Found 14112 items
1 January, 1999
A large sample of otoliths from the mackerel icefish (Champsocephalus gunnari) was measured and weighed and their effectiveness as predictors of fish length and fish mass determined. The two measures,…Read more on Otolith and body size relationships in the mackerel icefish (Champsocephalus gunnard)
1 January, 1999
The essential aim of biological sampling is to obtain samples that are representative of the targets under consideration. Sampling in support of in situ target strength studies should be aimed…1 January, 1999
Analyses of size at sexual maturity were undertaken on samples of Patagonian toothfish (Dissostichus eleginoides) caught in the commercial fishery within Subarea 48.3. The results for 1996 indicate that Lm50…Read more on Size at sexual maturity of Patagonian toothfish (Dissostichus eleginoides)
1 January, 1999
1. Bottom trawl surveys on the South Georgia shelf indicate episodic declines in the abundance of the mackerel icefish Champsocephalus gunnari that, since 1990, are not directly attributable to commercial fishing.…1 January, 1999
The sea-surface distribution of four selected fossilizable phytoplankton groups (coccolithophores, diatoms, silicoflagellates and dinoflagellates) has been studied along a transect from Cape Town (34°S) to South Sandwich Islands (57°S) during…1 January, 1999 by Michael Pinnock
On 7 December 1992, a moderate substorm was observed by a variety of satellites and ground-based instruments. Ionospheric flows were monitored near dusk by the Goose Bay HF radar and…1 January, 1999 by Mervyn Freeman
We study an aspect of substorm occurrence during Earth passage of the October 1995 magnetic cloud and the corotating stream overtaking it. The substorms were identified primarily by five latitudinal…1 January, 1999 by Eric Wolff
The calcium (representing dust) concentration record of the last 100,000 years from the Greenland Ice Core Project (GRIP) ice core shows a huge dynamic range (factor>100). The relationship between dust…1 January, 1999
This study examined pituitary sensitivity to exogenous gonadotrophin-releasing hormone (GnRH) in relation to time of year and changes in plasma progesterone, testosterone, luteinising hormone (LH), and follicle-stimulating hormone (FSH) concentrations…1 January, 1999
A 181 m long ice core was drilled at 79°36′51″ S, 45°43′28″ W, near the summit of Berkner Island, Antarctica (886 m a.s.l.). Berkner Island is located between the Filchner…Read more on Density log of a 181 m long ice core from Berkner Island, Antarctica
1 January, 1999
Present radiative transfer methods in physically based energy budget models of snow do not include adequate spectral or directional resolution to deal with the scattering of solar radiation. This paper…Read more on Incorporation of spectral and directional radiative transfer in a snow model
1 January, 1999 by Sandra McInnes, Sandra McInnes
Cryoconite holes, supraglacial ponds and moulins of the Greenland Ice Sheet were surveyed for microbiota and meiofauna. These habitats are colonised by depauperate communities of widespread/cosmopolitan microbes, microalgae, rotifers and…Read more on Tardigrades, and other cryoconite biota, on the Greenland Ice Sheet
1 January, 1999
The thermal sensitivity of mitochondrial function was investigated in the stenothermal Antarctic fish Lepidonotothen nudifrons. State 3 respiration increases with increasing temperature between 0 °C and 18 °C with a Q 10…1 January, 1999
Dinoflagellate cyst analysis has been undertaken on three Kasten cores taken from the Falkland Trough, Scotia Sea and Weddell Sea in the area of the Antarctic Peninsula. Two of these…1 January, 1999
Dinoflagellate cysts have been recovered from six long-term (1–2 yr) sediment trap moorings deployed in the Bellingshausen, Weddell and Scotia seas, Antarctica. These traps, mostly moored near the sea bed…1 January, 1999 by John Turner
Polar mesocyclones are subsynoptic-scale low pressure systems that form over high-latitude oceans in a cold air mass. It is known that these systems can be very vigorous but only relatively…1 January, 1999 by John Turner
Causal mechanisms of mesocyclone and synoptic cyclone characteristics over the Northeast Atlantic and Nordic Seas are investigated using a 2-year database compiled from infrared satellite imagery. A strong seasonality is…1 January, 1999
An objective assessment of maturity in the loliginid squid Loligo gahi was tested using a method developed for L. pealeii utilizing principal component and discriminant analyses. Samples were taken from…1 January, 1999
The upper part of the Jurassic‐Cretaceous Byers Group, exposed on Byers Peninsula in the South Shetland Islands, Antarctica, consists of 1.4 km of non‐marine strata assigned to the Cerro Negro…1 January, 1999 by Richard Hindmarsh, Richard Hindmarsh
Quadrature solutions for temperature fields in the central regions of ice sheets where flow is by internal deformation are presented and compared with numerical computations and the European Ice Sheet…Read more on On the numerical computation of temperature in an ice sheet
1 January, 1999 by Richard Hindmarsh, Richard Hindmarsh
The geomorphological effects of ice sliding over till, internal deformation of till and till sliding over bedrock are considered. Two questions are examined: (1) is the till-sheet flow unstable, i.e.…Read more on Coupled ice–till dynamics and the seeding of drumlins and bedrock forms
1 January, 1999 by Richard Hindmarsh, Richard Hindmarsh
The pore-water signal left behind by a glacier overriding a porous medium is considered. Important processes are infiltration, tracer diffusion, radio-active decay, penetration of freezing fronts and erosion and deposition.…1 January, 1999 by William Block
Hydrologists and ecologists studying tundra ecosystems have worked largely independently, with little cross-fertilization between disciplines. Their disciplines are, however, inextricably linked by a need to understand the dynamics and significance…1 January, 1999 by Adrian Jenkins
Models of ocean circulation beneath ice shelves are driven primarily by the heat and freshwater fluxes that are associated with phase changes at the ice–ocean boundary. Their behavior is therefore…Read more on Modeling Thermodynamic Ice–Ocean Interactions at the Base of an Ice Shelf
1 January, 1999
In the northern Scotia Sea, the main pathway of Circumpolar Deep Water (CPDW) flows north to pass through a deep gap in the North Scotia Ridge before turning east into…1 January, 1999 by John Turner
An overview is presented of the analysis procedures and problems encountered in the FROST reanalysis of weather charts poleward of latitude 50°S carried out in Hobart by the Australian Bureau…Read more on On the Reanalysis of Southern Hemisphere Charts for the FROST Project
1 January, 1999
This paper discusses predicted evolution patterns of present-day changes of ice thickness, surface elevation, and bedrock elevation over the Greenland and Antarctic continents. These were obtained from calculations with dynamic…1 January, 1999
Studies of the Antarctic mesosphere, and its contrasts with the Arctic, are expected to hold the key to improved understanding of the mesopause region and energy and momentum transfer processes…Read more on New initiatives in observing the antarctic mesosphere
1 January, 1999 by Adrian Jenkins
Ice melts when it is in contact with ocean waters that have temperatures above the in situ freezing point. The product is a mixture of meltwater and seawater having properties…1 January, 1999
Mesospheric winds are derived from HF radar observations of meteor echoes at Halley (76°S, 27°W), Antarctica. These meteor echoes are observed within the first range gates of the radar (less…Read more on Mesospheric winds derived from SuperDARN HF radar meteor echoes at Halley, Antarctica
1 January, 1999
The utility of aeromagnetic and other geoscientific compilations on a range of scales, is well established for a wide variety of geological investigations. Aeromagnetic compilations, currently underway for the Antarctic…1 January, 1999
New high-resolution aeromagnetic anomaly data from the central Antarctic Peninsula reveal a magnetic signature typical of a magmatic arc system. Analysis of the new aeromagnetic map, together with susceptibility data…Read more on Interpretation of new aeromagnetic anomaly data from the central Antarctic Peninsula
1 January, 1999 by Anna Jones, Eric Wolff
Understanding the NOy budget at high latitudes is important for our knowledge of present-day clean air chemistry and essential for reliable interpretation of existing ice core nitrate data. However, measurements…Read more on Oxidized nitrogen chemistry and speciation in the Antarctic troposphere
1 January, 1999
Because of the lack of a definitive air link to an international gravity base station, the Antarctic Peninsula gravity network was originally, and still is, tied to the Potsdam gravity…Read more on A new estimate of the adopted gravity value at Rothera Station, Antarctic Peninsula
1 January, 1999
The circum-Antarctic clam Laternula elliptica (King & Broderip 1831) is the largest infaunal bivalve of the Southern Ocean. It mostly lives in water depths of less than 100 m (highest…1 January, 1999 by David Barnes
Sixty specimens of the giant marine isopod Glyptonotus antarcticus Eights, collected from Borge Bay, Signy Island, Antarctica were examined for epizoans. Ten species of cheilostomatid bryozoans were found on the…1 January, 1999 by John King
Measurements of humidity at a height of 4 m were made at Halley Research Station between 1995 and 1997 using a frost point hygrometer. Relative humidities were usually close to…1 January, 1999 by Eric Wolff
In this paper we first summarise major findings of recent atmospheric studies of nitrogen and sulphur species present in the boundary layer of coastal Antarctic regions. We then discuss the…1 January, 1999 by John Turner
The performance of three automatic depression tracking schemes developed by Terry & Atlas (1996), Murray & Simmonds (1991a) and Konig et al. (1993) when applied over one month are assessed.…Read more on An assessment of three automatic depression tracking schemes
1 January, 1999
The early Cretaceous fill of the forearc/intra-arc Byers Basin includes a 600- to 900-m-thick interval of marine slope apron deposits, the President Beaches Formation. This is a predominantly argillaceous succession…1 January, 1999
A prominent volcaniclastic channel sandstone deposited by a landward-flowing sediment gravity flow is described from the Maastrichtian of Snow Hill Island in the northern Larsen Basin. The characteristics of this…Read more on Possible evidence for Late Cretaceous off-axis volcanism in the outer James Ross Basin
1 January, 1999
The Arctic summer mesopause at ∼88 km is the coldest-known place (∼130 K) in the terrestrial atmosphere and is ∼60 K colder in summer than winter. Indirect evidence has suggested…Read more on First in situ temperature measurements at the Antarctic summer mesopause
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 Peter Convey
The continental Antarctic oribatid mite, Maudheimia wilsoni Dalenius, is often found in compact multi-instar aggregations, under stones. These aggregations may persist for several years. Relative abundances of the four juvenile…Read more on Compact aggregation and life-history strategy in a continental Antarctic mite
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…