Showing 11862 items
1 January, 1999 by Philip Leat
The Middle Jurassic–Lower Cretaceous Fossil Bluff Group of Alexander Island, Antarctica represents the fill of a fore-arc basin unconformably overlying an accretionary complex. Like most fore-arc basins, this example had…1 January, 1999 by Keith Makinson, Keith Nicholls
A depth-averaged tidal model has been applied to the southern Weddell Sea. The model domain covers the southern continental shelf, including the ocean cavity beneath Filchner-Ronne Ice Shelf. Reasonable agreement…1 January, 1999
Sixty species of Acari are recorded from the sub-Antarctic Marion and Prince Edward Islands (the Prince Edward archipelago). Twenty of the 45 species collected on recent expeditions are new and…Read more on New records of Acari from the sub-Antarctic Prince Edward Islands
1 January, 1999 by Gareth Marshall, John Turner
Using data obtained during January 1995—the third of three special observing periods associated with the Antarctic First Regional Observing Study of the Troposphere project—over a sector of the Southern Ocean…1 January, 1999
Anterior eye structure and retinal visual fields were determined in King Penguins Aptenodytes patagonicus using keratometry and an ophthalmoscopic reflex technique. The cornea is relatively flat (radius 32.9 mm) and…Read more on Eye structure and foraging in King Penguins Aptenodytes patagonicus
1 January, 1999
The breeding performance of higher predators has often been used to monitor fluctuations in the abundance of important prey stocks in marine ecosystems. The development of electronic data-loggers in recent…Read more on Can marine mammals be used to monitor oceanographic conditions?
1 January, 1999 by Mark Clilverd
It is well known that the resonant frequency of geomagnetic field lines is determined by the magnetic field and plasma density. We used cross-phase and related methods to determine the…1 January, 1999
Pre-tectonic metagabbroic rocks emplaced into the Glenfinnan and Loch Eil groups of the Moine Supergroup give a U–-Pb zircon age of 873 ± 6 Ma. This new age for the…1 January, 1999
The effect of increased ion production due to the precipitation of both ions and electrons in the cusp region has been studied using a computational model of the high-latitude ionosphere.…Read more on Modeling the ionospheric effects of ion and electron precipitation in the cusp
1 January, 1999
The aim of this study is to examine the information given by various indices of rhizome morphology that describe grazed and ungrazed rhizome systems of Acaena magellanica (Rosaceae). Internode lengths,…1 January, 1999
The effects of UV-B exclusion and enhancement of solar radiation on photosynthesis of the two phanerogams which occur in the maritime Antarctic, Deschampsia antarctica and Colobanthus quitensis, and the moss…1 January, 1999
To assess large-whale stocks following the cessation of land-based South Georgia whaling in 1965, we report three independent sighting databases: a cruise in 1997, observations from Bird Island (NW of…Read more on Relative abundance of large whales around South Georgia (1979–1998
1 January, 1999
Moraine Corrie Glacier lies close to the UK summer station Fossil Bluff where meteorological measurements have been taken intermittently since 1961. The elevation of the glacier surface has been measured…Read more on Surface ablation rates on Moraine Corrie Glacier, Antarctica
1 January, 1999 by Eugene Murphy, Paul Rodhouse
The short life span of cephalopods suggests a potential for high sensitivity to the artificial selective effects of human exploitation. To explore the effects of such selection life-history optimisation was…1 January, 1999 by Mervyn Freeman, Michael Pinnock
We examined the dynamics of the ionospheric plasma in the dayside sector by using the HF radar data at Iceland West and at Finland from 1100 to 1230 UT on…Read more on A very large scale flow burst observed by the SuperDARN radars
1 January, 1999 by John Turner, Robert Mulvaney
With the planned European Programme for Ice Coring in Antarctica in Dronning Maud Land it is important to understand the processes leading to accumulation for successful interpretation of core data.…1 January, 1999
Red sprites consist of multiple ionised columns extending above a thunderstorm from ∼30 km to ∼90 km. Electron densities in these columns are very much larger than the ambient background,…1 January, 1999
Meesia uliginosa Hedw. and the family Meesiaceae are recorded for the first time in the Antarctic. The species is occasional on Joinville and James Ross Islands near the Trinity Peninsula,…Read more on Meesia uliginosa Hedw. (Musci, Meesiaceae) in Antarctica
1 January, 1999
A detailed Rb-Sr geochronological and geochemical study has been carried out on granitoids of the North Patagonian batholith in Aysén. The results for 25 plutonic bodies reveal a complex age…Read more on Mesozoic-Cenozoic evolution of the North Patagonian Batholith in Aysen, southern Chile
1 January, 1999 by Robert Mulvaney
Two 10cm lengths of firn core from the Dyer Plateau (700° 3l'S, 65°0l'W), Antarctic Peninsula, were used to carry out a laboratory experiment to investigate the migration of methane sulphonate,…Read more on Laboratory study of the migration of methane sulphonate in firn
1 January, 1999 by Lloyd Peck
Ice disturbance is possibly the major structuring element of polar nearshore biological communities. Effects range from encapsulation by ice forming on rock substrata to gouging and trampling by bergs. Some…1 January, 1999 by Michael Pinnock
Data from HF-radars are used to make the first simultaneous conjugate measurements of the dayside reconnection electric field. A period of 4 h around local magnetic noon are studied during…1 January, 1999
Fossil angiosperm wood is abundant within Cretaceous and Tertiary sediments on the Antarctic Peninsula. The wood, which represents the trunks and branches of large forest trees that once grew on…Read more on Reconstruction of Antarctic palaeoclimates using angiosperm wood anatomy
1 January, 1999
Fossil wood of the Atherospermataceae from the upper Cretaceous of James Ross Island, Antarctica, is described for the first time and represents the earliest record of this family in the…1 January, 1999 by Lloyd Peck
Changes in oxygen consumption, ammonia excretion and in the acid-base and energy status of various tissues were investigated in the cold stenothermal Antarctic bivalve, Limopsis marionensis, and compared to similar…1 January, 1999 by Lloyd Peck
Thermal sensitivities of maximum respiration and proton leakage were compared in gill mitochondria of the Antarctic bivalve Laternula elliptica for an assessment of the contribution of mitochondrial mechanisms to limiting…1 January, 1999
The Earth System consists of the solid planet, its atmosphere, oceans, ice and biota. These are coupled via a myriad of complex physical, chemical and biological processes, which occur over…1 January, 1999 by Michael Pinnock
Observations of plasma convection in the morning sector (0000 to 0600 magnetic local time (MLT)) during a period of northward IMF (Bz = +5 to +10 nT) on September 11,…1 January, 1999
Nitrate utilization and ammonium utilization were studied by using three algal isolates, six bacterial isolates, and a range of temperatures in chemostat and batch cultures. We quantified affinities for both…1 January, 1999
Variability in the Southern Ocean is frequently reflected in changes in the abundance of Antarctic krill Euphausia superba and subsequent effects on dependent predators. However, the nature and consequences of…1 January, 1999
The frequency and mass of meals delivered to ten Antarctic Prion Pachyptila desolata chicks nesting at Bird Island, South Georgia were examined using automated weighing systems, placed in the nest…1 January, 1999 by Eugene Murphy, Jonathan Watkins
Central to understanding krill population dynamics is knowledge of their population structure. To examine this we used length-frequency distributions from 142 wk of sampling (n = 23996 krill) of 3…1 January, 1999
We present radar measurements of the 12-hour wave, a zonal wavenumber 1 westward propagating wave that exists in the southern polar mesopause region winds (Hernandez et al, 1993; Forbes et…Read more on Spatial structure of the 12-hour wave in the Antarctic as observed by radar
1 January, 1999 by Philip Leat, Teal Riley
Jurassic magmatism in western Gondwana produced the most voluminous episode of continental volcanism in the Phanerozoic era. During the Early to Middle Jurassic, some 2.5–3 million km3 of dominantly basalt,…1 January, 1999
Recent disintegration of ice shelves on the Antarctic Peninsula has highlighted the need for a better understanding of ice shelf fracture processes generally. In this paper we present a fracture…1 January, 1999
The rates of plankton community production and respiration were determined from in vitro changes in dissolved inorganic carbon and dissolved oxygen and the incorporation of (NaHCO3)-C-14 at a coastal site…1 January, 1999
Polar patch was the name given originally to a spatially limited enhancement of the 630-nm emission observed in the dark polar cap. More recently, the term has been applied to…Read more on Riometer and HF radar signatures of polar patches
1 January, 1999
In the last decade there has been a great deal of interest in the detection and understanding of phenomena occurring above active thunderstorms. The discovery of the optical phenomena now…Read more on Red sprites, upward lightning, and VLF perturbations
1 January, 1999 by Mark Clilverd
It has been reported that propagation of very low frequency (VLF) waves in the Earthionosphere waveguide might provide an indication of imminent earthquakes [Hayakawa et al., 1996; Molchanov et al.,…Read more on Modeling of subionospheric VLF signal perturbations associated with earthquakes
1 January, 1999 by Mark Clilverd
Magnetospheric line Radiation (MLR) events are relatively narrowband VLF signals that sometimes drift in frequency, and have been observed in both ground based and satellite data sets. Line radiation has…Read more on Magnetospheric line radiation observations at Halley, Antarctica
1 January, 1999
Red sprites were discovered by chance in 1989 when a low-light TV system was pointed above an active thunderstorm. Red sprites are associated with columns of ionization in the Earth-ionosphere…Read more on VLF scattering from red sprites: Application of numerical modeling
1 January, 1999
Red sprites were discovered by chance in 1989 when a low-light TV system was pointed above an active thunderstorm. Optically, they are observed as clusters of short-lived (∼50 ms) pinkish-red…1 January, 1999 by Howard Roscoe
In June 1996, 16 UV-visible sensors from 11 institutes measured spectra of the zenith sky for more than 10 days. Spectra were analysed in real-time to determine slant column amounts…1 January, 1999 by Howard Roscoe, Thomas Lachlan-Cope
Photographs of clouds taken with a camera with a large aperture ratio must have a short depth of focus to resolve small droplets. Hence the sampling volume is small, which…1 January, 1999 by Roger Worland
Abstract.The alpine tree weta Hemidiena maori Pictet et Saussure (Orthoptera: Stenopelmatidae) is a large, flightless insect found above the treeline on many of the mountain ranges of the South Island…1 January, 1999
Miocene–Recent alkaline volcanic rocks form numerous outcrops scattered widely throughout the Antarctic Peninsula and eastern Ellsworth Land. They occur mainly as short-lived (typically 1–2 million years) monogenetic volcanic fields but…1 January, 1999
Tephrochronology studies in the south polar region are reviewed and evaluated. There have been numerous investigations of tephra layers in ice cores, reflecting the continuing importance of ice cores as…Read more on The upper Cenozoic tephra record in the south polar region: a review
1 January, 1999 by Mervyn Freeman
We firmly establish a certain class of post-midnight ELF/VLF wave events as a signature of the substorm expansion phase. These substorm chorus events (SCEs) have been observed near L =…1 January, 1999
Bryum argenteum, B. pseudotriquetrum and Ceratodon purpureus are the predominant mosses in Victoria Land, continental Antarctica. All have cosmopolitan distributions and are widespread throughout Antarctica with wide ecological amplitudes resulting…1 January, 1999 by Andrew Clarke, Lloyd Peck
A survey of pelagic larvae was undertaken between November 1992 and February 1995 at Signy Island, Antarctica (60° 43′ S, 45° 36′ W). A diver–towed net and hand–held plankton pump…1 January, 1999
The Falkland Islands are one segment of the Permo-Triassic Gondwanian Fold Belt that was displaced during the fragmentation of Gondwana. Palæomagnetic, structural and palæocurrent data, reviewed in this paper, provide…Read more on Reconstruction and break-out model for the Falkland Islands within Gondwana
1 January, 1999 by Philip Leat
Ocean floor magnetic anomalies show that New Zealand was the last continental fragment to separate from Antarctica during Gondwana break-up, drifting from Marie Byrd Land, West Antarctica, about 84 Ma…1 January, 1999
In this paper Beck (1998)reviews the database of palaeomagnetically observed rotations in the Andean margin of South America, in particular with respect to the well known change in sense of…Read more on On the mechanism of crustal block rotations in the Central Andes — Comment
1 January, 1999 by Philip Trathan
Acoustic data from the Polish FIBEX survey in the West Atlantic were analysed using recent acoustic target strength estimates of krill (SC-CAMLR, 1991a). This analysis indicated that the acoustic densities…Read more on Status of the Polish FIBEX acoustic data from the West Atlantic
1 January, 1999
This paper reports the first attempts at geo-location of albatrosses using miniature data loggers attached to seabirds for extended periods of time. The paper highlights the potential of data loggers…1 January, 1999 by David Vaughan, Gareth Marshall, John Turner
Forecasts from the ECMWF re-analysis project (ERA) covering the period 1979–1993 are used to examine the spatial and temporal distribution of net snow accumulation (precipitation minus evaporation) over the Antarctic…1 January, 1999
The Auriga Nunataks shear zone places new tectonic and temporal constraints on the Mesozoic evolution of West Antarctica. The shear zone is a long-lived, arc-orthogonal, ductile transfer fault that preserves…1 January, 1999 by David Vaughan
Recent in situ measurements of surface mass balance and improved calculation techniques are used to produce an updated assessment of net surface mass balance over Antarctica. A new elevation model…Read more on Reassessment of net surface mass balance in Antarctica
1 January, 1999 by Paul Rodhouse
Mastigophora brevipinnis Owen, 1856, is a ‘fossil teuthid’ presently considered to be a member of the coleoid cephalopod Suborder Loligosepiina Jeletzky, which in turn has been placed by various authors…1 January, 1999 by Claire Waluda, Paul Rodhouse, Philip Trathan
The fishery for Illex argentinus in the Southwest Atlantic is subject to large inter-annual variability in recruitment strength. In this paper we attempt to build a predictive model using sea…1 January, 1999
Consistent diel patterns in foraging depths have been recorded in several avian predators which feed on pelagic prey, but nothing is known about such effects in bottom feeding seabirds. In…1 January, 1999
Mesozooplankton (predominantly 200–2000 μm) were sampled at a shelf and an oceanic station close to South Georgia, South Atlantic, during austral spring (October/November) 1997. Onshelf zooplankton biomass was extremely high at…1 January, 1999 by Jonathan Watkins
There is considerable spatial structure within the South Georgia krill-based ecosystem in terms of predator demand, commercial fishery pressure and krill abundance. Here we investigate the hypothesis that there is…Read more on Variation in the distribution of Antarctic krill Euphausia superba around South Georgia
1 January, 1999 by Jonathan Watkins
A composite recruitment index based on density data derived from acoustic surveys and on length-frequency data obtained from either target or station net hauls is described. This composite index is…1 January, 1999
The hypothesis of self-organised criticality (SOC) predicts that certain open dissipative systems evolve to a critical state where all energy release statistics display power law distributions for event occurrence, size…1 January, 1999
Differences in morphometry between five populations of black-browed albatrosses (Diomedea melanophrys) and four populations of grey-headed albatrosses (D. chrysostoma) are examined. Two clear groups of black-browed albatrosses are evident, with…1 January, 1999
The marine habitat exploited by black-browed Diomedea melanophrys and grey-headed albatrosses D. chrysostoma breeding at Campbell Island, New Zealand, was studied using satellite telemetry. Data were analysed in relation to…1 January, 1999
In the Southern Ocean white-chinned petrels Procellaria aequinoctialis form the majority of the bird bycatch in longline fisheries. Satellite tracking of breeding birds from the Crozet islands and from South…1 January, 1999
There is an apparent mismatch between the high carbon demand of seals and seabirds breeding on the subantarctic island of South Georgia and the overall low primary production measured in…1 January, 1999
Eight groups of mafic dikes and related high-level stocks cut Triassic accretionary complex and Mesozoic magmatic arc formations on Livingston Island. Some are affected by silicic/sericitic alteration, related to Cretaceous…1 January, 1999 by Eric Wolff
As part of the European Project for Ice Coring in Antarctica, a new deep ice core is being drilled at Dome C. Two electrical methods have been used on the…Read more on Comparison of Holocene electrical records from Dome C and Vostok, Antarctica
1 January, 1999 by Eric Wolff
A snowpit in Coats Land, Antarctica, has been sampled in order to obtain a record of Cd, Cu and Zn covering the period 1923–1986. The snowpit record gives an indication…Read more on Antarctic snow record of cadmium, copper, and zinc content during the twentieth century
1 January, 1999 by Roger Worland, William Block
The site of ice nucleation in the freeze-tolerant, sub-Antarctic beetleHydromedion sparsutumhas been investigated. Ice+bacteria, active at above −2.0°C, were isolated from the guts of beetles and identified as a fluorescentPseudomonasspecies.…1 January, 1999
For activity and survival in extreme terrestrial Antarctic habitats, lithobiontic cyanobacteria depend on key biomolecules for protection against environmental stress and for optimization of growth conditions. Their ability to synthesize…1 January, 1999
HF radar data during equinoctial, small IMF By conditions have enabled the substorm growth phase to be studied in both hemispheres. This has revealed highly conjugate behavior during the substorm…20 May, 1998 by Eric Wolff, John Hall, Robert Mulvaney
Aerosol and fresh snow concentrations have been determined at three coastal Antarctic stations, Dumont d'Urville, Halley, and Neumayer. Model estimates suggest that dry deposition, including that caused by wind pumping,…20 May, 1998 by Eric Wolff
Aerosol black carbon concentrations have been measured between 1992 and 1995 at Halley station using an aethalometer. The complete record is dominated by a number of events of high concentration…20 May, 1998 by Eric Wolff
Aerosol samples have been collected at three stations on the coast of Antarctica. At Dumont d'Urville Station, samples have been collected for 4 years, at Halley Station for 2 years,…Read more on Coastal Antarctic aerosol and snowfall chemistry
1 January, 1998
Management of the mackerel icefish (Champsocephalus gunnari) at South Georgia is complicated by the likelihood of substantial periodic variations in natural mortality rates. These may be associated with increased consumption…1 January, 1998 by Peter Convey, Rod Arnold
Two populations of the world's most southerly diving beetle (Lancetes angusticollis) were studied on sub-Antarctic South Georgia between November 1995 and April 1996. Parallel observations were made on laboratory cultures…