Showing 11862 items
1 May, 1993
The effect of low temperatures and freeze-thaw stress on photosynthetic carbon exchange in an Antarctic population of the turf-forming moss species Polytrichum alpestre Hoppe was investigated using infra-red gas analysis.…1 May, 1993
The dielectric properties of a clay and a silt soil have been studied at low water saturations at temperatures between −100°C and −15°C. The frequency range of the study (20…Read more on Dielectric properties of frozen clay and silt soils
1 May, 1993
A study of riometer, photometer, and ionosonde data from South Pole Station has revealed a class of unusual dayside absorption events which occur near local magnetic noon when South Pole…1 May, 1993 by John Turner, Thomas Lachlan-Cope
A detailed analysis of the evolution and structure of a mesoscale vortex and associated cloud comma that developed at the eastern edge of the Weddell Sea, Antarctica, during the early…Read more on A mesoscale vortex over Halley Station, Antarctica
1 April, 1993 by Mervyn Freeman, Michael Pinnock
We examine the nature of flows in the nightside auroral zone ionosphere and their relationship with concurrent geomagnetic activity by studying a three-hour interval of ground-based radar, magnetometer array and…1 April, 1993 by Hugh Corr, Robert Mulvaney
Analyses of Cl−, NO3−, SO42−, Na and Mg made on a series of surface snow samples, collected at 4 km intervals along a 116 km traverse of the Fimbul Ice…Read more on The fractionation of sea salt and acids during transport across an Antarctic ice shelf
1 April, 1993
We recorded the age of individual wing and tail feathers of Black-browed and Grey-headed Albatrosses Diomedea melanophris and D. chrysostoma of known age and breeding status at Bird Island, South…1 April, 1993
Measurements of stratospheric NO2 by ground-based visible spectrometers rely on laboratory measurements of absorption cross-sections. We review low-temperature laboratory measurements, which disagree by amounts claimed to be significant. Our recalculation…1 April, 1993
The Nordenskjöld Formation (?Oxfordian-Berriasian age) is exposed on the east coast of the Antarctic Peninsula, where it consists of interbedded ash layers and biosiliceous mudstones which accumulated under anaerobic to…1 March, 1993
A census of the breeding population of Antarctic fur seals (Arctocephalus gazella) at South Georgia was carried out during the 1990/91 breeding season. Using counts of adult females ashore at…1 March, 1993
The phenomenon of bipolarity, one of the major disjunct distribution patterns on the face of the earth, has been investigated repeatedly since the mid-nineteenth century. Running through the many hypotheses…Read more on Bipolar molluscs and their evolutionary implications
1 March, 1993
An indication of the extent of weathering on different aspects of rock outcrops on Livingston Island, Antarctica, was obtained by means of a Schmidt hammer, a cone indenter and measurement…1 March, 1993 by Eric Wolff, Robert Mulvaney
A firn core from within the polar vortex in the Weddell Sea sector of Antarctica shows nitrate peaks that occur in the spring or early summer. They are far less…1 March, 1993 by Michael Pinnock
Transient or patchy magnetic field line merging on the dayside magnetopause, giving rise to flux transfer events (FTEs), is thought to play a significant role in energizing high-latitude ionospheric convection…Read more on Observations of an enhanced convection channel in the cusp ionosphere
1 March, 1993
Because of its remoteness, Marie Byrd Land is among the most inaccessible and least visited parts of Antarctica. However, it contains a very poorly studied, large Cenozoic alkaline volcanic province…1 March, 1993 by Roger Worland, William Block
Supercooling points of adults and larvae of the coleopterans Hydromedion sparsutum and Perimylops antarcticus at South Georgia ranged from -3.0 to -5.4°C with Perimylops freezing at c.1.6°C lower than Hydromedion.…Read more on Ice nucleation studies of two beetles from sub-antarctic South Georgia
1 February, 1993
Growth of upper canine teeth of male Antarctic fur seals (Arctocephalus gazella) which died of natural causes at Bird Island, South Georgia, was quantified from measurements of annual layers in…1 February, 1993 by Roger Worland, William Block
Small polythene tents were used to simulate the effects of climate warming on two contrasting vegetation types (polar semi-desert and tundra heath) at Ny Ålesund, Spitzbergen, Svalbard. Temperature microclimates are…1 February, 1993
The Fossil Bluff Group of south-east Alexander Island contains strata ranging from Kimmeridgian to Albian in age and represents the infill of a fore-arc basin to the west of the…1 February, 1993 by Richard Horne
We demonstrate that geomagnetically trapped ion-cyclotron waves that are generated near the equator with frequencies below ΩHe+, can experience significant O+ cyclotron resonant absorption near the reflection point at frequencies…Read more on Cyclotron absorption of ion-cyclotron waves at the bi-ion frequency
1 February, 1993
The spatial distribution and species composition of high-Antarctic ichthyonekton was investigated during the EPOS 3 cruise by RV Polarstern in the eastern Weddell Sea during January–February 1989. A multiple rectangular…1 January, 1993 by Vsevolod Afanasyev
An activity recorder weighing 24 g with on-board data storage, designed to record data relating to seabird activity and behaviour at sea, is described. The principles, the design specification and…Read more on A miniature storing activity recorder for seabird species
1 January, 1993
In an investigation of the age structure of a population of Notothenia coriiceps Richardson at the South Orkney Islands, Antarctica, the microstructure of otoliths was examined. Progress is reported on…1 January, 1993
Female southern elephant seals, Mirounga leonina, assemble in large groups and each gives birth to a single pup which is nursed for some 3 weeks. Weaning mass is highly variable;…1 January, 1993
Sr-isotope data from the Rubh’an Eireannaich sill, one of a suite of composite (mafic-silicic) minor intrusions associated with the 59 Ma Skye Intrusive Centre, NW Scotland, indicate that both crystal-liquid…1 January, 1993
Tritiated water dilution was used to measure changes in the proximate body composition of adult female southern elephant seals at the end of lactation and at the beginning and end…1 January, 1993 by John King
Data from 16 radiosonde stations are used to study the transport of water vapour in the antarctic atmosphere. Total column moisture (TCM), winds and moisture flux measurements are presented, together…Read more on Atmospheric water-vapour transport to Antarctica inferred from radiosonde data
1 January, 1993 by Andrew Clarke
Climatic change has long been regarded as an important factor in evolutionary history. In particular, periods of enhanced extinction in marine taxa (especially those from warmer waters) have frequently been…Read more on Temperature and extinction in the sea: a physiologist’s view
1 January, 1993 by Peter Convey
We propose four measures of allocation to sexual reproduction in mosses, and apply these to data obtained from 15 species found fruiting on Signy Island, South Orkney Islands, in the…Read more on Investment in sexual reproduction by Antarctic mosses
1 January, 1993 by Hugh Corr, Keith Nicholls
Measurements of radar echo strength have been carried out on Ronne and George VI Ice Shelves, Antarctica. The differences in ice-column absorption between the two sites cannot be resolved by…Read more on Radar absorption due to impurities in Antarctic ice
1 January, 1993 by Alistair Crame
The Byers Group, exposed on Byers Peninsula, western Livingston Island, Antarctica, comprises a mudstone dominated sequence at least 1 km thick which accumulated in a marginal fore-arc environment. The basal,…1 January, 1993
The pattern and characteristics of diving in two female macaroni penguins Eudyptes chrysolophus was studied, during the brooding period, using continuous-recording time-depth recorders, for a total of I8 days (15…Read more on Diving pattern and performance in the macaroni penguinEudptes chrysolophus
1 January, 1993
Isotope and chemical analyses of the GRIP ice core from Summit, central Greenland, reveal that climate in Greenland during the last interglacial period was characterized by a series of severe…Read more on Climate instability during the last interglacial period recorded in the GRIP ice core
1 January, 1993
1 The carbon and nitrogen dynamics in a maritime Antarctic lake outflow stream were investigated. The stream and the algal communities could be split into two zones: a semi-aquatic margin consisting…Read more on Carbon and nitrogen dynamics in a maritime Antarctic stream
1 January, 1993
Small ponds and puddles are extremely common throughout the ice-free areas of the maritime Antarctic. The carbon and nitrogen dynamics in a typical pond on Livingston Island, South Shetland Islands…Read more on Carbon and nitrogen dynamics in a small pond in the maritime Antarctic
1 January, 1993
1. The causes of variations in the composition of microalgal communities on frost-sorted soil polygons on Signy Island, maritime Antarctica, were investigated, based on analyses of physical and chemical conditions…1 January, 1993
The Mesozoic forearc of Alexander Island, Antarctica, is one of the few places in the world where the original stratigraphic relationship between a forearc basin and an accretionary complex is…1 January, 1993
Mass accumulations of belemnite rostra (‘belemnite battlefields’) are common in Mesozoic sediments, and accumulations of belemnoids are also known from older rocks. Many Recent teuthid species suffer mortality immediately after…1 January, 1993
Within the stable political context of the Antarctic Treaty regime, science has flourished, achieving considerable prominence and an increasing global relevance. Issues such as stratospheric ozone depletion and enhanced ultraviolet…1 January, 1993
Antarctica is probably the least known of the world's regions. Intensive research by over 20 nations during the past 30 years has demonstrated increasingly the integral and often critical role…1 January, 1993
The nature of the coupling between the solar wind and magnetosphere on the dayside of the Earth, and the response of the ionosphere to this coupling are currently topics of…1 January, 1993
On South Georgia, two recently introduced species of predatory beetle,Oopterus soledadinus andTrechisibus antarcticus (Coleoptera, Carabidae), were studied in the period November 1991–April 1992. The study area comprised the coastal area…1 January, 1993
A series of observations, using a dual-frequency calibrated echosounder operating at 38 and 120 kHz, of a patch of Euphausia superba close to South Georgia in 1986 is described. Sea…1 January, 1993
Seventeen species of decapod crustaceans have been described from Campanian through Paleocene rocks in the Santa Marta, López de Bertodano, and Sobral Formations of the James Ross Basin, Antarctica. Of…1 January, 1993
Satellite radar interferometry (SRI) provides a sensitive means of monitoring the flow velocities and grounding-line positions of ice streams, which are indicators of response of the ice sheets to climatic…1 January, 1993
Rock moisture content was determined for rock samples on different aspects of rock outcrops on Livingston Island during a summer season. As a result of the dominant rainbearing northerly winds…1 January, 1993
A stock of biotite-muscovite-garnet leucogranite crops out in the lower course of Río Cisnes as an unusual minor lithology within the predominantly dioritic to tonalitic North Patagonian Batholith. Foliated and…Read more on Granite generation and rapid unroofing related to strike-slip faulting, Aysén, Chile
1 January, 1993 by Richard Hindmarsh, Richard Hindmarsh
Although the mechanics and qualitative dynamics of grounded ice sheets and ice shelves are fairly well understood, this is not true for the transition between the two. In consequence, the…1 January, 1993
Because the northern elephant seal (Mirounga angustirostrus) was heavily exploited during the 19th century, it experienced an extreme population bottleneck. Since then, under legislative protection in the United States and…1 January, 1993
Miocene-Recent continental alkalic basalts were erupted along the Antarctic Peninsula as a result of decompressional melting of the asthenosphere caused by the formation of slab-windows beneath the continental margin following…1 January, 1993 by Robert Larter
On the basis of multichannel seismic reflection, magnetics and bathymetry data, a Pleistocene-Holocene (1 January, 1993 by Richard Horne
The propagation, growth and absorption of electromagnetic ion cyclotron waves in the Pc 1 frequency range is investigated using the HOTRAY ray tracing program for a realistic distribution of thermal…1 January, 1993
The Antarctic Peninsula region has exprienced a long-term warming trend over the twentieth century, with the 1971-90 mean at Faraday being 1.9°C warmer than the mean over 1903-41 based on…1 January, 1993 by Robert Larter
The outer shelf on the Antarctic Peninsula Pacific margin south of 63°30′S is underlain by Pliocene-Pleistocene prograding sequences which have been produced mainly by the action of ice sheets grounded…1 January, 1993
The question is posed: "what limits the presence, distribution, and abundance of life in Antarctica?" Traditionally, continental isolation has been considered to restrict the arrival of new species and extreme…1 January, 1993 by Ed King
An alternative seismic source was investigated in an experiment conducted near Rothera Station, Antarctic Peninsula. The source was an airgun fired above the snow surface. Comparison shots using explosive and…Read more on Seismic characteristics of an airgun fired over snow
1 January, 1993 by John King
Simple models are used to assess the factors controlling near-surface winds over an Antarctic ice shelf. Observations from Halley Station and an automatic weather station situated close to the coastal…Read more on Control of near-surface winds over an Antarctic ice shelf
1 January, 1993
We analyze ionospheric convection patterns over the polar regions during the passage of an interplanetary magnetic cloud on January 14, 1988, when the interplanetary magnetic field (IMF) rotated slowly in…1 January, 1993
The effect of maternal age and condition on the date of parturition and the duration of the perinatal period of Antarctic fur seals at Bird Island, South Georgia, were investigated…1 January, 1993
Geosat radar altimetry defines a pattern of closely spaced curvilinear gravity anomalies in the northern Weddell Sea and adjacent parts of the southwest Atlantic. These anomalies are caused by a…Read more on Seafloor spreading in the Weddell Sea and southwest Atlantic since the Late Cretaceous
1 January, 1993
Larval fish assemblages are considered within the context of the unique ichthyofauna which evolved in Antarctic waters as a result of environmental cooling, glaciation, and isolation by the Antarctic polar…1 January, 1993
We studied the influence of sex of pup, maternal age, birth date of pup, number of foraging trips, and the mean duration of foraging trips at sea and nursing visits…1 January, 1993 by Eugene Murphy
A visual classification was carried out of echo trace characteristics derived from 113 integration intervals of 1 n mi (nautical mile) each taken from the Southern Ocean in the area…1 January, 1993
The distributional features and physical characteristics of 4830 krill (Euphausia superba Dana) aggregations detected acoustically in the Southwest Atlantic between 26 January and 21 February 1981 are described. Results are…1 January, 1993 by Peter Ward
The ability to acoustically separate zooplankton species is an important requirement for ecological studies and to improve biomass estimates. In order to distinguish between Euphausia superba and other swarm-forming macroplankters…1 January, 1993
A new method for high-resolution (3 mm) dielectric profiling of ice cores is described. The method measures the capacitance and conductance of the ice at a single frequency (chosen to…Read more on High-resolution dielectric profiling of ice cores
1 January, 1993
Annual survival of breeding female Sparrowhawks Accipiter nisus was estimated by a capture-recapture procedure in three different areas, Eskdale and Annandale in southern Scotland and Rockingham Forest in east-central England.…Read more on Annual survival of Sparrowhawks Accipiter nisus breeding in three areas of Britain
1 January, 1993 by Keith Nicholls
Two vertical ice temperature profiles from locations in the Antarctic Peninsula unaffected by meltwater are presented. A simple time-dependent heat diffusion-advection model is used to infer broad surface temperature variations…Read more on Extending the Antarctic meteorological record using ice-sheet temperature profiles
1 January, 1993 by Andrew Clarke
The growth rate of the infaunal nuculanid bivalve Yoldia eightsi at Factory Cove, Signy Island, South Orkney Islands (maritime Antarctica), was estimated from internal shell increments and 45Ca incorporation of…1 January, 1993
Thelidium austroatlanticum sp. nov. is described from Signy island; it is characterized by an epilithic thallus, more or less appressed involucrellum, and 1-septate spores 30–40 μm long. Thelidium incavatum is…1 January, 1993 by Peter Ward
The natural diets of adult female Euchaeta antarctica, E. farrani, E. rasa and E. biloba, as well as male and female copepod stage V E. antarctica, were compared through gut…Read more on Summer and winter diet of four carnivorous copepod species around South Georgia
1 January, 1993 by Lloyd Peck
The punctate brachiopods Liothyrella neozelanica and Neothyris lenticularis were compared with the impunctate Notosaria nigricans and the bivalve molluscs Mytilus edulis and Lima colorata in terms of the force needed…Read more on The tissues of articulate brachiopods and their value to predators
1 January, 1993
The simple technique of point counting is very quick and is suitable for shipboard use, or in any study where high accuracy is not necessary. Point-counting smear slides yields results…1 January, 1993
The records, taxonomy and geographical distribution of 528 species of Acari collected from the Antarctic, sub-Antarctic islands and the Southern Ocean are collated. Included are free-living and phoretic mites, parasites…1 January, 1993
Nine species of marine littoral Halacaridae were collected from Husvik Harbour, South Georgia, all of which are new to the fauna of the island. These include Isobactrus microdens Newell, Rhombognathus…1 January, 1993
Terrestrial sedimentary rocks at Hope Bay, northern Graham Land are well known for their diverse but poorly-preserved fossil flora, previously assigned ages ranging from Early Jurassic-Early Cretaceous. The beds form…1 January, 1993
The Caytoniales are represented in the Early Jurassic floras from Hope Bay and Botany Bay, Antarctica, as completeleaves and detached leaflets (Sagenopteris) together with microsporophylls (Caytonanthus). Systematic sampling at Botany…Read more on Caytoniales in Early Jurassic floras from Antarctica
1 January, 1993
Antarctic plankton community respiration rates were determined from in vitro changes in dissolved oxygen. Oxygen consumption rates, measured at in situ temperatures between 0 and 6°C, were found to lie…Read more on Temperature and Antarctic plankton community respiration