Found 14089 items
1 June, 1996 by Philip Leat
At Mount Charity, north-eastern Palmer Land, Rb–Sr whole-rock dating has identified three successive phases of granitoid emplacement in Triassic (232 ± 4 Ma), Jurassic (168 ± 1 Ma), and Cretaceous…1 May, 1996
The coastal sea ice in the vicinity of Davis Station, Antarctica (68* 35' S, 77* 58' E), supported a diverse microbial community which varied in composition and biomass in response…1 May, 1996
A previously reported porphyry Cu + Mo deposit in an Eocene pluton within the South Shetland Island magmatic arc has been re-interpreted as three distinct hydrothermal assemblages. The oldest assemblage…1 May, 1996 by David Barnes, Lloyd Peck
Prevalence (proportion of host organisms covered) and cover of encrusting epibiota were investigated for four Antarctic and two New Zealand species of deep-sea brachiopods. All epibiota was identified to the…1 May, 1996
Sediment profiles from several lakes/ponds in the northern, ice-free area of James Ross Island, Antarctica, were the subject of a multi-disciplinary palaeoenvironmental investigation. The results, obtained from lithological, geomagnetic, geochemical…1 May, 1996 by Andrew Clarke
There are few instances where a knowledge of the thermal physiology, habitats and lifestyles of a group of closely related species can be mapped onto a well-supported phylogeny and a…Read more on Evolution and adaptive radiation of antarctic fishes
1 May, 1996
The North Scotia Ridge controls the eastward and northward flow of the Antarctic Circumpolar Current (ACC) emerging from Drake Passage. Existing physical oceanographic data in this region are sparse and…1 May, 1996 by Eric Wolff, Robert Mulvaney
Dimethyl sulfide, methane sulfonate, non-sea-salt sulfate and sulfur dioxide concentrations in air were obtained during a cruise between the U.K. and the Antarctic during the period October 1992–January 1993. In…1 May, 1996 by Adrian Jenkins
The first oceanographic measurements across a deep channel beneath the calving front of Pine Island Glacier reveal a sub-ice circulation driven by basal melting of 10–12 m yr−1. A salt…Read more on Antarctic ice sheet melting in the southeast Pacific
1 May, 1996 by Eugene Murphy, Philip Trathan
To investigate the role of sea ice cover on penguin populations we used principal component analysis to compare population variables of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins breeding…1 May, 1996
Southern elephant seals spend two periods on land each year, during breeding and moult, exposed to intensive UV radiation. The time between periods on land are spent at sea, with…1 April, 1996
Within the Albian Fossil Bluff Group of Alexander Island, Antarctica, sheet flood deposits have preserved palaeosols within situfernsAlamatus bifariusDouglas andAculea acicularissp. nov. Reconstructed as upright ferns, with fronds arising from…1 April, 1996
Seven species of angiospermous leaves from the mid to Late Albian of Alexander Island, Antarctica provide further evidence of angiosperm radiation into high southern palaeolatitudes. The leaves have both palmate…1 April, 1996 by Peter Convey, William Block
As an addendum to a recent publication on the terrestrial arthropod fauna of the Byers Peninsula Site of Special Scientific Interest (SSSI), which included preliminary identification of four Collembola, we…1 April, 1996
When fish are patchily distributed, unstratified trawl surveys give highly variable abundance estimates. If the patches are small and mobile, it is impractical to use pre-stratified or multi-stage adaptive designs…Read more on A combined acoustic and trawl survey for efficiently estimating fish abundance
1 April, 1996
Waveforms computed using the new whistler model derived from Maxwell's equations were analysed. In the calculations, realistic model values for magnetospheric parameters were used. The results accurately described whistler-mode propagation…Read more on Whistler-mode propagation: results of model calculations for an inhomogeneous plasma
1 April, 1996
Wild-caught female harbor seals (Phoca vitulina) were classified as sexually mature or immature on the basis of standard body length (< 125 cm immature, > 125 cm mature) and plasma…1 April, 1996
The dynamics of bacterioplankton and protozooplankton in two maritime Antarctic lakes (Heywood Lake and Sombre Lake, Signy Island, South Orkneys) were studied during the phase of ice break-out (December and…Read more on Microbial dynamics during the summer ice-loss phase in maritime Antarctic lakes
1 April, 1996
We have studied a hydromagnetic wave event in the early noon sector of the cusp region, using HF radar data collected in the southern hemisphere and ground-based magnetic data from…Read more on Conjugate cusp-region ULF pulsation responses to the solar wind event of May 23, 1989
1 April, 1996
The application of a two-frequency algorithm to the in situ estimation of large zooplankton is explored in an effort to use information from more than one acoustic frequency. To accomplish…1 April, 1996
The moss Drepanocladus uncinatus (Hedw.) Warnst., from coastal freshwater habitats on the sub-Antarctic island of South Georgia harbours two species of hemi-edaphic oribatid mite namely Edwardzetes elongatus Wallwork (Ceratozetidae) and…1 April, 1996 by Jonathan Watkins
A commercial data-visualization package, AVS, and database are used as the basis for a powerful and highly flexible acoustic data analysis system. The system is easy to use and can…Read more on A visualization-based post-processing system for analysis of acoustic data
1 April, 1996
Data collected between 1926 and 1990, during the Discovery Investigations and fourteen subsequent cruises, have allowed the description of spatial and temporal variability of temperature, salinity, phosphate, silicate, nitrate and…1 March, 1996 by David Barnes
Over 4000 bryozoan-bryozoan interactions were recorded from a total of 985 rocks from six locations at Signy Island in the maritime Antarctic. The majority of these interactions were interspecific ings.…1 March, 1996 by Andrew Clarke, David Barnes
A total of 985 rocks with a wide range of surface areas were examined from six locations at Signy Island in the maritime Antarctic. The shallowest site was intertidal and…1 March, 1996
The pattern of prey distribution can profoundly affect the foraging behavior and success of a predator. In pelagic marine ecosystems, where prey is often patchily distributed, predators must be able…Read more on Temporal scales of foraging in a marine predator
1 March, 1996
The Byers Group, exposed on Byers Peninsula, Livingston Island and Snow Island, Antarctica, is a mudstone-dominated sequence deposited in a fore-arc setting. Palynological studies on parts of the Byers Group…1 March, 1996 by John King
The seasonal and spatial variation of downward longwave radiation (L↓) at the surface of the Antarctic ice sheet is studied using data from four stations. L↓ is found to depend…1 March, 1996
The activity and behaviour of a free-living Antarctic fish,Notothenia coriiceps Richardson (formerlyN. neglecta), was investigated using a high-sensitivity, underwater TV camera at Signy Island, South Orkney Islands. Detailed observations of…Read more on Locomotory activity and behaviour of the Antarctic teleostNotothenia coriiceps
1 March, 1996
In 1991 Chamsocephalus gunnari1 March, 1996 by Richard Horne
Using the HOTRAY code, we demonstrate that lightning-generated whistlers which enter the magnetosphere over a broad range of latitudes (Δλ ≈ 5°) just inside the plasmapause are strongly focused by…Read more on Whistler absorption and electron heating near the plasmapause
1 March, 1996
There is increasing evidence of climate change in Antarctica, especially elevated temperature and ultraviolet B (UVB) flux within the ozone “hole.” Its origins are debatable, but the effects on ice…Read more on Response of pioneer soil microalgal colonists to environmental change in Antarctica
1 February, 1996
The body composition, milk consumption, and growth efficiency of Antarctic fur seal (Arctocephalus gazella) pups were measured over three consecutive lactation periods (1990–1992) at Bird Island, South Georgia. The body…1 February, 1996
The duration of 506 pregnancies in Antarctic fur seals (Arctocephalus gazelld) was measured 1983–1993. On average, pregnancy lasted 359 days, with a range of 340–390 days, representing 20% of the…1 February, 1996
The Diptera are one of the dominant insect consumer groups on sub-Antarctic islands and are thought to contribute significantly to terrestrial ecological processes at many of these islands. The life-cycle…1 February, 1996 by Mark Clilverd, Richard Horne
We report the results of the first multisite campaign using VLF Doppler receivers to detect whistler mode signals in the south Atlantic originating from VLF transmitters in the northern hemisphere.…1 February, 1996 by Roger Worland, William Block
An experiment was conducted to measure the effects of summer warming on the total population densities of soil-dwelling microarthropods in the high Arctic and to compare these results with those…1 February, 1996 by Lloyd Peck
The effect of feeding on metabolism (specific dynamic action; SDA) was assessed in the articulate brachiopod Liothyrella uva (Broderip, 1833) at Signy Island, Antarctica. The response was low and on…1 February, 1996
The diet of lactating female Antarctic fur sealsArctocephalus gazella at South Georgia was investigated during the pup-rearing period (January/March) of 1991–1994. Antarctic krillEuphausia superba was the main prey item, occurring…1 January, 1996 by Paul Rodhouse
The diet of king penguins, Aptenodytes patagonicus, rearing chicks was studied during three consecutive austral winters (1990, 1991 and 1992) at Crozet Islands. The mean stomach content mass of the…1 January, 1996 by Vsevolod Afanasyev
We discuss examples of complex systems composed of many interacting subsystems. We focus on those systems displaying nontrivial long-range correlations. These include the one-dimensional sequence of base pairs in DNA,…1 January, 1996 by Eugene Murphy, Vsevolod Afanasyev
LéVY flights are a special class of random walks whose step lengths are not constant but rather are chosen from a probability distribution with a power-law tail. Realizations of Lévy…Read more on Lévy flight search patterns of wandering albatrosses
1 January, 1996
We examined the accuracy of hydrogen isotope dilution (tritium and deuterium) as a means of determining total body water (TBW), and hence body composition, by comparison with whole-carcass chemical analysis…1 January, 1996
Copepod feeding rates and food selectivity were measured at an oceanic subantarctic site over 5 d in February 1994. A series of gut fluorescence and gut evacuation experiments was carried…1 January, 1996 by John Turner
A case of midtropospheric mesoscale cyclone formation and downward development adjacent to and over the Ross Ice Shelf, Antarctica during May 1988 is presented. This event involved atmospheric phenomena over…Read more on A downward developing mesoscale cyclone over the Ross Ice Shelf during Winter
1 January, 1996 by John King
We examine simulations of the surface mass balance of the sector of the East Antarctic Ice Sheet between 2.4°W and 110.5°E as produced by the United Kingdom Meteorological Office Unified…Read more on A modeling and observational study of East Antarctic surface mass balance
1 January, 1996 by Richard Hindmarsh, Richard Hindmarsh
The mechanical configuration of cavities associated with clasts is discussed, and how this affects the water pressure underneath the clast. The range of permissible water pressure is determined by flow…Read more on Cavities and effective pressure between abrading clasts and the bedrock
1 January, 1996 by Roger Worland, William Block
Larvae and isolated fat body cells of the freeze-tolerant Heleomyza borealis (Diptera, Heleomyzidae) were cooled to sub-zero temperatures between -5 and -40°C at 0.1°C min-1 and then rewarmed at the…Read more on Organism survival and cell integrity in a freeze-tolerant insect
1 January, 1996 by Keith Nicholls
Thermistor cables have been deployed at two sites beneath Ronne Ice Shelf, Antarctica. One site is to the east of a submarine ridge that delineates the eastern boundary of the…Read more on Temperature variability beneath Ronne Ice Shelf, Antarctica, from thermistor cables
1 January, 1996
A comprehensive survey of data on ‘Polar Mesosphere Summer Echoes’, observed by the EISCAT VHF radar during 1988–1993, confirms that (1) these echoes are a summer phenomenon, with a season…Read more on A statistical study of polar mesosphere summer echoes observed by EISCAT
1 January, 1996
In Patagonia a Triassic-Early Jurassic Cordilleran interior magmatic belt preceded the widespread eruption of Middle Jurassic syn-extensional rhyolites. Two plutons (La Calandria and La Leona) represent the easternmost plutonic rocks…Read more on Monzonite suites: the innermost Cordilleran plutonism of Patagonia
1 January, 1996
An experimental study of the fracture mechanics and rheology of ice from the Ronne Ice Shelf, Antarctica, is currently being undertaken. The apparent critical stress-intensity factor (or apparent fracture toughness,…Read more on Experimental fracture and mechanical properties of Antarctic ice: preliminary results
1 January, 1996
Zircon and apatite fission-track data from the LeMay Group accretionary complex and Fossil Bluff Group fore-arc basin sequence on Alexander Island (Antarctica) record a common regional Cretaceous and Cenozoic thermal…1 January, 1996
The stabilized platforms used in marine and airborne gravimeters behave like damped long‐period pendulums. When subjected to horizontal accelerations they tilt, resulting in gravimeter reading errors. The amount of tilt…Read more on Horizontal acceleration corrections in airborne gravimetry
1 January, 1996 by David Vaughan
IN 1978 Mercer1 discussed the probable effects of climate warming on the Antarctic Ice Sheet, predicting that one sign of a warming trend in this region would be the retreat…Read more on Recent atmospheric warming and retreat of ice shelves on the Antarctic Peninsula
1 January, 1996
Epithermal veins in early Triassic turbidites on Hurd Peninsula are isotopically homogeneous over an area of 13 km × 2 km (mean δ34S = +2.2‰, 1σ= 1.7, n = 65)…1 January, 1996 by Eugene Murphy, Philip Trathan
Additional material is available online through the South Georgia GIS project - http://www.sggis.gov.gs/1 January, 1996 by David Barnes
Observations were made on the diet and distribution of eight species of nudibranchs found in Borge Bay, Signy Island, Antarctica. Specimens from seven sites were examined in situ on four…1 January, 1996 by William Block
Water is an essential part of all living organisms and terrestrial arthropods are no exception. They have to balance water loss and water gain to and from their bodies, often…Read more on Cold or drought – the lesser of two evils for terrestrial arthropods?
1 January, 1996
Many endothermic divers regularly exceed the theoretical limit to the duration of aerobic dives, suggesting that assumptions about either the oxygen storage capacity of tissues or the metabolic rate of…1 January, 1996 by Andrew Clarke, Rachel Clarke
Dragonflies and damselflies (Odonata) are important prey for many small falcons, and the recent expansion of the breeding range of the Hobby into eastern England has been associated with an…Read more on The energy content of dragonflies (Odonata) in relation to predation by falcons
1 January, 1996 by Peter Convey
Antarctic terrestrial communities are characterised by their geographical isolation and the survival of extreme environmental stresses. Of particular significance to life history strategies of organisms in continental and maritime. Antarctic…1 January, 1996 by Peter Convey, William Block
In contrast to northern polar areas, the dipteran fauna of Antarctica is depauperate, with only two naturally occurring species of Chironomidae. Surprisingly little is known of the biology of these…Read more on Antarctic diptera: ecology, physiology and distribution
1 January, 1996
The problem of correcting satellite altimeter measurements for errors introduced by topographic surfaces was chosen to test the capabilities of a prototype integrated geographical information system. A system to calculate…1 January, 1996 by Alistair Crame
Although it will probably never be as complete as that known from any of the other continents, the Antarctic fossil record comprises a surprising amount of information. Originally gathered primarily…Read more on Antarctica and the evolution of taxonomic diversity gradients in the marine realm
1 January, 1996
We examine the extent of overlap between South Georgia wandering albatrosses (Diomedea exulans) and local longline fishing for Patagonian toothfish (Dissostichus eleginoides), using satellite-tracking data and precise haul locations, respectively.…1 January, 1996 by Ed King
It has long since been recognised that the Ellsworth-Whitmore mountains (EWM) crustal block possesses an anomalous structural and stratigraphic history relative to its neighbouring West Antarctic crustal blocks, and the…1 January, 1996
The light climate within wet and dry samples of ten mosses from the maritime Antarctic was determined using a computer-controlled optical microprobe system. Irradiances decreased with increasing depth within the…1 January, 1996
Carbon fixation under controlled conditions was measured in three mosses from the maritime Antarctic using an infra-red gas analysis system. Gas exchange parameters were determined during each season in 1993…1 January, 1996 by Jonathan Shanklin
In this paper we briefly describe the processes which lead to the formation of the Antarctic ozone hole, the attributes of the 1994 hole in comparison with previous years and…1 January, 1996
The concept of precautionary measures for krill is discussed. A precautionary catch limit, based on the potential yield model developed by the CCAMLR Scientific Committee's Working Group on Krill (WG-Krill)…Read more on Some thoughts on precautionary measures for the krill fishery
1 January, 1996 by Eugene Murphy
Interannual variability in the Southern Ocean ecosystem has long been noted and physical factors appear to dominate the dynamics. There are, however, few ecological time series available to assess this…Read more on Environment-krill relations in the South Georgia marine ecosystem
1 January, 1996
The nomenclature of the taxon first recorded as Fragilaria (virescens) v. exigua by Grunow in Cleve & Moeller (1878) is examined with regard to the current botanical name, F. exiguiformis…1 January, 1996
The fluorite mineralization from the La Nueva Mine, has a Sm-Nd age of 130 ± 19 Ma, and thus must be related to the Lower Cretaceous late-Gondwanic extensional and magmatic…