Found 14065 items
1 August, 1993 by Mark Clilverd
Whistler mode signals from VLF transmitters received at Faraday, Antarctica (65° S, 64° W) during 1986–1991 show an annual variation in the number of hours over which signals are observed,…1 August, 1993 by Eric Wolff
Surface snow samples have been analysed for the heavy metals Cd, Cu, Pb and Zn to investigate the spatial scale of local sources of pollution in Antarctica. Samples from around…Read more on The local deposition of heavy metal emissions from point sources in Antarctica
1 July, 1993
New Rb-Sr and K-Ar geochronological data are presented for the majority of known pre-Cenozoic outcrops in Thurston Island, the Jones Mountains, and the western Eights Coast, which collectively represent the…Read more on The Pre-Cenozoic magmatic history of the Thurston Island Crustal Block, west Antarctica
1 July, 1993 by John Turner, Thomas Lachlan-Cope
The mesoscale (less than 100km) vortices occurring in the two polar regions are considered in terms of their geographical and seasonal distribution, satellite cloud signatures and forcing mechanisms. Environmental conditions…Read more on A comparison of Arctic and Antarctic mesoscale vortices
1 June, 1993
Satellite infra-red imagery and meteorological data suggest the presence of winter open water (polynya) in the coastal pack ice to the north and west of the Brunt Ice Shelf. Satellite…Read more on Evidence for an Antarctic winter coastal polynya
1 June, 1993 by Andrew Clarke
Egg volume and several aspects of egg nutrient content (dry mass, organic content, carbon and nitrogen content) were measured in eggs from five species of polar caridean shrimp (Crustacea; Decapoda):…Read more on Egg size and egg composition in polar shrimps (Caridea; Decapoda)
1 June, 1993
We compare the microwave and low-frequency (LF) dielectric conductivity of natural and artificial ice as a function of impurity concentration and temperature. We find a linear dependence of conductivity on…1 June, 1993 by Lloyd Peck
Embryonic and larval development were followed from fertilisation to settlement in the Antarctic heteronemertean Parborlasia corrugatus (McIntosh, 1876). The first cleavage occurred 10 to 15 h after fertilisation, and the…1 June, 1993 by Paul Rodhouse
Regurgitations were collected from 41 black-browed albatross adults feeding chicks at Bird Island (54°S 38°W), South Georgia in February 1986. The samples were sorted into recognisable food categories and weighed.…Read more on Cephalopod prey of the black-browed albatrossDiomedea melanophrys at South Georgia
1 May, 1993 by Alistair Crame
Our concept of polar marine faunas as having evolved in comparative isolation over long periods may need to be revised. New evidence from the Southern Ocean, in particular, suggests that…Read more on Latitudinal range fluctuations in the marine realm through geological time
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
Plus CD-ROM. Copyright © Scientific Committee on Antarctic Research 1993Read more on Antarctic digital database user’s guide and reference manual (v1.0)
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
Microbial and enzymatic activities were measured during the 49-day austral summer of 1991 in two fellfield soil polygons (WW-5 and WW-18) at Signy I. In 0-2.5 cm cores, microbial counts…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…