Showing 11862 items
1 November, 1991
Nitrogen assimilation was measured in two austral summers in the Scotia Sea around the island of South Georgia as well as the Bransfield Strait. Nitrate and ammonium assimilation was measured…29 October, 1991 by John Turner
1 October, 1991
We observed 195 multispecies feeding flocks of birds near Bird Island, South Georgia, between 4 February and 5 March in 1986. Up to 19 seabird species plus Antarctic fur seals…Read more on Observations of multispecies seabird flocks around South Georgia
1 October, 1991
During three days of quiet geomagnetic conditions in August 1988, both the EISCAT UHF radar and the NOAA digital ionospheric sounder (Dynasonde) were operated from 12:00 to 22:00 U.T. Sporadic-E…1 September, 1991
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…Read more on Hydrocarbons in the Antarctic marine environment
1 September, 1991
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.…Read more on The spatial distribution of microalgae on Antarctic fellfield soils
1 September, 1991
During the austral summer of 1987/1988, three 24 h in situ primary productivity measurements were made at a nearshore sublittoral site on the east coast of Signy Island, Antarctica. The…1 September, 1991
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…Read more on Freshwater stream ecosystems of James Ross Island, Antarctica
1 September, 1991
A 100‐m ice core from site G 15 (accumulation rate 0.1 m water yr−1, mean annual temperature −38°C) on the Mizuho plateau, Dronning Maud Land, East Antarctica, has been analysed…Read more on A continuous 770-year record of volcanic activity from east Antarctica
1 September, 1991
The Antarctic fellfield habitat is an extreme terrestrial environment in which the survival of organisms depends upon an ability to withstand both very low temperatures and severe water shortage. The…Read more on Water-loss and anhydrobiotic survival in nematodes of Antarctic fellfields
1 September, 1991
We have used observations of the group time delay and Doppler shift of ducted VLF whistler mode signals propagating near L = 2.5 to deduce the azimuthal component of the…Read more on Electric fields at L = 2.5 during geomagnetically disturbed conditions
1 September, 1991
Little is known about the aerial transport of microbes, plants and animals into and between Antarctic terrestrial and freshwater habitats. Isolation by the circumpolar Southern Ocean restricts propagules to three…Read more on Aerobiology and colonization in Antarctica — the BIOTAS Programme
1 August, 1991
A time-depth-temperature recorder provided a continuous record of diving by a female southern elephant seal in relation to water temperature for 27 days (1939 dives) after completion of moult. Mean…1 July, 1991
A model of the dynamics of magnetic storms is proposed which describes the effects of magnetospheric activity on irregularities at F layer heights for auroral and subauroral latitudes. For high…1 July, 1991
Aerosol samples were collected at a remote site near the east coast of the Antarctic Peninsula during the austral summer of 1984/85. Filter samples were analyzed for Al (as a…Read more on Concentrations and sources of metals in the Antarctic Peninsula aerosol
1 July, 1991
The seasonal pattern of the microphytobenthic community at a near-shore site on the east coast of Signy Island (60°43′S, 45°38′W), South Orkney Islands, was examined over a period of 18…1 July, 1991
A sediment core from Jane Basin, northern Weddell Sea, contains distinct bands, up to 3 cm thick, of well preserved diatom frustules, contrasting with the generally poor preservation of adjacent…Read more on Unusual diatom layers in upper pleistocene sediments from the northern Weddell Sea
1 July, 1991
The results are presented of a statistical study of the occurrence, strength, frequency and polarization characteristics of magnetic pulsations in the Pc3 frequency range (0.022–0.1 Hz) recorded at Halley, L…Read more on On the nature of Pc3 pulsations at L = 4 and their solar wind dependence
1 July, 1991 by Mark Clilverd
Whistler mode group delays observed at Faraday, Antarctica (65°S, 64°W) decrease after the onset of magnetic storms, and slowly recover to normal levels in 1 or 2 days. This is…Read more on Magnetic storm effects on the mid-latitude plasmasphere
1 June, 1991
(1) We investigated time allocation to parental care ashore and foraging at sea by lactating Antarctic fur seals at Bird Island, South Georgia, during 1988-89 and 1989-90 and related this…Read more on Time budgets and foraging characteristics of lactating Antarctic fur seals
1 June, 1991
A study has been made of vertical thermospheric winds in the vicinity of Halley, Antarctica (75.5°S, 26.8°W; L = 4.2). Strong downward winds, up to 50 m s−1, are frequently…Read more on Vertical thermospheric winds at the equatorward edge of the auroral oval
1 June, 1991
Ridge crest-trench interactions along continental destructive plate margins may result in the development of slab-free windows beneath the continental margin. Slab windows were generated at various locations along the Pacific…Read more on Relation between alkalic volcanism and slab-window formation
1 June, 1991 by Andrew Clarke, Peter Ward
Resting metabolic rate(V ˙ O 2[rest] ) (V˙O2[rest]) was measured in demersal stages of the teleostNotothenia neglecta Nybelin from the South Orkney Islands, Antarctica, from 1985 to 1987. The relationship…1 June, 1991 by Ed King
The British Antarctic Survey has commenced a programme of multichannel seismic reflection work over the Antarctic continental ice sheet and surrounding ice shelves. This is part of an integrated geophysical…Read more on Effectiveness of different shooting techniques in Antarctic firn
1 June, 1991 by Alistair Crame
An important new section for the latest Cretaceous marine sedimentary record is described from Cape Lamb, Vega Island, Antarctica. Some 480 m thick, it has been divided into three lithostratigraphic…Read more on Late Cretaceous stratigraphy and sedimentology of Cape Lamb, Vega Island, Antarctica
1 June, 1991
A discussion of the cross-spectral properties of eddies in the lowest 40 m of the nocturnal boundary layer is presented. The study involves the analysis of meteorological data collected by…Read more on On the characteristics of eddies in the stable atmospheric boundary layer
1 June, 1991
A model of the terrestrial plasmasphere that includes an eccentric dipole geomagnetic field has been developed. Calculations are carried out for tubes of plasma at the longitude of Argentine Islands,…1 June, 1991 by Howard Roscoe
Measurements of N2O5 in the stratosphere and of its spectrum at 1240 cm−1 in the laboratory are reviewed. Errors in previous publications about N2O5 are discussed briefly. The earliest stratospheric…Read more on Review and revision of measurements of stratospheric N2O5
1 June, 1991
In the gentoo penguin, Pygoscelis papua, we examined the effects of intra-clutch egg size differences and hatching asynchrony on differential chick growth and survival (including post-fledging survival), in five years…1 June, 1991 by Eric Wolff, Robert Mulvaney
Heterogeneous chemistry producing active chlorine has been identified as crucial to Antarctic ozone depletion. Most attention has focussed on reactions on solid polar stratospheric cloud (PSC) particles, although there is…1 May, 1991
The reproductive pattern of pinnipeds is characterised by embryonic diapause, annual reproduction, and synchronous breeding cycles. Active gestation lasts about 8 months in most species, but the duration of embryonic…1 May, 1991
We review theoretical and numerical studies of VLF triggered emissions generated by manmade signals propagating in the whistler mode in the magnetosphere. Instead of listing all the past studies on…Read more on A review of observational, theoretical and numerical studies of VLF triggered emissions
1 April, 1991
Ground‐based measurements of stratospheric slant column NO2 amounts made at Halley Bay, Antarctica in 1987 are compared with ozone and temperature profiles from balloon‐borne sondes. Sunrise‐to‐sunset (am/pm) ratios of NO2…Read more on NO2 overnight decay and layer height at Halley Bay, Antarctica
1 April, 1991
Comparison of the size, shape and shell morphology in littoral and sub-littoral morphs of the Antarctic limpet Nacella concinna reveal differences in shell morphology which are enhanced by structural anomalies…1 March, 1991
The first observations of the signatures of Pc1 pulsations in ionosonde echo data are reported. Oscillations are frequently observed in Doppler velocity, echo amplitude, group range and skymap echo-location position,…1 March, 1991
Progesterone in Antarctic fur seals was undectable from 1–2 days before parturition to 4–6 days after parturition. There was a rapid increase in progesterone to 20 ng/ml between 6 and…1 March, 1991 by David Vaughan
THE breaking up of ice shelves around the Antarctic Peninsula has been cited1 as a “sign that a dangerous warming is beginning in Antarctica”. Here we present satellite images showing…Read more on Rapid disintegration of the Wordie Ice Shelf in response to atmospheric warming
1 March, 1991 by Michael Pinnock
Two case studies are presented of the large-scale nightside ionospheric plasma convection observed simultaneously in the two polar regions using HF backscatter radars. The case studies occur during geomagnetically quiet…Read more on Studies of conjugate plasma convection in the vicinity of the Harang discontinuity
1 March, 1991
The bivalve Aulacomyella is described formally from Tithonian deposits of the Antarctic Peninsula region for the first time. Two species are recognized. A. willeyi Kelly sp. nov. was collected in…Read more on The bivalve Aulacomyella from the Early Tithonian (Late Jurassic) of Antarctica
1 March, 1991 by Michael Pinnock
Identifying the causative mechanisms at the magnetopause that produce a variety of transient plasma velocity signatures in the high latitude ionosphere is difficult. Correct identification is of fundamental importance in…1 February, 1991
The life cycles and distribution of three dominant copepods,Calanoides acutus, Calanus simillimus andRhincalanus gigas were studied from the “Discovery” collections in the Scotia Sea earlier this century.C. simillimus is a…1 February, 1991 by Andrew Clarke
Cold adaptation encompasses all those aspects of an organism's physiology that allow it to live in polar regions. With the exception of the special case of the need to avoid…Read more on What is cold adaptation and how should we measure it?
1 February, 1991
Blood chemistry and haematological parameters have been determined in the Antarctic teleosts, Notothenia neglecta Nybelin and Notothenia rossii Richardson at 2° C. Samples were taken using chronically implanted dorsal aortic…1 February, 1991
The apparent polar wander paths (= APWPs) for the northern and southern continents have been redetermined using revised time-scales and data. When plotted on the conventional Pangea, Pangea A, the…1 February, 1991
The breeding biology of the macaroni penguin, Eudyptes chrysolophus, was studied over four years, 1976 and 1986–88, at Bird Island, South Georgia. Birds were migratory, being absent during winter (May…1 January, 1991
The diving pattems of two male and one female Blue-eyed Cormorants Phalacrocorax atriceps were recorded with continuous-recording time-depth recorders for l0-13 days during the 1990 breeding season. For the female…1 January, 1991
A digital ionosonde has been used at Halley (75°31′S, 26°59′W) to examine the fading on time scales of a few seconds of 4.5 MHz signals reflected from sporadic-E ionization. Fourier…Read more on The rapid fading of radio waves reflected from sporadic-E ionization
1 January, 1991
Energy expenditure of fasting territorial male Antarctic fur seals at South Georgia was measured by mass loss and analysis of carcass composition using tritium dilution in 1987 and 1988. Mean…1 January, 1991
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…Read more on Muscle growth in the Antarctic teleost, Notothenia neglecta (Nybelin)
1 January, 1991
The intense magnetic storm of December 19, 1980 occurred during a major rocket and balloon geophysical research campaign at Siple Station, Antarctica. A balloon flight measuring the electric field and…Read more on The intense magnetic storm of December 19, 1980: Observations atL= 4
1 January, 1991
Analyses of a core from the deepest known moss peat bank in Antarctica, on Elephant Island, South Shetlands, show that this Chorisodontium aciphyllum-dominated bank began to grow ca. 5500 14C…1 January, 1991 by John Turner
Analysis of AVHRR data collected during the summer and winter over the Ross Ice Shelf reveals complex patterns of curvilinear stripes. In particular, a large, looping pattern of stripes is…1 January, 1991 by Andrew Clarke
The deep-water prawn Pandalus borealis Kroyer, 1838 was sampled at six locations from Krossfjord, Spitsbergen (79⚬N, close to the known northerly limit of distribution) to Kosterfjord, Sweden (58⚬N, close to…Read more on Egg Size and Reproductive Output in the Deep-Water Prawn Pandalus borealis Kroyer, 1838
1 January, 1991 by Andrew Clarke, Lloyd Peck
The polar marine environment is characterised by low stable temperatures with seasonal variations ranging from ±3°C at lower latitudes to only ±0.2°C at high latitudes. The Arctic basin is dominated…1 January, 1991 by Mark Clilverd
Whistler mode group delays from the VLF Doppler experiment at Faraday, Antarctica (65°S, 64°W) show an annual variation that has a maximum in December and a minimum in June/July. Assuming…1 January, 1991
The pattern and characteristics of diving of two male blue‐eyed shags Phalacrocorax atriceps were studied, using continuous‐recording time‐depth recorders, for a total of 15 consecutive days during which the depth,…Read more on Diving patterns and performance in the Antarctic blue-eyed shag Phalacrocorax atriceps
1 January, 1991
The attachment to artificial substrata (carborundum paper) of cyanobacteria and algae isolated from Antarctic fellfield soils was investigated using a simulated flow apparatus. Generally, the rugosity of the substratum was…1 January, 1991
The survival and growth of four genera of cyanobacteria and microalgae isolated from Antarctic fellfield soils were investigated. Survival of freezing and desiccation were studied by vital staining, and the…Read more on Effects of physical factors on the survival and growth of antarctic terrestrial algae
1 January, 1991
Investigation of the seasonal changes in composition of an immature Antarctic fellfield cyanobacterial/microalgal community has demonstrated a repeated periodicity. The community consisted of only 14 species. Early spring growth of…Read more on The seasonal periodicity of algae on Antarctic fellfield soils
1 January, 1991 by John Turner
Seasat's contributions to ice sheet glaciology are explored with emphasis on the experience gained from this mission and on how this has assisted in defining future satellite missions. The sensors…Read more on The contribution of Seasat to ice sheet glaciology
1 January, 1991
1. Plasma metabolites and nutrients of macaroni penguins (Eudyptes chrysolophus) arriving on land in good condition, following intense feeding, for breeding and moulting were investigated. 2. The pre-breeding female birds…1 January, 1991 by Adrian Jenkins
Detailed glaciological studies have been completed at 28 sites lying on an approximate flow line, extending 760 km across Ronne Ice Shelf. Parameters measured at each location include ice velocity,…Read more on Ice-ocean interaction on Ronne Ice Shelf, Antarctica
1 January, 1991 by William Block
Live and dead specimens of the Antarctic collembolan Cryptopygus antarcticus (Willem) dry, under constant external conditions of temperature (25 or 35°C) and r.h. (0%), like most hygric soil arthropods. The…Read more on Drying processes in the Antarctic collembolan Cryptopygus antarcticus (Willem)
1 January, 1991
Samples of Loligo gahi (D'Orbigny) were collected from commercial fishing vessels in the Falkland Islands Interim Conservation and Management Zone (FICZ) between March and October 1987, and from the R/V…Read more on Post-recruit growth of the Patagonian squid Loligo gahi (d’Orbigny)
1 January, 1991
Sundström (1986) erected the genus Proboscia for solenoid diatoms whose valves tapered to a proboscis, but only assigned one species to it, the boreal Rhizosolenia alata Brightwell. We have found…1 January, 1991
Five fossil species of Rhizosolenia are known only from the distal parts of the valve. The resemblance of these tubular structures to the proboscis of the modern genus Proboscia Sundström,…1 January, 1991
During winter 1989 at South Georgia, gentoo penguins showed a very rapid change in diet over a 10-day period. On 11-12 July, food samples were of low masses (150g) and…1 January, 1991 by John King
1 January, 1991
THE tectonic fabric of the sea floor created at spreading ridges generally curves in the direction of ridge offset near transform faults, owing to the influence of shearing stress on…Read more on Unusual sea-floor fabric near the Bullard fracture zone imaged by GLORIA sidescan sonar
1 January, 1991
Different environmental conditions, particularly daylength and intensity of natural light, may influence the ability of shiftworkers to adapt to the abrupt phase-shifts of 24 h time cues imposed by the…1 January, 1991
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…Read more on The cryptostigmatid mite Halozetes belgicae (Michael) in the maritime Antarctic
1 January, 1991
The dielectric profiling (DEP) technique is described and some of the differences between it and standard electrical tools used in ice core analysis are discussed. The results of DEP analysis…Read more on Application of the dielectric profiling technique to ice core studies
1 January, 1991
Early diagenetic (precompactional) concretions are abundant throughout the Cretaceous-Tertiary Marambio Group Larsen Basin, Antarctica. Four distinct concretion types are recognised: (1) spherical-subspherical concretions: (2) sheet concretions; (3) fossil-nucleated concretions; and…1 January, 1991
The polar regions are unique laboratories for carrying out research on both the atmosphere and the near-Earth space environment. The relatively undisturbed conditions help us explore phenomena like the greenhouse…Read more on Atmospheric and space research from polar regions
1 January, 1991
Whistler activity at L ≃ 4 is known to be a function of longitude, peaking in the Weddell Sea sector of Antarctica; a combination of source and propagation factors, the…1 January, 1991
Eight isolates of bacteria from the soils of maritime Antarctica and Antarctic peninsula have been identified as members of the genus Janthinobacterium. Based on their morphology, physiological characteristics, biochemical characteristics…1 January, 1991 by Andy Smith
New tiltmeter data are presented from Doake Ice Rumples on Ronne Ice Shelf, Antarctica. Five sites which showed a tidal ice-shelf flexure have been analysed using an elastic beam model…Read more on The use of tiltmeters to study the dynamics of Antarctic ice-shelf grounding lines
1 January, 1991
Six species of Stereocaulon and one unnamed taxon (close to S. glabrum) are reported from South Georgia, the maritime Antarctic islands and Antarctic Peninsula. S. caespitosum is new to the…Read more on The lichen genus Stereocaulon in Antarctica and South Georgia
1 January, 1991
The Advanced Ionospheric Sounder at Halley (75° 31′S, 26° 59′W) in Antarctica has been used to observe the F-region disturbance caused by an atmospheric gravity wave. Observations at 4.5 MHz…Read more on Compression and rarefaction of F-region plasma caused by an atmospheric gravity wave