bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of Antarctic prospective sedimentary basins
Authors: Ivanov V.L.
Published: December 2007

No less than 15–20 sedimentary basins are now known on the Antarctic continental landmass and surrounding continental shelves. Reconstruction of their tectonic and stratigraphic evolution is a specialized task. Owing to the polar position of the continent, the Pacific and Atlantic global geostructures are closely spaced there and the interplay between them is strong enough to result in hybridization of the characteristic tectonic features of the various basins. The present morphostructure of the southern polar region of the Earth is characterized by a prominent circumpolar zoning. Therefore, the sedimentary basins form a gigantic ring along the continental margin, including both the shelf proper and the edge of the continent. Within the ring, the basins are associated with different types of margins successively replacing each other, from the Mesozoic magmatic are in the Pacific segment to the classic passive margin off East Antarctica. The formation of the sedimentary basins in the Antarctic segment of the Pacific mobile belt was a part of a single process of geosynclinal development, whereas on the craton flank the process was superposed on the continental structures by rifting during Gondwana fragmentation. During post-break-up tectonism, continental glaciation played an important part in the formation of the sedimentary basins.
First Aspidorhynchidae (Pisces: Teleostei) from Antarctica
Authors: Richter Martha , Thomson M.R.A.
Published: December 2007

A new fossil teleost, belonging to the family Aspidorhynchidae Nicholson & Lydekker, Aspidorhynchus antarcticus sp. nov., was obtained from a block of reworked Upper Jurassic tuffaceous mudstone in the lower (Albian) part of the mid-Cretaceous Whisky Bay Formation of James Ross Island, Antarctic Peninsula. Additional material, assignable to Aspidorhynchus sp., was collected from in situ Upper Jurassic marine rocks (Nordenskjöld Formation) at Longing Gap, northern Antarctic Peninsula. Not only is this the first reported occurrence of the family from Antarctica, it is also the first unequivocal record of Aspidorhynchus outside Europe; prior to this discovery, the genus had only been reported with certainty in marine deposits from the Middle Jurassic to Lower Cretaceous of England, France and Germany. This is the earliest neopterygian fish so far recovered from marine rocks in the Antarctic.
Studies of atmospheric internal gravity waves at Halley station, Antarctica, using radiosondes
Authors: Mobbs S.D. , Rees J.M.
Published: December 2007

Analysis of high-resolution data from slow-ascent radiosondes released at Halley station, Antarctica (75°38′S, 26°40′W), shows that internal gravity wave phenomena are frequently present in the lower troposphere. There is a strong tendency for these waves to induce a vertical transport of the SE-NW component of momentum, this being the component perpendicular to the alignment of regular ridges in the ice shelf on which the base is built and is independent of the mean wind direction. A method for estimating the variation of the momentum fluxes with height is described. Results show that momentum flux divergences equivalent to accelerations of about 10 ms−1 per day are common at Halley.
Antarctic microbes, endemism and environmental monitoring
Authors: Vincent W.F.
Published: December 2007

The last decade of Antarctic ecological research has seen a growing awareness of the pre-eminent role played by microscopic life-forms throughout this region of the biosphere. Yet despite much new information, fundamental questions remain about the species diversity and community structure of the Antarctic microflora. There are major deficiencies in our knowledge of all microbial groups, and the information base is especially inadequate for the ice-free and coastal regions increasingly subject to human impacts.
Antarctic fish muscles — structure, function and physiology
Authors: Johnston Ian A.
Published: December 2007

The structure and function of swimming muscles in Antarctic fish is reviewed, the emphasis being on the highly endemic sub-order Notothenioidei. Adult stages of the vast majority of species swim at low speeds using large pectoral fins (labriform locomotion). This is supplemented with sub-carangiform swimming in pelagic juvenile stages and in the adult stages of some other species. The thrust for sustained activity is provided by the recruitment of slow muscle fibres. Slow muscle myofibrils typically occur in columns one fibril thick entirely surrounded by mitochondria. The resulting high volume density of mitochondria (30–60%), and short inter-mitochondrial spacing, is thought to represent an adaptation which serves to compensate for the detrimental effects of low temperature on enzyme reaction and diffusion rates. Sub-carangiform swimming is used to achieve burst speeds associated with prey capture and/or predator avoidance. Burst speeds require the recruitment of fast twitch fibres in the myotomes. In many demersal species the energy supply for burst swimming largely comes from phosphogen hydrolysis, and the capacity of fast twitch fibres for anaerobic glycogenolysis is severely reduced. Antarctic fish are characterized by delayed maturation, slow growth and low metabolic rates. The fast myotomal muscles of adult stages often contain few fibres less than 80 μm diameter, fibres 200–450 μm diameter forming the major size class in numerous species. It is therefore likely that hyperplasia ceases at a relatively early stage in development and that subsequent muscle growth involves hypertrophy of existing fibres. Studies of the contractile properties of isolated muscle fibres suggest that low temperature limits maximum swimming performance in Antarctic fish. Kinematic data suggest that this is most noticeable for juvenile stages, which have higher maximum tail-beat frequencies than adults.
Molecular adaptation of the blood of Antarctic teleosts to environmental conditions
Authors: Prisco Guido Di , D'Avino Rossana
Published: December 2007

Following the break-up of Gondwana, the drift of Antarctica to its present position and the establishment of the Antarctic Convergence, fish evolution was characterized by adaptation to progressive cooling of the environment. The decrease of erythrocyte number and haemoglobin concentration in the blood of Antarctic teleosts raises several questions concerning the physiology of respiration and the enzymatic role of erythrocytes. Our study of the molecular basis of cold adaptation includes the relationship between molecular structure and biological function of haemoglobins. Species of the suborder Notothenioidei, largely confined within the Convergence, have only one major haemoglobin, which displays the Root effect in oxygen binding; on the other hand, Zoarcidae (a family found at all latitudes) have four or five haemoglobins, only one of which displays the Root effect. In addition, our data indicate that the physiological relevance of erythrocyte-like cells, present in very small number in the blood of haemoglobinless Channichthyidae, may be linked to higher content of enzymes, such as glucose-6-phosphate dehydrogenase, in comparison with erythrocytes of red-blooded fishes.
The distribution of zooplankton in an Antarctic fjord at South Georgia during summer and winter
Authors: Ward Peter
Published: December 2007

Zooplankton was sampled intensively with an RMT 1+8M system in the fjord of Cumberland East Bay, South Georgia during late winter 1983 and summer 1987. In summer, biomass was highest in the surface 20 m, reaching 142 g dw/1000 m3. Copepods dominated the zooplankton comprising 96–99% by numbers, of which 80–90% occurred in the top 100 m of the 265-m water column. The small clausocalanid Drepanopus forcipatus was particulary abundant. With increasing depth the proportion of non-copepod biomass, principally Mysidacea and Amphipoda increased significantly. Biomass throughout the water column in winter was generally 4–5 times lower than in summer although again copepods, and in particular D. forcipatus and members of the Metridinidae, still numerically dominated the plankton. Biomass levels were some 2–3 times greater than those found in Antarctic oceanic regions but were comparable with estimates from some boreal fjords. The mixture of neritic and oceanic species encountered, and the seasonal presence of some gelatinous zooplankton, particularly ctenophores, appears typical of the community structure of many fjord ecosystems.
Random vibration of floating ice tongues
Authors: Gui E.H. , Squire V.A.
Published: December 2007

A normal mode approach is used to model the behaviour of a linearly-damped, elastic, ice beam floating on a fluid foundation and subjected to a random distributed loading. As an example, two loading regimes are considered to act on the Erebus Glacier Tongue, McMurdo Sound: broad bandwidth (‘white noise’) loading, and an ocean wave-type pressure distribution beneath the tongue. For white noise input, the root mean square (rms) deflexion is found to good accuracy within the first few modes, but the rms bending moment increases with the number of modes included in the summation due to the unlimited frequency content of the forcing. Solutions for the rms deflexion and bending moments quickly converge to their mathematical limit after six modes when the forcing is due to ocean waves. A local maximum in rms bending moment near the end of the beam confirms that waves may be important as a mechanism for iceberg calving.
Treaty on Antarctic minerals and oil – what impact on science and environment?
Authors: Behrendt John C.
Published: December 2007

The Convention on the Regulation of Antarctic Mineral Resource Activities (CRAMRA) was adopted in 1988. Of legitimate concern to all Antarctic scientists is CRAMRA's impact on the Antarctic environment and on the conduct of research; the treaty will have a positive effect on both.
Biotic and chemical characteristics of some soils from Wilkes Land, Antarctica
Authors: Heatwole Harold , Saenger Peter , Spain Alister , Kerry Elizabeth , Donelan John
Published: December 2007

Numbers of micro-organisms in soils from Wilkes Land varied widely. Bacteria, yeasts and filamentous fungi occurred in all samples analysed and the numbers of bacteria was positively correlated with the numbers of yeasts, and with pH. Moss protonema and seven species of algae and cyanobacteria were also present and measurable amounts of chlorophylls a, b and c were extracted from some samples. Only a few sites, those with moist sandy or gravelly soils free of extensive moss or lichen cover, contained the single mite species recorded.
Palaeoenvironmental reconstruction from redeposited weathered clasts in the CIROS-1 drill core
Authors: Hall Kevin , Bühmann Dieter
Published: December 2007

The occurrence and nature of weathered clasts in the CIROS-1 drill core from McMurdo Sound was recorded. These data showed both associations of weathered material with particular lithofacies and that certain lithologies were preferentially weathered. XRD analysis of weathering rinds from two lithostratigraphic core units suggest that such weathering data can provide evidence of terrestrial palaeoenvironmental conditions that may be otherwise unobtainable.
Early Palaeozoic history of the upper Beardmore Glacier area: implications for a major Antarctic structural boundary within the Transantarctic Mountains
Authors: Rowell A.J. , Rees Margaret N.
Published: December 2007

The central and western Transantarctic Mountains appear to be divided longitudinally by one or more terrane boundaries that separate two regions characterized by different Lower Palaeozoic successions. Re-examination of the upper Beardmore Glacier area and reinterpretation of its Early Palaeozoic stratigraphy emphasizes the strong similarity between it and the Byrd Group outcrops in the area between the Byrd and Nimrod glaciers. This similarity demonstrates that for several hundred kilometres the Cambrian succession of an inboard region is largely devoid of volcanic rocks but includes fossiliferous Lower Cambrian platformal limestones that are overlain unconformably by coarse basin-fill deposits. The latter probably include beds of Middle and perhaps early Late Cambrian age that were themselves deformed prior to the Devonian. Erratic blocks indicate that comparable successions may have been developed as far west as the Whichaway Nunataks. The inferred geological history of this part of the continental margin, which is commonly regarded as autochthonous, stands in contrast to that of more outboard regions where thick volcanic sequences occur in expanded stratigraphic sections that include shallow-marine Middle and Late Cambrian deposits. We consider that these regions, predominantly the Queen Maud and Theil mountains and the Neptune Range of the Pensacola Mountains, constitute one or more displaced crustal blocks. The boundary between them and the inboard sequence adjacent to the craton is probably a series of large strike-slip faults that may have been initiated during the Early Palaeozoic and have been active episodically since then.
Problems in the identification of anthropogenic hydrocarbons against natural background levels in the Antarctic
Authors: Cripps G.C.
Published: December 2007

Hydrocarbons in the environment occur as complex mixtures. The detection of low-level anthropogenic contamination can be difficult as many of the compounds can also be found in biogenic materials. Results obtained in the Antarctic show that accepted methods of distinguishing biogenic from contaminating hydrocarbons are inconsistent. The samples taken from South Georgia in the vicinity of derelict whaling stations had odd-to-even carbon number ratios in the range 0.8–1.0. An offshore site had the highest levels for phytane and the lowest for pristane. The pristane-to-phytane ratio varied between 0.4 and 1.4 and contradicted the interpretation of the odd-to-even ratio at several sites. A value of less than 1.0 for these ratios has been taken to indicate anthropogenic origin. A number of polycyclic aromatic hydrocarbons were detected at all the sites, but the concentration gradient did not correspond with that of the n-alkanes. It is therefore recommended that recognition of anthropogenic input is based on quantification of all compounds against a well-defined baseline. The source of the pollution can then be estimated from the distribution patters of the hydrocarbons.
Algae concentrated by frazil ice: evidence from laboratory experiments and field measurements
Authors: Garrison D.L. , Close A.R. , Reimnitz E.
Published: December 2007

A number of studies have suggested that high concentrations of organisms in sea ice may be the result of harvesting and concentration by frazil ice. Laboratory experiments have shown that frazil ice can concentrate organisms from two to four times above levels in the underlying water. The concentrations in nature, however, can be considerably higher. The apparent discrepancy between laboratory results and field observations can be explained by the longer temporal and spatial scales that allow more contact of ice crystals with particles and with one another in the sea. It is also likely that small-scale circulation features, such as Langmuir circulation, enhance the ability of frazil ice to concentrate organisms in a natural setting.
A two-dimensional model for the thermohaline circulation under an ice shelf
Authors: Hellmer H.H. , Olbers D.J.
Published: December 2007

The production of Antarctic Bottom Water is influenced by Ice Shelf Water which is formed due to the modification of shelf water masses under huge ice shelves. The coupling of inflow conditions, thermohaline processes at the ice shelf base and the sub-ice shelf circulation is studied with a two-dimensional thermohaline circulation model which has been developed for a section perpendicular to the ice shelf edge. Different boundary conditions appropriate to the Filchner Ice Shelf regime are considered. The model results indicate that, in general, shelf water is transported toward the grounding line, where at the ice shelf base melting occurs with a maximum rate of 1.5 my−1. Accumulation of ice takes place at the end of the melting zone close to the ice shelf edge with a rate on the order of 0.1 my−1. The location of this accumulation zone determines whether or not the density increase by salt rejection causes an upper circulation cell and the separation of the modified water mass from the ice shelf base at mid-range depth. At the ice shelf edge the simulated temperature, salinity, helium and δ18O values for the temperature minimum layer are typical for Ice Shelf Water. However the sub-ice shelf circulation is highly variable as well as sensitive to changes in boundary conditions. Moderate changes in the characteristics of the inflowing water or in sea-floor topography may double the intensity of the circulation. Non-linear processes in the accumulation zone cause variabilities which can be described by an ice shelf edge oscillator influencing the entire circulation regime.
Geology and geochronology of McMurdo Volcanic Group rocks in the vicinity of Lake Morning, McMurdo Sound, Antarctica
Authors: Kyle Philip R. , Muncy H. Lee
Published: December 2007

Trachyandesite lava flows and trachytic dykes exposed at ‘Gandalf Ridge’ and near Lake Morning on the northern slopes of Mount Morning represent the oldest exposed volcanic rocks in the Erebus volcanic province of the McMurdo Volcanic Group. Conventional whole rock K-Ar age determinations show the rocks are mid-Miocene, ranging between 14.6 and 18.7 Ma. North–south trending faults, which parallel the Transantarctic Mountains, cut the dated dykes. The faults are probably part of a broad fault zone which bounds the uplifted Transantarctic Mountains and the down-dropped Ross Sea/Ross Ice Shelf embayment.
Reference systems of maps and geographic information systems of Antarctica
Authors: Sievers Jörn , Bennat Heinz
Published: December 2007

The necessity for uniform reference systems for conventional maps (analogue) and geographic information systems (digital) is discussed. It is recommended that the following scales and projections are used for Antarctic maps: general maps at scales smaller than 1:1 000 000 should use a stereographic projection. Maps up to a scale of 1:1 000 000 should be compiled according to the specifications of the International Map of the World (IMW) 1:1 000 000. Ellipsoids are used as reference surfaces for the various map projections. Differences of the ellipsoidal parameters of the WGS72 and WGS84 systems have to be considered if accuracies better than 10 m are required. Geographic information systems may store data in vector or raster format and in geographic or in geodetic coordinates. For a raster format which is referred to the geographic (spheroidal) grid the term of ‘geographic raster’ is introduced, in contrast to the ‘geodetic raster’ which is referred to a plane cartesian coordinate system. The Institut für Angewandte Geodäsie (IfAG) is establishing the ‘Geocoded Information System Antarctica’ (GIA) using digital satellite image recordings. Internal storage of data in the GIA is in the form of the geodetic raster (and not by spheroidal coordinates). For the scale range 1:250 000 to 1:1 000 000 the size of the raster element is 60 m × 60 m. For smaller scales, satellite image data of a raster width of 240 m × 240 m are preferred.

‘All cartographers' trouble began with the abolition of the flat-Earth theory ’
Acoustic sounding of the atmospheric boundary layer at Halley, Antarctica
Authors: Culf Alistair D.
Published: December 2007

The records obtained from a monostatic acoustic sounder run at Halley, Antarctica, have been analysed with the use of data from instruments on a 32 m mast and from radiosonde ascents. Echoes representing ground-based layers, waves, and shallow gravity currents are discussed. The spiky ground-based echo is related to a westerly surface wind, whilst a layered wavy flow is related to surface easterlies. Such relationships are consistent with the sloped inversion wind regime at Halley.
Impact of incidental mortality on Antarctic marine vertebrates
Authors: Croxall J.P.
Published: December 2007

Only a few years ago most interested people thought (and many said in print) that accidental killing of Antarctic animals as a consequence of commercial fishing operations was minimal to non-existent. We now know that species in three major groups (fish, seals, seabirds) are seriously threatened by such incidental mortality.
The Cenozoic history of Antarctica and its global impact
Authors: Webb Peter-Noel
Published: December 2007

The Antarctic continent and the peripheral ocean regions are the primary source of information on the Cenozoic cryosphere and events leading up to its development at least 36 million years ago. From a variety of data it is now apparent that the southern high latitudes have been subjected to a dynamic alternation of ice sheet expansion and decay through the late Palaeogene and Neogene. This history of climate change was accompanied by, and certainly strongly influenced by, significant vertical and horizontal lithosphere changes, including the evolution of major internal seaways and mountain ranges. The imprint of this record is preserved in the marine successions of the polar basins, in the world's bathyal and abyssal ocean basins and in the continental shelves of other continents, including those of the Northern Hemisphere. The Antarctic and extra-Antarctic terrestrial and marine data bases have developed separately in the past three decades and geospheric and biospheric information must now be integrated across latitudes. Future success in deciphering climate change depends on a better understanding of glacial–deglacial cycles from the point of view of both direct Antarctic and indirect or proxy extra-Antarctic data, through the complete temporal range of 107 to 103 years. Unfortunately, much of the high latitude record for the past 65 million years of earth history is presently veiled by thick ice sheets/ice shelves and deep and often ice-covered marine waters. Without the intensive application of the most advanced remote sampling equipment on the continent and in the Southern Ocean it will be difficult for this region to contribute significantly to global change and global climate programmes.
A one-dimensional mixed layer model beneath the Ross Ice Shelf with tidally induced vertical mixing
Authors: Scheduikat M. , Olbers D.J.
Published: December 2007

The dense High Salinity Shelf Water (HSSW) which spreads out below parts of the Ross Ice Shelf represents a heat-reservoir that can induce ablation if it comes into contact with the ice shelf base. One source of the mechanical energy necessary to lift the dense HSSW is small-scale turbulence induced by the shear of tidal currents at the sea-floor and at the ice shelf base. A one-dimensional Kraus-Turner-type model which is forced by a barotropic tidal current is coupled to the ice shelf by postulating that the ice-water interface is at the freezing point. The calculations indicate that the results of this two-layer approach allow a classification into a freezing and melting regime, depending strongly on the variability of the tidal currents with time and less on the intensity and the corresponding high production rate of turbulent kinetic energy. Based on an extended three-layer model ablation rates exceeding 0.4 m yr−1 are obtained in the south-eastern part of the Ross Ice Shelf. Advection processes in the mixed layer directly beneath the ice shelf base are not considered. These results can therefore be regarded as indicating the maximum amount of ablation occuring in the deeper reaches of the ice shelf cavity. Application of the three-layer model to the J9-area in the central Ross Ice Shelf indicate a tidally induced vertical heat flux of 1.8 W m−2 and a corresponding melting rate of 0.17 m yr−1. As supported by ice core measurements, however, an accumulation rate of 0.03–0.05 m yr−1 is estimated due to advection of freshwater produced immediately south of the J9-area.
Fish remains from the Santa Marta Formation (Late Cretaceous) of James Ross Island, Antarctica
Authors: Richter Martha , Ward David J.
Published: December 2007

Isolated fish remains including a tooth of the oldest described frilled shark, Chlamydoselachus thomsoni sp. nov. are described and figured from the Santa Marta Formation (Santonian–Campanian, Late Cretaceous) of James Ross Island, Antarctic Peninsula. Their geological and palaeoecological context is considered in the light of recent geological studies.
A review of the climate of Mawson – a representative strong wind site in East Antarctica
Authors: Streten N.A.
Published: December 2007

An analysis is made of the climate of the Australian Antarctic station Mawson (67.6°S, 62.9°E) and its hinterland in the light of 30 years of observations and of previous investigations. Data are presented on free atmosphere temperature and wind structure, the synoptic meteorology of the region, solar radiation, surface temperature, sea ice, wind and weather. Emphasis is placed on the characteristics of the shallow south easterly katabatic winds averaging 11.1 m s−1 throughout the year and the frequent periods of intense gale associated with the effects of major Southern Ocean depressions. The climate of Mawson is believed to be typical of much of the coast of East Antarctica in regions where the ice-cap falls steeply to sea level.
Remote sensing in Antarctica and the Southern Ocean: applications and developments
Authors: Maslanik James A. , Barry Roger G.
Published: December 2007

Remote sensing provides the means to study features and processes that are not easily accessible or amenable to direct observations. The polar regions, and Antarctica in particular, offer a variety of examples where the ability to observe from afar is necessary or highly desirable. In particular, studies of ice shelf processes, changes in the sea-ice cover, and ice-ocean-atmosphere investigations must rely in large part on measurements from aircraft and satellites. The polar regions present a unique set of problems that complicate applications and limit the usefulness of certain sensors; new instruments planned for launch in the 1990s will help resolve many of these difficulties. Examples of remote sensing applications for the study of the continent, drifting ice, ocean, and atmosphere demonstrate ways that existing data as well as new observations can be used to aid polar research.
Demersal fish fauna of the Weddell Sea, Antarctica
Authors: Ekau Werner
Published: December 2007

The demersal fish fauna of the southern and eastern Weddell Sea is described. The following species were recorded for the first time in this area: Aethotaxis mitopteryx, Bathyraja eatoni, B. Maccaini, B. sp2 (FAO-list), Bathydraco marri, Dissostichus mawsoni, Macrourus holotrachys, Muraenolepis sp., Notothenia coriiceps, Notothenia kempi, Psilodraco spec. and Trematomus nicolai. In terms of biomass the dominant species on the very narrow eastern continental shelf were Chionodraco myersi (49%), Trematomus eulepidotus (11%), C. hamatus (7%), T. lepidorhinus (6%), Pagetopsis maculatus (5%) and T. scotti, Cryodraco antarcticus, Cygnodraco mawsoni and Pleuragramma antarcticum (4% each). The highest density of individuals and greatest biomass was found between 400 and 650 m water depth. Here, C. myersi, T. eulepidotus and T. lepidorhinus dominated the catches. The shallow shelf area was inhabited by smaller species such as T. scotti, T. centronotus, P. maculatus, Artedidraco skottsbergii, A. shackletoni, and Prionodraco evansii. In the southern Weddell Sea Akarotaxis nudiceps, Dolloidraco longedorsalis, Gerlachea australis, Pleuragramma antarcticum, and Trematomus loennbergi were dominant. Members of the Channichthyidae occurred only occasionally, most of these are Dacodraco hunteri. The biomass of the demersal fish fauna was estimated to be 0.3 to 1.6 t km−2 on the Vestkapp shelf and 0.1 to 0.4 t km−2 for Gould Bay. Biomass values greater than 1.0 t km−2 were found at the shelf edge.
Snow algae of the Windmill Islands, continental Antarctica. Mesotaenium berggrenii (Zygnematales, Chlorophyta) the alga of grey snow
Authors: Ling H.U. , Seppelt R.D.
Published: December 2007

A saccoderm desmid Mesotaenium berggrenii forma (Mesotaeniaceae) occurring as a major component of the snow algal flora is reported from the Windmill Islands region of Continental Antarctica. Stages of the life cycle of the species are illustrated. The local distribution of the species is outlined, habitat conditions described, taxonomy, reproduction and survival strategies discussed. Morphological and nuclear size classes indicate the possibility of polyploidy in the species.
Signals of atmospheric pollution in polar snow and ice
Authors: Wolff E.W.
Published: December 2007

In their upper layers, the polar ice sheets contain a detailed record of changes in the atmosphere over the industrial period. Measurements from air bubbles in ice have shown that the CO2 content of the atmosphere has increased by 25% in the last 200 years, and that of CH4 has more than doubled. Ice core records have demonstrated a close correspondence between greenhouse gases and temperature during the last glacial cycle. Profiles of radioactive species in snow clearly document nuclear bomb tests in the atmosphere, and the recent Chernobyl accident has also left a signal in Northern Hemisphere ice. Nitrate has more than doubled in Greenland snow over the industrial period, while sulphate has more than trebled. No significant trend is seen in Antarctic snow for these anions. Pb increased 100-fold until the 1970s in Greenland snow, but concentrations appear now to be declining. A small increase is also recorded in Antarctic snow. Organochlorine compounds offer great potential for pollution studies in snow. The ability to study global scale pollution in polar ice could be hampered if there is significant local pollution. In Antarctica, impact on the atmosphere from local human activities is still mainly confined to small areas near stations.
Preliminary results of seismic reflection investigations and associated geophysical studies in the area of the Antarctic Peninsula
Authors:   The GRAPE Team
Published: December 2007

A geophysical data set including some 1400 km of reflection seismic profiles and 17000 km of gravity lines was recorded in the waters north-west of the Antarctic Peninsula during the austral spring cruise of RV Polarstern (October to December 1987). These data form a contribution to the earlier and continuing studies dealing with the tectonics of Bransfield Strait, the structure of the South Shetland Trench, and the segmentation of the adjacent oceanic crust. The seismic profiles and gravity data illustrate among other features the differential extension of Bransfield Strait and the structure and morphology of the former converging plate boundary, which vary corresponding to the time of the last ridge trench collision. Observations have been made about the active character of several oceanic fracture zones in time which meet the former plate boundary.
Snow accumulation and surface topography in the katabatic zone of Eastern Wilkes Land, Antarctica
Authors: Goodwin Ian D.
Published: December 2007

Snow accumulation and surface microrelief distributions, together with the surface katabatic wind pattern and elevation profiles, are presented for the eastern Wilkes Land katabatic wind zone. The broad-scale net accumulation distribution displays a strong negative correlation with elevation but on the mesoscale there are significant variations with respect to the elevation profile. The accumulation distribution was found to be dependent on slope aspect. Higher accumulation rates were observed on the north-east (windward) slope than those on the north-west (leeward) slope for the elevation range of 1870 m–2230 m. These higher accumulation rates are associated with the occurrence of longitudinal dunes deposited by precipitation, during synoptic events. The dependence of the accumulation distribution on aspect implies that synoptic and orographic processes are the major control on the depositional regime, and that maritime synoptic systems regularly penetrate eastern Wilkes Land to at least 2300 m elevation.
The calving and drift of iceberg B-9 in the Ross Sea, Antarctica
Authors: Keys Harry (J.R.) , Jacobs S.S. , Barnett Don
Published: December 2007

Major rifts is the Ross Ice Shelf controlled the October 1987 calving of the 154 × 35 km “B-9” iceberg, one of the longest on record. The 2000 km, 22 month drift of this iceberg and the quite different tracks of smaller bergs that calved with it have extended our understanding of the ocean circulation in the Ross Sea. B-9 initially moved north-west for seven months until deflected southward by a subsurface current which caused it to collide with the ice shelf in August 1988. It then completed a 100 km-radius gyre on the east-central shelf before resuming its north-westerly drift. Based upon weekly locations, derived from NOAA-10 and DMSP satellite and more frequent ARGOS data buoy positions, B-9 moved at an average speed of 2.4 km day−1 over the continental shelf. It was not grounded there at any time, but cast a large shadow of open water or reduced ice thickness during the austral winters. B-9 was captured by the continental slope current in May 1989, and attained a maximum velocity of 13 km day−1 before breaking into three pieces north of Cape Adare in early August 1989.
Icebergs as tracers of water movement in the Bransfield Strait
Authors: Madejski P. , Rakusa-Suszczewski S.
Published: December 2007

The direction and velocity of iceberg drift were measured during 1987 by photogrammetric methods. Drift along the southern coast of King George Island followed the NE and ENE directions of wind and water currents. The highest mean velocities (0.6–0.8 ms−1) were recorded in March and April, and the lowest velocities (0.1–0.2 ms−1) in winter, from May–July. From August–October velocities (0.4–0.6 ms−1) were higher than in November to December (0.4–0.5 ms−1). The waters flowing into Admiralty Bay came from the western part of the Bransfield Strait.
European geological initiative for the Shackleton Range
Authors: Tessensohn F. , Thomson M.R.A.
Published: December 2007

The Shackleton Range occupies a key geological position in Antarctica (Fig. 1). Its location, at the edge of the continental craton between the mobile belts of the Transantarctic Mountains (TAM) and the stable platform of Dronning Maud Land (Neuschwabenland), and its geological constitution offer possibilities for: understanding the nature of the ‘Pacific’ margin of the Antarctic craton during the Palaeozoic, distinguishing between subduction- and collision-related tectonics at an ancient continental margin, and contributing to the debate on the relationship between East and West Antarctica. The structural orientation of the range, at right angles to the trend of the TAM, has puzzled geologists ever since its discovery.
The need for geological protection in Antarctica?
Authors: Birkenmajer K.
Published: December 2007

During the past 30 years or so, the primary objects of environmental protection in Antarctica were living organisms such as penguins and seals, and their breeding grounds, terrestrial plants and their habitats. The ever growing threats to the icy continent, resulting from increasing human activities, lead SCAR, the Antarctic Treaty Consultative Parties (ATCPs), and recently also the Council of Managers of National Antarctic Programmes (COMNAP) to seek improved measures for conservation of the Antarctic fauna and flora, to actively participate in the preparation of conventions for protection of seals and other marine living organisms, and to elaborate a mandatory code for waste disposal.
Improvements in General Circulation Model performance in simulating Antarctic climate
Authors: Simmonds Ian
Published: December 2007

Increasingly, many aspects of the study of Antarctica and the high southern latitudes are being aided by various types of numerical models. Among these are the General Circulation Models (GCMs), which are powerful tools that can be used to understand the maintenance of present atmospheric climate and determine its sensitivity to imposed changes. The changes in the ability of GCMs used over the last two decades to simulate aspects of atmospheric climate at high southern latitudes are traced and it is concluded there has been a steady improvement in model products. The task of assessing model climates in high southern latitudes is made difficult by the uncertainties in the data used for the climatological statistics. It is suggested that the quality of the climates produced by most modern GCMs in many aspects cannot be said to be poor, especially considering the uncertainties in ‘observed’ climate. There is obviously need for improvements in both modelling and observations. Finally, some topics are highlighted in which the formulation of models could be improved, with special reference to better treatment of physical processes at high southern latitudes.
Alien vascular flora of Marion and Prince Edward Islands: new species, present distribution and status
Authors: Bergstrom Dana M. , Smith V.R.
Published: December 2007

The presence and distribution of alien plant species on subantarctic Marion and Prince Edward Islands is reviewed and updated. This study documents the finding of a well established population of Cerastium fontanum on Prince Edward Island. An additional taxa, Senecio sp., is recorded in association with a recurrence of Plantago lanceolata on Marion Island. Propagules of both these taxa have recently been dispersed to the island in building material imported from South Africa. The distribution of Agrostis stolonifera and Sagina apetala on Marion Island has increased markedly between 1981 and 1989.
Growth of Antarctic and temperate terrestrial Protozoa under fluctuating temperature regimes
Authors: Smith H. G. , Hughes J. , Moore S. J.
Published: December 2007

Population growth rates of Antarctic and temperate isolates of the microflagellate Heteromita globosa Stein and of the ciliate Colpoda cucullus Müller were determined during incubation both under constant 3.5° and 8.0°C, and under temperature regimes fluctuating on 24-hour cycles, between 0° and 15°C, to simulate Antarctic microclimates. Fluctuating temperatures did not inhibit growth. No growth of Colpoda occurred at 3.5°C. It is suggested that successful growth in nature depends upon the microclimate providing sufficient degree-hours per day above encystment/excystment threshold temperature (+1.5°C for Heteromita about +4°C for Colpoda). The minimum number of degree-hours above threshold needed for growth of Colpoda is estimated to lie between 48 and 96. Monitored microclimates in the maritime Antarctic do not provide enough degree-hours per day, though subantarctic microclimates are more favourable, as may be exceptionally warm localities in the continental Antarctic where daily insolation is high in summer. These data are consistent with the recorded presence of Colpoda spp. in the subantarctic and rarely in the continental Antarctic, and their absence from the maritime Antarctic.
Spinel-garnet Iherzolite nodules from alkaline-ultrabasic rocks of Jetty Peninsula (East Antarctica)
Authors: Andronikov A.V.
Published: December 2007

The petrography and mineralogy of Iherzolite nodules from an intrusive body of alkaline-ultrabasic rocks on Jetty Peninsula. The nodules are massive with a porphyritic hypidiomorphic granular texture. The main rock-forming minerals are: olivine, pyroxene, garnet and chrome spinel. The nodules are coarse granular spinel-garnet Iherzolites that are chemically similar to pyrope peridotite from Krezemze, Czechoslovakia, and pyrope-bearing peridotite from alkaline ultrabasites of Yakutia, USSR. The Al2O3 content in enstaties and Ca/(Ca + Mg) ratio in co-existing chrome diopside suggest that equilibrium conditions of the mantle mineral assemblage are: T = 875–900°C, P = 20–24 kbar, conditions typical of the spinel-pyrope facies of the upper mantle. Depths of withdrawal of the inclusions do not exceed 60–75 km. Available age determinations of the intrusive alkaline-ultrabasic rocks (145–150 Ma) suggest that alkaline-ultrabasic magmatism and withdrawal of plutonic nodules were related to rifting which resulted in the breakup of the Gondwana supercontinent in the late Mesozoic.
An Early Permian palynoflora from Milorgfjella, Dronning Maud Land, Antarctica
Authors: Larsson Kent , Lindström Sofie , Guy-Ohlson Dorothy
Published: December 2007

A preliminary palynological study of Beacon Supergroup sedimentary rocks exposed at Milorgfjella, Dronning Maud Land, has yielded a relatively rich and well preserved palynoflora dominated by spores and pollen grains, but also including acritarchs and green algae. The palynoflora is dominated by the pterophyte spores Punctatisporites gretensis, Punctatisporites parvus, Granulatisporites spp., Microbaculispora tentula Horriditriletes spp. and Verrucosisporites andersonii, and the gymnosperm pollen grains Plicatipollenites spp. and Cannanoropollis spp. Also present are the lycopod spore Jayantisporites pseudozonatus, the praecolpate pollen grain Marsupipollenites striatus and the monocolpate pollen grain Cycadopites cymbatus. The palynoflora indicates freshwater conditions or, at least, a major freshwater influence on the depositional environment. Comparison of the palynoflora with others from Gondwana suggests an Early Permian (Asselian–Sakmarian) age.
Preliminary stratigraphy of volcanoes in the Executive Committee Range, central Marie Byrd Land
Authors: Smellie J.L. , McIntosh W.C. , Gamble J.A. , Panter K.T.
Published: December 2007

Marie Byrd Land is amongst the most inaccessible and least visited regions of Antarctica. It contains a large alkaline volcanic province, with 18 large central volcanoes and numerous small satellitic centres, ranging in age from late Oligocene (c. 28–30 Ma) to Recent (LeMasurier 1990). The volcanic rocks provide an outstanding record of the late Cenozoic glacial and volcanic history of Antarctica. The volcanism has been described within a region-wide model of hot-spot impingent at the base of the crust, widespread eruption of mafic plateau lavas and the sequential release of more evolved magmas from crustal chambers beneath central volcanoes situated along a series of reactivated, orthogonal basement fractures (LeMasurier & Rex 1989). Most of the volcanoes have been studied only on a reconnaissance level.
Development of unmanned magnetometer stations for use in Antarctica
Authors: Saka O. , Sato N. , Uchida S.
Published: December 2007

Unmanned magnetometer stations (UMS) have been developed and were installed at remote location near Syowa station, Antarctica (69°S, 40°E) to perform field tests in the harsh Antarctic environment. The UMS was powered by a thermo-electric generator fuelled by kerosene (LTEG) which supplies 87 Watts continuously to the load. The LTEG and instrumentation (flux gate magnetometer, data logger, chronometer) were installed in a thermally insulated shelter (0.9 m by 1.8 m by 1.9 m). The shelter and an 800 l fuel tank were mounted on a sled, and were towed by snow tractor. The UMS were installed at Kizahasi beach, Skarvsnes (50 km south-west of Syowa) and at H-100 of the Mizuho route (100 km south of Syowa) in the early spring of 1988 and operated until the end of the year. The data obtained will be used for a study of the spatial phase and amplitude structure of the ionospheric current systems and a response of the local induction currents to them.
Ecological considerations of Antarctic ozone depletion
Authors: Karentz Deneb
Published: December 2007

Springtime ozone depletion over Antarctica has been observed for over a decade. Associated with ozone depletion is an increase in the levels of biologically harmful ultraviolet-B (UV-B) that reach the earth's surface, a situation that has prompted much controversy about the ecological effects of this atmospheric phenomenon on Antarctic ecosystems. A major hindrance to assessing the ecological impact is lack of appropriate data on Antarctic systems before the present ozone depletion cycle began. In addition, certain physical features of the Antarctic environment (clouds, snow and ice) and the UV-B photobiology (repair processes and protective strategies) of endemic species can alter the potential biological effects of this environmental stress in, as yet, undetermined ways. Increases in incident UV levels will most likely result in changes in the taxonomic structure of communities. The effects of these changes on net productivity and trophic dynamics cannot be accurately assessed without quantifying ambient doeses of UV and characterizing the UV photobiology of individual species. Both the physical features of the springtime environment and the biological responses of endemic species must be considered in future research efforts to evaluate the biological consequences of the Antarctic ozone hole.
Muscle growth in the Antarctic teleost, Notothenia neglecta (Nybelin)
Authors: Battram John C. , Johnston Ian A.
Published: December 2007

A histochemical and electron microscopy study was carried out on muscle growth in demersal stages of the Antarctic teleost Notothenia neglecta Nybelin. The total number of myotomal muscle fibres was similar in fish ranging in body mass from 11.9g to 889g. Post-anal myotomes contained around 17,000 slow muscle fibres and 70,000 fast muscle fibres. Myosatellite cells were extremely rare. The diameter of fast fibres varied from <10μm to 130μm in the smallest, and from >40μm to 450μm in the largest fish studied. Slow muscle fibre diameters in the largest fish ranged from >30μm to 260μm. Even the largest diameter slow fibres contained significant numbers of mitochondria, which suggests that the diffusion of oxygen does not limit metabolism. The results confirm that muscle fibre hyperplasia ceases prior to the demersal stages of the life history, and that subsequent muscle growth is entirely via the hypertrophy of existing fibres. Comparative studies suggest that this may be one of the factors contributing to the relatively slow rate of somatic growth in this species.
Morphological characterization of Oscillatoriales (Cyanobacteria) from Ross Island and southern Victoria Land, Antarctica
Authors: Broady Paul A. , Kibblewhite Andrew L.
Published: December 2007

Field populations of Oscillatoriales, from fresh and saline lakes and ponds, and from terrestrial habitats, are characterised on the basis of their morphology and morphometry. Fifteen morphotypes are recognized principally from the following characteristics; cross-sectional shape of the trichome, presence or absence of a calyptra on the apical cell, occurrence or otherwise of numerous trichomes within a common sheath, and trichome width distribution. Where possible morphotypes are assigned to traditional species described by earlier investigations of algae in the Ross Sea region and a reassessment is made of the early descriptions, in some cases using material from the identical locations to the original collections. The following traditional species are described; Lyngbya murrayi, Microcoleus vaginatus, Oscillatoria deflexa, O. koettlitzi, O. priestleyi, O. sancta, Phormidium autumnale and P. subproboscidea. Intraspecific morphotypes of M. vaginatus, O. priestleyi and P. autumnale are recognised on the basis of trichome width. A new species and variety of Crinalium (Crow) Winder, Stal & Mur, a genus characterized by flattened trichomes, are described from cryoconite ponds on glaciers. C. glaciale sp. nov. possesses wide, straight trichomes in contrast to C. glaciale var. helicoides nov. var. in which trichomes are narrower and helically coiled.