Showing 11923 items
1 January, 2003
U-Pb sensitive high-resolution ion microprobe data together with geochemical and Nd isotope analyses obtained in the basement complex of the Sierra de la Ventana Fold Belt indicate that the Early…1 January, 2003
The semidiurnal tide (SDT) is investigated through comparative analysis of horizontal winds measured at Poker Flat (65degreesN, 147degreesW), Andenes (69degreesN, 16degreesE), Davis (69degreesS, 78degreesE), and Rothera (68degreesS, 69degreesW). At the…1 January, 2003 by Philip Leat, Teal Riley
Rare basaltic volcanic rocks from the northern Antarctic Peninsula (Jason Peninsula) are established as marginally predating a silicic large igneous province, which developed along the proto-Pacific margin of Gondwana. Ar-40-Ar-39…1 January, 2003 by Philip Leat, Teal Riley
Ultramafic lamprophyre (UML) dykes from the Ferrar Province (Pensacola Mountains) of Antarctica preserve trace element and isotope signatures similar to Bouvet volcanic rocks, which are considered to reflect the palaeo…1 January, 2003 by David Vaughan, Hugh Corr
An airborne radio-echo sounding campaign carried out in the upper reaches of Bailey Ice Stream and Slessor Glacier, in Coats Land, East Antarctica, has revealed that tributaries of enhanced flow…Read more on Basal topography and ice flow in the Bailey/Slessor region of East Antarctica
1 January, 2003 by Mark Clilverd
The behavior of high-energy electrons trapped in the Earth's Van Allen radiation belts has been extensively studied, through both experimental and theoretical techniques. While the evidence for whistler induced electron…1 January, 2003
The UV radiation environment on planetary surfaces and within atmospheres is of importance in a wide range of scientific disciplines. Solar UV radiation is a driving force of chemical and…Read more on Solar UV irradiation conditions on the surface of Mars
1 January, 2003 by Howard Roscoe, Jonathan Shanklin, Steve Colwell
Water vapour is a potent greenhouse gas, and the observed increases in water vapour in the stratosphere act to cool it. Possible changes in stratospheric temperatures are important for future…1 January, 2003 by Eric Wolff, Robert Mulvaney
Chloride (Cl-) and sodium (Na+) in ice cores originate mainly from sea salt, and one would thus expect the Cl-/Na+ ratio to reflect the seawater ratio. However, at Dome C,…1 January, 2003 by Dominic Hodgson
A floristic and taxonomic survey was made of the diatom communities of sediments and microbial mats in 66 freshwater and saline lakes and pools in the Larsemann Hills, Rauer Islands…1 January, 2003
The use of stable isotopes to study food webs has increased rapidly, but there are still some uncertainties in their application. We examined the delta(15)N and delta(13)C values of Antarctic…1 January, 2003
[1] The photolysis frequency of NO2, j(NO2), was determined by various instrumental techniques and calculated using a number of radiative transfer models for 4 days in June 1998 at the…1 January, 2003 by Richard Hindmarsh, Richard Hindmarsh
Internal isochronous ice sheet layers, recorded by airborne ice-penetrating radar, were measured along an ice flowline across a large (> I km high) subglacial hill in the foreground of the…1 January, 2003
Our understanding of Lake Vostok, the huge subglacial lake beneath the East Antarctic Ice Sheet, has improved recently through the identification of key physical and chemical interactions between the ice…1 January, 2003 by Dominic Hodgson
Novel transformation products of chlorophyll a incorporating a methyl sulfide group in the substituent at the C-3 position have been identified in Recent sediments from an Antarctic lake.1 January, 2003 by Iain Staniland
This study investigated how female Antarctic fur seals adapt their foraging behavior, over time scales of days, to spatial unpredictability in the distribution of their food. Lactating Antarctic fur seals…1 January, 2003 by Iain Staniland
Female Antarctic fur seals returning ashore after foraging trips were restrained, and fecal material was obtained by introducing approximately one litre of warm water into the animal's colon via the…Read more on An enema method for obtaining fecal material from known individual seals on land
1 January, 2003
The timing and synchronisation of Greenland and Antarctic climate events that occurred during the last glacial period are still under debate, as is the magnitude of temperature change associated with…1 January, 2003 by Hilmar Gudmundsson
During a period of diurnal fluctuations in glacial flow speed, vertical strain was measured with sub-daily temporal resolution on Unteraargletscher, Switzerland. Mean vertical strain in boreholes up to 300-m deep…Read more on Diurnal variations in vertical strain observed in a temperate valley glacier
1 January, 2003 by Hilmar Gudmundsson
The effects of spatial and temporal variations in basal lubrication on the englacial strain rate and surface velocity distribution are investigated with a numerical ice-flow model. General aspects of the…1 January, 2003
This study presents the first direct evidence, based on biochemical analysis of fresh material, that certain benthic foraminifera feed selectively on specific components of seasonally deposited phytodetritus in their natural…1 January, 2003 by Michael Dunn, Philip Trathan
Chinstrap penguins Pygoscelis antarctica are one of the major consumers of Antarctic krill Euphausia superba in the Southern Ocean. To examine their foraging strategy, we studied foraging trip patterns and…1 January, 2003
The land–sea interface, or Coastal Transition Zone (CTZ), is the area that links terrestrial and marine habitats. We use here the definition of [Schaefer, 1972]: “the sea and the land…1 January, 2003 by Geraint Tarling
The diel vertical migration (DVM) and population dynamics of northern krill were investigated in the Clyde Sea over several years using depth-discrete net-sampling and a moored 300 kHz acoustic Doppler…1 January, 2003 by Geraint Tarling
The molting, spawning, and recruitment of northern krill (Meganyctiphanes norvegica) were analyzed over an annual cycle (1999-2000) in the Clyde Sea (west coast of Scotland). Results supported the hypothesis of…1 January, 2003
Earthquake data from the Scotia Arc to early 2002 are reviewed in the light of satellite gravity and other data in order to derive a model for the motion of…1 January, 2003 by Eugene Murphy, Jonathan Watkins, Philip Trathan
Oceanographic data collected to the north of South Georgia were examined for three consecutive summers (1996/97, 1997/98, 1998/99). The results show the existence of a shelf break front during each…1 January, 2003 by Eugene Murphy, Philip Trathan
The data set of Reynolds and Smith [1994] is used to describe temporal variability in sea surface temperature (SST) at South Georgia. Time series analysis indicates that high levels of…1 January, 2003 by Gareth Marshall, John King, John Turner, Thomas Lachlan-Cope
The exceptional sea-ice retreat and advance that occurred in the Bellingshausen Sea, Antarctica during August 1993 was the largest such winter event in this sector of the Antarctic during the…Read more on An exceptional winter sea-ice retreat/advance in the Bellingshausen Sea, Antarctica
1 January, 2003 by Andrew Clarke, Lloyd Peck
Quasi-monthly samples of the Antarctic pectinid bivalve Adamussium colbecki were examined to determine the gametogenic pattern and periodicity. Both female and male gametogenic patterns show a very distinct seasonal development,…1 January, 2003
A conceptual model is proposed where bulk transtension, or local transtension during bulk simple shear (resulting from mantle anisotropy- or lithosphere rheology contrasts), of heterogeneously enriched lithospheric mantle, trigger localised…1 January, 2003
A major new synthesis of ophiolite geochronology and map of global Phanerozoic distribution indicates that previously noted pulses of ophiolite obduction can be linked to superplume-related tectonism. A marked cyclicity…Read more on Ophiolite obduction pulses as a proxy indicator of superplume events?
1 January, 2003 by Dominic Hodgson, David Vaughan, Gareth Marshall, John King, John Turner, Robert Mulvaney
The Intergovernmental Panel on Climate Change (IPCC) confirmed that mean global warming was 0.6 +/- 0.2degreesC during the 20th century and cited anthropogenic increases in greenhouse gases as the likely…Read more on Recent rapid regional climate warming on the Antarctic Peninsula
1 January, 2003 by Andy Smith, David Vaughan
The acoustic impedance of the subglacial material beneath 7.2 km profiles on four ice streams in Antarctica has been measured using a seismic technique. The ice streams span a wide…Read more on Acoustic impedance and basal shear stress beneath four Antarctic ice streams
1 January, 2003 by Dominic Hodgson
The water chemistry of lake systems on the edge of the Antarctic continent responds quickly to changes in the moisture balance. This is expressed as increasing salinity and decreasing lake…1 January, 2003 by Roger Worland
The FT-Raman spectra of an Antarctic endolith from the LTER site at Lake Hoare are reported. The specimen provides an unusual occurrence of endolithic colonization of an igneous rock substratum,…Read more on FT-Raman spectroscopic analysis of an Antarctic endolith
1 January, 2003 by Jonathan Watkins
This paper presents Maximum Entropy (MaxEnt) reconstructions of krill distribution and estimates of mean krill density within two survey boxes (dimensions 80 km x 100 km) north of South Georgia.…1 January, 2003 by Peter Ward
During four summer seasons mesozooplankton community composition and structure in relation to water mass distribution were investigated along a 735-km transect running across the Antarctic Circumpolar Current (ACC) to the…1 January, 2003
Tracks made in minerals by the electronic stopping Of uranium fission fragments provide a modern geological dating tool, and are believed also to yield specific information on the low-temperature thermal…1 January, 2003
The Antarctic Peninsula is the largest of ~ twelve micro-continental fragments between southern South America, East Antarctica, and New Zealand. Their original positions and movement history following Gondwana breakup are…1 January, 2003 by Eric Wolff
To an observer from space, the growth and retreat of the white ring of sea ice around Antarctica would be one of the clearest signs that Earth's climate varies on…1 January, 2003 by Eric Wolff
The sea ice surface, not open water, is the dominant source of sea salt to aerosol and ice cores in coastal Antarctica. Here, we show that it may also form…Read more on An ice core indicator of Antarctic sea ice production?
1 January, 2003
1] Lower thermospheric and upper mesospheric rotational temperatures have been derived from ground-based measurements of the O-2(0-1) and OH(6-2) nightglow emissions over Resolute Bay, Canada ( 74.68degreesN, 94.90degreesW) and OH(4-2)…1 January, 2003 by Jonathan Watkins
Acoustic surveys for biomass estimation require accurate identification of echoes from the target species. In one objective technique for identifying Antarctic krill, the difference between mean volume-backscattering strength at two…1 January, 2003
We welcome the development of the debate about structures at the surge-type glacier Kongsvegen, Svalbard. Our paper (Woodward et al., 2002) tested a number of hypotheses proposed in the literature…1 January, 2003 by Roger Worland, William Block
Cold tolerant polar terrestrial arthropods have evolved a range of survival strategies which enable them to survive the most extreme environmental conditions (cold and drought) they are likely to encounter.…Read more on Desiccation stress at sub-zero temperatures in polar terrestrial arthropods
1 January, 2003 by Richard Horne
[1] Recently, Robinson et al. [2000] presented a brief report on the artificial generation of ULF waves by high power ionospheric modification and their subsequent detection by the Fast Auroral…1 January, 2003
The diet and breeding performance of Grey-headed Albatrosses Thalassarche chrysostoma and Black-browed Albatrosses Diomedea melanophris breeding at Bird Island, South Georgia, were studied simultaneously during the chick-rearing period between 1996…1 January, 2003 by Paul Rodhouse, Philip Trathan
Cephalopods play an important role in the diet of many predators of the Southern Ocean. We investigated the cephalopod component of the diet of the wandering albatross, during breeding at…1 January, 2003 by Andrew Wood, Philip Trathan
The foraging areas and diets of the grey-headed albatross Thalassarche chrysostoma and wandering albatross Diomedea exulans were studied in March/April 2000 at Bird Island, South Georgia, during their respective chick-rearing…1 January, 2003
Results of TIMS, SIMS and SEM analyses show that zircon and monazite in a high-grade paragneiss of the Ruhla Crystalline Complex, central Germany, were formed and/or altered during different stages…1 January, 2003
The classical model of trough mouth fan (TMF) formation was developed in the Polar North Atlantic to explain large submarine fans situated in front of bathymetric troughs that extend across…Read more on Palaeo-ice streams, trough mouth fans and high-latitude continental slope sedimentation
1 January, 2003
Discovery of at least 100 subglacial lakes beneath the vast East Antarctic Ice Sheet has focused international attention on the challenges presented by the way we conduct science in such…Read more on An International Plan for Antarctic Subglacial Lake Exploration
31 December, 2002
Recent work has suggested that in highly correlated systems, such as sandpiles, turbulent fluids, ignited trees in forest fires and magnetization in a ferromagnet close to a critical point, the…Read more on Extremum statistics: a framework for data analysis
31 December, 2002
The study of the robust features of the magnetosphere is motivated both by new “whole system” approaches, and by the idea of “space climate” as opposed to “space weather”. We…1 December, 2002 by Eric Wolff
This paper discusses the chemical composition of frost flowers and their accompanying slush layers and the evidence for their role as a salt source in processes important to atmospheric chemistry…Read more on Frost flowers – implications for tropospheric chemistry and ice core interpretation
1 December, 2002 by Gareth Marshall, John King, John Turner, Steve Colwell
During the Austral summer of 2001/02 exceptionally heavy sea ice conditions were experienced over the eastern Weddell Sea. Satellite microwave imagery showed that large negative (positive) ice anomalies were present…30 November, 2002 by Michael Pinnock
This study investigates further the relationship between regions of the magnetosphere and the characteristics of HF radar Doppler spectra recorded in the ionospheric projection of those regions. It builds on…Read more on Influence of magnetospheric processes on winter HF radar spectra characteristics
30 November, 2002 by Michael Pinnock
The HF radars of the Super Dual Auroral Radar Network (SuperDARN) provide measurements of the E ×B drift of ionospheric plasma over extended regions of the high-latitude ionosphere. We have…1 November, 2002 by Jonathan Watkins
Acoustic surveys to estimate krill biomass require that the sound backscattered by krill can be identified and distinguished from all other types of backscatter. Sampling acoustic targets with nets to…Read more on Verification of the acoustic techniques used to identify Antarctic krill
31 October, 2002 by Michael Pinnock
The geomagnetic conditions were moderately disturbed (Kp = 2) during magnetic midnight on 10 December 1999, when the Tasman International Geospace Environment Radar (TIGER), a Southern Hemisphere HF SuperDARN radar,…1 October, 2002 by Gareth Chisham, Mervyn Freeman, Michael Pinnock
[1] We present measurements of the convection electric field in the dayside ionosphere during extended intervals when the interplanetary magnetic field (IMF) has a negative Bz component and a significant…1 October, 2002 by Mark Clilverd
Wave-particle interactions driven by whistler mode waves in the inner Van Allan belt is an important loss process for the energetic electrons found in this region. In this paper we…1 October, 2002 by Eric Wolff, Robert Mulvaney
A detailed record of non-sea-salt calcium, a proxy for dust, and sea-salt sodium, a proxy for sea salt, covering the last 45 kyr is presented. It shows that in the…1 October, 2002 by Anna Jones, Eric Wolff
Experimental observations have shown photochemical production in the upper layers of firn. We use a modeling approach for Antarctica in summer, calculating the actinic flux in snowpack, and estimating NOX…31 July, 2002 by Richard Horne
We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES) to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies…1 July, 2002 by Martin Collins
The systematics of the deep-sea cirrate octopod genus Opisthoteuthis Verrill in the Atlantic Ocean is reviewed. Comparisons, based on examination of all extant type material and new, reported and unreported…1 July, 2002 by Martin Collins
Small benthic octopodids of the genus Pareledone are commonly found around the shelf area of the sub-Antarctic island South Georgia but little is known about their biology. During three consecutive…Read more on Distribution of Pareledone spp. (Octopodidae: Eledoninae) around South Georgia
1 June, 2002 by John King
The surface energy budget of coastal polynyas in the southern Weddell Sea has been evaluated for the period 1992–1998 using a combination of satellite observations, meteorological data, and simple physical…Read more on Coastal polynyas in the southern Weddell Sea: variability of the surface energy budget
1 May, 2002
[1] Statistical properties of the interplanetary magnetic field fluctuations can provide an important insight into the solar wind turbulent cascade. Recently, analysis of the Probability Density Functions (PDF) of the…Read more on Finite size scaling in the solar wind magnetic field energy density as seen by WIND
30 April, 2002
Observations made by the DMSP 1710 satellite during the recovery phase from geomagnetic disturbances in June 1991 show regions of He+ dominance around 830 km altitude at 09:00 MLT. These…1 April, 2002 by Claire Waluda, Paul Rodhouse, Philip Trathan
Marine fisheries provide around 20% of animal protein consumed by man worldwide, but ineffective management can lead to commercial extinction of exploited stocks. Fisheries that overlap nationally controlled and high…31 January, 2002 by Gareth Chisham, Michael Pinnock
The HF radar Doppler spectral width boundary (SWB) in the cusp represents a very good proxy for the equatorward edge of cusp ion precipitation in the dayside ionosphere. For intervals…31 January, 2002 by Gareth Chisham, Michael Pinnock
Global convection mapping using line-of-sight Doppler velocity data from the Super Dual Auroral Radar Network (SuperDARN) is now an accepted method of imaging high-latitude ionospheric convection. This mapping process requires…1 January, 2002 by Mervyn Freeman
[1] We analyze the power spectrum of the line-of-sight ionospheric velocity measured by the SuperDARN CUTLASS Finland radar and of contemporaneous magnetic field perturbations measured by nearby IMAGE magnetometers. The…1 January, 2002 by Paul Rodhouse
A total of 211 juvenile and paralarval squid were collected on five research cruises made in the Scotia Sea region during the austral summer (1996-1999). These included specimens of Alluroteuthis…Read more on Distribution of juvenile squid in the Scotia Sea in relation to regional oceanography
1 January, 2002
Data from a monostatic acoustic radar operating at British Antarctic Survey's Halley station on a coastal Antarctic ice shelf show a band of small target echoes at an altitude of…1 January, 2002
Plasma leptin levels were determined in 8 lactating female and 20 pup Antarctic fur seals (Arctocephalus ga:ella) during fasting periods of normal duration. Plasma leptin levels ranged from 1.35-3.19 ng.ml(-1)…1 January, 2002
We used the otoliths from a sample of Dissostichus eleginoides pre-recruits, whose length density was distinctly polymodal, to see whether ages estimated by reading otoliths were congruent with the length…Read more on Length-at-age in juvenile Patagonian toothfish (Dissostichus eleginoides)
1 January, 2002
The overwintering success of Euphausia superba is a key factor that dictates population size, but there is uncertainty over how they cope with the scarcity of pelagic food. Both nonfeeding…1 January, 2002 by Iain Staniland
The Antarctic fur seal (Arctocephalus gazella) and macaroni penguin (Eudyptes chrysolophus) are sympatric top predators that occur in the Southern Ocean around South Georgia where they are, respectively, the main…Read more on Are penguins and seals in competition for Antarctic krill at South Georgia?
1 January, 2002
In marine ecosystems, characterisation of the foraging areas and habitats of predators is a key factor in interpreting their ecological role, We studied the foraging areas of the macaroni penguin…1 January, 2002
Understanding how parental expenditure reflects food availability and influences reproductive output is a key part of studies of breeding performance. Provisioning behaviour is an important aspect of parental expenditure. We…Read more on Provisioning behaviour of macaroni penguins Eudyptes chrysolophus
1 January, 2002 by David Barnes
Two clades of marine bryozoans, cyclostomes and cheilostomes, exemplify the benefits of applying a multidisciplinary approach to the interpretation of long-term evolutionary patterns. The cyclostome bryozoans were dominant in the…1 January, 2002 by David Barnes
There is a complex and dynamic interrelationhip between hermit crabs, humans and the coastal environment. Hermit crab homes (shells) are often hard to come by, but humans are helping out…1 January, 2002 by David Barnes
Colonization by alien species poses one of the greatest threats to global biodiversity1. Here I investigate the colonization by marine organisms of drift debris deposited on the shores of 30…1 January, 2002 by David Barnes
Many organisms overlap in their use of resources in space and time. Where and when resources are restricted, species must compete for them. Living space, often a critical resource controlling…Read more on Polarization of competition increases with latitude
1 January, 2002 by David Barnes
1. Resources vary critically in space and time so the ability of animals to utilize them necessarily does so in sympathy. For hermit crabs in coastal SW Madagascar, a critical…1 January, 2002 by David Barnes
Populations of the echinoid Paracentrotus lividus have undergone spectacular population fluctuations over the last 40 yr at Lough Hyne, SW Ireland, Censuses in 2000 and 2001, reported here, show no…