Found 14040 items
1 January, 1998
This study examined the foraging locations of adult male and female Antarctic fur seals (Arctocephalus gazella) in the Scotia Sea during the postbreeding period. Satellite transmitters were used to track…Read more on Dispersal of male and female Antarctic fur seals (Arctocephalus gazella)
1 January, 1998 by Jonathan Watkins
Accurate estimation of krill biomass by acoustic techniques is dependent on a number of factors of which one of the most fundamental is accurate echosounder calibration. The Simrad EK500 scientific…1 January, 1998 by Jonathan Watkins, Peter Ward
Acoustic surveys in the vicinity of the sub-Antarctic island of South Georgia during a period of exceptionally calm weather revealed the existence of a number of horizontally extensive yet vertically…Read more on Acoustic discrimination of Southern Ocean zooplankton
1 January, 1998 by Jonathan Watkins
Acoustic Dopplerd current profilers (ADCPs) are being used increasingly to derive estimates of zooplankton and micronekton abundance. The absence of a practical means for users to perform ADCP calibration, however,…1 January, 1998 by Paul Rodhouse
Cephalopod fisheries are among the few still with some local potential for expansion; in fact, as groundfish landings have declined globally, cephalopod landings have increased. We propose the hypothesis that,…Read more on Cephalopod and groundfish landings: evidence for ecological change in global fisheries?
1 January, 1998
Fertile fern foliage described as Lophosoria cupulatus sp. nov. contains the distinctive spore Cyatheacidites annulatus. The fossil foliage is morphologically similar to the Early Cretaceous form-genera Gleichenites and Microphyllopteris, whose…Read more on Early Cretaceous fern foliage from President Head, Snow Island, Antarctica
1 January, 1998
The power law dependence of the power spectrum of auroral indices, and in-situ magnetic field observations in the earth's geotail, may be evidence that the coupled solar wind-magnetospheric system exhibits…Read more on A simple avalanche model as an analogue for magnetospheric activity
1 January, 1998 by Mark Clilverd
The aa index provides the longest continuous data set which can be used in the analysis of magnetospheric and ionospheric phenomenology. All phases of the solar cycle show increases in…Read more on Increased magnetic storm activity from 1868 to 1995
1 January, 1998
The mean number of primaries molted by Gray-headed Albatrosses (Diomedea chrysostoma) varied with year and previous breeding experience independently, but was not related to individual reproductive success over a longer…Read more on factors affecting primary molt in the gray-headed albatross
1 January, 1998
We compare observed temperature variations in Antarctica with climate-model runs over the last century. The models used are three coupled global climate models (GCMs) — the UKMO, the CSIRO and…1 January, 1998 by Peter Convey
The oribatid mite Alaskozetes antarcticus is found over a wide range of southern latitudes, between the cool temperate Falkland Islands (51–52°S) and Alexander Island (71–72°S). It is one of the…1 January, 1998
Deception Island is a large volcanic centre in Bransfield Strait, a very young marginal basin between the South Shetland Islands and Antarctic Peninsula. It has a historical record of volcanic…1 January, 1998
The effect of varying diet and environmental conditions at the Marginal Ice Zone (MIZ) on the fatty acid and hydrocarbon compositions of five species of copepod and krill, Euphausia superba,…1 January, 1998 by Andrew Clarke
Particulate material recovered over an 18-month period from sediment traps deployed at a shallow-water nearshore Antarctic site was analysed for photosynthetic pigments, aliphatic hydrocarbons and fatty acids. All components showed…1 January, 1998
The North Scotia Ridge is a series of islands and submarine ridges extending 2000 km from Tierra del Fuego to South Georgia in the western South Atlantic. The ridge forms…1 January, 1998
The Heritage Range of the southern Ellsworth Mountains, West Antarctica, is composed of Cambrian to Permian sedimentary and volcanic rocks, which were deformed during the Permo-Triassic Gondwanian orogeny. The structural…1 January, 1998
The Falkland Islands lie on a displaced crustal block presently forming part of the South American plate. The islands possess two roughly orthogonal structural grains, the relative chronology of which…1 January, 1998
Colonization of artificial substrata was monitored on sheltered rocky shores at Husvik, South Georgia (54° 11′S; 36° 40′W) and Cumbrae, Scotland (55° 46′N; 4° 55′W) from mid summer to early…1 January, 1998
Stauromedusae are cnidarians that have attracted relatively little ecological study, especially in the southern hemisphere. They are Scyphozoa that develop directly from the scyphistoma, and each consists of a calyx…1 January, 1998
The Holocene Murta basalts represent a small volume monogenetic centre located in the northern Patagonian Andes at the latitude of the Chile Triple Junction. These basalts show morphological evidence of…1 January, 1998
Strontium isotope stratigraphy provides a chronology for Cenozoic cryogenic strata in the northern Antarctic Peninsula and allows an assessment of diachronism in onset of glacial conditions between East and West…1 January, 1998
Aptian to Pliocene time-series of X-ray fluorescence data from the Antarctic Peninsula are used to assess the degree of chemical weathering and maturity of sediments deposited prior, and subsequent to…1 January, 1998
Clay mineral, sedimentological and geochemical data show that the northern Antarctic Peninsula (Seymour Island, La Meseta Formation) experienced a climatic deterioration from very warm, non-seasonally wet conditions at the end…1 January, 1998
The breakup of ice shelves has been widely regarded as an indicator of climate change1, with observations around the Antarctic Peninsula having shown a pattern of gradual retreat, associated with…Read more on Breakup and conditions for stability of the northern Larsen Ice Shelf, Antarctica
1 January, 1998
The Mesozoic Fossil Bluff Group of Alexander Island contains trench-slope and forearc basin deposits that formed during the eastward subduction of oceanic crust beneath the Antarctic Peninsula region. The oldest…1 January, 1998 by Mervyn Freeman
A sharp latitudinal gradient in the Doppler spectral width is often observed in the nightside data from the SuperDARN HF radars. We use an excellent conjunction between the Halley HF…Read more on The nightside ionospheric response to IMF by changes
1 January, 1998
The specification, development and deployment of an automated observatory designed to operate unattended for a year in the extreme climatic conditions of the polar regions is presented. Solar- and wind-powered…Read more on Automated observatories for geospace research in polar regions
1 January, 1998 by Andrew Clarke
Antarctic biologists frequently emphasize the differences between the modern Antarctic environment and its fauna, and aquatic habitats and faunas elsewhere in the world. While it is valid to portray Antarctica…Read more on A comparison of adaptive radiations of Antarctic fish with those of nonAntarctic fish
1 January, 1998
Lichens have a primary role in the biodeterioration of rock substrata and in soil formation. In extreme Antarctic rock-face habitats, their exposed epilithic growth form makes them vulnerable to environmental…1 January, 1998
Information on natural mortality rates of the mackerel icefish (Champsocephalus gunnari) from the period prior to known large-scale commercial harvesting is discussed. After careful consideration of the data and available…1 January, 1998 by Mervyn Freeman
We compare the large-scale goemagnetic response to the three magnetic clouds observed by Wind in October 1995 (OCT95), May 1996 (MAY96), and January 1997 (JAN97), studying specifically storm and substorm…Read more on Geoeffectiveness of three Wind magnetic clouds: A comparative study
1 January, 1998
The Dufek intrusion, in the northern part of the Pensacola Mountains, Antarctica, is part of an extensive, Middle Jurassic igneous province that was related to, and emplaced just prior to…1 January, 1998
Vertical facies associations within the CRP- 1 drillcorc reveal a strong cyclicity and facilitate the development of a sequence stratigraphic framework. The sedimentary record appears to be punctuated by a…1 January, 1998 by Adrian Fox
Aerial photography has been used as a mapping tool in the Antarctic Peninsula region since the late 1920s. Following pioneering work by Wilkins in 1928, Ellsworth in 1934 and the…Read more on Climate-change indicators from Archival aerial photography of the Antarctic Peninsula
1 January, 1998 by Mervyn Freeman
The buffetting of the magnetosphere by the solar wind is the cause of many phenomena in the magnetosphere and the ionosphere, and affects the way in which we observe many…Read more on Magnetopause motions in a Newton-Busemann approach
1 January, 1998
We describe the calibration and interpretation of interferograms generated from ERS-I synthetic aperture radar Single Look Complex (SAR. SLC) images of the Rutford Ice Stream area. Ground surveys provide over…1 January, 1998
The ability of the Utah energy-balance and snowmelt model (UEB) to simulate decline in snow water equivalent (SWE) at an extreme location was assessed. Field data were collected at Paternoster…Read more on Snowmelt modelling on Signy Island, South Orkney Islands
1 January, 1998
Cores and 3.5 kHz, sub-bottom profiles collected from the continental slope and rise near 64°S, 52°W, off the tip of the Antarctic Peninsula, reveal transport and depositional processes in a…Read more on A sediment record of cyclic bottom-current variability from the northwest Weddell Sea
1 January, 1998 by Paul Rodhouse
A scientific research fishing expedition targeting the oceanic/slope ommastrephid squid Martialia hyadesi was undertaken by a Korean-registered squid jigger in CCAMLR area 48.3, near South Georgia, in June 1996, providing…1 January, 1998 by Jonathan Watkins, Paul Rodhouse
During a research cruise of the British Antarctic Survey ship RRS James Clark Ross in February 1996, more than 2 000 individuals of the ommastrephid squid, Martialia hyadesi, were caught…Read more on Attribtuion of acoustic echoes to squid in the south Atlantic
1 January, 1998
The Mesozoic-Cenozoic volcanic arc of the Antarctic Peninsula is represented on Adelaide Island by a sedimentary and volcanic succession intruded by plutons. 40Ar-39 Ar step-heating age spectra have been obtained…Read more on The stratigraphy and geochronology of Adelaide Island
1 January, 1998 by Paul Rodhouse
The Argentinean short-finned squid, Illex argentinus, is distributed along the shelf and slope in the western South Atlantic from 22° to 54°S. Since 1977 catches by a local and an…1 January, 1998 by Eric Wolff
Two years worth of daily aerosol data has been collected from Halley station, Antarctica, between February 1991 and February 1993. The seasonal cycle of sea-salt aerosol was found to peak…1 January, 1998
Rock temperature data collected at one-minute intervals from both the horizontal surface and the four cardinal directions of a rock outcrop show the influence of record interval and aspect on…1 January, 1998
US Joint Ice Center (JIC) Antarctic sea ice extent data, the longest continuous series of its kind for this part of the world, are compared with direct passive microwave-based estimates…1 January, 1998
The Byers Group, exposed in the western South Shetland Islands, is a thick (at least 2.7 km) succession recording Late Jurassic–Early Cretaceous sedimentation and volcanism on the Pacific flank of…1 January, 1998
The northern, James Ross Island region of the Larsen Basin, on the eastern, back-arc margin of the Antarctic Peninsula magmatic arc, includes one of the thickest and most complete Upper…1 January, 1998 by Richard Hindmarsh, Richard Hindmarsh
The time-dependent physics of ice sublimation through thin layers of till is considered, to determine whether sublimation could be sufficiently slow to permit the preservation of ice for 8 Ma…Read more on Sublimation of ice through sediment in Beacon Valley, Antarctica
1 January, 1998 by Dominic Hodgson, Nadine Johnston
A recent rapid increase in the number of Antarctic fur seals on Signy Island has caused extensive changes to terrestrial and freshwater ecosystems. A palaeolimnological study was carried out to…1 January, 1998 by Dominic Hodgson
Lake sediment cores from Midge Lake, Livingston Island, South Shetland Islands and Sombre Lake, Signy Island, South Orkney Islands were analysed for volcanic tephra using light microscopy and magnetic susceptibility.…1 January, 1998 by William Block
Extensive studies on invertebrates from Ny-Ålesund, Spitsbergen, Svalbard and more limited data on aphids from Abisko, Sweden, produced the following main conclusions: (1) The population response to raised summer temperatures…1 January, 1998 by Eugene Murphy
Historical observations of the large-scale flow and frontal structure of the Antarctic Circumpolar Current in the Scotia Sea region were combined with the wind-induced surface Ekman transport to produce a…1 January, 1998 by Richard Horne
The possibility of electron stochastic energization to relativisitic energies (≥ 1 MeV) via resonant wave-particle interactions during a magnetic storm is explored. The minimum electron energy Emin for cyclotron resonant…1 January, 1998 by John King
Atmospheric wave-trains of climate anomalies are investigated as a candidate for linking low and high latitude atmospheric signals during Pacific Ocean warm (ENSO) and cold (La Niña) events. Study results,…1 January, 1998
An area of mudwave development has been identified from the northwestern Powell Basin, northern Weddell Sea, Antarctica. The wave-field is located near the base of the continental slope in water…1 January, 1998
F region peak heights, derived from ionospheric scaled parameters through 38-year data series from both Argentine Islands (65°S, 64°W) and Port Stanley (52°S, 58°W) have been analyzed for signatures of…1 January, 1998
The implementation of a technique to derive mesospheric winds from HF radar observations of meteor echoes at Halley (76°S, 27°W), Antarctica, is described. The meteor echoes are observed at near…1 January, 1998 by Anna Jones, John Turner
A regular occurrence during the 1990s has been the excursion of the edge of the springtime Antarctic ozone hole over the southernmost region of the South American continent. Given the…1 January, 1998
Observations of satellite passes monitored at Halley and Terra Nova Bay have been combined to produce for the first time measurements of ionospheric electron content spanning the Antarctic continent. Results…Read more on Ionospheric electron content across the Antarctic continent
1 January, 1998
The dynasonde at Halley, Antarctica, is operated throughout the year making ionogram soundings every five minutes. The extensive database of observations from 1993 and 1994 has been processed to investigate…1 January, 1998
Since 1959 the British Antarctic Survey (BAS) has undertaken reconnaissance gravity surveys of the Antarctic Peninsula. Approximately 1500 on-rock and about 600 on-snow station values were measured. Continuing climatic, topographical…Read more on Towards a new free air anomaly map of the Antarctic Peninsula
1 January, 1998
New constraints on the age of the Cockburn Island Formation, northern Antarctic Peninsula, resulting from whole rock laser-stepped heated 40Ar–39Ar dating of associated basalt and palaeomagnetic re-calibration of the ranges…1 January, 1998
The longest-known pectinid-bearing deposit in the Antarctic, the "Pecten-conglomerate" of Cockburn Island in the James Ross Island group, northern Antarctic Peninsula, is herein formally named the Cockburn Island Formation. A…1 January, 1998
Antarctic late Cenozoic pectinid-bearing sedimentary strata are chiefly confined to localities in the northern part of the Antarctic Peninsula, in the McMurdo Sound area, and Marine Plain, East Antarctica. Ages…Read more on Stratigraphy of Antarctic late Cenozoic pectinid-bearing deposits
1 January, 1998
Macrofossil content from the Miocene part of CRP-1 core, Cape Roberts (Victoria Land Basin) is scant and mostly limited to a few pectinid bivalves and serpulid polychaetes. Selective diagenesis has…1 January, 1998
Levels of persistent organic pollutants (POPs), such as polychlorinated biphenyls and pesticides have been determined in ambient air at Signy Island, Antarctica, over a period of 17 weeks. Mean concentrations…1 January, 1998 by John King, Thomas Lachlan-Cope
We use snow surface temperatures obtained from thermal infrared (TIR) satellite imagery, together with radiosonde profiles of free-air temperature and high-resolution topographic data to study the thermal structure of the…1 January, 1998 by John King
Temperature records from stations on the west coast of the Antarctic Peninsula show a very high level of interannual variability and, over the last 50 years, larger warming trends than…1 January, 1998 by Andrew Clarke
The temperature of the Southern Ocean has undergone an overall reduction from about 20 °C to −1.8 °C over the last 55–60 million years. To date, the Southern Ocean is…Read more on Age, growth and maximum size of Antarctic notothenioid fish — revisited
1 January, 1998 by John King
Long term air and snowfall chemistry measurements have been performed at the three coastal Antarctic stations Dumont d'Urville (66°40′S, 140°1′E), Neumayer (70°39′S, 8°15′W), and Halley (75°35′S, 26°19′W). The results have…