Found 14046 items
1 June, 2000 by Nigel Meredith, Richard Horne
The temporal evolution of electron distributions and associated wave activity following substorm injections in the inner magnetosphere are investigated using data from the CRRES satellite. Equatorial electron distributions and concomitant…1 January, 2000 by Howard Roscoe
Conventional frost-point hygrometers observe frost on their cold point by optical means [1,2,3], thereby requiring several micrometres of ice to form. We have developed a new hygrometer which uses surface…1 January, 2000 by John Turner
The First International Symposium on Operational Weather Forecasting in Antarctica was held in Hobart, Australia, from 31 August to 3 September 1998. There were 40 attendees at the meeting from…1 January, 2000 by Andrew Clarke
Early embryos, blastulae, prisms and 4-arm plutei of the Antarctic shallow-water echinoid Sterechinus neumayeri were subjected to a temperature/pressure regime from -1.2 to +2.5°C and from 1 to 250 atm.…1 January, 2000 by Eric Wolff, Robert Mulvaney
The comparison between electric (electric-conductivity measurement (ECM) and dielectric profiling (DEP)) and chemical (sulphate and chloride) depth profiles along the first 400 m of the EPICA-Dome C ice core revealed…Read more on Holocene electrical and chemical measurements from the EPICA–Dome C ice core
1 January, 2000
Under the typical high-latitude conditions of temperature, productivity and settlement of chlorophyll and phaeophytin to the sediment, many benthic organisms in the Antarctic show strong seasonal variation. Although meiofauna comprise…1 January, 2000
A major ductile fault zone, the eastern Palmer Land shear zone, has been identified east of the spine of the southern Antarctic Peninsula. This shear zone separates newly identified geological…1 January, 2000 by Vsevolod Afanasyev
We review the general search problem of how to find randomly located objects that can only be detected in the limited vicinity of a forager, and discuss its quantitative description…1 January, 2000 by Michael Pinnock
We have found observational evidence for a rapid communication of interplanetary magnetic field (IMF) changes to the global ionosphere and evidence for the state of the magnetosphere in the previous…1 January, 2000
The provisioning strategies of two closely related species of albatross breeding sympatrically were studied at Campbell Island, New Zealand. Black-browed Albatrosses (Diomedea melanophrys) had a higher provisioning rate of chicks…1 January, 2000
We examined the provisioning strategy of a long-lived seabird to test the prediction from life-history theory that adults should preferentially allocate resources towards their own needs rather than towards their…1 January, 2000
The effects of growth temperature on soluble carbohydrate and lipid content of Humicola marvinii, Geomyces pannorum and Mortierella elongata isolated from the Antarctic (Signy Island; 60° 43′S, 45°38′W) were investigated.…1 January, 2000 by Roger Worland
Panagrolaimus davidi is a freeze-tolerant Antarctic nematode which survives extensive intracellular freezing. This paper describes the development of culture techniques which provide clean samples, with a high degree of freeze…1 January, 2000
The eight dominant culturable members of an Antarctic fellfield soil bacterial community were four Arthrobacter species, Sanguibacter suarezii, Aureobacterium testaceum, a Bacillus sp., and a Pseudomonas sp.. All of the…1 January, 2000
Chlorophyll a and nutrient concentrations along with temperature and salinity values were measured at 22 CTD stations along a 735-km transect running to the northwest of the island of South…1 January, 2000 by David Pearce
Water samples from a range of fresh-water Antarctic lakes on Signy Island (South Orkney Islands: 60°45′S, 45 °38′W) were examined for the presence of virus-like particles (VLPs) during the 1998/1999 field…1 January, 2000 by Eric Wolff
Ice cores are an excellent way of finding out how the atmosphere has changed because climate signals and many forcing factors for climate are present in the same core. Their…1 January, 2000 by Andrew Wood
We develop a new approach to quantifying habitat use within the foraging ranges of satellite-tracked seabirds. We applied kernel estimation techniques to 167 days (3738 locations) of data from Black-browed…1 January, 2000
Gravel-free, high-resolution (1-metre spacing, 32 channel) particle size data from the CRP-2/2A drill core indicate that many of the diamictites were likely deposited from floating ice. Textural dislocations occur at…1 January, 2000 by Roger Worland, William Block
Heleomyza borealis Boh. (Diptera, Heleomyzidae) overwinters as larvae in Arctic habitats, where they may experience winter temperatures below − 15°C. The larvae freeze at c.− 7°C but in acclimation experiments 80% survived…Read more on Survival of Heleomyza borealis (Diptera, Heleomyzidae) larvae down to -60oC
1 January, 2000 by Roger Worland, Peter Convey
This study examined the rate of cold hardening of a field population of Antarctic springtails and the effect of eating food with particular levels of ice nucleating activity on the…1 January, 2000 by Roger Worland
The effect of consuming terrestrial algae on the cold tolerance of two Antarctic micro-arthropods was examined. From the results of preferential feeding experiments, seven species of Antarctic terrestrial micro-algae were…1 January, 2000 by Richard Horne
SPEAR is a new polar cap HF radar facility which is to be deployed on Svalbard. The principal capabilities of SPEAR will include the generation of artificial plasma irregularities, operation…1 January, 2000
Commercial sealing in the 18th and 19th centuries had a major impact on the Antarctic and subantarctic fur seal populations (Arctocephalus gazella and A. tropicalis) in the Southern Ocean. The…1 January, 2000
Cyanobacteria are primitive phototrophic prokaryotes whose long evolutionary history dates back to the Proterozoic era. Their ubiquity on the planet and dominance in hot and cold deserts is a measure…1 January, 2000
Surface habitats in Antarctic deserts are near the limits of life on Earth and resemble those hypothesized for early Mars. Cyanobacteria dominate the transient riverbeds, stromatolitic sediments in ice-covered lakes,…Read more on Antarctic ecosystems as models for extraterrestrial surface habitats
1 January, 2000
Fourier-transform laser Raman spectroscopy in the near infrared (1064 nm) has been used to characterize a variety of key pigments and biomolecules produced by cyanobacteria and other stress-tolerant microbes in…1 January, 2000
Lichens are found at the limits of polar life in the Antarctic Dry Valleys under extreme conditions of UVB radiation, desiccation and low temperature. They may even have evolved in…Read more on Lichens at the limits of life: past perspectives and modern technology
1 January, 2000 by Martin Collins
The commensal relationship between a snailfish, tentatively identified as Careproctus sp. (Osteichthyes: Liparidae), and the lithodid crab Paralomis formosa (Crustacea: Lithodidae) was photographed in situ using a baited camera vehicle,…1 January, 2000
The validity of a radiative transfer model can be checked either by comparing its results with measurements or with solutions for artificial cases. Unfortunately, neither type of comparison can guarantee…Read more on From model intercomparison toward benchmark UV spectra for six real atmospheric cases
1 January, 2000
Samples were collected from the top 200 m of the water column at 50 stations during two cruises in different, near equinoctial seasons on an Atlantic transect near the 20°W…Read more on Bacterial growth and grazing loss in contrasting areas of North and South Atlantic
1 January, 2000
Krill, or euphausiids, a group of immense importance in marine ecosystems, comprises over 80 species, most of which are planktonic. Krill are widespread with species to be found in all…1 January, 2000
A series of experiments was carried out in February 1999 at South Georgia (Subarea 48.3) to examine the effects of different weighting regimes on the incidental mortality of birds caught…1 January, 2000 by Michael Pinnock
The Super Dual Auroral Radar Network (SuperDARN) radars are proving to be a very powerful experimental tool for exploring solar wind-magnetosphere-ionosphere interactions. They measure the autocorrelation function (ACF) of the…1 January, 2000 by Lloyd Peck
Antarctic anemones of the genus Halcampoides inhabit low intertidal and shallow subtidal zones. They readily burrow into soft sediments following disturbance. The process of re-burying was recorded using time-lapse video…Read more on Burrowing in the Antarctic anemone, Halcampoides sp., from Signy Island, Antarctica
1 January, 2000
Large, biomass-dominant Southern Ocean copepod species have been much studied, but small and mesopelagic species also play major rôles in these ecosystems. However, little is known of some basic aspects…1 January, 2000
Excretion by Antarctic krill Euphausia superba (hereafter ‘‘krill’’) is measured typically in small containers of filtered seawater for 12–24 h, which may cause a reduction of swimming, feeding, and metabolism.…Read more on Ammonium excretion by Antarctic krill Euphausia superba at South Georgia
1 January, 2000
The Mana Pools sedimentary basin lies within the Zambezi mobile belt in northern Zimbabwe. New and preexisting magnetotelluric data and the available seismic reflection data are used to constrain the…Read more on A magnetotelluric model of the Mana Pools basin, northern Zimbabwe
1 January, 2000 by Roger Worland, William Block
Hydromedion sparsutum is a locally abundant herbivorous beetle on the sub-Antarctic island of South Georgia, often living in close association with the tussock grass Parodiochloa flabellata. Over a 4-day period…1 January, 2000 by David Vaughan
It has been suggested that as much as 90% of the discharge from the Antarctic Ice Sheet is drained through a small number of fast-moving ice streams and outlet glaciers…Read more on Widespread complex flow in the interior of the Antarctic Ice Sheet
1 January, 2000
Phosphorus is scarce in Beacon Sandstone of the McMurdo Dry Valleys, Antarctica, and any input from precipitation is minimal. In endolithic microbial communities recycling of P by the action of…Read more on Phosphatase activities of endolithic communities in rocks of the Antarctic Dry Valleys
1 January, 2000
The phosphomonoesterase activity of a microbialcommunity dominated by Chroococcidiopsis in arock sample from the Antarctic dry desert was comparedwith that of a non-axenic culture of thecyanobacterium isolated from the same…1 January, 2000
We report low temperature gradients (from 60% to 12% of geothermal), and extrapolated temperatures offset from modern bottom water temperatures, in sediments from the central Scotia Sea. We examine possible…1 January, 2000
Tape recordings of two types of vocalisations were used to assess burrow occupancy by white-chinned petrels (Procellaria aequinoctialis) at South Georgia. Birds responded to the rattle call on 74% of…1 January, 2000
The white-chinned petrel (Procellaria aequinoctialis) is an abundant, widespread petrel breeding in tussock grassland at sub-Antarctic islands. Over the last decade it has been killed in large numbers in temperate…1 January, 2000
The foraging range and principal feeding areas of White-chinned Petrels breeding at South Georgia were determined using satellite telemetry. Foraging trips during incubation lasted 12–15 days and covered 3000–8000 km…1 January, 2000 by William Block
Specimens of six enchytraeid species from a wide range of terrestrial habitats were cooled to –25oC and rewarmed at 1oC min-1 and their cryobiological features measured by DSC. All were…Read more on DSC studies of freezing in terrestrial enchytraeids (Annelida: Oligochaeta)
1 January, 2000
The absolute gut evacuation rate (GER) (g day−1) of Harpagifer antarcticus increased with increasing ration mass, fish mass only influenced the absolute GER at a daily ration level of 0·3%…1 January, 2000
This study tests the hypothesis that an endothermic homeotherm should minimise heat flux in cold polar waters by minimising skin temperature. Temperature variability was measured at the surface of the…Read more on Skin temperatures during free-ranging swimming and diving in Antarctic fur seals
1 January, 2000
1. The study tested the hypothesis that the occurrence of pregnancy in mammals that are capital breeders will be most closely related to state variables that are indices of food…Read more on State-dependent fertility in pinnipeds: contrasting capital and income breeders
1 January, 2000 by Eugene Murphy, Philip Trathan
Ocean physics is a key aspect of the operation of island ecosystems, yet the hydrodynamics is sometimes poorly understood. A high-resolution oceanographic survey to the north of South Georgia identified…1 January, 2000 by Jonathan Watkins
Much of the distribution range of Antarctic krill, Euphausia superba, is covered by permanent or seasonal sea ice. Sea ice extent has been implicated as a major factor affecting reproductive…Read more on Effects of sea ice cover on the swarming behaviour of Antarctic krill,Euphausia superba
1 January, 2000
On Bird Island, South Georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for Campylobacter jejuni. C. jejuni subsp. jejuni was recovered…1 January, 2000
1 The population density, diversity and productivity of the microbial plankton in an oligotrophic maritime Antarctic lake were studied for a 15-month period between December 1994 and February 1996. 2…Read more on Temporal plankton dynamics in an oligotrophic maritime Antarctic lake
1 January, 2000
Cetricycas antarcticus gen. et sp. nov. occurs in the Late Coniacian to Campanian Lachman Crags Member of the Santa Marta Formation, Marambio Group, James Ross Island, Antarctica. The petrified trunk…Read more on A petrified cycad trunk from the Late Cretaceous of the Larsen Basin, Antarctica
1 January, 2000
A macroflora from John Peaks, Powell Island, contains Sagenopteris nilssoniana, Cladophlebis oblonga, Brachyphyllum sp., Elatocladus confertus, and Sphenopteris sp. The macroflora is best correlated with the Botany Bay Group flora,…1 January, 2000
Publication of the Composite gazetteer of Antarctica by the SCAR Working Group on Geodesy and Geographic Information is a major milestone in the evolution of Antarctic toponymy. It has taken…1 January, 2000 by Gareth Chisham, Michael Pinnock
Poleward‐moving line‐of‐sight velocity “flow bursts” have been observed in the cusp by two southern hemisphere SuperDARN HF radars with overlapping fields‐of‐view. This has allowed the estimation of unambiguous two‐dimensional velocity…1 January, 2000 by Gareth Chisham, Michael Pinnock
We present data from conjugate SuperDARN radars describing the high-latitude ionosphere's response to changes in the direction of IMF By during a period of steady IMF Bz southward and Bx…1 January, 2000 by Andrew Clarke
1. We have examined large-scale geographical patterns in species richness for continental shelf bryozoan assemblages in the North Atlantic. Bryozoans are common and often abundant benthic organisms, but they have…1 January, 2000
As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of ∼106 km2 and total as much as…Read more on The state and future of Mars polar science and exploration
1 January, 2000 by Mark Clilverd
Unusually low whistler mode group delay times are observed by VLF Doppler receivers at both Faraday, Antarctica, and Dunedin, New Zealand, following magnetic storms. These are typically caused by plasmaspheric…1 January, 2000 by Michael Pinnock
The antiparallel merging hypothesis states that reconnection takes place on the dayside magnetopause where the solar and geomagnetic fields are oppositely directed. With this criterion, we have mapped the predicted…Read more on The ionospheric footprint of antiparallel merging regions on the dayside magnetopause
1 January, 2000
We aim to identify the important steps in the evolution of the ecosystem approach to management under the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR). The first…1 January, 2000 by Peter Convey
The South Sandwich Islands are an isolated maritime Antarctic volcanic island arc 550-600km south-east of South Georgia. The terrestrial biology of the islands, with emphasis on the unique habitats associated…Read more on The terrestrial micro-arthropod fauna of the South Sandwich Islands
1 January, 2000 by Dominic Hodgson, Helen Peat, Peter Convey
Aim To carry out as comprehensive a survey as practicable of the flora (higher plants, mosses, liverworts, lichens, basidiomycete fungi and diatoms) of the isolated, volcanically active, South Sandwich Islands…1 January, 2000 by Helen Peat, Peter Convey
This paper documents the previously undescribed terrestrial fauna (mites, nematodes, tardigrades) and flora (liverworts, mosses and lichens) of Marion Nunataks, Charcot Island (69°45'S 075°15'W). Species diversity in all groups is…1 January, 2000 by Roger Worland, Peter Convey
In studies of three common, freezing susceptible, Antarctic microarthropods, the springtail Cryptopygus antarcticus and the mites Alaskozetes antarcticus and Halozetes belgicae, we report (i) the consequences on cold tolerance of…Read more on Refining the risk of freezing mortality for Antarctic terrestrial microarthropods
1 January, 2000 by Roger Worland, Peter Convey
Free-living microbivorous nematodes become numerically dominant in Antarctic terrestrial faunas as environmental conditions become more severe, while also reaching very high levels of abundance in moist, vegetated habitats. Nematodes have…Read more on Survival of freezing by free-living Antarctic soil nematodes
1 January, 2000 by Alistair Crame
A major new inventory of living marine Bivalvia (Mollusca) is based on 29 regional faunas. These again pick out strong latitudinal and longitudinal gradients in taxonomic diversity, but there are…1 January, 2000 by Alistair Crame
At the present day the Class Bivalvia comprises some 8000 species, sub-divided into approximately 700 genera, 107 families, and 41 superfamilies (Morton, 1996, and references therein). It represents one of…Read more on Intrinsic and extrinsic controls on the diversification of the Bivalvia
1 January, 2000 by Alistair Crame
Bivalves have been fundamental in developing the understanding of large-scale biodiversity patterns in the marine realm. A new study based on 29 regional bivalve faunas indicates that both latitudinal and…Read more on The nature and origin of taxonomic diversity gradients in marine bivalves
1 January, 2000
In a previous study at South Georgia, carnivory was invoked as a cause of high polyunsaturated fatty acid (PUFA) content of Antarctic krill, Euphausia superba. To examine this, krill were…