Showing 11500 items
1 January, 2007
U-Pb detrital zircon geochronology from the upper Cambrian to Devonian part of the Ellsworth Mountains succession, Antarctica, yields dominant late Mesoproterozoic and late Neoproterozoic–Cambrian age populations that are onsistent with…1 January, 2007 by Elaina Ford
Recent advances in the performance of CCD detectors have enabled a high time resolution study of the high latitude upper thermosphere with Fabry-Perot Interferometers(FPIs) to be performed. 10-s integration times…1 January, 2007
The Neogene Meyer Desert Formation, Sirius Group, at Oliver Bluffs in the Transantarctic Mountains, contains a sequence of glacial deposits formed under a wet-based glacial regime. Within this sequence fluvial…1 January, 2007 by Andrew Clarke, Lloyd Peck
Growth rates in Antarctic ectotherms are generally considered to be low in comparison to temperate and tropical species. Food consumption plays a major role in determining animal growth rates, but…1 January, 2007
Growth is a fundamental process within all marine organisms. In soft tissues, growth is primarily achieved by the synthesis and retention of proteins as protein growth. The protein pool (all…Read more on Protein metabolism in marine animals: the underlying mechanism of growth
1 January, 2007 by Sandra McInnes, Sandra McInnes
The preservation of tardigrade eggs and exuviae in Antarctic lake sediments provided an opportunity to assess post-glacial colonisation and Holocene tardigrade dynamics on the southern continent. Tardigrade eggs were recovered…1 January, 2007 by Martin Collins
Natural bioluminescence (that not mechanically stimulated by human intervention) produced by organisms on the seafloor of the northeast Atlantic ocean between 970 and 4,800 m depth was examined using an…1 January, 2007
During the Late Miocene the Mediterranean experienced a period of extreme salinity fluctuations known as the Messinian Salinity Crisis (MSC). The causes of these high amplitude changes in salinity are…Read more on The Mediterranean hydrologic budget from a Late Miocene global climate simulation
1 January, 2007
Despite increasing interest in long-distance migration, the wintering areas, migration corridors, and population mix in winter quarters of most pelagic marine predators are unknown. Here, we present the first study…Read more on Trans-equatorial migration and mixing in the wintering areas of a pelagic seabird
1 January, 2007 by Lloyd Peck
This study reports the first multi-year observations on the reproductive patterns for an Antarctic predator/scavenger, Odontaster validus (Koehler 1912). Seastars were collected monthly from a shallow site (15–20 m depth)…1 January, 2007 by Anna Jones, Eric Wolff, Markus Frey
It has been shown that sunlit snow and ice plays an important role in processing atmospheric species. Photochemical production of a variety of chemicals has recently been reported to occur…Read more on An overview of snow photochemistry: evidence, mechanisms and impacts
1 January, 2007
INTRODUCTION: The potential advantage of including a psychological test battery in the selection process for service in the Antarctic was examined in 348 applicants for employment in Antarctica with the…Read more on Psychological selection of Antarctic personnel: the “SOAP” instrument
1 January, 2007
Foraging behaviour and energy expenditure were measured continuously throughout the chick-rearing period of free-ranging macaroni penguins Eudyptes chrysolophus. These data were integrated with values obtained from the literature on body…Read more on Feeding, fasting and foraging success during chick rearing in macaroni penguins
1 January, 2007 by Mark Clilverd
The equatorial plasma density and composition at L = 2.5 were studied during an extended disturbed interval using field line resonance measurements (yielding plasma mass density), naturally and artificially stimulated…1 January, 2007 by Hilmar Gudmundsson
[1] Surface speeds of Rutford Ice Stream, West Antarctica, are known to vary by around 10–20% (depending on location) with a fortnightly periodicity corresponding to a springneap tidal cycle. The…Read more on Tides and the flow of Rutford Ice Stream, West Antarctica
1 January, 2007 by Richard Phillips
Many seabirds nesting in areas bordering the North Sea have recently experienced large annual variation in breeding success, including reproductive failures in some cases. In contrast, the breeding success of…1 January, 2007 by Roger Worland, Peter Convey
The plasticity of an organism's phenotype may vary spatially and temporally, and across levels of physiological organisation. Given the adaptive value of plasticity in heterogeneous environments, it might be expected…1 January, 2007 by Roger Worland, Peter Convey
The effect of moulting on the cold hardiness of the oribatid mite Alaskozetes antarcticus (Michael) is investigated. Non moulting animals show clear seasonal patterns of cold hardiness with high supercooling…1 January, 2007 by Roger Worland, Peter Convey
Darwin was an early exponent of the importance of ‘occasional means of dispersal’ in accounting for the present-day distribution of plants and animals. This study examined the implications of capture…1 January, 2007 by Roger Worland, Peter Convey
Aerial dispersal has been frequently proposed as a potential mechanism by which polar terrestrial arthropods are transported to, and settle the ice free habitats of Antarctica, but to date there…1 January, 2007 by Adrian Jenkins
In March 2003 several autonomous underwater vehicle (AUV) missions were carried out under sea ice in the western Bellingshausen Sea. Data from the upward-looking acoustic Doppler current profiler (ADCP) on…1 January, 2007 by Victoria Peck
The Pliocene may have been characterized by permanent El Niño–like conditions. Initial modeling studies suggest that this may have contributed to Pliocene warmth. The termination of this state may have…Read more on A permanent El Niño–like state during the Pliocene?
1 January, 2007 by Anna Jones
Surface ozone records from ten polar research stations were investigated for the dependencies of ozone on radiative processes, snow-photochemisty, and synoptic and stratospheric transport. A total of 146 annual data…1 January, 2007
A Rayleigh-scatter lidar has been operated at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) campus (41.7°N, 111.8°W) since August 1993. During the morning of 22 June…Read more on Observations of a noctilucent cloud above Logan, Utah (41.7oN, 111.8oW) in 1995
1 January, 2007
A cumulative total of over 5 years of data from an MF radar situated at Rothera (67°S, 68°W) on the Antarctic Peninsula have been used to derive climatologies of periodic…1 January, 2007 by Sally Thorpe, Simeon Hill
Expansion of the krill fishery in the Scotia Sea – Antarctic Peninsula region beyond the current precautionary catch limit requires the development and assessment of methods for subdividing the regional…1 January, 2007
The stage-specific abundance and egg production rates of Calanus helgolandicus were determined on a near-weekly basis over 2 yr at a 50 m deep station in the SW English Channel…1 January, 2007
The solar wind exhibits scaling typical of intermittent turbulence in the statistics of in situ fluctuations in both the magnetic and velocity fields. Intriguingly, quantities not directly accessed by theories…Read more on On the fractal nature of the magnetic field energy density in the solar wind
1 January, 2007 by Jaume Forcada, Philip Trathan
Much debate surrounds the exact rules that influence mating behaviour, and in particular the selective forces that explain the evolution of female preferences. A key example is the lek paradox,…Read more on Female fur seals show active choice for males that are heterozygous and unrelated
1 January, 2007 by Adrian Jenkins, Paul Holland
In winter, brine rejection from sea ice formation and export in the Weddell Sea, offshore of Filchner-Ronne Ice Shelf (FRIS), leads to the formation of High Salinity Shelf Water (HSSW).…Read more on Validity of the Ice Shelf Water plume concept under Filchner-Ronne Ice Shelf
1 January, 2007 by Paul Holland
The growth (melt) rate of frazil ice is governed by heat transfer away from (towards) the ice crystal, which can be represented by the Nusselt number. We discuss choices for…1 January, 2007 by Adrian Jenkins, Paul Holland
A two-dimensional plume model is used to study the interaction between Filchner-Ronne Ice Shelf, Antarctica and its underlying ocean cavity. Ice Shelf Water (ISW) plumes are initiated by the freshwater…Read more on Ice Shelf Water plume flow beneath Filchner-Ronne Ice Shelf, Antarctica
1 January, 2007 by Kevin Hughes, Melody Clark
Little is known about the effects of hydrocarbons and fuel oil on Antarctic filamentous fungi in the terrestrial Antarctic environment. Growth of fungi and bacteria from soils around Rothera Research…Read more on Tolerance of Antarctic soil fungi to hydrocarbons
1 January, 2007 by Hamish Pritchard
Ice shelves play an important role in determining regional ocean properties and in modulating ice flux from land to sea. Their dynamics are complex, however, and localised rifts and zones…1 January, 2007
Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal vari- ability of calcium (Ca2+, mainly from mineral…1 January, 2007
During high-speed solar wind streams, substorms occur repetitively and relativistic electron fluxes enhance significantly. It has recently been proposed that enhanced dawnside chorus waves lead to the energization of the…1 January, 2007
A two day workshop on Southern Ocean cephalopods was held in Hobart, Tasmania, Australia prior to the triennial 2006 Cephalopod International Advisory Council (CIAC) symposium. The workshop provided a second…1 January, 2007 by Adrian Jenkins
[1] Contrary to popular belief, the melting of floating ice (in the form of ice shelves, icebergs and sea ice) may have a non-zero impact on sea level. This is…1 January, 2007 by Adrian Jenkins
Introduction George VI Ice Shelf, sandwiched between the western coast of Palmer Land and the eastern coast of Alexander Island, is the largest and most studied of the west Antarctic…Read more on Circulation and melting beneath George VI Ice Shelf, Antarctica
1 January, 2007 by Joanne Johnson
We report chemical compositions of authigenic alteration minerals in subglacially erupted hyaloclastite breccias from James Ross Island, Antarctica, which provide a geochemical proxy for paleoenvironment. Analyses of zeolites (phillipsite and…Read more on Zeolite compositions as proxies for eruptive paleoenvironment
1 January, 2007 by Anna Jones
Chemical processes in the troposphere are driven by a combination of factors. Emissions from the Earth’s surface, either natural or anthropogenic, are the primary source of trace gases in the…1 January, 2007 by Eric Wolff
A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage…Read more on Orbital and millennial Antarctic climate variability over the past 800,000 years
1 January, 2007 by Roger Worland
Antioxidant enzymes (CAT, catalase; GPx, selenium nondependent glutathione peroxidase; GST, glutathione-S-transferase; GR, glutathione reductase; DHAR, dehydroascorbate reductase) were determined in the mitochondria of diapausing and non-diapausing larvae and pupae of…1 January, 2007 by David Barnes
How animals are distributed in the world's largest surface environment, the deep sea, is poorly understood. The ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) III cruise…1 January, 2007
We developed new perspectives to identify important questions and to propose approaches for future research on marine food web lipids. They were related to (i) structure and function of lipids,…1 January, 2007
The Milankovitch theory of climate change proposes that glacial–interglacial cycles are driven by changes in summer insolation at high northern latitudes. The timing of climate change in the Southern Hemisphere…1 January, 2007 by Alistair Crame
The Cenomanian-Santonian biostratigraphy of the James Ross Basin, north-eastern Antarctic Peninsula is in need of comprehensive revision. This is being achieved by the systematic re-investigation of a series of key…Read more on Coniacian ammonites from James Ross Island, Antarctica
1 January, 2007 by Fausto Ferraccioli
The Antarctic magnetic anomaly map compiled marine and airborne surveys collected south of 60 degrees S through 1999 and used Magsat data to help fill in the regional gaps between…1 January, 2007
The 2 most common experimental methods used to estimate rates of juvenile growth in marine copepods are the molt rate (MR) method, and the artificial cohort (AC) method. Recently, we…1 January, 2007 by Ed King
We conducted a seismic experiment on polar firn on Adelaide Island, Antarctica. We measured the speed of compressional and shear waves at different depths in the firn by sampling waves…Read more on Use of shear waves to measure Poisson’s ratio in polar firn
1 January, 2007 by Andy Smith, Ed King
We present seismic and radar data from the onset region of Rutford Ice Stream, West Antarctica, which show the form and internal structure of a variety of bed forms beneath…1 January, 2007 by Richard Hindmarsh, Richard Hindmarsh
The largest channels on Mars are the Northwestern Slope Valleys (NSVs) of Tharsis, which have previously been interpreted as the probable erosional trace of catastrophic flooding. It is argued here…Read more on Did ice streams shape the largest channels on Mars?
1 January, 2007
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is bound by its Article II, 3 to follow an ecosystem approach to management. This approach has been extended…Read more on Fisheries in the Southern Ocean: an ecosystem approach
1 January, 2007 by Mai Mai Lam, Nigel Meredith, Richard Horne, Sarah Glauert
We simulate the behaviour of relativistic (976 keV) electrons in the outer radiation belt (3 ≤ L ≤ 7) during the first half of the CRRES mission. We use a…1 January, 2007 by David Vaughan
For the Filchner-Ronne Ice Shelf we have compiled measurements of meteoric ice thickness from many institutions, and several different techniques (e.g. radar and seismic sounding) to produce an improved digital…1 January, 2007 by Claus-Dieter Hillenbrand, James Smith, Joanne Johnson, Robert Larter
The potential for rapid deglaciation, or collapse, of the 2–million–square–kilometer West Antarctic Ice Sheet (WAIS) in response to climate change is one of the most serious environmental threats facing mankind.…Read more on West Antarctic Ice Sheet change since the last glacial period
1 January, 2007 by David Pearce
Antarctic lakes are characterised by simplified, truncated food webs. The lakes range from freshwater to hypersaline with a continuum of physical and chemical conditions that offer a natural laboratory in…Read more on The biodiversity and ecology of Antarctic lakes: models for evolution
1 January, 2007 by Nigel Meredith
In the first part of this study of the substorm of March 12, 1991, the space-time structure of substrorm disturbance and dynamics of auroral ions were considered. This second part…1 January, 2007 by Nigel Meredith
The substorm on March 12, 1991 is studied using the data of ground-based network of magnetometers, all-sky cameras and TV recordings of aurora, and measurements of particle fluxes and magnetic…1 January, 2007
Based on observed atmospheric carbon dioxide (CO2) concentration and an inverse method, we estimate that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 petagrams…Read more on Saturation of the Southern Ocean CO2 sink due to recent climate change
1 January, 2007 by Philip Leat, Robert Larter
Protector Shoal, the northernmost and most silicic volcano of the South Sandwich arc, erupted dacite–rhyolite pumice in 1962. We report geochemical data for a new suite of samples dredged from…1 January, 2007 by Richard Hindmarsh, Richard Hindmarsh
Variations in the depth of radar-detectable englacial layers (isochrones) are commonly used to assess past variability in accumulation rates, but little is known about the effect of internal and basal…Read more on Three-dimensional flow influences on radar layer stratigraphy
1 January, 2007 by Katrin Linse
The assemblages inhabiting the continental shelf around Antarctica are known to be very patchy, in large part due to deep iceberg impacts. The present study shows that richness and abundance…1 January, 2007 by Chester Sands, Katrin Linse
The bivalve Lissarca notorcadensis is one of the most abundant species in Antarctic waters and has colonised the entire Antarctic shelf and Scotia Sea Islands. Its brooding reproduction, low dispersal…1 January, 2007
Rapid identification of yeast isolates from clinical samples is particularly important given their innately variable antifungal susceptibility profiles. We present here an analysis of the utility of PCR amplification and…1 January, 2007 by Claus-Dieter Hillenbrand, Michael Meredith
Drake Passage opening has often been viewed as a single, discrete event, possibly associated with abrupt changes in global circulation and climate at or near the Eocene-Oligocene boundary. A new…Read more on Drake Passage and Cenozoic climate: An open and shut case?
1 January, 2007 by Katrin Linse
Epimeria schiaparelli sp. nov. from the Ross Sea, Antarctica, is described in detail. The new species occurs on the shelf in 130–350 m depth. Epimeria schiaparelli can be distinguished from…1 January, 2007 by Hua Lu, Richard Horne
The relative effects of solar irradiance and geomagnetic activity on the atmospheric temperature anomalies (Ta) are examined from the monthly to interdecadal timescales. Geomagnetic Ap (Ap) signals are found primarily…Read more on Atmospheric temperature responses to solar irradiance and geomagnetic activity
1 January, 2007
Evidence suggests that C4 grasses, adapted to conditions of low CO2, high temperatures, and water-stressed environments, expanded relatively quickly, and in several geographically distinct regions, during the Late Miocene (approximately…Read more on Modelling Late Oligocene C4 grasses and climate
1 January, 2007
Three juvenile narwhals captured during August 1998 in the northeast of Svalbard, Norway, were equipped with satellite-relayed data loggers (SRDLs) that transmitted diving and swim-speed data, in addition to location,…1 January, 2007 by Povl Abrahamsen, Keith Makinson, Keith Nicholls
Introduction Over the Antarctic continental shelves, the focus of attention has been on the export of cold dense shelf waters to the world’s deep ocean and their contribution to Antarctic…Read more on Oceanographic processes near the Filchner Sill – plans for fieldwork in 2007
1 January, 2007 by Gareth Marshall
In this short communication we examine the relationship between the Southern Hemisphere Annular Mode (SAM) and Antarctic near-surface temperatures using data from Antarctic stations for 1957-2004. This near half-century period…1 January, 2007
Centennial climate variability over the last ice age exhibits clear bipolar behavior. High-resolution analyses of marine sediment cores from the Iberian margin trace a number of associated changes simultaneously. Proxies…1 January, 2007 by Sandra McInnes, Sandra McInnes
The major increase in distribution records of limno-terrestrial tardigrades over the last ten years has enabled us to reassess the global biogeography of the Tardigrada using cluster analysis, principal components…Read more on An attempt to revisit the global biogeography of limno-terrestrial Tardigrada
1 January, 2007 by Kevin Newsham
We examined the influence of elevated UV-B radiation on the extractability of carbohydrates from leaf litter of Quercus robur. Saplings were exposed to a 30% elevation above the ambient level…1 January, 2007 by Nigel Meredith, Richard Horne, Sarah Glauert
Energetic electrons (E > 100 keV) in the Earth's radiation belts undergo Doppler-shifted cyclotron resonant interactions with a variety of whistler mode waves leading to pitch angle scattering and subsequent…1 January, 2007
Decadal hindcast simulations of Arctic Ocean sea ice thickness made by a modern dynamic-thermodynamic sea ice model and forced independently by both the ERA-40 and NCEP/NCAR reanalysis data sets are…1 January, 2007
An automated gas chromatograph with sample pre-concentration for the measurement of peroxyacetylnitrate (PAN) was constructed with a minimum detection limit below 1 pptv. This instrument was deployed at the British…1 January, 2007 by Lloyd Peck, Simon Morley
Low temperature limits the rate of biochemical reactions and aerobic scopes of cold water ectotherms. To compensate for this limiting effect, animals living in cold environments often possess physiological or…1 January, 2007 by Mervyn Freeman
We compare the probability distributions of substorm magnetic bay magnitudes from observations and a minimal substorm model. The observed distribution was derived previously and independently using the IL index from…1 January, 2007 by Lloyd Peck, Simon Morley
Seasonal dormancy is a widespread mechanism for reducing energy expenditure during periods of low energy availability. Seasonal variation in activity and the cost of pumping water through the siphons were…1 January, 2007 by Andrew Clarke, Andrew Fleming, Eugene Murphy, Geraint Tarling, Iain Staniland, Jaume Forcada, Jonathan Watkins, Martin Collins, Michael Meredith, Nadine Johnston, Peter Enderlein, Paul Rodhouse, Philip Trathan, Peter Ward, Sally Thorpe, Simeon Hill
The Scotia Sea ecosystem is a major component of the circumpolar Southern Ocean system, where productivity and predator demand for prey are high. The eastward-flowing Antarctic Circumpolar Current (ACC) and…1 January, 2007 by Eugene Murphy, Jaume Forcada, Jonathan Watkins, Michael Meredith, Nadine Johnston, Philip Trathan, Sally Thorpe
Determining how climate fluctuations affect ocean ecosystems requires an understanding of how biological and physical processes interact across a wide range of scales. Here we examine the role of physical…Read more on Climatically driven fluctuations in Southern Ocean ecosystems
1 January, 2007 by Andy Smith
For over 2-years we have collected GPS data similar to 40 km upstream of the grounding line on Rutford Ice Stream, West Antarctica. Here we examine deviations from mean downstream…1 January, 2007 by Anje-Margriet Neutel
Understanding how complex food webs assemble through time is fundamental both for ecological theory and for the development of sustainable strategies of ecosystem conservation and restoration. The build-up of complexity…Read more on Reconciling complexity with stability in naturally assembling food webs
1 January, 2007 by Kevin Newsham
1. Predicting the effects of warming and species loss on ecosystems are two significant challenges currently facing ecologists. However, little is known of the interactive effects of these two factors.…Read more on Interactive effects of warming and species loss on model Antarctic microbial food webs
1 January, 2007 by Eugene Murphy, Philip Trathan
A recent review by Ainley et al. has suggested that recent investigations of the ecological structure and processes of the Southern Ocean have “almost exclusively taken a bottom-up, forcing-by-physical-processes approach…1 January, 2007 by Robert Larter
The Amundsen Sea continental shelf is one of the most remote areas of coastal Antarctica and was relatively unexplored until the late 1980s. Over the last two decades, increased oceanographic…1 January, 2007 by Robert Larter
[1] Marine geophysical data from the Antarctic continental shelf indicate the former presence of ice streams that drained through bathymetric troughs during the last glacial cycle. Streaming flow is recorded…Read more on Till characteristics, genesis and transport beneath Antarctic paleo-ice streams
1 January, 2007
We investigated the shielding against solar ultraviolet radiation and inducible damage, as well as the short-term response of whole animal metabolic rate in two Antarctic shallow water amphipod species. Light…1 January, 2007 by Andrew Wood, Richard Phillips
A total of 547 sightings of 291 banded wandering albatrosses Diomedea exulans and 21 sightings of 14 banded giant petrels Macronectes spp. were made from toothfish longliners operating on the…1 January, 2007 by Eric Wolff
The EPICA (European Project for Ice Coring in Antarctica) Dome C drilling in East Antarctica has now been completed to a depth of 3260 m, at only a few meters…Read more on The EDC3 chronology for the EPICA Dome C ice core
1 January, 2007 by Richard Hindmarsh, Richard Hindmarsh
The relationship between velocity field and isochrone geometry along a steady flowline of an ice sheet is examined. The method is analytical and based upon the stream function and its…