Showing 11500 items
1 January, 2004
The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR…1 January, 2004
We describe how the exploration of the Martian environment would be considerably enhanced through the use of Raman spectroscopy. Furthermore, Raman spectroscopy is particularly suited for both mineralogical analysis of…Read more on The role of Raman spectroscopy as an astrobiological tool in the exploration of Mars
1 January, 2004
We have analyzed ELF-VLF receiver and search coil magnetometer data from five Antarctic stations from 1998 and 1999 to study quasiperiodic emissions (QPs) and periodic emissions (PEs), which occur as…1 January, 2004
Airglow imager and dynasonde/imaging Doppler interferometer (IDI) radar wind measurements at Halley Station, Antarctica (75.6degreesS, 26.6degreesW) have been used to estimate the seasonal variation of the vertical fluxes of horizontal…1 January, 2004
Airglow imager and dynasonde/IDI radar wind measurements at Halley Station, Antarctica (76degreesS, 27degreesW) have been used to estimate the diurnal variation of the vertical fluxes of horizontal momentum carried by…Read more on Tidal modulation of the gravity-wave momentum flux in the Antarctic mesosphere
1 January, 2004 by Jaume Forcada
Line-transect estimators were developed to assess abundance of coastal dolphins Tursiops truncatus and Stenella coeruleoalba encountered in low densities during aerial sighting surveys. The analysis improved on conventional approaches by…1 January, 2004 by Andrew Clarke, Lloyd Peck
Seasonal changes in protein and nitrogen metabolism have not previously been reported in any Antarctic suspension-feeding species that ceases feeding for extended periods in winter. To provide comparison with data…1 January, 2004 by Gareth Chisham, Mervyn Freeman
The Doppler spectral width of backscatter from the SuperDARN HF radars has been routinely used to identify the ionospheric cusp. The probability distribution of spectral width values has been described…1 January, 2004 by Mervyn Freeman, Simon Morley
A minimal model for the evolution of the global dynamical state of the magnetotail during the substorm has been developed, involving only three simple rules and one free parameter D-the…1 January, 2004 by Claus-Dieter Hillenbrand
Two sediment cores from the deep-sea Murray Canyons area, south of Kangaroo Island, Australia were investigated for quantity and composition of terrigenous material. Spanning the last 175 ka, terrigenous matter…1 January, 2004
In most seabird species incubation shifts shorten when hatching approaches, a behavioural response allowing the chick to be fed soon after hatching. Three mechanisms have been proposed to explain these…1 January, 2004
Northern giant petrels (Macronectes halli) are among the largest and most sexually size dimorphic species of seabirds, with females being only 80% the mass of males. Both sexes scavenge on…Read more on Sexual size dimorphism in northern giant petrels: ecological correlates and scaling
1 January, 2004 by Lloyd Peck
Spermatogenesis, oogenesis and fecundity are described and the gonad index calculated for 10 individuals from each month using histological and image analysis techniques for the Antarctic brittle star Ophionotus victoriae…1 January, 2004
The metabolic rate of moulting macaroni penguins Eudyptes chrysolophus was investigated using three techniques in order to test two hypotheses concerning the energetic cost of the moult fast in penguins.…Read more on Energetics of the moult fast in female macaroni penguins Eudyptes chrysolophus
1 January, 2004
We tested the hypothesis that implanted data loggers have no effect on the survival, breeding success and behaviour of macaroni penguins Eudyptes chrysolophus . Seventy penguins were implanted with heart…Read more on Effects of long-term implanted data loggers on macaroni penguins Eudyptes chrysolophus
1 January, 2004
Shortening of telomeres, specific nucleotide repeats that cap eukaryotic chromosomes, is thought to play an important role in cellular and organismal senescence. We examined telomere dynamics in two long-lived seabirds,…Read more on Telomere loss in relation to age and early environment in long-lived birds
1 January, 2004 by Alistair Crame
Fragments of large, bilamellar aspidostomatid bryozoan colonies occur in Early Miocene glaciomarine sedimentary sequences of the Cape Melville Formation, King George Island, South Shetland Islands, West Antarctica. Investigation of the…1 January, 2004
15 years of weekly Antarctic ice extent and 10 m winds from numerical meteorological reanalyses have been used to test the hypothesis that the Antarctic final winter ice extent (FWE)…1 January, 2004
During some El Nino events Rossby wave trains (RWT) are observed to strongly modulate the seasonal atmospheric circulation of the South Pacific extratropics in the austral winter and spring. Here…1 January, 2004 by Roger Worland, Peter Convey
Population densities of the Collembola Cryptopygus antarcticus and Friesea grisea were compared in two maritime Antarctic habitats with different moisture availability. C. antarcticus was absent from the drier rock platform…1 January, 2004
The relative role of the atmosphere, oceans and cryosphere in contributing towards middle Pliocene warmth (ca 3 Ma BP) is investigated using the HadCM3 coupled ocean-atmosphere general circulation model. The…Read more on Modelling Pliocene warmth: contribution of atmosphere, oceans and cryosphere
1 January, 2004
This paper describes the results from a new palaeoclimate modelling exercise for the Early Cretaceous (Barremian) focussed on the Weald (SE England), using a Limited Area Numerical Climate Model (LAM).…Read more on Cretaceous (Wealden) climates: a modelling perspective
1 January, 2004 by Robert Larter
The analysis of the morphology and stratigraphy of the Antarctic Peninsula Pacific margin offshore from Adelaide Island shows 3 main evolutionary intervals, from the Late Miocene to the recent which…1 January, 2004 by Robert Larter
A Fossil Mounded Sedimentary Body (MB) has been identified in the Miocene sedimentary record on the central continental rise west of Adelaide Island, Antarctic Peninsula, using multichannel seismic reflection profiles.…1 January, 2004 by Jonathan Watkins, Philip Trathan
Following an assessment of Antarctic krill (Euphausia superba) in the Scotia Sea, CCAMLR established a precautionary catch limit of 4 million tonnes and further adopted 15 small-scale management units (SSMUs).…1 January, 2004 by Jonathan Watkins, Philip Trathan
In January and February 2000, a collaborative survey designed to assess the biomass of Antarctic krill across the Scotia Sea was conducted aboard research vessels from Japan, Russia, the UK…1 January, 2004 by Richard Hindmarsh, Richard Hindmarsh
A computational analysis of the accuracy of different approximations to the Stokes equations for momentum balance used in ice sheet modeling is performed by solving a particular tractable form of…1 January, 2004 by Richard Hindmarsh, Richard Hindmarsh
The shallow-ice approximation is used to analyse the normal-mode stability of long-wavelength, thermally coupled, free-surface flows of glaciers and ice sheets along infinite flow sections. The viscosity of the ice…1 January, 2004 by Dominic Hodgson
To compile reference data for palaeolimnological studies using fossil pigments, we examined the extent to which environmental variables, gross morphology and species composition influence the modern pigment content of in…1 January, 2004
Recent genetic studies of natural populations have shown that heterozygosity and other genetic estimates of parental relatedness correlate with a wide variety of fitness traits, from juvenile survival and parasite…1 January, 2004 by Eugene Murphy
Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC)…Read more on Advection, krill, and Antarctic marine ecosystems
1 January, 2004 by Robert Mulvaney
This paper presents an overview of firn accumulation in Dronning Maud Land (DML), Antarctica, over the past 1000 years. It is based on a chronology established with dated volcanogenic horizons…1 January, 2004
Chlorophyll-a (Chl-a) concentrations in surface waters were measured at 137 hydrographic stations occupied by four research vessels participating in the CCAMLR 2000 Survey and the values were compared to estimates…1 January, 2004
During January and February 2000 four research vessels, from Russia, the UK, Japan, and the United States, conducted an oceanographic survey with 137 hydrographic stations within the Scotia Sea and…1 January, 2004
Zoroaster fulgens is a slope-dwelling seastar species that is distributed throughout the Atlantic Ocean. Studies into the population structure and systematics of marine animals have increasingly found that species with…1 January, 2004
Fatty acid biomarkers were used to examine the diet of deep-sea holothurians. We collected 3 species from the Porcupine Seabight and Porcupine Abyssal Plain, NE Atlantic, between 800 and 4850…1 January, 2004 by David Pearce, Kevin Hughes, Thomas Lachlan-Cope
This study used PCR-based molecular biological identification techniques to examine the biodiversity of air sampled over Rothera Point (Antarctic Peninsula). 16S rDNA fragments of 132 clones were sequenced and identified…Read more on A preliminary study of airborne microbial biodiversity over peninsular Antarctica
1 January, 2004 by Kevin Hughes
Despite Antarctica being the largest pristine wilderness on Earth, many coastal Antarctic research stations release untreated sewage waste into the marine environment, which may have negative effects on local wildlife.…1 January, 2004 by Kevin Hughes
Human faecal waste has been discarded at inland Antarctic sites for over 100 years, but little is known about the long-term survival of faecal microorganisms in the Antarctic terrestrial environment…Read more on Long-term survival of human faecal microorganisms on the Antarctic Peninsula
1 January, 2004 by Kevin Hughes
This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste…1 January, 2004 by Simon Morley
We estimated fusion frequency with respect to coancestry in the bryozoan Celleporella hyalina, whose briefly planktonic sexually produced larvae settle on algal substrata and proceed to form encrusting colonies by…Read more on Kin or self-recognition? Colonial fusibility of the bryozoan Celleporella hyalina
1 January, 2004 by Teal Riley
Rhyolitic volcanism along the proto-Pacific margin of Gondwana occurred at intervals throughout the Jurassic. Silicic melt generation has been interpreted as a result of interaction between mantle plumes and subduction…1 January, 2004 by Adrian Jenkins
Introduction The continental shelf environment of the Amundsen and Bellingshausen seas differs markedly from that of the other circumpolar seas, where water temperatures are close to the surface freezing point…Read more on Oceanographic observations at the Amundsen shelf break
1 January, 2004 by Adrian Jenkins, Keith Nicholls
[1] The ocean cavity beneath Filchner-Ronne Ice Shelf is observed to respond to the seasonal cycle of water mass production on the continental shelf of the southern Weddell Sea. Here…1 January, 2004 by Eugene Murphy, Jaume Forcada, Philip Trathan
The dynamics of leopard seat Hydrurga leptonyx abundance and residency were investigated both within and between years at Bird Island, South Georgia, using observations of tagged and untagged individuals. Seals…1 January, 2004 by Kevin Newsham
Amino acids constitute one of the largest inputs of organic nitrogen (N) to most polar soils and have been hypothesized to be important in regulating vegetational succession and productivity in…Read more on Rapid amino acid cycling in arctic and antarctic soils
1 January, 2004 by Mark Clilverd
There have been reports in the literature that spaced-antenna MF radars may provide a source of data on Polar Mesospheric Summer Echoes (PMSE). Even though the expected scatter from PMSE…Read more on An alternative explanation of PMSE-like scatter in MF radar data
1 January, 2004 by Roger Worland
Antioxidant enzymes, total glutathione (GSH), and ascorbic acid (ASA) were determined in whole body homogenates of nondiapausing larvae, diapausing larvae during the diapausing period (October, December, and February), and in…1 January, 2004 by Howard Roscoe
Frost flowers grow on newly-formed sea ice from a saturated water vapour layer. They provide a large effective surface area and a reservoir of sea salt ions in the liquid…1 January, 2004
A multi-ship, multi-national survey to assess the acoustic biomass of Antarctic krill across the Scotia Sea was undertaken in January and February 2000. In addition, a total of 135 Rectangular…1 January, 2004
The age of firn air in Antarctica at pore close-off depth is only known for a few specific sites where firn air has been sampled for analyses. We present a…Read more on Model calculations of the age of firn air across the Antarctic continent
1 January, 2004 by Jonathan Watkins
Salp abundance and length frequency were measured during the large-scale CCAMLR 2000 Survey conducted in the Atlantic Sector of the Southern Ocean in the 1999/2000 season. Results from regional surveys…Read more on Salp distribution and size composition in the Atlantic sector of the Southern Ocean
1 January, 2004 by Andy Smith, Ed King
Seismic data from Rutford Ice Stream, West Antarctica show high amplitude, reversed-polarity reflections from parts of the bed. Only interfaces between ice and water, or between water and sediment have…1 January, 2004 by David Vaughan, John King
Redistribution of snow by the wind can drive spatial and temporal variations in snow accumulation that may affect the reconstruction of paleoclimate records from ice cores. In this paper we…Read more on Wind-borne redistribution of snow across an Antarctic ice rise
1 January, 2004 by Mark Belchier
Notothenia rossii was the first target species in Southern Ocean fisheries. The species was already heavily fished at the beginning of the 1970s. The closure of the fishery for this…1 January, 2004
During the austral summer of 2002, a large and persistent phytoplankton bloom was detected with SeaWiFS imagery in the Georgia Basin to the north-west of South Georgia, while waters to…1 January, 2004 by Peter Ward
SeaWiFS was used to examine the spatial and temporal distribution of chlorophyll-a (chl-a) concentrations around the island of South Georgia during four summers between October 1997 and March 2001. A…1 January, 2004 by Mai Mai Lam
[1] Traveling convection vortices (TCVs) are a powerful tool for probing the nature of the coupling between the solar wind, the magnetosphere, and the ionosphere. There is no reliable model…Read more on A test of the magnetospheric source of travelling convection vortices
1 January, 2004 by Robert Larter
Marine geoscientists from the British Antarctic Survey BAS) have carried out a wide range of seismic and sonar investigations over the past eighteen years in the sector of the Southern…1 January, 2004 by Peter Convey
We describe the application of molecular biological techniques to estimate eukaryotic diversity (primarily fungi, algae, and protists) in Antarctic soils across a latitudinal and environmental gradient between approximately 60 and…Read more on Molecular analysis of geographic patterns of eukaryotic diversity in Antarctic soils
1 January, 2004
1. Bacterioplankton production was measured in the water columns of two ultra-oligotrophic, freshwater Antarctic lakes (Crooked Lake and Lake Druzhby) during an annual cycle. In both lakes bacterial production, measured…Read more on Bacterioplankton production in freshwater Antarctic lakes
1 January, 2004
The azooxanthellate scleractinian coral Lophelia pertusa has a near-cosmopolitan distribution, with a main depth distribution between 200 and 1000 m. In the northeast Atlantic it is the main framework-building species,…1 January, 2004
Lopheliapertusa and Madrepora oculata are azooxanthellate corals with nearly cosmopolitan distributions. They form cold-water reefs in the upper bathyal zone on continental margins and offshore banks [A.D. Rogers, Int. Rev.…Read more on A deep-sea slant on the molecular phylogeny of the Scleractinia
1 January, 2004 by Philip Leat, Robert Larter
The intra-oceanic South Sandwich subduction system is distinctive in having a narrow slab with slab edges at its northern and southern ends. We present new geochemical data to investigate magma…1 January, 2004 by Hilmar Gudmundsson
The reaction of alpine glaciers to shifts in the equilibrium line altitude (ELA) is calculated by using a two-dimensional numerical model to solve the full equations for the velocity and…Read more on On estimating length fluctuations of glaciers caused by changes in climatic forcing
1 January, 2004 by Katrin Linse
Agassiz trawl, epibenthic sledge and large box core samples were made in the Scotia and northern Weddell Seas during the 2002 ANDEEP expeditions with R.V. Polarstern at 21 locations (774-6348…1 January, 2004
A ubiquitous feature of the high latitude ocean is the occurrence of convective clouds that are organized into two-dimensional structures known as roll clouds or cloud streets. In this paper,…Read more on A high-resolution simulation of convective roll clouds during a cold-air outbreak
1 January, 2004
The opening of Southern Ocean gateways was critical to the formation of the Antarctic Circumpolar Current and may have led to Cenozoic global cooling and Antarctic glaciation. Drake Passage was…Read more on Shackleton Fracture Zone: no barrier to early circumpolar ocean circulation
1 January, 2004
The diet and reproductive performance of two sympatric penguin species were studied at Signy Island, South Orkney Islands between 1997 and 2001. Each year, Adelie (Pygoscelis adeliae) and chinstrap (P.…1 January, 2004
A series of 26 meteorological rockets ("falling spheres,'' FS) were launched in January and February 1998 from the Antarctic research station Rothera (68degreesS, 68degreesW). These flights gave densities and temperatures…Read more on Temperatures and horizontal winds in the Antarctic summer mesosphere
1 January, 2004 by Peter Convey
Ameronothroid mites, including Ameronothridae, Fortuyniidae and Selenoribatidae, are unique among the Oribatida through having a global distribution from the tropics to the poles, and occupying a diversity of habitats including…Read more on Latitudinal variation in habitat specificity of ameronothrid mites (Oribatida)
1 January, 2004 by Gareth Marshall, John King, John Turner, Thomas Lachlan-Cope
We demonstrate that recent observed trends in the annual and austral summer Southern Hemisphere Annular Mode (SAM) are unlikely to be due to internal climate variability, since they exceed any…Read more on Causes of exceptional atmospheric circulation changes in the Southern Hemisphere
1 January, 2004
The distribution and density of the Amazon's two contrasting endemic dolphins-boto, or Amazon river dolphin, Inia geoffrensis, and tucuxi, Sotalia fluviatilis-were examined on two adjoining large rivers in western Brazil.…1 January, 2004
The size and structure of a community of Amazon river dolphins or botos, Inia geoffrensis (de Blainville, 1817), was investigated using boat surveys and long-term observations of recognisable animals. Year-round,…1 January, 2004
Habitat use by the boto, or Amazon river dolphin Inia geoffrensis, was investigated in and around the Mamiraua Reserve, Brazil. Largely forested with numerous channels and lakes, Mamiraua comprises a…1 January, 2004 by John Turner, Thomas Lachlan-Cope
Intermittent atmospheric blocking-high activity in the South Tasman Sea is shown to play a key role in delivering substantial snowfall as far south as at least 75degreesS on the central…1 January, 2004 by Simeon Hill
In stock assessments of short-lived species, De Lury depletion models are commonly applied in which commercial catches and changing catch rates are used to estimate resource abundance. These methods are…1 January, 2004
An extensive variety of instruments, including Geotail, DMSP F11, SuperDARN, and IMP-8, were monitoring the dayside magnetosphere and ionosphere between 14:00 and 18:00 UT on 18 January 1999. The location…1 January, 2004 by Mark Clilverd
This paper discusses the use of ground magnetometer data to derive plasma mass density profiles of the dayside plasmapause region with spatial and temporal resolution in the range 0.15-0.4 R-E…Read more on Monitoring the plasmapause using geomagnetic field line resonances
1 January, 2004 by Andrew Clarke, John King, Michael Meredith
[ 1] A year-round sequence of hydrographic casts is used to trace the evolution of the upper ocean waters in Marguerite Bay, western Antarctic Peninsula (wAP), between 1998 and 2002.…1 January, 2004 by Richard Horne
We analyze wave and particle data from the CRRES satellite to determine the variability of plasmaspheric hiss (0.1 < f < 2 kHz) with respect to substorm activity as measured…1 January, 2004
The Himalia Ridge Formation (Fossil Bluff Group), Alexander Island is a 2.2-km-thick sequence of Upper Jurassic-Lower Cretaceous conglomerates, sandstones and mudstones, derived from an andesitic volcanic arc and deposited in…1 January, 2004
Macaroni Eudyptes chrysolophus and gentoo Pygoscelis papua penguins occur sympatrically at Bird Island (54degrees00'S, 38degrees02'W), South Georgia, and have a similar diet. Macaroni penguins forage at shallower depths and further…1 January, 2004
This study investigated the degree to which the behavior of a predator in the marine environment can be used to indicate the availability of prey. It examined this in Antarctic…1 January, 2004 by Mark Belchier, Simon Morley
The biology of the bigeye grenadier Macrourus holotrachys caught as by-catch in the Patagonian toothfish Dissostichus eleginoides longline fishery conducted around South Georgia was investigated to improve data available for…Read more on The biology of the bigeye grenadier at South Georgia
1 January, 2004 by Robert Mulvaney
Over the period 1972-98 the height of the snow surface at eight Antarctic sites in Palmer Land and on Alexander Island has been measured with respect to fixed points on…Read more on Recent variations in surface mass balance of the Antarctic Peninsula ice sheet
1 January, 2004 by Eugene Murphy, Jonathan Watkins, Sally Thorpe
A coupled physical-biological model analysis was undertaken to examine the seasonal development of the distribution of antarctic krill (Euphausia superba Dana) in the Scotia Sea. The origin and fate of…1 January, 2004 by Eugene Murphy, Michael Meredith, Philip Trathan, Peter Ward, Sally Thorpe
During December 2000 and January 2001 we conducted a high-resolution hydrographic and bioacoustic transect (RRS James Clark Ross cruise 57) that extended across the South Georgia shelf from close to…1 January, 2004
Within the past 7 years, the northern Larsen Ice Shelf has broken up so it is now possible to sample the sea floor that formerly lay beneath it. Box cores…1 January, 2004 by Philip Trathan
Procellariiform seabirds (petrels, albatrosses and shearwaters) forage over thousands of square kilometres for patchily distributed prey resources. While these birds are known for their large olfactory bulbs and excellent sense…Read more on Testing olfactory foraging strategies in an Antarctic seabird assemblage
1 January, 2004 by David Pearce, Kevin Newsham
We tested the preferences of three nematode taxa, Geomonhystera villosa, Plectus spp. and Teratocephalus spp., extracted from moss at Signy Island in the Maritime Antarctic, for two microalgae, three microfungi…Read more on Differing preferences of Antarctic soil nematodes for microbial prey
1 January, 2004 by Keith Nicholls
We report on oceanographic observations made at the northern end of Larsen C Ice Shelf in the western Weddell Sea. It appears that the Larsen C continental shelf is flushed…Read more on Summertime water masses off the northern Larsen C Ice Shelf, Antarctica
1 January, 2004 by Keith Nicholls
[1] Multiyear time series of ocean current and temperatures from beneath Filchner-Ronne Ice Shelf, Antarctica, demonstrate both seasonal and interannual variability. The seasonal signal is visible at all measurement sites,…1 January, 2004 by Keith Makinson, Keith Nicholls
We present oceanographic data from beneath the northern Ronne Ice Shelf. The data were collected during the austral summer of 2002–2003 from four sites located near the ice front in…Read more on Circulation and water masses beneath the northern Ronne Ice Shelf, Antarctica