, and Chimaera seymourensis sp. nov. are described from the La Meseta Formation, Late Eocene of Seymour Island, Antarctic Peninsula.
An ornithopod dinosaur from the Late Cretaceous of West Antarctica
Authors: Hooker J.J. , Milner A.C. , Sequeira S.E.K.
Published: December 2007

In February 1989, the partial skeleton of an ornithopod dinosaur was discovered during a British Antarctic Survey (BAS) expedition, supported by RRS John Biscoe, to the James Ross Island area, east of the Antarctic Peninsula. This was only the second dinosaur to be found in the continent of Antarctica, the first being an ankylosaur collected three years earlier (Olivero et al. 1986, Gasparini et al. 1987, Gasparini 1988, Gasparini & Olivero 1989, Olivero et al. 1991).
Classification of Antarctic surfaces using AVHRR data: a multispectral approach
Authors: Zibordi Giuseppe , Meloni G. Paolo
Published: December 2007

The mapping of sea, landice, sea ice and clouds, from Advanced Very High Resolution Radiometer (AVHRR) images taken over Antarctica in daylight is investigated and a classification scheme is proposed on the basis of thresholds retrieved from multispectral patterns of representative data. The scheme, which can be used for real time analysis of AVHRR images in scientific and logistic activities, gives satisfactory separation of different categories. Major misclassification occurs between ice clouds and land ice because of their very similar spectral signature in the AVHRR channels. Comparison of classified samples, obtained from visual inspection of images and from application of the scheme, exhibits a confusion matrix with accuracy A=92% over areas almost free from ice clouds.
Limnological properties of Antarctic ponds during winter freezing
Authors: Schmidt S. , Moskal W. , De Mora S. J. , Howard-Williams C. , Vincent W. F.
Published: December 2007

Two shallow ponds at Cape Evans, Ross Island, were sampled at 1–2 week intervals, during winter freezing throughout the winter and during the subsequent melt period, to examine the physical and chemical conditions imposed on the biota during the year. Liquid water was first detected at the base of the ponds in late December. During the main summer melt period conductivities were less than 10 mS cm−1 with maximum daily temperatures around 5°C. The bottom waters became increasingly saline during freezing and water temperatures decreased below 0°C; by June the remaining water overlying the sediments had conductivities >150 mS cm−1 and temperatures of −13°C. Calcium carbonate, then sodium sulphate precipitated out of solution during early freezing. The dominant nitrogen species was dissolved organic-N which reached 12 g m−3 in Pond 1 just prior to final freeze up. The organic and inorganic forms of nitrogen and dissolved reactive phosphorus increased with increasing conductivity in the ponds. The behaviour of particulate-N and particulate-P mirrored that of chlorophyll a with a peak in March-April and a second higher peak just before final freeze-up. This study provides clear evidence that organisms which persist throughout the year in Antarctic coastal ponds must be capable of surviving much more severe osmotic, pH, temperature and redox conditions than those measured during the summer melt. Deoxygenation, pH decline and H2S production, however, point to continued respiratory activity well into the dark winter months.
Petrogenesis of orthogneisses in the Dry Valleys region, South Victoria Land
Authors: Cox Simon C. , Allibone Andrew H.
Published: December 2007

Granitoid gneisses intercalated with Koettlitz Group metasediments in the upper Ferrar, Taylor and Wright valleys of South Victoria Land comprise various hornblende+biotite orthogneisses and biotite orthogneisses, including the km-scale Dun and Calkin plutons. K-feldspar megacryst inclusion textures and discordant cross-cutting relationships with enclosing metasediments are interpreted as firm evidence of an intrusive origin for hornblende+biotite and biotite orthogneiss. The scale of several concordant orthogneiss bodies (including the Dun and Calkin plutons), the presence of mafic enclaves, and relict flow differentiation in hornblende+biotite orthogneiss are also compatible with a plutonic origin. Orthogneisses were emplaced prior to deformation that produced macroscopic upright, tight, folds about NW-trending axes. Petrography and geochemistry indicate I-type affinities for hornblende+biotite orthogneisses and the Dun Pluton. Hornblende+biotite and biotite orthogneisses (with the exception of the Dun Pluton) are part of a single petrogenetic suite, together with younger Bonney, Valhalla, and Hedley plutons. Emplacement of a continuum of I-type intrusives is envisaged which spanned Koettlitz Group deformation, and possibly caused much of the deformation. Hornblende+biotite and biotite orthogneisses are deformed precursors to the younger Bonney, Valhalla, and Hedley plutons. The Dun Pluton contains Fe-rich salitic clinopyroxene relicts and exhibits a unique geochemistry. It is rich in Sr, Al2O3, Na2O, and poor in FeO, K2O, Rb, Y, V. Chemical and petrographic features indicate an evolved body, possibly derived from a primitive source distinct from other orthogneisses and granitoids.
Introduction and extinction of brown trout (Salmo trutta L.) in an impoverished subantarctic stream
Authors: Cooper J. , Crafford J.E. , Hecht T.
Published: December 2007

Brown trout were introduced to the Van den Boogaard River on subantarctic Marion Island in 1964, and a small population became established. The last individual was seen in 1984, and the species is now considered to be extinct on the island. Their diet was exclusively allochthonous, with snails and spiders predominating. Ages estimated at six to eleven years showed that spawning must have occurred since the original introduction. Since the Van den Boogaard River enters the sea via a waterfall, it is postulated that trout were not able to practice an anadromous life-style, and that this, as well as other factors connected with the impoverished nature of the stream, led to dwarfing of the resident population. No further introductions of alien fish to Marion Island should be contemplated.
Biochemical composition and photosynthate distribution in sea ice microalgae of McMurdo Sound, Antarctica: evidence for nutrient stress during the spring bloom
Authors: Lizotte Michael P. , Sullivan Cornelius W.
Published: December 2007

The nutrient status of microalgae inhabiting sea ice in McMurdo Sound, Antarctica was evaluated during the peak and decline of the spring bloom in November and December. Natural populations of microalgae were analysed for C, N, chlorophyll a, protein, lipid, polysaccharide, and low-molecular-weight carbohydrate content, and for the distribution of 14C-labelled photosynthate into macromolecular fractions. Ratios of N:C and protein to carbohydrate (PR:CHO) were similar to values reported for nutrient-limited phytoplankton. Biochemical ratios and 14C-photosynthate allocation patterns suggest that microalgae from congelation ice habitats may be more nutrient-stressed than those from underlying platelet ice habitats. This trend would be consistent with the presumed gradient of seawater nutrient influx through the platelet layer to the bottom congelation ice habitat. Microalgae from congelation ice subjected to an experimental depletion of nutrients (particularly nitrate) showed decreased N:C, PR:CHO, and allocation of 14C-photosynthate to proteins. This evidence suggests that sea ice microalgae are nutrient-stressed during the peak and decline of the spring bloom in McMurdo Sound, which presumably begins when microalgal biomass concentrations and demands for growth reach or exceed the rate of nutrient supply from underlying seawater.
Satellite tracking of wandering albatrosses (Diomedea exulans) in the South Atlantic
Authors: Prince P. A. , Wood A. G. , Barton T. , Croxall J. P.
Published: December 2007

The movements of two wandering albatrosses, one of each sex, breeding at South Georgia, were tracked using satellite telemetry, particularly to assess whether such birds could be at risk from longline fishing operations in the subtropics. Full details of the performance (number and quality of uplinks) of the Toyocom transmitters are provided, together with data on flight speeds and night and daytime travel by the albatrosses. The female, tracked for seventeen days—covering three foraging trips totalling 13951 km - had a much more northerly distribution than the male, which made two trips to sea during the same period and travelled a minimum distance of 9280 km. On one trip the female frequented the area off Brazil known to be used for longline fisheries. The distributional differences between the sexes support earlier suggestions, based on at-sea observations, that the observed high mortality rates of South Georgian females could be due to a greater likelihood of incidental mortality in longline fishing. These results also show that the presence of females off Brazil can include birds still rearing chicks, rather than simply representing post-breeding dispersal.
Extreme southern locations for moss sporophytes in Antarctica
Authors: Seppelt R.D. , Green T.G.A. , Schwarz A-M.J. , Frost A.
Published: December 2007

Abundant immature sporophytes of the moss Pottia heimii are reported from the Lower Taylor Valley, McMurdo Dry Valleys and from Cape Chocolate, Victoria Land. These finds extend the reported southern limit for the occurrence of abundant moss sporophytes to 77° 55′S.
Cytogenetical study of Pringlea antiscorbutica R. Br. and Ranunculus moseleyi Hook. f. from the Kerguelen Islands
Authors: Hennion F. , Couderc H.
Published: December 2007

Pringlea antiscorbutica R. Br. (Brassicaceae) and Ranunculus moseleyi Hook. f. (Ranunculaceae) are two species endemic to the subantarctic phytogeographical zone of the south Indian Ocean (Marion and Prince Edward, Crozet, Kerguelen and Heard Islands) (Chastain 1958). The first species is the well-known “Kerguelen cabbage”, and for this taxonomic anomaly a monospecific genus was created (Hooker 1848). The only chromosome count available is by Hamel (1951). The second species Ranunculus moseleyi was first believed to be a strict endemic of the Kerguelen Islands, and then apparently was recorded on Crozet and Marion Islands (Greene & Walton 1975).
Thelodont scales from the Middle-Late Devonian Aztec Siltstone, southern Victoria Land, Antarctica
Authors: Turner S. , Young G. C.
Published: December 2007

A new fossil agnathan, Turinia antarctica sp. nov., based on numerous isolated scales, comes from the lower fish-bearing beds of the Aztec Siltstone. Scales from moraine at Mount Suess, originally described as selachian or psammosteid heterostracan, are referred to the new species which shows close affinity with T. gondwana from Bolivia and T. cf. hutkensis from Iran. Reassessment of the biostratigraphy of Middle Devonian turiniid scales suggests that the lower part of the Aztec Siltstone may be of Eifelian age.
ECMWF versus Hellermann & Rosenstein stress climatology of the Southern Ocean
Authors: Glowienka-Hense Rita , Hense Andreas , Völker Christoph
Published: December 2007

A time series of wind stresses computed from European Centre for Medium Range Weather Forecast (ECMWF) wind data is compared to the climatology of Hellermann & Rosenstein (HR) for the Southern Hemisphere. ECMWF stresses are generally stronger, especially in the westerly belt. However they have an overall lower meridional component than the HR data. The dominance of the half annual cycle relative to the annual wave in the zonal stress at middle to high latitudes, which is documented for independent data sets, is seen in the ECMWF but not in the HR data. ECMWF winds are also compared with measurements from three expeditions to the Weddell Sea by RV Polarstern. Good correlations between Polarstern and ECMWF winds are found but for single dates the differences are above 10 ms −1. The differences are found to be uncorrelated in space and are thus due to observational errors and to the unresolved small scale variance in the ECMWF analysed winds.
Sponge associations in the eastern Weddell Sea
Authors: Barthel Dagmar , Gutt Julian
Published: December 2007

About 1500 photographs from three different areas along the eastern Weddell Sea shelf and slope were analysed with respect to their sponge fauna. On the basis of material collected in concurrent bottom trawls, 34 sponge taxa were identified. Cluster and multidimensional scaling analysis showed the sponges to belong to different associations. Spatial extension of the associations is judged to be between several hundred meters and about 2 km. A deeper association (390–1125 m) on predominantly muddy substrates along a transect at Halley Bay is characterized by four opportunistic demosponge species; a second association on harder substrate in shallower depths (99–225m) off Kapp Norvegia is more diverse, with hexactinellids as one dominant component. A third cluster, comprising both Halley Bay and Kapp Norvegia stations (458–626 m), is dominated by four species which constitute a subcluster within the Kapp Norvegia sponge association. Densities vary strongly within clusters and in between geographically close stations. The species associations are related to different substrates, not to depth. Within single stations most species are patchily distributed. Both association structure and species distribution within single stations can be explained on the basis of the biology of the single sponge species.
PCB congeners, DDTs and hexachlorobenzene in Antarctic fish from Terra Nova Bay (Ross Sea)
Authors: Focardi Silvano , Lari L. , Marsili L.
Published: December 2007

Chlorinated hydrocarbons were measured in seven species of Antarctic fish (Pagothenia bernacchii, P. hansoni, Trematomus centronotus, T. newnesi, Chionodraco hamatus, Cygnodraco mawsoni, and Gymnodraco acuticeps) from in the Ross Sea near Terra Nova Bay (74°40'S 164°10'E). Hexachlorobenzene (HCB), pp' DDT and its derivatives DDE and DDD, and about 20 congeners of polychlorinated biphenyls (PCBs)were found in muscle and liver. Levels of pp′ DDE were positively correlated with body length in P. bernacchii and the plot of concentrations showed higher values in males than females of the same body weight class. The results confirm the presence of these chlorinated hydrocarbons in the Antarctic marine food chain and an increase of PCBs with respect to DDTs. The “fingerprint” of C. hamatus is different from that of other Antarctic organisms and of fish from other parts of the world, suggesting possible metabolic differences.
Characteristics of a novel, anaerobic, mycoplasma-like bacterium from Ace Lake, Antarctica
Authors: Franzmann P.D. , Rohde M.
Published: December 2007

An obligately anaerobic bacterium that lacked a cell wall was isolated from the hypolimnion of Ace Lake, Antarctica. Cells were very pleomorphic, forming cocci, filaments up to 25 μm in length, and annular shapes. The organism was morphologically very similar to some members of the class Mollicutes which contains two genera of obligately anaerobic bacteria, Anaeroplasma and Asteroleplasma. Like members of the class, the isolate was resistant to high concentrations of penicillin (1000 Units ml-1). Similar to Anaeroplasma, the organism had a low DNA G+C content (29.3±0.4) and produced hydrogen, carbon dioxide, acetic acid, lactic acid and succinic acid from the fermentation of glucose. However, the taxonomic status of the strain remained unclear as, unlike members of the class Mollicutes, the isolate had a relatively large genome size (2.26±0.11 × 109 daltons), did not pass through 0.45 μm pore size filters, and did not form typical mycoplasma-like colonies. The organism was psychrophilic with an optimum temperature for growth between 12°C and 13°C. A phenotypic description of the organism is given and the ecological role of the organism is inferred from its phenotype and the characteristics of its Antarctic habitat.
Radar observations of northbound migration of the Arctic tern, Sterna paradisaea, at the Antarctic Peninsula
Authors: Gudmundsson Gudmundur A. , Alerstam Thomas , Larsson Bertil
Published: December 2007

An intensive migration of Arctic terns was observed from 7–9 March 1989 in Marguerite Bay (67°50'S 67°30'W). The movement pattern and speed of tern flocks were analysed from time-lapse films of a marine navigation radar. The terns migrated north at altitudes 30–60 m asl along the inner coast of Marguerite Bay. When approaching Pourquois Pas Island, the majority veered to the NNE flying into Bourgeois Fjord. Mean flock size was 11.6 (s.e. = 1.9). The estimated total during the three observation days was about 7600 migrating terns. Analysing flight speed in relation to wind showed that the terns increased their airspeed when flying into headwinds and decreased it with following winds. The terns' airspeeds, with an estimated mean of 11.3 ms-1 (s.e. = 1.3) with no wind effect, were significantly faster than the predicted maximum range speed. It is suggested that the terns were migrating on a connecting route between the pack ice of the Bellingshausen and Weddell Seas, involving a flight across the Antarctic Peninsula. Topographical conditions are favourable for such a passage close to the observation site in Marguerite Bay, where the distance across the 1500 m high ice cap of the Antarctic Peninsula is only 37 km. It remains to be clarified if the suggested migration route is of importance for regional tern populations only, or if it is part of a circumpolar Antarctic migration pattern.
The lichen genus Umbilicaria on Livingston Island, South Shetland Islands, Antarctica
Authors: Sancho L.G. , Kappen L. , Schroeter B.
Published: December 2007

Five species of Umbilicaria are described, three of which, U. africana, U. krascheninnikovii and U. nylanderiana, have not been previously recorded from Antarctica. Distributional patterns and morphological characteristics of these species are discussed.
Acanthocephalan infection of inshore fish in two fjords at South Georgia
Authors: Zdzitowiecki Krzysztof , White Martin G.
Published: December 2007

An examination of 111 fish of eight species, including 92 immature Notothenia rossii Richardson revealed nine acanthocephalan species, including four Echinorhynchida occurring in the alimentary tract and five Polymorphida in the body cavity. Echinorhynchida were much more numerous (87% specimens of 4855 collected), especially Metacanthocephalus johnstoni Zdzitowiecki (the dominant species) and Aspersentis megarhynchus (Linstow). The Polymorphida parasites of seals (three species) were more abundant than species parasitic in birds (two species). Association of most of species, (except Corynosoma bullosum (Linstow) and Echinorhynchus spp.), with the inshore (fjord) environment was confirmed. The species diversity, prevalence and density of infection increased with the size of immature N. rossii. Differences in acanthocephalan occurrence and changes with time are related to differences in host distribution and abundance. For example, the occurrence of C. arctocephali in N. rossii at South Georgia is related to the increase of the fur seal population. A list of acanthocephalans in fish at South Georgia and the South Shetland Islands (14 species in total) is included.
Retention of precipitation nitrogen by Antarctic mosses, lichens and fellfield soils
Authors: Greenfield L.G.
Published: December 2007

Retention of mineral elements in precipitation by mosses and lichens involving ion exchange and chelation mechanisms is a source of nutrients for these biota growing on rocks and nutrient poor soils (Brown 1987, Crittenden 1989). In qualitative work not involving nitrogen (N) Allen et al. (1967) demonstrated that fresh Antarctic mosses treated with hydrochloric acid could retain Na, P, Ca and K after leaching with concentrated solution of these elements. Ahumic fellfield soils are widespread in Antarctica and support sparse plant growth. This short note reports the results of work designed to show that fellfield soils and plants may obtain most of their N from atmospheric precipitation.
A Cretaceous hermit crab from Antarctica: predatory activities and bryozoan symbiosis
Authors: Aguirre-Urreta M.B. , Olivero E.B.
Published: December 2007

A hermit crab assigned to Paguristes sp. is described from James Ross Island, Antarctica. The fossil was obtained from the Gamma Member of the Santa Marta Formation of late Campanian age. The specimen is associated with an external mould of the gastropod Taioma, that was encrusted by a colony of ascophoran bryozoans. Another specimen of Taioma shows typical predatory marks in the outer lip that are attributed to the action of pagurids. It is concluded that the particular dwelling habits of the hermit crabs, their symbiosis with bryozoan, and their predatory activities were already established by the end of the Cretaceous.
Glacier fluctuations on South Georgia during the 1970s and early 1980s
Authors: Gordon John E. , Timmis Roger J.
Published: December 2007

South Georgia is a highly glacierized island with a range of glacier types including corrie, valley and tidewater ice bodies. Glaciologically, it occupies a strategic location between South America and the Antarctic Peninsula and is potentially an important locality for establishing glacier-climate relationships in the region. Baseline surveys of ice front positions and ice surface profiles have been repeated to determine recent changes in several glacier types. Corrie and small, land-based valley glaciers have continued to thin and recede during the period of study, following an advance during the 1930s. Their behaviour primarily reflects the effects of seasonal temperature variations in controlling net balances, and particularly the climatic warming since 1950. The larger valley and tidewater glaciers display a lagged response and in the 1970s were at their most advanced positions since the Little Ice Age of the 17–19th centuries. However, in the last few years they too have commenced to thin and recede.
An Eocene wrasse (Perciformes; Labridae) from Seymour Island
Authors: Long Douglas J.
Published: December 2007

A nearly complete lower pharyngeal tooth-plate from a large (over 60 cm long) fossil wrasse (Perciformes: Labridae) was recently recovered from the middle to late Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula. This find increases the number of teleosts from the Eocene of Antarctica to five taxa, and further illustrates the diversity of the ichthyofauna in the Eocene Weddellian Sea prior to wide-scale climatic change in the Southern Ocean. The fossil wrasse represents the first occurrence of this family in Antarctica, and is one of the oldest fossils of this family from the Southern Hemisphere. Wrasses are not found in Antarctic waters today, and probably became extinct during the Oligocene due to a combination of climatic change, loss of shallow-water habitat, and changes in the trophic structure of the Wedell Sea.
A microbarograph for internal gravity wave studies in Antarctica
Authors: Anderson P.S. , Mobbs S.D. , King J.C. , McConnell I. , Rees J.M.
Published: December 2007

Measurement of pressure fluctuations provides the best means of detecting atmospheric internal gravity waves at the Earth's surface. We have developed an instrument which is sufficiently sensitive to detect the small pressure fluctuations associated with such waves yet robust enough for deployment in an Antarctic environment. The instrument incorporates several novel features, both in its design and in the method of deployment used. A prototype instrument has been successfully deployed at the British Antarctic Survey's Halley Station during 1989. The design of an experiment using an array of six improved instruments is briefly described.