Showing 11205 items
1 January, 2008
Aim To determine patterns in diversity of a major Antarctic plant species, including relationships of Antarctic populations with those outside the Antarctic zone. Location Antarctic Peninsula, Maritime Antarctica, sub-Antarctic islands,…1 January, 2008 by David Barnes, Huw Griffiths
Aim To describe the distribution of biodiversity and endemism of bryozoans in southern temperate and polar waters. We hypothesized that we would find: (1) no strong latitudinal richness gradient; (2)…Read more on Biodiversity and biogeography of southern temperate and polar bryozoans
7 December, 2007 by Gareth Chisham, Mervyn Freeman
We present a detailed analysis of the spatial structure of the ionospheric plasma velocity in the nightside F-region ionosphere, poleward of the open-closed magnetic field line boundary (OCB), i.e. in…1 November, 2007 by John Turner, Simeon Hill
Fisheries scientists habitually consider uncertainty in parameter values, but often neglect uncertainty about model structure. The importance of this latter source of uncertainty is likely to increase with the greater…Read more on Model uncertainty in the ecosystem approach to fisheries
1 November, 2007
We present an analysis of a long-term archive of horizontal wind data derived from meteor wind observations from a SuperDARN radar at Halley, Antarctica (76S, 27W). Systematic differences between the…1 November, 2007
Spiracle and tracheal structure in the extant Ixodida is revised and shown to comprise 29 distinct component characters, some of which are common to all Anactinotrichida, while others are unique…1 October, 2007 by Nigel Meredith, Richard Horne, Sarah Glauert
During the Halloween Storm period (October–November 2003), a new Van Allen belt electron population was powerfully accelerated. The inner belt of electrons formed in this process decayed over a period…Read more on Low-altitude measurements of 2–6 MeV electron trapping lifetimes at 1.5 ≤ L ≤ 2.5
1 September, 2007 by Mark Clilverd
In this study we investigate periods of enhanced ionization in the mesosphere during Northern Hemisphere wintertime. Long-lasting ionization enhancements (days) are typically produced by solar proton events or by the…1 September, 2007 by Nigel Meredith, Richard Horne, Sarah Glauert
Local acceleration is required to explain electron flux increases in the outer Van Allen radiation belt during magnetic storms. Here we show that fast magnetosonic waves, detected by Cluster 3,…Read more on Electron acceleration in the Van Allen radiation belts by fast magnetosonic waves
1 August, 2007 by Nigel Meredith
Using ray tracing and suprathermal electron distributions from CRRES, the final propagation latitudes of typical chorus rays are calculated as a function of L, MLT, AE, and initial wave normal…Read more on Ray tracing of penetrating chorus and its implications for the radiation belts
1 August, 2007 by David Vaughan, Hugh Corr
Airborne radio echo sounding of the West Antarctic Ice Sheet over Pine Island Glacier was performed in the austral summer of 2004/2005 under the National Science Foundation's West Antarctic Ice…18 July, 2007 by Mark Clilverd, Tracy Moffat-Griffin
. In the polar atmosphere, significant chemical and ionization changes occur during solar proton events (SPE). The access of solar protons to this region is limited by the dynamically changing…Read more on Improved dynamic geomagnetic rigidity cutoff modeling: testing predictive accuracy
1 June, 2007 by Mark Clilverd
We report GOMOS nighttime observations of middle atmosphere NO2 and O-3 profiles during eight recent polar winters in the Arctic and Antarctic. The NO2 measurements are used to study the…Read more on Arctic and Antarctic polar winter NOx and energetic particle precipitation in 2002-2006
1 June, 2007 by Nigel Meredith
Wave-particle interactions lead to the loss of relativistic electrons from the outer radiation belt on timescales ranging from hours to weeks. For a fixed value of chorus wave amplitudes pitch-angle…1 April, 2007 by Mervyn Freeman
We re-examine whether substorms are triggered by solar wind fluctuations or an internal magnetospheric instability by comparing the statistical associations between substorm onsets and (1) an external trigger definition, (2)…1 March, 2007 by John King
We examine the sensitivity of the modelled climate of the third generation Hadley Centre climate model to changes in the parametrization of surface and boundary-layer fluxes under stable stratification. Replacing…1 March, 2007 by John Turner, Thomas Lachlan-Cope
This paper investigate the large mean sea level pressure errors in the HadCM3 atmosphere-ocean global climate model around Antarctica and finds them to be caused by the sea surface temperature…24 February, 2007 by Eric Wolff
Sea salt and mineral dust records as represented by Na+ and Ca2+ concentrations, respectively, in Greenland and Antarctic ice cores show pronounced glacial/interglacial variations. For the Last Glacial Maximum (LGM)…1 February, 2007 by Eugene Murphy, Jonathan Watkins, Sally Thorpe
Antarctic krill, Euphausia superba Dana, has a heterogeneous circumpolar distribution in the Southern Ocean. Krill have a close association with sea ice which provides access to a critical food source…1 January, 2007
Following the PPARC programmatic review announced in the spring of last year, with its gloomy outlook for solar–terrestrial physics, three young scientists in the field mobilized the junior members of…1 January, 2007 by Richard Horne
Relativistic electrons in the outer Van Allen belt wreak havoc with satellites in geosynchronous orbit, but how they reach such high energies has been unclear. New data identify gyro-resonant wave-particle…Read more on Plasma astrophysics: Acceleration of killer electrons
1 January, 2007 by Eric Wolff, Robert Mulvaney
Ice core records of methanesulfonic acid (MSA) from three sites around the Weddell Sea are investigated for their potential as sea ice proxies. It is found that the amount of…1 January, 2007 by Jaume Forcada
This paper presents baseline information on maternal behaviour and lactation in the Mediterranean monk seal, with particular focus on the age at which pups are weaned. The study was conducted…1 January, 2007
During recent cruises aboard RV Polarstern in the Antarctic Peninsula region, a new species of benthic octopodid was discovered whose generic affinities based on morphological characteristics were uncertain. Molecular sequence…Read more on A new species of Pareledone (Cephalopoda: Octopodidae) from Antarctic Peninsula Waters
1 January, 2007
We measured the photoformation of hydroxyl radical (OH) on snow grains at Summit, Greenland during the spring and summer. Midday rates of OH formation in the snow phase in the…Read more on Photoformation of hydroxyl radical on snow grains at Summit, Greenland
1 January, 2007
1-D profiles and time series from an idealised atmospheric boundary layer model are presented, which show agreement with boundary layer measurements of polar NOx. Diffusion models are increasingly being used…Read more on Behaviour of tracer diffusion in simple atmospheric boundary layer models
1 January, 2007 by Andrew Clarke, Lloyd Peck
Benthic communities living in shallow-shelf habitats in Antarctica (Read more on Climate change and invasibility of the Antarctic benthos
1 January, 2007 by Robert Mulvaney
Trends of carbon monoxide (CO) for the past 100 years are reported as derived from Antarctic firn drilling expeditions. Only one of 3 campaigns provided high quality results. The trend…1 January, 2007 by David Barnes
A decade has yielded much progress in understanding polar disturbance and community recovery—mainly through quantifying ice scour rates, other disturbance levels, larval abundance and diversity, colonization rates and response of…Read more on Disturbance, colonization and development of Antarctic benthic communities
1 January, 2007 by David Barnes
Hermit crabs are an obvious, common and abundant feature of global shallow water environments but almost nothing is known of their ecology at their extreme latitudinal ranges, the Arctic and…Read more on Richness, abundance and shell use of subarctic and arctic hermit crabs
1 January, 2007 by David Barnes, Katrin Linse
Climate is altering rapidly in parts of the Arctic and Antarctic but we know little about how marine organisms are responding to, or might respond to such changes. Knowledge of…Read more on Growth rate and its variability in erect Antarctic bryozoans
1 January, 2007 by Claus-Dieter Hillenbrand
The direct record of Late Miocene–Early Pliocene Antarctic Peninsula Ice Sheet expansions from a previously published seismostratigraphic study of the outer shelf at Ocean Drilling Program Site 1097 is compared…1 January, 2007
We investigated the ability of four species of marine zooplankton to synthesize polyunsaturated fatty acids (PUFAs) during pulse-chase tracer experiments. Liposomes containing a deuterium labelled precursor fatty acid, D5-18:3n-3, were…1 January, 2007
Subglacial bed conditions exert a significant control on ice stream behavior and evolution, and can be characterized by determining bed roughness from FFT analysis of radar-imaged basal reflectors. Here we…1 January, 2007 by Michael Meredith, Sally Thorpe
Responses by marine top predators to environmental variability have previously been almost impossible to observe directly. Using novel, animal-mounted instruments simultaneously recording movements, diving behaviour and in-situ oceanographic properties, we…1 January, 2007 by Anna Jones, Howard Roscoe
OH and HO2 radical concentrations have been measured in the boundary layer of coastal Antarctica for a six-week period during the austral summer of 2005. The measurements were performed at…Read more on Observations of OH and HO2 radicals in coastal Antarctica
1 January, 2007
Eco-physiological variation and local adaptation are key issues in microbial ecology. Here, we investigated the thermal adaptation of 19 strains of the same Spumella morphospecies (Chrysophyceae, Heterokonta). In order to…1 January, 2007 by Peter Convey
Antarctic terrestrial ecosystems have poorly developed soils and currently experience one of the greatest rates of climate warming on the globe. We investigated the responsiveness of organic matter decomposition in…1 January, 2007 by Peter Convey
Antarctic terrestrial ecosystems are nutrient-poor and depend for their functioning in part on external nutrients. However, little is known about the relative importance of various sources. We measured external mineral…1 January, 2007 by Peter Convey
Antarctic soil ecosystems are amongst the most simplified on Earth and include only few soil arthropod species, generally believed to be opportunistic omnivorous feeders. Using stable isotopic analyses, we investigated…Read more on Food choice of Antarctic soil arthropods clarified by stable isotope signatures
1 January, 2007 by Peter Convey
Background: Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During…1 January, 2007 by Nigel Meredith
In the present paper, phase space density functions of the form f(v) = A N /v n are fitted to statistical distributions of suprathermal electron fluxes (E = 0.213–16.5 keV)…1 January, 2007 by Andrew Clarke, Lloyd Peck
The energetic cost of protein synthesis is thought to account for a significant proportion of total metabolism. However, attempts to estimate the energetic cost of synthesizing proteins have resulted in…1 January, 2007 by Robert Larter
Large-scale streamlined glacial landforms are identified in 11 areas of northwest Scotland, from the Isle of Skye in the south to the Butt of Lewis in the north. These ice-directional…1 January, 2007 by Katrin Linse
Our knowledge of the biodiversity of the Southern Ocean (SO) deep benthos is scarce. In this review, we describe the general biodiversity patterns of meio-, macro- and megafaunal taxa, based…Read more on The biodiversity of the deep Southern Ocean benthos
1 January, 2007 by Katrin Linse
Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some…Read more on First insights into the biodiversity and biogeography of the Southern Ocean deep sea
1 January, 2007
The chironimid midge Eretmoptera murphyi has been introduced to Signy Island and has since become established at a single site. Viable propagules of a diverse range of micro-fungi were recovered…1 January, 2007
Polymerase chain reaction (PCR) primers ST1 and ST2 were designed for the specific amplification of ribosomal DNA from Stropharia aurantiaca, and a nested PCR method was developed for the detection…1 January, 2007 by David Pearce, Peter Convey
Inland Antarctic terrestrial ecosystems and biodiversity are poorly understood in comparison with Antarctic coastal regions. Microorganisms, as primary colonists, are integral to Antarctic soil ecosystem development, essential for pedogenesis and…Read more on The cyanobacterial community of polygon soils at an inland Antarctic nunatak
1 January, 2007 by Lloyd Peck
Polar conditions (low and stable seawater temperature coupled with highly seasonal primary productivity) constrain reproduction in benthic invertebrates. The reproductive cycle of the common Antarctic sea urchin Sterechinus neumayeri was…1 January, 2007 by Lloyd Peck
The fish species Notothenia angustata inhabits temperate waters (10 °C), yet retains physiological traits that show it once existed at sub-zero temperatures. We determined the free-ranging activity, heart rate and…1 January, 2007
The growth rate of atmospheric carbon dioxide (CO2), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes…1 January, 2007 by Melody Clark
Background: Duplicated genes are common in vertebrate genomes. Their persistence is assumed to be either a consequence of gain of novel function (neofunctionalisation) or partitioning of the function of the…Read more on Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus
1 January, 2007
An interpretative modeling analysis is conducted to simulate the diurnal variations in OH and HO2 + RO2 observed at Summit, Greenland in 2003. The main goal is to assess the…1 January, 2007 by Geraint Tarling
Backscattering strength was estimated from 127 shipboard surveys with an acoustic Doppler current profiler (ADCP) made during Drake Passage transits from 1999 to 2004. The backscattering strength is used to…1 January, 2007 by Gareth Chisham, Mervyn Freeman, Michael Pinnock
The Super Dual Auroral Radar Network (SuperDARN) has been operating as an international co-operative organisation for over 10 years. The network has now grown so that the fields of view…1 January, 2007 by Peter Convey
Antarctica and its surrounding islands lie at one extreme of global variation in diversity. Typically, these regions are characterized as being species poor and having simple food webs. Here, we…Read more on Spatial and temporal variability across life’s hierarchies in the terrestrial Antarctic
1 January, 2007
Geomagnetic pulsation in the Pc3–4 bands have been studied at high Antarctic latitudes during the local summer. The statistical relation between the occurrence probability of Pc3 and Pc4 pulsations and…1 January, 2007 by Lloyd Peck, Melody Clark
We describe the levels of natural arm damage in the Antarctic brittle star Ophionotus victoriae and the rate of arm regeneration over the period of 1 yr, as measured in…Read more on Delayed arm regeneration in the Antarctic brittlestar Ophionotus victoriae
1 January, 2007 by Michael Thorne, Roger Worland, Melody Clark
Background Ice, snow and temperatures of -14°C are conditions which most animals would find difficult, if not impossible, to survive in. However this exactly describes the Arctic winter, and the…1 January, 2007 by Andrew Clarke, David Barnes, Huw Griffiths, Alistair Crame, Katrin Linse
The aim of this study was to use data for gastropod and bivalve molluscs to determine whether the fauna of the Southern Ocean is sufficiently well known to establish robust…1 January, 2007 by Andrew Clarke, Eugene Murphy, Nadine Johnston
Antarctica offers a unique natural laboratory for undertaking fundamental research on the relationship between climate, evolutionary processes and molecular adaptation. The fragmentation of Gondwana and the development of wide-scale glaciation…1 January, 2007 by Andrew Clarke, David Barnes, Eugene Murphy, John King, Lloyd Peck, Michael Meredith
The Antarctic Peninsula is experiencing one of the fastest rates of regional climate change on Earth, resulting in the collapse of ice shelves, the retreat of glaciers and the exposure…Read more on Climate change and the marine ecosystem of the western Antarctic Peninsula
1 January, 2007 by Mark Clilverd, Nigel Meredith, Richard Horne, Sarah Glauert
The tilt and offset of the Earth's magnetic field can significantly affect the longitudinal and seasonal distribution of electron density in the plasmasphere. Here we show that for the solar…1 January, 2007 by Mark Clilverd
Precipitation of relativistic electrons into the atmosphere has been suggested as the primary loss mechanism for radiation belt electrons during large geomagnetic storms. Here we investigate the geographical spread of…1 January, 2007 by David Pearce
We launched a cryptoendolithic habitat, made of a gneissic impactite inoculated with Chroococcidiopsis sp., into Earth orbit. After orbiting the Earth for 16 days, the rock entered the Earth's atmosphere…1 January, 2007
We report on a case of left main bronchus occlusion by an inhaled foreign body at a remote Antarctic scientific base during the austral winter. We present the dilemmas of…1 January, 2007 by Martin Collins, Mark Belchier
The distribution and diet of juvenile (1 January, 2007 by Thomas Bracegirdle
We assess 19 coupled models from the IPCC fourth assessment report archive from the simulation of the 20th century, based on the calculation of " skill scores.'' The models show…Read more on An Antarctic assessment of IPCC AR4 coupled models
1 January, 2007
We measured egg hatching tunes and stage specific naupliar development tinges of the key calanoid copepods Calanus helgolandicus and C. finmarchicus in response to temperature, food quantity and food type.…1 January, 2007 by Geraint Tarling
Antarctic krill Euphausia superba are key to most Antarctic ecosystems, particularly at South Georgia, where penguins and seals rely on them for their breeding success each summer. Changes in krill…Read more on Behaviour affects local-scale distributions of Antarctic krill around South Georgia
1 January, 2007 by Geraint Tarling, Philip Trathan
Question: How does the female macaroni penguin balance her own needs with those of her chick during breeding? Features of the model: We model the behaviour of female macaroni penguins…1 January, 2007
Glacial and post-glacial shelf sedimentation near the Larsen C and former Larsen B ice shelves is compared to records from ice shelves farther north, which underwent mid-Holocene retreat. A core…1 January, 2007
The growing world population increases the demand for water, energy, and land. This demand for natural resources impacts the transport of material and the supply of nutrients in the coastal…Read more on Potential impact of changes in river nutrient supply on global ocean biogeochemistry.
1 January, 2007 by Sandra McInnes, Sandra McInnes
Low Lake, a freshwater pool at Cape Denison, Commonwealth Bay, Antarctica (67 degrees 20'40"S; 142 degrees 40'45 '' E) was sampled for protists and invertebrates. Forty species of protists were…Read more on Low life in Low Lake, a freshwater pool at Commonwealth Bay, Antarctica
1 January, 2007 by Vsevolod Afanasyev
In most long-lived animal species, juveniles survive less well than adults. A potential mechanism is inferior foraging skills but longitudinal studies that follow the development of juvenile foraging are needed…1 January, 2007
We present a detailed statistical analysis of acoustic emission time series from laboratory rock fracture obtained from different experiments on different materials including acoustic emission controlled triaxial fracture and punch-through…1 January, 2007 by Eugene Murphy, Mervyn Freeman, Richard Phillips, Vsevolod Afanasyev
The study of animal foraging behaviour is of practical ecological importance1, and exemplifies the wider scientific problem of optimizing search strategies2. Lévy flights are random walks, the step lengths of…Read more on Revisiting Lévy flight search patterns of wandering albatrosses, bumblebees and deer
1 January, 2007 by Katrin Linse
We examined deep-sea benthic data on polychaetes, isopods and bivalves from the Atlantic sector of the Southern Ocean. Samples were taken during the expeditions EASIZ II (1998), ANDEEP I and…1 January, 2007
The hydroxyl (OH) rotational temperature and band emission rate have been derived using year-round, ground-based measurements of the infrared OH nightglow from Sweden from 1991 to 2002. Recent work has…Read more on Seasonal variation in the correlation of airglow temperature and emission rate
1 January, 2007 by Geraint Tarling
A series of eight replicated acoustic surveys, four by day and four by night, was undertaken in Gullmarsfjord on the Swedish west coast during two 24-h periods on 8 and…1 January, 2007 by Peter Ward, Sophie Fielding
Net sampling within the vicinity of the Crozet archipelago, in the Indian Ocean sector of the Southern Ocean, was conducted during late spring/summer (November 2004-January 2005) to describe the composition,…1 January, 2007 by Eric Wolff, Robert Mulvaney
Continuous sea salt and mineral dust aerosol records have been studied on the two EPICA (European Project for Ice Coring in Antarctica) deep ice cores. The joint use of these…1 January, 2007
[1] During the Northern Hemisphere summer, absorbed solar radiation melts snow and the upper surface of Arctic sea ice to generate meltwater that accumulates in ponds. The melt ponds reduce…Read more on A continuum model of melt pond evolution on Arctic sea ice
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…